To develop and characterize oral gastroretentive floating microsphere of Metformin HCl to prolong gastric residence time for treatment of diabetes mellitus.
Methods: The Gastroretentive floating microspheres of Metformin HCl were prepared by emulsion solvent evaporation method. Eudragit RS-100 and RL-100 were used as polymer. Microspheres were characterized for their percentage yield, entrapment efficiency, particle size analysis, floating behavior, optical and scanning electron microscopy. The in-vitro release evaluation and floating behavior were studied in hydrochloric acid buffer (0.1N HCl, pH-1.2). Different drug release kinetic models were also applied for all the prepared batches of selected drug. Selected formulations were also subjected to in-vivo anti-hyperglycemic activity on albino rat model.
Results: Floating microspheres were successfully prepared by emulsion solvent evaporation technique. The maximum yield of microspheres was upto 84.20%. On the basis of optical microscopy (at 40X) and scanning electron microscopy particle size range of Eudragit based microsphere was found to be ranging from 50 to 200 µm and also spherical in shape and somewhat rough and smooth surfaces when seen at different magnifications. Buoyancy of microspheres were found to be maximum after 12 hr in hydrochloric acid buffer and all formulation shows buoyancy more than 50%. In-vivo studies showed that such drug delivery system of Metformin HCl could be a better alternative approach for the physicians over the existing immediate-release formulations.