Formulation and Evaluation of Floating Microsphere of Captopril using Different Gas Forming Agents.

The present study involves preparation and evaluation of floating microsphere of Captopril as model drug for prolongation of gastric residence time. the different gas forming agents are used such as sodium bicarbonate and calcium carbonate. The microsphere were prepared by Ionotropic gelation technique using polymers Sodium alginate along with HPMC (K4M) and Ethyl cellulose. The microsphere was evaluated for angle of repose, bulk density, tapped density, Carr’s index, Hausner's ratio, percent yield and drug entrapment. The shape and surface morphology of prepared microsphere were characterized by optical and scanning electron microscopy, respectively. In-vitro drug release studies were performed by using an USP dissolution test apparatus (type I) at 37±0.5ºC and 50 rpm speed.  To study the release behaviour, kinetic analyses were performed on the optimized formulation. The dissolution data were fitted to zero order, first order, matrix, Hixson-Crowell, Peppas model. The prepared microsphere exhibited prolonged drug release (~ 12 hr) and remained buoyant for > 12 hr.  The optimized formulations H3, H6 were kept for short term stability study. The conditions for stability study were 40ºC and relative humidity of 75% from the study; it was observed that there is no significant change in drug entrapment and drug release rate. Key-words: Floating microsphere, Captopril, In-vitro release, HPMC (K4M), Ethyl Cellulose