In recent years, gastroretentive drug delivery system (GRDDS) has gained researcher’s interest in the field of oral drug delivery. Various GRDDS approaches can be utilized to retain the dosage forms in the stomach and to release the drug slowly for an extended period of time. GRDDS can be used to prolong the residence time of delivery system in the stomach. This results in targeting of drug release at a specific site for the systemic or local effects. GRDDS can be used to overcome challenges associated with conventional oral dosage forms and to release the drug at a specific absorption site to improve bioavailability of particular drug substance. The challenges include fast gastric emptying of the dosage form which results in the poor bioavailability of the drug. Prolongation of the retention of drugs in stomach those having low solubility at high intestinal pH improves the solubility of drugs. GRDDS has proved to be effective in systemic actions as well as in local actions to treat gastric or duodenal ulcers. Local activity in the upper part of the small intestine can be obtained by improving the residence time of delivery system in the stomach. The system is useful for drugs which are unstable in the intestine or having a low solubility/permeability in the small intestine. Various GRDDS approaches include high density (sinking) systems, low-density (floating systems), mucoadhesive, expandable, unfoldable, superporous hydrogel systems, and magnetic systems
