Attempts are made in research and development of sustained and controlled drug delivery systems to overcome physiological and unpredictable gastric empting time (GET). Such dosage forms are useful for the drugs with ‘narrow therapeutic index'. Formation of gel depends on factors such as temperature, pH, ionic cross linking and UV irradiation, from which drug is released in controlled or sustained manner. In-situ gelling systems is prominent among other novel drug delivery systems (NDDS), due to advantages such as sustained and prolonged drug action, improved patient compliance and reduced frequency of drug administration as compared to conventional drug delivery system. These polymeric formulations are in solution form before administration and then turns to gel form when comes in contact with gastric fluids. Various natural, biodegradable, biocompatible and water soluble polymers such as pectin, gallen gum, chitosan, poly-caprolactone, xyloglucane, poly-D, L-lactic acid, pluronic F 127, carbopol, etc makes this drug delivery most acceptable and useful. In-situ gel is fabricated for both local and systemic drug delivery at specific site of action. Various evaluations are recommended for in-situ gels mostly viscosity, buoyancy, gelling capacity and dissolution studies are performed. This review presents current trends in fabrication, evaluation parameters and importance of various drugs formulated as in-situ gelling system
