In vitro and in vivo anti-tumor efficiency comparison of phosphorylcholine micelles with PEG micelles.

Polymer micelles for anticancer drug delivery have shown many advantages. In this study, poly(ε-caprolactone)-b-poly(2-methacryloyloxyethyl phosphorylcholine) (PCL-PMPC) with bio-inspired structure self-assembled into small and uniform micelles as traditional poly(ε-caprolactone)-b-poly(ethylene glycol) (PCL-PEG). The in vitro and in vivo anti-tumor efficiency of PCL-PMPC and PCL-PEG micelles were detailedly evaluated. The both micelles were able to load DOX with high efficiency. PCL-PMPC micelles exhibited faster drug release at pH 5.5 than that of PCL-PEG micelles. Confocal laser scanning microscopy and flow cytometry results showed that PCL-PMPC micelles were more effectively internalized by tumor cells. DOX-loaded PCL-PMPC micelles presented higher cytotoxicity to tumor cells. PCL-PMPC micelles displayed not only longer circulation time in pharmacokinetics investigation, but also higher accumulation at the tumor site in in vivo imaging study in comparison with PCL-PEG micelles. More importantly, in a tumor model DOX-loaded PCL-PMPC micelles showed better therapeutic efficacy than DOX-loaded PCL-PEG micelles along with mild side effects. Therefore, PCL-PMPC micelles are deemed to be promising drug carriers for cancer therapy.