www.wjpps.com 2065 Kinjal et al. World Journal of Pharmacy and Pharmaceutical Sciences FORMULATION AND EVALUATION OF P H -TRIGGERED IN SITU GEL FOR OCULAR DELIVERY OF NORFLOXACIN Kinjal B. Rathod * 1 , Mandev B. Patel 2 1 K.B. Raval College of Pharmacy, At Shertha, Gandhinagar, Pin- 382423, Gujarat, India. 2 A-One College of Pharmacy, Enasan, Ahmedabad,Gujarat, India. ABSTRACT The poor bioavailability and therapeutic response exhibited by conventional ophthalmic solutions due to rapid precorneal 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 undergo a sol–gel transition in the cul-de-sac. The present work describes the formulation and evaluation of an ophthalmic delivery system of an anti-bacterial agent- Norfloxacin, based on the concept of pH-triggered in situ gelation. Polyacrylic acid (Carbopol- 934) was used as the gelling agent in combination with HPMC K4 M which acted as a viscosity enhancing agent. The developed formulation was therapeutically efficacious, stable, non-irritant and provided sustained release of the drug over a period of 8-hours. The developed system is thus a viable alternative to conventional eye drops. Keywords: Norfloxacin, pH, Carbopol 934, In situ gel INTRODUCTION Extensive research has been carried in designing of polymeric drug delivery systems. The development of in situ gel systems has received considerable attention over the past few years 1 . This interest has been sparked by the advantages shown by in situ forming polymeric delivery systems such as ease of administration and reduced frequency of administration, improved patient compliance and comfort 2 . Smart polymeric systems represent promising means of delivering the drugs; these polymers undergo sol-gel transition, once administered 3 . In situ gel formation occurs due to one or combination of different stimuli like pH change, WORLD JOURNAL OF PHARMACY AND PHARMACEUTICAL SCIENCES Volume 2, Issue 4, 2065-2076. Research Article ISSN 2278 – 4357 Article Received on 26 May 2013, Revised on 29 June 2013, Accepted on 24 July 2013 *Correspondence for Author: * Kinjal B. Rathod Asst. Professor, K.B. Raval College of Pharmacy, At Shertha, Gandhinagar, Pin- 382423, Gujarat, India,. kinjalbt@gmail.com