Kovalchuk Andrey, Fischer Wilfried, Epple Matthias
Institute of Inorganic Chemistry, University of Duisburg-Essen, Universitaetsstr. 5-7, D-45111 Essen, Germany.
Macromol Biosci. 2005 Apr 19;5(4):289-98. doi: 10.1002/mabi.200500033.
Two microporous biodegradable polyesters, i.e., PGA and PDLLA, were obtained by solid-state polymerization reaction from the sodium salts of the corresponding alpha-hydroxycarboxylic acids after washing out the by-product sodium chloride. The polymers were shaped by cold uniaxial pressing, by hot uniaxial pressing, and by extrusion at elevated temperature. Due to the special microporosity of the polymers, the introduction of drugs is possible at moderate temperature. The release kinetics of the model drug Phe and of the anti-tumor drug goserelin (an LH-RH agonist) from compacted polymer samples were fast (approx. 2 d). The release kinetics of goserelin were corrected for the decomposition of the drug. External coatings with PDLLA or PLLA obtained by immersion in polymer solution strongly slowed down the release kinetics in the case of the PDLLA coating, giving an almost linear release during 100 d. A coating with PLLA was unsuitable to slow down the release kinetics.
通过固态聚合反应，从相应α-羟基羧酸的钠盐中洗去副产物氯化钠后，得到了两种微孔可生物降解聚酯，即聚乙醇酸（PGA）和聚消旋乳酸（PDLLA）。这些聚合物通过冷单轴压制、热单轴压制以及在高温下挤出成型。由于聚合物具有特殊的微孔结构，在适中温度下即可引入药物。模型药物苯丙氨酸（Phe）和抗肿瘤药物戈舍瑞林（一种促黄体生成激素释放激素（LH-RH）激动剂）从压实的聚合物样品中的释放动力学很快（约2天）。戈舍瑞林的释放动力学针对药物分解进行了校正。通过浸入聚合物溶液获得的PDLLA或聚左旋乳酸（PLLA）外涂层在PDLLA涂层的情况下极大地减缓了释放动力学，在100天内呈现几乎线性的释放。PLLA涂层不适用于减缓释放动力学。
