In the present study, an attempts were made to formulate buccal patches of glipizide using bioadhesive polymers to avoid the hepatic first pass metabolism, to achieve controlled release and to improve better clinical efficacy. Buccal patches of glipizide were designed using ethylcellulose (EC) alone and blends of EC:Polyvinylpyrrolidone (PVP K- 30) at different ratios using glycerol as plasticizer adopting solvent evaporation method. All patches were evaluated for physical appearance, surface texture, weight uniformity, thickness uniformity, folding endurance, surface pH, swelling index, moisture content and absorption, bioadhesive strength, drug content uniformity. Various bioadhesive parameters like bioadhesive strength, force of adhesion, and bond strength exhibited by various patches of glipizide was satisfactory. All buccal patches of glipizide showed sustained and prolonged release the drug over a period of 8 h. When the patches were prepared with the blends of EC:PVP the flux and permeation rates were increased compared to patches prepared with EC alone. The increasing order of drug release from the EC:PVP patches was found in the order, A4 > A3 > A2 > A1 (i.e., 1:1 > 1:0.75 > 1:0.5 > 1:0.25). Further, increase in concentration of EC has a negative effect on drug release i.e., drug release decreased with increase in concentrations of EC. The release of glipizide from all patches followed Higuchi kinetic model and the mechanism of drug release was concluded as non–Fickian diffusion controlled.
