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新型壳聚糖纳米球用于紫杉醇的靶向给药
Alternative TitleTargeted delivery of paclitaxel by chitosan-based nanoparticles
吕丕平
Subtype博士
Thesis Advisor马光辉
2013-05-01
Degree Grantor中国科学院研究生院
Degree Discipline生物化工
Keyword紫杉醇   壳聚糖   纳米球   靶向输送
Abstract紫杉醇(PTX)的难溶问题限制了其在临床上的应用。为了提高PTX的水溶性,解决目前临床注射制剂Taxol?存在的严重毒副作用问题,科研人员转向新型制剂的研究,包括制成脂质体、聚合物胶束和聚合物纳米球等。其中,可生物降解聚合物纳米球备受关注。本论文针对制备载PTX纳米球过程中存在的药物溶出慢、载药率低、批次间重复性差、生物利用率低及靶向能力差等问题,选择亲水性材料壳聚糖作为载体材料,设计出新型口服和注射用纳米制剂,用于肿瘤的靶向治疗。论文的主要研究内容如下: 1. PTX的装载及其口服纳米制剂的开发。亲水性壳聚糖纳米球无法实现对难溶性药物PTX的直接装载,为了解决这一问题,本论文首先选用O/W/O型复乳液法,通过优化制备条件,并结合程序升温固化技术实现了对PTX纳米晶的原位装载,极大提高了纳米球对紫杉醇的载药率(>35%)。利用本实验室开发的快速膜乳化技术控制了纳米球粒径的均一性(PDI<0.1),实现了批次间的可重复性。在此基础上,进一步在材料基质中复配其阳离子衍生物季铵化壳聚糖,制备出了具有丰富正电荷(+21.02 mV)的多孔载药纳米球(HNP:PTX),其多孔结构(13.98 nm)加快了药物的释放,纳米球表面的正电荷促进了小肠吸收和肿瘤细胞的摄取。HNP:PTX经口服吸收后可通过肿瘤的EPR效应将药物递送至肿瘤部位。基于以上优势,所构建的口服制剂展现出较临床制剂Taxol?有更好的抑瘤效果和更低的毒副作用。 2. 口服PTX/siRNA复合纳米给药系统的构建。在实现对化疗药物PTX成功装载的基础上,我们利用季铵化壳聚糖纳米球特有的多孔结构及丰富的正电荷,进一步装载了siRNA(用于抑制端粒酶反转录酶基因 表达)(HNP:siRNA/PTX)。结果显示,外层包裹的季铵化壳聚糖维持了其原有的正电性(+32.16 mV),提高了药物的口服生物利用度,而且还避免了siRNA在体液/血液和胞内溶酶体的降解。相比于单独的HNP:PTX,HNP:siRNA/PTX给药组展示出更显著的抑瘤效果。特别地,HNP:siRNA/PTX不仅能将两种药物同时递送至同一肿瘤细胞,集中了两种药物的“火力”,而且还提高了肿瘤部位的药物浓度,因此展现出较传统鸡尾酒混合疗法(HNP:siRNA+HNP:PTX)更显著的协同抑瘤效果。 3. 注射用PTX长循环靶向制剂的开发。首先通过在壳聚糖分子中-OH位引入羧基制得O-羧化壳聚糖(CMC),保护了分子中原有的-NH2。以O-羧化壳聚糖为基质制备出了表面富有羧基的多孔载药纳米球(CNP),继而通过具有异端双官能团的PEG链将肿瘤靶向配体RGD肽偶联至PEG链末端,成功制得了装载PTX的纳米球(RGD-PEG-CNP:PTX)。与未修饰的CNP相比,PEG化纳米球不仅能够提高其体液稳定性,而且能够显著延长其在血液中的循环周期(t1/2(CNP) = 8 h, t1/2(PEG-CNP) = 30 h)。RGD肽的嫁接进一步提高了载药纳米球与肿瘤细胞的亲和力,使肿瘤细胞对载药纳米球的摄取量增加一倍,实现了主动靶向的目的。基于以上优势,该靶向制剂的抑瘤效果远优于临床制剂Taxol?。
Other AbstractClinical application of paclitaxel (PTX) has been limited because of its poor solubility in aqueous media. To enhance the solubility of PTX and reduce the current serious side effects associated with Taxol?, researchers are turning their attention to the development of new pharmaceutical preparation, including liposome, polymeric micelles, nanoparticles, and so on. Among these formulations, nanoparticles prepared by biodegradable polymer have attracted a growing interest due to many advantages, such as prolonged blood circulation time, stable plasma drug concentration, targeted drug delivery, and expanded administration route. In this study, we developed a series of novel chitosan-based PTX carriers and systematically evaluated their antitumor efficacy.In detail, this thesis mainly included the following three parts: 1. PTX-loaded chitosan nanoparticles with uniform-size were prepared by SPG membrane emulsification technique together with chemical crosslinking method. First, PTX was successfully encapsulated into chitosan nanoparticles as nanocrystallite form by O/W/O double emulsion and temperature-programmed solidification methods, enhancing the loading efficiency (LE>35%) and encapsulation efficiency (EE>80%). On this basis, we further developed an oral formulation of PTX by adding N-((2-hydroxy-3-trimethylammonium) propyl) chitosan chloride (HTCC) into nanoparticles matrix, which endowed nanoparticles with porous structure (pore size: 13.98 nm) and abundant positive charges (+21.02 mV). The hydrophilicity and porous structure of the obtained nanoparticles (HTCC-NP:PTX) accelerated their degradation and improved drug release. The presence of positive charges enhanced the intestinal permeability and tumor cell internalization. Additionally, The HTCC-NP could deliver PTX to tumor site via the EPR effect after oral administration. Consequently, HTCC-NP:PTX exhibited better therapeutic effect and caused lower side effects in comparison with Taxol?. 2. Having successfully developed oral formulation of PTX, we further achieved co-encapsulation of telomerase reverse transcriptase (TERT) siRNA using the porous structure and the positive charge of HTCC-NP (HNP). The outer coating of HTCC not only protected siRNA from enzymatic degradation, but also improved siRNA permeability in intestine tract. Compared with HNP:PTX alone, the obtained “two-in-one” nano-complex (HNP:siRNA/PTX) exhibited higher antitumor efficacy. Particularly, HNP:siRNA/PTX could simultaneously ferry siRNA and PTX into tumor cells and increase drug concentration, which, in particular, was much more effective in tumor suppression than that of traditional cocktail therapy (HNP:siRNA+HNP:PTX). 3. In addition to oral delivery system, we also developed a tumor targeting intravenous delivery system for PTX by PEGylated O-carboxymethyl-chitosan (CMC) nanoparticles (CNP) grafted with cyclic Arg-Gly-Asp (RGD) peptide. Compared with the pristine nanoparticles, PEGylated nanoparticles remained for a longer time in the blood circulation after intravenous administration (t1/2(CNP) = 8 h, t1/2(PEG-CNP) = 30 h). Graft of cyclic RGD peptide at the terminal of PEG chain further endowed these nanoparticles with higher affinity to tumor cells, enhancing tumor cell internalization. These outstanding properties enabled as-designed nanodevice to exhibit a greater tumor growth inhibition effect and much lower side effects over the commercial formulation Taxol?.
Pages158
Language中文
Document Type学位论文
Identifierhttp://ir.ipe.ac.cn/handle/122111/8255
Collection研究所(批量导入)
Recommended Citation
GB/T 7714
吕丕平. 新型壳聚糖纳米球用于紫杉醇的靶向给药[D]. 中国科学院研究生院,2013.
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