Injectable hydrogel based on quaternized chitosan, gelatin and dopamine as localized drug delivery system to treat Parkinson's disease.

There is still an enormous demand for designing materials to the treatment of Parkinson's disease, and dopamine-based injectable polysaccharide hydrogels as localized drug delivery system have huge potential. Here, we developed a facile approach to prepare dopamine-based and polydopamine crosslinked injectable hydrogels by simply oxidizing a mixture of quaternized chitosan, gelatin and dopamine under physiological conditions. These injectable hydrogels showed stable mechanical strength by rheometer and exhibited good degradability evaluated by in vitro degradation test. The chemical structure and morphology of the hydrogels were characterized by FT-IR and SEM. Dopamine as a drug for treating Parkinson's disease and metronidazole as an anti-inflammatory drug were encapsulated in the hydrogel. The release profiles indicated that the injectable hydrogels have great capacity as a carrier for long-term localized release system for dopamine and metronidazole. Furthermore, the cytocompatibility of the hydrogels was confirmed by cell viability and proliferation assays using mouse L929 fibroblast cells. This work provides a new and facile approach to prepare dopamine-based injectable materials which can be used as long-term injectable sustained release system for dopamine as well as anti-inflammatory drug for Parkinson's treatment.