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以戊二酸锌为催化剂合成可降解聚碳酸亚丙亚乙酯(PPEC,MW=229.338kDa)并首次将其作为载药涂层材料进行研究。核磁共振氢谱(1 H NMR)显示分子链中环氧乙烷和环氧丙烷的贡献与原料中两者配比相同,碳酸酯段含量为76.7%。差示扫描量热仪(DSC)测得玻璃化转变温度(Tg)为16.8℃。拉伸实验得到断裂伸长率为550%。衰减全反射-傅立叶变换红外光谱(ATR-FT-IR)显示药物涂层中PPEC和雷帕霉素之间没有发生明显的化学反应。球囊扩张实验后用扫描电子显微镜(SEM)观察到药物涂层支架表面完整光滑,没有剥落翘起的现象。药物洗脱支架在模拟体液(PBS,pH值=7.4)中药物释放时间超过60d,速率由快变慢。实验表明PPEC作为支架涂层材料具有广阔的应用前景。 相似文献
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柔顺性是冠脉支架很重要的一个力学性能,它决定了支架的输送性及血管内支架的适应性。利用有限元法对6种不同结构的镁合金冠状动脉支架进行模拟分析,主要研究其不同连接体结构对支架柔顺性能的影响。结果显示,在压握状态下,不同连接体结构对支架柔顺性能影响较大,其中S型支架柔顺性较好,直杆L型支架柔顺性较差;在扩张状态下,连接体和支撑体个数相同时主要取决于连接体的结构;无论是在压握状态还是扩张状态下,有圆弧形的连接体的支架柔顺性要优于直杆形连接体的支架。关于支架柔顺性能的模拟结果,为今后镁合金冠脉支架的结构优化设计和临床选择起到了指导作用。 相似文献
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冠脉支架表面PLGA涂层制备及其血液相容性研究 总被引:5,自引:2,他引:3
采用静电喷涂沉积(electrospray deposition ESD)法在冠脉支架表面制备了PLGA涂层.采用OLYMPUS体式显微镜、原子力显微镜(AFM)观察了涂层宏观表面形貌及三维形貌;通过对涂层支架进行球囊扩张考察了PLGA涂层与支架的结合力;通过血小板粘附实验和动态凝血时间测定研究PLGA涂层的血液相容性.结果表明:ESD法在冠脉支架表面制备PLGA涂层,支架筋拐角处无明显的聚合物胶体缠绕、粘连且涂层表面光滑;PLGA涂层将316L不锈钢基体的微坑覆盖,基体Ra=16.174nm,PLGA涂层Ra=0.149nm,涂层表面粗糙度小;涂层支架撑开后在最大塑性变形位置无涂层撕裂、翘起等缺陷,涂层与支架有良好结合力;PLGA涂层血小板粘附量少,变形小,未引起血小板激活,动态凝血时间长,直到50min未产生凝血,PLGA涂层具有较好的血液相容性. 相似文献
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冠脉支架表面载药涂层的制备和性能 总被引:7,自引:0,他引:7
采用溶液聚合法制备了改性的聚甲基丙烯酸树脂,作为支架表面载药涂层的药物载体聚合物.采用浸涂法制备了不锈钢基体表面聚合物及聚合物载药涂层,并利用红外光谱及核磁共振波谱分析了所制备共聚物的成分,并评价了物理性能、生物稳定性能以及药物的释放性能.结果表明,所制备的涂层具有较好的生物稳定性,甲基丙烯酸和甲基丙烯酸丁酯的加入提高了聚合物的物理性能,尤其是涂层与金属基体的结合力所制备的药物释放涂层具有缓释紫杉醇的功能,其释放周期超过15 d.聚甲基丙烯酸树脂携带紫杉醇的载药涂层在生物稳定性、物理性能及药物释放性能方面满足冠脉支架的表面涂层的使用要求. 相似文献
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本文利用溶剂灌制/粒子沥滤的方法将具有较强吸附性能的活性碳纤维(activated carbon fiber,ACF)掺杂于聚乳酸-羟基乙酸共聚物(poly(lactic-co-glycolic acid),PLGA)制备了一种新型ACF/PLGA骨组织工程复合支架。论文对比研究了纯PLGA支架以及两种ACF/PLGA支架(ACF含量为2.75%,8.26%)的结构和性能。SEM研究发现三者都具有较高的孔隙度,分别为73.5340%、75.1214%和79.8216%,且孔隙度随着ACF含量的增加逐渐增大;压汞法测得三者的孔径分布基本在50~250μm之间;研究其亲水性发现,其表面接触角随ACF含量增加逐渐减小,吸水率则逐渐增大。进一步研究发现在三种支架上种植小鼠成纤维细胞(L929),一天后细胞都较好粘附在支架上;ACF含量为8.26%的复合支架移植到小白鼠皮下组织,一月后HE切片显示支架周围组织的免疫排斥反应较小。掺杂ACF的PLGA复合支架除了具有良好的细胞粘附效果和组织相容性,相对于纯PLGA支架,还具有良好的孔径分布和亲水性,具有潜在的应用价值。 相似文献
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以戊二醛为交联剂,制备了pH敏感性明胶-果胶水凝胶(GT-PT)和明胶-辛基果胶水凝胶(GT-OPT),研究了交联剂用量、温度、pH值对凝胶溶胀性能的影响及溶胀-消溶胀性能。结果表明,当温度在30~60℃时,凝胶的溶胀率随温度的升高而增大;且具有明显的pH敏感性,碱性条件下的溶胀率大于酸性条件下的溶胀率;不同pH值条件下,明胶-果胶水凝胶具有"形状记忆"功能。包埋在水凝胶中的牛血清蛋白在pH=1.0时的释药率大于pH=7.8和pH=9.18时的释药率。此类水凝胶有望用于蛋白质的pH值及温度控制释放。 相似文献
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水凝胶作为性能良好的载体,在药物的控释、组织工程等领域有着广泛的应用。壳聚糖是一类天然的带正电荷的碱性多糖,由其形成的水凝胶具有较好的生物相容性、生物降解性、抗菌和低细胞毒性,因此,壳聚糖水凝胶有着良好的生物应用前景。本文综述了壳聚糖水凝胶的制备方法(包括物理交联法和化学交联法),在物理交联法部分着重介绍了离子化合物及聚电解质分子与壳聚糖通过离子交联形成水凝胶,以及利用分子链间的疏水作用形成壳聚糖水凝胶的方法;而在化学交联法部分介绍了合成壳聚糖水凝胶的化学手段,包括交联剂、光照辐射和酶的使用。继而概述了壳聚糖水凝胶在药物缓释应用方面的研究进展,包括温度、pH值和电场响应的药物控释体系。最后展望了壳聚糖水凝胶未来的发展前景。 相似文献
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Porosity and Corrosion Properties of Electrolyte Plasma Coatings on Magnesium Alloys 总被引:1,自引:0,他引:1
It is shown that oxide-ceramic coatings on magnesium alloys are, in general, characterized by high corrosion resistance depending on the porosity of the coating. The surface topology of oxide-ceramic coatings on IMV2 and VMD10 alloys is studied to reveal discontinuities by using special procedures of immersion and electrochemical deposition. Craters detected as a specific feature of the topology of the coatings and not always through and, in this case, they do not affect the corrosion resistance of the alloys. Isolated pores are formed, most often around the craters, in the process of oxidation under the action of high thermal stresses. On the basis of the comparative analysis of various materials and corrosive media, it is possible to make a conclusion that the corrosion resistance of magnesium alloys with oxide-ceramic coatings in acid media is mainly determined by the chemical composition of the alloy. At the same time, in neutral media, it is determined by the porosity of the coatings.__________Published in Fizyko-Khimichna Mekhanika Materialiv, Vol. 40, No. 5, pp. 13–17, September–October, 2004. 相似文献
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Thirumala Govender Cassim M. Dangor Dushendra J. Chetty 《Drug development and industrial pharmacy》1995,21(11):1303-1322
The air suspension technique was employed to prepare controlled release pellets of Salbutamol (as the sulphate). The aim of the present study was to determine the influence of various film coating additives on the release characteristics and surface morphology features of salbutamol sulphate pellets coated with EudragitR RS30D which is the aqueous dispersion of a polymer synthesised from acrylic and methacrylic acid esters. Surface morphology features, which were examined using Scanning Electron Microscopy, revealed that triethyl citrate (plasticiser) was essential for the coalescence of polymeric membranes around the drug-loaded spheres. Higher concentrations (12.5%) of triethyl citrate displayed a more uniform and continuous polymer film resulting in a slower in vitro drug release. Micrographs of the cross-sections of pellets with higher concentrations of EudragitR RS30D indicated the formation of thicker polymer membranes which accounted for the slower drug release rates. Hydroxypropyl methylcellulose (HPMC) inclusion in the polymer film coating increased salbutamol release rates due to its hydrophilic nature which promoted the formation of pores and cracks on the polymer films. A slower in vitro release of salbutamol was observed with higher concentrations of the hydrophobic anti-tackiness agent, magnesium stearate. The addition of salbutamol sulphate powder to the polymer dispersion enhanced drug release rates due to increased film permeability. Polyethylene glycol 200 (PEG 200) resulted in an increased in vitro drug release due to both its water soluble nature as well as impairment of film formation attributed to too high a plasticiser content in the coating formulation. As compared to polyethylene glycol 300 (PEG 300) as a plasticiser, triethyl citrate retarded drug release to a greater extent and formed more homogeneous and compact polymer films. The moisture content of PEG 300 plasticised pellets showed a 0.6% increase in moisture content while triethyl citrate plasticised pellets displayed a loss of 0.01% moisture 8 weeks after storage at room temperature. 相似文献
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镁及其合金表面防护性涂层国外研究进展 总被引:21,自引:4,他引:21
综述了近年来国外镁及其合金表面防护性涂层的研究进展,其中包括化学转化涂层、阳极氧化膜层、镀层(电镀、化学镀)、扩散膜层、激光表面合金改性层、气相沉积层及有机涂层等在镁合金基体上的应用情况,分析了其各自的利弊,并对镁合金表面防护技术的发展方向进行了展望. 相似文献
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Preparation and Preliminary Evaluation of Eudragit RL and RS Pseudolatices for Controlled Drug Release 总被引:1,自引:0,他引:1
Rong-Kun Chang James C. Price Charles Hsiao 《Drug development and industrial pharmacy》1989,15(3):361-372
Eudragit RL and RS pseudolatices were prepared by the solvent change technique, which consisted of dissolving the polymer in a water miscible organic solvent or in a mixed water miscible organic solvent system, followed by dispersian in deionized water under mild agitation. The organic solvent (s) was removed from the aqueous organic solution to leave a stable Eudragit latex.
Eudragit pseudolatex coated theophylline pellets were prepared in a fluidized-bed coating machine. The effects of polymer type and coating level, plasticizer concentration, and PH of the dissolution medium on drug release were investigated. The higher content of quaternary ammonium groups attached to the polymer backbone make the coatings produced from Eudragit RL too water sensitive; and hence unsuitable for controlling theophylline release. On the other hand, Eudragit RS films retarded theophylline release. On the other hand, Eudragit RS films retarded theophylline release over a wide pH range. Release of the drug was found to be a function of the polymer coating level, plasticizer concentration and dependent on pH of the dissolution medium. 相似文献
Eudragit pseudolatex coated theophylline pellets were prepared in a fluidized-bed coating machine. The effects of polymer type and coating level, plasticizer concentration, and PH of the dissolution medium on drug release were investigated. The higher content of quaternary ammonium groups attached to the polymer backbone make the coatings produced from Eudragit RL too water sensitive; and hence unsuitable for controlling theophylline release. On the other hand, Eudragit RS films retarded theophylline release. On the other hand, Eudragit RS films retarded theophylline release over a wide pH range. Release of the drug was found to be a function of the polymer coating level, plasticizer concentration and dependent on pH of the dissolution medium. 相似文献