Poly(D,L‐lactide‐co‐glycolide)‐poly(ethylene glycol) (PLGA‐PEG) diblock copolymers with different compositions were synthesized by ring‐opening polymerization of D,L‐lactide and glycolide, using monomethoxy PEG as macro‐initiator. The resulting copolymers were characterized by nuclear magnetic resonance, gel permeation chromatography, and critical micelle concentration analyses. Self‐assembly of the copolymers yielded aggregates of different architectures, including spherical micelles and a mixture of spherical and worm‐like micelles with Y‐junctions. The self‐assembled architecture depends on both the hydrophilic/hydrophobic balance and the molar mass of copolymers. Valsartan, a widely used drug in the treatment of hypertension, was loaded in micelles using a co‐solvent evaporation method. High drug‐loading content was obtained for worm‐like micelles. in vitro drug release was performed at 37°C in pH 7.4 phosphate‐buffered saline. An initial burst release is detected in all cases, followed by slower release up to 9 days. The overall release rate is strongly dependent on the degradation of micelles. Copolymers with short PLGA blocks exhibit faster drug release due to faster degradation of micelles, and worm‐like micelles present slower drug release as compared to spherical ones. Therefore, PLGA‐PEG copolymer micelles with high drug‐loading capacity, different architectures, and variable drug release rates could be most attractive for sustained delivery of valsartan.

中文翻译：

---

由聚（D，L-丙交酯-乙交酯）-聚（乙二醇）嵌段共聚物制备的自组装胶束，用于缬沙坦的持续释放

通过D，L的开环聚合反应合成了不同组成的聚（D，L-丙交酯-乙交酯）-聚乙二醇（PLGA-PEG）二嵌段共聚物。-丙交酯和乙交酯，使用单甲氧基PEG作为大分子引发剂。通过核磁共振，凝胶渗透色谱和临界胶束浓度分析对所得共聚物进行表征。共聚物的自组装产生了不同结构的聚集体，包括球形胶束以及带有Y形接头的球形和蠕虫状胶束的混合物。自组装结构取决于亲水/疏水平衡和共聚物的摩尔质量。使用共溶剂蒸发法将缬沙坦（一种广泛用于治疗高血压的药物）装入胶束中。蠕虫状胶束的载药量较高。体外药物释放是在37°C的pH 7.4磷酸盐缓冲盐水中进行的。在所有情况下都检测到初始突发释放，然后缓慢释放长达9天。总体释放速率在很大程度上取决于胶束的降解。PLGA嵌段短的共聚物由于胶束的降解更快，因此释放的药物更快，而蠕虫状的胶束与球形的相比，药物的释放较慢。因此，具有高载药量，不同结构和可变药物释放速率的PLGA-PEG共聚物胶束对于缬沙坦的持续输送最有吸引力。