Tyler B J, Ratner B D
Department of Chemical Engineering, University of Washington, Seattle 98195.
J Biomed Mater Res. 1993 Mar;27(3):327-34. doi: 10.1002/jbm.820270306.
In vitro degradation of two lots of Biomer, a commercial poly(ether urethane urea), has been investigated in order to understand possible mechanisms for in vivo degradation. Two lots of Biomer, BSUA001 and BSP067, were used in the study. Lot BSUA001 contained a poly(diisopropylaminoethyl-methacrylate), an ultraviolet-stabilizing additive. This additive was absent in lot BSP067. Samples of each lot were exposed to two hydrolytic enzymes, papain and leucine aminopeptidase, and to hydrogen peroxide for 24 h. The extent of degradation was assessed using high-pressure gel permeation chromatography and x-ray photoelectron spectroscopy (XPS). Statistically significant changes in the molecular-weight distribution occurred in lot BSP067 for all three treatments. Only the hydrogen peroxide treatment resulted in statistically significant changes in the molecular weight of lot BSUA001. XPS data for samples of lot BSUA001 that had been treated with hydrogen peroxide revealed the formation of nitroso groups and protonated amines at the surface. The data suggest that surface chemistry is important for enzyme catalyzed degradation, while permeability is important for degradation by hydrogen peroxide.
为了了解体内降解的可能机制，对两批商业聚（醚聚氨酯脲）Biomer在体外的降解情况进行了研究。该研究使用了两批Biomer，即BSUA001和BSP067。批次BSUA001含有聚（甲基丙烯酸二异丙氨基乙酯），一种紫外线稳定添加剂。批次BSP067中没有这种添加剂。将每批样品分别暴露于两种水解酶（木瓜蛋白酶和亮氨酸氨肽酶）以及过氧化氢中24小时。使用高压凝胶渗透色谱法和X射线光电子能谱（XPS）评估降解程度。对于所有三种处理，批次BSP067的分子量分布均发生了具有统计学意义的变化。只有过氧化氢处理使批次BSUA001的分子量发生了具有统计学意义的变化。用过氧化氢处理过的批次BSUA001样品的XPS数据显示，其表面形成了亚硝基和质子化胺。数据表明，表面化学对于酶催化降解很重要，而渗透性对于过氧化氢降解很重要。
