Studies on In-Situ forming thermo sensitive injectable polymeric gel for sustained drug delivery

Abstract

The in situ injectable gel is a polymeric formulation which provides several advantages when compared to conventional injectable drug delivery systems. These types of formulations are actually prepared by smart polymers i.e. that change its microstructure according to environmental change. These polymers remain in sol form before administration into the body, but once administered, undergo gelation in situ, to form a gel. Thus the in situ forming polymeric formulations are dependent on biodegradable smart polymers. The formation of gel or gelation occur for many reasons depending on factors like temperature modulation, electrical sensitivity, pH change, presence of ions, ultra violet irradiation and enzyme sensitive from which the drug gets released in a predetermined or controlled manner. Thus this article presents a detailed review of these types of polymeric formulation composed of thermo responsive polymers. Heat sensitive or thermo responsive polymers are those which have a discontinuous change of their physical properties with temperature modulation and thus undergo physical change inside the human body. The production and the formulation system is a very simple and low cost where various synthetic as well as natural thermo sensitive polymers are used for the formulation of in situ gel. The in situ gel dosage form having good stability, biocompatibility and increasing patient compliance makes more reliable and acceptable drug delivery system.