Formulation and evaluation of bilayered gastro retentive floating tablets containing metformin HCl and glipizide

Bilayer tablets of Metformin hydrochloride and Glipizide were formulated. Glipizide is a poor water soluble (BCS class 2) antidiabetic drug. The present study aims to increase the solubility of Glipizide by solid dispersion technique using sodium starch glycolate and crospovidone as super disintegrants. Metformin hydrochloride was formulated by using Hydroxy Propyl Methyl Cellulose as the matrix forming polymer and was directly compressed. The compressed bilayer tablets were evaluated for all required parameters. It was found that the optimized formulation showed 99% release for Metformin hydrochloride in 24 hours. However, Glipizide released 97% at the end of 60 minutes. The IR spectrum studies revealed that there is no disturbance in the principal peaks of pure drugs alone as well as with the excipients. The stability studies were carried out for the optimized batch for three months and it showed acceptable results. The kinetic studies of the formulations revealed that diffusion is the predominant mechanism of drug and release follows Korsemeyerpeppas diffusion model.