Husmann M, Schenderlein S, Lück M, Lindner H, Kleinebudde P
Ferring GmbH, Wittland 11, Kiel, Germany.
Int J Pharm. 2002 Aug 21;242(1-2):277-80. doi: 10.1016/s0378-5173(02)00187-4.
This article deals with polymer erosion in biodegradable microparticles produced using the phase separation method. Poly(lactic-co-glycolic acid) copolymers with different compositions and molecular weights were employed. The microparticles were stored in phosphate buffer for 6 months. The molecular weight of the polymers was determined by size exclusion chromatography, and the weight loss was monitored gravimetrically. No weight loss was measured in the first weeks, although the molecular weight decreased significantly already from the start. After a certain storage period which was found to be specific for the type of polymer, the weight of the microparticles decreased rapidly. The start of this weight loss occurred when the molecular weight of the polymer in the degrading microparticles reached a threshold of approximately 15,000. This critical molecular weight was found to be identical for all investigated polymers, i.e. it was independent of the initial molecular weight of the polymer and of the lactic-glycolic ratio.
本文探讨了采用相分离法制备的可生物降解微粒中的聚合物侵蚀现象。使用了不同组成和分子量的聚（乳酸 - 乙醇酸）共聚物。将微粒在磷酸盐缓冲液中储存6个月。通过尺寸排阻色谱法测定聚合物的分子量，并采用重量法监测重量损失。在最初几周未检测到重量损失，尽管分子量从一开始就显著下降。经过特定的储存期（发现该储存期因聚合物类型而异）后，微粒的重量迅速下降。当降解微粒中聚合物的分子量达到约15,000的阈值时，开始出现这种重量损失。发现所有研究的聚合物的这个临界分子量是相同的，即它与聚合物的初始分子量以及乳酸 - 乙醇酸比例无关。
