Levofloxacin hemihydrate ocular semi-sponges for topical treatment of bacterial conjunctivitis: Formulation and in-vitro/in-vivo characterization

This study aimed to formulate and evaluate lyophilized, long acting, levofloxacin hemihydrate ocular semi-sponges that would fit cul-de-sac shape for bacterial conjunctivitis treatment. Formulae were prepared using casting/freeze drying technique employing a (4(1) x 3(1)) full factorial design to examine the effects of polymer type (Gelrite, chitosan (low and high molecular weight), and sodium carboxymethylcellulose), and concentration (1%, 1.5%, 2%) on viscosity of the formed solutions, quantity of drug released after 12 h (Q12h) and time for 50% of the drug to be released (T-50%). Formulae were evaluated for weight and content uniformity, surface pH, water uptake, and in vitro drug release with its kinetic analysis. The optimal formula was chosen using Design-Expert (R) software and subjected to scanning electron microscope imaging, gamma-sterilization and in-vivo evaluation. Results showed that formula G 2 (2% w/w Gelrite) had the highest desirability (0.894), a zero order drug release profile, and stability after gamma-sterilization. Formula G 2 showed longer residence time (12 h) in rabbits' eye fluids compared to the commercial Levoxin (R) eye drops (4 h) with good correlations between in vitro and in vivo results. Conclusively, Gelrite ocular levofloxacin hemihydrate semi-sponges are promising drug delivery systems that would improve both patient compliance and treatment efficacy. (C) 2015 Elsevier B.V. All rights reserved.