Ophthalmic productsdefinitionrequirements types of additives

Definition of ophthalmic products

Definition

Ophthalmic preparations (eye preparations) are sterile, liquid, semi-solid, or solid preparations that may contain one or more active pharmaceutical ingredients or drugs used for application to the conjunctiva, the conjunctival sac or the eyelids.

Types of preparations

1-liquid form : this preparation mostly contains aqueous vehicle , like eye drops and lotion .

2- semi-solid form: like ointments,gels and creams that based on aqueous and oil to applied to the margin of the eyelid and conjunctival sac.

3- solid form : drugs in pellet or flake forms , it is put in conjunctival sac for modified releasing time ( prolonged time)

Types of preparations

The newest dosage forms for ophthalmic drug delivery are: gels, ocular inserts , intravitreal injections and implants.

The most commonly employed ophthalmic dosage forms are solutions, suspensions, and ointments.

Requirements

1 -foreign particles2 -viscosity

3 -Tonicity4-PH of preparation

5 -sterility6 -surface activity

Requirements

1 -foreign particles : all ophthalmic products should be clear and free from foreign particles ,

Ophthalmic solutions should be clarified very carefully by passing through bacterial proof filters such as membrane filters.

The particle size of eye suspension should be in an ultrafine state of subdivision to minimize irritation , its range from 10 nm-

100nm

A separate filter should be used for different ophthalmic products in order to avoid the contamination.

Requirements2 -viscosity :

In order to prolong the contact time of the drug in the eye , various thickening agents are added in ophthalmic preparations .

Polyvinyl alcohol (1-4%), polyethylene glycol , methyl cellulose , carboxy methyl cellulose are some of the commonly used thickening

agents. These agents improve the viscosity of the preparation .

An ideal thickening agents should be possess the following properties:

1 -it should be easy to filter.

2 -it should be easy to sterilize.

3 -it should be compatible with other ingredients .

Requirements

3 -Tonicity:Ophthalmic products should be isotonic with lachrymal secretions to avoid discomfort and irritations .

NaCl, there are certain isotonic vehicles which are used to prepare ophthalmic products like 1.9% boric acid , sodium acid phosphate buffer .

It has been observed that eye can tolerate a range of tonicity from (0.5 to 2%)

Requirements

4 -ph of the preparation :

ph plays an important role in therapeutic activity , solubility, stability and comfort to the patient

Tears have a ph about 7.4 , eye can tolerate solution having wide range of ph provided they are not strongly buffered.

.

Requirements

5 -sterility : ophthalmic preparations must be sterile when prepared

pseudomonas aeroginosa Is very common gram negative bacteria which is generally found to be present in ophthalmic products . It may cause serious

infections of cornea . It can cause complete loss of eye sight in 24-48 hours.

To maintain sterility in multi dose container , containing ophthalmic products , a suitable preservative is added . The

preservative should be non-toxic , non-irritant

compatible with medicaments . The ophthalmic products are generally sterilized by autoclaving

Requirements

6 -Surface activity : vehicles used in ophthalmic preparations must have good wetting ability to penetrate cornea and other tissues.

Certain surfactants or wetting agents added which are found

suitable for ophthalmic products .It should not cause any damage to the tissue of eye.

Benzalkonium chloride , polysorbate 20 , polysoabate 80 , dioctyl sulpho succinate etc, are some of the surfactants which are commonly used.

Types of Additives

1 -Antioxidants : especially sodium bisulfate or metabisulfate and also, ascorbic acid or acetylcysteine.

It is used for prevention oxidation of drug and inhibit free radical matters.

2 -surfactants : surfactant are often used to stabilize more hydrophobic drugs .

Nonionic surfactants, are used most often since they generally less irritating than ionic surfactants. Polysorbate 80 is used in preparation of ophthalmic emulsions. Polyoxyl 40 stearate and polyethylene glycol has been used to solubilize a drug in an

anhydrous ointment .

Cationic surfactants, are used gradually in the eye solution but almost invariable as an antimicrobial preservative .

Types of Additives

3 -preservative : Benzalkonium chloride as a preservative is used in large quantities in commercial eye solution and suspension, preservative Should be use in multi ophthalmic

dose but in single dose they arent demand .

Done by:

Ali-AlghamdiMohammed Ali Saleh Al-ghamdi

Abdullah basheikTurki Al-Anani

Fahad A.AL-mutairiRakan khalaf

The End