ABSTRACT:
Oral route has been the most suitable and accepted route of drug delivery. But oral control release dosage forms face several physiological restrictions like inability to retain and locate the controlled drug delivery system within the targeted region of the gastrointestinal tract (GIT) due to fluctuation in gastric emptying. This results in non-uniform absorption pattern, inadequate medication release and shorter residence time of the dosage form in the stomach. Gastro retentive drug delivery system (GRDDS) is novel drug delivery systems which are more advantages due to its ability of prolonged retaining ability in the stomach and thereby increase gastric residence time of drugs and also increase bioavailability of drugs. This present review covers the advantages, disadvantages, factors affecting on GRDDS, Recent approaches, floating and non-floating drug delivery system and also highlights the other effective approaches who increases gastric residence time of drug such as bio-adhesive systems, floating systems (low density systems), non-floating systems (high density systems) , floating muco-adhesive drug delivery system, magnetic systems, swelling systems, un-foldable and expandable systems, raft forming systems and super porous systems, biodegradable hydro-gel systems. Marketed preparation and some patents of gastro-retentive drug delivery system, excipient used in formulation of GRDDS, recent work done on GRDDS.