Injectable chitosan hydrogels for localised cancer therapy.

The pace of development of delivery systems that could target drugs to specific body sites and control the release of drugs for prolonged periods of time have been steady though slow. Till a decade ago, mostly microspheres or nanoparticles were widely studied and applied in cancer treatment. However, due to shortcomings of these systems, there has been a surge in interest for in situ hydrogels. This review focuses on the current use of injectable in situ chitosan hydrogels in cancer treatment. Formulation protocols for in situ hydrogel systems, their cytotoxic properties, loading and in vitro release of drugs, their effect on cell growth in vitro and inhibition of tumor growth in vivo using mouse models, and future directions to enhance this technology are discussed.