Thermosensitive In situ Gel for Ocular Delivery of Lomefloxacin

Abstract:

The temperature sensitive in situ gel formulations, undergo phase transition from liquid to semisolid gel upon exposure to physiological eye temperature. These are free-flowing liquid at room temperature and easy to administer into the eye as drops. They undergo in situ phase transition to form a strong gel that is capable of withstanding shear forces in the culde-sac and of sustaining drug release at physiological conditions. Lomefloxacin hydrochloride is a broad spectrum, second generation fluroquinolone antibiotic used to treat various conjunctival infections. Present work describes the formulation of thermoreversible sol gel of Lomefloxacin hydrochloride using Pluronic F127, Pluronic F68 and sodium alginate. The prepared formulations were evaluated for various parameters such as clarity, pH, drug content, gelation capacity, gelation temperature, gelling strength, viscosity, in vitro release studies, pharmacokinetics studies, ex vivo permeation studies, antimicrobial activity animal studies and short term stability studies. The pH was in range of 7-7.5. The viscosity of the formulations at 250±20C and 370±20C was in the range of 50-60 cps and 1590-3370 cps respectively. The results obtained were in agreement with the phase transition and there was no significant change in the viscosity of formulation when diluted with simulated tear fluid. The in vitro drug release revealed a sustained profile of 8 hours and optimized formulation showing 89.3% of release. Short term stability study indicated that 40±10C is appropriate storage condition for the formulations.

Key words: Lomefloxacin, Pluronic F127, Thermoreversible sol gel, Cold technique, Phase transition, Shear thinning systems.