pH Responsive 5-Fluorouracil Loaded Biocompatible Nanogels For Topical Chemotherapy of Aggressive Melanoma

Combating melanoma via topical route is a highly challenging task due to low selectivity, poor efficacy and impeding biological environment of the skin. In the present study, we engineered a chitosan based pH responsive biodegradable nanogel (FCNGL), encapsulated with 5-FU that was effective even at very low drug doses (0.2% w/v) against melanoma. The FCNGL was synthesized by ion gelation technique exhibited nano-size particle distribution and sustained drug release kinetics. Hemolysis and coagulation analysis revealed high safety whereas MTT and apoptosis assays exhibited the efficacy of FCNGL. DMBA-Croton oil Swiss albino mice model was employed for in vivo assessment followed by gamma scintigraphic screening. Tumor burden and pharmacokinetic antioxidant stress levels along with whole-body gamma scintigraphy imaging using 99 mTc labelled nanogel exhibited selective accumulation in melanoma tumor nodules. The pH responsive behaviour of the nanogels resulted in triggered release of 5-FU in slightly acidic microenvironment, resulting in selective drug accumulation at the melanoma site. Immunohistochemistry (IHC) analysis of tumor showed improvement of subcutaneous layer alignment and regeneration of the epithelial skin layer when compared with standard 5% 5-FU and control mice group. Overall our preclinical data using the FCNGL portends to be a promising platform for efficient and sustained delivery of 5-FU for topical chemotherapy that can result in high efficacy, patient compliance and safety in the clinical set up.