In Situ Gels Based Drug Delivery Systems

In the past few years, an increasing number of in situ gel forming systems have been reported in the literature for various biomedical applications, including drug delivery, cell encapsulation, and tissue repair. The possible mechanisms that lead to in situ gel formation are solvent removal, ionic cross-linkage, light-sensitive, pH change and temperature modulation. The ability to inject a drug incorporated into a polymer to a localized site and have the drug from a semi-solid depot has a number of advantages. The advantages include ease of application, localized and prolonged drug delivery. For these reasons a large number of in situ setting polymeric delivery systems have been developed and investigated. This article reviews the stimuli-sensitive polymers and the use of these polymers in parenterals, ocular, peroral, rectal, vagina, nasal, dermal and transdermal drug delivery.