Nakamura T, Hitomi S, Watanabe S, Shimizu Y, Jamshidi K, Hyon S H, Ikada Y
Department of Experimental Surgery, Kyoto University, Japan.
J Biomed Mater Res. 1989 Oct;23(10):1115-30. doi: 10.1002/jbm.820231003.
In order to study the effects of factors governing the bioabsorption rate of polylactides, implantation tests were carried out in rabbits using various samples (20 x 10 x 2 mm3) differing in their chemical composition, residual monomer content, and molecular orientation. Copolymer samples with a higher lactic acid content showed a lower rate of absorption, whereas those with a higher unreacted monomer content were absorbed faster and showed a more drastic decrease in molecular weight. In contrast, degradation of the purified polymers was slow; the purified poly-L-lactide showed no weight change and a 50% reduction in molecular weight after 6 months of implantation. Scanning electron microscopy of the samples containing monomers showed a microporous structure extending from the surface to the inner region a few days after implantation, whereas the purified poly-L-lactide did not exhibit a microporous structural change even after 10 months of implantation.
为了研究影响聚乳酸生物吸收速率的因素，使用化学组成、残留单体含量和分子取向不同的各种样品（20×10×2立方毫米）在兔子身上进行了植入试验。乳酸含量较高的共聚物样品显示出较低的吸收速率，而未反应单体含量较高的样品吸收更快，且分子量下降更为显著。相比之下，纯化聚合物的降解较慢；纯化的聚-L-乳酸在植入6个月后重量没有变化，分子量降低了50%。植入几天后，含有单体的样品的扫描电子显微镜显示出从表面延伸到内部区域的微孔结构，而即使在植入10个月后，纯化的聚-L-乳酸也没有表现出微孔结构变化。
