聚乳酸、乳酸乙醇酸共聚物的制备及其体外降解

以外消旋乳酸、左旋乳酸和乙醇酸为原料,制备高纯度交酯单体丙交酯和乙交酯,以辛酸亚锡引发在高真空条件下本体熔融开环聚合,制得一系列不同分子量的聚乳酸均聚物和不同配比的乳酸乙醇酸共聚物,并用核磁共振氢谱、凝胶渗透色谱、差示扫描量热仪等手段对聚合产物的结构和性能进行分析表征.将溶液涂膜法制备的聚乳酸均聚物和乳酸乙醇酸共聚物薄膜置于Hank's人工模拟体液中降解试验,记录聚合物薄膜的失重和黏度及表面形貌变化,考察其体外降解规律,筛选适合作为冠脉支架表面载药涂层的聚合物,以推测其在人体内的降解行为.

Preparation and In-vitro Degradation of Polylactide and Poly(L-lactide-co-glycolide)

In this paper,DL-lactide,L-lactide and glycolide were synthesized from DL-lactic acid,L-lactic acid and glycolic acid respectively.A set of homopolymerizations of lactide with stannous octoate as initiator and laurly alcohol as co-initiator was carried out;a series of copolymers of poly(L-lactide-co-glycolide)(PLGA) were prepared via ring-opening polymerization of DL-lactide or L-lactide and glycolide with stannous octoate in high vacuum.The structure and properties of homopolymers and copolymers were characterized by 1H-NMR spectroscopy, differential scanning calorimetry and gel permeation chromatography.The in vitro degradation behavior of polylactide(PLA) and PLGA films in Hank's solution was investigated.The hydrolytic degradation of the PLA and PLGA was monitored by measuring the changes of inherent viscosity and weight loss of the resulting samples.The degradation rate of PLGA could be adjusted by changing the composition of the copolymer and be enhanced with the glycolide content increasing.It is suggested that the PLGA copolymer is a potential material as drug elusion coating on coronary stents.