In vitro evaluation of porous carrier-based floating granular delivery system of orlistat.

The purpose of the study is to prepare and evaluate an intragastric floating granular delivery system of orlistat using (i) calcium silicate as porous carrier; and (ii) hydroxypropyl methylcellulose K4M, ethyl cellulose, and Carbopol 940 as matrix-forming polymers. The effect of various formulation and process variables on the micro-meritic properties, in vitro floating behavior, percent drug content, and in vitro drug release was studied. The release mechanism of orlistat from these granules was evaluated on the basis of various theoretical equations. The optimized formulation demonstrated favorable in vitro floating and release characteristics. The release pattern of optimized, secondary-coated granules of orlistat in simulated gastrointestinal fluids corresponded best to the Peppas-Korsmeyer model and Higuchi matrix model. The results clearly indicated the controlled and sustained release of orlistat from its gastro-retentive floating granular delivery system.