Development of Low Density Microspheres of Metformin Hydrochloride Using Ethyl Cellulose and HPMC K4M:In Vitroandin VivoCharacterization

Polymeric floating microspheres of metformin hydrochloride were prepared by a modified solvent evaporation method using ethyl cellulose and HPMC K4M. Microspheres were characterized by SEM, particle size, drug content, in vitro swelling, in vitro buoyancy, in vitro drug release and in vivo X-ray imaging. Formulation D exhibited in vitro swelling, about 48.28 ± 1.03% and the desired floating time and with retention in the upper small intestine of rabbits for 8 h and with release for 12 h. We conclude that ethyl cellulose and HPMC K4M at 0.40:1.50 w/w ratios could be an effective carrier for multiparticulate controlled drug delivery.