Formulation and Evaluation of Modified Pulsincap Technique for Oral Controlled Release of Glipizide

In-vitro controlled release of glipizide was studied from modified pulsincaps prepared by using different proportions of the polymer HPMC. Glipizide – HPMC mixtures were prepared in the ratios 5:1, 5:2, 5:3 and 5:4 respectively. These mixtures were evaluated for micromeritic properties and to confirm the reproducibility of method of mixing. Micromertic properties of the pure drug glipizide and glipizide – HPMC mixtures were improved by the incorporation of spray-dried lactose (pharmatose) at 15% of the weight of the drug. Drug polymer interaction studies were performed on the selected drug - polymer mixtures and on the pure drug , glipizide by using FTIR and DSC. These studies showed no drug polymer interactions.Drug - polymer mixture equivalent to 10mg of glipizide was used for the preparation of modified pulsincaps. The prepared modified pulsincaps were evaluated for weight variation, drug content and drug release from the prepared modified pulsincaps. Glipizide release from the prepared modified pulsincaps was slow and extended for a period of time not less than 10 hrs, depending upon the concentration of the polymer used. Drug release was diffusion controlled and followed zero order kinetics. The release of glipizide from GH₁ and GH₂ pulsincaps was close to the release of glipizide from a commercial SR tablet Glytop.