Development of ophthalmic products

ophthalmic

The ophthalmic are sterile dosage forms to be administered on to the surface of the eye for the local effect

Ideal characters of ophthalmic dosage forms

They should be free from foreign particles They should be sterile Ph of the preparation should not cause any

irritation to the eye The preparation should be isotonic with

lachyhrimal fluids The viscosity of the ophthalmic should be

proper enough as to prolong the contact of the drug with eye

Ophthalmic solutions

Ophthalmic solutions are sterile solution of drugs meant to be instilled to the eye cavity

They are of 2 types

a) eye drops

b)eye lotions

Eye drops Eye drops are aqueous are oily solutions administered in the

form of the drops in to the conjunctiva sac Ex-physiostygmine eye drops,phenylephrine eye drops. Formulation: Requirements: Stabilizers: Antioxidants Buffers Chelating agents Preservatives Thickening agents(viscosifiers) Tonicity agents Vehicles

Stabilizers

Antioxidants :they prevent the oxidation during the storage conditions to keep them stable

Ex-sodium thiosulphate ,sodium meta bisulphate

Buffers:they maintain the ph of the solution at the desired point with out any change

normally buffers of low ph are used They also maintain the chemical stability of the

drug ex-boric acid ,sodium citrate buffer

Chelating agents

Chelating agents complexes with metals and prevent their catalyting activity upon the oxidation

They also improve the preservative activity Ex-benzykonium chloride EDTA

Preservatives

These are the chemical substances are used which have the property to prevent the spoilage of the preparation due to the microbial growth

Characteristics of the ideal preservative It should be nonirritating to the eye membrane it

should be stable thought the shelf life of the product

It should have broad spectrum of activity

Ex-chloral butanol,benzylkonum chloride

Thickening agents (viscosifying agents)

Thickening prolong the contact time between the drug and the eye,their by increasing the therapeutic action

Ex-hydroxy propylmethyl cellulose,povidine Requirements of a viscosifier It should give a clear solution The solution of the viscosfier should be easily

filterable It should not alter the activity of the drugs

Tonicity agents The agents make the solution isotonic with lachrymal fluid Tonicity of the solutions depend upon the nature and amount of

solutes present Ex- dextrose,Nacl Vehile The vehicle serves as the medium for the preparation of

formulation The ph of the vehicle should be adjusted to retain the maximum

stability of the drug and therapeutic activity It should be fungicidal or bactericidal in nature ex-boric acid vehicle (ph-4.7) isotonic phosphate

Eye lotions

Eye lotions are aqueous solutions meant to be instilled in to the eye cavity for cleaning purpose

The eye lotions are supplied in the concentrated form and required to be diluted with warm water immediately before use

They are require to prepare fresh and should not be stored more than 2 days as the lotion may get contaminated with micro organisms ex-Nacl,NaHCo3 eye lotions

Eye suspensions

The eye suspensions prepared only those cases when the drug is insoluble in the desired vehicle

They are also used to produce sustain action of the preparation

Essential characteristics of eye suspension They should be sterile They should have desired viscosity They should be isotonic They should be shaken thoroughly before use in

order to distribute the drug particle uniformly

formulation

Buffers ex:boric acid Preservatives ex:chloro butanal Suspending agents At low concentrations polymers acts as the

protective colloids and suspend the insoluble solids in vehicle for long time

At high concentrations they decrease rate of setting of the suspended of particles and there by improve the physical stability

Ex-methyl cellulose,hydroxy propyl methyl cellulose

wetting agents They reduce the interfacial tension between solid

particles and liquid medium They displace the air from the surface of the

hydrophobic substances and permit water to surround the particles

Surfactants with hlb value between 7&9 acts as the destining agents

They are used in the low concentration of 0.05-5% Ex- polysorbate ,polyoxy ethylebe dervatives

they prevent the formation of hard sediments of the solids and provide easy radioperson of any settled particles ex hydrophilic polymers

Vehicle Purified water used as a vehicle

Flocculating agents

eye ointments

They are sterile preparations meant for application to eye The ophthalmic ointments are semi solid dosage forms These are prepared under the aseptic conditions Formulation Bases: It is anhydrous and incorporates an oleo genus base and mineral

oil which in the proportion to obtain the desired consistency and melting temperature

Composition of most commonly used base is Yellow soft paraffin-80 parts Liquid paraffin-10 parts Wool fat-10 parts

Antioxidants :bht(butylated hydroxy toulene)toccoferal

Buffers:sodium acetate,sodium citrate Surfacantants :they are used to soluabilize

the drug in the base for ex-polyethylene glycol,poly oxyl 140 sterate

Preservative Ex-methyl paraben(0.1-0.2%) proyl

paraben(0.04%)

Ophthalmic emulsions

Formulation Non aqueous vehicle The drug is dissolved in the non aqueous vehicle ex-

caster oil,arachis oil Emulsifying agents Generally non-ionic surfactants

(polysorbates,polyethylene glycol derivatives of sorbitol esters ) are used ex-span-20,span-80,tween-20,tween-80

emulsion stabilizers

They improve the stability of the emulsion produced by the emulsifying agents

Ex-methylcellulose, sodium carboxy methyl cellulose

Preservatives Ex -Bezylkonium chloride,chloro butanol Antioxidants Ex-sodium thiosulphate, sodium meta

bisulphate

opthalmic gells

Formulation : Gelling agents:they absorb the water and

sweell to give a gel like consistency ex:hpmc,carbomer

Preservatives:benzylkonium chloride(0.02%)\ Vehile:purified water

manufacturing considerations of ophthalmic products

Requirements of sterile manufacturing personal require ments Environmental control and its evaluation traffic control Cleaning of equipments and sterilization

Personal requirements

The uniform of the employees should be sterile and made of dacron(effective barriers discharged particles

They should also wear head covers ,shoe covers,face masks while working the aseptic room

Ex:if any worker is suffer from cold he must report it to the higher authority and should be restricted from entering to the aseptic area

environmental control and its evaluation

The environmental control maintained is different for different areas(compounding area,filling ,packing areas)

Stringent environmental controlled is required before and during the process of the prenatal

Two types of environmental control can be maintained depending on the exposure and the type of process

class 10000 It implies that area contains not less than 10000 particles of

0.5micrometer and even larger per cubic feet of air They class can be achieved by the air condition

Class 100It implies that area contains the not less than 100 particles of 0.5

micrometers larger per cubic feet of airThese class can be achieved by laminar air flow

Traffic control

The traffic include the supply of the material and entry &exit of the workers in the production area

The traffic should be strictly controlled in aseptic rooms

They should change their clothes cover the faces with masks wear hand gloves and head covers and shoes

Cleaning of equipments

These done to facilitate easy thorough cleaning of the internal structures such as joints ,crevices ,screw threads

An effective detergent and stiff brush should be used for cleaning purpose

Sterilization Non sterile preparations can cause cornial ulcers and blindness The most common contaminant of ophthalmic belong to the

staphylococcus species Sterilization required to remove all forms of micro organisms No preservative can destroy the viruses

sterilization can be achieved through

Filtration Gaseous sterilization Moist heat sterilization Radiation sterilization

references

Cooper and guns Rm meheta www.ophthalmic.hyperguides.com

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