ABSTRACT
Controlled-release drug delivery design involves the application of physical and polymer chemistry to dosage-form design to produce a well-characterized and reproducible dosage form that controls drug entry into the body within the specifications of the required drug delivery profile. The controlled-release dosage form should be tailored so that variations in component characteristics lead to predictable alterations in release profiles. Controlled-release drug delivery currently involves control of either the time course or location of drug delivery. Delivery rates from temporal controlled-release systems may be characterized in terms of their kinetics and physical processes. With zero-order delivery, it may be important to select plasma levels that avoid adverse drug reactions. The justification for a controlled-release dosage form over a conventional tablet is either to optimize therapy or to circumvent problems in drug absorption or metabolism. Without this therapeutic rationale, a controlled-release dosage form would be unlikely to succeed as a product.
