Chapter-1

Introduction to

analytical

techniques and

drugs

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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