Doxorubicin-loaded micelles with high drug-loading capacity and stability based on zwitterionic oligopeptides

Abstract

To simplify the preparation process and increase the drug-loading capacity of antitumor nanodrugs, doxorubicin-loaded micelles based on zwitterionic oligopeptides were fabricated through two step reactions in mild conditions. Zwitterionic oligopeptides Glu–Lys–Cys–Glu–Lys (EKCEK) were reacted with methacrylohydrazide (MAH) by click reaction, the product was further conjugated with doxorubicin (Dox) to form amphipathic molecules, and finally the amphipathic molecules self-assembled into doxorubicin-loaded micelles (EKCEK–Dox) in deionized water. TEM and DLS results showed that the EKCEK–Dox micelles were of the regular sphere, with the mean diameter approximately 70 nm. The drug-loading capacity of the prepared micelles was up to 44.6%, and the micelles were very stable in PBS solution. In vitro antitumor experiment showed that the EKCEK–Dox micelles had significant inhibition efficacy on MCF-7 cells, which was much better than the clinical antitumor drug (Doxil®). The IC50 of the EKCEK–Dox micelles (5.6 μg Dox equiv. per mL) was significantly lower than Doxil (8.9 μg Dox equiv. per mL). Therefore, the drug delivery system based on zwitterionic oligopeptides will be a promising strategy for cancer chemotherapy.