Formulation and Evaluation of Glipizide Microemulsion

Glipizide is a second-generation sulfonylurea used in the treatment of Type 2 diabetes mellitus. Because of its poor aqueous solubility (BCS Class II), its oral bioavailability is limited by a slow dissolution rate. Microemulsion-based drug delivery systems are thermodynamically stable, isotropic dispersions of oil, water, surfactant, and co-surfactant that enhance the solubility, dissolution, and bioavailability of poorly water-soluble drugs. In this study, glipizide microemulsion is formulated using the water titration method after selection of suitable oil, surfactant, and co-surfactant based on solubility studies and pseudo-ternary phase diagrams. The optimized formulation is evaluated for droplet size, polydispersity index, zeta potential, pH, viscosity, conductivity, percentage transmittance, drug content, in-vitro drug release, and stability. Studies have shown that optimized glipizide microemulsions] can achieve >90% drug release with nanosized droplets and good physical stability, indicating their potential to improve oral drug delivery.