Bentonite nanoclay-based drug-delivery systems for treating melanoma

Local chemotherapy with biocompatible drug-delivery systems prolongs survival in patients. Due to the biocompatibility and high loading capacity, bentonite nanoclay is a good candidate for the fabrication of drug-delivery vehicles. In this study, doxorubicin-bentonite nanoclay complex (DOX-Bent complex) was prepared for the first time as a sustained-release drug-delivery system for intratumoural chemotherapy of melanoma. An efficient loading of DOX on 1 mg of bentonite nanoclay as high as 994.45 +/- 4.9 mu g was obtained at a 30:1 DOX:bentonite nanoclay mass ratio. The DOX-Bent complex showed a low initial burst release of DOX in the first 24 h of release, followed by a sustained-release pattern for 21 days. The cumulative in vitro release of DOX from the DOX-Bent complex at pHs 6.5 and 7.4 revealed that the DOX-Bent complex can distinguish between tumour and normal tissues and express specific drug release at the tumour site. The results of cytotoxicity experiments indicated that the release pattern of DOX can supply sufficient DOX to inhibit growth of the melanoma cancer cell with an IC50 of 0.29 + 0.07 mu g/mL. It is thus suggested that the DOX-Bent complex be introduced as a drug-delivery system for effective local cancer therapy.