Thesis

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OCULAR DRUG DELIVERY:-

INTRODUCTION:-

Ocular administration of the drug is primarily related with the treatment of ophthalmic

diseases, not for gaining systemic

action. Ophthalmic drug delivery is one of the most

interesting and challenging endeavors facing the pharmaceutical scientist. The anatomy,

physiology, and biochemistry of the eye render this organ highly impervious to foreign

substances. A significant challenge to the formulator is to circumvent the protective barriers of

the eye without causing permanent tissue damage. Development of newer, more sensitive

diagnostic techniques and novel therapeutic agents continue to provide ocular delivery systems

with high therapeutic efficacy. The goal of pharmacotherapeutics is to treat a disease in a

consistent and predictable fashion. An assumption is made that a correlation exists between the

concentrations of a drug at its intended site of action and the resulting pharmacological effect.

The specific aim of designing a therapeutic system is to achieve an optimal concentration of a

drug at the active site for the appropriate duration. Ocular disposition and elimination of a

therapeutic agent is dependent upon its physicochemical properties as well as the relevant ocular

anatomy and physiology. A successful design of a drug delivery system, therefore, requires an

integrated knowledge of the drug molecule and the constraints offered by the ocular route

of administration. Major classes of the drugs that are administered through ocular route are

SHRI RAWATPURA INSTITUTE OF PHARMACY, KUMHARI

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Miotics, Mydriatics/Cycloplegics, Anti-inflammatories, Anti-infectives, Surgical adjuvants,

Diagnostics etc. Historically, the bulk of the research has been aimed at delivery to the anterior

segment tissues, but whenever an ophthalmic drug is applied topically to the anterior segment of

the eye, only a small amount (5%) actually penetrates the cornea and

reaches the internal

anterior tissue of the eyes. Rapid and efficient drainage by the nasolacrimal apparatus,

noncorneal absorption, and the relative impermeability of the cornea to both hydrophilic and

hydrophobic molecules, all account for such poor ocular bioavailability. The various approaches

that have been attempted to increase the bioavailability and the duration of the therapeutic action

of ocular drugs can be divided into two categories. The first one is based on the use of sustained

drug delivery systems, which provide the controlled and continuous delivery of ophthalmic

drugs, such as implants, inserts, and colloids. The second involves maximizing corneal drug

absorption and minimizing precorneal drug loss through viscosity and penetration enhancers,

prodrugs, and colloids. Drug delivery to the posterior eye, where 40% of main ocular diseases

are located, is another great challenge in ophthalmology. Only recently has research been

directed at delivery to the tissues of the posterior globe.

Development of new drug candidates and novel delivery techniques for treatment of ocular

diseases has recently accelerated. Treatment of anterior-segment diseases has witnessed

advances in prodrug formulations and permeability enhancers. Intravitreal, subconjunctival, and

periocular routes of administration and sustained-release formulations of nanoparticles and

microparticles, as well as nonbiodegradable and biodegradable implants to deliver drugs to the

posterior segment of the eye, are becoming popular therapeutic approaches. Without adequate

regulatory guidance for ocular drugs, such routes of administration and novel formulations can

pose unique challenges to those involved in designing nonclinical programs, including

considering clinical and nonclinical factors and choosing species, strains, and ocular toxicity

parameters. Toxicology pathologists also contribute practical experience to evaluating

morphological effects of these novel formulations. Lastly, understanding species’ anatomical

differences is useful for interpreting toxicological and pathological responses to the eye and is


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important for human risk assessment of these important new therapies for ocular diseases.

Certain ocular diseases are quite rare, whereas others, such as cataracts, age-related macular

degeneration (AMD), and glaucoma, are very common, especially in the aging population. A

rapid expansion of new technologies in ocular drug delivery and new drug candidates, including

biologics, to treat these challenging diseases in the anterior and posterior segments of the eye

have recently emerged. These approaches are necessary because the eye has many unique

barriers to drug delivery. Current routes of administration include but are not limited to topical

administration, systemic administration, intravitreal injections, and intraocular implants, each of

which has its own set of complications and disadvantages. Ocular bioavailability after topical

ocular eye drop administration, the most common form of ocular medication, is less than 5% and

often less than 1%, and therefore, only the diseases of the anterior segment of the eye can be

treated with eye drops. Blood-ocular barriers, including tight junction complexes between ciliary

and retinal pigmented epithelium, non fenestrate and iridal capillaries, and P-glycoprotein efflux

pumps, are defense mechanisms to protect the eye from circulating antigens, inflammatory

mediators, and pathogens. Unfortunately, they also act as a considerable barrier to systemically

administered drugs. Ocular delivery from intravitreal, subconjunctival, and periocular sites to the

posterior segment is becoming a popular approach to support the development of new injectable

and implantable prolonged-action dosage forms. Regulatory expectations for nonclinical testing

of ocular drugs are not well defined, and regional differences exist. Many toxicologists and

pathologists new to this field are responsible for developing novel ocular drugs or novel delivery

techniques using an existing ocular or systemic drug. The objective of this review is to briefly

summarize some of the newer methods of administering ocular drugs; to provide a spectrum of

toxicological and pathological viewpoints for nonclinical development, including regulatory

considerations, species selection, study design, morphological evaluation, and relationship of

pathology data to functional endpoints; and to ensure a comprehensive and meaningful risk

assessment for humans. A major problem in ocular therapeutics is the attainment of an optimal

drug concentration at the site of action. Poor bioavailability of drugs from ocular dosage forms is

mainly due to the precorneal loss factors which include tear dynamics, non-productive

absorption, transient residence time in the cul-de-sac, and the relative impermeability of the

corneal epithelial membrane. Due to these physiological and anatomical constraints only a small

fraction of the drug, effectively 1% or even less of the instilled dose is ocularly absorbed. The


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effective dose of medication administered ophthalmically may be altered by varying the strength,

volume, or frequency of administration of the medication or the retention time of medication in

contact with the surface of the eye. This review is an attempt to focus on the recent findings,

development in the ocular drug delivery system. Various approaches being used to improve the

corneal penetration of a drug molecule and delay its elimination from the eye are discussed in

details in the present review.

Eye is most interesting organ due to its drug disposition characteristics. For ailments of the eye,

topical administration is usually preferred over systemic administration, before reaching the

anatomical barrier of the cornea, any drug molecule administered by the ocular route has to cross

the precorneal barriers. These are the first barriers that slow the penetration of an active

ingredient into the eye and consist of the tear film and the conjunctiva. The medication, upon

instillation, stimulates the protective physiological mechanisms, i.e., tear production, which exert

a formidable defense against ophthalmic drug delivery. Another serious concomitant of the

elimination of topically applied drugs from the precorneal area is the nasal cavity, with its greater

surface area and higher permeability of the nasal mucosal membrane compared to that of the

cornea. Normal dropper used with conventional ophthalmic solution delivers about 50-75µl per

drop and portion of these drops quickly drain until the eye is back to normal resident volume of

7µl. Because of this drug loss in front of the eye, very little drug is available to enter the cornea

and inner tissue of the eye. Actual corneal permeability of the drug is quite low and very small

corneal contact time of the about 1-2 mins in humans for instilled solution commonly lens than

10% Consequently only small amount actually penetrates the cornea and reaches intraocular

tissue. Controlled drug delivery to the eye is restricted due to these limitation imposed by the

efficient protective mechanism.

Ideal ophthalmic drug delivery must be able to sustain the drug release and to remain in the

vicinity of front of the eye for prolong period of time. Consequently it is imperative to optimize

ophthalmic drug delivery, one of the way to do so is by addition of polymers of various grades,

development of viscous gel, development of colloidal suspension or using erodible or non

erodible insert to prolong the precorneal drug retention. Bioadhesive systems utilized can be

either microparticle suspension or polymeric solution. For small and medium sized peptides

major resistance is not size but charge, it is found that cornea offers more resistance to negatively

charged compounds as compared to positively charged compounds.


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Following characteristics are required to optimize ocular drug delivery system:

· Good corneal penetration.

· Prolong contact time with corneal tissue.

· Simplicity of instillation for the patient.

· Non irritative and comfortable form (viscous solution should not provoke lachrymal secretion

and reflex blinking)

· Appropriate rheological properties and concentrations of the viscous system.

Although lot of alternative dosage forms have been tested to avoid the drawbacks of

conventional ophthalmic dosage form in last few years, each has been found to be deficient in

one or more ways. The focus of this review is on the recent developments in topical ocular drug

delivery systems, the characteristic advantages and limitations of each system.

1. Viscosity modifiers:

Polymer forms a back bone of a dosage form developed to prolong the precorneal residence time

of topically applied drugs. First attempt made to prolong the contact time of applied drug with

cornea was to increase the viscosity of the preparation. The viscosity modifiers used were

hydrophilic polymers such as cellulose, polyvinyl alcohol and poly acrylic acid. Polysaccharides

such as xanthun gum was found to increase the viscosity and delay the clearance of the instilled

solution by tear flow. Drugs of various solubility incorporated into these polymers to form gels.

These polymers have high molecular weight which cannot cross the biological membrane, Patton

and Robinson reported that increase in corneal penetration of ophthalmic drug would be

maximum at viscosity of about 15 to 150 cp., further increase in viscosity associated with

blurring of vision and resistance to eyelid movements. Formulations of polymers that display non

Newtonian properties offer significantly less resistance to the eyelid movements. Viscosity of

vehicles increases contact time but there is no marked sustaining effect.

Next section of review will deal in detail with two main types of polymers used in ophthalmic

drug delivery systems i.e. mucoadhesive and non mucoadhesive polymers.

2. Mucoadhesive polymers:


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Goblet cells in the cornea secrets glycoprotein which forms a thin film over cornea called as

mucin. Mucin is capable of pinking about 40-80 times its weight in water as it consist of very

large linear peptide chain to which large no of oligosaccharides chains are bound. Attractive drug

delivery is application of natural and synthetic polymers that will attach to mucin and will

remain in vicinity of mucin as long as it is present and these polymers are referred as

mucoadhesive polymers. Large range of polymers is available and various researchers have

given methods to characterize the bioadhesion of such polymers. Robinson reported that

polyanions are better in bioadhesiveness and toxicity as compare to polycations. Ditigen found

that bioadhesion directly influence ocular elimination and corneal permeation. It is found that

corneal permeation decreases as bioadhesion increases.

Following mucoadhesive polymers are used most of the times in various ophthalmic drug

delivery systems.

2.1 Polyacrylic Acid:

a) Corbopol:

Cross linked polyacrylic acid to have excellent mucoadhesive properties causing significant

enhancement in ocular bioavailability. Carbopol 934 P is high cross link water swellable acrylic

polymer with molecular weight approximately 3000000 Da. which is appropriate to use in

pharmaceutical industry. Park Robinson and Ponchel et al. reported that poly acrylic acid interact

with functional group of mucus glycol pro tien via carboxylic group. Precorneal residence of

carpool solution found to be greater than that of PVA solution when devis et al. evaluated

corneal clearance of pilocarpine in carpool 934P solution compare to that of end equiviscous non

mucoadhesive PVA solution and buffer (PBS) in the rabbits27.

Saettone et al. carried out much experiment with pilocarpine, the poly acrylic acid

(5%w/v) carbopol941P form a stable precorneal film and with less solubility. Drug duration of

stable film effect significantly increases as compare to pilocarpine . Weinreh et al. found that

suspension beta hexabol base on the poly acrylic acid provided a more constant release of

betaxol that its solution. Thermos et al. evaluated ocular bioavailibity of timolol in isoviscous

solution of PVA (PAA and timolol PAA salt). The result suggested that PAA polymer produce

lower ocular concentration that those after PVA and slower the release of timolol and resulting in

longer retention of vehicle in cunjuctivital sac by mucoadhesion31.


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Use of carpool in ophthalmic drug delivery having following advantages and disadvantages:

Gel prepared for ophthalmic administration using carbopol are more comfortable than solution,

or soluble inserts though they are instilled like ointment less blurring of vision occurred as

compare to ointment. However, disadvantages are no rate control on drug instability and it leads

to matted lids.

b) Polycarbophil:

It is cross linked poly acrylic acid polymer which is insoluble in water but swells and can

incorporate large quantity of water. Carbophil cross linked with divinyl glycol found to give

good bioadhesion as compare to conventional non bioadhesive suspention.

2.2 Carboxymethyl cellulose:

Sodium CMC found to be excellent mucoadhesive polymer. Ophthalmic gel formulated using

NaCMC, PVP and corbopol on the in vivo studies on the gel showed diffusion coefficient in

corbopol 940 1%> NaCMC 3%> PVP 23%. Recent research suggests that adhesive strength

increases as molecular weight increases up to 100000 da.

3. In situ gelling systems:

In early eighty’s concept of in situ gelling come existence these systems will have low viscosity

and will be instilled as eye drops and will change in to gel like system when in contact with

corneal fluid. This sol to gel transition can be brought about by three ways. Change in

temperature, change in pH and ion activation.

3.1 pH triggered system:

Cellulose acetate hydrogen phthalate latex, typically shows very low viscosity up to pH 5, and

forms clear gel in few seconds when in contact with tear fluid pH 7.2 to 7.4 and hence, release

contents over prolong period of time. Use of such pH sensitive latex described by Gurny et

al. the half-life of residence of CAP dispersion on corneal surface was approximately 400

seconds as compare to 40 second for solution. However, this system is associated to discomfort

to patient due to high polymer conc. and low pH of instilled solution.


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3.2 Change in temperature:

Poloxamer F127 is in the form of solution in room temp and when this solution is instilled in to

eye phase transition occurs from solution to gel at temp of eye thereby prolonging its contact

with ocular surface. Pluronic polyol represent a class of block copolymer consisting of

(polyoxyehylene and polyoxypropylene units). No of these units and their ration per mol of

polymer provide wide range of polyol with different physical and chemical properties.

3.3 Ion activation:

Gelrite is a polysaccharides, a low acetyl gellan gum shows phase transition in presence of mono

or divalent cations. Timolol bioavailability found to be superior with gel trite over equiviscous

HEC solution.

4 Colloidal systems:

Main object in optimization of ocular drug delivery is to increase the contact time of drug with

conjunctiva. Colloidal carriers like liposomes nanoparticles found to be useful to prolong the

corneal contact time and hence more and more tested in ocular drug delivery. Liposomal

suspension of idoxuridine found more efficient in the presence of herpex simplex keratitis in

rabbit as compare to idoxuridine solution. Similarly significant increase of triamicinolone in

aqueous humor found from the administration of encapsulated trimcinolone in liposomes.

However, result after administration of pilocarpine 0.1 % in liposomes in terms of intraocular

pressure found disappointing when compared with pilocarpine isotonic buffer solution. Same

result obtained with dihydrosteptomycin sulphate after administration in the form of liposomes.

From above result it is concluded that encapsulated drugs physicochemical properties have

significant influence on the effect of liposome’s. Favorable result with liposome found

essentially with lipophilic drugs. Reason for this suggested being that hydrophilic drug escape

rapidly out of the liposomes than lipophilic drugs. Charge on liposomes also influence drug

concentration in ocular tissues. Corneal epithelium is covered by negatively charged mucin and

all authors agreed that positively charged liposomes increase drug concentration in ocular

tissues.

Nanoparticles are polymeric colloidal particles ranging in size from 10-100nm. Various

polymers like polyacrylamide, polymethyl methaacrylate, albumin gelatin,


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polyalkylcynoacrylate, polylactic-co-glycolic acid, ε-caprolactone used in the preparation

of nanoparticles. First study using nanosphere done on system constituted of pilocrpine-loaded

nanosphere of polymethyl methacrylate acrylic acid copolymer by Gurny et al. developed pH

sensitive latex nanoparticles for pilocarpine and result found to be promising. In another study

binding of pilocarpine to polybutyl cynoacrylate nanoparticles enhanced the mitotic response by

about 22 to 33 %.

5 Ophthalmic insert:

Ophthalmic insert defined as sterile preparation with solid or semisolid consisting and whose

size and sharp are especially designed for ophthalmic application. They offer several advantages

as increase ocular residence, possibility of releasing drug at a slow constant rate, accurate dosing

and increased shelf life with respect to aqueous solutions. Ocusert®, pilocarpine ocular

therapeutic system is the first product marketed by Alza incorporation USA from this category.

Two types of Ocuserts® are available in the market.

Collagen shields used in animal models and in humans by Bloomfield et al. credits for first

suggesting in 1977 and in 1978 use of collagen inserts as tear substitution and as delivery system

for gentamicin.

evaluated series of commercially available polymers as possible material for the preparation of

soluble, monolithic insert. Various polymers tried in ophthalmic inserts were polyacrylic acid,

polyvinyl alcohol, silicone elastomer, hydroxy propyl cellulose, ethyl cellulose acetate phthalate

and polymethacrylic acid, hyluronic acid. Possibility using biopolymers such as fibrin chitosan

for preparation of soluble or erodible insert has been also reported in literature.

6 Ocular Iontophorosis:

Ocular iontophorosis offers drug delivery system that is fast pain less safe and result in delivery

of high concentration of drug to specific site. Studies on ocular iontophorosis of 6-hydroxy

dopamine and methylparatyrosine carried by number of investigators. Iontophoresis application

of antibiotics may enhance bactericidal activity of the antibiotics and reduce the severity of the

disease.

Existing ocular drug delivery systems are fairly primitive and inefficient, but the stage is set for

the rational design of newer and significantly improved systems. The focus of this review is on


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recent developments in topical ocular drug delivery systems relative to their success in

overcoming the constraints imposed by the eye and to the improvements that have yet to be

made. In addition, this review attempts to place in perspective the importance of

pharmacokinetic modeling, ocular drug pharmacokinetic and bioavailability studies, and choice

of animal models in the design and evaluation of these delivery systems. Five future challenges

are perceived to confront the field. These are: (a) The extent to which the protective mechanisms

of the eye can be safely altered to facilitate drug absorption, (b) Delivery of drugs to the posterior

portion of the eye from topical dosing, (c) Topical delivery of macromolecular drugs including

those derived from biotechnology, (d) Improved technology which will permit non-invasive

monitoring of ocular drug movement, and (e) Predictive animal models in all phases of ocular

drug evaluation.

The main aim of pharmacotherapeutics is the attainment of an effective drug

concentration at the intended site of action for a sufficient period of time to elicit the

response. A major problem being faced in ocular therapeutics is the attainment of an

optimal concentration at the site of action. Poor bioavailability of drugs from ocular dosage

forms is mainly due to the tear production, non‐productive absorption, transient residence time, a

nd impermeability of corneal epithelium1 Various problems encountered in poor

bioavailability of the eye installed drugs are

• Binding by the lachrymal proteins.

• Drainage of the instilled solutions;

• Lachrimation and tear turnover;

• Limited corneal area and poor corneal

• Metabolism;

• Non‐productive absorption/adsorption;

• Tear evaporation and permeability;

The poor bioavailability and therapeutic response exhibited by conventional ophthalmic

solutions due to rapid precorneal elimination of the drug may be overcome by the use

of a gel system that are instilled as drops into the eye and undergo a sol‐gel transition in the cul-de-sac For the therapeutic treatment of most ocular problems,

topical administration clearly seems the preferred route, because

for systemically administered drugs, only a very small fraction of their total dose will reach


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the eye from the general circulatory system. Even for this fraction, distribution to the inside of ey

e is further hindered by the blood‐retinal barrier (BRB). At first sight, the eye seems an

ideal, easily accessible target organ for topical treatment. However, the eye is, in fact,

well protected against absorption of foreign materials, first by the eyelids and tear‐flow and

then by the cornea, which forms the physical‐biological barrier. When any foreign

material or medication is introduced on the surface of the eye, the tear‐flow immediately

increases andwashes it away in a relatively short time. Under normal conditions, the eye can acc

ommodate only a very small volume without overflowing. Commercial eye drops have a volume

of ~30 μL, which is about the volume of the conjunctival sac in humans; however,

after a single blink, only an estimated 10 μL remains4 Consequently, there is a window of

only ~5 to 7 minutes for anytopically introduced drug to be absorbed and in many

cases, no more than 2% of the medication introduced to the eye will actually

be absorbed. be absorbed. The rest will be washed away and absorbed through the

nasolacrimal duct and the mucosal membranes of the

nasal, oropharyngeal, and gastrointestinal tract. For the remaining portion, the main biological

barrier to penetration is represented by the cornea, which is very effective. The human

cornea is composed of five tissue types with three of them, the epithelium, the endothelium,

and the inner stroma, being the main barriers to absorption.

OPTHALMIC GEL :-

Ideally an in-situ gelling system should be a low viscous, free flowing liquid to allow

reproducible administration to the eye as drop & the gel formed following phase transition

should be strong enough to with stand the shear force in the cul-de-sac & demonstrated long

residence time in the eye. In order to increase the effectiveness of the drug a dosage form should

be chosen which increase the contact time of the drug in the eye. This may then prolonged

residence time of the gel formed in situ along with its ability to release drug in sustained manner

will assit in enhancing the bioavailability, reduce systemic absorption & reduce systemic

absorption & reduce the need for frequent administration leading to improved patient

compliance.


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VARIOUS APPROACHES OF INSITU GELATION

Ideally, an insitu gelling system should be a low viscous, free flowing liquid to allow for reprodu

cible administration to the eye as drops, and the gel formed following phase transition

should be strong enough to with stand the shear forces in the cul-de-sac

and demonstrated long residence times in the eye. In order to

increase the effectiveness of the drug a dosage form should be chosen which increases the

contact time of the drug in the eye. This may then prolonged residence time of the gel

formed insitu along with its ability to release drugs in sustained manner will assist in enhancing t

he bioavailability, reduce systemic absorption and reduce the need for frequent administration

leading to improved patient compliance.

Depending upon the method employed to cause sol to gel phase transition on the

ocular surface, the following types of systems are recognized:

• pH‐triggered systems: cellulose acetate phthalate(CAP) latex, carbopol, polymethacrilic

acid(PMMA), polyethylene glycol (PEG), pseudolatexes.

•Temperature dependent systems: chitosan, pluronics, tetronics, xyloglucans, hydroxypropylmet

hyl cellulose or hypromellose (HPMC).

•Ion‐activated systems (osmotically induced gelation): gelrite, gellan, hyaluronic acid, alginates.

• UV induced gelation

• Solvent exchange induced gelation.

These (liquid) vehicles undergo a viscosity increase upon instillation in the eye, thus favouring

precorneal retention. Such change inviscosity can be triggered mainly by a change in temperature

, pH or electrolyte composition. pHtriggered insitu gelation: Polyacrylic acid (Carbopol 940)

is used as the gelling agent in combination with hydroxypropyl‐methylcellulose (Methocel

E50LV) which acted as a viscosity enhancing agent. The formulation with pH‐triggered

insitu gel is therapeutically efficacious, stable, non‐irritant and provided sustained release

of the drug for longer period of time

than conventional eye drops. Another example cellulose acetate phthalate (CAP) is a polymer

undergoing coagulation when the original pH of the solution (4.5) is raised to 7.4 by the tear flui

d7‐9.Temperaturetriggeredinsitugel: The system is designed to use Poloxamer as a vehicle for op

hthalmic drug delivery using insitu gel formation property. The gelation temperature of graft

copolymers can be determined by measuring the temperature at which immobility of the


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meniscus in each solution was first noted. The bioadhesive and thermally gelling of these

graft copolymers expected to be an excellent drug carrier for the prolonged delivery

to surface of the eye. Other example Poloxamer‐407 (a polyoxyethylenepolyoxypropylene

block copolymer, Pluronic F‐127®) is a polymer with a solution viscosity that increases when its

temperature is raised to the eye temperature10‐11 Ionactivated insitu gelation: Alginate

(Kelton) is used as the gelling agent in combination with HPMC (Methocel E50Lv)

which acted as a viscosity‐enhancing agent. Gelrite gellan gum, a novel ophthalmic

vehicle that gels in the presence of mono or divalent cations, present in the lachrymal

fluid can be used alone and in combinations with sodium alginate as the gelling agent.

Worked reviewed in the field of insitu gel:

Over the last decades, an impressive number of novel temperature, pH, and ion induced insitu for

ming solutions have been described in the literature. Each system has its own advantages and

Drawbacks.

The choice of aparticular hydrogel depintrinsic properties and envisaged therapeutic use. oral

candidiasis using pH‐triggered system containing carbopol 934P (0.2‐1.4% w/v) and ion‐triggered system using gellen gum (0.1‐0.75% w/v) along with HPMC E50 LV.

Formulations were evaluated for gelling capacity, viscosity, gel strength, bio‐adhesive forces, spreadability, microbiological studies and in vitro release. The optimized

formulation was able to release the drug up to 6 h. The formulation

containing gellen gum showed better sustained release compared to carbopol based gels

Formulated and evaluated insitu gels for ciprofloxacin based on the concepts of pH‐triggered in-

situ gelation, thermo reversible gelation and Ion activated system. Poly acrylic acid

(Carbopol 940) was used as the gelling agent in combination of hydroxypropyl

methylcellulose, which acted as a viscosity‐enhancing agent. (PH-triggered system). Pluronic F‐127 (14%) was used as the thermal reversible gelation in combination of HPMC (1.5%)

incorporation of HPMC was to reduce the concentration of pluronic required for insitu

gelling property, with 25% w/w pluronic F‐127 reported to form good gels. Gellan gum

(Gelrite) is an anionic exocellular polysaccharide by the bacterium Pseudomonas elodea,


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having the characteristic property cation‐induced gelation (0.6%). The developed

formulation was therapeutically efficacious, stable, non irritant and provided sustained

release of the drug over six hours period, but Gelrite formulation showing long duration

of release followed by combination of carbopol, HPMC and pluronic F‐127 and

HPMC. The developed system is thus a viable

alternative to conventional eye drops. Prolonged the precorneal resident time and improves ocula

r bioavailability of the drug; Pluronic F127‐g‐poly (acrylic acid) copolymers were studied as in-

situgelling vehicle for ophthalmic drug delivery system. The rheological properties and invitro

drug release of Pluronic‐g‐PAA copolymer gels were investigated. The rheogram and in

vitro drug release studies indicated that the drug release rates decreased as acrylic

acid/Pluronic molar ratio and copolymer solution concentration increased. But the drug concentr

ation had no obvious effect on drug release. The release rates of the drug from such copolymer

gels were mainly dependent on the gel dissolution. In vivo resident experiments showed the

drug resident time and the total resident amount in rabbit’s conjunctiveal sac

increased by 5.0 and 2.6 folds for insitugel, compared with eye drops. The decreased loss angle a

t body temperature and prolonged precorneal resident time

also indicated that the copolymer gels had bioadhesive properties.These in vivo experimental

results, along with the rheological properties and in vitro drug release studies,

demonstrated that insitugels containing Pluronic‐g‐PAA copolymer may significantly prolong

drug resident time and thus improve bioavailability. Pluronic‐g‐PAA copolymer can be a promisi

ng insitugelling vehicle for ophthalmic drug delivery system. prepared and evaluated sustained o

cular drug delivery from a temperature and pH triggered novel insitu gel system using

Pluronic F‐127 (a thermo sensitive polymer) in combination with chitosan (pH‐sensitive

polymer also acts as permeation enhancer) was used as gelling agent with timolol maleate

investigated a novel copolymer, poly (N‐isopropylacrylamide)‐chitosan (PNIPAAm‐CS),

for its thermosensitive insitu gel‐forming properties and potential utilization for ocular drug deliv

ery. The thermal sensitivity and low critical solution temperature (LCST) were determined by

the cloud point method. PNIPAAm‐CS had a LCST of 32°C, which is close to the surface tempe

rature of the eye. The in vivo ocular pharmacokinetics of timolol maleate in PNIPAAm‐CS

solution were evaluated and compared to that in conventional eye drop solution by using

rabbits according to the micro dialysis method. The results suggest that PNIPAAm‐CS is


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a potential thermo sensitive insitu gel‐forming material for ocular drug delivery, and it

may improve the bio‐availability, efficacy, and compliance of some eye drugs

CONVENTIONAL DELIVERY SYSTEMS:

Eye Drops: Drugs which are active at eye or eye surface are widely administered in the form

of Solutions, Emulsion and Suspension. Generally eye drops are used only for anterior segment

disorders as adequate drug concentrations are not reached in the posterior tissues using this drug

delivery method. Various properties of eye drops like hydrogen ion concentration, osmolality,

viscosity and instilled volume can influence retention of a solution in the eye. Less than 5

Percent of the dose is absorbed after topical administration into the eye. The dose is mostly

absorbed to the systemic blood circulation via the conjunctival and nasal blood vessels. Ocular

absorption is limited by the corneal epithelium, and it is only moderately increased by prolonged

ocular contact. The reported maximal attainable ocular absorption is only about 10 Percent of the

dose.When eye drops is administered in the inferior fornix of the conjunctiva, very small amount

of the dose reaches to the intraocular tissues and major fraction of the administered drug get

washed away with the lachrymal fluid or absorbed systemically in the nasolacrimal duct and

pharyngeal sites..

Ointment and Gels:

Prolongation of drug contact time with the external ocular surface can be achieved using

ophthalmic ointment vehicle but, the major drawback of this dosage form like, blurring of vision

and matting of eyelids can limits its use. Pilopine HS gel containing pilocarpine was used to

provide sustain action over a period of 24 hours. A number of workers reported that ointments

and gels vehicles can prolong the corneal contact time of many drugs administered by topical

ocular route, thus prolonging duration of action and enhancing ocular bioavailability of drugs.

Ocuserts and Lacrisert:

Ocular insert (Ocusert) are sterile preparation that prolong residence time of drug with a

controlled release manner and negligible or less affected by nasolacrimal damage.Inserts are

available in different varieties depending upon their composition and applications. Lacrisert is a

sterile rodshaped device for the treatment of dry eye syndrome and keratitis sicca and was

introduced by Merck, Sharp and Dohme in 1981. They act by imbibing water from the

cornea and conjunctiva and form a hydrophilic film which lubricates the cornea


16

Ocular disorders:

According to location of diseases, ocular disorders are grouped as periocular and intraocular.

Periocular disorders:

Blepharitis: An infection of lid structures (usually by staphylococcus aureus) with concomitant

seborrhoea, rosacea, a dry eye and abnormalities in lipid secretions

Conjunctivitis: The condition in which redness of eye and presence of a foreign body sensation

are evident. There are many causes of conjunctivitis but the great majority are the result of

acute infection or allergy. Kertitis: The condition in which patient have a decreased

vision ,ocular pain, red eye, and often a cloud / opaque cornea .It is mainly caused by

bacteria ,viruses, fungi etc. Trachoma: This is caused by the organism chalmydia trachoma is; it

is the most common cause of blindness in North Africa and Middle East.

Intraocular disorders:

These conditions are difficult to manage and include intraocular infections: i.e. infections in the

inner eye, including the aqueous humour, iris, vitreous humour and retina.

Glaucoma: More than 2% of the population over age 40 years have this disorder in which an

increased intraocular pressure greater than 22 mg Hg ultimately compromises blood flow to

retina and thus causes death of peripheral optic nerves.

Routes of delivery: There are three main routes commonly used for administration of drugs to

the medication to the eye .Introducing the drug directly to the conjuctival sac localizes drug

effects, facilitates drug entry that is otherwise hard to achieve with systemic delivery and avoids

first pass metabolism.The intraocular route is more difficult to achieve practically. Now

research is concentrating on the development of intravitreal injections and use of intraocular

implants to improve delivery to eye.

In systemic route, several studies have shown that some drugs can distribute into ocular tissues

following systemic administration. Oral administration of carbonic anhydrase inhibitors

including acetazolamide, methazolamidedemonstrates the capacity of a systemic drug to

distribute into the cilliary process of eye.

Pathways of drug absorption: The main route forintraocular absorption is across the cornea.

Two features, which render the cornea an effective barrier to drug absorption, are its small


17

surface area and its relative impermeability. Most effective penetration is obtained with drugs

having both lipophilic and hydrophobic properties.


18

Anatomical and physiological features of the eye


19

The eye is a unique organ for drug delivery. Many excellent reviews can be found in the

Literatures that describe the anatomical and physiological features of the eye, written from the

Perspective of drug delivery4-10.Many of these anatomical and physiological features interferes

with the fate of the administered drug. First and foremost are blinking, tear secretion, and

nasolacrimal drainage. Lid closureupon reflex blinking protects the eye from external aggression.

Tears permanently wash the surface ofthe eye and exert an anti-infectious activity by

thelysozyme and immunoglobulin’s they contain. Eventually the lachrymal fluid is drained down

the nasolacrimal pathways, then pharynx and esophagus. This means that a portion of the drug is

Systematically delivered as if by the oral route. During administration, a part of an aqueous drop

instilled in the patient’s cul-de-sac is inevitably lost by overflow/drainage, since the conjunctival

pouch can accommodate only approximately 20 μL of added fluid.

Drug delivery to the internal regions of the eye

1. Eye Penetration of Drugs Administered Locally to the Eye:

If the drug is not intended to act on the external surface of the eye, then the active ingredient has

to enter the eye. There is consensus that the most important route is transcorneal; however, a

noncorneal route has been proposed and may contribute significantly to ocular bioavailability of

some ingredients, e.g., timolol and insulin14. In addition, the sclera has also been shown to have

a high permeability for a series of blocking drugs. Precorneal tear film produced by tear secretion

keeps the cornea moist, clear, and healthy and is spread by the motion of eyelids during blinking.

Drugs acting on tear secretion, physicochemical status of the tear film, and blinking can modify

transcorneal drug permeation


20

2. Eye penetration of systemically administered drugs:

It is of interest to reflect on the eye penetration of systemically administered drugs, mostly anti

infectious and anti-inflammatory drugs. There are blood-eye barriers. Aqueous humor is

produced by the ciliary epithelium in the ciliary processes. It is frequently named an ultra filtrate,

since the ciliary epithelium prevents the passage of large molecules, plasma proteins, and many

antibiotics. Some molecules can be secreted in aqueous humor during its

formation .Inflammation associated with injury, infection, or an ocular disease, e.g., uveitis,

disrupts the blood–aqueous humor barrier and drugs enter the aqueous humor and reach the

tissues of the anterior segment. There is a blood retina barrier and there is one between blood and

vitreous humor complicated by the high viscosity of the latter, which prevents diffusion of the

drug sin the posterior part of the eye. Delivery of drugs to the posterior pole and to the retina is

extremely difficult.

GHEE:-


21

Ghrita is one of the Ayurvedic drugs that contain ghee as the base to dissolve or extract or hold

the active therapeutic principles from the ingredients. Ghritas are medicated ghee preparations

containing the fat-soluble components of the ingredients used in these preparations. The

principle of preparation is the protracted boiling of ghee with prescribed kashayas (decoctions)

and kalkas (a fine paste of the drug/drugs) to dehydration or near dehydration thereby effecting

the transference of the fat soluble principles to the ghrita, from the drug ingredients or kashayas

or swarasas as the case may be according to the formulation. In India, preservation of milk and

milk products is primarily achieved by heat induced desiccation. Ghee is obtained by

clarification of milk fat at high temperature. Ghee is almost anhydrous milk fat and there is no

similar product in other countries. It is by far the most ubiquitous indigenous milk product and is

prominent in the hierarchy of Indian dietary. Being a rich source of energy, fat soluble vitamins

and essential fatty acids, and due to long shelf life at room temperature (20 to 40C), 8070 of ghee

produced is used for culinary purposes. The remaining 2070 is used for confectionery, including

sma/l amounts consumed on auspicious occasions like religious ceremonies (22).Since buffalo

milk constitutes more than 5570 of the total milk production in India and because of its higher fat

content (6-770), ghee is manufactured mostly from buffalo milk. Due to lack of carotenoids in

buffalo milk, ghee prepared from milk is white unlike cow ghee which has a golden yellow

color. Because of its pleasing flavor and aroma, ghee has always had a supreme status as an

indigenous product in India.

Physicochemical Characteristics

Chemically, ghee is a complex lipid of glycerides (usually mixed), free fatty acids,

phospholipids, sterols, sterol esters, fat soluble vitamins, carbonyls, hydrocarbons, carotenoids

(only in ghee derived from cow milk), small amounts of charred casein and traces of calcium,

phosphorus, iron, etc. It contains not more than. 370 moisture. Glycerides constitute about 9870

of the total material. Of the remaining constituents of about 270, sterols (moStly cholesterol)

occur to the extent of about .5~. Ghee has a melting range of 28 to 44 C. Its butyro fractometer

reading is from 40 to 45 at 40 C. The saponification number is not less than 220. Ghee is not

highly unsaturated, as is evident from its iodine number of from 26 to 38. The Reichert-Meissl

number (RM) of cow ghee varies from 26 to 29 whereas goat ghee is slightly less. Sheep and

buffalo ghee on the other hand, have higher RM numbers of about 32. In general, ghee is


22

required to have a RM number of not less than 28. Itis, however, of interest that ghee from milk

of animals fed cotton seeds has much lower RM numbers of about 20. Polenske number for cow

ghee is higher (2 to 3) than buffalo ghee (1 to 1.5). No significant seasonal variations have,

however, been recorded for their fat conscants. The fatty acid profile of glycerides of ghee is

very complex and still not completely elucidated. Recently, Ramarnurthy and Narayanon

published the fatty acid composition of buffalo and cow ghee. Layer formation is typical in ghee

if stored above 20 C. The chemical properties of these layers are significantly different as shown

by Singhal et al (20) (Table 1). Significant differences are evident in the RM numbers of these

layers. The liquid layer always has a higher RM number than the semisolid layers.

Preparation

Ghee making in India is mostly a home industry. Substantial amounts come from villages

where it is usually prepared by the desi method. Recently, industry has manufactured improved

ghee of more uniform quality. However, it still constitutes only a small fraction (a few thousand

tons only) of the total annual production (450,000 metric tons) in India. In general, ghee is

prepared by four methods, namely, desi, creamery butter, direct cream and pre-stratification

methods. The essential steps involved in the preparation of ghee by these methods are outlined in

Figures 1 to 4 (6, 15). Basically, the high heat applied to butter or cream removes moisture. Both

are usually clarified at 110 to 120 C. However, in southern India clarification is at 120 to 140 C.

The desi method consists of churning curdled whole milk (dahi) with an indigenous corrugated

wooden beater, separating the butter, and clarifying it into ghee by direct open pan heating.

Earthenware vessels are used to boil milk and ferment it with a typical culture to convert it to

dahi which in turn is churned to separate the butter. The creame~3r butter and direct cream

methods are more suitable for commercial operations because less fat is lost. Direct cream

method is reportedly most economical for preparing ghee and the product has better keeping

quality (9). In the pre-stratification method, advantages such as economy in fuel consumption

and production of ghee with low acidity and comparatively longer shelf life, have been claimed .

However, this method has not been adopted by industry. Desi method accounts for more than

97% of ghee manufactured.

Recently, continuous ghee making equipment has been fabricated at the National Dairy

Research Institute at Karnal . The equipment is a three-stage pressurized, swept surface

separator. This mechanical process is more sanitary than existing methods.


23

Quality of Ghee

The quality of ghee depends on milk, cream, dahi or butter, methods of preparation, temperature

of clarification, storage conditions, and type of animal feed. These factors in turn will determine

the physicochemical characteristics of ghee. The principal measurements of ghee quality are:

peroxide value, acidity, and flavor.

Peroxide value and acidity.

The quality of ghee on storage has been measured by acid and peroxide values (10). However,

peroxide value varies considerably at the organoleptic threshold of rancidity. More recently, that

the thiobarbituric acid value (TBA value) is a more reliable index of oxidative rancidity of ghee.

They found that the TBA value of buffalo ghee was always higher than that of cow ghee. Flavor.

The most important factor controlling the intensity of flavor in ghee is the temperature of

clarification . Ghee prepared at 120C or above has an intense flavor which is usually referred to

as cooked or burnt. In contrast, ghee prepared at around 110 G has a somewhat mild flavor, often

referred to as curd. The desi method generally produces ghee with the most desirable flavor. The

acidity of the cream or butter affects the flavor of ghee. Sweet cream-butter yields ghee with a

fiat flavor whereas cream or butter having an acidity of .15 to .25% (lactic acid) as in ripened

cream-butter, produces ghee with a more acceptable flavor. However, the rate of deterioration in

the market quality of ghee is least in ghee from unripened cream-butter and most in that prepared

from ripened cream-butter. The flavor of stored ghee is influenced by the method of preparation

and by temperature of clarification. In ghee made at 110 C, the original flavor is maintained for

several months, but once deterioration begins, market quality is lost quicker than in ghee

prepared at the higher temperatures of clarification. Flavor in ghee is retained longer when butter

contains 1% NaCI. Elucidation of complex chemical entities responsible for ghee flavor is being

pursued at this Institute (2) and sponsored by U.S. Public Law 480 funds. Some of the important

findings to date are reported. There is a general similarity in the gross patterns of volatile

carbonyls isolated from differently produced ghee. Of the 11 earbonyls in most of the ghee

produced, six have been tentatively identified as propanone, butanone- 2, pentanone-2,

heptanone-2, octanone-2 and nonanone-2. Small but significant differences in the quality and

quantity of volatile earbonyls in different types of ghee have been reported. The use of ripened

cream butter in the preparation of ghee improves the flavor, but the impact on the pattern of

carbonylic compounds in ghee appears to be less marked. About 95% of the carbonyls in ghee


24

are nonvolatile. Cow ghee contains more volatile carbonyls. The total carbonyls of buffalo ghee

are higher than that of cow ghee irrespective of the method of preparation and temperature of

clarification. The ketoglycerides constitute 50 to 60% of the total carbonyls in ghee, buffalo ghee

(4.4 /~motes/g) having a higher proportion than cow ghee (2.4 /~moles/g). Oct-2-enal and dec-2-

enal are the main alk- 2-enals in the volatile as well as monocarbonyls in ghee. The patterns of

alkanals frem cow and buffalo ghee are similar and consist of ethanal, pentanal, hexanal,

heptanal, octanal, nonanal,decanal, undecana] and dodecanal.

Changes on Storage

Ghee undergoes physicochemical changes, dependent primarily on the temperature of storage.

Crystallization occurs with the formation of solid, semi-solid and liquid layers. Ghee (cow and

buffalo) kept either in a metal or glass container at 20 C or below, solidifies uniformly with fine

crystal (3). Above 20 C and below 30 C, solidification is a loose structure. The liquid portion had

a significantly higher RM number than the granular solid or hard flaky portion of the same ghee.

A similar trend in the iodine number in these layers also occurs. Detailed investigation on layer

formation by Singhal et al (18) suggested that it would be preferable to store ghee below 20 C to

avoid layer formation. Ghee stored at high temperature is also susceptible to oxidative

deterioration, rancidity, and off flavor. Due to inadequate storage facilities in India, much ghee

loses its market acceptability. Shelf life of ghee is also dependent on the method of preparation.

The keeping quality of desi ghee is better than that of direct cream or creamery butter ghee.

Ramamurthy et al. claim that milk phospholipids in ghee improves its shelf life. Ghee having

more residues, which is a source of phospholipids, has a longer storage life.

Packaging and Marketing

Packing of ghee is permitted ordinarily in 17, 4, 2 and i kg tinned cans . Excepting 17 kg cans,

others must contain the net weight of ghee, e.g. 4, 2, or 1 kg. Permission is also given to pack

ghee in 1 kg and half kg returnable glass bottles. Special permission of the Agricultural

Marketing (Agmark) Adviser to the Government of India is necessary for packing in any other

size package. Most ghee is marketed in 4-gallon tin containers. Cans are filled to brim with no

air space to improve storage quality. Antioxidants like butyl hydroxyl anisole (BttA) are

permitted to prolong shelf life. The agencies engaged in India in ghee assembling and

distribution are producers, village merchants, itinerant traders, cooperative societies, state

dairies, retailers, and some private and public dairy enterprises.


25

Ghee Grading and Standards

The grading of ghee in India is in general done by Agmark Adviser to the Government of India

under provisions of Agricultural Produce (Grading and Marketing) Act of 1937. All ghee graded

by Agmark has to be pure and prepared from only cow and buffalo milk. Regional specifications

also exist in such grading due to variation in compositional properties of ghee influenced by the

type of animal feed.

The International Dairy Federation (IDF) has recently drafted a standard for ghee whereby it is

defined as a product exclusively obtained from milk, cream, or butter from various animal

species, by processes which result in almost the total removal of moisture and solids-not-fat. It

must consist of a mixture of higher melting point fats in liquid form. It should contain not more

than 3% moisture. Milk fat (mostly glycerides) constitutes 99.5% of the total solids. This IDF

standard is being examined for its final acceptance.

Cotton Tract Ghee

During certain seasons large quantities of cotton-seeds are fed to lactating animals in cotton

growing areas (Saurashtra and Madhya Pradesh). The composition of ghee prepared from the

milk of such animals differs significantly from that from milks of animals fed on a concentrate

mixture of oilcakes, grains, bran, etc. Dastur proposed a special standard for ghee from such

areas and it is often referred to as cotton tract ghee. The RM number requirement for cotton tract

ghee is lower (e.g. 20) than that for ghee from other areas.

Ghee Adulteration and its Detection

It is a common practice to adulterate ghee with cheaper vegetable and animal body fats.

Hydrogenated vegetable fats, popularly known as vanaspati ghee in this country, have often been

used to adulterate ghee. However, the legal requirement that all vanaspati ghee marketed in this

country must contain a specified amount of sesame oil which can be easily detected by Bauduin

test 1. Bomer's 2 phytosterol acetate test based on the structural differences between phytosterols

(e.g. sitosterol) and animal sterols (e.g. cholesterol) has also been occasionally used. More

recently, Ramamurthy et al (12) reported a thin layer chromatographic method for detecting ghee

adulteration with vegetable oils and fats.

Detection of animal body fats in ghee is more difficult. An opacity method based on differential

melting point ranges for common animal body fats (43 to 50 C) and ghee (30 to 44 C) has been

developed by Singhal et al (20). It is claimed to detect 5% animal body fats in ghee. However,


26

this test is useless for cotton tract ghee which has a melting point near that of animal body fats.

The methylene blue reduction test developed by these authors (19), overcame this difficulty

because only cotton tract ghee decolorizes methylene blue.

Butteroil Versus Ghee

The main differences between ghee and butteroil have been recently summarized by Ganguli (8).

Butteroil has a bland flavor whereas ghee has a pleasing flavor. Ghee has less moisture, contains

more protein solids and differs in fatty acid and phospholipid as compared to butteroil. Butteroil

is prepared by melting butter at not exceeding 80 C, whereas ghee is manufactured at 100 to 140

C. Butteroff can be reconstituted with skimmilk powder whereas ghee cannot be.


27

Drug profile:

ATROPINE SULPHATE

Atropine is the best-known member of a group of drugs known as muscarinic antagonists, which

are competitive antagonists of acetylcholine at muscarinic receptors. This naturally occurring

tertiary amine was first isolated from the Atropa belladonna plant . Although atropine earlier

enjoyed widespread use in the treatment of peptic ulcer, today it is mostly used in resuscitation,

anaesthesia, and ophthalmology, usually as the more soluble sulphate salt. By competitively

blocking the action of acetylcholine at muscarinic receptors, atropine may act as a specific

antidote. As such, it may also be used to counteract adverse parasympathomimetic effects of

pilocarpine, or neostigmine administered in myasthenia gravis. It is a specific antidote for the

treatment of poisoning with organophosphorus and carbamate insecticides and

organophosphorus nerve agents. Although other anticholinergic agents (such as dexetimide) with

different distribution kinetics may have advantages in rodent models, the role of atropine in the

treatment of organophosphate

poisoning is essentially unchallenged, though there is controversy concerning the dose of

atropine necessary for optimal therapy in organophosphate poisoning. Atropine is also useful in

treating muscarine poisoning following ingestion of fungi of the Clitocybe and Inocybe species.

If the dose of atropine is titrated correctly, it has few serious side effects when used in

organophosphate poisoning. Patients, who are hypoxic, however, are at risk of developing

ventricular tachycardia or fibrillation if given atropine. It is important, therefore, to correct

hypoxia by clearing airways, administering oxygen and, if necessary, mechanically ventilating

the patient before giving atropine

Name and chemical formula

Names:

Atropine and atropine sulphate

Synonyms

Atropine sulphate

Atropina solfato (Italy); atropina sulfato (Spain, Argentina); atropine sulphate (USA); atropin

siran (Czech); atropinsulfas; atropinsulfat (Germany); sulphate d’atropine (France); 1-alpha-H,5-


28

alpha-Htropan- 3-alpha-OL-(±)-tropate (ester), sulfate (2:1) salt; dl-tropanyl-2-hydroxy-1-

phenylpropionate sulphate

IUPAC name

Atropine sulphate

benzeneacetic acid, alpha- (hydroxymethyl)-8-methyl-8-azabicyclo{3.2.1}oct-3-yl ester endo -

(±)-,compounds, sulfate (2:1) (salt)

CAS number:

55-48-1 (atropine sulphate anhydrous) (USP, 2002).

Atropine sulphate monohydrate (C17H23NO3)2,H2SO4 .H2O (Parfitt, 1999)

Physico-chemical properties

Melting point.

Atropine sulphate monohydrate:

This salt has a melting point of 190 to 194 °C

Physical state

Atropine sulphate:

Atropine sulphate occurs as odourless, very bitter, colourless crystals or white crystalline powder

Solubility

Atropine sulphate monohydrate

Atropine sulphate is very soluble in water. One gram dissolves in 0.4 ml water. One gram

dissolves in 5 ml cold alcohol and 2.5 ml boiling alcohol, in 2.5 ml glycerol, 420 ml chloroform

and 3,000 ml ether.

Optical properties:

Atropine sulphate

atropine sulphate is almost inactive optically

pH

Atropine sulphate:

A 2% solution in water has a pH of 4.5 to 6.2

Stability in light

Atropine sulphate:


29

Atropine sulphate is slowly affected by light. It should be protected from light and stored in airtight containers

Reactivity.

Atropine sulphate:

Atropine sulphate effloresces when exposed to dry air . When heated to decomposition, toxic

fumes of oxides of nitrogen and sulphide are emitted.

Pharmaceutical incompatibilities

Atropine sulphate

Atropine sulphate is reported to be physically incompatible with noradrenaline bitartrate,

metaraminol bitartrate and sodium bicarbonate injections. A haze or precipitate may form within

15 minutes when the injection is mixed with methohexital sodium solution. Immediate

precipitation occurs when cimetidine and pentobarbital sodium together are mixed with atropine

sulphate in solution; while aprecipitate will form within 24 hours if atropine sulphate is mixed

with pentobarbital sodium alone Thiopental sodium and atropine sulphate injected together at Y-

sites will form white particles in the solution immediately . A haze will form in 24 hours then a

precipitate at 48 hours if flucloxacillin sodium and atropine sulphate are stored together at 30 °C,

while no change is seen at 15°C.

Incompatibilities between atropine sulphate and hydroxybenzoate preservatives have occurred,

with a total loss of atropine in 2-3-weeks . Atropine sulphate is incompatible with other alkalis,

tannin, salts of mercury or gold, vegetable decoctions or infusions, borax, bromides and iodides.

Proprietary names and manufacturers

Atropine sulphate:

Atropair® (Pharmafair, USA); Atropine Aguettant®( Aguettant, France),

Atropine Meram® (Cooper, France); Atropine Opthadose®(Ciba-Geigy, Belgium); Atropine

SDUFaure®(Ciba Vision, Suisse); Atropinium sulfuricum Streuli®(Streuli, Suisse);

Atropinum sulfuricum AWD®(ASTA Medica, Denmark); Atropisol®(Ciba Vision, Canada,

Iolab, USA);

Atropocil®(Edol, Portugal); Atropt®(Sigma, Australia); Atrosol®(Adilna Turkey); I-

Tropine®(Americal, USA); Isopto Atropine®(many countries); Liotropina®(SIFI, Italy);

Midrisol®(Abdi Ibrahim, Turkey); Noxenur S®(Galenika, Denmark);


30

Sal-Tropine®(Hope, USA);Skiatropine®(Cjauvin, France, Suisse); Stellatropine®(Stella,

Belgium, Luxembourg); Tropyn Z®(Zafiro, Mexico)

Pharmaceutical formulation and synthesis

Manufacturing processes

Atropine is usually prepared by extraction from the plants Atropa belladonna (deadly

nightshade), Datura stramonium (Jimson weed) or Duboisia myoporoides . This extracted

atropine is a combination of D and L hyoscyamine. Both these isomers may bind to muscarinic

receptors although the pharmacological activity is thought to be due almost entirely to L

hyoscyamine .

Pharmaceutical formulation

Atropine sulphate

Atropine sulphate is available as a sterile solution in normal saline or water for injection from

several manufacturers. The preservatives parabens and sulphites, may be found in injectable

products. Atropine sulphate is usually available in concentrations of 0.25-0.5 mg/ml, although

some countries, such as Portugal and Germany, have a 10 mg/ml solution for use in

organophosphate poisoning. Atropine sulphate injections may be adjusted to a pH of 3 to 6.5

with sulphuric acid.

Oral forms (tablets) are also available .

atropine sulphate

Assay (USP, 2002)

1 g of atropine sulphate, accurately weighed, is dissolved in 50 ml of glacial acetic acid, then

titrated with 0.1 N perchloric acid VS, determining the endpoint potentiometrically. Each ml of

0.1 N perchloric acid should be equivalent to 67.68 mg of (C17H23NO3)2 . H2SO4.

Assay (BP, 2000)

0.500 g of atropine sulphate is dissolved in 30 ml of anhydrous acetic acid R, warming if

necessary. The solution is cooled then titrated with 0.1M perchloric acid and the end-point

determined potentiometrically (2. 2. 20). 1 ml of 0.1M perchloric acid should be equivalent to

67.68 mg of C34H48N2O10S.


31

Assay (PPRC, 2000)

0.5 g of accurately weighed atropine sulfate is dissolved in a mixture of 10 ml of glacial acetic

acid and 10 ml of acetic anhydride, one to two drops of crystal violet is added and the solution

titrated with perchloric acid (0.1 mol/L) VS until the color is changed to pure blue. A blank

determination is performed and any necessary corrections made. Each ml of perchloric acid (0.1

mol/L) VS should be equivalent to 67.68 mg of (C17H23NO3)2 .H2SO4.

Limit of other alkaloids (USP, 2000)

150 mg atropine sulphate is dissolved in 10 ml water. To 5 ml of this solution is added a few

drops of platinic chloride TS: no precipitate should be formed. To the remaining 5 ml of the

solution, 2 ml of 6 N ammonium hydroxide is added and shaken vigorously: a slight opalescence

may develop but no turbidity should be produced.

Limit of foreign alkaloids and decomposition products (BP, 2000)

The substance should be examined by thin-layer chromatography (2. 2. 27) using silica gel G R

as the coating substance. Solutions should be made up as follows: Test solution. 0.2 g of the

substance to be examined is dissolved in methanol R and diluted to 10 ml with the same solvent.

Reference solution (a). 1 ml of the test solution is diluted to 100 ml with methanol R.

Reference solution (b). 5 ml of reference solution (a) is diluted to 10 ml with methanol R.

To the plate is applied separately 10 μl of each solution. These are developed over a path of 10

cm using a mixture of 90 volumes of acetone R, 7 volumes of water R and 3 volumes of

concentrated ammonia R. The plate is dried at 100 °C to 105 °C for 15 minutes. It is allowed to

cool then sprayed with dilute potassium iodobismuthate solution R until the spots appear. Any

spot in the chromatogram thus obtained with the test solution, apart from the principal spot,

should not be more intense than the spot in the chromatogram obtained with reference solution

(a) (1.0 per cent) and not more than one such spot should be more intense than the spot in the

chromatogram obtained with reference solution (b) (0.5%).

Limit of apoatropine (BP, 2000)

0.10 g atropine sulphate is dissolved in 0.01M hydrochloric acid and diluted to 100 ml with the

same acid. The absorbance is determined (2. 2. 25) at 245 nm.


32

Atropine sulphate injection

Chromatographic methods of assay are described in USP, 2002 and BP, 2000.

The pH of atropine sulphate injection USP, 2002 should be between 3.0 and 6.5. It should

contain not more than 55.6 USP Endotoxin units per milligram of atropine sulfate and it should

meet the standard requirements for USP, 2002 injections.

Shelf life

Atropine sulphate

Atropine sulphate should be stored in single or multiple-dose containers, preferably glass, at a

temperature of less than 40 °C (preferably between 15 to 30 ° C). It should be protected from

light and stored in airtight containers.(USP, 2002). Freezing should be avoided .The shelf-life is

24 months from the date of manufacturing if kept under the above conditions

General properties

7.1. Mode of antidotal activity

Atropine is a muscarinic cholinergic blocking agent. It competitively blocks parasympathetic,

Postganglionic nerve endings from the action of acetylcholine and other muscarinic agonists.

Atropinic drugs have little effect at nicotinic receptor sites. Large doses of atropine produce only

partial block of autonomic ganglia and have almost no effect at the neuromuscular junction.

Small doses of atropine depress sweating and salivary and bronchial secretion. Atropine is

particularly useful in relieving bronco constriction and salivation induced by anticholinesterases.

Doses required to inhibit gastric secretion are invariably accompanied by dry mouth and ocular

disturbances. At higher doses, the heart rate increases as the effects of vagal stimulation are

blocked. When given alone atropine has little effect on blood pressure, although it can block

completely the hypotensive and vasodilatory effects of choline esters. Larger doses decrease the

normal tone and amplitude of contractions of the bladder and ureter, thereby inhibiting

micturition. Atropine inhibits both the tone and motility of the gut, reducing peristalsis. Unlike

scopolamine, small doses of atropine have little depressant action on the central nervous system.

However, in toxic doses, atropine initially causes central excitation (exhibited as restlessness,

confusion, hallucinations, and delirium) followed by central depression with coma and death.

Both atropine and scopolamine shift the EEG to slow activity, reducing the voltage and


33

frequency of the alpha rhythm. Atropine normalizes increased EEG activity due to isoflurophate.

For many years, the central anticholinergic effects of the belladonna alkaloids in reducing tremor

were the mainstay of therapy for Parkinson's disease.

Large doses of atropine impair accommodation, causing dilation of the pupil and blurred vision.

The normal pupillary response to light or upon convergence may be completely abolished. These

ocular effects may be seen after oral, systemic, or local administration of the drug (Weiner,

1985). The peripheral antimuscarinic effects of atropine may not be the only antidotal property

of the drug in organophosphate poisoning. Atropine may also be of value in treating acute

dystonic reactions occasionally observed in acute organophosphate poisoning. Patients with

extrapyramidal signs have been noted to have abnormally low plasma and red blood cell

cholinesterase activities, producing an excess of acetylcholine relative to dopamine. However,

there is little clinical evidence available on the possible anticonvulsive effects of atropine in man.

Pharmacodynamics

This section will review briefly animal work relevant to the use of atropine, whether

administered alone or in combination with an oxime, in the management of organophosphate

poisoning. It is necessary, when reviewing animal data, to ensure that the dose of atropine given

was sufficient to influence outcome. Another problem in extrapolating animal data to man is that

many animal models evaluate mortality up to 24 hours, after only one injection of an antidote or

antidotes given immediately following exposure to an organo phosphorus compound, a model

not likely to be mimicked in clinical practice. Given the importance of adequate supportive

therapy in the clinical setting, and particularly the importance of a patent airway, it is surprising

that many studies do not state whether such treatment was employed, even when large animals

such as buffalo calves.

Mutagenicity testing

Atropine caused non-specific aggregation of chromosomes, considered to be of no cytogenetic

danger Atropine sulphate was assessed as negative in the Ames assay, using one or more

Salmonella typhimurium standard strains (TA98, TA100, TA1535, TA1537 and TA1538).

8.3.2. Carcinogenicity testing

Atropine may promote experimental carcinogenesis in rat stomach caused by N-methyl-N’-nitro-

Nnitrosoguanidine. In a long-term trial of 858 rats by Schmahl and Habs, atropine was not found

to be carcinogenic.


34

8.3.3. Teratogenicity testing

Chick eggs were injected with 0.6 to 1.5mg atropine during the interval of 4 to 12 days

incubation. No defects were produced . Atropine given to rat dams from days 7 to 19 of gestation

resulted in avoidance learning deficits in their pups compared to controls. Findings suggested

that prenatal exposure to sympatholytic drugs may produce adverse effects on the behavioural

development of pups.

8.3.4. Behavioural toxicology

In microencephalic rats, compared to normal controls the magnitude of deficits in learning the

Morriswater maze increased as a function of atropine dose, suggesting that learning and memory

may berelated to changes in the number and/or function of muscarinic cholinergic receptors.

Behavioural alterations have been noted amongst the offspring of rats treated during pregnancy

with atropine.

Pharmacokinetics

Absorption

Oral absorption. Atropine is absorbed irregularly from the gastrointestinal tract, and more slowly

than with parenteral dosing. In adults, atropine is absorbed mainly from the duodenum and

jejunum rather than the stomach. Maximum radioactivity, using 3H-atropine, was found one

hour after an oral dose . Absorption of orally administered atropine may be delayed if atropine

has been previously administered, a 38% increase in small bowel transit time was observed

following intramuscular injection of atropine. In children, who received atropine 0.03mg/kg

orally, peak plasma concentrations occurred at 90 minutes with only 10-20% occupancy of

muscarine-2 subtype receptors. By contrast, after 0.02mg/kg intramuscular administration, peak

was at 25 minutes with 60-70% receptor occupancy. Following an oral dose of 0.03mg/kg

atropine, a mean maximum serum concentration of 6.7nmol/L occurred at two hours in children,

compared with 5.7 nmol/L at 30 minutes after intramuscular administration .

Rectal absorption. In children, rectal absorption of atropine is slower than absorption from the

Intramuscular route. Peak plasma concentrations of 0.7μg/L occurred after 15 minutes, following

rectal administration of atropine, compared with 2.4 μg/L, five minutes after intramuscular

dosing . Peak plasma concentrations after rectal dosing in children below 15kg in weight were

lower than in older children (but not to a clinically significant degree) and plasma concentrations

declined faster.


35

Sublingual absorption. Oral sublingual atropine absorption was considered to be "of minor

clinical significance" compared to absorption after intramuscular or subcutaneous administration.

Absorption from the sublingual route was variable and low in pregnant women at full term given

0.02mg/kg to 0.07mg/kg compared to intramuscular or subcutaneous administration of

0.02mg/kg . A 7-month child in a systole received a sublingual injection of atropine 0.15mg

(with adrenaline) with return of sinus rhythm and pulse .

Inhalation. Inhalation of atropine sulphate from a pressurized metered-dose inhaler resulted in

peak serum concentrations of 4.9 μg/L, 6.1 μg/L and 7.9 μg/L from administration of 1.7mg,

3.4mg and 5.2mg respectively. By comparison, a 1.67mg intramuscular injection of atropine free

base (equivalent to 2mg atropine sulphate) gave a mean peak concentration of 8.4 μg/L.

Ocular absorption. Some absorption of atropine can occur from the lower cul-de-sac of the eye

Peak plasma concentration was reached within 8 minutes after instillation of a 1% atropine

Atropine

Dermal absorption. Limited absorption occurs from the intact skin.

Intramuscular absorption. Intramuscular absorption of atropine and atropine sulphate depends

on the method of injection, the site of injection and the pharmaceutical form. Exercise may

increase the rate of absorption. Atropine and atropine sulphate reach peak plasma levels when

injected intramuscularly in about 30 minutes. In pregnant women at full term, however, mean

peak plasma levels were reached at 1.59 hours, following a dose of 0.01mg/kg . Absorption may

be faster if atropine is injected into the deltoid muscle rather than the gluteal or vastus lateralis

muscles. A study using time to peak heart rate to seek differences between routes of

administration and pharmaceutical forms, found that intravenous administration was most rapid.

subcutaneous absorption. There was no significant difference in the rate of absorption of doses

(0.02mg/kg atropine) given intramuscularly or subcutaneously to full term pregnant women.

Endotracheal absorption. Optimal drug doses and absorption parameters for administration by

the endotracheal route are unknown but medications should be administered at 2 to 2.5 times the

recommended intravenous dose, and diluted before use in 10ml saline or distilled water in

adults . In children with normal cardiac status, Howard & Bingham (1990) found that there was

no difference between effect on heart rate or speed of onset with either intravenous atropine

sulphate 0.025mg/kg dilute in 2ml saline, given at the same time as 2ml saline endotracheally or

twice the dose (ie 0.05mg/kg) of atropine given endotracheally at the same time as 2ml


36

intravenously. After studying 50 patients using dose titration with endotracheal atropine, it was

considered that if atropine must be given by the endotracheal route in an emergency, then

0.03mg/kg or more may be comparable to the effect of 0.01mg/kg given

intravenously. Any route of vascular administration was considered preferable to the

endotracheal route .

Intraosseous administration. Animal studies with atropine have shown similar actions and drug

concentrations after intraosseous administration to those after intravenous administration.

Establishment of an intraosseous route in children 6 years old or younger has been suggested, if

venous access cannot be achieved. Intraosseous administration has been used in older children &

adults, and has also been considered preferable to the endotracheal route.

Distribution

After intravenous dosing, atropine distributes rapidly with only 5% remaining in the blood

compartment after five minutes . Initial distribution half-life is approximately one minute .

Elimination kinetics can be fitted to a two-compartment model after therapeutic doses. The

apparent volume of distribution (Vd) is 1-1.7 L/kg with a clearance of 5.9-6.8 ml/kg/minute and

a half-life of 2.6-4.3 hours in the elimination phase Atropine rapidly crosses the placenta, with

apparent fetal uptake. No distribution into the amniotic fluid was found in one study but

significant distribution in another. In one study, concentrations in the umbilical vein were 93% of

the maternal level five minutes after an intravenous injection. Small quantities of atropine are

stated to appear in breast milk but there is little data to support this (atropine may also impair

milk production, although this is not conclusively documented

Penetration into human lumbar cerebrospinal fluid was less complete, particularly after a single

Intravenous injection. It has been speculated that the cerebrospinal fluid (CSF) represents a

"deep" compartment with slow drug penetration. Nonetheless, atropine penetration is assumed to

be greater into the central nervous system than into lumbar cerebrospinal fluid (CSF), compatible

with the well-known central anticholinergic effects of the drug. Penetration of atropine into the

eye after both local and systemic administration is slow and incomplete.

Elimination

After intravenous dosing, atropine elimination fits a two-compartment model with an intrinsic

clearance of 5.9-6.8 ml/kg/min and a plasma half-life of 2.6-4.3 hours in the elimination phase.


37

The elimination half-life of atropine is longer in children less than two years of age, and in the

elderly. In children, this is due to an increased volume of distribution (Vd), increasing the half-

life up to 5-10 hours in the neonate. In the elderly (70 years and older), the half-life may be

prolonged from 10 to 30 hours due to reduced clearance. These changes do not appear to be sex-

related. Not only the kinetics, but also the dynamics may change with age, making both the

younger and older patient more sensitive to a given dose. Patients with Down’s syndrome may

exhibit abnormally greater cardioaccelerator response to intravenously administered atropine

while patients with albinism may have decreased susceptibility to some of the actions of

atropine. The mechanisms for these differences are unclear. Atropine is metabolized in the liver

by microsomal monooxygenases. HPLC separation of urine has identified 5 compounds:

atropine, noratropine, tropine, atropine-N-oxide(equatorial isomer), and tropic acid . Thus,

atropine is partly metabolized and partly excreted unchanged in the urine, the unchanged portion

being approximately 50% (Since biliary excretion is negligible, the hepatic plasma clearance of

519±147 ml/min represents metabolism. Hepatic blood clearance and extraction ratio were

476±136 ml/min and 0.32, respectively. The elimination of atropine is, therefore, partly flow-

dependent (Hinderling et al., 1985). Following an intravenous injection, 57% of the dose is found

in the urine as unchanged atropine and 29% as tropine. Since the renal plasma clearance

(656±118 ml/min) was found to approach the renal plasma flow (712±38 ml/min), tubular

excretion may occur. Thus, both liver and renal disease can be expected to influence the kinetics

of atropine.

Dose and duration of atropine sulphate therapy

The optimal dose of atropine sulphate required to manage moderate and severe organophosphate

poisoning is controversial. Recommendations for initial intravenous dosing range from 1 mg in

adults and 0.01 mg/kg in children as a "test dose" up to 5 mg in adults, and 0.05 mg/kg in

children. Larger doses may, however, be necessary: in a retrospective study of 37 paediatric

patients, Zweiner & Ginsburg (1988) found that one third of patients required at least 0.05 mg/kg

before any decrease in cholinergic activity was observed. In one adult, up to 15 mg was given as

a single bolus most cases of mild-moderate organophosphate poisoning require no more than a

total of 5-50 mg atropine. A small number of patients appear to have required massive quantities

of atropine, sometimes for prolonged periods, in particular those poisoned with highly lipid-

soluble compounds, such as fenthion Total doses of atropine as high as 3911 mg 11 443 mg


38

and 19 590 mg have been given to patients, who recovered from their severe poisoning. 5 weeks

Relapse during therapy also appears to be more common with highly lipophilic

organophosphates. Because of the risk of relapse, patients should be weaned off atropine slowly.

If large quantities of atropine sulphate are given, care should be taken to avoid using

formulations containing preservatives such as chlorbutanol or benzyl alcohol.

Route of administration

In order to cater for the sometimes large doses of atropine required to treat organophosphate

poisoning some manufacturers produce larger ampoules, containing 10-100 mg of atropine. It

may be more practicable to administer large doses by intravenous infusion rather than by

Intermittent bolus injections. Intravenous infusion may save time, produce less fluctuation in

plasma atropine concentrations and make weaning much easier. On the other hand, because

administration by infusionmay result in less frequent assessments, it is much easier for a patient

to develop atropine toxicity while on an infusion than when receiving bolus injections.

Moreover, it should be remembered that the halflife of atropine (up to 4 hours or longer in

children and the elderly) necessitates using a bolus dose as well as adjusting the drip rate if a

rapid increase in the degree of atropinization is required. In an emergency situation, it may be

necessary to give atropine before intravenous or intraosseous access can be established. The

endotracheal route has therefore been used, when vascular access was not available. Atropine

was given endotracheally to a 16-month-old child with a carbamate overdose The child

responded rapidly to 1.0mg, and a total of 2.5 mg atropine was given by this route. The optimal

dose requirements for the endotracheal route have not yet been established, however. Oral

administration of atropine has been reported as being useful for stable patients on intravenous

therapy for several days or weeks, which need slow weaning. Atropine given intramuscularly in

some specialized injectors may have faster onset of action than other forms of intramuscular

injection. The recommended dose for nerve agent exposure in adult, otherwise healthy patients

with mild to moderate symptoms is 2 to 4 mg.

Initial doses of both atropine and atropine sulphate administered to adults and children by the

intramuscular route appear to be similar to those given intravenously, although onset of action

will be slower after intramuscular injection.


39

Adverse effects of atropine therapy

Atropine toxicity was noted on at least one occasion in 16 of 61 patients (26%) in a retrospective,

multicentre study noted over-atropinization in three of 232 cases. The dose of atropine should be

reduced if the patient shows signs of atropine toxicity such as fever, or delirium If atropine is

administered to hypoxic patients there is a risk of ventricular tachycardia or fibrillation. In this

situation, atropine should be given at the same time as the patient is oxygenated. Prolonged

atropinization may cause paralytic ileus. Paralytic ileus was also reported in an infant with

Down’s syndrome who was being treated with topical atropine. In a case reported, rigidity was

observed for up to 10 days following weaning after a five-week period of therapy. Mydriasis, but

no other pharmacological effects, was noted in a neonate, whose mother had been given atropine

for organophosphate poisoning before the birth. Other adverse effects of atropine, not necessarily

associated with treatment of organophosphorus insecticide poisoning, include precipitation of

glaucoma and hypersensitivity

reactions (anaphylaxis).

Clinical atropine toxicity

Poisoning can occur following oral, ocular, respiratory or parenteral exposure. There are

numerous case reports of atropine poisoning from plants from antiquity through to the present. In

a case of jimsonweed poisoning (Datura stramonium), a four-year-old boy presented with

confusion, hallucinations, ataxia, and tachycardia. Symptoms developed three hours after

ingestion, recovery took two days. In a 65-year-old man, 3 mg of atropine from Atropa

belladonna leaves mistaken for burdock (Arctium lappa) leaves, produced not only peripheral

atropinization but also a central anticholinergic syndrome with restlessness, hyperactivity, and

dysphasia. Symptoms resolved within 24 hours with symptomatic therapy.

Mild atropine toxicity, with a central anticholinergic syndrome, may also occur after "normal"

dosing, as the prolonged half-life of atropine with increasing age puts the older patient at risk.

Reported three children overdosed with atropine following a thousand-fold error in dosage.

During the first 12 hours, the children were sedated and disoriented. They became increasingly

restless as a central anticholinergic syndrome persisted for two days, requiring large quantities of

diazepam for sedation; the pupils remained dilated for a week. In a review of nine cases of

accidental poisoning with oral drops, reported toxicity with atropine dosages ranging from 0.39-

3.55 mg/kg. One patient, a 6-week-old boy, presented with fever, irritability, warm dry skin,


40

inspiratory stridor, cyanosis of the hands and feet, and dilated and unresponsive pupils. Recovery

was uneventful. Following an accidental oral overdose of 0.3 mg/kg atropine in two small

children, reported maximum serum levels of 29 and 15.6 mg/L at 2 to 2.5 hours, concentrations

normally found in the distribution phase following an intravenous bolus of a therapeutic dose.

Symptoms of toxicity resolved uneventfully within eight hours. In three-year old children, deaths

have been reported following ocular applications as low as 1.6 and 2 mg and oral doses of 100

mg, although one patient recovered following an estimated ingestion of 1 g.

Drug interactions

Intramuscular atropine may slow small bowel transit time by approximately 38%, which in turn

determines enterohepatic cycling frequency. Gastric emptying may also be delayed by atropine.

Thus, the pharmacokinetics and/or efficacy of oral drugs co administered with atropine may be

changed, as may the response of drugs that undergo enterohepatic circulation. Changes in drug

efficacy have occurred with levodopa (decreased effect) and (hallucinations) when

anticholinergics were given concomitantly. Pre-treatment with the calcium channel blocker,

verapamil has increased the tachycardia produced by atropine in healthy volunteers. Other drugs

with anticholinergic effects, such as tricyclic antidepressants, some antihistamines,

phenothiazines, disopyramide and quinidine, will have additive peripheral and central nervous

system anticholinergic activity if given with atropine (Dollery, 1991). Tertiary amine muscarinic

receptor Atropine antagonists used as antispasmodics, such as dicyclomine, oxyphencyclimine,

flavoxate and oxybutynin will also act similarly, as will quaternary ammonium muscarinic

receptor antagonists, for example, ipratropium, methscopolamine and homatropine.

The muscarinic actions of parasympathomimetic drugs such as carbachol, bethanecol and

pilocarpineare blocked by atropine. The action of anticholinesterase agents such as

physostigmine, neostigmine, edrophonium, ambenonium and pyridostigmine can be antagonised

at muscarinic receptor sites by atropine and vice versa, according to dose size.


41

PARACETAMOL:-

Paracetamol or acetaminophen is a widely used over-the-counter analgesic (pain reliever)

and antipyretic (fever reducer). It is commonly used for the relief of headaches and other minor

aches and pains and is a major ingredient in numerous cold and flu remedies. In combination

with opioid analgesics, paracetamol can also be used in the management of more severe pain

such as post surgical pain and providing palliative care in advanced cancer patients. The onset of

analgesia is approximately 11 minutes after oral administration of paracetamol, and its half-life is

1–4 hours.

While generally safe for use at recommended doses (1,000 mg per single dose and up to 3,000

mg per day for adults), acute overdoses of paracetamol can cause potentially fatal liver

damage and, in rare individuals, a normal dose can do the same; the risk is heightened byalcohol

consumption. Paracetamol toxicity is the foremost cause of acute liver failure in the Western

world, and accounts for most drug overdoses in the United States, the United Kingdom, Australia

and New Zealand.

It is the active metabolite of phenacetin, once popular as an analgesic and antipyretic in its own

right, but unlike phenacetin and its combinations, paracetamol is not considered carcinogenic at

therapeutic doses. The words acetaminophen (used in the United States, Canada, Japan, South

Korea, Hong Kong, and Iran) and paracetamol (used elsewhere) both come from a chemical

name for the compound: para-acetylaminophenol and para-acetylaminophenol. In some

contexts, it is simply abbreviated as APAP, foracetyl-para-aminophenol.

Synonyms:-

4-Hydroxyanilid kyseliny octove;

Abensanil; Acamol;

Acetagesic; Acetalgin;

Acetaminofen; Acetaminophen;

Algotropyl; Alvedon; Amadil;

Anaflon; Anelix; Apamid;

Apamide; APAP; Ben-u-ron;

Bickie-mol; Calpol; Cetadol;

Clixodyne; Datril;


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Dial-a-gesic; Dirox;

Dymadon; Eneril; Excedrin;

Febrilix; Febro-gesic;

Febrolin; Fendon; Finimal;

Hedex; Homoolan; Lestemp;

Liquagesic; Lonarid; Lyteca;

Lyteca syrup; Multin; NAPA;

Napafen; Napap; Naprinol;

NCI-C55801; Nobedon; Pacemo;

Panadol; Panets;

Paracetamole; Paracetamolo;

Parmol; Pedric; Phendon;

Pyrinazine; SK-Apap;

Tabalgin; Tapar; Temlo;

Tempanal; Tempra; Tralgon;

Tussapap; Tylenol; Valadol;

Valgesic

Chemical and physical properties of the pure substance

(a) Description: White crystalline powder

(b) Melting-point: 170°C

(c) Density: 1.293 g/cm3 at 21°C

(d) Solubility: Insoluble in water; very soluble in ethanol

(e) Octanol/water partition coefficient (P): log P, 0.31

(f) Conversion factor: mg/m3= 6.18 × ppm

Production and use

Paracetamol is used as an analgesic and antipyretic, in the treatment of a wide variety of arthritic

and rheumatic conditions involving musculoskeletal pain and in other painful disorders such as

headache, dysmenorrhoea, myalgia and neuralgia. It is also indicated as an analgesic and

antipyretic in diseases accompanied by generalized discomfort or fever, such as the common


43

cold and other viral infections. Other uses include the manufacture of azo dyes and photographic

chemicals, as an intermediate for pharmaceuticals and as a stabilizer for hydrogen peroxide.

The conventional oral dose of paracetamol for adults is 325–1000 mg (650 mg rectally); the total

daily dose should not exceed 4000 mg. For children, the single dose is 40–480 mg, depending on

age and weight; no more than five doses should be administered within 24 h. For infants under

three months of age, a dose of 10 mg/kg by is recommended.

Acetaminophen Pharmacokinetics

Absorption

Bioavailability

Well absorbed following oral administration, with peak plasma concentration attained within 10–

60 minutes (immediate-release preparations) or 60–120 minutes (extended-release preparations).

Poor or variable absorption following rectal administration; considerable variation in peak

plasma concentrations attained; time to reach peak plasma concentration is substantially longer

than after oral administration

Distribution

Extent

Rapidly distributed to most body tissues.Crosses placenta and is distributed into breast milk.

Plasma Protein Binding

25%.

Metabolism

Metabolized principally by sulfate and glucuronide conjugation; small amounts (5–10%)

oxidized by CYP-dependent pathways (mainly CYP2E1 and CYP3A4) to a toxic metabolite, N-

acetyl-p-benzoquinoneimine (NAPQI). NAPQI is detoxified by glutathione and eliminated; any

remaining toxic metabolite may bind to hepatocytes and cause cellular necrosis.

Elimination Route

Mainly excreted in urine as conjugates.


44

Half-life

1.25–3 hours

Storage

Oral

Tablets

Room temperature. Protect orally disintegrating tablets (Tylenol Meltaways) from high

humidity.Protect grape-flavored orally disintegrating tablets from light.

Suspension/Solution

Actions

Exhibits analgesic and antipyretic activity.

Weak, reversible, isoform-nonspecific cyclooxygenase inhibitor at dosages of 1 g

daily.Inhibitory effect on cyclooxygenase-1 is limited; does not inhibit platelet function

Uses for Acetaminophen

Pain

Symptomatic relief of mild to moderate pain.

Self-medication in children ≥6 years of age and adults for the temporary relief of minor aches

and pain associated with headache, muscular aches, backache, minor arthritis pain, common

cold, toothache, and menstrual cramps. Self-medication in infants and children for the temporary

relief of minor aches and pain associated with the common cold, flu, headache, sore throat,

immunizations, toothache, muscle aches, sprains, and overexertion.

Self-medication in fixed combination with aspirin and caffeine for the temporary relief of mild to

moderate pain associated with migraine headache. This combination also can be used for the

treatment of severe migraine headache if previous attacks have responded to similar nonopiate

analgesics or NSAIAs.


45

Symptomatic treatment of pain associated with osteoarthritis; considered an initial drug of choice

for pain management in osteoarthritis patients.

Used in fixed combination with isometheptene and dichloralphenazone for symptomatic relief of

tension and vascular headaches.

Used in fixed combination with other agents (e.g., chlorpheniramine, dextromethorphan,

diphenhydramine, doxylamine, guaifenesin, phenylephrine, pseudoephedrine) for short-term

relief of minor aches and pain, headache, fever, and/or other symptoms (e.g., rhinorrhea,

sneezing, lacrimation, itching eyes, oronasopharyngeal itching, nasal congestion, cough)

associated with seasonal allergic rhinitis (e.g., hay fever), other upper respiratory allergies, or the

common cold.

Fever

Self-medication to reduce fever in infants, children, and adults.

Administration

Usually administered orally; may be administered rectally as suppositories in patients who

cannot tolerate oral therapy.

Oral Administration

Swallow extended-release tablets whole; do not crush, chew, or dissolve in liquid.

Place orally disintegrating, fixed-combination acetaminophen/caffeine tablets on the tongue to

dissolve; swallow with saliva. For best taste, do not chew.

Because combinations and dosage strengths vary for fixed-combination preparations, consult

manufacturer’s product labeling for appropriate dosage of the specific preparation.

Pediatric Administration

Acetaminophen oral drops generally used in infants 0–23 months of age. Use the calibrated

dosing device provided by the manufacturer for measurement of the dose.


46

Oral suspension may be used in children ≥4 months age.Use the calibrated dosage cup provided

by the manufacturer for measurement of the dose.

80-mg chewable tablets or orally disintegrating tablets may be used in children ≥2 years of age.

160-mg chewable tablets or orally disintegrating tablets or 325-mg conventional tablets

commonly used in children ≥6 years of age.

Orally disintegrating tablets (Tylenol Meltaways) should be allowed to dissolve in the mouth or

should be chewed before swallowing. Use caution to ensure that the correct number of tablets

required for the intended dose is removed from the blister package.

Rectal Administration

Dividing suppositories in an attempt to administer lower dosages may not provide a predictable

dose.

Some experts state that rectal acetaminophen preparations should not be used for self-

medication in children unless such use is specifically discussed with a clinician and parents or

caregivers are instructed to adhere to dosage and administration recommendations.

Pediatric Patients

Dosage in children should be guided by body weight. (See Pediatric Use under Cautions.)

Pain

Oral

Dose may be given every 4–6 hours as necessary (up to 5 times in 24 hours)


47

PLAN OF WORK:-

1. Collection of cow ghee from appropriate source.

2. Evaluation of cow ghee by some selected parameters.

3. Evaluation of cow ghee

Organoleptic properties :-

Color

Odor

Taste

Texture

Physical parameter :-

Moisture: - Moisture refers to the presence of a liquid, especially water, often in trace amounts.

Small amounts of water may be found, for example in foods, and in various commercial

products. The moisture contained in a material comprises all those substances which vaporize on

heating and lead to weight loss of the sample. The weight is determined by a balance and

interpreted as the moisture content. According to this definition, moisture content includes not

only water but also other mass losses such as evaporating organic solvents, alcohols, greases,

oils, aromatic components, as well as d Methods of moisture content determination. The

moisture content influences the physical properties of a substance such as weight, density,

viscosity, refractive index, electrical conductivity and many more.

Over the years, a wide range of methods has been developed to measure these physical quantities

and express them in the form of the moisture content.

The measurement methods can logically be divided in the following procedures:

– Thermo- gravimetric


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– Chemical

– Spectroscopic

– Others, decomposition and combustion products.

Drying oven

Principle: - A sample is dried by means of hot circulating air. To tighten up the drying conditions

or to protect thermally unstable substances, drying is frequently performed under vacuum. The

moisture content is determined by a differential weighing before and after drying. Importance

For many substances the drying oven method is a mandatory reference method with good

reproducibility. This method is frequently cited in laws governing food.

Advantage the advantage of the classical drying oven method lies in the number of samples

which can be investigated simultaneously. Moreover, it offers the possibility of analyzing large

amounts of samples, which can be a particular advantage with in homogeneous samples.

Principles

These methods rely on measuring the mass of water in a known mass of sample. The

moisture content is determined by measuring the mass of a food before and after the water is

removed by evaporation:

Ere, MINITIAL and MDRIED are the mass of the sample before and after drying, respectively. The

basic principle of this technique is that water has a lower boiling point than the other major

components within foods, e.g., lipids, proteins, carbohydrates and minerals. Sometimes a related

parameter, known as the total solids, is reported as a measure of the moisture content. The total

solids content is a measure of the amount of material remaining after all the water has been

evaporated:


49

PH :- pH is a measure of the acidity or basicity of an aqueous solution Solutions with a pH less

than 7 are said to be acidic and solutions with a pH greater than 7 are basic or alkaline. n a

solution pH approximates but is not equal to p[H], the negative logarithm (base 10) of the molar

concentration of dissolved hydronium ions (H3O+); a low pH indicates a high concentration of

hydronium ions, while a high pH indicates a low concentration. This negative of the logarithm

matches the number of places behind the decimal point, so, for example, 0.1 molar hydrochloric

acid should be near pH 1 and 0.0001 molar HCl should be near pH 4 (the base 10 logarithms of

0.1 and 0.0001 being −1, and −4, respectively). The measurement of pH in an aqueous solution

can be made in a variety of ways. The most common way involves the use of a pH sensitive glass

electrode, a reference electrode and a pH meter. A pH meter is always recommended for precise

and continuous measuring. Most laboratories use a pH meter connected to a strip chart recorder

or some other data acquisition device so that the reading can be recorded or stored electronically

over a user-defined time range. Mathematical definition pH is defined as a negative

decimal logarithm of the hydrogen ion activity in a solution.

Where aH+ is the activity of hydrogen ions in units of mol/L (molar concentration). Activity has

a sense of concentration; however activity is always less than the concentration and is defined as

a concentration (mol/L) of an ion multiplied by activity coefficient. The activity coefficient for

diluted solutions is a real number between 0 and 1 (for concentrated solutions may be greater

than 1) and it depends on many parameters of a solution, such as nature of ion, ion force,

temperature, etc. For a strong electrolyte, activity of an ion approaches its concentration in

diluted solutions. Activity can be measured experimentally by means of an ion-selective

electrode that responds, according to the Nernst equation, to hydrogen ion activity. pH is

commonly measured by means of a glass electrode connected to a milli-voltmeter with very high

input impedance, which measures the potential difference, or electromotive, E, between an

electrode sensitive to the hydrogen ion activity and a reference electrode, such as a calomel

electrode or a silver chloride electrode. Quite often, glass electrode is combined with the


http://en.wikipedia.org/wiki/Silver_chloride_electrode

http://en.wikipedia.org/wiki/Saturated_calomel_electrode

http://en.wikipedia.org/wiki/Saturated_calomel_electrode

http://en.wikipedia.org/wiki/Glass_electrode

http://en.wikipedia.org/wiki/Nernst_equation

http://en.wikipedia.org/wiki/Hydrogen_ion

http://en.wikipedia.org/wiki/Activity_(chemistry)

http://en.wikipedia.org/wiki/Hydrogen_ion

http://en.wikipedia.org/wiki/Logarithm

http://en.wikipedia.org/wiki/Hydrochloric_acid

http://en.wikipedia.org/wiki/Hydrochloric_acid

http://en.wikipedia.org/wiki/Molar_(concentration)

http://en.wikipedia.org/wiki/Hydronium_ion

http://en.wikipedia.org/wiki/Molar_concentration

http://en.wikipedia.org/wiki/Molar_concentration

http://en.wikipedia.org/wiki/Logarithm

http://en.wikipedia.org/wiki/Alkaline

http://en.wikipedia.org/wiki/Base_(chemistry)

http://en.wikipedia.org/wiki/Acidic

http://en.wikipedia.org/wiki/Aqueous_solution

http://en.wikipedia.org/wiki/Base_(chemistry)

http://en.wikipedia.org/wiki/Acid

50

reference electrode and a temperature sensor in one body. The glass electrode can be described

(to 95–99.9% accuracy) by the Nernst equation:

Where E is a measured potential, E0 is the standard electrode potential, that is, the electrode

potential for the standard state in which the activity is one. R is the gas constant, T is the

temperature in Kelvin’s, F is the Faraday constant, and n is the number of electrons transferred

(ion charge), one in this instance. The electrode potential, E, is proportional to the logarithm of

the hydrogen ion activity.

This definition, by itself, is wholly impractical, because the hydrogen ion activity is the product

of the concentration and an activity coefficient. To get proper results, the electrode must

be calibrated using standard solutions of known activity.

The operational definition of pH is officially defined by International Standard ISO 31-8 as

follows: For a solution X, first measures the electromotive force EX of the galvanic cell

Reference electrode|concentrated solution of KCl || solution X|H2|Pt

and then also measure the electromotive force ES of a galvanic cell that differs from the above

one only by the replacement of the solution X of unknown pH, pH(X), by a solution S of a

known standard pH, pH(S). The pH of X is then

The difference between the pH of solution X and the pH of the standard solution depends only

on the difference between two measured potentials. Thus, pH is obtained from a potential

measured with an electrode calibrated against one or more pH standards; a pH meter setting is

adjusted such that the meter reading for a solution of a standard is equal to the value pH(S).

Values pH(S) for a range of standard solutions S, along with further details, are given in

the IUPAC recommendations. The standard solutions are often described as standard buffer

solution. In practice, it is better to use two or more standard buffers to allow for small deviations

from Nernst-law ideality in real electrodes. Note that, because the temperature occurs in the

defining equations, the pH of a solution is temperature-dependent.


http://en.wikipedia.org/wiki/IUPAC

http://en.wikipedia.org/wiki/PH_meter

http://en.wikipedia.org/wiki/Galvanic_cell

http://en.wikipedia.org/wiki/ISO_31-8

http://en.wikipedia.org/wiki/Operational_definition

http://en.wikipedia.org/wiki/Calibrate

http://en.wikipedia.org/wiki/Activity_coefficient

http://en.wikipedia.org/wiki/Concentration

http://en.wikipedia.org/wiki/Faraday_constant

http://en.wikipedia.org/wiki/Kelvin

http://en.wikipedia.org/wiki/Gas_constant

51

Measurement of extremely low pH values, such as some very acidic mine waters, requires

special procedures. Calibration of the electrode in such cases can be done with standard solutions

of concentrated sulfuric acid, whose pH values can be calculated with using Pitzer parameters to

calculate activity coefficients.

PH is an example of an acidity function. Hydrogen ion concentrations can be measured in non-

aqueous solvents, but this leads, in effect, to a different acidity function, because the standard

state for a non-aqueous solvent is different from the standard state for water. Super acids are a

class of non-aqueous acids for which the Hammett acidity function, H0, has been developed.

PH in its usual meaning is a measure of acidity of (dilute) aqueous solutions only. Recently the

concept of "Unified pH scale" has been developed on the basis of the absolute chemical potential

of the proton. This concept proposes the "Unified pH" as a measure of acidity that is applicable

to any medium: liquids, gases and even solids.

Particle size:-

Particlesize isa notion introducedforcomparing dimensions of solid particles(flecks), liquid partic

les (droplets), or gaseous particles (bubbles). Optical counting methods PSDs can be measured

microscopically by sizing against a graticule and counting, but for a statistically valid analysis,

millions of particles must be measured. This is impossibly arduous when done manually, but

automated analysis of electron micrographs is now commercially available. The need for particle

size control in the manufacture of pharmaceuticals is becoming increasingly apparent as the

pharmaceutical industry attempts to capitalize on some APIs with less-than-ideal solubility

profiles. Also, significant advances in drug delivery have been made in which a finely divided

API, with the concomitant increase in specific surface area, has resulted in increased

bioavailability. Precise particle size control technologies have also assisted in the development of

drug delivery platforms for the delivery of a medicament.

Viscosity: - Viscosity is a measure of the resistance of a fluid which is being

deformed by either shear or tensile stress. Viscosity is measured with various types of

viscometers and rheometers. A rheometer is used for those fluids which cannot be

defined by a single value of viscosity and therefore require more parameters to be set


http://en.wikipedia.org/wiki/Rheometer

http://en.wikipedia.org/wiki/Viscometer

http://en.wikipedia.org/wiki/Tensile_stress

http://en.wikipedia.org/wiki/Shear

http://en.wikipedia.org/wiki/Fluid

http://en.wikipedia.org/wiki/Drag_(physics)

http://en.wikipedia.org/wiki/Electron_microscope

http://en.wikipedia.org/wiki/Gas

http://en.wikipedia.org/wiki/Liquid

http://en.wikipedia.org/wiki/Solid

http://en.wikipedia.org/wiki/Dimension

http://en.wiktionary.org/wiki/Notion

http://en.wikipedia.org/wiki/Hammett_acidity_function

http://en.wikipedia.org/wiki/Superacid

http://en.wikipedia.org/wiki/Acidity_function

http://en.wikipedia.org/wiki/Pitzer_parameter

52

and measured than is the case for a viscometer. Close temperature control of the fluid

is essential to accurate measurements, particularly in materials like lubricants, whose

viscosity can double with a change of only 5 °C. delta p = difference in density

between the sphere and the liquid

g = acceleration of gravity

a = radius of sphere

v = velocity = d/t = (distance sphere falls)/(time of it takes to fall)

A viscometer (also called viscosimeter) is an instrument used to measure the viscosity of a fluid.

For liquids with viscosities which vary with flow conditions, an instrument called a rheometer is

used. Viscometers only measure less than one flow condition.

Copper content

• Chemical parameter

Acid value acid value (or "neutralization number" or "acid number" or "acidity") is the mass of potassium hydroxide (KOH)

in milligramsthat is required to neutralize one gram of chemical substance. The acid number is a measure of the amount of carboxylic

acid groups in a chemical compound, such as a fatty acid, or in a mixture of compounds. In a typical procedure, a known amount of sample

dissolved in organic solvent (often isopropanol), is titrated with a solution of potassium hydroxide with known concentration and

with phenolphthalein as a color indicator.

The acid number is used to quantify the amount of acid present, for example in a sample of biodiesel. It is the quantity of base, expressed in

milligrams of potassium hydroxide, that is required to neutralize the acidic constituents in 1 g of sample.

Veq is the amount of titrant (ml) consumed by the crude oil sample and 1ml spiking solution at the equivalent point, beq is the amount of

titrant (ml) consumed by 1 ml spiking solution at the equivalent point, and 56.1 is the molecular weight of KOH. WOil is the weight of the

sample in grams.


http://en.wikipedia.org/wiki/KOH

http://en.wikipedia.org/w/index.php?title=Spiking_solution&action=edit&redlink=1

http://en.wikipedia.org/wiki/Titration

http://en.wikipedia.org/wiki/Biodiesel

http://en.wikipedia.org/wiki/Phenolphthalein

http://en.wikipedia.org/wiki/Concentration

http://en.wikipedia.org/wiki/Titration

http://en.wikipedia.org/wiki/Isopropyl_alcohol

http://en.wikipedia.org/wiki/Fatty_acid

http://en.wikipedia.org/wiki/Carboxylic_acid

http://en.wikipedia.org/wiki/Carboxylic_acid

http://en.wikipedia.org/wiki/Chemical_substance

http://en.wikipedia.org/wiki/Milligrams

http://en.wikipedia.org/wiki/Potassium_hydroxide

http://en.wikipedia.org/wiki/Rheometer

http://en.wikipedia.org/wiki/Flow_conditioning

http://en.wikipedia.org/wiki/Fluid

http://en.wikipedia.org/wiki/Viscosity

53

The molarity concentration of titrant (N) is calculated as such:

In which WKHP is the amount (g) of KHP in 50 ml of KHP standard solution, Veq is the amount of titrant (ml) consumed by 50 ml

KHP standard solution at the equivalent point, and 204.23 is the molecular weight of KHP.

Saponification value

Iodine value

R M value

P value

• Formulate the ophthalmic gel (drug) with ghee by appropriate method.


http://en.wikipedia.org/wiki/KHP

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