Abstract: 
Orally administered drugs having poor Absorption window in the proximal gut can limit the bioavailability. Gastro-retention is one of the approaches to retain drug in GI tract for several hours gives prolong residence time and drug release. GRDDS is helps to improve bioavailability and polymer concentration gives sustained drug delivery. Gastro-retentive 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. Recently oral controlled release drug delivery has been of great interest in pharmaceutical field to achieve improved therapeutic advantages. In recent years, gastro-retentive drug delivery has gained abundant importance for medicine acting regionally within the proximal a part of digestive tract. Various approaches such as floating and non-floating system. GRDDS which are further classified are cited in this review. This article gives an overview on advantages & disadvantages of gastro-retentive drug delivery systems.

Keywords: Gastro-retentive, GRDDS, Floating, Bioadhesion, Hydrodynamically balanced system, Effervescence.