Mauduit J, Pérouse E, Vert M
Laboratoires Pérouse Implants, Bornel, France.
J Biomed Mater Res. 1996 Feb;30(2):201-7. doi: 10.1002/(SICI)1097-4636(199602)30:2<201::AID-JBM10>3.0.CO;2-P.
Biodegradable films were prepared by casting acetone solutions of mixtures of a high molecular weight poly(DL-lactic acid) (HMW-PLA50) with 0, 10, and 30% w/w poly(DL-lactic acid) oligomers (LMW-PLA50), before drying. From size exclusion chromatography (SEC) it was shown that degradation occurred during film processing, in agreement with the acid-catalyzed degradation of polyesters. The higher the content of LMW-PLA50, the larger the decrease of the molar masses. The three selected film formulations were then allowed to age in isoosmolar 0.13M, pH 7.4 sodium phosphate buffer at 37 degrees C. The hydrolytic degradation was monitored by using various techniques, namely weighing to quantify water absorption and weight loss, SEC to evaluate molar mass changes, head space gas chromatography to assess the desorption of residual acetone, and enzymatic assay of the L-lactic acid released in the aging media. The presence of LMW-PLA50 clearly accelerated film degradation. Moreover, it was shown that the mechanism of degradation greatly depended on the content in the oligomers.
在干燥之前，通过浇铸高分子量聚（DL-乳酸）（HMW-PLA50）与0%、10%和30% w/w聚（DL-乳酸）低聚物（LMW-PLA50）混合物的丙酮溶液来制备可生物降解薄膜。尺寸排阻色谱法（SEC）表明，在薄膜加工过程中发生了降解，这与聚酯的酸催化降解一致。LMW-PLA50的含量越高，摩尔质量的下降幅度越大。然后，将三种选定的薄膜配方置于37℃的等渗0.13M、pH 7.4的磷酸钠缓冲液中老化。通过使用各种技术监测水解降解，即称重以量化吸水率和重量损失，SEC评估摩尔质量变化，顶空气相色谱法评估残留丙酮的解吸，以及对老化介质中释放的L-乳酸进行酶促测定。LMW-PLA50的存在明显加速了薄膜降解。此外，结果表明，降解机制很大程度上取决于低聚物中的含量。
