Redox poly(ethylene glycol)-b-poly(L-lactide) micelles containing diselenide bonds for effective drug delivery.

Bioreducible polymers have appeared as the ideal drug carriers for tumor therapy due to their properties of high stability in extracellular circulation and rapid drug release in intracellular reducing environment. Recently, the diselenide bond has emerged as a new reduction-sensitive linkage. In this work, the amphiphilic poly(ethylene glycol)-b-poly(L-lactide) containing diselenide bond has been synthesized and used to load anti-tumor drug, docetaxel (DTX), to form the redox micelles. It was found that the redox micelles showed a rapid response to glutataione (GSH), which resulted in a fast release of DTX in the presence of GSH. In contrast, <40 % of DTX was released from the micelles within 72 h under the normal condition (absence of GSH). The DTX-loaded redox micelles showed the significant inhibition effect to MCF-7 cells, and the cytotoxicity was dependent on the intracellular GSH concentrations. Moreover, considering the potentially clinical applications of the micelles through intravenous injection, the blood compatibility was also studied by the hemolysis analysis, activated partial thromboplastin time, prothrombin time and thromboelastography assays. These results confirmed that the redox micelles showed good blood safety, suggesting a potential application in tumor therapy.