Investigating The Retention Potential of Chitosan Nanoparticulate Gel: Design, Development, In Vitro & Ex Vivo Characterization

Introduction The main purpose of the research was to develop, optimize and characterize tobramycin sulphate loaded chitosan nanoparticles based gel in order to ameliorate its therapeutic efficacy, precorneal residence time, stability, targeting and to provide controlled release of the drug. Methods Box-Behnken design was used to optimize formulation by 3-factors (chitosan, STPP and tween 80) and 3-levels. Developed formulation was subjected for characterizations such as shape and surface morphology, zeta potential, particle size, in vitro drug release studies, entrapment efficiency of drug, visual inspection, pH, viscosity, spreadability, drug content, ex vivo transcorneal permeation studies, ocular tolerance test, antimicrobial studies, isotonicity evaluation and histopathology studies. Results Based on the evaluation parameters, the optimized formulation showed a particle size of 43.85 ± 0.86 nm and entrapment efficiency 91.56% ± 1.04, PDI 0.254. Cumulative in vitro drug release was up to 92.21% ± 1.71 for 12 hours and drug content was found between 95.36% ± 1.25 to 98.8% ± 1.34. TEM analysis unfolded spherical shape of nanoparticles. TS loaded nanoparticulate gel exhibited significantly higher transcorneal permeation as well as bioadhesion when compared with marketed formulation. Ocular tolerance was evaluated by HET-CAM test and formulation was non-irritant and well-tolerated. Histopathology studies revealed that there was no evidence of damage to the normal structure of the goat cornea. As per ICH guidelines, stability studies were conducted and were subjected for 6 months. Conclusion Results revealed that the developed formulation could be an ideal substitute for conventional eye drops for the treatment of bacterial keratitis.