ABSTRACT
Controlled-release matrix tablets have become the simplest and least expensive method to control drug release. During the past two decades, many polymers, waxes, gums, and clays have been reported in the literature as retardant materials in this system (1-7). The retardant materials have been introduced into the formulation, using direct compression, wet granulation, and recompression techniques. The majority of controlled delivery systems for the oral route release the active agent into the gastrointestinal juices by dissolution, diffusion, or a combination of both mechanisms. The selection of both drug and retardant polymers along with the other filler excipients will impact the mechanism and rates of drug release from monolithic systems.
