FORMULATION, CHARACTERIZATION AND IN VITRO EVALUTION OF GABAPENTIN FLOATING MICROSPHERES

The present study involves the design and characterization of floating microspheres with gabapentin as model drug for prolongation of gastric residence time. Gabapentin floating microspheres were prepared by o/w/o emulsification solvent diffusion technique using ethyl cellulose as the rate controlling polymer at various concentrations. The shape and surface morphology of microspheres were characterized by optical and scanning electron microscopy. Absence of drug-polymer interaction was confirmed by FTIR analysis. In vitro drug release studies were performed and drug release kinetics was evaluated using the linear regression method. Effects of polymer concentration, solvent composition, particle size, drug entrapment efficiency and drug release were also studied. The synthesized microspheres exhibited prolonged drug release (> 12 h) and remained buoyant for > 24 h. The drug entrapment efficiency was in the range 46-70 %. At higher polymer concentration, the average particle size was increased and the drug release rate decreased. In vitro studies revealed diffusion-controlled drug release from the microspheres. Among all the formulations (F1-F5), F4 is the optimized formulation.