Bashir et al Journal of Drug Delivery & Therapeutics. 2019; 9(2):442-448 ISSN: 2250-1177 [442] CODEN (USA): JDDTAO Available online on 15.03.2019 at http://jddtonline.info Journal of Drug Delivery and Therapeutics Open Access to Pharmaceutical and Medical Research © 2011-18, publisher and licensee JDDT, This is an Open Access article which permits unrestricted non-commercial use, provided the original work is properly cited Open Access Review Article Floating Oral In-Situ Gel: A Review Rabiah Bashir, Asmat Majeed, Tabasum Ali, Saeema Farooq, Nisar Ahmad Khan* Department of Pharmaceutical Sciences, School of Applied Sciences and Technology, University of Kashmir, Hazratbal, Srinagar, 190006, Jammu and Kashmir, India. ABSTRACT The drugs having a narrow absorption window in the gastrointestinal tract (GIT) when administered by oral route are often limited by poor bioavailability due to incomplete drug release and short residence time at the site of absorption. Novel drug delivery systems in the form of gastroretentive systems such as floating systems, mucoadhesive, high-density, expandable have been developed as they provide controlled delivery of drugs with prolonged gastric residence time. Liquid orals are more prone to low bioavailability because they are eliminated quickly from the stomach since they are subjected to faster transit from the stomach/ duodenum. The problems of immediate release and short gastrointestinal residence of liquids are eliminated by formulating as oral in situ gels as they provide the best means to overcome these problems The in situ gel dosage form is a liquid before administration and after it comes in contact with gastric contents due to one or more mechanisms gets converted to gel which floats on gastric contents. This achieves increased residence as well as sustained release. This approach is useful for systemic as well as local effect of drugs administered. This review gives a brief idea about floating oral in-situ gel formation and research done by various scientists on a number of drugs and polymers. Keywords: Floating drug delivery, gastric retention time, In-situ gel. Article Info: Received 24 Jan 2019; Review Completed 20 Feb 2019; Accepted 22 Feb 2019; Available online 15 March 2019 Cite this article as: Bashir R, Majeed A, Ali T, Farooq S, Khan NA, Floating Oral In-Situ Gel: A Review, Journal of Drug Delivery and Therapeutics. 2019; 9(2):442-448 http://dx.doi.org/10.22270/jddt.v9i2.2372 *Address for Correspondence: Nisar Ahmad Khan, Department of Pharmaceutical Sciences, University of Kashmir, Hazratbal, Srinagar-190006, Jammu and Kashmir, India. INTRODUCTION Floating Drug Delivery System is one of the novel system of drug delivery. Various dosage forms are formulated in the form gastro retentive floating systems such as microspheres, micro beads, tablets, capsules, films etc. In-situ gelling system is a new trend in floating DDS. In-situ gelling system have its application in different routes of administration like oral, nasal, ophthalmic, peroral, rectal, vaginal and also parenteral route. In situ forming polymeric drug delivery systems has many advantages such as ease of administration, increased local bioavailability, reduced dose frequency, improved patient compliance and has less complex method of production and so is cost effective. Gastro retentive FDDS have bulk density lower than gastric fluid and hence remain buoyant in stomach without affecting the gastric emptying rate for a long period of time. When the gel so formed float on gastric fluid the drug get released slowly at desired rate from the floating gel. After drug is released from floating system, the residual part is emptied from stomach. This may increase GRT and also control the fluctuations in plasma drug concentration (PCD). Floating system are the controlled or sustained release dosage form and have properties similar to hydrophilic matrices and so called as hydrodynamically balanced system (HBS) as they form a low density polymeric gel barrier at outer surface. Drug is slowly released from the matrices same as that in case of conventional hydrophilic matrices. This form may remain buoyant (8-10 hours) on gastric contents without affecting the rate of gastric emptying. Different polymer systems are used in floating drug delivering dosage forms. Among those some are polysaccharides, polymethacrylates, hydrocolloids etc. in this cellulose ether polymers are most popular, especially HPMC. The formulation of floating in situ gelling solution may sustain and prolong drug action, improve patient compliance and reduce frequency of administration of the drug in comparison to conventional drug delivery system 1-9 . Floating drug delivery system (FDDS) was first described by Davis in 1968. FDDS is an effective technology to prolong the gastric residence time in order to improve the bioavailability of the drug. Floating drug delivery systems meant for gastric retention, float on the surface of the gastric fluids, due to their low density and produce prolonged effect by showing the controlled release. This type of delivery system is of great value for drugs which get absorbed from upper part of the stomach i.e. their absorption window resides in upper part of stomach. It is also useful for drugs which are inserting at alkaline pH of intestine and remains unabsorbed or causes side effects due to insolubility. The FDDS are particularly