Formulation and Evaluation of Glipizide Hollow Microballoons for Floating Drug Delivery

The present investigation was aimed to formulate and evaluate the gastro-retentive floating microballoons of glipizide using hydrophilic polymers hydroxypropyl methylcellulose (HPMC) and Eudragit RS100 (RS 100) by emulsion solvent evaporation technique. The floating microballoons were evaluated using micromeritic properties, buoyancy, in vitro drug release, scanning electron microscopy and stability studies. The densities of floating microspheres (0.475-0.975 g/cm3) were found to be less than the density of gastric fluid (1.004 g/cm3), therefore showed an extended floating time of more than 12 h over the gastric fluid. The entrapment efficiency of prepared floating microspheres was satisfactory (41.32-76.19%). The scanning electron microscopy confirmed the hollow nature of microspheres with pores on the surface which imparted floating properties to the prepared floating microballoons. Among all formulations, F4 (Drug:HPMC:RS 100::1:4:3) was found to be the best as it exhibited highest drug release (99.12%) in 12 h followed by diffusion mechanism and was stable for three months at ambient conditions.