124ANTI ULCER ACTIVITY OF NIZATIDINE HYDROCHLORIDE LOADED FLOATING MICROSPHERES BASED DRUG DELIVERY SYSTEMGastro-retentive drug delivery system (GRDDS) has gained immense popularity in the field of oral drug delivery recently. It is a widely employed approach to retain the dosage form in the stomach for an extended period of time and release the drug slowly that can address many challenges associated with conventional oral delivery, including poor bioavailability. The main limitations are attributed to the inter- and intra-subject variability of gastro-intestinal (GI) transit time and to the non-uniformity of drug absorption throughout the alimentary canal. It is known that differences in gastric physiology, such as gastric pH, and motility exhibit both intra-as well as inter-subject variability demonstrating significant impact on gastric retention time and drug delivery behavior. This triggered the attention towards formulation of stomach specific (gastro retentive) dosage forms. Floating or hydro dynamically controlled drug delivery systems are useful in such applications. The drugs having absorption window in the upper part of Gastro Intestinal Tract (GIT) have enhanced bioavailability when formulated through these techniques. The recent technological development for enhancing GRT including the physiological and formulation variables affecting gastric retention. The developed system has the dual advantages of being gastro-retentive, to increase oral bioavailability and releasing drug in a controlled manner.mishrasanjay328@gmail.comResearch912019Floating drug delivery systems,Gastric residence time,in vitro and in vivoSanjay K. Mishra,M.K GuptaOriental College of Pharmacy and Research, Oriental University Indore, Madhya Pradesh, India,Oriental College of Pharmacy and Research, Oriental University Indore, Madhya Pradesh, India