Gastroretentive Drug Delivery Systems: A Review of Formulation Approaches

Gastroretentive dosage forms (GRDF) has received significant interest in the past few decades as they can improve the limitation of most conventional and oral controlled release drug delivery system related to fast gastric-emptying time. An optimum GRDF system can be defined as a system which retains in the stomach for a sufficient time interval against all the physiological barriers, releases active moiety in a controlled manner. This article gives an overview of the parameters affecting gastric emptying as well as on the main concepts used to design pharmaceutical dosage forms with prolonged gastric residence times. In particular, bioadhesive, size-increasing and floating drug delivery systems are presented and their major advantages and shortcomings are discussed. Both single and multiple unit dosage forms with dual working systems are reviewed. Dual working systems are more efficient than the traditional systems. Keyword: Gastroretentive Dosage Forms, Gastrointestinal Tract, Bioadhesive Systems, Unfolding Systems, Density Controlled Systems