Formulation and evaluation of gastroretentive floating bioadhesive tablets of glipizide

Abstract

The purpose of present investigation was to develop and characterize a Novel Gastroretentive Drug Delivery System of Glipizide in the form of Floating and Bioadhesive Tablet which possesses a unique combination of floatation and bioadhesion properties. It was aimed to prepare for prolonged residence in the stomach over conventional Gastroretentive approaches. The tablets are produced by direct compression method by using HPMC K4M, HPMC K15M and HPMC K100M as hydrophilic polymers and Carbopol 974P as Bioadhesive polymer along with other requisite excipients in different combinations and proportions. Glipizide is a second-generation sulfonylurea drug which is typically prescribed to treat type II diabetes (non-insulin dependent diabetes mellitus). Its short biological half-life (3.4 ± 0.7 hours) necessitates that it be administered in 2 or 3 doses of 2.5 to 10 mg per day. Moreover, the site of absorption of Glipizide is in the stomach. Thus, the development of Gastroretentive dosage forms would clearly be advantageous. The prepared tablets were evaluated for different parameters such as thickness, hardness, weight uniformity, content uniformity, floating lag time, floating duration, swelling index, in vitro drug release, ex vivo bioadhesive strength, stability studies, and DSC, FTIR studies. The prepared tablets exhibited satisfactory physical parameters and good in vitro buoyancy. The modified in vitro assembly was used to measure the bioadhesive strength of tablets with fresh gastric mucosa of a goat as model tissue. Bioadhesion strength was increased with increase in the concentration of Carbopol. The tablets were evaluated for in vitro release in 1.2 pH buffer 0.1 N HCl. The in-vitro drug release of floating tablets (n=3) followed Fickian diffusion controlled release and are best explained by Higuchi equation. Carbopol 974P and HPMC K15M combination could be used to design effective and stable floating and bioadhesive tablets of Glipizide. The present study concludes that floating and bio-adhesive tablets of Glipizide are potential dosage form due to its prolonged residence in stomach as compared to conventional stomach specific dosage forms.