Formulation and Evaluation of Gelritabased in Situ Opthalmic Gel for Controlled Release of Drug Using Rabbit Eye Model

Abstract

The purpose of our work to formulate and evaluate an ophthalmic delivery system of a fluoroquinolone antibiotic, levofloxacin. Levofloxacin is an antibacterial agent which exhibits rapid precorneal elimination and poor ocular bioavailability, when given in the form of conventional ophthalmic solutions. To overcome this, an attempt has been made to formulate in situ gelling system of levofloxacin, based on the concept of ion-activated in situ gelation, which upon instillation as drops into the eye undergo a sol-gel transition in the cul-de-sac. This may result in better ocular bioavailability and provide sustained release of the drug. Gelrite®gellan gum, a novel ophthalmic vehicle, which gels in the presence of mono or divalent cations present in the lacrimal fluid, was used as the gelling agent in combination with HPMC (Methocel E50LV) which acted as a viscosity enhancing agent. The formulations were evaluated for rheological characteristics, in vitro release behavior, antimicrobial efficacy and ocular irritancy studies. We found that in situ gelling formulations passed the test for sterility. These results demonstrate that the gellan gum-HPMC mixture can be used as an in situ gelling vehicle to enhance ocular bioavailability and patient compliance. The developed formulation was stable, non-irritant and provided sustained release over 8-hour period and it can be considered as a viable alternative to conventional eye drops