An approach to controlled-release dosage form of propranolol hydrochloride.

It is possible to release a drug with only limited diffusion from a membrane-coated system using osmotic pumping. In this study, a propranolol osmotic pump was produced by coating the core tablets with cellulose acetate. The effects of membrane thickness, pore size, and stirring rate on the release rate of propranolol hydrochloride were studied. It was found that the thickness of cellulose acetate membrane had a profound effect on the release rate of propranolol hydrochloride from the membrane-coated tablets. The results showed that, when the membrane thickness increased, the release rate of propranolol decreased. The drug release follows a zero-order release when the delivery orifice is between 200 and 800 microns, but when the delivery orifice size is increased to 1000 microns, the release kinetic is abnormal. Fluid dynamics have an important effect on the delivery rate of propranolol from this device; the delivery rate increases as a function of the fluid flow. The drug release is higher under a turbulent condition with high rate of stirring.