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Section – (i): Introduction to analytical techniques
Chemistry is the study of matter, including its composition and structure, its physical
properties, and its reactivity. There are many ways to study chemistry, but, we traditionally
divide it into five fields: Organic chemistry, Inrorganic chemistry, Biological chemistry, Physical
chemistry, and Analytical chemistry. Analytical chemistry is often described as the area of
chemistry responsible for characterizing the composition of matter, both qualitatively (Is there
any lead in this sample?) and quantitatively (How much lead is in this sample?). Most chemists
routinely make qualitative and quantitative measurements. For this reason, some scientists
suggest that analytical chemistry is not a separate branch of chemistry, but simply the application
of chemical knowledge. Defining analytical chemistry as the application of chemical knowledge
ignores the unique perspective that analytical chemists bring to the study of chemistry.
Analytical chemistry is what analytical chemists do [1]. The craft of analytical chemistry is not
in performing a routine analysis on a routine sample, which more appropriately is called
chemical analysis, but in improving established analytical methods, in extending existing
analytical methods to new types of samples, and in developing new analytical methods for
measuring chemical phenomena. A more appropriate description of analytical chemistry is “the
science of inventing and applying the concepts, principles, andstrategies for measuring the
characteristics of chemical system.
Analytical chemists typically operate at the extreme edges of analysis, extending and
improving the ability of all chemists to make meaningful measurements on smaller samples, on
more complex samples, on shorter time scales, and on species present at lower concentrations.
Throughout its history, analytical chemistry has provided many of the tools and methods
necessary for research in the other traditional areas of chemistry. A recent editorial on Analytical
Chemistry entitled “Some Words about Categories of Manuscripts” nicely highlights what makes
a research endeavor relevant to modern analytical chemistry [2]. Many analytical chemists
describe this perspective as an analytical approach to solving problems [3-6].Analytical
chemistry is the study of the separation, identification, and quantification of
the chemical components of natural and artificial materials [7]. Qualitative analysis gives an
indication of the identity of the chemical species in the sample, and quantitative
analysis determines the amount of certain components in the substance. The separation of
components is often performed prior to analysis.Analytical methods can be separated into
classical and instrumental [8]. The first instrumental analysis was flame emissive spectrometry
developed by Robert Bunsen and Gustav Kirchhoff who discovered rubidium (Rb)
and caesium (Cs) in 1860 [9].The separation science techniques were discovered in the early
20th century and refined in the late 20th century and also become increasingly transformed into
high performance instruments [10].Classical methods (also known as wet chemistry methods)
use separations such as precipitation, extraction, distillation and qualitative analysis by color,
odor, or melting point. Quantitative analysis is achieved by measurement of weight or volume.
Instrumental methods use an apparatus to measure physical quantities of the analyte such as light
absorption, fluorescence, or conductivity. The separation of materials is accomplished
using chromatography, electrophoresis or field flow fractionation methods.
An analytical technique is a method that is used to determine the concentration of
a chemical compound or chemical element. There are a wide variety of techniques used for
analysis, from simple weighing (gravimetric analysis) to titrations (titrimetric) to very advanced
techniques using highly specialized instrumentation. There are many more techniques that have
specialized applications, and within each major analytical technique there are many applications
and variations of the general techniques.From the stages of drug development to marketing and
post marketing, analytical techniques play a great role, be it understanding the physical and
chemical stability of the drug, impact on the selection and design of the dosage form, assessing
the stability of the drug molecules, quantitation of the impurities and identification of those
impurities which are above the established threshold essential to evaluate the toxicity profiles of
these impurities to distinguish these from that of the active pharmaceutical ingredient (API). The
analysis of drug and its metabolite which may be either quantitative or qualitative is extensively
applied in the pharmacokinetic studies.
1.0 Types of analytical techniques being used in pharmaceuticals
The following are the various analytical techniques which are being used in qualitative
and quantitative analysis of drug substances and drug products in a pharmaceutical industry.
1.1 Titrimetric techniques
1.2 Chromatographic techniques
1.3 Spectroscopic techniques
1.4 Electrochemial techniques
1.5 Kinetic method of analysis
1.6 Electrophoretic methods
1.7 Flow injection and sequential injection analysis
1.8 Hyphenated techniques
1.1 Titrimetric techniques
Origin of the titrimetric method of analysis goes back to somewhere in the middle of the
18th century. It was the year 1835 when Gay–Lussac invented the volumetric method which
subsequently lead to the origin of the term titration. Although the assay method is very old yet
there are signs of some modernization, i.e., spreading to non-aqueous titrations, expanding the
field of application to weak acids and bases as well as to potentiometric end point detection
improving the precision of the methods. With the development of functional group analysis
procedures, titrimetric methods have been shown to be beneficial in kinetic measurements which
are in turn applied to establish reaction rates. There are many advantages associated with these
methods which include saving time and labor, high precision and the fact that there is no need of
using reference standards. Titrimetric methods have been used for the determination of lisinopril
[11], albendozole [12] and gabapentin [13] in commercial dosage forms. Sparfloxacin was
determined by the non-aqueous titration method [14]. In addition to its application in drug
estimation, titrimetry has also been used for the estimation of degradation products of the
pharmaceuticals [15].
1.2 Chromatographic techniques
1.2.1 Thin layer chromatography
Although an old technique, yet it finds a lot of application in the field of pharmaceutical
analysis. In thin layer chromatography, a solid phase, the adsorbent, is coated onto a solid
support as a thin layer usually on a glass, plastic, or aluminum support. Several factors determine
the efficiency of this type of chromatographic separation. First the adsorbent should show
extreme selectivity toward the substances being separated so as to the dissimilarities in the rate
of elution be large. For the separation of any given mixture, some adsorbents may be of too
strongly adsorbing or too weakly adsorbing.Thin layer chromatography is a popular technique
for the analysis of a wide variety of organic and inorganic materials, because of its distinctive
advantages such as minimal sample clean-up, wide choice of mobile phases, flexibility in sample
distinction, high sample loading capacity and low cost. TLC is a powerful tool for screening
unknown materials in bulk drugs [16]. It provides a relatively high degree of assertion that all
probable components of the drug are separated. The high specificity of TLC has been exploited
to quantitative analytical purpose using spot elution followed by spectrophotometric
measurement. TLC has been utilized for the determination of some steroids [17], celecoxib [18]
and noscapine [19]. TLC plays a crucial role in the early stage of drug development when
information about the impurities and degradation products in drug substance and drug product is
inadequate. Various impurities of pharmaceuticals have been identified and determined using
TLC [20, 21].
1.2.2 High performance thin layer chromatography (HPTLC)
With the advancement of the technique, high performance thin layer chromatography
(HPTLC) emerged as an important instrumental technique in drug analysis. HPTLC is a fast
separation technique and flexible enough to analyze a wide variety of samples. This technique is
advantageous in many ways as it is simple to handle and requires a short analysis time to analyze
the complex or the crude sample. HPTLC evaluates the entire chromatogram with a variety of
parameters without time limits. Moreover, there is simultaneous but independent development of
multiple samples and standards on each plate, leading to an increased reliability of results.
HPTLC has been used to quantitate drugs, ethinyl estradiol and cyproterone [22], alfuzosin [23]
and tramadol and pentazocine [24].
1.2.3 High-performance liquid chromatography (HPLC)
HPLC is an advanced form of liquid chromatography used in separating the complex
mixture of molecules encountered in chemical and biological systems, in order to recognize
better the role of individual molecules. It was in the year 1980, HPLC methods appeared for the
first time for the assay of bulk drug materials [25]. This has become the principal method in USP
and Ph. Eur., The specificity of the HPLC method is excellent and simultaneously sufficient
precision is also attainable. However, it has to be stated that the astonishing specificity, precision
and accuracy are attainable only if wide-ranging system suitability tests are carried out before the
HPLC analysis. For this reason, the expense to be paid for high specificity, precision and
accuracy is also high.During the survey of the literature, it was observed that among the
chromatographic techniques, HPLC has been the most widely used method. In liquid
chromatography,the choice of detection is critical to guarantee that all the components are
detected. One of the widely used detectors in HPLC is UV detector which is capable of
monitoring several wavelengths concurrently.This is possible only by applying a multiple
wavelength scanning program. If present in adequate quantity, UV detector assures all the UV-
absorbing components are detected.
A photodiode array (PDA) is a lined array of discrete photodiodes on an integrated circuit
(IC) chip for spectroscopy. It is placed at the image plane of a spectrometer to allow a range of
wavelengths to be sensed concurrently. When a variable wavelength detector (VWD) is used, a
sample must be injected numerous times, with changing wavelength, to make sure that all the
peaks are detected. When PDA is used, a wavelength range can be programed and all the
compounds that absorb within this range can be identified in a single analysis. PDA detector can
also analyze peak purity by matching spectra within a peak. PDA detector finds its application in
the method development of Iloperidone in pharmaceuticals [26].The refractive index detector is
the detector of choice when one needs to detect analytes with restricted or no UV absorption
such as alcohols, sugars, carbohydrates, fatty acids, and polymers. Decent trace detection
performance is secured through a low noise. This detector is having the lowest sensitivity among
all detectors but suitable at high analyte concentrations. Lakshmi and Rajesh [27] utilized the
refractive index detector to analyze the content of volgibose in pharmaceutical formulations. The
electrochemical detector responds to the substances that are either oxidizable or reducible and
the electrical output results from an electron flow triggered by the chemical reaction that takes
place at the surface of the electrode. This detector was applied recently to analyze the content of
glutathione in human prostate cancer cells and lung adenocarcinoma cells [28].One of the most
sensitive detectors among the LC detectors is fluorescence detector. Typically its sensitivity is
10–1000 times higher than that of the UV detector.For strong UV absorbing materials, it is used
for the measurement of specific fluorescent species in samples. One of the most important
applications of fluorescence detector is in the estimation of pharmaceuticals [29].
Over a certain period of time most workers used the reversed-phase mode with UV
absorbance detection whenever appropriate, because this provided the best available reliability,
analysis time, repeatability and sensitivity. Several drugs have been assayed in pharmaceutical
formulations [30, 31] and in biological fluids (32) using HPLC. Thus, HPLC provides a major
service in answering many questions posted by the pharmaceutical industry. However, the
limitations of HPLC include price of columns, solvents and lack of long term reproducibility due
to the proprietary nature of column packing.
The analytical technique of liquid chromatography (LC) is used extensively thought the
pharmaceutical industry. It allows simultaneously both qualitative and quantitative information
of a drug. It is used to provide information on the composition of drug related samples. The
information obtained may be qualitative, indicating what compounds are present in the sample.
The information obtained may be qualitative, providing the actual amount of compounds in the
sample. LC is used in all the different stages in the creation of new drug discoveries and also
used routinely in the drug manufacturing process. High performance liquid chromatography
(HPLC) can be used in both qualitative and quantitative applications that are for both compound
identification and quantification. Normal phase HPLC is only rarely used now, almost all HPLC
separation can be performed in reverse phase. To understand the purpose of HPLC analytical
method it is necessary to consider the applications of HPLC in pharmaceutical analysis There are
wide verity of application throughout the processing of new drugs, from the initial drug
discovery to manufacture of formulated products which will administered to the patient [33-35].
In the majority of cases the use of reversed phase (RP) HPLC conditions and UV detection has
been reported.
Ultra performance liquid chromatography (UPLC) is a relatively new technique giving
new possibilities in liquid chromatography, especially concerning decrease of time and solvent
consumption. UPLC chromatographic system is designed in a special way to withstand high
system back-pressures. The UPLC system allows shortening analysis time up to nine times
comparing to the conventional system using 5 µm particle packed analytical columns. In
comparison with 3 µm particle packed analytical columns analysis should be shortened about
three times. The negative effect of particle decrease is back-pressure increase about nine times
(versus 5 µm) or three times (versus 3 µm), respectively. The separation on UPLC is performed
under very high pressures (up to 100 MPa is possible in UPLC system), but it has no negative
influence on analytical column or other components of chromatographic system. Separation
efficiency remains maintained or is even improved [36]. Tubing and connections in the system
are efficiently routed to maintain low dispersion and to take advantage of leak detectors that
interact with the software to alert the user to potential problems [37]. UPLC improves in three
areas: “speed, resolution, and sensitivity. In this system uses fine particles to support stationary
phase, so decrease the length of column, saves time and reduces solvent consumption [38]. The
advantages of UPLC in a pharmaceutical analysis were reviewed and reported [39 -41].
1.2.4 Gas chromatography
Moving ahead with another chromatographic technique, gas chromatography is a
powerful separation technique for detection of volatile organic compounds. Combining
separation and on-line detection allows accurate quantitative determination of complex mixtures,
including traces of compounds down to parts per trillions in some specific cases. Gas liquid
chromatography commands a substantial role in the analysis of pharmaceutical products. The
creation of high-molecular mass products such as polypeptides, or thermally unstable antibiotics
confines the scope of this technique. Its main constraint rests in the comparative non-volatility of
the drug substances.Therefore, derivatization is virtually compulsory. Recently, gas
chromatography has been used for assay of drugs such as isotretinion [42], and employed in the
determination of residual solvents in betamethasone valerate [43]. Gas chromatography is also an
important tool for analysis of impurities of pharmaceuticals. In recent years GC has been applied
to estimate the process related impurities of the pharmaceuticals [44].
1.3 Spectroscopic techniques
1.3.1 Spectrophotometry
Another important group of methods which find an important place in pharmacopoeias
are spectrophotometric methods based on natural UV absorption and chemical reactions.
Spectrophotometry is the quantitative measurement of the reflection or transmission properties of
a material as a function of wavelength.The advantages of these methods are low time and labor
consumption. The precision of these methods is also excellent. The use of UV–Visible
spectrophotometry especially applied in the analysis of pharmaceutical dosage forms has
increased rapidly over the last few years [45]. The colorimetric methods are usually based on the
following aspects: complex-formation reaction, oxidation-reduction process and catalytic
effect.It is important to mention that colorimetric methods are regularly used for the assay of
bulk materials. Derivative spectroscopy uses first or upper derivatives of absorbance with respect
to wavelength for qualitative investigation and estimation. The concept of derivatizing spectral
data was first offered in the 1950s, when it was shown to have many advantages. However, the
technique received little consideration primarily due to the complexity of generating derivative
spectra using early UV–Visible spectrophotometers. The introduction of microcomputers in the
late 1970s made it generally convincing to use mathematical methods to generate derivative
spectra quickly, easily and reproducibly. This significantly increased the use of the derivative
technique. The derivative method has found its applications not only in UV-Visible
spectrophotometry but also in infrared, atomic absorption, fluorescence spectrometry, and in
fluorimetry. The use of derivative spectrometry is not restricted to special cases, but may be of
advantage whenever quantitative study of normal spectra is problematic. Disadvantage is also
associated with derivative methods; the differential degrades the signal-to-noise ratio, so that
some form of smoothing is required in conjunction with differentiation.
1.3.2 Near infrared spectroscopy (NIRS)
Near infrared spectroscopy (NIRS) is a rapid and non-destructive procedure that provides
multi component analysis of almost any matrix. In recent years, NIR spectroscopy has gained a
wide appreciation within the pharmaceutical industry for raw material testing, product quality
control and process monitoring. The growing pharmaceutical interest in NIR spectroscopy is
probably a direct consequence of its major advantages over other analytical techniques, namely,
an easy sample preparation without any pretreatments, the probability of separating the sample
measurement by use of fiber optic probes, and the expectation of chemical and physical sample
parameters from one single spectrum. The major pharmacopoeias have generally adopted NIR
techniques. The European Pharmacopoeia [46], United States pharmacopoeia [47] and British
Pharmacopoeia [48] address the suitability of NIR instrumentation for application in
pharmaceutical testing. NIR spectroscopy in combination with multivariant data analysis opens
many interesting perceptions in pharmaceutical analysis, both qualitatively and quantitatively. A
number of publications describing quantitative NIR measurements of active ingredient in intact
tablets have been reported [49, 50].
1.3.3 Nuclear magnetic resonance spectroscopy (NMR)
Since the first report appeared in 1996 describing the use of NMR spectroscopy to screen
for the drug molecules [51], the field of NMR based screening has proceeded promptly. Over the
last few years, a variety of state-of-the-art approaches have been presented and found widespread
application in both pharmaceutical and academic research. Recently NMR finds its application in
quantitative analysis in order to determine the impurity of the drug, characterization of the
composition of the drug products and in quantitation of drugs in pharmaceutical
formulations[52].
1.3.4 Fluorimetry and phosphorimetry
Pharmaceutical industries continuously look for the sensitive analytical techniques using
the micro samples. Fluorescence spectrometry is one of the techniques that serve the purpose of
high sensitivity without the loss of specificity or precision. A gradual increase in the number of
articles on the application of fluorimetry [53] and phosphorimetry [54] in quantitative analysis of
various drugs in dosage forms and biological fluids has been noticed in the recent past.
1.4 Electrochemical methods
Electrochemistry is originated from the study of the movement of electrons in an
oxidation–reduction reaction. The basis of the techniqueis a measurement of potential, charge, or
current to determine an analyte concentration or to characterize an analyte’s chemical
reactivity.To understand electrochemistry, we need to appreciate five important and interrelated
concepts [55]:
• The electrode’s potential determines the analyte’s form at the electrode surface;
• The concentration of analyte at the electrode surface may not be the same as its
concentration in bulk solution;
• In addition to an oxidation–reduction reaction, the analyte may participate in other
reactions;
• Current is a measure of the rate of the analyte’s oxidation or reduction; and
• We cannot simultaneously control current and potential.
Electrochemical techniques mostly are being used in potentiometric methods,
coulometric methods, voltammetric methods and amperometric methods. The application of
electrochemical techniques in the analysis of drugs and pharmaceuticals has increased greatly
over the last few years. The renewed interest in electrochemical techniques can be attributed in
part to more sophisticated instrumentation and to increase the understanding of the techniques
themselves.A large number of electroanalytical methods are available for quantification of
pharmaceuticals.
1.5 Kinetic method of analysis
Kinetic method of analysis has been developing since 1950s and yet in modern days it is
taking a major resurgence in activity. The repetitive interest in the kinetic methods can be
credited to the advancements made in principles, in automated instrumentation, in data analysis
methods and in the analytical applications.
From the literature it is evident that the kinetic approach to analytical chemistry is rather
general with several advantages over traditional equilibrium approach. Essentially, kinetic
methods trust the measurements of concentration changes (detected via signal changes) in a
reactant (which may be the analyte itself) with time after the sample and reagents have been
mixed manually or mechanically.Going through the literature, it can be noticed that fixed-time
and initial rate methods have been used more often for the determination of drugs in
pharmaceutical formulations [56]. Automatic techniques for the kinetic methods are generally
based on open systems; among the popular techniques are the stopped flow systems[57].
1.6 Electrophoretic methods
Another important instrument available for the analysis of pharmaceuticals is capillary
electrophoresis (CE). In this technique, solutes are perceived as peaks as they pass through the
detector and the areas of individual peaks are proportional to their concentration, which allows
quantitative estimations. In addition to pharmaceutical studies it finds an application in the
analysis of biopolymers and inorganic ions. CE analysis, generally more effective, can be
performed on a quicker time scale and requires only a small amount(innano liter injection
volumes) and in most cases, takes place under aqueous conditions. These four characteristics of
CE have proven to be beneficial to many pharmaceutical applications. Several reports have
appeared on the application of this technique in the routine drug analysis. CE is a relatively new
analytical technique based on the separation of charged analytes through a small capillary under
the impact of an electric field [58]. Bupinder singh [59] reported an overview on the use of
capillary electrophoresis methods in
pharmaceutical,biopharmaceuticalandbiotechnologyapplications.
1.7 Flow injection and sequential injection analysis
Laboratory automation was introduced in the second half of the 20th
century. Stewart in
the U.S. as well as Ruzicka and Hansen in Denmark, developed the flow injection analysis (FIA)
technique for the automation of chemical procedures [60, 61]. A sample (analyste) is injected
into a carrier solution which mixes through radial and convection diffusion with a reagent for a
period of time (depends on the flow rate and the coil length and diameter) before the sample
passes through a detector to waste. The introduction of this technique approached to transform
the conception of automation in chemical analysis by permitting instrumental measurement to be
carried out in the absence of physical and chemical equilibrium. The principle of flow injection
analysis (FIA) is injection of a liquid sample into a moving, non-segmented uninterrupted carrier
stream of a suitable liquid. The injected sample forms a zone, which is then transported towards
a detector that uninterruptedly records the changes in absorbance, electrode potential, or other
physical parameter resulting from the passage of the sample material through the flow cell.
Stages of flow injection analysis shown in Figure 1.
Figure 1: Stages of flow injection analysis
Following the broad application of computers in routine laboratoryanalysis a second
generation of flow analysis was offered byRuzicka and Marshall [62], who titled it as sequential
injection analysis (SIA). Like FIA, this is a non-segmented continuous flow arrangement based
on the similar principle of controlled dispersion and reproducible manipulation of the FIA
perception, but whose mode of operation is based on the theory of programmable flow.The FIA
technique has lent a significant contribution to the advancement of automation in pharmaceutical
analysis. By profiting from the advantages in the economy of reagents and the elevated sampling
rates, the majority of the applications are dedicated to the determination of active ingredients for
quality control in pharmaceutical formulations.
1.8 Hyphenated techniques
The coupling of a separation technique and an on-line separation technique leads to the
development of hyphenated technique. A hyphenated technique in analytical chemistry is ‘the
marriage of two separate analytical techniques via appropriate interfaces, usually with backup of a
computer tying everything together’. “Hyphenation” term was first coined by Hirschfield although
the idea itself began with coupling of GC & MS in the early 1970`s [63].In recent years, hyphenated
techniques have received ever-increasing attention as the principal means to solve complex
analytical problems. The power of combining separation technologies with spectroscopic
techniques has been demonstrated over the years for both quantitative and qualitative analysis of
unknown compounds in complex natural product extracts or fractions. To obtain structural
information leading to the identification of the compounds present in a crude sample, liquid
chromatography (LC), usually a high-performance liquid chromatography (HPLC), gas
chromatography (GC), or capillary electrophoresis (CE) is linked to spectroscopic detection.
Fourier-transform infrared (FTIR), photodiode array (PDA) UV-vis absorbance or fluorescence
emission, mass spectroscopy (MS), and nuclear magnetic resonance spectroscopy (NMR), are
sum of the modern hyphenated techniques. A variety of hyphenated techniques such as LC-MS
[64], GC-MS [65], LC-NMR [66], ICP-MS [67], CE-MS [68] have been applied in the analysis
of pharmaceuticals. The determination of drugs in biological materials is an important step in
drug discovery and drug development.
Section – (ii): Introduction to drugs
A pharmaceutical drug also referred to as a medicine or (loosely) medication, officially
called medicinal product, can be defined as any chemical substance or product intended for use
in the medical diagnosis, cure treatment or prevention of disease. The word pharmaceutical
comes from the Greek word “Pharmakeia”. The modern transliteration of pharmakeia is
pharmacia.Medicines can be classified in various ways, such as by chemical properties, mode of
route of administration, biological system affected or therapeutic effects. An elaborate and
widely used classification system is the anatomical therapeutic chemical classification system
(ATC system).Based on the health problems related to different organs in human body, the drugs
are classified and used in the treatment.
S.No Category Description
1 Gastrointestina
l tract
antacids, reflux suppressants, antiflatulent,antidopaminergics, proton
pump inhibitors (PPIs), H2-receptor
antagonists, cytoprotectants, prostaglandin analogues,
laxatives, antispasmodics, antidiarrhoeals, bile acid sequestrants, opioid
2 Cardiovascular
system
β-receptor blockers ("beta blockers"), calcium channel
blockers, diuretics, cardiac glycosides, antiarrhythmics, nitrate,
antianginals, vasoconstrictors, vasodilators, peripheral activators
3 Central nervous
system Psychedelics,hypnotics, anaesthetics, antipsychotics, antidepressants,
antiemetics,anticonvulsants/antiepileptics, anxiolytics, barbiturates
4
Pain and
consciousness
(analgesic)
The main classes of painkillers are NSAIDs, opioids and
variousorphanssuch as paracetamol. Other drugs such as anesthetic
medication can also be used to reduce pain or numb a person's feeling to
it.
5
Musculo-
skeletal
disorders
The main categories of drugs for musculoskeletal disorders are:
NSAIDs(including COX-2 selective inhibitors), muscle relaxants,
neuromusculardrugs, and anticholinesterases.
6 Eye
• Antibacterial: antibiotics, topical antibiotics, sulfa
drugs,aminoglycosides, fluoroquinolones
• Antiviral drug, Anti-fungal: imidazoles, polyenes
• Anti-inflammatory: NSAIDs, corticosteroids
• Anti-allergy: mast cell inhibitors
• Anti-glaucoma: adrenergic agonists, beta-blockers, carbonic
anhydrase
inhibitors/hyperosmotics, cholinergics, miotics, parasympathomimet
ics,
7 Ear, Nose and
Oropharynx Sympathomimetics, antihistamines, anticholinergics, NSAIDs, steroids,a
ntiseptics, local anesthetics, antifungals, cerumenolyti
8 Respiratory
system
Bronchodilators, NSAIDs, anti-allergics, antitussives,
mucolytics,decongestants, corticosteroids, Beta2-adrenergic agonists,
anticholinergics, steroids
9 Endocrine probl
ems
Androgens, antiandrogens, gonadotropin, corticosteroids, human growth
hormone, insulin, antidiabetics, thyroid hormones, antithyroid
drugs, calcitonin,diphosponate, vasopressin analogues
10
Reproductive
system or urinar
y system
Antifungal, alkalinizingagents, quinolones, antibiotics, cholinergics,anti
cholinergics, anticholinesterases, antispasmodics, 5-alpha reductase
inhibitor, selective alpha-1 blockers, sildenafils, fertility medications
11 Contraception Hormonal contraception, Ormeloxifene, Spermicide
12 Obstetrics and g
ynecology
NSAIDs, anticholinergics, haemostatic
drugs, antifibrinolytics, Hormone Replacement Therapy (HRT), bone
regulators, beta-receptor agonists,follicle stimulating
hormone, luteinising hormone, LHRH
gamolenic acid, gonadotropin release inhibitor,
13 Skin
Emollients, anti-
pruritics, antifungals, disinfectants, scabicides,pediculicides, tar product
s, vitamin A derivatives, vitamin D
analogues,keratolytics, abrasives, systemic
antibiotics, topical antibiotics, hormones,desloughing agents, exudate
absorbents,
14 Infections and i
nfestations
Antibiotics, antifungals, antileprotics, antituberculous
drugs, antimalarials,anthelmintics, amoebicides, antivirals, antiprotozoal
s
15 Immune system Vaccines, immunoglobulins, immune
suppressants, interferons, monoclonal antibodies
16 Allergic
disorders Anti-allergics, antihistamines, NSAIDs
17 Nutrition Tonics, electrolytes and mineral preparations, Parental nutritional
supplements, vitamins, anti-obesity drugs, anabolic
drugs, haematopoietic drugs, food product drugs
18 Neoplastic
disorders cytotoxic drugs, therapeutic antibodies, sex hormones, erythropoietin
inhibitors, somatostatin inhibitors, recombinant interleukins, aromatase
19 Diagnostics Contrast media
20 Euthanasia Euthanaticum is used for euthanasia and physician-assisted suicide.
Euthanasia is not permitted by law in many countries, and consequently
medicines will not be licensed for this use in those countries.
2.0 Proton pump inhibitors (PPIs)
Proton-pump inhibitors (PPIs) are a group of drugs whose main action is a pronounced
and long-lasting in the reduction of gastric acid production. They are the most potent inhibitors
of acid secretion available. Proton pump inhibitors reduce the production of acid by blocking the
enzyme in the wall of the stomach that produces acid. The reduction of acidprevents ulcers and
allows any ulcers that exist in the esophagus, stomach, and duodenum to heal.These drugs are
among the most widely sold drugs in the world, and are generally considered effective[69]. The
vast majority of these drugs arebenzimidazole derivatives, but promising new research indicates
the imidazopyridinederivatives may be a more effective means of treatment[70]. High dose or
long-term use of PPIs carries a possible increased risk of bone fractures[71]. The PPIs such as
omeprazole (Prilosec), lansoparazole (Prevacid), pantoprazole (Protonix), and several brand
name drugs are more effective for most people compared to H2 blockers such as ranitadine
(Zantac) and famotadine (Pepcid). The group followed and has largely superseded another group
of pharmaceuticals with similar effects, but a different mode of action, called H2-receptor
antagonists.The advantage of omeprazole over H2 receptor antagonists, in terms of endoscopic
healing and symptom relief, is at least as great in elderly patients as in younger patients [72].
Figure 2: Gastroesophageal reflux disease Figure 3: Zollinger-Ellison syndrome
Proton pump inhibitors are used for the prevention and treatment of acid-related
conditions such as:ulcers,gastroesophageal reflux disease (Figure 2), andZollinger-Ellison
syndrome(Figure 3).They also are used in combination with antibiotics for eradicating
helicobacter pylori, a bacterium that together with acid causes ulcers of
thestomach and duodenum.Examples of proton pump inhibitors approved in the United States
include: omeprazole (Prilosec), lansoprazole (Prevacid), rabeprazole (Aciphex), pantoprazole
(Protonix), esomeprazole (Nexium), and Zegarid.
There are many different names and brands of PPIs. Most of them work as well as
another. Side effects may be different for different ones.
• Omeprazole (Prilosec), also available over the counter without a prescription
• Esomeprazole (Nexium),
• Lansoprazole (Prevacid),
• Rabeprazole (AcipHex),
• Pantoprazole (Protonix),
• Dexlansoprazole (Kapidex)
2.1Anti-inflammatory drugs
Anti-inflammatory refers to the property of a substance or treatment that
reduces inflammation. Anti-inflammatory drugs make up about half of analgesics, remedying
pain by reducing inflammation as opposed to opioids, which affect the central nervous
system.Prostaglandins are a family of chemicals that are produced by the cells of the body and
have several important functions. They support the blood clotting function of platelets; and
protect the lining of the stomach from the damaging effects of acid.Prostaglandins are produced
within the body's cells by the enzyme cyclooxygenase (COX). There are two COX enzymes,
COX-1 and COX-2. Both enzymes produce prostaglandins that promote inflammation, pain, and
fever. However, only COX-1 produces prostaglandins that support platelets and protect the
stomach. Nonsteroidal antiinflammatory drugs (NSAIDs) block the COX enzymes and reduce
prostaglandins throughout the body. As a consequence, ongoing inflammation, pain, and fever
are reduced. Since the prostaglandins that protect the stomach and support platelets and blood
clotting also are reduced, NSAIDs can cause ulcers in the stomach and promote
bleeding.NSAIDs are used primarily to treat inflammation, mild to moderate pain, and fever.
Specific uses include the treatment of headaches, arthritis, sports injuries, and menstrual cramps.
Ketorolac (Toradol) is only used for short-term treatment of moderately severe acute pain that
otherwise would be treated with opioids. Aspirin (also a NSAID) is used to inhibit the clotting of
blood and prevent strokes and heart attacks in individuals at high risk. NSAIDs also are included
in many cold and allergy preparations.
Crohn’s disease (CD) and ulcerative colitis (UC) are the two major forms of idiopathic
inflammatory bowel disease (IBD). The pathogenesis of this disease is incompletely understood
and there are no medical cures available at this time. Several pharmacological therapies aimed at
controlling intestinal inflammation have been developed. Corticosteroids and amino- salicylates
have been at the cornerstone of IBD therapy for decades and, in general, act via multiple
nonspecific systemic and local immunosuppressant effects, respectively. Biological therapies
such as engineered antibodies against tumor necrosis factor-α have more potent and precise anti-
inflammatory actions.Aminosalicylates are one of the oldest therapies currently used in the
management of IBD. Salazopyrin is the prototype drug in this category, but mesalazine (5-
aminosalicylic acid [5-ASA]) is the active moiety of this parent compound and is the main
aminosalicylate used in IBD treatment today. These are very safe drugs that can be administered
orally or rectally to manage inflammation localized to different regions of the gastrointestinal
tract, with little systemic absorption. Administration of 5-ASA in multiple daily doses is largely
an extrapolation of how the parent compound, sulfasalazine, was given to avoid toxicities
associated with the sulfapyridine moiety which is readily absorbed after oral dosing[73].
Figure 4:Crohn`s disease Figure 5:Ulcerative colitis
Incrohn’s disease (Figure 4), inflammation may occur anywhere along the digestive tract,
itmay occur in patches and colon wall may be thickened and may have a rocky appearance.
Ulcers along the digestive track are deep and may extend into all layers of the bowel wall in
chohn`s disease. In ulcerative colitis (Figure 5), large intestine (colon) is typically the only
affected site, inflammation is continuous throughout affected areas and colon wall is thinner and
shows continuous inflammation. Mucus lining of large intestine may have ulcers, but they do not
extend beyond the inner lining in ulcerative colitis.
Mesalamine is a drug used for treatingulcerative colitis. The exact mechanism of
mesalamine is not known but is believed to be by reducing inflammation in the colon. Ulcerative
colitis and other inflammatory diseases cause excessive production of chemicals, for example,
prostaglandins, that produce inflammation in the colon. Prostaglandins are produced by the
enzymes, cyclooxygenase and lipoxygenase. These enzymes are over-active in individuals with
ulcerative colitis. Mesalamine may work by blocking the activity of cyclooxygenase and
lipoxygenase, thereby, reducing the production of prostaglandins. Reduced production of
prostaglandins decreases inflammation in the colon and the symptoms associated with ulcerative
colitis. Available forms of mesalamine differ in their route of administration and how often they
are administered. Mesalamine is used for the treatment of mild to moderately severe ulcerative
colitis. The suppositories are limited to use in ulcerative colitis involving only the rectum
(proctitis) and the enemas tocolitis involving only the part of the colon close to the rectum (distal
colitis) or proctitis. While the benefits of mesalamine can be seen within 3 to 21 days of starting
therapy, it may take up to three to six weeks for the enemas and suppositories, six weeks for the
tablets, and eight weeks for the capsules to have maximum effect.Recent advances in
pharmaceutical formulation and clinical application of 5-ASA, as well as improved knowledge
of its mechanisms of action and colon cancer chemoprophylactic effects, has led to renewed
interest in this foundational drug in IBD therapy [74].
2.2 Anti diabetic drugs:
Drugs used in diabetes treat diabetes mellitus by lowering glucose levels in the blood.
With the exceptions of insulin, exenatide, liraglutide and pramlintide, all are administered orally
and are thus also called oral hypoglycemic agents or oral antihyperglycemic agents. There are
different classes of anti-diabetic drugs, and their selection depends on the nature of the diabetes,
age and situation of the person, as well as other factors.Diabetes mellitus type 1 is a disease
caused by the lack of insulin. Insulin must be used in Type I, which must be injected.Diabetes
mellitus type 2 is a disease of insulin resistance by cells. Treatments include (1) agents that
increase the amount of insulin secreted by the pancreas, (2) agents that increase the sensitivity of
target organs to insulin, and (3) agents that decrease the rate at which glucose is absorbed from
the gastrointestinal tract. The steps involved in diabetes is shown in Figure 6.
Figure 6: Steps involved in diabetes
2.3 Biguanides:
Insulin sensitizers address the core problem in Type II diabetes, insulin
resistance.biguanides reduce hepatic glucose output and increase uptake of glucose by the
periphery, including skeletal muscle. Although it must be used with caution in patients with
impaired liver orkidney function, metformin has become the most commonly used agent for type
2 diabetes in children and teenagers. Among common diabetic drugs, metformin is the only
widely used oral drug that does not cause weight gain.Typical reduction in glycated
hemoglobin (A1C) values for metformin is 1.5–2.0%. Metformin is usually the first-line
medication used for treatment of type 2 diabetes. In general, it is prescribed at initial diagnosis in
conjunction with exercise and weight loss, as opposed to in the past, where it was prescribed
after diet and exercise had failed. There is an immediate release as well as an extended-release
formulation, typically reserved for patients experiencing GI side-effects. It is also available in
combination with other oral diabetic medications.Biguanide can refer to a molecule, or to a class
of drugs based upon this molecule. Biguanides can function as oral
antihyperglycemic drugs used for diabetes mellitus or prediabetes treatment. They are also used
as antimalarial drugs.Biguanides do not affect the output of insulin, unlike other hypoglycemic
agents such as sulfonylureas and meglitinides. Therefore, not only are they effective in Type 2
diabetics but they can also be effective in Type 1 patients in concert with insulin therapy.
The mechanism of action of biguanides is not fully understood. Mainly used in Type II
diabetes, metformin is considered to increase insulin sensitivity in vivo, resulting in reduced
plasma glucose concentrations, increased glucose uptake, and decreased
gluconeogenesis.However, in hyperinsulinemia, biguanides can lower fasting levels of insulin in
plasma. Their therapeutic uses derive from their tendency to reducegluconeogenesis in the liver,
and, as a result, reduce the level of glucose in the blood. Biguanides also tend to make the cells
of the body more willing to absorb glucose already present in the blood stream, and thereby
reducing the level of glucose in the plasma.
Examples of biguanides:
• Metformin - widely used in treatment of diabetes mellitus type 2
• Phenformin - withdrawn from the market in most countries due to toxic effects
• Buformin - withdrawn from the market due to toxic effects
• Proguanil - an antimalarial drug.
2.4 Dipeptidyl peptidase-4 inhibitors
Inhibitors of dipeptidyl peptidase 4, also DPP-4 inhibitors or gliptins, are a class of oral
hypoglycemics that block DPP-4. They can be used to treat diabetes mellitus type
2.Glucagon increases blood glucose levels, and DPP-4 inhibitors reduce glucagon and blood
glucose levels. The mechanism of DPP-4 inhibitors is to increase incretin levels (GLP-
1 and GIP) [75, 76] which inhibit glucagon release, which in turn increases insulin secretion,
decreases gastric emptying, and decreases blood glucose levels.
Secretagogues are the drugs that increase insulin output from pancreas. DPP-4 inhibitors
are weight-neutral and increase risk for infection and headache, but both classes appear to
present an alternative to other antidiabetic drugs. Dipeptidyl peptidase-4 (DPP-4) inhibitors
increase blood concentration of the incretin glucagon like peptide-1 (GLP-1) by inhibiting its
degradation by dipeptidyl peptidase-4. DPP-4 inhibitors lowered hemoglobin A1C values by
0.74%, comparable to other antidiabetic drugs[77].A combined result of 5 RCTs enlisting a total
of 238 patients aged 65 or older (mean baseline HbA1c of 8.6%) receiving 100 mg/d
of vildagliptin was shown to reduce HbA1c by 1.2% [78].
• Vildagliptin (Galvus)
• Sitagliptin (Januvia)
• Saxagliptin (Onglyza)
• Linagliptin (Tradjenta)
• Allogliptin
• Septagliptin
The combination with DPP-4 inhibition, metformin has been shown to be highly tolerable
with very low risk of hypoglycemia.DPP-4 inhibition in combination with metformin is an
efficient, safland tolerable combination therapy for type 2 diabetes [79].
Classification of anti-diabetic drugs and insulin analogs
Insulin
Sensitizers
Biguanides Metformin, Buformin, Phenformin
TZDs /
“glitazones”
(PPAR)
Pioglitazone, Rosiglitazone,
Rivoglitazone
Dual PPAR
agonists Aliglitazar, Muraglitazar, Saroglirazar
Secretagogues
K+ ATP
Sulfonyreas Tolbutamide,
Glimepiride
Meglitinides /
“glinides”
Nateglinide,
Repaglinide
GLP-1 agonists Exenatide, Liraglutide
DPP4 inhibitors Vildagliptin, Allogliptin
Analogs / other insulins Insulin lispro, regular insulin, glargine, degludec, exubera.
Others Alpha glucose inhibitors Acarbose, Miglitol, Voglibose
Amylin analog Pramlintide
SGLT2 inhibitors Canagliflozin, Remogliflozin
Others Benfluores, Tolrestat
2.5 Antihypertensive drugs
Antihypertensives are a class of drugs that are used to treat hypertension (high blood
pressure)[80] Antihypertensive therapy seeks to prevent the complications of high blood
pressure, such asstroke and myocardial infarction. Evidence suggests that reduction of the blood
pressure by 5 mmHg can decrease the risk of stroke by 34%, ischaemic heart disease by 21%,
and reduce the likelihood of dementia, heart failure, and mortality
from cardiovasculardisease[81]. There are many classes of antihypertensives, which lower blood
pressure by different means; among the most important and most widely used are
the thiazide diuretics, the ACE inhibitors, the calcium channel blockers, the beta blockers, and
the angiotensin II receptor antagonists or angiotensin receptor blockers(ARBs).The comparison
between normal heart and hypertensive heart was shown in Figure 7.
Figure 7: The comparison between normal and hypertensive heart
2.6 Angiotensin II receptor antagonists
Angiotensin II receptor antagonists, also known as angiotensin receptor blockers, AT1-
receptor antagonists or sartans, are a group of pharmaceuticals that modulate the renin-
angiotensin-aldosterone system. Their main uses are in the treatment of hypertension(high blood
pressure),diabetic nephropathy (kidney damage due to diabetes) and congestive heart failure.
Angiotensin, formed in the blood by the action of angiotensin converting enzyme (ACE), is a
powerful chemical that attaches to angiotensin receptors found in many tissues but primarily on
muscle cells of blood vessels. Angiotensin's attachment to the receptors causes muscle cells to
shorten and narrow the blood vessels (vasoconstrict), which leads to an increase in blood
pressure (hypertension). Telmisartan blocks the angiotensin receptor. By blocking the action of
angiotensin, telmisartan widens blood vessels (vasodilate) and reduces blood pressure.
Telmisartan was approved by the FDA in November 2000. Other similar type of drugs are
• Candesartan
• Eprosartan
• Irbesartan
• Losartan
• Olmesartan
• Telmisartan
• Valsartan
2.7 Antibiotics
Antibiotics, also known as antibacterials, are types of medications that destroy or slow
down the growth of bacteria. In Greek, the word anti means against, and biosmeans life. The
term antibiotic was first used in 1942 by Selman Waksman and his collaborators in journal
articles to describe any substance produced by a microorganism that is antagonistic to the growth
of other microorganisms in high dilution [82]. Antibiotics are used to treat infections caused by
bacteria. Bacteria are microscopic organisms, some of which may cause illness.Illnesses such
as syphilis, tuberculosis, salmonella, and some forms of meningitisare are caused by bacteria.
Some bacteria are harmless, while others are good for us. Before bacteria can multiply and cause
symptoms, the body's immune system can usually destroy them. We have special white blood
cells that attack harmful bacteria. Even if symptoms do occur, our immune system can usually
cope and fight off the infection. There are occasions, however, when it is all too much and some
help is neededfrom antibiotics.
The first antibiotic was penicillin. Such penicillin-related antibiotics as ampicillin,
amoxicillin and benzylpenicilllin are widely used today to treat a variety of infections. These
antibiotics have been around for a long time. There are several different types of modern
antibiotics and they are only available with a doctor's prescription in industrialized
countries.An antibacterial is an agent that inhibits bacterial growth or kills bacteria. The term is
often used synonymously with the term antibiotic(s). Today, however, with increased knowledge
of the causative agents of various infectious diseases, antibiotic(s) has come to denote a broader
range of antimicrobial compounds, including anti-fungal and other compounds.
There is concern worldwide that antibiotics are being overused. Antibiotic overuse is one
of the factors that contributes towards the growing number of bacterial infections which are
becoming resistant to antibacterial medications. According to the CDC (Centers for Disease
Control and Prevention), outpatient antibiotic overuse in the USA is a particular problem in the
Southeast. According to the ECDC (European Centre for Disease Prevention and Control),
antibiotic resistance continues to be a serious public health threat worldwide. In a statement
issued on 19th November 2012, the ECDC informed that an estimated 25,000 people die each
year in the European Union from antibiotic-resistant bacterial infections.
Although there are a number of different types of antibiotics they all work in one of two
ways: 1. A bactericidal antibiotic kills the bacteria. Penicillin is a bactericidal. A bactericidal
usually either interferes with the formation of the bacterium's cell wall or its cell contents,2.A
bacteriostatic stops bacteria from multiplying.An antibiotic is given for the treatment of an
infection caused by bacteria. Antibiotics target microorganisms such as bacteria, fungi and
parasites. However, they are not effective against viruses. If you have an infection it is important
to know whether it is caused by bacteria or a virus. Most upper respiratory tract infections, such
as the common cold and sore throats are generally caused by viruses.Antibiotics do not work
against these viruses.
Ciprofloxacin is one of the fluorinated quinolones structurally related to nalidixic acid. It
is a broad spectrum antibiotic, more sensitive to gram- negative bacteria, and less effective
against grampositive bacteria, including staphylococcus aureus, streptococcuspneumoniae, and
enterococcus faecalis [83, 84].Initially, ciprofloxacinwas used to treat infections caused by gram
negative and gram positive organisms very successfully and resistance was very rare. However,
its introduction in the treatment of a broad range of clinical conditions such as the treatment of
urinary tract infections, upper respiratory tract infections, and as a prophylaxis for neutropenic
patients, as well as its use in veterinary medicine, resistant strains began to emerge
[85].Ciprofloxacin is a valuable antibiotic for the empiric treatment of urinary tract
infections,nevertheless quinolone’s resistance should be monitored adequately [86].
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