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
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.