Gastro Retentive Drug Delivery Systems: A Review

Gastric emptying is a complex and extremely variable process. This causes the unpredictability of the bioavailability of drug delivery systems. Gastro retentive drug delivery systems (GRDDS)s have received significant attention in the past decades primarily due to the fact that they can overcome the limitation of conventional oral controlled release drug delivery systems related to fast gastric emptying time. An optimum GRDDS can be defined as a system which remains in the stomach for a sufficient time interval 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 pharmacotherapy. This article gives an overview of the main concepts used to design pharmaceutical dosage forms with prolonged gastric residence times as well as the parameters-affecting gastric emptying, advantages, shortcomings, formulation considerations and, factors that affect gastro retentive systems. The main emphasis is on the entire classification and different types of GRDDSs. Finally evaluation methods of these systems have been summarized.