The purpose of this investigation was to increase the gastric residence time of Glipizide, an oral anti-diabetic drug, which is weakly acidic in nature and has absorption window in the gastric region. Gastro retentive drug delivery system of Glipizide was prepared as floating matrix tablets by employing different grades of HPMC, Sodium CMC and Methyl Cellulose using both effervescent and non-effervescent techniques. Sodium bicarbonate was incorporated as a gas-generating agent and the effect of concentration of citric acid on floating properties was investigated. The ratio of polymer was optimized to achieve required buoyancy for the tablets. The formulated tablets were evaluated for uniformity of weight, hardness, friability, drug content, in-vitro buoyancy and dissolution studies by USP type-II method and modified beaker method. The selected formulations exhibited satisfactory physico-chemical characteristics and showed good in-vitro buoyancy for up to > 24 hrs. The integrity of the matrix tablet and stability was good and also showed sustained drug release. The effect of hardness on floating behavior of the tablets was evaluated. The release kinetics of the tablets was studied to predict the mechanism of drug release in-vitro. The in-vivo x-ray study was performed in the healthy male rabbits, to prove the floating behavior of the tablets. The appearance of the tablets in the upper part of the stomach and its position confirmed the in-vivo floating behavior.
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