Methoxy-poly(ethylene glycol)-block-poly(l-lactide-random-glycolide) (mPEG-PLGA) with relatively high monomer conversion, fixed LA/GA ratio, controlled molar mass, and random PLGA sequences was synthesized under microwave irradiation at 120 °C. The microstructure, i.e., the sequence of lactyl and glycolyl units, of the PLGA block was analyzed using proton and carbon-13 nuclear magnetic resonance spectroscopy. It was found that the second mode transesterification of glycoldyl units (-GG-) happened shortly after the reaction started and lasted during the reaction, and that of lactidyl units (-LL-) happened gradually from 1 to 30 min under microwave. Compared with traditional oil-bath heating copolymerization, microwave irradiation not only greatly increases polymerization rate but also induces rapid transesterification and achieves high randomness of the PLGA block at low reaction temperature. Nanoparticles with diameter ranging from 60 to 100 nm were also prepared from these mPEG-PLGA copolymers with varied molar mass of PEG (2k and 5k g/mol) and PLGA blocks (20k-160k g/mol), showing such block copolymer can be harnessed as drug delivery matrix in nanomedicine.

甲氧基-聚（乙二醇） -嵌段-聚（升-lactide-随机-glycolide）（MPEG-PLGA）具有相对高的单体转化率，固定LA / GA比，控制摩尔质量，和随机PLGA序列在微波辐射下合成在120°C下。使用质子和碳13核磁共振波谱分析PLGA嵌段的微观结构，即乳糖基和乙醇酰基单元的序列。有人发现，glycoldyl单位第二模式酯交换（-GG-）发生反应开始后不久，反应过程中持续，而中lactidyl单位（-11-）在微波作用下从1到30分钟逐渐发生。与传统的油浴加热共聚相比，微波辐射不仅大大提高了聚合速率，而且引发了快速的酯交换反应，并在低反应温度下实现了PLGA嵌段的高度无规化。还从这些具有不同摩尔质量的PEG（2k和5k g / mol）和PLGA嵌段（20k-160k g / mol）的mPEG-PLGA共聚物中制备了直径范围为60至100 nm的纳米颗粒，表明这种嵌段共聚物可以在纳米医学中用作药物传递基质。