FORMULATION AND EVALUATION OF OCULAR NIOSOMAL IN SITU GELS OF LINEZOLID

Niosomes, an emerging class of novel vesicular systems, are non-ionic surfactant vesicles which can entrap both hydrophilic and lipophilic drugs. Niosomes are incorporated into in situ gels for sustained release of drug and to prolong the residence time. The aim of present study is to formulate and evaluate ocular niosomal in situ gels of Linezolid. Linezolid is a potent synthetic oxazolidinone derivative active against a broad range of gram positive and gram-negative aerobic and anaerobic bacteria. Niosomes were prepared using various surfactants (span 20, span 40, span 60 and span 80) in different ratios using thin film hydration technique. They were evaluated for particle size, entrapment efficiency and in vitro drug release. Niosomes prepared using cholesterol and span 60 in the ratio 1:2 showed higher entrapment efficiency and better in vitro drug release. The optimized formulation was formulated as in situ gels using Carbopol 971P and HPMC K4M in different ratios and evaluated for gelling capacity, pH, viscosity, in vitro drug release, drug content, antimicrobial activity and ocular irritation test. The gels retained its antimicrobial efficacy and were proved to be safe and non-irritant on rabbit eyes. The niosomal in situ gel is a viable alternative to conventional eye drops by virtue of its ability to enhance bioavailability through its longer precorneal residence time and ability to sustain drug release.