The in vivo degradation of poly (epsilon-caprolactone)(PCL) was observed for 3 years in rats. The distribution, absorption and excretion of PCL were traced in rats by radioactive labeling. The results showed that PCL capsules with initial molecular weight (Mw) of 66000 remained intact in shape during 2-year implantation. It broke into low molecular weight (Mw=8000) pieces at the end of 30 months. The Mw of PCL deceased with time and followed a linear relationship between logMw and time. Tritium-labeled PCL (Mw 3000) was subcutaneous implanted in rats to investigate its absorption and excretion. The radioactive tracer was first detected in plasma 15 days after implantation. At the same time radioactive excreta was recovered from feces and urine. An accumulative 92% of the implanted radioactive tracer was excreted from feces and urine by 135 days after implantation. In the mean while, the plasma radioactivity dropped to the background level. Radioactivity in the organs was all close to the background level confirming that the material did not cumulate in body tissue and could be completely excreted.

中文翻译：

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基于PCL的植入物的体内降解，吸收和排泄。

在大鼠中观察到聚ε-己内酯（PCL）的体内降解3年。通过放射性标记追踪大鼠体内PCL的分布，吸收和排泄。结果表明，初始分子量（Mw）为66000的PCL胶囊在植入2年后仍保持完整的形状。30个月末，它分解为低分子量（Mw = 8000）的碎片。PCL的Mw随着时间而降低，并遵循logMw与时间之间的线性关系。将标记的PCL（Mw 3000）皮下植入大鼠体内以研究其吸收和排泄。植入后15天首先在血浆中检测到放射性示踪剂。同时，从粪便和尿液中回收了放射性排泄物。植入后135天，累积的92％的放射性示踪剂已从粪便和尿液中排出。同时，血浆放射性降至背景水平。器官中的放射性都接近本底水平，这证实了该物质没有在人体组织中累积并且可以被完全排泄。