EYE DROP

EYE DROP

Definition

Eye drops are sterile aqueous or oily solutions or suspensions for instillation in the eye. They are applied into the cul-de-sac (i.e. the space between the eye ball and eye lid).

Essential characteristics

(i)                   They should be sterile.

(ii)                 They should be iso-osmotic with lachrymal secretions; i.e. the eye drops are iso-osmotic with 0.9%w/v sodium chloride solution.

(iii)                They should have almost neutral pH (pH 7.4).

(iv)               They should be free from foreign particles, fibres and filaments.

(v)                 They should be preserved with a suitable bactericide.

(vi)               They should remain stable during its storage.

 

Ingredients

(i) Vehicle:                             Purified water

(ii) Antimicrobial agents or preservatives:     

(a)     Phenylmercuric acetate (PMA)                 –              0.002%w/v

(b)     Phenylmercuric nitrate (PMN) –              0.002%w/v

(c)     Benzalkonium chloride (BAC) –              0.01%w/v

(d)     Chlorhexidine acetate                                –              0.01%w/v

(e)     Chlorbutol                                                     –              0.5%w/v

(f)      Thiomersal                                                    –              0.1%w/v

(iii) Active ingredients:

                Water soluble drugs:           – Chloramphenicol, Ciprofloxacin, Gentamicin, Pilocarpine, Atropine

                Water insoluble drugs         – Hydrocortisone acetate

(iv) Viscosity building agents

                They are used in some special eye-drops for prolonged action of the drug;

                e.g.          Hydroxy propyl methyl cellulose (HPMC or Hypermellose)

                                Polyvinyl alcohol (PVA)

 

Procedure

Preparation of eye-drops consists of 4 – stages:

(i)       Preparation of bactericidal and fungicidal vehicles.

(ii)     Solution of the medicament(s) *(i.e. active ingredients) and if appropriate the adjuncts.

(iii)    Clarification

(iv)   Sterilization

Step-I: Preparation of vehicle

The preservative of choice is dissolved in purified water in the prescribed concentration.

Step-II: Solution of medicament(s) and adjuvants

All the medicaments and adjuvants are dissolved in the antimicrobial solutions to form a stabel mixture.

Step-III: Clarification

To remove any particulate matter the solution is clarified by passing through membrane filter having pore size of 0.8mm. The clarified solution is immediately transferred into final containers and sealed.

Step-IV: Sterilization

The eye-drops are sterilized by any one of the following sterilization methods:

(a)     Autoclaving

(b)     Heated at 98 to 100⁰C for 30 minutes.

(c)     Filtration through membrane filter (pore size 0.22mm)

Containers:

Eye drops are dispersed in neutral glass container. Either glass dropper or plastic cap-nozzle is used.

Labeling:

Eye drops should be labeled for external use only along with storage conditions to maintain full activity.