CHAPTER VI 6.1 ANALYTICAL METHODSshodhganga.inflibnet.ac.in/bitstream/10603/12764/18... · Ciprofloxacin HCl is official in IP 20071 , B.P 2 and USP 24/NF 193. A number of methods

248

CHAPTER VI

6.1 ANALYTICAL METHODS

6.1.1 UV Spectrophotometric method for the estimation of ciprofloxacin HCl Ciprofloxacin HCl is official in IP 20071

, B.P2 and USP 24/NF 193. A number of

methods were reported for the estimation of ciprofloxacin HCl in pharmaceutical

preparations and biological fluids4-8.

Method used for the estimation of ciprofloxacin HCl

A spectrophotometric method based on the measurement of absorbance at 276

nm in 0.1 N HCl was used in the present study for the estimation of ciprofloxacin HCl.

Materials:

1. Ciprofloxacin HCl (gift sample from Darvin private Laboratories Ltd.)

2. Hydrochloric acid (Finar Chemicals limited, Ahmedabad)

Standard solution:

100 mg of ciprofloxacin HCl was dissolved in 0.1 N HCl in 100 ml of

volumetric flask and the solution was made upto volume with 0.1 N HCl.

Procedure:

The standard solution of ciprofloxacin HCl was subsequently diluted with 0.1 N

HCl to obtain a series of dilutions containing 1, 2, 3, 4 and 5 µg of ciprofloxacin HCl in

1 ml solution. The absorbance of these solutions was measured at 276 nm using UV-VIS

spectrophotometer (ELICO, Model SL 1500) against blank. The concentrations of

ciprofloxacin HCl and the corresponding absorbances are given in the Table 6.1.1.A. The

absorbances were plotted against concentration of ciprofloxacin HCl as shown in Fig.

6.1.1.A.

249

Validation of the method:

1. Reproducibility:

Reproducibility of the above method was studied by analyzing six individually

weighed samples of ciprofloxacin HCl. The present relative standard deviation (RSD)

of the determination found to be lessthan 1.0%.

2. Interference Study:

The interference in the above method by the Indion 414, Indion 254, stearic acid,

PEG 1500 and other materials used in the present investigation was studied by

testing their effects individually. Accurately weighed amounts of ciprofloxacin HCl

and Indion 414, Indion 254, stearic acid, PEG 1500 and other materials in 1:1 ratio

were mixed thoroughly. From each mixture, an accurately weighed powder

equivalent to 100 mg of ciprofloxacin HCl was assayed by the method described

above. The ciprofloxacin HCl contents were calculated using the calibration curve

(Fig. 6.1.1.A) and the results are given in Table 6.1.1.B.

250

Table 6.1.1.A: Calibration curve for the estimation of ciprofloxacin HCl in

0.1 N HCl

Ciprofloxacin HCl concentration

(µg/ml)

Absorbance

RSD

1

2

3

4

5

0.088

0.185

0.279

0.361

0.465

0.007

0.008

0.004

0.006

0.004

Fig. 6.1.1.A: Calibration curve of ciprofloxacin HCl in 0.1 N HCl

Table 6.1.1.B: Amounts of ciprofloxacin HCl estimated in interference

studies

Material Amount of

ciprofloxacin HCl

Added (mg)

Amount

estimated

(mg)

Percent

estimated

(Recovery)

Indion 414

Indion 254

PVP k 30

Stearic acid

PEG 1500

Mannitol

Sodium CMC

Xanthan gum

100

100

100

100

100

100

100

100

99.82

99.90

99.78

99.84

99.74

99.90

99.75

99.84

99.82

99.90

99.78

99.84

99.74

99.90

99.75

99.84

y = 0.092x - 0.001R² = 0.999

0

0.1

0.2

0.3

0.4

0.5

0.6

0 2 4 6

Abso

rban

ce

Concentration (µg/ml)

251

Discussion

The method obeyed Beer’s law in the concentration range of 1-5µg/ml, low RSD

(<0.005) values indicated reproducibility of the method in 0.1 NHCl. In order to find the

degree of linear relationship, correlation coefficient (r) was calculated. It was found to be

0.9996 in 0.1 N HCl, which indicated a high degree of correlation. Next it was of interest

to establish the mathematical form of linear relationship between the two variables

(concentration and absorbance) under consideration and the equation obtained were

Y=0.1289X+0.0067 for 0.1 N HCl, where X is the concentration of ciprofloxacin HCl

(µg/ml) and Y is the absorbance.

The results given in Table 6.1.1.B indicated that none of the resins and other

materials interfered in the method of estimation. Thus the method was found to be

suitable for the estimation of ciprofloxacin HCl contents in various products and in in

vitro dissolution studies.

252

6.1.2 DEVELOPMENT OF A NEW HPLC METHOD FOR

ESTIMATION OF CIPROFLOXACIN HCl IN RABBIT PLASMA

A new reverse phase HPLC method with UV detection was developed for the

estimation of ciprofloxacin HCl in plasma samples. For this purpose a calibration curve

was constructed by analyzing plasma samples containing different amounts of

ciprofloxacin HCl as follows.

Chemicals and solvents

Ciprofloxacin HCl reference standard

Glacial acetic acid (AR grade)

Acetonitrile (ACN) (HPLC grade)

Methanol (HPLC grade)

Milli-Q water

Rabbit plasma

0.45 µ Membrane filter

Instrumentation

The experiment was conducted to develop a liquid chromatographic method for

the determination of ciprofloxacin HCl using Waters Alliance 2695, HPLC system with

Auto Sampler and 2487 UV-Visible detector. The chromatographic studies were

performed using Hypersil C18 column (4.5 ID X 150 mm, 3.5µ) at ambient temperature.

Data acquisition was done by using Empower 2 software. The details of the instruments

employed in the study are as follows.

253

Equipment Model

HPLC System Waters Alliance 2695

Microbalance Afcoset

Centrifuge Remi

Vacuum pump Millipore

Refrigerator Samsung

pH meter Adwa

Micropipettes, Multi pipette and Micro tips Brand and Eppendorf

Water Purification System Elix 10 / Milli-Q gradient

1.5 ml poly propylene tubes Eppendorf

Ultra sonicator Power Sonic510, (Hwashin Technology)

cyclomixer Remi

Drug stock solution of the drug

About 10.0 mg of ciprofloxacin HCl was weighed accurately and transferred into

a 10 ml volumetric flask containing 5 ml of methanol. The contents were sonicated for 5

minutes and then the volume made up with a further quantity of methanol to get a free

base concentration of 1 mg/ml. Store this stock solution of the drug in a refrigerator at a

temeperature below 100C.

Secondary stock solution of the drug

1 ml of the drug stock solution was diluted up to 10 ml in a volumetric flask using

mobile phase (2% Acetic Acid and ACN in a ratio of 60:40 v/v) as the diluent to get the

100 µg/ml. Store the secondary stock solution of the drug in a refrigerator at a

temeperature below 100C.

254

Calibration curve dilutions

The calibration curve dilutions were prepared from secondary stock solution as

per the table given below in the concentration range of 3.00 to 30.00 µg/ml using mobile

phase (2% Acetic Acid and ACN in a ratio of 60:40 v/v) as the diluent. These dilutions

were subsequently used for spiking the blank plasma.

Stock/SS ID Stock/SS Conc. (µg/ml)

Stock/SS volume (ml)

Made up to Vol. (ml)

Final Conc. (µg/ml) **SS ID

Secondary stock 100.00 3.00 10 30.00 SS-6

SS-6 30.00 5.00 10 15.00 SS-5

SS-6 30.00 4.00 10 12.00 SS-4

SS-6 30.00 3.00 10 9.00 SS-3

SS-6 30.00 2.00 10 6.00 SS-2

SS-6 30.00 1.00 10 3.00 SS-1

**SS: Spiking solution

Spiked calibration curve plasma standards

The above calibration curve dilutions were used to spike the blank rabbit plasma

to prepare the plasma calibration curve standards ranging from 1.00 to 5.00 µg/ml as per

the table given below.

To five hundred micro liters of the spiking solution, 0.5 ml of plasma and 0.5 ml

of ACN were added in to 1.5 ml of poly propylene tubes. The tubes were vortex-mixed

for 5 minutes in cyclomixer and then centrifuged for 10 min. at 4000 rpm. The upper

organic layers of the tubes were collected, filtered and injected into the column and then

analyzed by HPLC.

255

Stock/SS ID

Stock/SS Conc. (µg/ml)

Spiking solution

(ml)

Plasma volume

(ml)

Made up to with

ACN (ml) Final Conc.

(µg/ml)

CC Standard

ID

SS-5 15.00 0.500 0.500 1.50 5.00 STD -5

SS-4 12.00 0.500 0.500 1.50 4.00 STD -4

SS-3 9.00 0.500 0.500 1.50 3.00 STD -3

SS-2 6.00 0.500 0.500 1.50 2.00 STD -2

SS-1 3.00 0.500 0.500 1.50 1.00 STD -1

2% Acetic acid solution

2 ml of glacial acetic acid was transferred into a 100 ml volumetric cylinder and

the volume was made up to with Milli-Q water.

Mobile Phase

The mobile phase was prepared by mixing 60 parts of 2% acetic acid and 40 parts

of ACN in a reagent bottle and sonicated for 5 minutes. The solution was stored at room

temperature and used within 3 days from the date of preparation.

Rinsing solution

700 ml of methanol was transferred into a 1000 ml reagent bottle, 300 ml of Milli-

Q water was added, mixed and sonicated for 5 minutes. The solution was stored at room

temperature and used within 7 days from the date of preparation. This solution was used

for rinsing the injection needle of the HPLC instrument.

Method development and optimization of the chromatographic conditions

For developing the method for the assay of ciprofloxacin HCl, a systematic study

of the effect of various factors was undertaken by varying one parameter at a time and

keeping all the other conditions constant. The following studies were conducted for this

256

purpose. A non-polar Hypersil C18 column was chosen as the stationary phase for this

study.

The mobile phase and the flow rate

In order to get sharp peaks and base line separation of the components, to carried

out a number of experiments by varying the commonly used solvents, their compositions

and flow rate.

To effect ideal separation of the drug under isocratic conditions, mixtures of

commonly used solvents like water, methanol and acetonitrile with or without buffers in

different combinations were tested as mobile phases on a C18 stationary phase. A binary

mixture of 2% acetic acid and ACN in a ratio of 60:40 v/v was proved to be the most

suitable of all the combinations since the chromatographic peaks obtained were well

defined and resolved and free from tailing.

A mobile phase flow rate of 1.0 ml/min. was found to be suitable in the study

range of 0.5-1.5 ml/min.

Detection wave length

The UV absorption spectrum of the drug was taken in methanol and the λ max

was found to be at 280 nm. Hence detection of the drug was monitored at 280 nm.

Retention time of ciprofloxacin HCl

Model chromatogram showing the separation ciprofloxacin HCl is presented in

Fig. 6.1.2.B under the above optimized conditions retention time of 2.870 minutes was

obtained for ciprofloxacin HCl.

257

Data acquisition and processing

The chromatograms were obtained and data were processed by the peak area

method using the Empower 2 software. The concentrations of the unknown samples were

calculated from the following equation of the regression analysis of the spiked plasma

calibration graph.

Y = m X + C

X = Analyte concentration

Y = Analyte area

m = Slope of the calibration curve

Optimized chromatographic conditions

Parameter Value

Column Hypersil C18

(4.5 X 150 mm, 3.5µ)

Mobile phase 2% Acetic Acidand ACN (70:30 v/v)

Flow rate 1.0 ml/min

Run time 6.0 min

Column oven temperature Ambient

Auto sampler temperature Ambient

Volume of injection 20 μL

Detection wave length 280 nm

Retention time of

Ciprofloxacin HCl

2.870 min.

258

Fig. 6.1.2.A: Chromatogram obtained with blank plasma

Fig. 6.1.2.B: Chromatograms obtained with blank plasma and plasma spiked with

ciprofloxacin HCl for the calibration curve

259

Table 6.1.2.A: Calibration curve for the estimation of ciprofloxacin HCl in plasma

Plasma concentration of

Ciprofloxacin HCl (µg/ml)

Mean peak

area Statistical analysis

1.00 52608 Slope = 52608

2.00 105216 Intercept = -0.1

3.00 157824 Correlation coefficient

4.00 210433 R=1

5.00 263040

Fig. 6.1.2.C: Calibration curve for the estimation of ciprofloxacin HCl in plasma

samples

y = 52608x - 0.1R² = 1

0

50000

100000

150000

200000

250000

300000

0 2 4 6

Peak

are

a

Concentration of ciprofloxacin HCl (µg/ml)

260

Validation of the HPLC method

Specificity of the method

It was shown that the method was specific, as the chromatogram of blank plasma

without added ciprofloxacin HCl showed a peak (Fig.6.1.2.A) at retention time of 1.521

minutes, may be related to plasma constituents, where as the drug relevant peak was

expected (Fig.6.1.2.B) at retention time of 2.870 minutes, with ciprofloxacin HCl spiked

plasma standard.

Accuracy

The accuracy of HPLC assay method was assessed by adding known amounts (3,

4 and 5µg) of drug to reanalyzed drug spiked plasma samples of known concentration

(5µg) and subjecting the samples to the proposed HPLC method. The study was

replicated six times. The recovery of ciprofloxacin HCl sample preparation was measured

by comparing the peak area found in plasma sample with the peak area obtained by direct

injection of pure drug standard with equivalent amounts of ciprofloxacin HCl. The results

are given in the Table 6.1.2.B.

Precision

The precision of the HPLC method was determined in terms of intra– and inter-

day variations in the peak areas for the set of drug solutions (2, 3 and 4 µg) assayed six

times on the same day and on three different days. The intra-day and inter-day variations

in the peak areas of drug were calculated in terms of coefficient of variation. The results

obtained are given in Table 6.1.2.C.

261

Linearity

The regression of drug concentration of the ciprofloxacin HCl over its peak area

was calculated by the least square method. The fitness of the data to the linear

relationship was assessed by calculating coefficient.

Table 6.1.2.B: Recovery of ciprofloxacin HCl in plasma

Amount of

drug added (µg)

Mean (± S.D) amount

(µg) recovered (n=6)

Mean (± S.D) %

of recovery (n=6)

2

3

4

1.993 ± 0.03

2.980 ± 0.02

3.957 ± 0.02

99.63 ± 1.51

99.33 ± 0.63

98.91 ± 0.48

Table 6.1.2.C: Precision of the proposed HPLC method for

ciprofloxacin HCl in plasma

Concentration of

ciprofloxacin HCl

(µg/ml)

Observed concentration of ciprofloxacin HCl (µg/ml)

Intra-day Inter-day

Mean (n=6) %CV Mean (n=6) %CV

2

3

4

1.991±0.01

2.976± 0.01

3.943±0.01

0.7344

0.2457

0.3355

1.981 ± 0.01

2.9633 ± 0.01

3.9367± 0.01

0.4331

0.3068

0.1521

262

RESULTS AND DISCUSSION

The HPLC method was developed, validated and the total run time was set at 06

minutes. Ciprofloxacin HCl was appeared on the chromatogram at 2.870 minutes as

shown in Fig. 6.1.2.B. The retention time of the drug was the same for all the six

injection samples. The regression of ciprofloxacin HCl concentration (1-5 µg/ml) over its

peak area of drug was found to be Y=52608X- 0.1 with a high correlation coefficient

(r=1), where Y is peak area and X is concentration of ciprofloxacin HCl. This regression

equation was used to estimate the amount of ciprofloxacin HCl in plasma.

The developed HPLC method was validated for intra-day and inter-day variation.

When the solutions containing 2, 3 and 4 µg/ml of ciprofloxacin HCl were injected

repeatedly on the same day and on other day, the coefficient of variation in amounts

estimated was less than 0.7345 %. The results indicated that the HPLC method is highly

reproducible. In the accuracy assessment, the recovery was found to be 98.91 - 99.63%.

Thus, the developed HPLC method is simple, sensitive, precise and highly accurate and

required only a small quantity of plasma sample. This method is applicable to the

estimation of ciprofloxacin HCl in rabbit plasma obtained in pharmacokinetic evaluation

of fast dissolving tablets and dry syrup.

REFERENCES

1. Indian Phramcopoeia. Indian Pharmacopoeia Commission, Ghaziabad, India.

(2010), vol 2: 1092-1095.

2. British Pharmacopoeia. British Pharmacopoeia Commission Office, London, U.K.

(2012), vol I & III: 525-526 &2607.

263

3. USP/NF. The United States Pharmacopeia XXVII and the National Formulary XXII.

The United States Pharmacopeial Convention, Inc. Rockville, MD. (2004), 455-

457.

4. Z. Vybiralova, M. Nobilis, J. Zoulova, J. Kvetina and P. Petr; High-performance

liquid chromatographic determination of ciprofloxacin in plasma samples. Journal of

Pharmaceutical and Biomedical Analysis. (2005), 37(5): 851-858.

5. Amina Mohamed El Brashy, Mohamed El Sayed Metwally and Fawzi Abdallah El

Sepai; Spectrophotometric determination of some fluoroquinolone antibacterials by

binary complex formation with xanthene dyes. IL Farmaco. (2004), 59(10): 809-817.

6. Lacroix PM, Curran NM and Sears RW; High-pressure liquid chromatographic

methods for ciprofloxacin hydrochloride and related compounds in raw materials.

J Pharm Biomed Anal. (1996), 14(5):641-654.

7. Ranjit Singh, Mukesh Maithani, Shailendra K. Saraf, Shubhini Saraf and Ram

C.Guptad; Simultaneous estimation of ciprofloxacin hydrochloride, ofloxacin,

tinidazole and ornidazole by reverse phase – High Performance Liquid

Chromatography. Eurasian J. Anal. Chem. (2009), 4(2): 161-167.

8. B. Aksoy, I. Kuçukguzel, and S. Rollas; Development and validation of a stability

indicating HPLC Method for determination of ciprofloxacin hydrochloride and its

related compounds in film-coated tablets. Chromatographia. (2007), 66(1): 57-63.

264

6.2 Preparation and evaluation of ciprofloxacin HCl - Indion 414 complex

EXPERIMENTAL

Materials and methods:

Ciprofloxacin HCl (gift sample from Darvin pvt.ltd)

Indion 414 (gift sample from Ion Exchange India Limited)

HCl (Finar Chemicals limited, Ahmedabad)

KOH (Hipure fine chem industries, Chennai)

6.2.1 Preparation of ciprofloxacin HCl - Indion 414 complex

Drug resin complexes (DRC) were prepared by using batch process. Accurately

weighed amount of Indion 414 dispersed in a beaker containing deionized water and

allowed to swell for 30 minutes. Swelled resin slurry was filtered on what man filter

paper. Then it was washed with deionized water and then activated with 1 N HCl. The

acid activated resin was rewashed with water until neutral pH was reached. Drug resin

complex (DRC) was prepared, by placing acid activated resin in a beaker containing

deionized water. Accurately weighed amount of ciprofloxacin HCl was added slowly to

the resin slurry and stirred for 3hours in magnetic stirrer. During stirring, pH of the drug

resin slurry was measured frequently and adjusts to 6.5 by using 0.1 M KOH. After three

hours of stirring, the DRC was separated from dispersion by filtration and washed with

deionized water. DRC was dried at 55°C until it was dry. The dried mass was powdered

and sieved through 60-mesh sieve. Complex was evaluated for taste and drug loading

efficiency.

265

Optimization

Procedures as mentioned in chapter 5.2.1 were follwed for effect of drug-resin

ratio on complex formation, effect of pH on drug loading efficiency, effect of resin

activation on drug loading and effect of stirring time on drug loading.

6.2.2 Evaluation of ciprofloxacin HCl - Indion 414 complex

Procedures as mentioned in chapter 5.2.2 were follwed for DSC, X-ray

diffractometry, SEM, FT-IR Studies, taste evaluation, drug loading efficiency and

dissolution profile. Samples intervals are 5, 10, 15, 20, 25 and 30 minutes in dissolution

studies. The amount of drug present in each sample was determined at 276 nm by UV

spectrophotometer.

Table 6.2.1.1.A: Effect of drug resin ratio Table 6.2.1.1.B: Taste evaluation of on complex formation drug resin complex

*highly bitter, **moderately bitter,

***slightly bitter, ****no bitter

Table 6.2.1.2: Effect of pH on drug loading efficiency

Fig. 6.2.1.2: Effect of pH on drug loading efficiency

020406080

100120

0 2 4 6 8

% D

rug

load

ing

pH

Resin Drug-resin ratio

Bitterness level

Indion 414

1:1

1:2

1:3

**

***

****

Dru-resin ratio

Time (hrs)

Percent ciprofloxacin HCl

loading ( ± s.d., n=3)

1:1

1:2

1:3

3

70.31+1.58

87.46+1.48

96.25+1.21

Drug resin ratio pH


loading

( ± s.d., n=3)

1:3

3.0

4.0

5.0

6.0

6.5

7.0

70.12 + 1.34

76.38 + 1.27

83.05 +1.42

89.23 + 1.12

96.25 + 1.21

85.67 +1.47

266

Table 6.2.1.3: Effect of resin activation Table 6.2.1.4: Effect of stirring time on

on drug loading at pH 6.5 drug loading at pH 6.5

(A)

(D)

(C)

(B)

(E)

Temperature (°C)

Fig. 6.2.2.1: DSC Thermograms of (A) Ciprofloxacin HCl, (B) Indion 414,

(C) C-I 414 (1:1), (D) C-I 414 (1:2) and (E) C-I 414 (1:3)

Table 6.2.2.1:

DSC Studies of ciprofloxacin HCl - Indion 414 complex systems

Product

DSC (°C) Fractional crystallinity (% )

Tpeak (°C)

ΔHfusion (J/g)

Ciprofloxacin HCl

C-I 414 (1:1)

C-I 414 (1:2)

C-I 414 (1:3)

152.1

219.6

210.9

220.6

162.9

133.7

129.7

22.9

-

82.07

79.62

14.06

Drug resin ratio

With / without activation

Percent ciprofloxacin HCl loading

( ± s.d., n=3)

1:3

Resin without 1 N HCl

activation

Resin with 1 N HCl

activation

38.37+1.63

96.25+1.21

Drug resin ratio Time (hrs)

Percent norfloxacin loading

( ± s.d., n=3)

1:3

1

2

3

4

79.36 +1.02

90.34+1.53

96.25+1.21

96.62+1.64

267

(A)

(B)

(C)

(D)

(E)

2θ

Fig. 6.2.2.2: X-Ray Diffractograms of (A) Ciprofloxacin HCl, (B) Indion 414,

(C) C-I 414 (1:1), (D) C-I 414 (1:2) and (E) C-I 414 (1:3)

Table 6.2.2.2:

% RDC values from X-ray diffractograms of ciprofloxacin HCl - Indion 414 complexes

Product 2θ % RDC

Ciprofloxacin HCl

C-I 414 (1:1)

C-I 414 (1:2)

C-I 414 (1:3)

26163.56

911.14

0

0

-

3.49

0

0

RDC = Relative degree of crystallinity

(A) (B)

Fig. 6.2.2.3A: SEM Photographs of (A) Ciprofloxacin HCl and (B) Indion 414

(A) (B) (C)

Fig. 6.2.2.3B: SEM Photographs of (A) C-I 414 (1:1), (B) C-I 414 (1:2) and (C) C-I 414 (1:3)

268

(A)

(B)

(C)

(D)

(E)

Wave number (cm-1)

Fig. 6.2.2.4: FTIR Spectras of (A) Ciprofloxacin HCl, (B) Indion 414,

(C) C-I 414 (1:1), (D) C-I 414 (1:2) and (E) C-I 414 (1:3)

Table 6.2.2.5: Taste evaluation of DRC

Resin Drug resin

ratio Bitterness level

Indion 414

1:1

1:2

1:3

**

***

**** *highly bitter, **moderately bitter,***slightly bitter, ****no bitter

Table 6.2.2.6: Drug loading efficiency for DRC

Drug resin ratio Time (hrs)

Percent Ciprofloxacin HCl

Loading ( ± s.d., n=3)

1:3 3 96.25+1.21

269

Table 6.2.2.7:

Dissolution profiles of ciprofloxacin HCl - Indion 414 complex in 0.1 N HCl

Fig. 6.2.2.7.A: Dissolution profiles of Fig. 6.2.2.7.B: First order dissolution plots

ciprofloxacin HCl - Indion 414 complex of ciprofloxacin HCl - Indion 414

in 0.1 N HCl complex in 0.1 N HCl

Fig. 6.2.2.7.C: Hixson-crowell’s dissolution plots of

ciprofloxacin HCl - Indion 414 resin complex in 0.1 N HCl

020406080

100120

0 10 20 30 40

% D

rug

rele

ased

Time (min)

y = -0.060x + 1.960R² = 0.956

-0.50

0.000.501.001.50

2.002.50

0 20 40Log

% d

rug

unre

leas

ed

Time (min)

y = 0.107x + 0.537R² = 0.933

01

2

3

4

56

0 20 40

W0

1/3-

Wt 1

/3

Time (min)

Time (min)

% Nofloxacin dissolved ( ± s.d., n=3)

0

5

10

15

20

25

30

DE10(%)

DE20(%)

T50(min)

K1(min-1)

r

*KH(mg1/3

.min-1

)

0

70.04 ± 1.04

78.48 ± 1.16

84.67± 0.74

92.59 ± 1.48

96.45 ± 0.78

99.12 ± 0.68

54.64

69.87

4.97

0.1396

0.9779

0.1074

270

Table 6.2.2.8: Correlation coefficient (r) values in the analysis of dissolution data as

per first order and Hixson-Crowell’s cube root models

Drug resin complex (DRC)

Correlation Coefficient (r) First order

Hixson-Crowell’s

Ciprofloxacin HCl – Indion 414 (1:3)

0.9779

0.9659

Results and discussion

Optimization of ciprofloxacin HCl - Indion 414 complexation

Ciprofloxacin HCl is a broad spectrum antibiotic, prescribed extensively in both

solid and liquid dosage forms and is extremely bitter, resulting in poor pediatric patient

compliance. Complexation with ion exchange resin is a simple and efficient technique for

masking the bitterness. The drug being solubilized in 0.1 N HCl has desired ionization

power. Indion 414 is highly porous and even though insoluble in water, it is capable of

hydration. Drug loading capacity of Indion 414 is a function of exchange of H+ ions in

the resin with ions in the solution.

Effect of drug-resin ratio on complex formation

Drug resin complexes (DRC) of ciprofloxacin HCl and Indion 414 in 1:1, 1:2 and

1:3 ratios were prepared by using batch process. The DRC systems prepared are listed in

Table 6.2.1.1.A along with their ciprofloxacin HCl contents. There was no significant

loss of drug during the preparation of drug resin complexes in 1:3 ratio and its taste

masking ability was better when compared to other proportions. Hence 1:3 ratio was used

for further studies.

271

Effect of pH on drug loading efficiency

Ciprofloxacin HCl - Indion 414 complexation involves the exchange of ionizable

drug and H+ ions in resin, which in turn depends on the pKa of drug and resin. Such a

mode of complexation between amino groups of ciprofloxacin HCl and –COO-K+

functionality of Indion 414 can be affected by the pH of the reactive media. As shown in

the Table 6.2.1.2 complexation was enhanced with increasing pH from 3 to 6.5. A

maximum percentage of drug loading was obtained at pH 6.5. Above pH 6.5, the

percentage of drug loading was decreased. The pH of the solution affects both solubility

and the degree of ionization of drug and resin. The decreased complexation at lower pH

is due to excess H+ ions in the solution, which have more binding affinity to the –COO-

groups of resin and compete with the drug for binding.

Effect of acid activation on drug loading

The percentage drug loading of acid activated resin and without acid activated

resin at pH 6.5 was given in Table 6.2.1.3. In inactivated resin matrix, the exchangeable

groups are latent and coiled towards the back bone, hence less drug loading efficiency.

The resin activation exposed the exchangeable groups producing rapid drug exchange

and hence higher drug binding.

Effect of stirring time on drug loading

The percentage drug loading with a stirring time of 1 to 4 hours was given in

Table 6.2.1.4. The percentage of the drug loading is increasing with the stirring time up

to three hours. After three hours of stirring, it was observed that, there was no significant

change in percentage of the drug loading. It indicates three hours contact time between

drug and resin is optimimum to equilibrate the ion exchange process to achieve

272

maximum drug loading. This study indicated that optimum ion exchange could be

completed in a period of three hours.

Evaluation of ciprofloxacin HCl - Indion 414 complex

Differential scanning calorimetry

DSC was used to characterize the drug resin complexes (DRC) prepared with

ciprofloxacin HCl and Indion 414. The DSC thermograms of various products are shown

in Fig. 6.2.2.1 and fractional crystallinity [(ΔHf) sample / (ΔHf) crystal] values are given

in Table 6.2.2.1. The DSC curve of pure ciprofloxacin HCl exhibits a two merged broad

endothermic peaks at 152.1°C and 165.7 °C. Indion 414 showed two broad endothermic

peaks at 104.5°C and 294.1°C. In the thermograms of ciprofloxacin HCl - Indion 414

complexes (Fig. 6.2.2.1 C, D & E) the intensity (or height) of the merged endothermic

peak at 152.1°C and 165.7 °C was reduced &sifted in between 210.9°C to 220.6°C and

showed a single endothermic peak indicating interaction of ciprofloxacin HCl with

Indion 414. With ciprofloxacin HCl - Indion 414 complexes (Fig. 6.2.2.1) the

endothermic peak at 152.1°C and 165.7 °C was markedly reduced in DRC 1:3 systems

indicating the absence of crystalline drug and its complete complexation with resin. The

crystallinity level is obtained by measuring the enthalpy of fusion for a sample (ΔHf) and

comparing it to the enthalpy of fusion for the fully crystalline material (ΔHf) crystal.

X-ray diffractometry

Powdered X-ray diffraction patterns of ciprofloxacin HCl and its drug resin

complexes (DRC) with Indion 414 are shown in Fig. 6.2.2.2. XRD of ciprofloxacin HCl

exhibited characteristic diffraction peaks at 8.46°, 9.30°, 19.11°, 19.56°, 20.02°, 23.41°,

24.97°, 26.23°, 26.71, 27.17, 29.44 and 29.73 ° indicating its crystalline nature. Where as

a hollow pattern was recorded for Indion 414 indicating it amorphous state. Crystallinity

273

can be determined by comparing some representative peak heights in the diffraction

patterns of the drug resin complex (DRC) with those of a reference. The relationship used

for the calculation of crystallinity was relative degree of crystallinity (RDC).

RDC= Isam / Iref,

Where Isam is the peak height of the sample under investigation and Iref is the peak

height at the same angle for the reference with the highest intensity (Ryan, 1986)16.

XRD patterns of ciprofloxacin HCl and its drug resin complexes with Indion 414

are shown in Fig. 6.2.2.2. The diffraction peaks were much reduced in the case of C-I 414

(1:1) & C-I 414 (1:2) and were absent in the case of C-I 414 (1:3) respectively. The

disappearance of ciprofloxacin HCl crystalline peaks confirmed the stronger drug

amorphization. Pure drug peak at 9.30◦ (2θ) was used for calculating RDC of drug resin

complex are shown in Table 6.2.2.2. The RDC values of the complexes were less than

those of the drug in all cases and can be arranged in the following order: C-I 414 (1:1) >

C-I 414 (1:2) > C-I 414 (1:3). Furthermore, a reduced number of signals were noticeable

in the complexes, of remarkably lowered intensity, indicating a greater amorphousness of

the drug resin complexes (DRC), compared to the free molecules.

Scanning electron microscopy

Scanning electron microscopy was used to study the microscopic crystal

characters for ciprofloxacin HCl, Indion 414 and their drug resin complexes. The SEM

photographs of various products are shown in Figs. 6.2.2.3A and 6.2.2.3B. SEM of

ciprofloxacin HCl showed paddy husk shaped crystals. The SEM of Indion 414 showed

irregular and uneven gravel shaped particles of various sizes. Morsel particles of irregular

and uneven shaped are adhered on to the surfaces of the larger particles. Fig. 6.2.2.3B

274

shows the SEM of ciprofloxacin HCl - Indion 414 complexes. In the SEM of all drug

resin complex systems, the crystalline characters of ciprofloxacin HCl were absent. As

the proportion of Indion 414 increases in the complex, the gravel particles are seen more

with number of specks adhered on those. The particles in all the systems were irregular

in shape. These microscopic observations indicated a good physical interaction of drug

particles with Indion 414. Although SEM technique is inadequate to conclude complex

formation, the SEM micrographs support the formation of DRC entrapping the drug

particles.

Fourier transform infrared (FT-IR) studies

The FT-IR spectra of ciprofloxacin HCl and its different drug resin complex

systems are shown in Fig. 6.2.2.4. The band at 3377.60 cm-1 of ciprofloxacin HCl spectra

suggested the NH stretching vibration in a secondary amine, which was shifted to

3433.38 cm-1 in optimized drug resin complex prepared with 1:3 ratio of ciprofloxacin

HCl and Indion 414.The peaks appeared at 1624.73 cm-1 and 1384.03cm-1 were shifted to

1690.48 cm-1 and 1398.04 cm-1 assigned to the c=o and c-o group of carboxylic acid

respectively. In addition, an absorption band at 1025.11 cm-1 was assigned to C-F group

was shifted to 1033.42 cm-1. The peak at 943.99 cm-1 assigned to the NH bending of

amine was shifted to 932.92 cm-1. This indicates that there would be a possibility of

chemical modification in the DRC without any changes in basic nucleus of the drug.

Taste evaluation

The taste masking efficiency of resin was evaluated by bitterness level of

DRC.The bitterness level was divided in to four different categories like highly bitter,

moderately bitter, slightly bitter and no bitter. Taste evaluation of DRC in healthy human

275

volunteers confirmed that the taste of ciprofloxacin HCl was successfully masked by

complexing it with Indion 414 at 1:3 ratio. All the volunteers reported that DRC (1:3)

was tasteless and agreeable for a period of 10 minutes. Results are given in Table 6.2.2.5.

Dissolution profiles of ciprofloxacin HCl - Indion 414 complex in 0.1 NHCl

The dissolution rate of ciprofloxacin HCl from DRC complex system (1:3) was

studied using 0.1 N HCl as the dissolution fluid. The results are given in Table 6.2.2.7

and are shown in Figs. 6.2.2.7A, 6.2.2.7B & 6.2.2.7C. The dissolution data were fitted

into various mathematical models such as zero order, first order and Hixson-Crowell’s

cube root models to assess the kinetics and mechanism of dissolution. The dissolution

data obeyed first order kinetic model as well as Hixson-Crowell’s cube root model. The

correlation coefficient (r) value observed in the analysis of dissolution data as per the

above two models are given in Table 6.2.2.8. The correlation coefficient (r) is greater

than 0.910 indicating that the dissolution of ciprofloxacin HCl from ciprofloxacin HCl -

Indion 414 complex obeyed both first order and Hixson-Crowell’s cube root models.

SUMMARY

Drug resin complexes (DRCs) of ciprofloxacin HCl - Indion 414 in 1:1,

1:2 and 1:3 ratios were prepared. The effects of drug-resin ratio, pH, resin activation and

stirring time on complex formation were evaluated. There was no significant loss of drug

during the preparation of drug resin complexes in 1:3 ratio and its taste masking ability

was better when compared to other proportions. Hence 1:3 ratio was used for further

studies. Drug resin complexation was enhanced with increasing pH from 3 to 6.5. A


percentage of drug loading was decreased. The decreased complexation at lower pH is

276

due to excess H+ ions in the solution, which have more binding affinity to the –COO-

groups of resin and compete with the drug for binding. The percentage of drug loading

efficiency of acid activated resin was more compared to inactivated resin. In inactivated

resin matrix, the exchangeable groups are latent and coiled towards the back bone, hence

less drug loading efficiency. The resin activation exposed the exchangeable groups

producing rapid drug exchange and hence higher drug binding. The percentage of the

drug loading was increasing with the stirring time up to three hours. After three hours of

stirring there was no significant increase in percentage of drug loading. It indicates three

hours contact time between drug and resin is optimimum to equilibrate the ion exchange

process to achieve maximum drug loading. Dissolution rate and dissolution efficiency

were evaluated for 1:3 ratio.

DSC and XRD indicated better drug inclusion in DRC. A stronger drug

amorphization and entrapment in DRC was observed. SEM studies indicated good

physical interaction of drug particles with Indion 414. The crystalline character of the

drug was lost and the components of the system (i.e., drug and resin) could not be

differentiated. In FT-IR studies, the band at 3377.60 cm-1 of ciprofloxacin HCl spectra



HCl and Indion 414.The peaks appeared at 1624.73 cm-1 and 1384.03cm-1 were shifted to

1690.48 cm-1 and 1398.04 cm-1 assigned to the c=o and c-o group of carboxylic acid

respectively. In addition, an absorption band at 1025.11 cm-1 was assigned to C-F group

was shifted to 1033.42 cm-1. The peak at 943.99 cm-1 assigned to the NH bending of

277

amine was shifted to 932.92 cm-1. This indicates that there would be a possibility of

chemical modification in the DRC without any changes in basic nucleus of the drug.

6.3 Formulation and in vitro evaluation of ciprofloxacin HCl orally disintegrating

tablets

6.3.1 Formulation of ciprofloxacin HCl orally disintegrating tablets

Materials and methods

Ciprofloxacin HCl - Indion 414 complex (DRC)

Mannitol (Cargill, Germany)

Povidone (Sisco research laboratories, Mumbai)

Sodium starch glycolate (Kemphasol)

Crospovidone (Ozone international, Mumbai)

Aspartame (Cadila pharma, Ahmedabad)

Menthol (SD fine chem. Ltd, Mumbai)

Talc (Otto chemicals)

Magnesium stearate (Laboratory rasayan, SD fine chmicalslimited, Mumbai)

All materials used were of pharmacopoeial grades.

Formulation of ciprofloxacin HCl orally disintegrating tablets by using

superdisintegrants

Ciprofloxacin HCl orally disintegrating tablets were prepared by direct compression

method. According to the formula given in Table 6.3.1, all the ingredients were passed

through 40-mesh sieve separately and collected. The DRC containing amount equivalent

to 100 mg of ciprofloxacin HCl was mixed with the other excipients and compressed into

278

tablets, after lubrication with magnesium stearate, and talc by using 16 station rotary

tablet compression machine equipped with 10 mm flat faced punches. The tablet weight

was adjusted to 600 mg.

Table 6.3.1:

Formulation of ciprofloxacin HCl ODTs prepared by direct compression method

6.3.1.1 Evaluation of granules

Pre compression parameters

Angle of repose, bulk density, compressibility index and Hausner’s ratio are

evaluated as procedure mentioned in chapter 5.3.1.1.

6.3.2 Evaluation of tablets

Hardness, thickness, friability, weight variation test, wetting time, drug content

estimation, in vitro disintegration time, in vitro dissolution studies, taste evaluation,

mouth feel, wetting time and water absorption ratio are evaluated as procedure mentioned

Ingredients mg/tab

Formulation

CRT01 (mg)

CRT02 (mg)

CRT03 (mg)

CRT04 (mg)

CRT05 (mg)

DRC

Mannitol

Povidone

Sodium starch glycolate

Crosspovodine

Aspartame

Menthol

Talc

Magnesium stearate

Total weight (mg)

416

63

36

44

---

24 5 6 6

600

416

63

36

---

44

24 5 6 6

600

416

51

36

28

28

24 5 6 6

600

416

55

36

---

52

24 5 6 6

600

416

47

36

---

60

24 5 6 6

600

279

in chapter 5.3.2. Sampling intervals are 5, 10, 15, 20, 25, 30, 40 and 50 minutes in

dissolution studies. The amount of drug present in each sample was determined at 276

nm by UV spectrophotometer.

Table 6.3.1.1: Evaluation of precompression parameters of granules

Formulation

Angle of repose (θ) *

Bulk density (gm/cm3) *

Tapped density

(gm/cm3) *

Compressibility index (%)

Hausner’s ratio

CRT01

CRT02

CRT03

CRT04

CRT05

28.6±0.04

28.4±0.03

28.2±0.03

28. 3±0.04

28.3±0.04

0.83±0.03

0.81±0.03

0.82±0.04

0.83±0.02

0.82±0.04

0.93±0.03

0.91±0.03

0.92±0.02

0.93±0.04

0.92±0.03

12.05

12.35

12.20

12.05

12.20

1.120

1.123

1.122

1.120

1.122 *All values are expressed as mean ± SE, n=3.

Table 6.3.2.A: Evaluation of postcompression parameters of ciprofloxacin HCl ODTs

*All values are expressed as mean ± SE, n=5; **All values are expressed as mean ± SE, n=10; ***All values are expressed as mean ± SE, n=20.

Fig. 6.3.2.A: Comparison of disintegration time for ciprofloxacin HCl ODTs of different

superdisintegrants

7.33% SSG 58

7.33% CPV63 4.67% SSG

4.67% CPV32 8.67% CPV

23 10% CPV 16

0

20

40

60

80

CRT01 CRT02 CRT03 CRT04 CRT05

Disi

nteg

ratio

n tim

e (s

ec)

Formuation

Thickness (mm)*

Hardness (Kg/cm2)*

Friability (%)**

Weight variation (mg) ***

Drug content (%)**

Disintegration

time (sec)*

Wetting time

(sec)*

Water absortion

ratio

CRT01

CRT02

CRT03

CRT04

CRT05

4.56±0.04

4.57±0.03

4.56±0.02

4.57±0.02

4.56±0.03

4.3±0.56

4.4±0.47

4.2±0.42

4.4±0.52

4.3±0.68

0.28±0.08

0.22±0.08

0.19±0.09

0.24±0.06

0.22±0.07

1.4±0.46

1.5±0.72

1.5±0.39

1.4±0.58

1.4±0.61

99.20±1.43

98.75±1.21

98.69±1.54

99.05±0.97

99.39±1.31

58±7

63±5

32±4

23±4

16±3

53±6

59±5

30±5

20±3

14±3

040±0.04

0.39±0.03

0.42±0.02

0.42±0.03

0.43±0.03

280

Table 6.3.2.B: In vitro dissolution studies of Ciprofloxacin HCl ODTs

Fig. 6.3.2.B1: Dissolution profiles of Fig. 6.3.2.B2: First order Dissolution plots

Ciprofloxacin HCl ODTs containing of Ciprofloxacin HCl ODTs containing drug

drug as drug resin complexes and as drug resin complexes and

superdisintegrants superdisintegrants

0

20

40

60

80

100

120

0 20 40 60

% D

rug

rele

ase

Time (min)CRT01 CRT02 CRT03CRT04 CRT05

0.00

0.50

1.00

1.50

2.00

2.50

0 20 40 60

Log%

dru

g un

rele

ased

Time (min)


Time (min)

Cumulative % of drug release


0 5

10

15

20

25

30

40

50

DE10 (%)

DE20 (%)

T50 (min)

K1 (min-1) r

0

60.14+1.37

64.58+1.34

69.34+1.54

75.94+0.74

85.12+1.12

89.79+0.47

94.67+1.04

98.79+0.82

46.22

58.01

8.96

0.08

0.9781

0

64.89+1.25

68.32+1.53

73.56+1.43

79.23+1.78

88.22+2.05

92.68+1.52

96.85+0.79

99.07+0.48

49.53

61.60

8.15

0.0850

0.9853

0

67.89+1.62

72.68+1.84

80.83+2.21

88.72+1.31

93.78+1.58

96.93+0.76

99.05+0.68

---

52.12

66.44

6.36

0.1089

0.9903

0

73.04+2.41

80.74+1.38

86.35+0.94

93.37+1.22

96.83+0.74

99.24+0.61

---

---

56.71

71.70

4.85

0.1428

0.9772

0

74.79+1.43

81.36+0.85

88.02+1.47

95.32+1.63

97.12+1.32

99.45+0.75

---

---

57.74

72.96

4.55

0.1525

0.9774

281

Table 6.3.2.C: Taste evaluation

*highly bitter, **moderately bitter, ***slightly bitter, ****no bitter


In the present study, water insoluble diluents such as microcrystalline cellulose

and dicalcium phosphate and L-HPC were omitted from the study as they are expected to

cause an unacceptable feeling of grittiness in the mouth. Among the soluble diluents,

mannitol was selected as model soluble diluent considering its advantages in terms of

easy availability, cost-effectiveness, negative heat of dissolution and relative moisture

insensitivity. For each designed orally disintegrating tablet formulation, blend of drug in

a drug resin complex form [Ciprofloxacin HCl: Indion414; (1:3)] and excipients with

different concentrations of super disintegrating agents, was prepared and evaluated for

precompression properties. Results are shown in Table 6.3.1.1. Bulk density was found to

be between 0.81±0.03 to 0.83±0.03 gm/cm3 and tapped density between 0.91±0.03 to

0.93±0.04 gm/cm3 for all formulations. From the density data, % compressibility was

calculated and was found to be between12.05 to 12.35. Angle of repose was found to be

in the range of 28.2±0.03 to 28.6±0.04. Hausner’s ratio was found to be below 1.120 to

1.123. All the formulations show parameters that are within prescribed limits and

indicated good flow property. Hence tablets were prepared by using direct compression

technique.

Formulation Bitterness

level

CRT01

CRT02

CRT03

CRT04

CRT05

****

****

****

****

****

282

The data obtained, of post compression parameters such as thickness, hardness,

friability, weight variation, uniformity of content, disintegration time, wetting time and

water absortion ratio are shown in Table 6.3.2.A. Thickness was found to be in range of

4.56±0.04 to 4.57 ±0.03 mm in all formulations. The hardness was found to be in range

of 4 to 5 kg/cm2 in all the formulations indicating good mechanical strength with an

ability to withstand physical and mechanical stress conditions while handling. In all the

formulations, the friability value is less than 1%. All the tablets passed weight variation

test as the % weight variation was within the Pharmacopoeial limits. The weight of all the

tablets was found to be uniform, with low standard deviation values indicating efficient

mixing of drug, superdisintegrants and excipients. The percentage drug content of all the

tablets was found to be between 98.69 ± 1.54 and 99.39 ±1.31 % of ciprofloxacin HCl,

which was within the acceptable limits. The results of in vitro disintegration of all the

tablets were found to be within the prescribed limits and satisfying the criteria of fast

dissolving tablets. Formulations containing crosspovidone, disintegrated faster when

compared to other formulations containing sodium starch glycolate. The disintegration

time in relation to super disintegrants concentration is shown in Fig. 6.3.2.A, reflecting

that the higher the concentration rapid will be the disintegration. The disintegration time

for each tablet was found to be less than one and half minute and the tablets containing

crosspovidine (10%; CRT05) showed lowest disintegration time (16±3 sec). The lowest

wetting time (14±3 sec) and highest water absorption ratio (0.43±0.03) was obtained with

formulation CRT05. The faster disintegration of superdisintegrants can be attributed to

the increase in the rate and extent of water uptake and consequent swelling and increased

hydrodynamic pressure to induce complete disintegration.

283

The results of in vitro dissolution studies of various formulations, CRT01 to

CRT05, in 0.1 N HCl, are shown in Table 6.3.2.B and in Figs. 6.3.2.B1 & 6.3.2.B2. All

the release profiles showed two different phases of drug release. An initial rapid release

phase is followed by a slower release phase. These results could be attributed to the

general phenomenon of particle size reduction during dissolution process. In the presence

of disintegrants, the matrix might be distorted, resulting in higher surface area, allowing

the superdisintegrants to readily pick up water and thereby cause a rapid rate of

dissolution. The concentration of superdisintegrants in the formulation also affected the

dissolution rate. In vitro dissolution rate of orally disintegrating tablets of ciprofloxacin

HCl increased with increase in concentration of super disintegrants. Tablets formulated

with10% w/w of crosspovidone, showed better dissolution rate among all other

formulations. The dissolution of ciprofloxacin HCl from all the tablets followed first

order kinetics. Plots of log % drug remained vs time were found to be linear. The

dissolution kinetic data is given in Table 6.3.2.B. Among all the formulations CRT05

which contain 10% of crosspovidone gave the highest dissolution (99.45 %) at the end of

30 minutes. The dissolution rate constant (K1), half-life, DE10 % and DE20 % for

formulation CRT05 (10% crosspovidone) were 0.1525 min-1, 4.55 minutes, 57.74 and

72.96% respectively.

A panel of selected healthy human volunteers evaluated the orally disintegrating

tablets for taste masking. None of the formulation show any bitter taste for a period of 10

minutes when tablets are evaluated as procedure mentioned in chapter 6.1.3, which shows

excellent taste masking effect of the drug resin complex [Ciprofloxacin HCl: Indion 414;

(1:3)]. The healthy human volunteers participated in taste evaluation test were asked to

284

give their opinion about the feeling of smoothness or grittiness of the dispersion soon

after held in mouth. All the formulations showed smooth and pleasant mouth feeling, thus

fulfill the requirements of orally disintegrating tablets.

SUMMARY AND CONCLUSION




masking the bitterness. The basic method considered for the development of taste masked

ciprofloxacin HCl orally disintegrating tablets is the direct compression method by using

mannitol as diluent and sodium starch glycolate (SSG) & crospovidone (CPV) as

superdisintegranting agents at four concentrations (4.67, 7.33, 8.67 and 10%) with the

drug in a drug resin complex form (Ciprofloxacin HCl: Indion 414; 1:3 ratio). Based on

the disintegration time and wetting time, superdisintegrants can be ranked as

crospovidone (CPV) > sodium starch glycolate (SSG). All prepared tablets were

evaluated for weight variation, friability, hardness, disintegration time, drug content,

taste, mouth feel, wetting time and dissolution rate. Disintegration time and wetting time

of orally disintegrating tablets of ciprofloxacin HCl decreased with increase in

concentration of super disintegrants and is found to be less for tablets formulated using

10 % w/w crosspovidone. The dissolution of drug followed first order kinetics in all

formulations. Tablets formulated with 10% w/w of crosspovidone, showed better

dissolution rate among all other formulations. May be exhibiting these result due to the

concentration used and swelling property of crosspovidone. Thus the technique of

285

preparation of DRC of ciprofloxacin HCl with Indion 414 gave ODTs of pharmacopeial

quality, pediatric patient palatability, fast acting, convenient and inexpensive.

6.4 Formulation and evaluation of ciprofloxacin HCl dry syrup

6.4.1 Formulation of ciprofloxacin HCl dry syrup


Materials Ciprofloxacin HCl - Indion 414 complex (DRC) Ciprofloxacin HCl (gift sample from Darvin pvt.ltd) Sodium citrate (Qualigens fine chemicals) Citric acid (Otto kemi, Mumbai) Lutrol F 68 (gift sample from BASF) Sorbitol (gift sample from Cargill, Germany) Erythritol (gift sample from Cargill, Germany) Aspartame (Cadila pharma, Ahmedabad) Sodium benzoate (Qualigens fine chemicals) Xanthan gum (Kemphasol, Mumbai) Sodium carboxymethyl cellulose (Central Drug House laboratory reagents) Orange flavor (PAN Aroma Madras Pvt.Ltd, Chennai) Methods

Drug resin complex and other ingredients were passed through 60-mesh sieve and

collected individually. According to the formula given in Table 6.4.1, all ingredients were

accurately weighed and blended homogeneously. This homogeneous dry syrup was filled

in to an amber colored bottle and stored in a dry place at room temperature.

286

Table 6.4.1: Formulation of ciprofloxacin HCl dry syrups

6.4.2 Evaluation of dry syrup

Sedimentation volume, pH, specific gravity, drug content, taste evaluation, mouth

feel and in vitro dissolution studies are evaluated as procedure mentioned in chapter

5.4.2. Sampling intervals are 5, 10, 15, 20, 25 and 30 minutes in dissolution studies. The

amount of drug present in each sample was determined at 276 nm by UV

spectrophotometer.

Ingredients / 5 ml

Formulation

CRDS01

(mg)

CRDS02

(mg)

CRDS03

(mg)

CRDS04

(mg)

CRDS05

(mg)

Drug/DRC

Sodium citrate

Citric acid

Lutrol F 68

Sorbitol

Erythroitol

Aspartame

Sodium benzoate

Xanthan gum

Sodium carboxymethyl Cellulose

Orange flavour

100

72

72 5

2200

---

---

0.4

---

---

qs

416

72

72

30

2200

---

---

0.4

150

---

qs

416

70

70

30

---

2200

55

0.4

120

---

qs

416

74

74

30

---

2200

65

0.4

100

---

qs

416

74

74

30

---

2200

65

0.4

---

100

qs

287

Table 6.4.2.A: Evaluation of physical properties of reconstituted dry syrups

Table 6.4.2.B: Taste evaluation of reconstituted dry syrups Formulation Bitterness

level CRDS01

CRDSO2

CRDSO3

CRDSO4

CRDSO5

*

***

***

****

**** *highly bitter, **moderately bitter, ***slightly bitter, ****no bitter

Formula tion

Sedimentation volume (%) at 25 oC

( ± s.d., n=3)

pH of the formulation at 25o

C

( ± s.d., n=3)

Specific gravity at 25oC

( ± s.d., n=3) Drug content (%)

( ± s.d., n=3)

Day- 1 Day- 7 Day- 1 Day- 7 Day- 1 Day- 7 Day- 1 Day- 7 CRDSO2 CRDSO3 CRDSO4 CRDSO5

99.4+0.36 91.8+0.75 79.5+1.2 71.2+1.03

99.4+0.42 90.3+0.84 77.8+0.83 66.7+0.74

4.50+0.04 4.48+0.03 4.42+0.03 5.54+0.03

4.32+0.03 4.53+0.04 4.52+0.03 5.52+0.04

1.15+0.04 1.14+0.03 1.13+0.04 1.13+0.04

1.17+0.04 1.16+0.03 1.15+0.04 1.16+0.04

96.03+1.23 97.74+1.12 98.67+1.34 98.82+0.45

95.34+1.46 96.23+1.35 97.31+0.84 97.32+0.74

288

Table 6.4.2.C.1:

In vitro dissolution studies of ciprofloxacin HCl reconstituted dry syrups on day 1

Fig. 6.4.2.C.1A: Dissolution profiles of Fig. 6.4.2.C.1B: First order dissolution plots of

ciprofloxacin HCl reconstituted dry syrups ciprofloxacin HCl reconstituted dry syrups

containing drug as drug resin complexes containing drug as drug resin complexes

on day 1 on day 1

0

20

4060

80

100120

0 10 20 30 40

% D

rug

rele

ase

Time (min)CRDS02 CRDS03CRDS04 CRDS05

0.000.501.001.502.002.50

0 10 20 30 40

Log%

dru

g un

rele

ased

Time (min)CRDS02 CRDS03 CRDS04 CRDS05

Time (min)

Cumulative % of drug release ( ± s.d., n=3)

CRDS02 CRDS03 CRDS04 CRDS05 0 5

10

15

20

25

30

DE10 (%)

DE15 (%)

T50 (min)

K1(min-1) r

0

74.13+1.22

78.42+0.84

86.85+0.75

93.29+1.31

97.65+1.46

99.12+0.64

56.67

65.28

4.81

0.1442

0.9824

0

78.43+1.32

86.32+1.04

93.13+1.16

97.71+1.42

99.23+0.74

---

60.80

70.44

3.82

0.1815

0.9897

0

82.56+0.97

90.05+1.35

97.18+1.42

99.39+0.74

---

---

63.79

73.73

2.88

0.2404

0.9900

0

83.04+1.23

90.89+0.85

98.32+1.38

99.64+0.76

---

---

64.24

74.36

2.55

0.2713

0.9921

289

Table 6.4.2.C.2:


Fig. 6.4.2.C.2A: Dissolution profiles of Fig. 6.4.2.C.2B: First order Dissolution plots of



on day 7 on day 7

0

20

40

60

80

100

120

0 10 20 30 40

% D

rug

rele

ase

Time (min)CRDS02 CRDS03CRDS04 CRDS05

0.00

0.50

1.00

1.50

2.00

2.50

0 10 20 30 40

Log%

dru

g un

rele

ased

Time (min)CRDS02 CRDS03 CRDS04 CRDS05

Time (min)


CRDS02 CRDS03 CRDS04 CRDS05 0 5

10

15

20

25

30

DE10 (%)

DE15 (%)

T50 (min)

K1(min-1) r

0

73.05+1.06

77.34+1.35

84.78+1.29

91.63+1.53

95.08+1.47

97.04+0.88

55.86

64.26

6.49

0.1069

0.9808

0

76.24+1.47

84.75+1.25

91.39+1.64

96.17+1.37

97.06+0.78

---

59.31

68.90

5.12

0.1354

0.9761

0

80.41+1.27

87.87+1.02

95.45+1.26

97.43+0.73

---

---

62.17

72.00

3.94

0.1757

0.9789

0

81.75+1.44

88.96+1.30

96.58+1.21

97.64+0.75

---

---

63.12

79.03

3.78

0.1833

0.9738

290


For each designated dry syrup formulation, blend of drug in a drug resin complex

form [Ciprofloxacin HCl: Indion414; (1:3)] and excipients with different concentrations

of suspending agents, was prepared. In the CRDS01 formulation, pure drug was

formulated with 22 times of sorbitol. There was no significant change in the masking of

bitter taste of the drug with 22 times of sorbitol. Hence DRC [Ciprofloxacin HCl: Indion

414 (1:3) complex) was used instead of pure drug for formulations CRDS02 to CRDS05.

Various concentrations of suspending agents were added to formulations CRDS02 to

CRDS05. After reconstitution, each dry syrup formulation was evaluated for

sedimentation volume, pH, specific gravity, drug content and taste on day 1 & day 7.

Results are shown in Tables 6.4.2.A and 6.4.2.B. Percentage sedimentation volume was

found to be between 71.2+1.03 to 99.4+0.36 on day 1and 66.7+0.74 to 99.4+0.42 on day

7. Each sample of the formulation had good visual appearance and high sedimentation

volume, which indicates that the DRC formed flocs.

There was no drastic change in the pH of reconstituted dry syrup from day 1 to

day 7. The pH of the formulation greatly influences the drug release which in turns

affects the bitterness of the syrup. All the formulations had the pH of above 4.42+0.03 to

below5.54+0.03 and 4.32+0.04 to 5.52+0.04 on day 1 and day 7 respectively. Specific

gravity of the reconstituted syrup was found to be in the range of 1.13+0.04 to 1.15+0.04

& 1.15+0.04 to 1.17+0.04 on day 1 and day 7 respectively. It influences the degree of

sedimentations. As the density of the syrup is high the rate of settlement of particles will

tends to low. The percentage drug content of reconstituted syrup was found to be between

291

96.03+1.23 to 98.82+0.45 & 95.34+1.46 to 97.32+0.74 of ciprofloxacin HCl on day 1

and day 7 respectively, which were within the acceptable limits.

The in vitro dissolution study was carried out with 0.1 N HCl and greater than

75% of the ciprofloxacin HCl was released at the end of 10 minutes on day 1 & day 7.

The results of in vitro dissolution studies of various formulations, CRDS02 to CRDS05,

in 0.1 N HCl, are shown in Table 6.4.2.C.1 and in Figs. 6.4.2.C.1A & 6.4.2.C.1B on day

1. Day 7 results are shown in Table 6.4.2.C.2 and in Figs. 6.4.2.C.2A & 6.4.2.C.2B. All



general phenomenon of particle size reduction during dissolution process.

The dissolution of ciprofloxacin HCl from reconstituted dry syrup formulations

followed first order kinetics. Plots of log % drug remained vs time were found to be

linear. The dissolution kinetic data are given in Table 6.4.2.C.2 on day 1and in Table

6.4.2.C.2 on day 7. The percentage of drug dissolved from CRDS04 & CRDS05 was to

be more than the other two formulations. CRDS04 has the more sedimentation volume

with ease of redispersibility and comparable drug release profile with CRDS05

formulation. The dissolution rate constant (K1), half-life, DE10% and DE15% for

formulation CRDS04 were 0.2404 min-1, 2.88 minutes, 63.79 and73.73 % respectively on

day 1. On day 7, dissolution rate constant (K1), half-life, DE10% and DE15% for formulation

CRDS04 were 0.1757 min-1, 3.94 minutes, 62.17 and72.00 % respectively.

A panel of healthy human volunteers evaluated the reconstituted dry syrups for

bitter taste masking by procedure mentioned in chapter 6.1.3. CRDS01 was highly bitter

in taste. CRDS02 & CRDS03 moderately bitter and CRDS04 & CRDS05 were no bitter

292

in taste for a period of 10 minutes. The healthy human volunteers participated in taste

evaluation test were asked to give their opinion about the feeling of smoothness or

grittiness of the dispersions soon after held in mouth. CRDS04 & CRDS05 showed

smooth and pleasant mouth feeling.


Complexation of ciprofloxacin HCl with ion exchange resin is a simple and

efficient technique for masking the bitterness of the drug. Dry syrup was prepared by

passing all the ingredients through 60-mesh sieve. Ciprofloxacin HCl dry syrup

formulation was prepared by using sorbitol, erythroitol & aspartame as sweeting agents

and sodium carboxymethyl cellulose & xanthan gum as suspending agents at different

concentrations with the drug in a drug resin complex form [Ciprofloxacin HCl:

Indion414; (1:3)].The formulated dry syrup was evaluated for drug content, taste of the

syrup after reconstitution, pH of the syrup, sedimentation volume, specific gravity and

dissolution characteristics. The sedimentation volume and redispersiblity was more for

the dry syrup containing 3.38% of xanthan gum (CRDS04). The dissolution of the drug

from the reconstituted syrup follows first order kinetics. Thus the technique of

preparation of DRC of ciprofloxacin HCl with Indion 414 gave dry syrup of

pharmacopeial quality, pediatric patient palatability, fast acting, convenient and

inexpensive.

Among all the DRC formulations CRDS04 was found to be better formulation

because of high dissolution rate, taste masking & disintegration. This formulation,

CRDSO4, may be exhibiting these results due to the following reasons.

293

1. Indion 414 has taste masking and super disintegrating characteristics

which result in increased dissolution rate. Indion 254 (strong acid cation

exchanger) bestowed slow drug release to the formulations because it

binds with drug strongly when compared to Indion 414(weak acid cation

exchanger).

2. The concentration and nature of the xanthan gum used in this formulation

CRDS04, impart desirable viscousity, optimum sedimentation volume,

ease of redispersibility and increased dissolution rate when compared to

other liuid formulations.

294

6.5 Preparation and evaluation of ciprofloxacin HCl - Indion 254complex

EXPERIMENTAL

Materials and methods:


Indion 254 (gift sample from Ion Exchange India Limited)

HCl (Finar Chemicals limited, Ahmedabad)

KOH (Hipure fine chem industries, Chennai)

6.5.1 Preparation of ciprofloxacin HCl - Indion 254 complex

Drug resin complexes (DRC) were prepared by using batch process. Accurately

weighed amount of Indion 254 dispersed in a beaker containing deionized water and

allowed to swell for 30 minutes. Swelled resin slurry was filtered on what man filter

paper and then it was washed with deionized water. Drug resin complex (DRC) was

prepared, by placing swelled resin in a beaker containing deionized water. Accurately

weighed amount of ciprofloxacin HCl was added slowly to the resin slurry and stirred for

3hours in magnetic stirrer. During stirring, pH of the drug resin slurry was measured

frequently and adjusts to 6.5 by using 0.1 M KOH. After three hours of stirring, the DRC

was separated from dispersion by filtration and washed with deionized water. DRC was

dried at 55°C until it was dry. The dried mass was powdered and sieved through 60-mesh

sieve. Complex was evaluated for taste and drug loading efficiency.

Optimization

Procedures as mentioned in chapter 5.2.1 were follwed for effect of drug-

resin ratio on complex formation, effect of pH on drug loading efficiency and effect of

stirring time on drug loading with out the resin acid activation. The amount of drug

present in each sample was determined at 276 nm by UV spectrophotometer.

295

6.5.2 Evaluation of ciprofloxacin HCl - Indion 254 complex


diffractometry, SEM, FT-IR Studies, taste evaluation, drug loading efficiency and

dissolution profile. Sampling intervals are 5, 10, 15, 20, 25, 30, 45, 60, 90 and 120

minutes in dissolution studies. The amount of drug present in each sample was

determined at 276 nm by UV spectrophotometer.

Table 6.5.1.1.A: Effect of drug resin ratio on Table 6.5.1.1.B: Taste evaluation of complex formation drug resin complex


Table 6.5.1.2: Effect of pH on

drug loading efficiency

Drug resin ratio

pH

Percent ciprofloxacin HCl loading ( ± s.d., n=3)

Fig. 6.5.1.2: Effect of pH on drug loading efficiency

1:3

3.0 4.0 5.0 6.0 6.5 7.0

52.11 + 2.11 57.04 + 1.43 69.24 +1.68 80.45 + 1.75 83.94+1.35 74.69 +1.51

0

20

40

60

80

100

0 2 4 6 8

% D

rug

load

ing

pH

Resin Drug- resin ratio

Bitterness level

Indion 254

1:1

1:2

1:3

**

***

****

Drug-resin ratio

Time (hrs)



1:1

1:2

1:3

3

57.31+2.12

73.24+1.54

83.94+1.35

296

Table 6.5.1.3: Effect of resin soaking time on Table 6.5.1.4: Effect of stirring time on

drug loading at pH 6.5 drug loading at pH 6.5

(A)

(B)

(C)

(D)

(E)

Temperature (°C)

Fig. 6.5.2.1: DSC Thermograms of (A) Ciprofloxacin HCl, (B) Indion 254,

(C) C-I 254 (1:1), (D) C-I 254 (1:2) and (E) C-I 254 (1:3)

Table 6.5.2.1:DSC Studies of ciprofloxacin HCl - Indion 254 complex Systems

Product DSC (°C) Fractional

crystallinity (% )

Tpeak (°C)

ΔHfusion (J/g)

Ciprofloxacin HCl

C-I 254 (1:1)

C-I 254 (1:2)

C-I 254 (1:3)

152.1

110.5

108.8

---

162.9

74.46

15.53

---

-

45.71

9.53

---

Drug resin ratio

Time (hrs)



1:3

1

2

3

4

69.23 +1.46

79.21+1.38

83.94+1.35

84.45+1.20

Drug resin ratio

Soaking time

( mins)



1:3

10

20

30

40

50.32+1.76

74.21+1.82

83.94+1.35

84.03+1.17

297

(A)

(B)

(C)

(D)

(E)

2θ

Fig. 6.5.2.2: X-Ray Diffractograms of (A) Ciprofloxacin HCl, (B) Indion 254,

(C) C-I 254 (1:1), (D) C-I 254 (1:2) and (E) C-I 254 (1:3)

Table 6.5.2.2:

% RDC values from X-ray diffractograms of ciprofloxacin HCl- Indion 254

complexes Product 2θ % RDC

Ciprofloxacin HCl

C-I 254 (1:1)

C-I 254 (1:2)

C-I 254 (1:3)

26163.56

3098.52

1109.96

141.78

-

11.84

4.24

0.54


298

(A) (B)

Fig. 6.5.2.3A: SEM Photographs of (A) Ciprofloxacin HCl and (B) Indion 254

(A) (B) (C)

Fig. 6.5.2.3B: SEM Photographs of (A) C-I 254 (1:1), (B) C-I 254 (1:2) and

(C) C-I 254 (1:3)

(B)

(C)

(D)

(E)

(A)

Wave number (cm-1)

Fig. 6.5.2.4: FTIR Spectras of (A) Ciprofloxacin HCl, (B) Indion 414,

(C) C-I 254 (1:1), (D) C-I 254 (1:2) and (E) C-I 254 (1:3)

299

Table 6.5.2.5: Taste evaluation of DRC Table 6.5.2.6: Drug loading efficiency for DRC

Resin Drug resin

ratio Bitterness level

Indion 254

1:1

1:2

1:3

**

***

**** *highly bitter, **moderately bitter,

***slightly bitter, ****no bitter

Table 6.5.2.7: Dissolution profiles of

ciprofloxacin HCl - Indion 254 complex in 0.1 N HCl

Drug resin

ratio Time (hrs)



1:3 3 83.94+1.35

Time

(min)

% Nofloxacin dissolved

( ± s.d., n=3)

0

5

10

15

20

25

30

45

60

90

120

DE10 (%)

DE30 (%)

T50(min)

K1(min-1)

r

*KH(mg1/3

.min-1

)

0

37.63 ± 1.41

42.13 ± 1.23

47.75± 0.69

51.76 ± 1.46

55.96 ± 1.29

60.79 ± 0.87

64.33 ± 0.75

70.29± 1.32

79.06 ± 1.43

83.07 ± 1.25

29.35

44.27

61.41

0.0113

0.9901

0.0121

300

Fig. 6.5.2.7.A: Dissolution profiles of Fig. 6.5.2.7.B: First order dissolution plots of

ciprofloxacin HCl - Indion 254 complex ciprofloxacin HCl - Indion 254 complex

in 0.1 N HCl in 0.1 N HCl

Fig. 6.5.2.7.C: Hixson-crowell’s dissolution plots of ciprofloxacin HCl - Indion 254 complex in

0.1 N HCl

Table 6.5.2.8: Correlation coefficient (r) values in the analysis of dissolution data as

per first order and Hixson-Crowell’s cube root models


Optimization of ciprofloxacin HCl - Indion 254 complexation




0

20

40

60

80

100

0 50 100 150

% D

rug

rele

ased

Time (min)

y = -0.004x + 1.784R² = 0.980

0.00

0.40

0.80

1.20

1.60

2.00

0 50 100 150

Log

% d

rug

unre

leas

ed

Time (min)

y = 0.012x + 0.748R² = 0.961

0123

456

0 50 100 150

W0

1/3-

Wt 1

/3

Time (min)

Drug resin complex (DRC)

Correlation coefficient (r) First order

Hixson-Crowell’s

Ciprofloxacin HCl - Indion 254

(1:3)

0.9901

0.9804

301

masking the bitterness. The drug being solubilized in 0.1 N HCl has desired ionization

power. Indion 254 is highly porous and even though insoluble in water, it is capable of

hydration. Drug loading capacity of Indion 254 is a function of exchange of H+ ions in

the resin with ions in the solution.

Effect of drug-resin ratio on complex formation

Drug resin complexes (DRC) of ciprofloxacin HCl and Indion 254 in 1:1, 1:2 and

1:3 ratios were prepared by using batch process. The DRC systems prepared are listed in

Table 6.5.1.1.A along with their ciprofloxacin HCl contents. Drug resin complex in 1:3

ratio is better taste masking ability when compared to other proportions. Hence 1:3 ratio

are used for further studies.

Effect of pH on drug loading efficiency

Ciprofloxacin HCl - Indion 254 complexation involves the exchange of ionizable

drug and metal ions in resin, which in turn depends on the pKa of drug and resin. Such a

mode of complexation between amino groups of ciprofloxacin HCl and –S03-Na+

functionality of Indion 254 can be affected by the pH of the reactive media. As shown in

the Table 6.5.1.2 complexation was enhanced with increasing pH from 3 to 6.5. A


percentage of drug loading was decreased. The pH of the solution affects both solubility

and the degree of ionization of drug and resin. The decreased complexation at lower pH

is due to excess H+ ions in the solution, which have more binding affinity to the coo-

groups of resin and compete with the drug for binding.

Effect of resin soaking time on drug loading at pH 6.5

The effect of resin soaking time on percentage of drug loading was given in Table

6.5.1.3.The percentage of the drug loading is increasing with the soaking time up to 30

302

minutes. After 30 minutes of soaking, it was observed that, there was no significant

change in percentage of the drug loading. It indicates 30 minutes of soaking time could

be optimized to achieve maximum drug loading.The effect of resin soaking time on

percentage drug loading at pH 6.5 was given in Table6.5.1.3. In non soaking resin matrix,

the exchangeable groups are latent and coiled towards the back bone, hence less drug

loading efficiency. The resin soaking exposed the exchangeable groups producing rapid

drug exchange and hence higher drug binding.

Effect of stirring time on drug loading

The percentage drug loading with a stirring time of 1 to 4 hours was given in

Table 6.5.1.4. The percentage of the drug loading is increasing with the stirring time up

to three hours. After three hours of stirring, it was observed that, there was no significant

change in percentage of the drug loading. It indicates three hours contact time between

drug and resin is optimimum to equilibrate the ion exchange process to achieve

maximum drug loading. This study indicated that optimum ion exchange could be

completed in a period of three hours.

Evaluation of ciprofloxacin HCl- Indion 254 complex

Differential scanning calorimetry

DSC was used to characterize the drug resin complexes (DRC) prepared with

ciprofloxacin HCl and Indion 254. The DSC thermograms of various products are shown

in Fig. 6.5.2.1 and fractional crystallinity [(ΔHf) sample / (ΔHf) crystal] values are given

in Table 6.5.2.1. The DSC curve of pure ciprofloxacin HCl exhibits a two merged broad

endothermic peaks at 152.1°C and 165.7 °C. Indion 254 showed broad endothermic

peaks 99.2°C. In the thermograms of ciprofloxacin HCl - Indion 254 complexes (Fig.

303

6.5.2.1 C, D & E) the intensity (or height) of the merged endothermic peak at 152.1°C

and 165.7 °C was reduced &sifted in between 108.8°C & 110.5°C and showed a single

endothermic peak indicating interaction of ciprofloxacin HCl with Indion 254. With

ciprofloxacin HCl - Indion 414 complexes (Fig. 6.2.2.1 ) the endothermic peak at

152.1°C and 165.7 °C was absent in 1:3 DRC systems indicating the absence of

crystalline drug and its complete complexation with resin. The crystallinity level is

obtained by measuring the enthalpy of fusion for a sample (ΔHf) and comparing it to the

enthalpy of fusion for the fully crystalline material (ΔHf) crystal.

X-ray diffractometry

Powdered X-ray diffraction patterns of ciprofloxacin HCl and its drug resin

complexes (DRC) with Indion 254 are shown in Fig. 6.5.2.2. XRD of ciprofloxacin HCl

exhibited characteristic diffraction peaks at 8.46°, 9.30°, 19.11°, 19.56°, 20.02°, 23.41°,

24.97°, 26.23°, 26.71, 27.17, 29.44 and 29.73 ° indicating its crystalline nature. Where as

a hollow pattern was recorded for Indion 254 indicating it amorphous state. Crystallinity

can be determined by comparing some representative peak heights in the diffraction

patterns of the drug resin complex (DRC) with those of a reference. The relationship used

for the calculation of crystallinity was relative degree of crystallinity (RDC).

RDC= Isam / Iref,


height at the same angle for the reference with the highest intensity (Ryan, 1986).

XRD patterns of ciprofloxacin HCl and its drug resin complexes with Indion 254

are shown in Fig. 6.5.2.2. The diffraction peaks were much reduced in the case of C-I 254

(1:1) & C-I 254 (1:2) and were absent in the case of C-I 254 (1:3) respectively. The

304

disappearance of ciprofloxacin HCl crystalline peaks confirmed the stronger drug

amorphization. Pure drug peak at 9.30◦ (2θ) was used for calculating RDC of drug resin

complex are shown in Table 6.5.2.2. The RDC values of the complexes were less than

those of the drug in all cases and can be arranged in the following order: C-I 254 (1:1) >

C-I 254 (1:2) > C-I 254 (1:3). Furthermore, a reduced number of signals were noticeable

in the complexes, of remarkably lowered intensity, indicating a greater amorphousness of

the drug resin complexes (DRC), compared to the free molecules.

Scanning electron microscopy


characters for ciprofloxacin HCl, Indion 254 and their drug resin complexes. The SEM

photographs of various products are shown in Figs. 6.5.2.3A and 6.5.2.3B. SEM of

ciprofloxacin HCl showed paddy husk shaped crystals. The SEM of Indion 254 showed

irregular and unven gravel shaped particles of various sizes. Morsel particles of irregular

and uneven shaped are adhered on to the surfaces of the larger particles. Fig. 6.5.2.3B

shows the SEM of ciprofloxacin HCl - Indion 254 complexes. In the SEM of all drug

resin complex systems, the crystalline characters of ciprofloxacin HCl were absent. As

the proportion of Indion 254 increases in the complex, the gravel particles are seen more

with number of specks adhered on those. The particles in all the systems were irregular

in shape. These microscopic observations indicated a good physical interaction of drug

particles with Indion 254. Although SEM technique is inadequate to conclude complex

formation, the SEM micrographs support the formation of DRC entrapping the drug

particles.

305

Fourier transform infrared (FT-IR) studies

The FT-IR spectra of ciprofloxacin HCl and its different drug resin complex




HCl and Indion 254. The peak due to the υOH group of the carboxylic acid at 2502.12

cm-1 was shifted to 2503.85 cm-1. The peaks appeared at 1624.73 cm-1 and 1384.03cm-1

were shifted to 1626.89 cm-1 and 1383.94 cm-1 assigned to the c=o and c-o group of

carboxylic acid respectively. In addition, an absorption band at 1025.11 cm-1 was

assigned to C-F group was shifted to 1036.50 cm-1. The peak at 943.99 cm-1 assigned to

the NH bending of amine was shifted to 942.48 cm-1. This indicates that there would be a

possibility of chemical modification in the DRC without any changes in basic nucleus of

the drug.

Taste evaluation of drug resin complex

The taste masking efficiency of resin was evaluated by bitterness level of

DRC.The bitterness level was divided in to four different categories like highly bitter,

moderately bitter, slightly bitter and no bitter. Taste evaluation of DRC in healthy human

volunteers confirmed that the taste of ciprofloxacin HCl was successfully masked by

complexing it with Indion 254 at 1:3 ratio. All the volunteers reported that DRC (1:3)

was tasteless and agreeable for a period of 10 minutes. Results are given in Table 6.5.2.5.

Dissolution profiles of ciprofloxacin HCl - Indion 254 complex in 0.1 NHCl

The dissolution rate of Ciprofloxacin HCl from DRC complex system (1:3) was

studied using 0.1 N HCl as the dissolution fluid. The results are given in Table 6.5.2.7

306

and are shown in Figs. 6.5.2.7A, 6.5.2.7B & 6.5.2.7C. The dissolution data were fitted

into various mathematical models such as zero order, first order and Hixson-Crowell’s

cube root models to assess the kinetics and mechanism of dissolution. The dissolution

data obeyed first order kinetic model as well as Hixson-Crowell’s cube root model. The

correlation coefficient (r) value observed in the analysis of dissolution data as per the

above two models are given in Table 6.5.2.8. The correlation coefficient (r) value is

greater than 0.910 indicating that the dissolution of ciprofloxacin HCl from ciprofloxacin

HCl - Indion 254 complex obeyed both first order and Hixson-Crowell’s cube root

models.

SUMMARY

Drug resin complexes (DRCs) of ciprofloxacin HCl - Indion 254 in 1:1,

1:2 and 1:3 ratios were prepared. The effects of drug-resin ratio, pH, resin soaking time,

and stirring time on complex formation were evaluated. Drug resin complex in 1:3 ratio

is better taste masking ability compared to other proportions. Hence 1:3 ratio are used for

further studies. Drug resin complexation was enhanced with increasing pH from 3 to 6.5.

A maximum percentage of drug loading was obtained at pH 6.5. Above pH 6.5, the

percentage of drug loading was decreased. The decreased complexation at lower pH is

due to excess H+ ions in the solution, which have more binding affinity to the –S03-

groups of resin and compete with the drug for binding. The percentage of the drug

loading was increasing with the soaking time up to 30 minutes. After 30 minutes of

soaking there was no significant increase in percentage of drug loading. In non soaking

resin matrix, the exchangeable groups are latent and coiled towards the back bone, hence

less drug loading efficiency. The resin soaking exposed the exchangeable groups

307

producing rapid drug exchange and hence higher drug binding. The percentage of the

drug loading was increasing with the stirring time up to three hours. After three hours of

stirring there was no significant increase in percentage of drug loading. It indicates three

hours contact time between drug and resin is optimimum to equilibrate the ion exchange

process to achieve maximum drug loading. Dissolution rate and dissolution efficiency

were evaluated for 1:3 ratio.

DSC and XRD indicated better drug inclusion in DRC. A stronger drug

amorphization and entrapment in DRC was observed. SEM studies indicated good

physical interaction of drug particles with Indion 254. The crystalline character of the

drug was lost and the components of the system (i.e., drug and resin) could not be

differentiated. In FT-IR studies, the band at 3377.60 cm-1 of ciprofloxacin HCl spectra



HCl and Indion 254. The peak due to the υOH group of the carboxylic acid at 2502.12

cm-1 was shifted to 2503.85 cm-1. The peaks appeared at 1624.73 cm-1 and 1384.03cm-1

were shifted to 1626.89 cm-1 and 1383.94 cm-1 assigned to the c=o and c-o group of

carboxylic acid respectively. In addition, an absorption band at 1025.11 cm-1 was

assigned to C-F group was shifted to 1036.50 cm-1. The peak at 943.99 cm-1 assigned to

the NH bending of amine was shifted to 942.48 cm-1. This indicates that there would be a

possibility of chemical modification in the DRC without any changes in basic nucleus of

the drug.

308

6.6 Formulation and in vitro evaluation of ciprofloxacin HCl orally disintegrating

6.6.1 Formulation of ciprofloxacin HCl orally disintegrating tablets


Ciprofloxacin HCl - Indion 254 complex (DRC)

Mannitol (Cargill, Germany)

Povidone (Sisco research laboratories, Mumbai)

Sodium starch glycolate (Kemphasol)

Crospovidone (Ozone international, Mumbai)

Aspartame (Cadila pharma, Ahmedabad)

Menthol (SD fine chem. Ltd, Mumbai)

Talc (Otto chemicals)

Magnesium stearate (Laboratory rasayan, SD fine chmicalslimited, Mumbai)

All materials used were of pharmacopoeial grades.

Formulation of ciprofloxacin HCl orally disintegrating tablets by using

Superdisintegrants

Ciprofloxacin HCl orally disintegrating tablets were prepared by direct compression

method. According to the formula given in Table 6.6.1, all the ingredients were passed

through 40-mesh sieve separately and collected. The DRC containing amount equivalent

to 100 mg of ciprofloxacin HCl was mixed with the other excipients and compressed into

tablets, after lubrication with magnesium stearate, and talc by using 16 station rotary

tablet compression machine equipped with 10 mm flat faced punches. The tablet weight

was adjusted to 700 mg.

309

Table 6.6.1:

Formulation of ciprofloxacin HCl ODTs prepared by direct compression method

6.6.1.1 Evaluation of granules

Pre compression parameters

Angle of repose, bulk density, compressibility index and Hausner’s ratio are

evaluated as procedure mentioned in chapter 5.3.1.1.

6.6.2 Evaluation of tablets

Hardness, thickness, friability, weight variation test, wetting time, drug content

estimation, in vitro disintegration time, in vitro dissolution studies, taste evaluation,

mouth feel, wetting time and water absorption ratio are evaluated as procedure mentioned

in chapter 5.3.2. Sampling intervals are 5, 10, 15, 20, 25, 30, 45, 60, 90 and 120 minutes

in dissolution studies. The amount of drug present in each sample was determined at 276


Ingredients

mg/tab

Formulation

CIT01 (mg)

CIT02 (mg)

CIT03 (mg)

CIT04 (mg)

CIT05 (mg)

DRC Mannitol Povidone Sodium starch glycolate Crosspovodine Aspartame

Menthol Talc Magnesium stearate

Total weight (mg)

477

82

42

51

---

28 6 7 7

700

477

82

42

---

51

28 6 7 7

700

477

67

42

33

33

28

6

7

7

700

477

72

42

---

61

28

6

7

7

700

477

63

42

---

70

28 6 7 7

700

310

Table 6.6.1.1:

Evaluation of precompression parameters of granules

Formula tion

Angle of repose (θ) *

Bulk density

(gm/cm3) *

Tapped density

(gm/cm3) * Compressibility

index (%) Hausner’s

ratio

CIT01

CIT02

CIT03

CIT04

CIT05

28.7±0.03

28.3±0.04

27.8±0.03

29.2±0.04

28.7±0.03

0.82±0.04

0.83±0.03

0.84±0.04

0.82±0.03

0.83±0.04

0.92±0.04

0.93±0.03

0.94±0.04

0.92±0.03

0.94±0.03

12.20

12.05

11.90

12.20

13.25

1.12

1.12

1.12

1.12

1.13 *All values are expressed as mean ± SE, n=3.

Table 6.6.2.A: Evaluation of postcompression parameters of ciprofloxacin HCl

ODTs

*All values are expressed as mean ± SE, n=5; **All values are expressed as mean ± SE, n=10; ***All values are expressed as mean ± SE, n=20.

Fig. 6.6.2.A: Comparison of disintegration time for ciprofloxacin HCl ODTs of different

superdisintegrants

7.29% SSG 76 7.29% CPV

69

4.71% SSG4.71% CPV

37 8.71% CPV28 10% CPV

19

01020304050607080

CIT01 CIT02 CIT03 CIT04 CIT05

Disin

tegr

atio

n tim

e (s

ec)

Formulation

Thickness (mm)*

Hardness (Kg/cm2)*

Friability (%)**

Weight variation (mg) ***

Drug content (%)**

Disintegration

time (sec)*

Wetting time

(sec)*

Water absortion

ratio

CIT01

CIT02

CIT03

CIT04

CIT05

5.34±0.04

5.35±0.03

5.34±0.03

5.34±0.04

5.35±0.03

4.0±0.65

4.1±0.47

4.2±0.58

4.3±0.44

4.2±0.63

0.17±0.08

0.21±0.06

0.20±0.08

0.22±0.07

0.20±0.07

1.4±0.84

1.8±0.65

1.6±0.82

1.6±0.58

1.5±0.64

87.03±1.34

85.21±1.26

86.97±1.38

87.07±1.31

86.21±1.73

76±9

69±7

37±8

28±6

19±5

60±8

58±8

30±7

25±6

17±6

0.37±0.03

0.40±0.03

0.41±0.04

0.39±0.04

0.42±0.03

311

Table 6.6.2.B: In vitro dissolution studies of ciprofloxacin HCl ODTs

Fig. 6.6.2.B1: Dissolution profiles of Fig. 6.6.2.B2: First order dissolution plots of

ciprofloxacin HCl ODTs containing drug ciprofloxacin HCl ODTs containing drug

as drug resin complexes and as drug resin complexes and

superdisintegrants superdisintegrants

0

20

40

60

80

100

0 50 100 150

% D

rug

rele

ase

Time (min)

CIT01 CIT02 CIT03CIT04 CIT05

0

0.5

1

1.5

2

0 50 100 150

Log%

dru

g un

rele

ased

Time (min)CIT01 CIT02 CIT03 CIT04 CIT05

Time (min)


CIT01 CIT02 CIT03 CIT04 CIT05 5

10

15

20

25

30

45

60

90

120

DE10 (%)

DE30 (%)

T50 (min)

K1(min-1) r

32.54+1.85

36.95+1.47

39.28+1.33

45.18+0.87

48.97+1.26

54.65+1.36

58.86+1.03

66.09+1.47

72.87+1.75

79.57+1.08

25.51

38.37

66.87

0.0104

0.9919

37.65+1.48

43.86+1.37

50.05+1.42

56.35+1.24

58.11+0.65

60.73+0.83

65.93+1.27

71.35+1.45

77.69+0.77

82.37+0.81

29.79

46.06

65.42

0.0106

0.9830

41.62+1.15

45.50+1.28

51.76+1.21

57.72+1.48

60.46+1.55

63.88+1.38

68.96+1.58

74.06+1.27

80.15+0.94

84.28+1.16

32.19

48.17

61.41

0.0113

0.9832

43.81+1.57

47.75+1.74

56.68+1.84

59.47+2.23

65.14+1.75

67.26+1.37

73.06+1.78

75.85+1.64

82.92+1.36

87.21+0.95

33.84

51.08

55.72

0.0124

0.9828

45.27+1.18

50.46+1.25

57.31+1.58

61.48+1.38

64.85+2.16

67.84+1.55

73.28+0.73

77.78+1.33

83.88+1.27

87.94+0.88

35.25

52.22

53.73

0.0129

0.9872

312

Table 6.6.2.C: Taste evaluation



In the present study, water insoluble diluents such as microcrystalline cellulose

and dicalcium phosphate and L-HPC were omitted from the study as they are expected to

cause an unacceptable feeling of grittiness in the mouth. Among the soluble diluents,

mannitol was selected as model soluble diluent considering its advantages in terms of

easy availability, cost-effectiveness, negative heat of dissolution and relative moisture

insensitivity. For each designed orally disintegrating tablet formulation, blend of drug in

a drug resin complex form [Ciprofloxacin HCl: Indion254; (1:3)] and excipients with

different concentrations of super disintegrating agents, was prepared and evaluated for

precompression properties. Results are shown in Table 6.6.1.1. Bulk density was found to

be between 0.82±0.04to 0.84±0.04 gm/cm3 and tapped density between 0.92±0.04 to

0.94±0.04 gm/cm3 for all formulations. From the density data, % compressibility was

calculated and was found to be between11.90 to 13.25. Angle of repose was found to be

in the range of 27.8±0.03 to 29.2±0.04. Hausner’s ratio was found to be below 1.12 to

1.13. All the formulations show parameters that are within prescribed limits and indicated

good flow property. Hence tablets were prepared by using direct compression technique.

Formulation

Bitterness

level

CIT01

CIT02

CIT03

CIT04

CIT05

****

****

****

****

****

313

The data obtained, of post compression parameters such as thickness, hardness,

friability, weight variation, uniformity of content, disintegration time, wetting time and

water absortion ratio are shown in Table 6.6.2.A. Thickness was found to be in range of

5.34±0.04 to 5.35 ±0.03mm in all formulations. The hardness was found to be in range of

4 to 5 kg/cm2 in all the formulations indicating good mechanical strength with an ability

to withstand physical and mechanical stress conditions while handling. In all the

formulations, the friability value is less than 1%. All the tablets passed weight variation

test as the % weight variation was within the Pharmacopoeial limits. The weight of all the

tablets was found to be uniform, with low standard deviation values indicating efficient

mixing of drug, superdisintegrants and excipients. The percentage drug content of all the

tablets was found to be between 85.21 ± 1.26% and 87.07 ±1.31% of ciprofloxacin HCl.

The results of in vitro disintegration of all the tablets were found to be within the

prescribed limits and satisfying the criteria of fast dissolving tablets. Formulations

containing crosspovidone, disintegrated faster when compared to other formulations

containing sodium starch glycolate. The disintegration time in relation to super

disintegrants concentration is shown in Fig. 6.6.2.A, reflecting that the higher the

concentration rapid will be the disintegration. The disintegration time for each tablet was

found to be less than one and half minute and the tablets containing crosspovidine (10%;

CIT05) showed lowest disintegration time (19±5 sec). The lowest wetting time (17±5

sec) and highest water absorption ratio (0.42±0.03) was obtained with formulation

CIT05. The faster disintegration of superdisintegrants can be attributed to the increase in

the rate and extent of water uptake and consequent swelling and increased hydrodynamic

pressure to induce complete disintegration.

314

The results of in vitro dissolution studies of various formulations, CIT01 to

CIT05, in 0.1 N HCl, are shown in Table 6.6.2.B and in Figs. 6.6.2.B1 & 6.6.2.B2. All




In the presence of disintegrants, the matrix might be distorted, resulting in higher

surface area, allowing the superdisintegrants to readily pick up water and thereby cause a

rapid rate of dissolution. The concentration of superdisintegrants in the formulation also

affected the dissolution rate. In vitro dissolution rate of orally disintegrating tablets of

ciprofloxacin HCl increased with increase in concentration of super disintegrants. Tablets

formulated with10% w/w of crosspovidone, showed better dissolution rate among all

other formulations. The dissolution of ciprofloxacin HCl from all the tablets followed

first order kinetics. Plots of log % drug remained vs time were found to be linear. The

dissolution kinetic data is given in Table 6.6.2.B. Among all the formulations CIT05

which contain 10% of crosspovidone gave the highest dissolution (87.94 %) at the end of

120 minutes. The dissolution rate constant (K1), half-life, DE10% and DE30% for

formulation CIT05 (10% crosspovidone) were 0.0129 min-1, 53.73 minutes, 35.25 and

52.22% respectively.

A panel of selected healthy human volunteers evaluated the orally disintegrating

tablets for taste masking. None of the formulation show any bitter taste for a period of 10

minutes when tablets are evaluated as procedure mentioned in chapter 6.1.3, which shows

excellent taste masking effect of the drug resin complex [Ciprofloxacin HCl: Indion 254;

(1:3)]. The healthy human volunteers participated in taste evaluation test were asked to

315

give their opinion about the feeling of smoothness or grittiness of the dispersion soon

after held in mouth. All the formulations showed smooth and pleasant mouth feeling, thus

fulfill the requirements of orally disintegrating tablets.





masking the bitterness. The basic method considered for the development of taste masked

ciprofloxacin HCl orally disintegrating tablets is the direct compression method by using

mannitol as diluent and sodium starch glycolate (SSG) & crospovidone (CPV) as

superdisintegranting agents at four concentrations (4.71, 7.29, 8.71 and 10%) with the

drug in a drug resin complex form (Ciprofloxacin HCl: Indion 254; 1:3). Based on the

disintegration time and wetting time, superdisintegrants can be ranked as crospovidone

(CPV) > sodium starch glycolate (SSG). All prepared tablets were evaluated for weight

variation, friability, hardness, disintegration time, drug content, taste, mouth feel, wetting

time and dissolution rate. Disintegration time and wetting time of orally disintegrating

tablets of ciprofloxacin HCl decreased with increase in concentration of super

disintegrants and is found to be less for tablets formulated using 10 % w/w

crosspovidone. The dissolution of drug followed first order kinetics in all formulations.

Tablets formulated with 10% w/w of crosspovidone, showed better dissolution rate

among all other formulations. May be exhibiting these result due to the concentration

used and swelling property of crosspovidone. Thus the technique of preparation of DRC

316

of Ciprofloxacin HCl with Indion 254 gave ODTs of pharmacopeial quality, pediatric

patient palatability, convenient and inexpensive.

6.7 Formulation and evaluation of ciprofloxacin HCl Dry syrup



Materials

Ciprofloxacin HCl - Indion 254 complex (DRC) Ciprofloxacin HCl (gift sample from Darvin pvt.ltd) Sodium citrate (Qualigens fine chemicals) Citric acid (Otto kemi, Mumbai) Lutrol F 68 (gift sample from BASF) Sorbitol (gift sample from Cargill, Germany) Erythritol (gift sample from Cargill, Germany) Aspartame (Cadila pharma, Ahmedabad) Sodium benzoate (Qualigens fine chemicals) Xanthan gum (Kemphasol, Mumbai) Sodium carboxymethyl cellulose (Central Drug House laboratory reagents) Orange flavor (PAN Aroma Madras Pvt.Ltd, Chennai) Methods

Drug resin complex and other ingredients were passed through 60-mesh sieve and

collected individually. According to the formula given in Table 6.7.1, all ingredients were

accurately weighed and blended homogeneously. This homogeneous dry syrup was filled

in to an amber colored bottle and stored in a dry place at room temperature.

317


6.7.2 Evaluation of dry syrup

Sedimentation volume, pH, specific gravity, drug content, taste evaluation, mouth


5.4.2. Sampling intervals are 5, 10, 15, 20, 25, 30, 45, 60, 90 and 120 minutes in



Ingredients / 5 ml

Formulation CIDS01

(mg) CIDS02

(mg) CIDS03

(mg) CIDS04

(mg) CIDS05

(mg) Drug/DRC Sodium citrate Citric acid Lutrol F 68 Sorbitol Erythroitol Aspartame Sodium benzoate Xanthan gum Sodium carboxymethyl Cellulose Orange flavour

100

82

82

6

2200

---

---

0.5

---

---

qs

477

82

82

34

2200

---

---

0.5

150

---

qs

477

80

80

34

---

2200

63

0.5

120

---

qs

477

84

84

34

---

2200

74

0.5

100

---

qs

477

84

84

34

---

2200

74

0.5

---

100

qs

318

Table 6.7.2.A: Evaluation of physical properties of reconstituted dry syrups

Table 6.7.2.B: Taste evaluation of reconstituted dry syrups

Formulation

Bitterness level

CIDS01

CIDSO2

CIDSO3

CIDSO4

CIDSO5

*

***

***

****


Formulation


( ± s.d., n=3)


C

( ± s.d., n=3)



( ± s.d., n=3)

Day- 1 Day- 7 Day- 1 Day- 7 Day- 1 Day- 7 Day- 1 Day- 7

CIDS02

CIDS03

CIDS04

CIDS05

98.2+0.75

88.3+0.49

76.5+0.69

67.6+0.85

97.9+0.84

87.9+0.66

75.1+0.91

63.2+0.64

5.13+0.03

5.21+0.05

5.24+0.05

5.64+0.04

5.10+0.05

5.16+0.05

5.17+0.04

5.53+0.03

1.26+0.03

1.22+0.05

1.22+0.04

1.21+0.03

1.27+0.03

1.23+0.05

1.24+0.04

1.25+0.03

85.67+1.32

86.73+1.42

88.06+1.84

88.36+0.85

83.02+1.26

83.86+1.27

85.89+0.84

85.64+0.61

319

Table 6.7.2.C.1: In vitro dissolution studies of ciprofloxacin HCl reconstituted dry syrups on day 1

Fig. 6.7.2.C.1A: Dissolution profiles of Fig. 6.7.2.C.1B: First order dissolution plots of

ciprofloxacin HCl reconstituted dry syrups ciprofloxacin HCl reconstituted dry syrups containing

containing drug as drug resin complexes on day 1 drug as drug resin complexes on day 1

0

20

40

60

80

100

0 50 100 150

% D

rug

rele

ase

Time (min)CIDS02 CIDS03CIDS04 CIDS05

0

0.3

0.6

0.9

1.2

1.5

1.8

0 50 100 150

Log%

dru

g un

rele

ased

Time (min)CIDS02 CIDS03 CIDS04 CIDS05

Time (min)


CIDS02 CIDS03 CIDS04 CIDS05 5

10

15

20

25

30

45

60

90

120

DE10 (%)

DE30 (%)

T 50 (min)

K1(min-1) r

51.38+1.14

55.78+1.27

60.24+1.45

63.52+1.37

66.92+0.96

68.35+1.62

72.21+1.84

75.68+1.17

81.74+1.31

87.11+0.86

39.64

55.34

64.02

0.0108

0.9918

53.10+1.28

57.88+1.33

62.21+1.63

66.18+1.85

68.13+1.43

70.26+1.74

74.72+1.81

79.31+0.87

82.68+1.37

88.59+1.82

41.02

57.11

60.18

0.0115

0.9883

55.87+1.26

60.26+1.26

64.05+1.20

67.69+1.42

71.27+1.67

73.37+0.80

76.38+1.35

80.48+1.77

85.76+0.85

89.27+0.67

43.00

59.30

57.87

0.0120

0.9887

56.96+1.33

61.38+1.46

65.90+1.47

69.42+0.73

70.35+1.64

74.81+1.38

78.01+1.58

82.95+1.22

86.62+0.96

89.55+0.74

43.83

60.24

56.78

0.0122

0.9826

320

Table 6.7.2.C.2: In vitro dissolution studies of ciprofloxacin HCl reconstituted dry syrups on day 7

Fig. 6.7.2.C.2A: Dissolution profiles of Fig. 6.7.2.C.2B: First order Dissolution plots of



on day 7 on day 7

0

20

40

60

80

100

0 50 100 150

% D

rug

rele

ase


0

0.3

0.6

0.9

1.2

1.5

1.8

0 50 100 150

Log%

dru

g un

rele

ased


Time (min)


CIDS02 CIDS03 CIDS04 CIDS05 5

10

15

20

25

30

45

60

90

120

DE10 (%)

DE30 (%)

T 50 (min)

K1(min-1) r

49.86+1.38

54.03+2.27

58.96+1.54

61.84+1.29

65.05+1.13

66.34+2.15

70.27+1.82

75.04+1.69

82.87+1.14

84.64+0.74

38.44

53.82

66.87

0.0104

0.9858

52.56+1.54

56.67+1.72

61.04+1.86

64.73+1.27

67.54+1.76

69.37+1.36

74.34+1.41

78.28+2.15

82.74+1.18

87.05+0.83

40.45

56.20

64.02

0.0108

0.9874

54.58+1.53

59.28+1.62

62.68+1.30

66.27+2.21

69.74+1.74

71.65+1.48

74.95+1.62

78.83+1.39

84.57+1.44

87.58+0.68

42.11

58.06

62.69

0.0111

0.9870

55.35+1.46

59.81+1.62

64.36+1.85

67.73+2.13

70.12+1.47

73.14+1.74

76.48+1.38

81.30+1.28

85.26+0.95

87.95+0.68

42.63

58.99

61.41

0.0113

0.9796

321


For each designated dry syrup formulation, blend of drug in a drug resin complex

form [Ciprofloxacin HCl: Indion254; (1:3)] and excipients with different concentrations

of suspending agents, was prepared. In the CIDS01 formulation, pure drug was

formulated with 22 times of sorbitol. There was no significant change in the masking of

bitter taste of the drug with 22 times of sorbitol. Hence DRC [Ciprofloxacin HCl: Indion

254; (1:3) complex) was used instead of pure drug for formulations CIDS02 to CIDS05.

Various concentrations of suspending agents were added to formulations CIDS02 to

CIDS05. After reconstitution, each dry syrup formulation was evaluated for

sedimentation volume, pH, specific gravity, drug content and taste on day 1 & day 7.

Results are shown in Tables 6.7.2.A and 6.7.2.B. Percentage sedimentation volume was

found to be between 67.6+0.85 to 98.2+0.75 on day1and 63.2+0.64 to 97.9+0.84 on day

7. Each sample of the formulation had good visual appearance and high sedimentation

volume, which indicates that the DRC formed flocs.




below5.64+0.04 and 5.10+0.05 to 5.53+0.03 on day 1 and day 7 respectively. Specific





322

85.67+1.32 to88.36+0.85 & 83.02+1.26 to 85.89+0.84 of ciprofloxacin HCl on day 1 and

day 7 respectively.



The results of in vitro dissolution studies of various formulations, CIDS02 to CIDS05, in

0.1 N HCl, are shown in Table 6.7.2.C.1 and in Figs. 6.7.2.C.1A & 6.7.2.C.1B on day 1.

Day 7 results are shown in Table 6.7.2.C.2 and in Figs. 6.7.2.C.2A & 6.7.2.C.2B. All







6.7.2.C.2 on day 7. The percentage of drug dissolved from CIDS04 & CIDS05 was to be

more than the other two formulations. CIDS04 has the more sedimentation volume with

ease of redispersibility and comparable drug release profile with CIDS05 formulation.

The dissolution rate constant (K1), half-life, DE10 and DE30 for formulation CIDS04 were

0.120 min-1, 57.87minutes, 43.00% and 59.30% respectively on day 1. On day 7,

dissolution rate constant (K1), half-life, DE10% and DE30% for formulation CRDS04 were

0.111 min-1, 62.69 minutes, 42.11% and 58.06% respectively.


bitter taste masking by procedure mentioned in chapter 6.1.3. CIDS01 was highly bitter

in taste. CIDS02 & CIDS03 moderately bitter and CIDS04 & CIDS05 were no bitter in

323

taste for a period of 10 minutes. The healthy human volunteers participated in taste


grittiness of the dispersions soon after held in mouth. CIDS04 & CIDS05 showed smooth

and pleasant mouth feeling.


Complexation of ciprofloxacin HCl with ion exchange resin is a simple and

efficient technique for masking the bitterness of the drug. Dry syrup was prepared by

passing all the ingredients through 60-mesh sieve. Ciprofloxacin HCl dry syrup

formulation was prepared by using sorbitol, erythroitol & aspartame as sweeting agents

and sodium carboxymethyl cellulose & xanthan gum as suspending agents at different

concentrations with the drug in a drug resin complex form [Ciprofloxacin HCl:

Indion254; (1:3)]. The formulated dry syrup was evaluated for drug content, taste of the

syrup after reconstitution, pH of the syrup, sedimentation volume, specific gravity and

dissolution characteristics. The sedimentation volume and redispersiblity was more for

the dry syrup containing 3.38% of xanthan gum (CIDS04). The concentration and nature

of the xanthan gum used in these DRCs formulations drives desirable viscous that it helps

more sedimentation volume with ease of redispersibility and increased dissolution rate

compare to other liuid formulations.The dissolution of the drug from the reconstituted

syrup follows first order kinetics. Thus the technique of preparation of DRC of

ciprofloxacin HCl with Indion 254 gave dry syrup of pharmacopeial quality, pediatric

patient palatability, convenient and inexpensive.

324

6.8 Preparation and evaluation of solid dispersions of ciprofloxacin HCl with

stearic acid and PEG 1500

6.8.1 Preparation of solid dispersions of ciprofloxacin HCl with stearic acid and

PEG 1500


Materials


Stearic acid (Laboratory rasayan, SD fine chemicals limited, Mumbai)

Poly ethylene glycol (PEG) (Kemphasol, Mumbai)

Methods

Solid dispersions were prepared by fusion method. According to the formula

given in Table 6.8.1, accurately weighed quantities of ciprofloxacin HCl, steric acid and

PEG 1500 in different proportions, were taken a beaker. The total mixture was melted at

75oc with constant stirring. The mixture was cooled at room temperature. The obtained

solidified mass was scrapped, pulverized and passed through 40-mesh sieve.

Table 6.8.1:

Preparation of solid dispersions of ciprofloxacin HCl with stearic acid and

PEG 1500

S.No

Drug + Carrier +

Chanelling agent

Solid Dispersio

n Code

Dispersion ratio (Drug : Carrier:

Chanelling agent)

Concentration of PEG 1500

(w/w %)

Prepation method

01

02

03

04

05

06

Ciprofloxacin HCl

+ Stearic acid

+ PEG 1500

CSP01

CSP02

CSP03

CSP04

CSP05

CSP06

1:1:0

1:1:0.2

1:1:0.3

1:1:0.4

1:1:0.6

1:1:0.8

0

10

15

20

30

40

Fusion method

325

6.8.2 Evaluation of solid dispersions of ciprofloxacin HCl with stearic acid and

PEG 1500


diffractometry, SEM, FT-IR Studies, taste evaluation, drug content and in vitro drug

release from solid dispersion. Sampling intervals are 15, 30, 45, 60, 90 and 120minutes in



(A)

(C)

(B)

(E)

(D)

(F)

(G)

(H)

(I)

Temperature (°C)

Fig. 6.8.2.1: DSC Thermograms of (A) Ciprofloxacin HCl, (B) Stearic acid, (C) PEG 1500,

(D) C-S-P (1:1:0), (E) C-S-P (1:1:0.2), (F) C-S-P (1:1:0.3), (G) C-S-P (1:1:0.4), (H) C-S-P (1:1:0.6) and

(I) C-S-P (1:1:0.8)

326

Table 6.8.2.1: DSC Studies of ciprofloxacin HCl-stearic acid-PEG 1500 solid dispersion systems

(B)

(A)

(C)

(D)

(E)

(F)

(G)

(H)

(I)

2θ

Fig. 6.8.2.2: X-Ray Diffractograms of (A) Ciprofloxacin HCl, (B) Stearic acid, (C) PEG 1500,


(I) C-S-P (1:1:0.8)

Product

DSC (°C) Fractional crystallinity (% )

Tpeak (°C)

ΔHfusion (J/g)

Ciprofloxacin HCl

C-S- P (1:1:0)

C-S-P (1:1:0.2)

C-S-P (1:1:0.3)

C-S-P (1:1:0.4)

C-S-P (1:1:0.6)

C-S-P (1:1:0.8)

152.1

---

122.0

107.5

108.3

111.2

125.1

162.9

---

61.80

46.11

51.82

47.52

56.97

---

---

37.94

28.31

31.81

29.17

34.97

327

Table 6.8.2.2:

% RDC values from X-ray diffractograms of ciprofloxacin HCl-stearic acid PEG 1500 solid

dispersion Systems Product 2θ % RDC

Ciprofloxacin HCl

C-SA-PEG 1500 (1:1:0)

C-SA-PEG 1500 (1:1:0.2)

C-SA-PEG 1500 (1:1:0.3)

C-SA-PEG 1500 (1:1:0.4)

C-SA-PEG 1500 (1:1:0.6)

C-SA-PEG 1500 (1:1:0.8)

26163.56

6418.11

9711.26

963.56

1013.63

13910.77

16641.56

-

24.53

37.12

3.68

3.87

53.17

63.60


(A) (B) (C)

Fig. 6.8.2.3A: SEM Photographs of (A) Ciprofloxacin HCl (B) Stearic acid and(C) PEG 1500

(A) (B) (C)

Fig. 6.8.2.3B: SEM Photographs of (A) Ciprofloxacin HCl-Stearic acid-PEG (1:1:0), (B) Ciprofloxacin HCl-Stearic acid-PEG (1:1:0.2) and

(C) Ciprofloxacin HCl-Stearic acid-PEG (1:1:0.3)

(A) (B) (C)

Fig. 6.8.2.3C: SEM Photographs of (A) Ciprofloxacin HCl-Stearic acid-PEG (1:1:0.4),

(B) Ciprofloxacin HCl-Stearic acid-PEG (1:1:0.6) and

(C) Ciprofloxacin HCl-Stearic acid-PEG (1:1:0.8)

328

(A)

(C)

(D)

(E)

(F)

(G)

(H)

(I)

(B)

Wave number (cm-1)

Fig. 6.8.2.4: FTIR Spectras of (A) Ciprofloxacin HCl, (B) Stearic acid, (C) PEG 1500,


(I) C-S-P (1:1:0.8)

Table 6.8.2.5: Taste evaluation Table 6.8.2.6: Drug content estimation

of solid dispersions of solid dispersion Solid

dispersion Code

Bitterness level

Formulation

Drug content ( ± s.d.,n=3)

CSP01

CSPO2

CSPO3

CSPO4

CSPO5

CSPO6

****

****

****

****

****

****

CSP01

CSPO2

CSPO3

CSPO4

CSPO5

CSPO6

85.27+2.06

88.51+1.83

90.37+1.35

93.22+1.44

95.31+0.95

98.41+1.02 *highly bitter, **moderately bitter, ***slightly bitter, ****no bitter

329

Table 6.8.2.7: In vitro drug release of ciprofloxacin HCl from solid dispersions

containing stearic acid and different concentrations of PEG 1500

*Hixson- crowell’s cube root dissolution rate constant

Fig. 6.8.2.7A: Dissolution profiles of Fig. 6.8.2.7B: First order dissolution plots of

ciprofloxacin HCl solid dispersions containing ciprofloxacin HCl solid dispersions containing

stearic acid and different concentrations of stearic acid and different concentrations of

PEG 1500 PEG 1500

0

20

40

60

80

100

120

0 50 100 150

% D

rug

rele

ase

Time (min)CSP01 CSP02 CSP03

0.00

0.40

0.80

1.20

1.60

0 50 100 150

Log%

dru

g un

rele

ased

Time (min)CSP01 CSP02 CSP03CSP04 CSP05 CSP06

Time (min)


CSP01 CSP02 CSP03 CSP04 CSP05 CSP06

0

15

30

45

60

90

120

DE30 (%)

DE45 (%)

T 50 (min)

K1 (min-1) r

*KH(mg1/3

.min-1

)

0

34.04+1.36

40.15+1.52

45.31+2.15

51.27+1.74

55.64+1.31

58.78+0.77

27.06

32.28

150.46

0.0046

0.9761

0.0056

0

42.54+1.83

47.65+2.31

55.16+1.84

61.22+1.95

66.37+1.58

71.63+1.25

33.18

39.26

103.76

0.0067

0.9901

0.0078

0

47.84+2.73

52.96+1.62

61.93+1.84

66.84+1.84

70.88+0.98

76.58+0.86

37.16

43.92

91.19

0.0076

0.9851

0.0082

0

58.15+1.71

64.42+1.63

68.07+1.28

73.45+0.81

82.23+1.29

89.58+1.48

45.18

52.20

52.79

0.0131

0.9912

0.0122

0

73.62+1.69

81.86+1.53

86.28+1.58

91.94+1.44

95.20+0.94

---

57.28

66.21

29.79

0.0233

0.9938

0.0174

0

80.20+1.47

91.37+1.84

96.21+1.27

98.81+1.75

---

---

62.94

73.23

11.23

0.0617

0.9993

0.0362

330

Table 6.8.2.8: Correlation coefficient (r) values in the analysis of dissolution data

as per first order and Hixson-Crowell’s cube root models

Solid Dispersion code

Solid dispersion System

Correlation coefficient (r) First order

Hixson-Crowell’s

CSP01

CSP02

CSP03

CSP04

CSP05

CSP06

CF-SA-PEG 1500 (1:1:0)

CF-SA-PEG 1500 (1:1:0.2)

CF-SA-PEG 1500 (1:1:0.3)

CF-SA-PEG 1500 (1:1:0.4)

CF-SA-PEG 1500 (1:1:0.6)

CF-SA-PEG 1500 (1:1:0.8)

0.9761

0.9901

0.9851

0.9912

0.9938

0.9993

0.9718

0.9856

0.9790

0.9974

0.9870

0.9975 CF=Ciprofloxacin HCl SA= Stearic acid PEG 1500= Poly Ethylene Glycol 1500


DSC was used to characterize the solid dispersions prepared with ciprofloxacin

HCl, stearic acid and PEG 1500. The DSC thermograms of ciprofloxacin HCl, stearic

acid, PEG 1500 and various solid dispersions are shown in Fig. 6.8.2.1. Fractional

crystallinity [(ΔHf) sample / (ΔHf) crystal] values are given in Table 6.8.2.1. The DSC

curve of pure ciprofloxacin HCl exhibits a two merged broad endothermic peaks at

152.1°C and 165.7 °C. Stearic acid and PEG 1500 showed sharp endothermic peaks at

59.8°C and 52.9°C respectively due to their melting points. In the thermograms of

ciprofloxacin HCl - stearic acid - PEG 1500 solid dispersions (Fig. 6.8.2.1 D, E, F, G, H

& I ), The merged endothermic peak of the parent drug at 152.1°C and 165.7 °C (Fig.

6.8.2.1 A) was shifted in between 107.5 °C to 125.1 °C in the solid dispersions (Fig.

6.8.2.1 D, E, F, G, H & I ) and the intensity (or height) of the endothermic peak of parent

drug was reduced in all solid dispersions (Fig. 6.8.2.1 D, E, F, G, H & I ) indicating

fusion of ciprofloxacin HCl with stearic acid and PEG 1500. The crystallinty of

331

ciprofloxacin HCl in solid dispersions was markedly reduced. The crystallinity level is

obtained by measuring the enthalpy of fusion for a sample (ΔHf) and comparing it to the

enthalpy of fusion for the fully crystalline material (ΔHf) crystal.

Powdered X-ray diffraction patterns of ciprofloxacin HCl, stearic acid, PEG 1500

and their solid dispersions with different ratios are shown in Fig. 6.8.2.2. XRD of

ciprofloxacin HCl exhibited characteristic diffraction peaks at 8.46°, 9.30°, 19.11°,

19.56°, 20.02°, 23.41°, 24.97°, 26.23°, 26.71, 27.17, 29.44 and 29.73 ° indicating its

crystalline nature. The diffractogram of stearic acid exhibited characteristic peaks at

6.99°, 21.47° and 23.81° due to its crystalline nature. Whereas diffractogram of PEG

1500 exhibited characteristic peaks at 13.57°, 19.20°, 23.25°, 23.59° and 27.29°.

Crystallinity can be determined by comparing some representative peak heights in the

diffraction patterns of solid dispersion with those of a reference. The relationship used for

the calculation of crystallinity was relative degree of crystallinity (RDC).

RDC= Isam / Iref,


height at the same angle for the reference with the highest intensity.

XRD patterns of ciprofloxacin HCl and its solid dispersions with stearic acid and

PEG 1500 are shown in Fig. 6.8.2.2. The diffraction peaks were much reduced in solid

dispersion systems. Pure drug peak at 9.30◦ (2θ) was used for calculating RDC of solid

dispersion systems are shown in Table 6.8.2.2. The RDC values of the complexes were

less than those of the drug in all cases. Furthermore, a reduced number of signals were

noticeable in the solid dispersions, of remarkably lowered intensity compared to the free

molecules.

332


characters for ciprofloxacin HCl, stearic acid, PEG 1500 and their solid dispersions with

different ratios. The SEM photographs of various products are shown in Figs.6.8.2.3A,

6.8.2.3B, 6.8.2.3C and 6.8.2.3D. SEM of ciprofloxacin HCl showed paddy husk shaped

crystals. The SEM of stearic acid showed scrap shaped particles of different sizes. The

surfaces are irregular and uneven. In the SEM of PEG 1500, particles are in foamy cluster

shaped. Figs. 6.8.2.3B, 6.8.2.3C and 6.8.2.3D show the SEM of solid dispersions of

ciprofloxacin HCl-stearic acid-PEG 1500. In the SEM of all these systems, the crystalline

character of ciprofloxacin HCl was absent and the crystals of the components i.e,

ciprofloxacin HCl and stearic acid &PEG 1500 could not be differentiated. The particles

in all the systems were all irregular in shape. As the concentration of PEG 1500 increases

in solid dispersion the loose clumpy mass gets adhered.These microscopic observations

indicated a good physical interaction of drug particles with stearic acid and PEG 1500.

The FT-IR spectra of ciprofloxacin HCl and its different solid dispersion complex



3441.65 cm-1 in optimized solid dispersion prepared with 1:1:0.8 ratio of ciprofloxacin

HCl, stearic acid and PEG 1500. The peak due to the υOH group of the carboxylic acid at

2502.12 cm-1 was shifted to 2503.67 cm-1. The peaks appeared at 1624.73 cm-1 and

1384.03cm-1 were shifted to 1624.99 cm-1 and 1384.59 cm-1 assigned to the c=o and c-o

group of carboxylic acid respectively. In addition, an absorption band at 1025.11 cm-1

was assigned to C-F group was shifted to 1046.97 cm-1. The peak at 943.99 cm-1 assigned

to the NH bending of amine was shifted to 948.02 cm-1. This indicates that there would

333

be a possibility of chemical modification in the solid dispersions without any changes in

basic nucleus of the drug.

Solid dispersions of ciprofloxacin HCl-stearic acid-PEG 1500 in 1:1:0, 1:1:0.2,

1:1:0.3, 1:1:0.4, 1:1:0.6 and 1:1:0.8 ratios were prepared by fusion method. The solid

dispersions prepared are listed in Table 6.8.1. Drug content of solid dispersions was

found to be 85.27+2.06% to 98.41+1.02%. Ciprofloxacin HCl release from the solid

dispersion without PEG 1500 and with different concentrations of PEG 1500 was studied

in 0.1 N HCl up to 2 hours. The average percent cumulative release of the ciprofloxacin

HCl solid dispersion without channeling agent (PEG 1500) was found to be 58.78+0.

77% at the end of 2 hours and with channeling agent (PEG 1500) at concentrations of 10,

15 and 20 percent was found to be 71.58+1.25%, 76.58+0.86% and 89.58+1.48% at the

end of 2 hours. Drug release from solid dispersion with 30% PEG 1500 concentration at

the end of 90 minutes was found to 95.20+0.94% and for 40% PEG 1500 concentration at

the end of 60 minutes was 98.81+1.75%. The increased dissolution rate may be due to the

higher concentration of channeling agent (PEG 1500) and better wettability of

ciprofloxacin HCl in the dispersion.

The dissolution data were fitted into various mathematical models such as first

order and Hixson-Crowell’s cube root models to assess the kinetics and mechanism of

dissolution. The dissolution data obeyed first order kinetic model as well as Hixson-

Crowell’s cube root model. The correlation coefficient (r) values observed in the analysis

of dissolution data are presented in Table 6.8.2.8. All the ‘r’ values are greater than 0.910

indicating that the dissolution of ciprofloxacin HCl from all the solid dispersion systems

prepared obeyed both first order and Hixson-Crowell’s cube root models.

334

The K1 and DE30% values increased as the proportion of PEG1500 in the solid

dispersion system was increased in each case. Solid dispersion (CSP06) having 40 % of

PEG 1500, gave higher enhancement in the dissolution rate and efficiency when

compared to other percentage solid dispersion. The hydrophilic polymer gave a marginal

increase in the dissolution rate of ciprofloxacin HCl. Increasing the concentration of

hydrophilic polymer has further enhanced the dissolution rate and DE of ciprofloxacin

HCl from solid dispersion.

The taste masking efficiency of stearic acid and PEG 1500 was evaluated by

bitterness level of solid dispersion. The bitterness level was divided in to four different

categories like highly bitter, moderately bitter, slightly bitter and no bitter. Taste

evaluation of solid dispersions in healthy human volunteers confirmed that the taste of

ciprofloxacin HCl was successfully masked by solid dispersion with stearic acid and PEG

1500. All the volunteers reported that all solid dispersions were tasteless and agreeable

for a period of 10 minutes and results are given in Table 6.8.2.5.

SUMMARY

Solid dispersions of ciprofloxacin HCl-stearic acid-PEG 1500 in 1:1:0, 1:1:0.2,

1:1:0.3, 1:1:0.4, 1:1:0.6 and 1:1:0.8 ratios were prepared by fusion method. 1:1:0.8 ratio

of ciprofloxacin HCl-stearic acid-PEG 1500 exhibited higher rates of dissolution and

dissolution efficiency values than1:1:0, 1:1:0.2, 1:1:0.3, 1:1:0.4 and1:1:0.6. The

hydrophilic polymer (PEG 1500) gave a marginal increase in the dissolution rate of

ciprofloxacin HCl. Addition of hydrophilic polymer has further enhanced the dissolution

rate and efficiency (DE) of ciprofloxacin HCl from solid dispersion. The dissolution data

obeyed first order kinetic model as well as Hixson-Crowell’s cube root model. The K1

335

and DE30% values increased as the proportion of PEG1500 in the solid dispersion system

was increased in each case. Taste evaluation of solid dispersions in healthy human

volunteers confirmed that the taste of norfloxacin was successfully masked by solid

dispersion with stearic acid and PEG 1500 in all ratios. All the volunteers reported that all

solid dispersions were tasteless and agreeable for a period of 10 minutes.

The solid dispersions of ciprofloxacin HCl with stearic acid and PEG 1500 were

studied by DSC, XRD, SEM and FT-IR spectra studies. DSC and XRD indicated better

drug inclusion in solid dispersion. SEM studies indicated good physical interaction of

drug particles with stearic acid and PEG 1500. The crystalline character of the drug was

lost and the components of the system (i.e., Ciprofloxacin HCl, Stearic acid and PEG

1500) could not be differentiated. In FT-IR studies, the band at 3377.60 cm-1 of

ciprofloxacin HCl spectra suggested the NH stretching vibration in a secondary amine,

which was shifted to 3441.65 cm-1 in optimized solid dispersion prepared with 1:1:0.8

ratio of ciprofloxacin HCl, stearic acid and PEG 1500. The peak due to the υOH group of

the carboxylic acid at 2502.12 cm-1 was shifted to 2503.67 cm-1. The peaks appeared at

1624.73 cm-1 and 1384.03cm-1 were shifted to 1624.99 cm-1 and 1384.59 cm-1 assigned

to the c=o and c-o group of carboxylic acid respectively. In addition, an absorption band

at 1025.11 cm-1 was assigned to C-F group was shifted to 1046.97 cm-1. The peak at

943.99 cm-1 assigned to the NH bending of amine was shifted to 948.02 cm-1. This

indicates that there would be a possibility of chemical modification in the solid

dispersions without any changes in basic nucleus of the drug.

336

6.9 Formulation and evaluation of ciprofloxacin HCl dry syrup with solid dispersion



Materials Ciprofloxacin HCl solid dispersion (Prepared with Stearic acid and PEG 1500) Ciprofloxacin HCl (gift sample from Darvin pvt.ltd) Citric acid (Otto kemi, Mumbai) Lutrol F 68 (gift sample from BASF) Erythritol (gift sample from Cargill, Germany) Aspartame (Cadila pharma, Ahmedabad) Xanthan gum (Kemphasol, Mumbai) Sodium carboxymethyl cellulose (Central Drug House laboratory reagents) Orange flavor (PAN Aroma Madras Pvt.Ltd, Chennai) Sunset yellow (Indian research products, Madras)

Methods

Ciprofloxacin HCl solid dispersion and other ingredients were passed through

60-mesh sieve and collected individually. According to the formula given in Table 6.9.1,

all ingredients were accurately weighed and blended. Two different suspending agents

were added in two different formulas. The formulations were filled in to amber colored

bottles and stored in a dry place at room temperature.

337


6.9.2 Evaluation of ciprofloxacin HCl dry syrup

Sedimentation volume, pH, specific gravity, drug content, taste evaluation mouth


5.4.2. Sampling intervals are 5, 10, 15, 20, 25, 30 and 45 minutes in dissolution studies.

The amount of drug present in each sample was determined at 276 nm by UV

spectrophotometer.

Table 6.9.2.A:

Evaluation of physical properties of ciprofloxacin HCl reconstituted dry syrups

Ingredients / 5 ml of reconsisted

syrup

Formulation

CSDS01 (mg)

CSDS02 (mg)

CSDS03 (mg)

CSDS04 (mg)

CSDS05 (mg)

Drug/Solid dispersion of CSP06 Erythritol Lutrol F 68 Citric acid Aspartame Xanthan gum Sodium carboxymethyl Cellulose Orange flavour Sunset yellow

100

1150

220

28

---

---

75

qs

qs

305

1150

220

28

---

75

---

qs

qs

305

1150

220

28

55

---

---

qs

qs

305

1150

220

28

55

90

---

qs

qs

305

1150

220

28

55

---

90

qs

qs

Formula tion


( ± s.d., n=3)


C

( ± s.d., n=3)



( ± s.d., n=3)

Day- 1 Day- 7 Day- 1 Day- 7 Day- 1 Day- 7 Day- 1 Day- 7 CSDSO3

CSDSO4

CSDSO5

---

80.2+1.02

74.5+0.82

---

78.4+0.94

68.5+1.37

4.74+0.04

4.55+0.04

4.53+0.03

---

4.51+0.05

4.52+0.04

1.12+0.04

1.24+0.03

1.22+0.04

---

1.26+0.05

1.24+0.04

98.88+1.20

98.26+1.38

98.48+1.22

---

96.31+1.63

96.58+1.32

338

Table 6.9.2.B: Taste evaluation of ciprofloxacin HCl reconstituted dry syrups Solid

dispersion code

Bitterness level

CSDS01

CSDS02

CSDS03

CSDS04

CSDS05

*

***

****

****


Table 6.9.2.C.1:


Time (min)


CSDS03 CSDS04 CSDS05

0 5

10

15

20

25

30

35

DE10 (%)

DE30 (%)

T50 (min)

K1(min-1) r

0

71.45+1.25

75.64+1.33

84.03+1.74

89.16+1.74

94.45+0.89

97.38+1.36

99.07+0.83

54.64

77.24

5.88

0.1179

0.9807

0

73.78+1.47

79.75+1.46

86.12+1.35

92.78+1.23

96.11+1.05

99.05+1.36

---

56.83

79.68

5.15

0.1345

0.9749

0

76.11+1.73

80.16+1.47

88.73+1.35

94.55+1.62

98.05+1.74

99.42+1.52

---

58.10

81.22

4.46

0.1555

0.9822

339

Fig. 6.9.2.C.1A: Dissolution profiles of Fig. 6.9.2.C.1B: First order dissolution plots

ciprofloxacin HCl reconstituted dry syrups containing of ciprofloxacin HCl reconstituted

drug as solid dispersion prepared with stearic acid dry syrups containing drug as

and PEG 1500 on day 1 solid dispersion prepared with stearic acid

and PEG 1500 on day 1

Table 6.9.2.C.2:


0

20

40

60

80

100

120

0 10 20 30 40

% D

rug

rele

ase

Time (min)CSDS03 CSDS04 CSDS05

0.00

0.50

1.00

1.50

2.00

2.50

0 10 20 30 40

Log%

dru

g un

rele

ased

Time (min)CSDS03 CSDS04 CSDS05

Time (min)


CSDS04 CSDS05

0 5

10

15

20

25

30

DE10 (%)

DE30 (%)

T50 (min)

K1(min-1) r

0

71.27+1.36

78.09+1.83

84.24+1.24

90.68+1.62

94.37+1.18

96.73+0.72

55.16

77.84

6.75

0.1027

0.9807

0

74.11+2.21

81.79+1.48

87.10+1.52

92.51+1.58

96.12+0.84

97.64+0.77

57.50

80.08

6.09

0.1138

0.9813

340

Fig. 6.9.2.C2A: Dissolution profiles of Fig. 6.9.2.C2B: First order dissolution plots of


containing drug as solid dispersion prepared containing drug as solid dispersion prepared

with Stearic acid and PEG 1500 on day 7 with stearic acid and PEG 1500 on day 7


For each designated dry syrup formulation, blend of drug in a solid dispersion

form [Ciprofloxacin HCl: Stearic acid: PEG 1500; (1:1:0.8)] and excipients with different

concentrations of suspending agents, was prepared. In the CSDS01 formulation, pure

drug was formulated with 11.5 times of erythritol. There was no significant change in the

masking of bitter taste of the drug with 11.5 times of erythritol. Hence ciprofloxacin HCl

solid dispersion [Ciprofloxacin HCl: Stearic acid: PEG 1500; (1:1:0.8)] was used instead

of pure drug for formulations CSDS02 to CSDS05. CSDS02 is slightly in bitter taste in

comparison to CSDS03 to CSDS05. Formulations CSDS03 to CSDS05 constituted with

aspartame have absolutely masked the bitterness. Various concentrations of suspending

agents were added to formulations CSDS01 to CSDS05. After reconstitution, each dry

syrup formulation was evaluated for sedimentation volume, pH, specific gravity, drug

content and taste on day 1 & day 7. Results are shown in Tables 6.9.2.A & 6.9.2.B.

Percentage sedimentation volume was found to be between 74.5+0.82 to 80.2+1.02 on

day1 and 68.5+1.37 to 78.4+0.94 on day 7. Each sample of the formulation had good

020406080

100120

0 20 40

% D

rug

rele

ase

Time (min)

CSDS04 CSDS05

0.000.501.001.502.002.50

0 20 40

Log%

dru

g un

rele

ased

Time (min)

CSDS04 CSDS05

341

visual appearance and high sedimentation volume, which indicates that the solid

dispersion formed flocs.




below 4.74+0.04 and 4.51+0.05 to 4.52+0.04 on day 1 and day 7 respectively. Specific





98.26+1.38 to 98.88+1.20 & 96.31+1.63 to 96.58+1.32 of ciprofloxacin HCl on day 1

and day 7 respectively, which were within the acceptable limits.



The results of in vitro dissolution studies of various formulations, CSDS03 to CSDS05,

in 0.1 N HCl, are shown in Table 6.9.2.C.1 and in Figs. 6.9.2.C.1A & 6.9.2.C.1B on day

1. Day 7 results are shown in Table 6.9.2.C.2 and in Figs. 6.9.2.C.2A & 6.9.2.C.2B. All







342

6.9.2.C.2 on day 7. The percentage of drug dissolved from CSDS05 was to be more than

the other two formulations. CSDS05 has the more sedimentation volume with ease of

redispersibility and comparable drug release profile with CSDS04 formulation.The

dissolution rate constant (K1), half-life, DE10 and % DE30 for formulation CSDS05 were

0.1555 min-1, 4.46 minutes, 58.10 and 81.22% respectively on day 1. On day 7,

dissolution rate constant (K1), half-life, DE10% and DE30% for formulation CSDS05 were

0.1138 min-1, 6.09 minutes, 57.50 and 80.08% respectively.


bitter taste masking by procedure mentioned in chapter 6.1.3. CSDS01 was highly bitter

in taste. CSDS02 was slightly in bitter and CSDS03, CSDS04 & CSDS05 were no bitter

in taste for a period of 10 minutes. The healthy human volunteers participated in taste


grittiness of the dispersions soon after held in mouth. CSDS04 & CSDS05 showed

smooth and pleasant mouth feeling.


Preparation of solid dispersion of ciprofloxacin HCl with stearic acid and PEG

1500 by fusion method is a simple and efficient technique for masking of bitterness of the

drug. Dry syrup was prepared by passing all the ingredients through 60-mesh sieve.

Ciprofloxacin HCl dry syrup formulation was prepared by using erythritol & aspartame

as sweeting agents and sodium carboxymethyl cellulose & xanthan gum as suspending

agents at different concentrations with the drug in solid dispersion [Ciprofloxacin HCl:

Stearic acid: PEG 1500; (1:1:1)]. The formulated dry syrup was evaluated for drug

content, taste of the syrup after reconstitution, pH of the syrup, sedimentation volume,

343

specific gravity and dissolution characteristics. The sedimentation volume and

redispersiblity was more for the dry syrup containing 4.87% of sodium CMC (CSDS05).

The concentration and nature of the sodium CMC used in these solid dispersions

formulations drives desirable viscous that it helps more sedimentation volume with ease

of redispersibility and increased dissolution rate compare to other liuid formulations.The

dissolution of the drug from the reconstituted syrup follows first order kinetics. Thus the

technique of preparation of solid dispersion of ciprofloxacin HCl with stearic acid & PEG

gave dry syrup of pharmacopeial quality, pediatric patient palatability, convenient and

inexpensive.

344

6.10 Stability studies on selected ciprofloxacin HCl dry syrup

Stability studies are conducted to monitor the effect of different conditions

(temperature, humidity, light) on a material or on a batch over a given period of time.

Samples of the material or batch are stored under controlled environment conditions and

parts of the samples are inspected at selected time points throughout the study. In

pharmaceutical sense, stability is defined as the capability of a particular formulation, in a

specific container closure system, to remain within its physical, chemical,

microbiological, therapeutical and toxicological classification during its assigned shelf

life.

Liquid dosage forms (Dry syrup), apart from their other requirements, should be

stable with regard to their properties, especially their dissolution characteristics. The

stability of optimized, ciprofloxacin HCl dry syrup developed in the present study was

evaluated as per ICH guidelines. The storage conditions recommended by ICH for

stability testing are summarized in Table 6.10A.

The storage conditions for accelerated testing (as per ICH and WHO) are 40 ± 20

C and 75 ± 5% RH for 6 months. If the product is unstable in the above conditions

intermediate conditions (30 ± 20 C and 60 ± 5% RH) are recommended. WHO prescribed

testing at 0, 1, 2, 3 and 6 months during storage. ICH has not given testing time

frequency.

345

Table 6.10A: Recommended stability storage conditions for various products in zone I and II countries (ICH / US FDA Draft)

S.No. Product Accelerated Intermediate Long-term

1. Solid oral dosage forms, solids for

reconstitution, Dry and lyophilized

powders in vials.

40˚ C / 75% RH 30˚ C / 80% RH 25˚ C / 80% RH

2. Liquids in glass bottles, vials or

sealed glass ampoules which provide

an impermeable barrier to water loss

40˚ C / ambient

humidity

30˚ C / ambient

humidity

25˚ C / ambient

humidity

3. Drug products in semi-permeable

and permeable containers, large

volume parenterals (LVPs), small

volume parenterals (SVPs),

opthalmics, optics, and nasal sprays

packaged in semi permeable

containers such as plastic bags,

semi-rigid plastic containers,

ampoules, vials or bottles with or

without droppers / applicators which

may be susceptible to water loss.

40˚ C / 15% RH 30˚ C / 40% RH 25˚ C / 40% RH

4. Drug products intended to be stored

at refrigerator temperatures.

25˚ C / 60% RH

or 25˚C/ ambient

humidity for

liquid products

5˚C 3˚C

with

monitoring,

but not control

of humidity

5. Stability storage conditions for drug

products intended to be stored at

freezer temperature.

5˚ C 3˚ C /

ambient

humidity

-15˚ C 5˚ C

346

EXPERIMENTAL

Stability studies were carried out on the optimized formulation (CRDS04), as per

ICH guidelines. The dry syrup was packed in amboured colored bottle and stored at 400 C

and 75% RH for 6 months. During storage, the products were monitored for

sedimentation volume, pH of the formulation, specific gravity, drug content, taste, mouth

feel and dissolution profile studies were carried out at 3 and 6 months as per the methods

described earlier in chapter 6.4.2. The results are given in Tables 6.10B & 6.10C and

shown in Figs. 6.10C1 and 6.10C2.

Table 6.10B: Evaluation of physicochemical parameters of selected ciprofloxacin HCl

dry syrup before and during storage at 40 2˚C/75 5% RH

6. Stability storage conditions for some

inhalation products.

Additional storage conditions may apply to

inhalation powders and suspension inhalation

alcohols when significant change in aerodynamic

particle size distribution or in dose content

uniformity occurs at accelerated conditions (40˚ C

/ 75% RH ) conditions being satisfied.

Paramèters

Accelerated stability studies at 40 ± 20 C and 75 ± 5% RH (x s.d.,n=3)

Before storage

After 3 months storage

After 6 months storage

Significance of difference

Sedimentation volume

pH of the formulation

Specific gravity

(%) Drug content

DE10 (%)

DE15 (%)

79.5+1.20

4.42+0.03

1.13+0.04

98.34+1.34

63.79+0.96

73.73+0.43

76.9+0.74

4.47+0.05

1.14+0.04

97.12+1.35

62.69+1.48

72.46+0.64

75.4+0.80

4.52+0.03

1.14+0.03

96.12+0.52

61.62+0.42

71.25+0.58

P= 0.0710

P=0.0794

P=0.8026

P=0.1746

P=0.1001

P=0.0511

347

Table 6.10C: Release profiles of ciprofloxacin HCl dry syrup before and

during storage for 6 months at 40 2˚ C /75 5%RH

Fig. 6.10C1: Dissolution profiles of Fig. 6.10C2: First order dissolution plots of

ciprofloxacin HCl dry syrup before and ciprofloxacin HCl dry syrup before and

after storage for 6 months at after storage for 6 months at

40 2˚C / 75 5%RH 40 2˚C / 75 5%RH

0

50

100

150

0 5 10 15 20 25

% D

rug

rele

ase

Time (min)

Before storage After 3 monthsAfter 6 months

-0.50

0.00

0.50

1.00

1.50

2.00

2.50

0 5 10 15 20 25

Log%

dru

g un

rele

ased

Time (min)

Before storage After 3 monthsAfter 6 months

Time (min)

Cumulative % of ciprofloxacin HCl released

Before storage After storage 3 Months 6 Months

0

5

10

15

20

DE10 (%)

DE15 (%)

T50 (min)

K1(min-1) r

0

82.56+2.36

90.05+1.28

97.18+1.48

99.39+0.72

63.79+0.96

73.73+0.43

2.88

0.2404

0.9900

0

81.14+1.73

88.48+2.02

95.52+0.93

97.85+0.66

62.69+1.48

72.46+0.64

3.80

0.1824

0.9818

0

79.87+1.69

86.75+1.45

94.25+1.12

96.42+0.81

61.62+0.42

71.25+0.58

4.38

0.1582

0.9702

348


The dry syrup prepared by the optimized formulation (CRDS04), was charged on

accelerated stability and monitored for sedimentation volume, pH of the formulation,

specific gravity, drug content, taste, mouth feel and dissolution profile studies, at 40 ±

2°C / 75 ± 5 % RH for 6 months. Physical observation and drug release studies were

conducted after 3 months of storage and after 6 months of storage. The stability study

reveals no significant variation in sedimentation volume, pH of the formulation, specific

gravity, drug content, taste, mouth feel and in vitro dissolution study up to three and six

months. Statistical analysis was done by paired t-test, to verify whether the differences

observed between the physical parameters before and after during storage at 40 2°C

and at 755% relative humidity (RH), for in 6 months period, were significant or not. No

significant difference was observed in any one of all the cases (P>0.05). The results are

shown in Table 6.10B. CRDS04 showed tasteless, smooth and pleasant mouth feeling

after 6 months of storage. The drug release profiles of the formulations containing

Ciprofloxacin HCl before and after storage are shown in Table 6.10C and in Figs.

6.10C1 & 6.10C2. The results thus indicated that the formulation was stable under

accelerated conditions of temperature and humidity.

349

6.11 PHARMACOKINETIC EVALUATION OF FORMULATED

CIPROFLOXACIN HCl DRY SYRUP AND COMMERCIAL PRODUCT

In vivo pharmacokinetic studies were carried out on the following products.

1. Reference formulation:

Cifran 100 tablets (100 mg of ciprofloxacin HCl per tablet, M/s Macleods

Pharmaceuticals Ltd. Solan, H.P) purchased from local market.

2. Test formulation:

Formulation CRDS04 containing 100 mg of ciprofloxacin HCl per 5 ml of

reconstituted dry syrup.

In vivo experiments were carried out in healthy rabbits as per the following

experimental design and protocol.

Experimental design:

In the present study, in vivo animal studies of test formulation and commercial

product were performed in healthy rabbits of either sex weighing (1.0 ± 0.2 kg) were

divided into 2 groups, each consisting of 6 animals. First group received Cifran 100

tablets (reference) and second group received the test formulation (CRDS04). Food was

withdrawn from the rabbits 12 hrs before drug administration and until 24 hrs post

dosing. All rabbits had free access to water throughout the study. Animal housing and

handling were in accordance with the CPCSEA guide lines. This study on animals were

carried out in the pharmacology laboratories of the University College of Pharmaceutical

Sciences, Andra university, which is approved by the institutional ethics committee and

CPCSEA (Regd. No. 516 – 01/ A/ CPCSEA) for experimentation on animals.

350

In vivo study protocol

After collecting the zero hour blood sample (blank), the products involved in the

study was administered orally at a dose equivalent to 30 mg of ciprofloxacin HCl/kg of

body weight of rabbit. 2 ml of blood samples were collected from the marginal ear vein at

0.5, 1.0, 2.0, 3.0, 4.0 5.0 and 6.0 hrs after administration of the product. The blood

samples were centrifuged at 4,000 rpm and and the separated plasma samples were stored

at -20°C until analysis.

Extraction procedure of Ciprofloxacin HCl from rabbit plasma

To 0.5 ml of plasma, 1 ml of ACN was added in to 1.5 ml of poly propylene

tubes. The tubes were vortex-mixed for 5 minutes in cyclomixer and then centrifuged for

10 min. at 4000 rpm. The upper organic layers of the tubes were collected, filtered and

injected into the column and then analyzed by using a sensitive high-performance liquid

chromatography (HPLC) assay method discussed in Chapter 6.1.2.

Ciprofloxacin HCl concentrations in plasma following the administration of

commercial and experimental products are given in Tables 6.11.1 & 6.11.2 and are

shown in Figures 6.11.1 & 6.11.2. From time versus plasma concentration data, various

pharmacokinetic parameters such as peak concentration (C max), time at which peak

concentration occurred (Tmax), area under the curve (AUC), elimination rate constant

(Kel), biological half - life (t 1/2) and mean residence time (MRT) were calculated in each

case. The results are given Table 6.11.3.

351

DETERMINATION OF PHARMACOKINETIC PARAMETERS

Cmax, Tmax, elimination rate constant (Kel), biological half-life (t1/2), percentage

absorbed at various times, absorption rate constant (Ka), AUC and MRT are determined

as procedure mentioned in chapter 5.11.

Table 6.11.1: Plasma concentrations of ciprofloxacin HCl following oral

administration of commercial tablets (Cifran 100) to six healthy rabbits

Plasma Concentration (µg/ml) Time (hrs)

Subjects 1 2 3 4 5 6 Mean SD CV%

0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.50 8.65 7.99 8.27 8.56 8.12 8.87 8.41 0.34 4.01 1.00 11.98 13.04 12.36 12.42 11.96 12.58 12.39 0.40 3.25 2.00 16.15 16.87 17.27 16.41 16.46 15.64 16.47 0.56 3.43 3.00 17.87 18.24 18.52 18.15 19.14 17.23 18.19 0.64 3.53 4.00 18.56 18.83 19.09 18.92 19.70 18.33 18.91 0.47 2.49 5.00 15.02 14.38 16.40 15.84 15.96 14.86 15.41 0.77 5.02 6.00 12.56 13.40 14.41 13.55 12.42 11.56 12.98 1.01 7.75

Table 6.11.2: Plasma concentrations of ciprofloxacin HCl following oral

administration of experimental formulation (CRDS04) to six healthy rabbits

Plasma Concentration (µg/ml) Time (hrs)

Subjects 1 2 3 4 5 6 Mean SD CV%

0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.50 9.84 9.47 9.74 10.00 9.67 9.96 9.78 0.20 2.03 1.00 13.35 13.11 12.71 12.89 13.41 13.00 13.08 0.27 2.07 2.00 16.51 17.44 16.77 17.83 17.34 17.77 17.28 0.53 3.09 3.00 18.57 19.43 18.92 18.72 18.88 19.58 19.02 0.40 2.12 4.00 19.78 20.27 20.05 19.89 20.05 20.44 20.08 0.24 1.21 5.00 19.19 17.69 16.80 17.63 17.02 18.01 17.72 0.85 4.80 6.00 16.51 16.05 14.20 16.11 15.51 16.54 15.82 0.88 5.54

352

Fig. 6.11.1: Time Vs plasma concentration Fig. 6.11.2: Time Vs Log percent drug unabsorbed

curves of ciprofloxacin HCl following oral plot of ciprofloxacin HCl following oral

administration of commercial tablets administration of commercial tablets (Cifran 100)

(Cifran 100) and experimental formulation and experimental formulation (CRDS04)

(CRDS04) in rabbits in rabbits

Table 6.11.3: Pharmacokinetic parameters of ciprofloxacin HCl following oral administration of

commercial tablets (Cifran 100) and experimental formulation (CRDS04) to rabbits

Pharmacokinetic parameter

Commercial product

(Cifran 100)

Experimental formulation (CRDS04)

Test of significance

Cmax(µg/ml) 18.91 20.08 N.S.

Tmax(hr) 4.0 4.0 N.S.

Ke(hr-1) 0.188 0.119 N.S.

Ka(hr-1) 0.637 0.675 N.S.

AUC0-6(µg hr ml-1) 88.87 96.67 N.S.

AUC0-∞(µg hr ml-1) 157.97 229.40 N.S.

MRT0-6(hr) 3.28 3.32 N.S.

MRT0-∞(hr) 6.80 9.72 N.S.

AUMC0-6(µg hr ml-1) 291.06 320.75 N.S.

AUMC0-∞(µg hr ml-1) 1073.47 2230.79 N.S.

Half life (t1/2) 3.69 5.82 N.S

Percent Absorbed in 3.0 hr 85.97 87.75 N.S.

0

5

10

15

20

25

0 2 4 6 8

Conc

entr

atio

n (µ

g/m

l)

Time (hrs)

Cifran 100

CRDSO4

0

0.5

1

1.5

2

2.5

0 1 2 3 4

Log%

dru

g un

abs

orbe

d

Time (hrs)

Cifran 100CRDSO4

353


As per in vivo study protocol, ciprofloxacin HCl products were administered per

orally to healthy rabbits at a dose equivalent to 30 mg of ciprofloxacin HCl/kg of body

weight of rabbit and the plasma concentrations were determined by HPLC method.

Pharmacokinetic parameters were determined, after the oral administration of

Cifran 100 tablets, absorption rate constant ka was found to be 0.637 hr-1, elimination rate

constant kel was found to be 0.188 hr-1 and the corresponding biological half-life (t1/2) was

found to be 3.69 hours. The MRT was found to be 6.80 hours. A peak plasma

concentration of 18.91 µg/ml was observed at 4.0 hours after administration of Cifran

100.

When the experimental CRDS04 formulation was administered orally, peak

concentration of 20.08 µg/ml was observed at 4.0 hours. The elimination rate constant kel

for ciprofloxacin HCl was found to be 0.119 hr-1, and the corresponding biological half

life (t1/2) was found to be 5.82 hours. The MRT was found to be 9.72 hr. The absorption

rate constant (ka) was found to be 0.675 hr-1.

AUC0-∞ and AUMC0-∞ were found to be 157.97 µg hr ml-1 and 1073.47 µg hr ml-1

respectively, for Cifran 100 and 229.40 µg hr ml-1 and 2230.79 µg hr ml-1 respectively,

for formulation CRDS04. AUC0-∞ (extent of absorption) and AUMC0-∞ were much higher

in the case of formulation, CRDS04 when compared to Cifran 100.

Pharmacokinetic parameters of absorption (Table 6.11.3) namely Ka, Cmax, Tmax,

and percent absorbed at 3.0 hr indicated similar absorption and bioavailability of

experimental formulation (CRDS04) with commercial formulation (Cifran 100).

354

Student’s t-test was performed to test the significant differences if any between

the pharmacokinetic parameters of experimental formulation (CRDS04) and commercial

formulation (Cifran 100). The pharmacokinetic data was subjected to statistical analysis

(P<0.05). The results of statistical analysis indicated no significant difference in Cmax,

Tmax, Ka, Ke, t1/2, MRT, percent absorbed at 2.0 hr, AUC and AUMC values among

Cifran 100 and CRDS04. So, it may be concluded, that the test formulation (CRDS04) of

ciprofloxacin HCl is having similar absorption and bioavailability in comparison with the

commercial product (Cifran 100) and it shows more superior in its palatability due to

drug resin complex of ciprofloxacin HCl with Indion 414.

COMPARISON WITH PAST WORK

Robin L.Davis et al (1985)1 compared the absorption of three formulations of

ciprofloxacin after oral administration in 18 normal adult male volunteers. Each subject

received 500 mg of ciprofloxacin as two 250 mg tablets, one 500 mg tablet, or a solution

in a randomized crossover sequence. Mean values for the maximum concentration of

drug in serum, the time to maximum concentration of drug in serum, and the elimination

half-life were 3.23 ug/ml, 1.00 hrs and 5.04 h, respectively, for the solution.

In present work, pharmacokinetic studies were studied on the developed,

optimized ciprofloxacin HCl dry syrup (CRDS04) in comparison with Cifran 100 tablets

with dose of 30 mg of ciprofloxacin HCl /Kg of body weight in rabbits. Cmax, T max and

t1/2 of the experimental ciprofloxacin HCl dry syrup (CRDS04) were more in rabbits

when compared to above cited work in humans.

355


Pharmacokinetic studies were carried out on the developed, optimized

reconstituted dry syrup (CRDS04) in comparison with Cifran 100 tablets. CRDS04

contains 100 mg of ciprofloxacin HCl per 5 ml of suspension and each Cifran 100 tablets

contains 100 mg. As per in vivo study protocol, ciprofloxacin HCl products were

administered per orally to healthy rabbits at a dose equivalent to 30 mg of ciprofloxacin

HCl/kg of body weight of rabbit and the plasma concentrations were determined by

HPLC method. All the pharmacokinetic parameters of absorption, namely, Ka, Cmax, Tmax,

and percent absorbed at 3.0 hr indicated similar absorption and bioavailability of

experimental formulation (CRDS04) with that of commercial formulation (Cifran 100).

AUC0-∞ and AUMC0-∞ were found to be 157.97 µg hr ml-1 and 1073.47 µg hr ml-1

respectively, for Cifran 100 and 229.40 µg hr ml-1 and 2230.79 µg hr ml-1 respectively,

for formulation CRDS04. AUC0-∞ (extent of absorption) and AUMC0-∞ were much higher

in the case of formulation, CRDS04 when compared to Cifran 100. So, it may be

concluded, that the test formulation (CRDS04) of ciprofloxacin HCl is having similar

absorption and bioavailability in comparison with the commercial product (Cifran 100)

and it shows more superior in its palatability due to drug resin complex of ciprofloxacin

HCl with Indion 414.

REFERENCE

1. Robin L. Davis, Jeffrey R. Koup, Judy Williams-Warren, Allan Weber and Arnold L.

Smith; Pharmacokinetics of three oral formulations of Ciprofloxacin. Antimicrobial

Agents and Chemotherapy. (1985), 28(1): 74-77.

Documents

CHAPTER VI 6.1 ANALYTICAL METHODSshodhganga.inflibnet.ac.in/bitstream/10603/12764/18... · Ciprofloxacin HCl is official in IP 20071 , B.P 2 and USP 24/NF 193. A number of methods