Objective: To optimize and evaluate the formulation of metronidazole (MT)-loaded chitosan microspheres and to investigate the efficiency of biodegradable polymer in developing sustained release formulation of MT to prolong the action of drug.Methods: MT microspheres were prepared using emulsion cross-linking method. Polymer-drug compatibility study was done using Fourier transform infrared. Physical characteristics were evaluated by particle size,SEM, flow properties etc. In vitro studies for evaluating drug release for MT-loaded chitosan microspheres were done by dissolution study.Results: Particle size of the formulated microspheres was found to be within the range of 110-130 μm. Flow properties of F1-F7 such as angle of repose, bulk density, and tapped density were found to be within limits. Drug entrapment efficiency was found to be better for all the formulations within the range of 74.82-84.32% w/w. Drug loading capacity was found to be in the range of 56-83.2% w/v. In vitro drug release was found to be in the range of 81.32-96.23% w/v.Conclusion: In spite of all the above results, we conclude that F5 formulation was optimized depending on the data obtained from the drug loading capacity and percentage drug release studies. F5 formulation is formulated with drug-polymer ratio 1:2 with 1% of di octyl sodium sulfo succinate and 8 ml of glutaraldehyde as a cross-linking agent
