Vitamin E-based micelles enhance the anticancer activity of doxorubicin

The purpose of this study was to develop vitamin E-based micelles loaded with Doxorubicin (DOX) (DOX-TOS-TPGS), taking advantages of the anti-cancer activity of vitamin E derivatives: Tocopherol succinate (TOS) and D-α-tocopherol polyethylene2000 succinate (TPGS). Therefore, we developed micelles consisting in a mixture of TOS (as solubilizer) and TPGS2000 (as stabilizer) (1:1). DOX-TOS-TPGS micelles exhibited a size of 78 nm and a ζ potential of -7 mV. High drug loading (40% w/w) was achieved. The critical micellar concentration was determined at 14 μg/ml. In vitro, after 24 h, DOX-TOS-TPGS micelles exhibited higher cytotoxicity than free-DOX (IC50 on MCF-7 cells, at 24 h, 58 vs 5 μg/ml). In vivo anti-tumor efficacy, performed on two tumor models (CT26 and MCF-7), demonstrated a 100% long-term survival of mice when treated with DOX-TOS-TPGS compared to DOX-free. Interestingly, the survival time of mice treated with unloaded TOS-TPGS micelles was similar to DOX-free, indicating an anti-cancer activity of vitamin E derivatives. Based on these results, it can be concluded that the formulations developed in this work may be considered as an effective DOX delivery system for cancer chemotherapy.