Factorial design.

Ophthalmic drug delivery is one of the most interesting and challenging endeavors facing the pharmaceutical scientist. The anatomy, physiology and biochemistry of the eye render this organ highly impervious to foreign substances. The poor bioavailability and therapeutic response exhibited by conventional ophthalmic solutions due to rapid pre-corneal elimination of the drug may be overcome by the use of in situ gel forming systems that are instilled as drops into the eye and then undergo a sol-gel transition in the cul-de-sac. The purpose of the present work was to develop an ophthalmic drug delivery system of Pefloxacin mesylate for in situ gelling system byusing ion sensitive gelling agent (Gelrite) and viscofying agent (HPMCK4M). Optimization by 22 factorial design using Design expert software 8.0 version was applied to the formulations. Formulation with Gelrite (gellan gum) and HPMC K4M shows percent drug content of 99.83%, viscosity of 1864 cp at 20 rpm and in-vitro drug release of 88.32% which shows formulation is good. The developed formulation was found to be stable and provided sustained release of the drug over 8 hours.