RESUMEN
Much attention have been focused in pharmaceutical research in the area of gastroretensive oral drug delivery systems. Henceforth a wide spectrum of dosage forms have been developed for drugs which are unstable in alkaline pH, soluble in acidic pH, having a narrow absorption window, site of action specific to stomach. This article provides the entire classification of gastroretensive systems, formulation considerations for developing gastroretensive systems, factors affecting gastroretensive systems, merits and demerits, applications in pharmacy and a comparative diagrammatic representation limelight this article. Those gastroretensive systems which depend on liberation of carbondioxide show poor patient compliance because of flatulence and belching.