FORMULATION AND EVALUATION OF SUSTAINED RELEASE OCULAR DRUG DELIVERY SYSTEM FOR AN ANTI-GLAUCOMA DRUG

Abstract

Glaucoma is one of the leading causes of irreversible blindness globally, which requires long-term pharmacological management. The current treatment approaches face issues in terms of poor patient compliance with the drugs mainly because of their infrequent dosing requirements and significant ocular side effects. This work is aimed at designing and testing a sustained-release ocular drug delivery system for an anti-glaucoma drug, thereby improving bioavailability and reducing dosing frequency. We synthesized the microparticles using biodegradable polymers with timolol maleate as a prototype anti-glaucoma drug. The microparticles were characterized by particle size, drug entrapment efficiency, in vitro release kinetics, and ex vivo corneal permeation. In vivo studies in rabbits assessed the intraocular pressure lowering efficacy and ocular tolerability. Results showed successful formulation of the microparticles with a mean particle size of 10-15 μm and drug entrapment efficiency of 75-80%. The drug was found to release sustainably over 72 hours, following Higuchi kinetics from in vitro studies. There was higher penetration of the drug compared to conventional eye drops noted in ex vivo corneal permeation studies. In vivo studies presented significant as well as prolonged lowering of IOP up to 72 hours without showing any ocular irritation symptoms. This new formulation has a tremendous potential as an appropriate, well-tolerated, and patient-friendly alternative for the management of glaucoma and thus may prove better in terms of therapeutic outcomes through enhanced delivery of the drug in lower dosing frequencies.