Abstract
Microcapsules are designed to obtain sustained release of naproxen. Investigations were conducted to evaluate the influence of the nature of core on the release of naproxen from ethyl cellulose microcapsules. Emulsification and solvent evaporation approach is employed to prepare the ethyl cellulose microcapsule of naproxen. When pure drug naproxen as such is employed to prepare the microcapsules – it resulted in very slow release in the first 2 hours in simulated gastric fluid and latter release was faster in the simulated intestinal fluid. This could be because of the difference in dissolution of the drug in the different fluids. But when naproxen gelucire dispersions were employed the release could be better controlled and was spread over a period of 12 hours. Two different types of gelucire are employed – gelucire (50/13) and gelucire (43/01). Solid dispersion of naproxen in gelucire (50/13) and gelucire (43/01) resulted in fast dissolving and slow dissolving forms of naproxen respectively. The various microcapsules were characterized with respect to drug polymer interaction, surface nature and drug release. The various microcapsules were found to be spherical and free flowing. The release was dependent on the nature of gelucire employed and the per cent coat of ethyl cellulose in the microcapsules. The release was found to follow first order kinetics and is diffusion controlled. It can be concluded from the results that release of naproxen from microcapsules can be modified by suitably altering the nature of naproxen that is incorporated as core in the microcapsules.