Floating Microcarriers of an Antidiabetic Drug : Preparation and its In-Vitro Evaluation

The purpose of present research work was to prepare floating microcarriers of Metformin hydrochloride. A multipleunit- type oral floating dosage form of Metformin hydrochloride was developed to prolong gastric residence time and increase drug bioavailability with decreased GI side effects. The floating microcarriers were prepared by ionotropic gelation method dispersing Metformin hydrochloride with calcium carbonate and sodium bicarbonate separately into a mixture of anionic sodium alginate, as primary polymer with oppositely charged counter ion polymer namely HPMCK4M, EC and mixture of both the polymer into a solution of calcium chloride containing acetic acid. The prepared microcarriers were evaluated for micromeritic properties, % yield, drug loading, drug entrapment efficiency, particle size and shape, buoyancy and in vitro drug release studies. The formulations were optimized for different weight ratios of gas-forming agent and combination of polymer. The prepared microcarriers were in range of 447.1 to 801.8 μm. The results of these studies indicate that CaCO3 is superior to NaHCO3 as a gas forming agent in polymer combination microcarriers.