Characterization Of Glipizide-Loaded Polymethacrylate Microspheres Prepared By An Emulsion Solvent Evaporation Method

Purpose: The purpose of the present investigation was to formulate and evaluate microencapsulated glipizide produced by the emulsion – solvent evaporation method, Method: Microspheres were prepared using polymethacrylate polymers (Eudragit® RS 100 and RL 100) by solvent evaporation method and characterized for their micromeritic properties and drug loading, as well as by Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy. In vitro release studies were performed in phosphate buffer (pH 7.4). Result: The resulting microspheres obtained by solvent evaporation method were white and free flowing in nature. The mean particle size of microspheres ranged from 420 - 660 μm and the encapsulation efficiencies ranged from 40.27 - 86.67 %. The encapsulation efficiency was also found to be dependant on nature of polymer used in the formulation. The infrared spectra confirmed the stable character of glipizide in the drug-loaded microspheres. Scanning electron microscopy revealed that the microspheres were spherical in nature. From the in vitro drug dissolution studies it was found that the sustaining effect of microspheres depended on the polymer concentration, amount of dispersant used and the type of polymer used in the formulation. The mechanism of drug release from the microspheres was found to be non-Fickian type. Conclusion: Eudragit® microspheres containing glipizide could be prepared successfully by using an emulsion solvent evaporation technique using polymethacrylate polymers, which will not only sustain the release of drug but also manage the complicacy of the diabetes in a better manner. Keywords: glipizide, Eudragit®, microspheres, controlled release, polymethacrylate.Tropical Journal of Pharmaceutical Research Vol. 7 (1) 2008: pp. 879-88