Biodegradable polyurethane PMeOx-PU(SS)-PMeOx micelles with redox and pH-sensitivity for efficient delivery of doxorubicin

Abstract In this paper, a new amphiphilic block polymer of polyoxazoline-polyurethane (PMeOx-PU(SS)-PMeOx) was prepared by introducing disulfide bonds into the polyurethane backbone and capping with polyoxazoline. This block polymer can be self-assembled in water to form polymer micelles with particle size of 163.1±0.5 nm. Using the antitumor drug doxorubicin (DOX) as a model drug, the drug release behaviour of drug-loaded micelles in a simulated intracellular environment was studied. The results indicated that the release of the drug can be stimulated in an acidic and reductive environment. The MTT test showed that the DOX-loaded PMeOx-PU(SS)-PMeOx micelles had high activity against C6 (rat glioma cells) cells, and the half-maximal inhibitory concentration (IC50) was 10.14 μg/mL. These results indicated that pH and reductiondual-responsive PMeOx-PU(SS)-PMeOx DOX-loaded micelles have broad application prospects in the efficient release of intracellular hydrophobic anticancer drugs (98.21%) and in improving the therapeutic effect of cancer.