Abstract

Gastro retentive drug delivery system (GRDDS) can be defined as a system which remains in the stomach for
a sufficient time period and releases active ingredients in a controlled manner. This, significantly extends
the duration of drug release, prolongs dosing interval and increases bioavailability of drugs and therefore
improves compliance of the patients and effectiveness of pharma cotherapy. The current review deals with the
advantages, disadvantages, parameters-affecting gastric emptying, formulation considerations, factors that affect
gastro retentive systems and also highlights some of the recent gastro retentive approaches. Recent approaches to
increase the gastric residence time of drug delivery systems include bio adhesive systems, floating systems (low
density systems), non-floating systems (high density systems) , magnetic systems, swelling systems, un foldable and
expandable systems, raft forming systems and superporous systems, biodegradable hydro gel systems. The main
emphasis is on the entire classification and different types of GRDDS. Finally evaluation methods of these
systems have been summarized.

Key words: GRDDS, Bioavailability, Gastric emptying, Superporous