Long-acting drug delivery systems (DDSs) have attracted interests for tumor chemotherapy. Here, novel reduction-triggered polymer prodrug was designed by conjugation of a high-performance thiolated doxorubicin (DOX-SH) onto the diblock copolymer PEG₄₃-PPDSM₄₃ via the bioreducible cleavable disulfide bond. The resultant polymer prodrug PEG₄₃-PPDSM₄₃-DOX with a DOX content of 33 % could be easily self-assembled into nanoparticles of 146 nm. They showed a slow solubility-controlled sustained drug release with a cumulative release of 30.13 % within 84 h in the simulated tumor intracellular microenvironment but an ultra-low premature drug leakage of 4.01 % in the simulated normal physiological media. Such slow sustained release is expected to prolong the action time of the active drug. The MTT assays demonstrated the tumor-selective killing performance of the proposed prodrug nanoparticles with an enhanced antitumor efficacy on the tumor HepG2 cells than the free DOX, but no obvious cytotoxicity on the normal L20 cells at the lower dosages.

长效药物递送系统（DDS）已经引起了肿瘤化疗的兴趣。在这里，通过生物可还原的可切割二硫键将高性能硫醇化多柔比星 (DOX-SH) 缀合到二嵌段共聚物 PEG ₄₃ -PPDSM ₄₃ 上，设计了新型还原触发聚合物前药。所得聚合物前药 PEG ₄₃ -PPDSM ₄₃-DOX 含量为 33% 的 DOX 可以很容易地自组装成 146 nm 的纳米颗粒。他们在模拟的肿瘤细胞内微环境中表现出缓慢的溶解度控制的持续药物释放，在 84 小时内累积释放 30.13%，但在模拟的正常生理介质中的超低过早药物泄漏率为 4.01%。这种缓慢的持续释放有望延长活性药物的作用时间。MTT测定证明了所提出的前药纳米颗粒的肿瘤选择性杀伤性能，与游离DOX相比，对肿瘤HepG2细胞的抗肿瘤功效增强，但在较低剂量下对正常L20细胞没有明显的细胞毒性。