An Insight to In-Situ Gel Forming Stomach Specific Drug Delivery System

The oral delivery of drugs having narrow absorption window in the gastro-intestinal tract is limited by poor bioavailability with conventional dosage forms due to incomplete drug release and short residence time at the time of absorption. To provide controlled delivery of drugs novel drug delivery systems have been developed. Different systems have been developed to increase the gastric residence time viz. floating system, mucoadhesive, high density, expandable. Among all oral dosage forms, liquid orals are more prone to low bioavailability due to fast transit time from stomach to duodenum. Sustained/Controlled delivery can be achieved by decrease in the transit time of the dosage form. This can be augmented by an approach of liquid in-situ gelling system. These in-situ formulations are the drug delivery systems that are in sol form before administration in the body, but when administered, undergo gelation, in-situ, to form a gel. Formation of gel depends on various factors viz. temperature modulation, pH change, presence of ions, ultra-violet irradiation, from which drug releases in a sustained and controlled fashion. Different polymers which can be used for formation of in-situ gel include gellan gum, alginic acid, xyloglucan, pectin, chitosan, poly-caprolactone, poly-lactic acid, polylactic-co-glycolide. This article presents a detailed review of introduction, approaches to achieve in situ gelling system, polymers used, evaluation parameters, advantages of in situ gelling system.