LABORATORY PREPARATION AND EVALUATION OF BENTONITE …

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Rina et al. World Journal of Pharmacy and Pharmaceutical Sciences

LABORATORY PREPARATION AND EVALUATION OF BENTONITE

CLAY SOAP AND ITS COMPARISON WITH THE MARKETED

PREPARATIONS

Rina Maskare1*, Bhumesh Wanjari

2, Kirti Nanhe

3, Jyoti Shivankar

4 and Karishma

Tikariya5

1Mahoharbhai Patel Institute of B-Pharmacy, Gondia, Masharashtra.

2Gondia College of Pharmacy, Gondia.

3Birla Institute of Technology and Science, Pilani Campus, Pilani.

4,5Mahoharbhai Patel Institute of D-Pharmacy, Gondia, Masharashtra.

ABSTRACT

Bentonite clay soap was formulated using Bentonite clay. The prepared

formulation and its marketed preparations were evaluated for various

physicochemical parameters such as colour, odour, appearance, tex-

ture, hardness, pH, foam height, foam retention, % free alkali, alcohol

insoluble matter, emulsification test, moisture content, high tempera-

ture stability and total fatty matter for which good characteristics were

observed. The antimicrobial efficacy of the prepared formulation and

its marketed preparations was tested using agar well diffusion method

against the organisms E.coli and S. aureus. By comparing prepared

formulation with its marketed preparations, it was found that the pre pared bentonite clay

soap has good parameters as compared to its marketed preparations. Hence owing to accepta-

ble parameters and good antimicrobial effect, the prepared formulation can be standardized

and used as effective medicated bathing soap.

KEYWORDS: Bentonite clay saop, pH, TFM, Medicated soap.

INTRODUCTION

Soap may be defined as water-soluble salt of fatty acids which contain more than eight car-

bon atoms.[1]

Saponification is a process in which fat molecule is broken down by sodium hy-

droxide (lye) into four smaller molecules are soap and one is glycerol. In simple terms sapon-

WORLD JOURNAL OF PHARMACY AND PHARMACEUTICAL SCIENCES

SJIF Impact Factor 7.632

Volume 10, Issue 1, 948-959 Research Article ISSN 2278 – 4357

*Corresponding Author

Rina Maskare

Mahoharbhai Patel Institute

of B-Pharmacy, Gondia,

Masharashtra.

Article Received on

23 October 2020,

Revised on 13 Nov. 2020,

Accepted on 03 Dec. 2020

DOI: 10.20959/wjpps20211-17985


949


ification is the name for a chemical reaction between an acid and a base to form a salt. An

acid is a molecule or ion that donates protons or hydrogen ions (H+) and/or accepts electrons,

and a base is any substance that donates electrons or hydroxide ions (OH-) and/or that accepts

protons. When you make a soap, you mix an oil or fat (which is your acid) with sodium hy-

droxide or Lye (which is your base) to form soap (which is a salt). There are many different

types of acids that will react with your base and saponify. Your acid could be olive oil, coco-

nut oil or vegetable oil just to name a few. Each acid has a unique combination of triglycer-

ides (compound made of three fatty acids attached to a single glycerol molecule) which com-

bines with the base (sodium hydroxide or lye) differently.[2]

Healing clays, like Bentonite Clay, bind to heavy metals in the body and help to remove

them. This same action can happen externally, and clay is often added to baths for detoxing.

Bentonite Clay is a unique clay due to its ability to produce an “electrical charge” when hy-

drated. Upon contact with fluid, its electrical components change, giving it the ability to ab-

sorb toxins. Bentonite is known for its ability to absorb and remove toxins, heavy metals, im-

purities, and chemicals. Bentonite is a swelling clay when it becomes mixed with water it

rapidly swells open like a highly porous sponge. From here the toxins are drawn into the

sponge through electrical attraction and once there, they are bound. Bentonite clay is great

clay that can be added to soap. It also has an amazing capacity to absorb toxins from the body

making it great for oily and acne-prone skin. It is composed of volcanic ash and is a light

gray color but will add an almost greenish tint to your soap.

This montmorillonite Clay is considered a powerful, yet gentle detoxifier with an alkalinity of

8.5pH. This clay is ultra-pure, clean, allergen free and high in beneficial trace elements, mak-

ing it the clay of choice for internal use. For general health maintenance take a heaped tea-

spoon (nonmetal) once a day in a glass and add spring water. Let rest for a few hours or over-

night. Drink on an empty stomach. Take for a period of 3 weeks with a one week break after;

continue this process for 3 months.

Montmorillonite clay are bentonite clays and bentonite clays are montmorillonite clays. They

are not two separate minerals as we thinks. They are one and the same thing. All types of

bentonite clays are grouped together under the montmorillonite or sectile group of clay. To

speak of one is to speak of the other.


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Montmorillonite was named after its discovery locality, Montmorillonite, France in the

1800’s. Bentonite was named after fort Benton, near which it was discovered.

MATERIAL AND METHODS

Preparation of bentonite clay soap

Solidified basic glycerin soap was broken down to smaller pieces and melted on water bath.

3.75 g of bees wax added to the melted soap.3.0 grams of bentonite clay powder was added to

the melted soap along with 5ml of ethanol. 0.33 g of stearic acid, 1ml each of cinnamon oil

and lemongrass oil was added to the melted soap. 0.02 g of borax and 0.2 ml triethanolamine

were added to the melted soap. The melted soap was gently mixed for about 30 minutes after

that add 0.1 ml perfume in it and moulded in specific mould. The soap was allowed to solidi-

fy at room temperature until set and kept under physical observation for any characteristic

changes.

Table No. 1: Formulation of bentonite clay soap.

Sr. No. Ingredients Quantity taken (g)

1 Bentonite Clay 3.0

2 Stearic Acid 0.33

3 Bees Wax 3.75

4 Borax 0.02

5 Ethanol 5.0

6 Triethalonamine 0.2

7 Cinnamon Oil 1.0

8 Lemongrass Oil 1.0

9 Perfume 0.1

10 Solid Basic Glycerine Soap q.s to 75.0

Evaluation

Physiochemical evaluation of prepared bentonite clay soap and its marketed soap

Physicochemical parameters like colour, odour, appearance, texture, hardness, pH, foam

height, foam retention, % free alkali, alcohol insoluble matter, high temperature stability,

moisture content, emulsification test, total fatty matter and antimicrobial activity were evalu-

ated.[3]

Hardness of soap: The hand feel hardness was determined relative to each other.

pH: The pH of all the prepared and marketed bentonite clay soap was determined by using

universal pH paper. The formulations were dissolved in 100 ml of distilled water. Use a glass


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stirring rod to place a drop of the soap solution on a piece of universal pH paper to determine

whether the solution is alkaline, neutral or acid.

Foam height: 0.5 gm of sample of soap was taken, dispersed in 25 ml distilled water. Then

transferred it into 100 ml measuring cylinder, volume was make up to 50 ml with water. 25

strokes were given and stand till aqueous volume measured up to 50 ml and measured the

foam height, above the aqueous volume.

Foam retention: 25ml of the 1% soap solution was taken into a 100 ml graduated measuring

cylinder. The cylinder was covered with hand and shaken 10 times. The volume of foam at 1-

minute intervals for 4 minutes was recorded.

Determination of percentage free alkali: About 5 gm of sample was taken in a conical flask

and added to it into 50 ml of neutralized alcohol. It was boiled under reflux on a water bath

for 30 minutes, cooled and 1 ml of phenolphthalein solution was added. It was then titrated

immediately with 0.1 N HCL.

Alcohol insoluble matter: 5 gm of sample was taken in a conical flask. Added it to 50 ml of

warm ethanol and shaken vigorously to dissolve. The solution was filtered through a tarred

filter paper with 20 ml warm ethanol and dried at 105°C for 1 hour. The weight of dried pa-

per was taken.

Formula

% alcohol insoluble matter = Wt. of residue x 100/ Wt. of sample

High Temperature Stability: The prepared soap and marketed soaps were allowed to stand

at different temperatures and the stability of soaps was observed.

Moisture content: Moisture content was determined by drying 10g of the sample to a con-

stant weight at 105°C according to AOAC. 4

It was allowed to cool and then reweighed. The

% moisture content was calculated from the formula below;

% Moisture content = W1/W2 x 100

Where

W1 = weight of soap after drying

W2 = weight of soap before dryings


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Emulsification test: 4 drops of mineral oil (gas oil) was taken into test tube, 5ml of the soap

solution was added to the oil in the test tube. The mixture in the test tube was shaken briefly

and the extent of emulsification was noted.[5]

Determination of total fatty matter (TFM): About 5g of the soap sample was dissolved in

water and the solution is treated with dilute sulphuric acid. The soap decomposed in to sodi-

um sulphate and fatty acids. The fatty acids so formed are separated by adding known quanti-

ty of bees wax in hot solution so that fatty acids get impregnated in bees wax. Fatty acid resi-

due in water was extracted by the technique of solvent extraction using Chloroform. Organic

layer was combined with layer of wax and so that total fatty acid content was impregnated in

wax, after cooling increase in weight of bees wax noted. From this TFM value was calculat-

ed.[6]

Weight of Wax Layer (having fatty matter)

=Weight of wax containing beaker –Weight of Empty Beaker = X (say)

Quantity of Bees Wax Added = Y (say),

Weight of Fatty Matter = X-Y

Total % of Fatty Matter = X-Y/Z x 100

Where, Z = Quantity of Soap utilized in experiment.

Antimicrobial testing of the prepared Bentonite clay soap and its marketed prepara-

tions: The prepared Bentonite clay soap and marketed preparations were subjected to antimi-

crobial screening by agar well diffusion method.

Table 2: List of marketed soap.

Sr.

No.

Code

Formula Brand Name Mfg Date Batch No.

1 BCS Prepared Bentonite Clay 03/18 -

2 MS1 Patanjali 11/17 ABC178

3 MS2 Naturma 07/17 1001N104

4 MS3 Fuschia 07/17 -

5 MS4 Akshaya’s 01/18 MMP0038

6 MS5 Mother Organic 04/18 -

7 MS6 Ancient Living 03/18 MS 060

Preparation of media: The media of nutrient agar was prepared in a sterile condition for an-

timicrobial bioassay.


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Table 3: Preparation of nutrient agar.

Ingredients Quantity (g)

Peptone 10.0

Sodium chloride 10.0

Beef extract 5.0

Agar 20.0

Distilled water 1000

pH adjusted 7.2

Resulting solution was sterilized and cooed first at room temperature and then at low temper-

ature, so that media sets into gel like mass. In agar plate small hole was punched with sterile

borer known as “well”. With the help of sterile Platinum Loop colony of E.coli and S.aureus

were spread on different agar medium. Organisms used were E. coli and S. aureus. One gram

of soap was mixed with 5ml of sterile water and used for evaluating the antimicrobial activi-

ties. The plates were incubated at 37°C for 24 hours and zones of inhibition were recorded.

RESULT AND DISCUSSION

Preparation of bentonite clay soap

Bentonite clay soap was prepared successfully by using Bentonite clay along with Cinnamon

oil and Lemongrass oil. The picture is shown in figure 1 and figure 2.

Figure no. 1: Bentonite clay soap along with Mould.

Figure no. 2: Bentonite clay soap


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Evaluation of prepared bentonite clay Soap and Marketed soap

The physicochemical parameters of the prepared bentonite clay soap and marketed preparations were determined. The results of evaluation pa-

rameter is tabulated in table no. 4.

Table 4: Physiochemical evaluation parameter of Bentonite clay soap and marketed soap.

Sr.

No.

Formu-

lations

Appear-

pear-

ance

Colour Odour Hard

ness Texture pH

Foam

Height

(cm)

Foam

Reten

ten-

tion

(min)

%

Free

Alkali

Alcohol

insoluble

matter

(%)

High Tem-

perature

Stability

Moisture

Content

(%)

Total

Fatty

Matter

(%)

01. BCS1 Good Brown Fragrant Soft Solid and

Smooth 07 6.7 10.0 0.27 23.2

Melts above

60°C 6.8 67.8

02. MS1 Good Light

brown Fragrant Hard

Solid and

Smooth 08 6.6 12.0 0.32 19.8

Melts above

60°C 3.0 62.2

03. MS2 Good Red Fragrant Soft Solid and

Smooth 07 6.3 08.0 0.29 13.0

Melts above

60°C 3.2 64.4

04. MS3 Good Orange Fragrant Soft Solid and

Smooth 06 6.2 09.0 0.31 10.2

Melts above

60°C 7.2 63.4

05. MS4 Good Brown Fragrant Hard Solid and

Smooth 08 4.5 07.0 0.28 15.4

Melts above

60°C 4.2 65.6

06. MS5 Good Brown Fragrant Soft Solid and

Smooth 07 4.8 11.0 0.33 03.0

Melts above

60°C 11.2 66.8

07. MS6 Good Cream Fragrant Hard Solid and

Smooth 08 6.5 06.0 0.30 03.0

Melts above

60°C 13.6 61.6


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The formulations exhibited good appearance characteristics as well as the pH was found in

the range of 6.0 to 8.0 which is the desired pH. The pH of prepared bentonite clay soap and

marketed preparations were tabulated in table no.4 and comparison between them shown in

figure no 3.

Figure no 3: Physiochemical evaluation parameter of Bentonite clay Soap and

Marketed soap.

Checking the pH of soap is necessary not only for the purpose of improving soaps quality but

to regulate the pH level which shall not contribute to the hardness of hands and skin. For the

purpose of protecting public health, high pH levels in the 9 to 11 range or low in 3 to 5 level

are considered deleterious to the skin. This is in accordance with NAFDAC regulatory re-

quirements on cosmetics, soap and detergents. This high value is due to incomplete alkali hy-

drolysis resulting from the saponification process fat or oil or any other superfatting agent to

reduce the harshness of the soap. This indicates that, the prepared soap is not corrosive to the

skin. As the salt of a weak acid (fatty acid) and strong base (NaOH), soap is alkaline (pH~10)

in aqueous solution. Alkaline substances neutralize the body’s protective acid mantle that acts

as a natural barrier against bacteria and viruses. Healthy skin has a pH 5.4 to 5.9. The alkalin-

ity favours detergency.

The foam height, foam retention, % free alkali, alcohol insoluble matter, high temperature

stability, moisture content of prepared bentonite clay soap and marketed preparations were

tabulated in table no. 4 and comparison between them shown in figure 3. In the emulsifica-

tion test of prepared Bentonite clay soap and marketed preparation show good emulsification.


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TFM shows how much fat substance the soap has, i.e., it is the indication of soap quality. If

the TFM is more, better the quality of soap. The lower TFM value is due to presence of unre-

acted Sodium hydroxide in the mixture. However, dry skin needs soap which is high in TFM

80%. This re-hydrates the skin making it smooth, and additionally the high oil content within

the sop acts as a lubricant trough out the day. TFM values of prepared bentonite clay soap

and marketed preparations tabulated in table no.4 and comparison between them represented

in figure 3. TFM values of formulations were 61.6% to 67.8%. According to BIS norms such

soaps can be categorized as Grade III soaps and it can be used for general bathing purpose.

The antimicrobial activity of soap samples by well diffusion method against microorganisms

such as Escherichia coli and Staphylococcus aureus were performed and the diameter zone of

inhibition was tabulated in table no.5 and shown in figure no. 4 and figure no 5.

Table 5: The result of Antimicrobial activity of Bentonite clay soap and marketed soap.

Sr. No. Formula-

tions

Diameter zones of inhibition in mm

E. coli S. aureus

1 BCS 18 16

2 MS1 11 02

3 MS2 12 14

4 MS3 10 06

5 MS4 14 06

6 MS5 12 09

7 MS6 11 11

Figure no. 4: Antimicrobial activity of Bentonite clay soap against E.coli.


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Figure no. 5: Antimicrobial activity of bentonite clay soap against S. aureus.

The Bentonite clay based medicated soap demonstrated an excellent antimicrobial activity

against the tested microbial skin flora. The medicated soap was active against bacteria like

staphylococcus aureus and Escherichia coli. Comparison of Antimicrobial activity of pre-

pared Bentonite clay soap and marketed preparations was shown in figure 6.

Figure no. 6: Comparison of Antimicrobial activity of prepared Bentonite clay soap and

marketed preparations.

CONCLUSION

Bentonite clay was selected for the study. The bentonite clay soap was prepared through melt

and pour method by standard procedure using bentonite clay, solidified basic glycerine soap,

cinnamon oil and lemongrass oil. Physicochemical parameters such as color, odour, texture,

pH, TFM, Moisture content, hardness and foam test (foam height, foam retention), emulsifi-

cation test free alkali alcohol insoluble matter were evaluated. These parameters will serve as

standardization of the bentonite clay soap. Evaluation of antimicrobial activity such as deter-


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mination of anti-bacterial activity (S.aureus, E.coli) was performed on the bentonite clay soap

and the result shows the soap has got considerably good antimicrobial property. The prepared

bentonite clay soap was found to be good medicated bathing soap by comparing physico-

chemical parameters with its marketed preparations.

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LABORATORY PREPARATION AND EVALUATION OF BENTONITE …