ABSTRACT
The basic tenet in the design of oral controlled-release drug delivery systems is that the kinetics of drug release, rather than the kinetics of drug absorption, controls the availability of the drug. The developments in pharmaceutical dosage form design have been outlined to enable students to see the progressive nature of the efforts on delivery of bioactive agents. The first generation drug delivery systems appeared toward the end of the nineteenth century and in the twentieth century, and they have consistency and uniformity. In the second generation drug delivery systems, repetitive, intermittent dosing of a drug occurs from one or more immediate release units incorporated into a single dosage form. The design of the vast majority of the third generation drug delivery systems involves the use of polymers. Drug targeting increases the therapeutic potential and reduces side effects of the drug.
