Abstract

BACKGROUND:Poly(lactic-co-glycolic acid) (PLGA) has been widely used as medical implants and drug vehicle. Due to various factors involved in the degradation process, it is rather difficult to simulate the mass loss properties of PLGA.
OBJECTIVE: To investigate the mass loss properties of PLGA films, and observe the correlation between the stimulation and the factual measurement.
DESIGN: Repeated measuring experiment.
SETTING: School of Materials Science and Engineering, Dalian University of Technology.
MATERIALS: PLGA 50:50, 70:30 and 75:25 with weight average molecular weight (Mw) of 63 000, 115 000 and 400 000 were purchased from Shandong Key Laboratory of Medical Polymer Materials, and 1,4-dioxane (analytically pure) was purchased from Tianjin No.1 Chemical Reagent Factory and used as solvent.
METHODS: The experiments were carried out in the School of Materials Science and Engineering of Dalian University of Technology from April to July in 2006.①PLGA were dissolved in 1, 4-dioxane according to the mass ratio of 50:50, 70:30 and 75:25, and the solution were cast into 10 mm×10 mm×1 mm polymer films.②PLGA films were immersed in Hank's simulated body fluid (pH 7.4) at 37 ℃, and then taken out every week (every 5 days for PLGA 50:50). The samples were washed and dried to measure the changes of number and Mw using gel permeation chromatography. Degradation velocity was also worked out. Meanwhile the mass loss properties of PLGA films were measured using electronic balance. Furthermore, an improved Monte Carlo method was applied to carry out the correlation analysis with experiment data.
MAIN OUTCOME MEASURES: ①degradation rates of PLGA with different ratios of lactic acid and glycolic acid.②the correlation coefficient between simulation results and experiment data.
RESULTS: ①The degradation rates for PLGA at 50:50, 70:30 and 75:25 were 0.058 5, 0.016 6 and 0.010 1 /d (based on Mn), or 0.061 0, 0.017 5 and 0.008 5 /d (based on Mw), respectively.②Correlation coefficients between simulation results and experiment data for PLGA 50:50, 70:30 and 75:25 were 0.973 6, 0.987 4 and 0.990 3 correspondingly.
CONCLUSION: The numerical simulation results for the mass loss properties of PLGA fit the experiment data well.

School of Materials Science and Engi-neering, Dalian University of Tech-nology, Dalian 116024, Liaoning Province, China

Qi Min☆, Doctor, Professor, Tutor of doctor, School of Materials Science and Engineering, Dalian University of Technology, Dalian 116024, Liaoning Province, China
minqi@dlut.edu.cn

Supported by: the National Natural Science Foundation of China, No. 30470521*

Received:2007-10-29
Accepted:2007-11-05 (07-50-10-5906/YWY)

Qi M, Liu HZ, Wei ZY, Huang YY.Monte Carlo simulation of poly(lactic-glycolic acid) films degra-dated in simulated body fluid.Zhongguo Zuzhi Gongcheng Yanjiu yu Linchuang Kangfu 2008;12(6): 1153-1156(China)
[www.zglckf.com/zglckf/ejournal/upfiles/ 12-6/6k-1153
(ps).pdf]

摘要
背景：聚乳酸-乙醇酸广泛应于医用植入物与药物缓释载体，由于影响其降解过程的因素较多，使得其失重性能难以模拟。
目的：对聚乳酸-乙醇酸膜失重性能进行数值模拟，观察模拟与实际测量的相关性。
设计：重复测量。
单位：大连理工大学材料科学与工程学院。
材料：重均分子量分别为63 000, 115 000和400 000的实验用的聚乳酸-乙醇酸 50/50，70/30 和75/25，购自山东省医用高分子材料重点实验室。1,4-二氧六环为天津化学试剂一厂生产，用作溶剂。
方法：实验于2006-04/06在大连理工大学材料科学与工程学院完成。①将聚乳酸-乙醇酸分别按质量比50∶50，70∶30及75∶25溶于1,4-二氧六环，溶液浇铸成10 mm×10 mm×1 mm的聚合物膜。②聚乳酸-乙醇酸膜在37 ℃的Hank's模拟体液（pH 7.4）中浸泡，每周取出1次（质量比为50：50的聚乳酸-乙醇酸为每5天取1次），试样清洗并干燥之后使用凝胶渗透色谱仪测量其数均与重均分子量，计算降解速率。同时使用电子天平测量其失重性能，并与Monte Carlo法改进后实际测量值进行相关性分析。
主要观察指标：① 不同质量比聚乳酸-乙醇酸的降解速率。② 模拟结果与实验值之间的相关系数。
结果：①质量比50：50，70：30和75：25的聚乳酸-乙醇酸降解速率分别为0.058 5，0.016 6和0.010 1/d（数均分子量）或者0.061 0，0.017 5和0.008 5/d（重均分子量）。②聚乳酸-乙醇酸 50/50，70/30和75/25的模拟结果与实验值之间的相关系数分别为0.973 6，0.987 4 和0.990 3。
结论：数值模拟聚乳酸-乙醇酸膜失重性能与实验值符合良好。
关键词：聚乳酸-乙醇酸；Monte Carlo法；降解；溶蚀；失重性能

齐 民，刘洪泽，魏志勇，黄莹莹
大连理工大学材料科学与工程学院，辽宁省大连市 116024
齐 民☆，男，1960年生，吉林省怀德镇人，汉族，1994年大连理工大学毕业，博士，教授，博士生导师，主要从事非晶、纳米材料及生物材料的研究。
国家自然科学基金资助项目（30470521）*

中图分类号: R318.08 文献标识码: A 文章编号: 1673-8225(2008)06-01153-04
齐民，刘洪泽，魏志勇，黄莹莹．聚乳酸-乙醇酸膜在模拟体液中降解的Monte Carlo 模拟[J].中国组织工程研究与临床康复，2008，12(6):1153-1156
[www.zglckf.com/zglckf/ejournal/upfiles/12-6/6k-1153(ps).pdf]
(Edited by: Nie J/Yang Y/Wang L)