Ophthalmic drug delivery systems—Recent advances

Recent developments in ophthalmic drug delivery

Transport of drugs applied by traditional dosage forms is restricted to the eye, and therapeutic drug concentrations in the target tissues are not maintained for a long duration since the eyes are protected by a unique anatomy and physiology. For the treatment of the anterior segment of the eye, various droppable products to prolong the retention time on the ocular surface have been introduced in the market. On the other hand, direct intravitreal implants, using biodegradable or non-biodegradable polymer technology, have been widely investigated for the treatment of chronic vitreoretinal diseases. There is urgent need to develop ocular drug delivery systems which provide controlled release for the treatment of chronic diseases, and increase patient’s and doctor’s convenience to reduce the dosing frequency and invasive treatment. In this article, progress of ocular drug delivery systems under clinical trials and in late experimental stage is reviewed.

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Recent Advances in Ocular Drug Delivery Systems

Industrial perspective in ocular drug delivery.

Topical semi-solid drug delivery: kinetics and tolerance of ophthalmic hydrogels

A new novel delivery system for ophthalmic drugs was developed using an antiglaucoma agent Betaxolol Hydrochloride as a model. The new delivery system involved both the binding and release of drug from ion exchange resin particles. Betaxolol was studied in-vitro via a release model analysis. The ocular comfort of Betaxolol was greatly enhanced by reducing the availability of free drug molecules in the precorneal tear film. The amount of resin concentration was selected to obtain optimum binding of the drug. The zeta potential of suspended particles was adjusted to produce flocculated suspension. Drug resin particles were then incorporated into the structured vehicle, containing Carbomer 934P as a polymer, to enhance the physical stability and ease of resuspendability of the product. This delivery system also optimized the bioavailability of Betaxolol, reducing the total drug concentration in half to 0.25% Betaxolol in 0.25% BETOPTIC S Ophthalmic Suspension as compared with 0.5% Betaxolol in BETOP...

Y. Ali

Papers

Ion Exchange Resins for Ophthalmic Delivery