Floating microspheres are gastro retentive low density drug delivery systems based on non-effervescent approach. These systems have density less than gastric fluids and so remain buoyant in stomach without affecting gastric emptying rate for a prolonged period of time. The aim of the present work was to formulate and evaluate floating microspheres containing Mefenamic acid which is a non-steroidal anti-inflammatory drug in order to achieve an extended retention in the upper GIT, which may

more »

... in enhanced absorption and thereby improved bioavailability. Floating microspheres of Mefenamic acid were prepared by an emulsion solvent evaporation method by using different grades of polymers like HPMC K4M, HPMC K15M, Ethylcellulose, excipients and other solvents. FTIR studies confirmed that there were no incompatibilities between drug and polymer. SEM analysis of the microspheres revealed that all the prepared microspheres were discrete spherical in shape with satisfactory surface morphology. The prepared microspheres were evaluated for various parameters like percentage yield, particle size analysis, micromeritic studies, percentage drug entrapment efficiency floating test, in-vitro drug release studies, in-vitro kinetic studies and stability studies. Floating lag time and floating time duration were found to be in the range of 5-10.7 mins, and 5-9.7 hours respectively. All the prepared formulations showed good % buoyancy in the range 53.94 to 70.19%.The in-vitro kinetic studies of the optimized formulation F4 were carried out and found that it undergoes zero order kinetics based on regression coefficient (r2) values. The mechanism of drug release of optimized formulation was found to be case II transport. Among all formulations,F4 showed an appropriate balance between buoyancy and in vitro drug release rate (94.89% in 10 hours), hence it was considered as the best optimized formulation. The stability study was carried out on optimized formulation F4 as per ICH guidelines.