动静态浸泡体系对聚乙交酯丙交酯体外降解产物的影响

Influence of the dynamic and static degradable systems on poly-DL-lactide-co-glycolide degradable products in vitro

目的:了解动静态浸泡体系对聚乙交酯丙交酯体外降解产物乳酸和乙醇酸生成的影响。方法:实验于2002-09/12在上海第二医科大学附属第九人民医院口腔材料科,上海市生物材料研究测试中心实验室进行。取2cm×2cm大小的聚乙交酯丙交酯材料片,浸泡介质为磷酸盐缓冲液(pH=7.4),分别在37℃恒温静态和动态(往返振荡速率为160次/min)条件下浸泡。于0周(浸泡前)以及浸泡后2,3,4,6,8和10周通过气相色谱法测定材料的水溶性降解产物乳酸及乙醇酸的质量,每时间点5片。在整个浸泡过程中,浸泡体系的浸泡介质不进行更换。推算标准品乙醇酸的衍生化标准曲线为:yG=a1x+b1;标准品乳酸的衍生化标准曲线为:yL=a2x+b2。由气相色谱图可计算出乙醇酸与苯甲酸的峰面积比值x1,再带入上述公式计算出乙醇酸和乳酸生成量。结果:动静态浸泡体系中聚乙交酯丙交酯降解产物乳酸和乙醇酸的质量生成情况:经过第0周(浸泡前),2,3,4,6,8和10周浸泡后,浸泡液中降解产物乳酸和乙醇酸的质量是增加的。在动态系统中生成的降解产物乳酸和乙醇酸均显著高于静态体系中生成的质量[(4.21±1.49),(3.76±1.52)mg,t=3.798,P<0.01;(23.30±6.73),(20.00±5.86)mg,t=3.865,P<0.01]。结论:动态体系可以促进降解产物乳酸和乙醇酸的质量生成,使材料降解速度加快。

AIM： To study the influence of dynamic and static degradable systems on the poly-DL-lactide-co-glycolide（PGLA） degradable products in vitro, lactic acid（LA） and glycolic acid（GA）. METHODS： The experiment was conducted in the Department of Oral Materials, Ninth People＇s Hospital, Shanghai Second Medical University, Shanghai Biomaterials Research and Test Center from September to December 2002. The PGLA pieces at 2cm×2cm were immersed in phosphate buffer（PBS, pH 7.4） to degrade at 37℃; under two degradable systems： static and dynamic（the level agitation velocity was 160 times per minute）. The mass of water-soluble degradable products LA and GA was determined before and 2, 3, 4, 6, 8 and 10 weeks after immersion in PBS with 5 pieces of PGLA each by gas chromatography. No degradahle solution was refreshed during the experimental period. The derived standard curve of standard product GA were described based on yc=a1x＋b1, and that of standard product LA was described based on yL=a2x＋b2.The peak area ratio of GA to benzoic acid （x1） was calculated by gas chromatography, and then the x1 values was used in the above two formulae of GA and LA mass. RESULTS： The mass of the degradable products GA and LA in the dynamic and static degradable systems： The mass of degradable products GA and LA was increased in the immersion solution at 0, 2, 3, 4, 6, 8 and 10 weeks after immersion. The mass of GA and LA was significant more in the dynamic degradable system than in the static degradable system[（4.21±1.49） mg vs （3.76±1.52） mg, t=3.798, P 〈 0.01 for LA, （23.30±6.73） mg vs （20.00±5.86） mg, t=3.865,P 〈 0.01 for GA]. CONCLUSION： The dynamic degradable system can increase the mass of the PGLA degradable products GA and LA, and accelerate the degradation speed of biomaterials.