An Overview on Various Approaches and Recent Patents on Gastroretentive Drug Delivery Systems.

Background: Drugs having absorption window in the stomach or upper small intestine have restricted bioavailability with conventional dosage forms. The gastric residence time of these dosage forms is usually short and they do not show drug release for prolonged period of time.

Objective: To avoid these problems and to enhance the bioavailability and gastric retention time of these drugs, controlled drug delivery systems with prolonged gastric retention time are currently being developed.

Methods: This review highlights the various pharmaceutical approaches for gastroretention such as floating drug delivery systems, mucoadhesive systems, high-density systems, expandable and swelling systems, super porous hydrogels systems, magnetic systems, ion exchange resin system and recent patents filed or granted for these approaches.

Results: Recently, some patents are also reported where a combination of various approaches is being employed to achieve very effective gastroretention. The various patent search sites were used to collect and analyze the information on gastroretentive drug delivery systems.

Conclusion: The present study provides valuable information, advantages, limitations and future outlook of various gastroretentive drug delivery systems.