Recently controlled and sustained drug delivery has become the new standard in modern pharmaceutical design and a thorough research has been undertaken in achieving much better drug product effectiveness, reliability and safety. In situ gelling system has become an outstanding among novel drug delivery system (NDDS) in recent years due to its advantages like sustained and prolonged drug action, improved patient compliance and reduced frequency of administration of the drug compared to conventional drug delivery system (DDS). In this system the formulation is in the form of solution and when comes in contact with body fluids it undergoes gelation to form a gel. The formation of gels depends on factors like temperature changes, pH changes, presence of ions and ultraviolet irradiation. Various biodegradable polymers like gellan gum, pectin, alginic acid, chitosan, xyloglucan, etc are used. In situ gels are administered through various routes like oral, ocular, nasal, rectal, vaginal, injectable and intraperitonial. The production of such devices is also less complex and thus lowers the investment and manufacturing cost.

Keywords: NDDS, Gelling systems, Gelation, excipient