Investigation of the degradation behaviour of poly(ethylene glycol-co-D,L-lactide) copolymer
Investigation of the degradation behaviour of poly(ethylene glycol-co-D,L-lactide) copolymer
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DOI：
10.1016/j.polymdegradstab.2007.06.020
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发表时间：
2007-09-01
影响因子：
5.9
通讯作者：
Conti, Bice
中科院分区：
文献类型：
--
作者：
Dorati, Rossella;Genta, Ida;Conti, Bice
目的是研究聚（乙二醇-co- d， l-丙交酯）（PEG-D,L-PLA）多嵌段共聚物的降解行为，散装和微球，在水介质中。比较了聚乳酸均聚物在体和微球中的降解行为。采用双乳液溶剂蒸发法制备微球。采用核磁共振（NMR）和调制差示扫描量热法（MDSC）对原料聚合物和微球进行了物理化学表征。用GPC法评价聚合物在水环境中孵育前后的分子量；水分吸收和质量损失用重量法测定。聚乳酸链内聚乙二醇片段的存在使微球具有海绵状结构。与散装聚合物相比，微球配方的聚合物t值显着增加。在水环境中培养63天后，PEG-D，L-PLA微球达到平均M值，降低47%，而PLA微球则降低20%。聚乙二醇-聚乳酸、l -聚乳酸和聚乳酸相应的M-W下降幅度较大，分别为72%和41%。数据显示聚合物在水环境中的降解行为与相应微球的降解行为有显著不同。这些结果强调了对微球配方进行彻底的物理化学表征的重要性。(C) 2007 Elsevier Ltd.版权所有。
The aim was to investigate the degradation behaviour of poly(ethylene glycol-co-D,L-lactide) (PEG-D,L-PLA) multiblock copolymer, in bulk and as microspheres, in aqueous medium. The degradation behaviour of PLA homopolymers in bulk and microspheres was evaluated as comparison.Microsphere preparation was performed by the double emulsion solvent evaporation method. Physical-chemical characterization of the raw polymers and the microspheres was performed by nuclear magnetic resonance (NMR) and modulated differential scanning calorimetry (MDSC). Polymer molecular weight, before and after incubation in aqueous environment, was evaluated by GPC; water uptake and mass loss were determined gravimetrically.The presence of PEG segments inside PLA chains gave a characteristic spongy structure to the microspheres. A significant increase in polymer T. values was found for the microsphere formulations compared to polymer in bulk. After 63 days of incubation in the aqueous environment, the PEG-D,L-PLA microspheres achieved an average M, reduction of 47% compared to 20% for PLA microspheres. The corresponding M-W decrease of the polymers in bulk was significantly higher: 72% and 41% for PEG-D,L-PLA and PLA, respectively.The data show how the degradation behaviour of polymer in bulk in an aqueous environment is significantly different from the behaviour of the corresponding microspheres. These results highlight the importance of performing a thorough physical-chemical characterization on microsphere formulations. (C) 2007 Elsevier Ltd. All rights reserved.