Design and Evaluation of Ofloxacin Extended Release Ocular Inserts For Once a Day Therapy

The aim of the study was to develop an extended release ocular insert for once a day therapy for the controlled delivery of ofloxacin and to evaluate its efficacy in vitro and in vivo. Reservoir type ocular inserts of ofloxacin were prepared by solvent casting method. Twelve formulations were developed, which differed in the ratio of polymers Eudragit RS 100 and Ethyl cellulose used for the preparation of the rate controlling membrane and polymer HPMC was used for the preparation of drug reservoir. When commercial semi-permeable membrane was used, the optimized formulation F10 was found to give best release with 97.14% at the end of 24 hours in concentration independent manner and when the same formulation was used to study release rate through excised goat cornea has shown release of 88.51% at the end of 24 hours in concentration independent manner. The above in vitro release studies revealed that the ocular inserts followed zero-order release kinetics. Higuchi's plot and Peppa's plot revealed that the mechanism of drug release involved in all the formulations was super case II transport diffusion. The optimized formulation F10 was applied in the cul-de-sac of albino rabbits and at adequate intervals (12^th and 24^th hr), the tear fluid and aqueous humor were collected and the drug concentration was determined by an HPLC method. The in-vitro and in-vivo studies revealed that good correlation exist between the two and the formulation F10 was capable of releasing the drug in concentration independent manner for the extended period of 24 hours and remained stable and intact at ambient conditions.