ABSTRACT
Conventional ophthalmic formulations like solution, suspension, and ointment have many disadvantages which result into poor bioavailability of drug in the ocular cavity. The poor bioavailability and therapeutic response exhibited due to precorneal elimination of the drug may be overcome by the use of mucoadhesive in situ gel forming systems that are instilled as drops into the eye and undergo a sol-gel transition in the cul-de-sac and have good mucoadhesion with ocular mucus layers. The objective of this study was to formulate ophthalmic mucoadhesive system of gatifloxacin (GTN) and to evaluate its in vitro antibacterial potential against, Staphylococcus aureus and Escherichia coli. Mucoadhesive systems were prepared by using polaxamer 188 combined with chitosan to enhance the gel bioadhesion properties. Increase in the concentration of mucoadhesive agent enhanced the mucoadhesive force significantly. In vitro release of gatifloxacin from the mucoadhesive system in simulated tear fluid was influenced significantly by the properties and concentration of chitosan, carbapol 934 showed to enhance bioavailability through its longer precorneal residence time and ability to sustain the release of the drug. Significant reduction in the total bacterial count was observed between drug solution (control) and mucoadhesive batches against both tested organisms.
 

Keywords: Mucoadhesive, gatifloxacin, polaxamer, chitosan, thermoreversible insitu gel, occular drug delivery