Development and evaluation of glipizide floating tablet

The purpose of this research was to develop a novel gastroretentive drug delivery system based on effervescent technology for controlled delivery of active agent. Glipizide, a poorly soluble drug has been used as a model drug and an attempt has been made to improve the solubility of drug by the incorporation of accelerating agents, such as dispersant, alkalizing agent in conjunction with hydrophilic swellable polymer such as hydroxypropylmethylcellulose and present it in the form of gastroretentive floating tablets, which are designed to provide the desired controlled and complete release of drug for a prolonged period of time. Floating tablets were prepared by direct compression method. Hydroxypropylmethylcellulose (HPMC K15M, HPMC K100M) and Carbopol 940P were incorporated for gelforming properties. Buoyancy was achieved by adding an effervescent mixture of sodium bicarbonate and anhydrous citric acid. The optimized formulation (F7) exhibited 98.60 % drug release in 24 h, while the buoyancy lag time was 140 s. In vitro drug release kinetics were found to follow both the zero order and the Korsmeyer and Peppas equation. The release of glipizide from the formulations was found to be non-Fickian type. Evaluation of gastric retention using X-ray imaging studies were performed on rabbit to justify the increased gastric residence time of the dosage form in the stomach, based on the floating principle. Optimized formulation (F7) showed no significant change in physical appearance, drug content, total buoyancy time, or in vitro dissolution pattern after storage at 40 degrees C175 % relative humidity for I month.