OPHTALMIC, NASAL & OTIC PREPARATIONS Ms. RIFFAT YASMIN
Objectives • Discuss types of Ophthalmic Dosage forms with examples • Interpret the Advantages & Disadvantages of : 1. Ophthalmic solutions a) Ophthalmic Gel forming solutions b) Powders for Ophthalmic solutions 2. Ophthalmic Suspension 3. Ophthalmic Ointment 4. Ophthalmic Emulsion 5. Ophthalmic Gels 6. Ophthalmic Inserts
Ophthalmic solutions Advantages: Ingredients are completely dissolved, inexpensive manufacturing, accepted standard of care. Disadvantages: Messy, compliance issues, short residence time, dilution and washout, require high drug concentration, systemic side-effects *A thickening agent may be used to increase the viscosity but there is a chance to develop residue in the eyelashes.
Ophthalmic Gel-forming solutions These are aqueous solutions of polymer having low viscosity that forms a gel in contact with the tear protein, pH change, temperature change. Advantages: Ingredients are completely dissolved. Adequate contact time of medicament with the eye Disadvantages: It may develop residue in the eyelashes.
Powders for solutions • Due to least instability of the drug in an aqueous solvent some ophthalmic products are available in dry powder form that requires reconstitution by the pharmacist prior administration. Instruction: Aseptic environment is required for reconstitution to maintain efficacy of the product.
Ophthalmic Suspensions These are aqueous suspensions of one or more medicament. Advantages: Adequate contact time of medicament. Increased duration of action. Disadvantages: It may develop residue in the eyelashes.
Ophthalmic Ointment • These are anhydrous, containing Liquid paraffin, Wool fat and Yellow soft paraffin in the proportions 1:1:8. • They are used for therapeutic and diagnostic purposes and contain drug such as Antimicrobial, Corticosteroid & NSAIDs, Advantages: Having increase contact time Good bioavailability Disadvantage: Interfere with vision (they are mostly used at bed time i.e. HS)
Ophthalmic Emulsion It mostly comprised of water & castor oil (as oily phase) Advantages: • Possesses the ability to deliver the poor water soluble drug in solublized form as eye drops. • O/W emulsion is less irritant to the eye. • Increase contact time • Good bioavailability Disadvantage: W/O emulsion may interfere with vision
Ophthalmic Gel • In the making of ophthalmic gels, Carbomer (polymer) is used in aqueous medium. Advantages: Significantly increased contact time Increased drug bioavailability Decreased dosage frequency Disadvantages: Blurred vision due to increased water content
Ocular Insert • Ocuserts are the new drug delivery systems which are designed in such a way that they release the drug at predetermined and predictable rates thus eliminating the frequent administration of the drug. • A drug-dispensing ocular insert containing a drug and suited for application to the eyeball, stay over a prolonged period of time, but the inserts must then be removed when they are no longer needed.
Contd. • The systems generally include controlled, delayed and or sustained release. • e.g. The Pilocarpine inserts used in glaucoma therapy PILOCAR-20, PILOCAR-40.
Reference: • Ansel’s: Pharmaceutical Dosage Forms & Drug Delivery Systems (8th Ed): by Howard C. Ansel Chapter: 17 • Pharmaceutical Practice: by D.M Collette Chapter: 28 • Remington: The Science & Practice of Pharmacy