【作者】 潘长江；

【导师】 黄楠；

【作者基本信息】 西南交通大学 ， 材料学， 2006， 博士

【摘要】 经皮冠状动脉成形术以及支架植入术后的再狭窄是当前世界上心血管疾病介入治疗领域内的一个主要难题。目前临床上广泛应用的雷帕霉素和紫杉醇洗脱支架仍然存在抗凝血性能不足的问题，并且所用的不可降解高分子载体材料在体内的长期放置所导致的结构性能变化也可能引发相关的临床并发症。针对上述问题，本论文以具备可控降解行为的生物降解高分子材料作为药物释放载体，发展既含有抗增生药物又含有抗凝血药物的涂层材料，研制既具有抗增生又具有抗凝血作用的药物洗脱支架：依据一些中药提纯物具有抗增生和抗凝血的综合特性，本论文也开展了中药提纯药物应用于药物洗脱支架的探索性研究。依据药物的控释需求、材料的降解行为以及生物材料的临床准入性，粘均分子量为95800的乙交酯-丙交酯共聚物（PLGA）被确定为本论文中血管支架的药物载体材料。抗增生药物雷帕霉素和紫杉醇、抗凝血性药物肝素以及中药提纯药物姜黄素、大黄素被选定为本论文的药物研究对象。利用超声雾化喷涂方法分别制备了五种含单一药物（雷帕霉素、紫杉醇、肝素、姜黄素、大黄素）以及三种含混合药物（雷帕霉素／肝素、雷帕霉素／姜黄素以及姜黄素／肝素）的药物洗脱血管支架。药物洗脱血管支架撑开前后表面形貌的对比研究表明：涂层均匀连续完整，无交联，AFM测量的平均粗糙度小于1nm，药物洗脱支架装配到3.0×20mm的血管成型球囊上后撑开，涂层没有剥落和裂纹，显示出与不锈钢基底良好的结合力。傅立叶变换红外光谱和X射线光电子能谱的结果均表明药物的吸收峰在药物洗脱薄膜中没有发生移动。药物洗脱支架的体外药物释放行为研究表明，不同的药物具有不同的释放行为，姜黄素和大黄素在测量的时间范围内呈现出较好的近似零级释放行为，但是姜黄素的释放速度大于大黄素的释放速度，如载药量为20％的支架，姜黄的释放速度为7.37μg／天，而大黄素为4.9μg／天，释放速度的不同导致了释放周期的差别；雷帕霉素的释放行为存在2天的突释期，并且药物含量越大，突释越明显，突释量达到4.7％—20％，突释后的释放呈现出较好的近似零级释放关系；肝素洗脱支架没有突释，整个释放过程呈现出近似零级释放关系，混合药物洗脱（雷帕霉素／肝素，姜黄素／肝素）支架中肝素的释放行为呈现出较好的零级释放行为，但是雷帕霉素和姜黄素的释放行为与单一药物洗脱支架的差别不大，只是释放速度不一样；载药量对释放速度具有比较明显的影响，载药量越大，释放速度越快，但是释放速度的增加比例与药物／高分子的比例的增加不一致。在雷帕霉素支架表面制备PLGA20000控制释放层，可以基本消除雷帕霉素的突释效应，并且延长药物的释放周期。综合静态血小板吸附，部分凝血活酶时间，纤维蛋白原吸附以及GMP140释放评价实验结果，与不锈钢和纯PLGA的支架涂层相比较，分别载有肝素和姜黄素的PLGA支架涂层都具有良好的抗凝血性，而载有雷帕霉素的PLGA支架涂层具有一定的抗凝血性。在雷帕霉素药物洗脱支架中加入姜黄素可以提高雷帕霉素药物洗脱支架的抗凝血性，在姜黄素洗脱支架涂层中加入肝素可以进一步提高其抗凝血性能，这为研制同时具有抗增生和抗凝血功能的药物洗脱支架奠定了很好的基础。LDH，Alamar Blue^TM以及细胞染色等细胞生物学评价结果为：与不锈钢相比，包覆雷帕霉素，姜黄素以及肝素涂层的PLGA都具有抑制平滑肌细胞生长和增殖的作用，其中抑制作用的有效性排序为雷帕霉素＞姜黄素＞肝素，并随着载体材料中药物浓度的增加，抑制平滑肌细胞增生的作用越明显。更多还原

【Abstract】 Currently, restenosis after percutaneous transluminal coronary angioplasty （PTCA） and stent implantation is the major difficult problem of the field of cardiovascular intervention therapy in the world. The anticoagulation of clinical rapamycin and paclitaxel eluting stents is still deficient; furthermore, the long-standing nonbiodegradable polymer drug carrier in human body may also bring many clinical complications because of the change of its structure and properties. To above questions, this study aimed at developing a novel drug-eluting stent with a biodegradable polymer coating which contained not only antiproliferative drug but anticoagulation drug. Considering the good anticoagulation and anti-proliferation of some Chinese herbal drug, this paper carried out some exploring studies of these drugs eluting stentsAccording to the controlled release requirements, biodegradable behavior and the clinical admittance of biodegradable biomaterials, the PLGA （poly lactide-co-glycoide） （Its average-viscosity molecular weight was 95800, LA/GA=85/15） was chosen as the drug carrier in this paper. Anti-proliferative drug including rapamycin and paclitaxel, anticoagulation drug such as heparin and Chinese herbal drug including curcumin and emodin were investigated. Five single drug-eluting stents （rapamycin, paclitaxel, curcumin, emodin and heparin） and three mixing-drug eluting stents （rapamycin-heparin, curcumin-heparin and rapamycin-curcumin） were prepared using ultrasonic atomization spray method.The comparative results of pre- and post-dilation morphology of drug eluting stents indicated that the coating was very smooth, uniform and integrated. There were no webbings and "bridges" between struts. The avergae roughness of coating measured by atomic force microscopy （AFM） was below 1nm. The drug-eluting stents were mounted onto a angioplasty balloon （3.0×20mm） and then dilated, the coating did not peel and crack, suggesting that the coating had the ability to withstand the compressive and tensile strains imparted during this process. The results of Fourier transform infrared spectroscopy （FTIR） and X-ray photoelectron spectroscopy （XPS） indicated that there was no peak shift for drug in drug-eluting PLGA films. The results of in vitro drug release profile from stents indicated that different drug had different release behavior. The release profile of curcumin and emodin from stents exhibited approximate zero-order release profile, however, the release rate of curcumin was larger than emodin, for example, the curcumin-eluting stent which contained 20wt% curcumin was 7.37μg/day and that of emodin was 4.9μg/day, the different release rate resulted in different release period. The release behavior of rapamycin from stent had a two phase release profile with a burst release within 2 days, the burst release changed from 4.7% to 20% with the increase of drug content from 15% to 40%, after initial burst release （2 days） followed by a longer lasting, slower sustained release, the decreased release phase appeared to a approximate zero-order release model. The heparin release from heparin-eluting stents had an approximate zero-order release profile without burst release and the heparin release of rapamycin-heparin and curcumin-heparin eluting stents exhibited good zero-order profile, however, the release behavior of rapamycin and curcumin was similar with corresponding single drug-eluting stents and the release rate was different. The drug content influenced the release rate significantly and the release rate increased with the increase of drug content but was not proportional to ratio of drug-polymer. The control release layer prepared from PLGA20000 onto single rapamycin-eluting stent surface can eliminate the burst release of rapamycin and prolong the release period of rapamycin.In this study, platelet adhesion and activation （GMP140, P-selection）, activated partial thromboplastin time （APTT） and fibrinogen adsorption were used to characterize the blood compatibility of drug-eluting stent. Compared with stainless steel and single PLGA coating stent, the heparin and curcumin eluting stents had a good hemocompatibility, however, the blood compatibility of rapamycin-eluting stent was deficient. Incorporating curcumin in rapamycin-eluting stents can improve the anticoagulation of rapamycin-eluting stent. Loading heparin in curcumin-eluting stent further enhanced the anticoagulation of curcumin-eluting stent. This established good base for developing drug-eluting stents which had not only good anticoagulation but also anti-proliferation.The biological evaluation results of LDH, Alamar Blue^TM and cell staining indicated that three kinds of drug-loaded films, including rapamycin, curcumin, heparin loading PLGA films, all can inhibit smooth muscle cell grow and proliferate compared with stainless steel and PLGA. The order of effect was rapamycin＞curcumin＞heparin. The anti-proliferation effect improved with the increase of drug content.更多还原