RELEASE MECHANISMS IN GELFORMING SUSTAINED-RELEASE PREPARATIONS

A system consisting of quinidine sulfate, excipient and gum (in various concentrations) was tested in tablet form. The insensitivity of this system to (a) the nature of the excipient and (b) the pH of the dissolution liquid is noted. The release mechanism is established as being limited by the rate of water penetration and back diffusion of the dissolved substance, whereas gelation rates and actual dissolution rate of the drug are not rate determining. © 1979.