DEVELOPMENT AND EVALUATION OF NEFOPAM HYDROCHLORIDE MICROCAPSULES

An attempt was performed to encapsulate Nefopam hydrochloride, a highly water soluble drug, by a modified emulsion solvent evaporation / extraction technique, using cellulose acetate butyrate (CAB) as a coating polymer. The influence of core/coat ratio (1:2, 1:1 and 2:1 ratio) on the yield, drug loading, size distribution as well as the release characteristics and surface topography of the prepared microcapsules was investigated. The obtained microcapsules exhibited higher encapsulation efficiency and a decreased release rate in simulated gastric fluid (S.G.F. pH 1.2) and simulated intestinal fluid (S.I.F. pH 7.4). On the other hand, the entrapment efficiencies increased (from 104.66 to 141.26, core coat ratio 1:1) and the release rate decreased with increasing microcapsule size (from 250 to 512.5 µm) and/or theoretical drug loading of microcapsules. Kinetic assessment of the release rate of microcapsules using different mathematical models has shown that the release rate followed Ritger-Peppas diffusion release kinetics