基于肿瘤微环境的纳米靶向载体研究进展

目的:为纳米靶向载体研制提供参考。方法:以"肿瘤微环境""纳米靶向载体""靶向治疗""pH sensitive""Enzyme responsive""Redox responsive"等为关键词,组合查询2005-2016年在Pub Med、Elsevier、Springer Link、中国知网、万方、维普等数据库中的相关文献,对肿瘤组织微环境的特点和肿瘤微环境响应性纳米载药系统研究进行综述。结果与结论:共检索到相关文献235篇,其中有效文献39篇。肿瘤组织微环境主要特点包括微酸性、酶代谢异常、细胞内外存在还原性差异、存在影响肿瘤血管生成的因子和信号通路等。基于上述特点,分别研究出基于肿瘤滞留效应设计的纳米载体、pH响应型纳米载体、还原响应型纳米载体、酶响应型纳米载体、温度响应型纳米载体。与这些单响应载体比较,肿瘤微环境多重刺激响应型纳米载体更能充分发挥不同肿瘤微环境响应性物质之间的特点,对实现药物的特异性递送更有意义,这也将是今后的主要研究热点。     

还原响应型药物载体的研究进展

还原响应型药物载体以其高效快速释放药物、毒副作用小、可生物降解的优良特性,逐渐成为药物载体领域研究的热点,也是最具临床应用潜力的智能药物载体之一。本文综述了还原响应型药物载体研究的最新进展,包括还原响应的药物、基因与载体的偶联物及还原响应的纳米聚合物胶束、纳米囊泡、纳米中空微球、纳米脂质体等的合成和药物释放的机制以及各类载体的优缺点,为其在药剂学中的进一步应用提供理论依据。     

刺激响应型纳米载体用于克服肿瘤多药耐药的研究进展

摘要：多药耐药（MDR）是导致化疗失败的主要原因。刺激响应型纳米载体可响应于内源性刺激（耐药肿瘤微环境:pH、氧化还原、酶）和外源性刺激（光、超声、磁场、热）按需释放药物,在治疗肿瘤MDR领域显示出光明的前景。本文总结了各种刺激响应型纳米载体的刺激响应原理、材料及优势,并介绍了刺激响应型纳米载体在肿瘤MDR中的应用,为其后续研究与开发提供一定的参考。     

用于药物载体的刺激响应性聚合物及微凝胶的研究进展

在癌症治疗中,目前传统的化疗都是应用一些小分子制剂,不但能杀死肿瘤细胞,对正常的组织也会产生危害。因此,人们发展了一系列药物载体,在其表面连接一些靶向基团,可以特异性的识别并进入到肿瘤细胞内。除了这种基于主动靶向的药物载体,另外一类利用被动靶向的药物载体也越来越受到人们重视。为了使进入肿瘤部位的药物能够快速可控释放,人们发展了一系列刺激响应性高分子,利用肿瘤部位环境的不同而释放药物。常见的刺激响应性聚合物［1-3］包括：温度、pH、氧化还原以及光响应性的聚合物等,其中温度和酸敏感的聚合物是研究最为广泛的药物载体。这类聚合物载体包裹药物,在血液循环中比较稳定,当进入的到肿瘤组织中后,由于一些外部刺激,使聚合物解散,其中包裹的药物被迅速释放出来。此外,刺激响应性聚合物微凝胶在作为药物载体的方面的应用也越来越受到人们重视。下面主要介绍一下各种刺激响应性聚合物及微凝胶在药物传递方面的研究进展。     

纳米载药系统逆转肿瘤多药耐药的研究进展

目的:介绍纳米载药系统在逆转肿瘤多药耐药(MDR)方面的研究进展。方法:查阅近年来的相关文献,对纳米载体的特点,逆转MDR的机制及其在此领域的应用进行综述。结果:纳米技术可以使药物通过主动或被动靶向作用,更多地被肿瘤细胞摄取而逆转MDR。纳米载药系统还可以作为RNA的载体,通过基因干扰技术逆转肿瘤的MDR。结论:与单一功能和组成的载药系统相比,多功能或药物联用的纳米载药系统在逆转MDR方面更具优势。     

温敏聚合物自组装纳米粒子在抗肿瘤药物递送中的应用

作为抗肿瘤治疗的主要手段,化疗最大的缺陷在于化疗药物缺乏肿瘤靶向性,易对正常组织产生高毒性,并导致治疗效果不理想。为了解决这一问题,越来越多的聚合物纳米载体被用于递送抗肿瘤药物,包括对温度刺激能作出响应的温敏聚合物自组装纳米载体。笔者综述了近年来温敏聚合物自组装载体及其纳米粒子的研究进展,并介绍了其在抗肿瘤药物递送中的应用。     

刺激响应型经皮给药系统的研究进展

刺激响应型经皮给药系统可实现药物的特异性释放,提高药物的利用率。按照刺激方式的不同可将该类制剂分为内源性刺激响应型、外源性刺激响应型和联合刺激响应型经皮给药系统。其中,内源性刺激响应型经皮给药系统可通过载体材料对病变部位温度、pH等改变作出特异性响应,从而将药物递送至靶部位;外源性刺激响应型经皮给药系统可利用光、热、磁、电等外部刺激使载体材料发生相变,进而实现药物的递送;联合刺激响应型经皮给药系统则是结合2种或2种以上的刺激响应型经皮给药系统,如温度-pH双响应型给药系统等。目前,刺激响应型经皮给药系统的相关研究多处于实验阶段,未来还需更深层次的稳定性、毒性及皮肤刺激性评估,为临床应用奠定理论基础。     

纳米药物和纳米载体系统

阐明了纳米技术在药剂学领域中的现状，综述了国内外纳米药物和纳米载体的发展，介绍了纳米药物与纳米载体的尺寸范围、主要类型及其应用、制备技术、载药方法、表面修饰的意义及其在促进药物溶解、改善吸收、提高靶向性等方面的作用和机制，指出了纳米载体在生物大分子药物传输中的潜在应用前景。     

靶向释放智能纳米载体的研究进展

随着材料科学的进步,智能纳米载体在药物和基因靶向治疗方面取得了巨大的研究进展。智能纳米载体被化学信号、温度、pH等"触发器"激发后,能在特定部位响应性地释放药物或基因。该文从智能纳米载体的定义,不同类型靶向释放的智能纳米载体在药物和基因中的研究进展,靶向释放的智能纳米载体的不足及发展前景等方面进行综述。     

聚合物胶束在肿瘤治疗中的研究进展

聚合物胶束在肿瘤治疗方面具有高效、长效及高载药量等优势.本文简单比较了聚合物胶束与其它纳米级药物载体(如高分子直接键合药物、树枝状聚合物、脂质体)在临床应用上的优缺点.综述了聚合物胶束在肿瘤主动靶向性、环境刺激响应释药及医学成像等方面的研究进展.     

Passive and active tumour targeting with nanocarriers

Nanocarriers can penetrate the tumour vasculature through its leaky endothelium and, in this way, accumulate in several solid tumours. This is called the enhanced permeation and retention (EPR) effect. Together with nanocarriers whose surface is tailored for prolonged blood circulation times, the concept is referred to as passive targeting. Targeting ligands, which bind to specific receptors on the tumour cells and endothelium, can be attached on the nanocarrier surface. This active targeting increases the selectivity of the delivery of drugs. Passive and active drug targeting with nanocarriers to tumours reduce toxic side-effects, increase efficacy, and enhance delivery of poorly soluble or sensitive therapeutic molecules. In this review, currently studied and used passive and active targeting strategies in cancer therapy are presented.     

纳米载体提高难溶性药物口服生物利用度的研究进展

纳米载体是药剂学备受关注的研究领域,作为一类新型给药系统,它能显著提高难溶性药物的溶解度、生物利用度和稳定性,且具有明显的缓释作用,因此得到了广泛的应用。目前常用于提高难溶性药物口服生物利用度的纳米载体有纳米脂质体、固体脂质纳米粒、纳米胶束、和纳米结晶等,它们的粒径、表面性质及其释药环境等是影响纳米载体药物口服吸收的主要因素。本文对纳米载体提高难溶性药物口服生物利用度的研究进展作一综述。     

Polymeric nanocarriers as stimuli-responsive systems for targeted tumor (cancer) therapy: Recent advances in drug delivery

In the last decade, considerable attention has been devoted to the use of biodegradable polymeric materials as potential drug delivery carriers. However, bioavailability and drug release at the disease site remain uncontrollable even with the use of polymeric nanocarriers. To address this issue, successful methodologies have been developed to synthesize polymeric nanocarriers incorporated with regions exhibiting a response to stimuli such as redox potential, temperature, pH, and light. The resultant stimuli-responsive polymeric nanocarriers have shown tremendous promise in drug delivery applications, owing to their ability to enhance the bioavailability of drugs at the disease site. In such systems, drug release is controlled in response to specific stimuli, either exogenous or endogenous. This review reports recent advances in the design of stimuli-responsive nanocarriers for drug delivery in cancer therapy. In particular, the synthetic methodologies investigated to date to introduce different types of stimuli-responsive elements within the biomaterials are described. The sufficient understanding of these stimuli-responsive nanocarriers will allow the development of a better drug delivery system that will allow us to solve the challenges encountered in targeted cancer therapy.     

Stimuli-responsive polymeric nanocarriers for the controlled transport of active compounds: concepts and applications

The use of polymeric nanocarriers to transport active compounds like small-molecular drugs, peptides, or genes found an increased attention throughout the different fields of natural sciences. Not only that these nanocarriers enhance the properties of already existing drugs in terms of solubility, bioavailability, and prolonged circulation times, furthermore they can be tailor-made in such a manner that they selectively release their cargo at the desired site of action. For the triggered release, these so-called smart drug delivery systems are designed to react on certain stimuli like pH, temperature, redox potential, enzymes, light, and ultrasound. Some of these stimuli are naturally occurring in vivo, for example the difference in pH in different cellular compartments while others are caused by the disease, which is to be treated, like differences in pH and temperature in some tumor tissues. Other external applied stimuli, like light and ultrasound, allow the temporal and spatial control of the release, since they are not triggered by any biological event. This review gives a brief overview about some types of stimuli-responsive nanocarriers with the main focus on organic polymer-based systems. Furthermore, the different stimuli and the design of corresponding responsive nanocarriers will be discussed with the help of selected examples from the literature.     

Engineered PLGA nanoparticles: an emerging delivery tool in cancer therapeutics

Nanocarriers formulated with the US Food and Drug Administration-approved biocompatible and biodegradable polymer poly(lactic-co-glycolic acid) (PLGA) are being widely explored for the controlled delivery of therapeutic drugs, proteins, peptides, oligonucleotides, and genes. Surface functionalization of PLGA nanoparticles has paved the way to a variety of engineered PLGA-based nanocarriers, which, depending on reticular requirements, can demonstrate a wide variety of combined properties and functions such as prolonged residence time in blood circulation, enhanced oral bioavailability, site-specific drug delivery, and tailored release characteristics. The present review highlights the recent leaps in PLGA-based nanotechnology with a particular focus on cancer therapeutics. Starting with a brief introduction to cancer nanotechnology, we then discuss developmental aspects and the in vitro and in vivo efficacy of PLGA-based nanocarriers in terms of targeted drug or gene delivery. The main objective of this review is to convey information about the state of art and to critically address the limitations and the need for further progress and clinical developments in this emerging technology.     

细胞膜仿生纳米载体的制备及应用研究进展

由有机或无机纳米材料制备的药物载体系统广泛用于药物靶向递送和疾病的诊断治疗研究。但其存在靶向性差、体内循环时间短、生物相容性欠佳亟需提高等问题。仿生纳米药物系统是以不同种类的细胞膜修饰纳米载体,利用内源性的细胞膜提高载体的体内生物相容性、实现更精准的靶向、甚至由细胞自身的免疫原性产生免疫治疗作用。对细胞膜仿生纳米载体技术的原理、方法及其靶向机制和治疗作用作一综述,为新型给药系统研究提供思路。     

Use of prebiotics in oral delivery of bioactive compounds: a nanotechnology perspective

The oral route is considered the most patient-convenient means of drug administration. In recent years there has been a tendency to employ smart carrier systems that enable controlled or timed release of a bioactive material, thereby providing a better dosing pattern and minimizing side effects. Nano-encapsulation systems (nanocarriers) offer important advantages over conventional drug delivery techniques. Nanocarriers can protect the drug from chemical/enzymatic degradation and enhance bioavailability. Prebiotics are ideal ingredients for the nano-encapsulation and oral drug delivery due to their natural ability to protect the encapsulated compound in the upper gasterointestinal (GI) tract. Here the potential of prebiotics for oral delivery of drugs and other bioactives is reviewed.     

纳米载体在非酒精性脂肪肝药物治疗中的研究进展

非酒精性脂肪肝（non-alcohol fatty liver disease，NAFLD）已成为当前全球最常见的肝病之一，临床表现为肝脂肪变性，并逐步恶化为非酒精性脂肪肝炎（nonalcoholic steatohepatitis，NASH）、肝硬化、肝癌等末期肝病。目前治疗NAFLD的药物主要包括保肝药物、胰岛素增敏剂、降脂药、抗氧化剂等，但治疗效果尚未满足要求。纳米载体是纳米医学的重要组成部分，具有增加药物溶解性、控制药物释放、促进口服吸收、提高药物治疗效果和降低药物毒性等优势，在NAFLD药物治疗中具有较大的应用潜力，有待深入研究。     

Functionalized Graphene Oxide as Drug Delivery Systems for Platinum Anticancer Drugs

Graphene Oxide, prepared by the modified Hummer's method, was modified with a series of high polymers (polyethyleneimine, polyethylene glycol, chitosan) and Folic Acid for the delivery of platinum anticancer drugs including Cisplatin, Carboplatin, Oxaliplatin and Eptaplatin. Nanocarriers were successfully prepared and characterized by Fourier transform infrared spectroscopy, X-ray diffraction and scanning electron microscope. Measurement of drug loading efficiency showed that these nanocarriers had the ability for effective delivery of the platinum anticancer drugs. The Maximum loading ratios of Cisplatin, Carboplatin, Oxaliplatin and Eptaplatin were 25.72, 161.08, 345.21 and 67.80 μg/mg. Drug release experiments in the acid environment showed that the cumulative release rate of platinum anticancer drugs from nanocarriers was higher than that in the neutral environment. The cumulative release of all three nanocarriers in the acid environment reached above 60%. In vitro cytotoxicity assay showed that those nanocarriers had a low toxicity. The cell viability rates were above 80% for all three nanocarriers. Investigation of the anticancer activity in vitro showed that those drug delivery systems had the ability to inhibit the growth of the SKOV3 cell line. These results showed that those nanocarriers were suitable for the delivery of platinum anticancer drugs. Providing preliminary advice on the potential application of the combination of platinum anticancer drugs and the functionalized Graphene Oxide nanocarriers.     

Cancer chemotherapy with lipid-based nanocarriers

Nanotechnology has a profound effect on many areas of scientific research. Having grown exponentially, the focus of nanotechnology has been on therapeutic activity, such as cancer treatment. Lipid-based nanocarriers have attracted increasing scientific and commercial attention in the last few years as alternative carriers for the delivery of anticancer drugs. Lipid-based nanocarriers have played significant roles in the formulation of anticancer drugs to improve therapeutics. Shortcomings frequently encountered with anticancer compounds, such as poor solubility, normal tissue toxicity, poor specificity and stability, as well as the high incidence rate of drug resistance, are expected to be overcome through use of lipid-based nanocarriers. In this review, the advantages and methods of using nanocarriers to improve cancer treatment efficiency will be discussed. In addition, types of lipid-based nanocarriers are presented and hotspots in research are highlighted. It is anticipated that, in the near future, lipid-based nanocarriers will be further improved to deliver cytotoxic anticancer compounds in a more efficient, specific and safe manner.