Construction of polymer-paclitaxel conjugate linked via a disulfide bond

Covalently linked amphiphilic polymer-paclitaxel (PTX) could self-assemble into micelles to overcome many drawbacks of existing delivery systems of PTX by virtue of tunable compositions, variable sizes, high drug loading content and zero burst release. Moreover, a reduction-responsive system based on glutathione (GSH) can be established by introducing disulfide bonds into the polymeric carriers to improve the selectivity for cancer cells. Herein, we reported a disulfide bond linked polymer-PTX, P(PEGMEA)-co-P(PDPHEMA)-g-PTX with a high PTX loading content of 43.7 wt.%. In vitro cell assay showed that the polymer carrier has almost no cytotoxicity. The half maximal inhibitory concentration (IC50) values of the polymer-PTX conjugate against HEK-293 cells was about 10 times higher than that of HeLa cells after incubation for 72 h. Such a dramatic selectivity for cancer and normal cells provides a promising strategy to improve the therapeutic efficacy and decrease the side effects of PTX in chemotherapy.