Chitosan Encrusted Nonionic Surfactant Based Vesicular Formulation for Topical Administration of Ofloxacin

This investigation describes a surfactant based elastic vesicular novel drug delivery system (NODS, niosomes) to enhance residence time of Ofloxacin (OFX, a fluoroquinolones antimicrobial agent) in tear film and to attain its sustained delivery at ophthalmic site. Optimized niosomal formulation constituted of Span 60 and Cholesterol (Choi) was characterized and monitored for safety, efficacy and stability. Different formulation batches were prepared by using varying concentrations of chitosan ranging between 0.1 to 0.5% w/v, while using span 60 and Chol at constant molar ratio of 2:1 (w/w). Positive surface electric charge confirmed successful coating of chitosan over encrusted niosomal formulations. Stability profile assessed at varying temperatures revealed growth in vesicular size 13.40 +/- 1.16% with petite aggregation and no significant physical damage. The formulation C4N5 containing span 60:Chol 2:1 w/w and chitosan 0.4% w/v showed maximum entrapment (78.51 +/- 1.33%), sustained release pattern (98.59 +/- 0.17% after 8 h), and significant mucoadhesive characteristics (p < 0.05); with no signs of irritation, swelling and redness to conjunctiva, iris and cornea of albino rabbits. Further, assessment of C4N5 formulation for antimicrobial activity revealed significant (p < 0.005) zone of inhibition (34.34 +/- 0.52 mm), in contrast to clinically approved OFX (Zenox (TM) Eye drop, Zen labs, Chandigarh, India; 22.0 +/- 1.0 mm) against S. aureus species.