Development and optimization of controlled release bioerodable anti infective ophthalmic insert

The present investigation was carried out to formulate and optimize the bioerodable insert of Azithromycin in order to prolong the release time and improve the ocular availability in ophthalmic infections. A modified solvent casting method was used for the preparation of azithromycin insert in which hydroxyl propyl methyl cellulose (HPMC) and Eudragit RL100 were used as drug reservoir and rate controlling membrane respectively. Thereafter the, formulations were evaluated for the uniformity of thickness and weight, surface pH, folding endurance, percentage moisture loss, percentage moisture absorption, drug content, in-vitro release, kinetics studies (zero order, first order, Higuchi and Korsmeyer - Peppas model) and stability studies. The Formulation H8 (amongst the range of H1-H10), comprising of 1.5% HPMC and 3% Eudragit RL100, was found to be optimized formulation on the basis of uniformity of thickness (0.26±0.004 mm) and weight (24.9±0.27 mg), surface pH (7.1±0.063), folding endurance (18.3±0.81), percentage moisture loss (7.49±0.30%), percentage moisture absorption (5.7%), drug content (1.98 mg), in-vitro release (99%), AUC for in vitro and in vivo release is 38828.33 and 39783.33 g min/ml respectively and higher than pure drug (1190 g min/ml), (Shelf life- 622 days) and further better occular tolerablity found. The formulation H8 showed a steady and controlled release of the drug over a 12 hour period with non-Fickian diffusion release mechanism, compared to a normal release period of 2-3 hours. The optimized insert showed promising results and can be used to treat a wide range of ocular infections.