Polyprodrugs for tumor chemotherapy: from molecular structure to drug release performance.

Polyprodrugs have been recognized as promising carrier-free drug delivery systems (DDSs) for tumor chemotherapy in recent years, showing distinct superiority in comparison with the conventional polymer prodrugs. In the present work, the structure-property relationship of polyprodrugs was explored from the perspective of molecular structure, by discussing the effects of the conjugations and linkers on their drug content and drug releasing performance, including drug releasing rate and drug releasing selectivity, as well as the anti-tumor performance of the released drugs. Moreover, the future challenges in the design of polyprodrug-based DDSs with high anti-tumor efficacy were also highlighted.