Design and development of novel bioadhesive niosomal formulation for the transcorneal delivery of anti-infective agent: In-vitro and ex-vivo investigations

Gatifloxacin eye drops are frequently used in eye infections. However such formulations have a major drawback i.e. short duration of action and usually require 4-6 times installations daily. A chitosan coated niosomal formulation of gatifloxain was purposed to show a longer retention time on eyes and subsequent reduction in dosing frequency. Vesicles were prepared by solvent injection method using cholesterol and Span-60. An extensive optimization of formulation was done using different ratios of cholesterol, Span-60 and drug, revealed NS60-5 (cholesterol: span-60 50: 50 and drug content of 20 mg) to be the optimized niosome formulation. NS60-5 had shown a highest entrapment efficiency of 64.9 +/- 0.66% with particle size 213.2 +/- 1.5 nm and zeta potential -34.7 +/- 2.2 mV. Optimized niosomes were also coated with different concentrations of chitosan and evaluated. Permeation studies had revealed that optimized niosomes (86.77 +/- 1.31%) had increased the transcorneal permeation of Gatifloxacin more than two fold than simple drug solution (37.19 +/- 1.1%). Longer retention potential of the coated niosomes was further verified by fluorescence microscopy. Study revealed that simple dye solution got easily washed out with in 6 h. The uncoated niosomes (NS60-5) showed a longer retention (more than 6 h), which was further enhanced in case of coated niosomes i.e. CNS60-1 (more than 12 h). Antimicrobial studies had shown the better efficacy of CNS60-1 (zone of inhibition) when compared to marketed formulation. The final chitosan formulation was found to have shown better ocular tolerability as demonstrated by corneal hydration test histopathology investigations. (c) 2015 Shenyang Pharmaceutical University. Production and hosting by Elsevier B.V.