Study of the Mucoadhesive Potential of Carbopol Polymer in the Preparation of Microbeads Containing the Antidiabetic Drug Glipizide

The present investigation was aimed at exploitation of the mucoadhesive potential of carbopol 934P polymer in developing microbeads of glipizide (GLP) for its effectivity in controlling blood sugar in diabetic patients. Various batches of GLP beads were prepared by an emulsion-solvent evaporation technique using the release-retarding polymer carbopol and subjected to a systematic evaluation such as physical characterization, ex vivo mucoadhesion, hydration and erosion test, and in vitro drug release; and instrumental and in vivo studies were performed with the best formulation. The highest yield and loading efficiency were observed as 94 and similar to 90%, respectively. The mean particle size of the microbeads ranged from 832 to 742 mu m. The oval shape of the microbeads with slight roughness was apparent in the SEM micrograph. The release period was extended till 18 h. In vitro release of the drug from the beads followed the diffusion and erosion mechanism. In the oral glucose tolerance test (OGTT), there is a significant (p<0.01) reduction in fasting blood glucose levels in Wistar rat and guinea pig in comparison with that using the marketed product. Results indicated that process parameters-drug-polymer ratio, concentration of the surfactant, and stirring speed-controlled the various characteristics of the microparticles. The mucoadhesivity test ensured strong adherence of the beads to the mucosal membrane in pH 1.2 for a prolonged period. Owing to the mucoadhesivity of carbopol 934P, prolonged release of GLP and reduction of fasting sugar in the animal model were observed to a satisfactory level, and thus, management of diabetes in a better manner is expected with this new formulation.