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肿瘤细胞增殖速度快,肿瘤组织的供氧不足,肿瘤细胞代谢产生大量乳酸,导致肿瘤组织与体内正常组织器官相比pH值偏低。因此,利用不同组织中pH值的差异设计具有pH敏感的聚合物胶束载药系统,从而提高抗肿瘤药物的靶向性和治疗效果。本文主要从pH敏感聚合物胶束的类型和及其释药机制等方面概述了pH敏感聚合物胶束纳米给药系统的研究进展。 相似文献
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采用可逆加成-断裂链转移自由基聚合(RAFT)制备一种可生物降解的以腙键(hydrazone)连接的聚N-(2-羟丙基)甲基丙烯酰胺-腙键-聚己内酯(PHPMA-hyd-PCL)两亲性聚合物。运用核磁共振(1H NMR)对聚合物的结构进行了表征。采用透析法制备胶束,形成以聚HPMA为亲水壳层、聚己内酯为疏水内核、腙键为pH敏感基团的胶束。动态光散射(DLS)以及透射电镜(TEM)结果表明,聚合物胶束呈规整球形且分布均匀,平均粒径约为100 nm。以抗癌药物阿霉素作为模型药物模拟体外释放实验,结果表明负载阿霉素的PHPMA64-hyd-PCL80聚合物纳米胶束在pH=7.4的缓冲溶液中48 h累积释放率仅为16%,在缓冲溶液pH=5.0中24 h可以释放85%。在pH=5.0时,由于腙键的断裂,载药胶束显著溶胀增大,抗癌药物迅速从胶束中释放出来,证明该纳米胶束具有较好的药物促释能力。因此,该pH敏感胶束具有作为药物载体的良好潜能。 相似文献
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以葡聚糖为原料,采用反相微乳液技术制备了一种含有席夫碱结构的葡聚糖基水凝胶纳米微球作为载体,通过交联剂聚乙烯亚胺(PEI)的静电吸附作用对药物模型8-羟基芘-1,3,6-三磺酸三钠盐(HPTS)进行了包埋,利用FTIR、SEM和DLS等对微球的结构和形貌进行了表征。结果表明,这种葡聚糖纳米水凝胶载药前后均具有良好的球形结构,平均粒径分别在459和648 nm左右。载药效果及药物释放行为研究发现,该葡聚糖纳米水凝胶可对HPTS进行有效负载,且其释放行为具有明显的酸性环境敏感性,酸性越强,释放越快。含有席夫碱结构的葡聚糖纳米凝胶微球可作为pH敏感型载体应用于药物递送领域。 相似文献
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Pluronic嵌段共聚物胶束作为靶向药物载体 总被引:8,自引:2,他引:8
聚氧乙烯 聚氧丙烯 聚氧乙烯 (PEO PPO PEO)三嵌段共聚物 (商品名为Pluronics)在水溶液中能自发生成多分子聚集的胶束 ,这些胶束主要以疏水的PPO嵌段为内核 ,PEO嵌段环绕在外构成外壳 ,这种胶束可以有效地增溶油溶性药物。Pluronic嵌段共聚物无毒、无刺激、无免疫原性 ,胶束外壳的PEO嵌段能阻止血小板的聚集。胶束尺寸和病毒相仿 ,其大小适合在体内传输。初步尝试表明 ,胶束表面嵌上合适的抗体可以将增溶了模型药物的Pluronic胶束定向输送到动物脑部 ,从而提高了药效 ,降低了副作用。实验表明 ,Pluronic嵌段共聚物胶束可能成为将多种药物导向特定部位的有效载体。 相似文献
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基于糖尿病病理特点而设计的葡萄糖敏感性给药系统能够根据体内血糖浓度的变化而自主调节药物释放,从而有效地控制体内血糖浓度,极具应用前景。目前,葡萄糖敏感性给药系统主要为载有葡萄糖氧化酶、刀豆蛋白A和苯硼酸体系三种。本文综述了近些年来葡萄糖敏感性给药系统的研究及应用,为后期开发基于糖尿病理特点的智能给药系统的实验研究提供一些参考。 相似文献
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Network structures based on poly(lactic acid)(PLA) were prepared for use as drug carriers to improve the effectiveness of drug therapy. A prepolymer precursor, with low molecular weight (5148), as determined by Gel Permeation Chromatography (GPC), was prepared by polycondensation of poly(lactic acid) with hydrolyzed ?-caprolactone. A second step that is necessary to increase the molecular weight and build up a network structure with elastic properties involved further polycondensation with stoichiometric amount of 1,6-hexamethylene diisocyanate to finally obtain Poly(ester urethane) with a molecular weight of 25680. The physicomechanical properties of the resulting polymeric networks were evaluated and the one that found to exhibit the best combination of tensile strength (3.83 MPa) and elongation at break (646%) was selected for slow release applications. Propolis and Doxorubicin as bioactive materials were incorporated into the selected sample and shaped in the form of circular discs with 0.9 cm diameter and 0.4 cm thickness. The discs containing the bioactive materials were subjected to a buffer solution at pH 7.4, and the release rates of Propolis and Doxorubicin were measured spectrophotometrically and found to be 35 µg/L/day and 70 µg/L/day for Propolis and Doxorubicin, respectively over a prolonged time of 15 days. 相似文献
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在过去的几十年中,探索高效的微/纳米给药系统一直是药剂学领域的研究热点。不同的微/纳米颗粒已被用于药物输送的研究,以期实现有效靶向给药,最大限度地减少副作用,从而提高治疗效果。本文主要综述了微/纳米药物输送给药系统及在药物制剂领域应用。 相似文献
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《国际聚合物材料杂志》2012,61(18):978-987
Candesartan-g-polyethyleneimine-cis-1,2-cyclohexanedicarboxylic anhydride (CD-g-PEI-HHPA, CPH) polymer-drug conjugates based on charge-conversional delivery, enhanced buffering capacity, amidase-triggered drug release, and combined cancer chemotherapy strategies were successfully synthesized for simultaneous and effective codelivery of CD and paclitaxel (PTX) to treat cervical cancer. The CPH polymer-drug conjugates could self-assemble into core-shell structure micelle of around 100 nm in diameter with negative surface charge and were employed to load PTX to formulate binary drug delivery system. The CPH polymeric micelles could mediate quick endosomal escape and amidase-responsive drug-release manners. In vitro cytotoxicity and in vivo investigations confirmed CPH binary drug delivery system exerted strong antitumor efficacy. 相似文献
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聚乳酸及其共聚物由于其生物相容性和生物可降解性,被广泛应用于医药和生物学领域。文章就国内外对聚乳酸及其共聚物作为新型载药系统的研究,进行了归纳总结。旨在说明聚乳酸作为药物载体的优势和发展前景。 相似文献