磁性靶向药物的研究概况

磁性药物指将药物和磁性物质共同包裹于聚合物载体中制成的磁性靶向给药系统(MTDDS),利用外加磁场将药物在体内定向移动和定位集中,在磁场区内释放,从而起到靶区局部浓集作用或靶区截流作用.综述磁性靶向药物的组成及分类.对磁性靶向给药系统现存问题进行总结并对前景进行展望.     

靶向输运磁性载药颗粒的研究进展

介绍了目前磁性药物靶向治疗的进展,主要包括纳米磁性药物载体的性质,磁靶向系统的磁场装置,靶向性研究,动力学模拟,以及对磁性靶向治疗的前景与展望。     

阿霉素磁靶向药物制剂研究进展

磁靶向给药系统在肿瘤治疗方面已越来越受到关注,其先将药物负载到磁性聚合物微球上,然后通过外加磁场作用使载药微球定位至病灶部位,药物通过脱附作用或载体降解等途径在病灶部位释放产生疗效。该文在磁靶向制剂的发展背景基础上,探讨阿霉素磁性靶向制剂的发展及研究概况,并对其发展前景进行展望。     

磁性热敏脂质体的研究进展

磁性热敏脂质体是近年来兴起的一种新型靶向药物载体,它可以在外加磁场的作用下随血液循环聚集到靶器官,在不加磁场或正常体温条件下应使包裹在脂质体中的药物缓慢、平稳释放并起到药品储库作用;而在体外交变磁场作用下产热达到热敏脂质体相变温度而控制包裹在脂质体中的药物迅速释放,以达到在肿瘤组织靶向、多次和脉冲式给药的效果。与普通脂质体相比,磁性热敏脂质体具有更强的组织靶向性和控释特性。本文综述了磁性热敏脂质体的制备、磁定位靶向性和热敏释药性。     

磁性纳米粒子及其在生物医学中的应用进展

磁性纳米粒子由于独有的特性在医药中有着多种用途。其中最独特的特性是磁响应性,利用这一特性磁性粒子被应用于药物载体、磁性分离和细胞的分选。近年来由于其可作为对比剂用于磁共振成像、作为热疗介质用于癌症热疗,并且可应用于磁力组织工程而引起研究者们的广泛关注。具有独特特性的功能性纳米磁性粒子的这些应用将更进一步促进医药生物技术的发展。该综述主要介绍磁性纳米粒子在磁性分离与磁性转染、磁力组织工程、药物靶向载体、核磁共振、肿瘤热疗中的应用。     

磁性载体在药物传递系统中的应用

靶向制剂又称靶向给药系统,被称为第四代给药方法,是指载体将药物通过局部给药或全身血液循环而选择性地浓集定位于靶组织、靶器官、靶细胞或细胞内结构的给药系统.靶向给药系统从方法学上大体可分为三类:被动靶向药物传递系统、主动靶向药物传递系统和物理化学靶向传递系统[1].     

磁性靶向载药微球研究进展

磁性靶向药物治疗具有疗效高、用药量少、不良反应小等特点,是近年来发展的一种新的治疗肿瘤的方法。该文主要介绍了靶向给药治疗的机制及磁性靶向载药微球的构成和研究进展,并对其发展前景进行了展望。     

磁性脂质体的制备及其抗癌作用的研究概况

1965年,英国学者 Banghan等 [1]将磷脂悬浮于水中首次得到了脂质体; 1970年, Sessa等提出脂质体可作为药物载体的见解以后,引起了各国学者的关注 [2～ 4].磁性靶向过程是血管内血流对微粒产生的力和磁铁产生的磁力的竞争过程,当磁力大于动脉线形血流速率( 0. 05cm/s)时,磁性脂质体被截留在靶部位.磁性脂质体是掺入磁性物质制成的脂质体,当其进入体内后,利用外磁场的效应引导药物在体内定向移动后靶向给药,使其靶向性和专一性更强,诊断、治疗更准确.     

纳米磁靶向药物载体在肿瘤治疗中的研究进展

纳米磁靶向药物载体是靶向治疗的一种载体形式,粒径在1~1000nm之间,它借助于磁场使药物载体聚集在靶部位,平稳释放药物,提高靶部位药物浓度,增强治疗效果,同时减少其它部位的药物分布,降低药物的毒副作用。该药物载体一方面具有磁靶向药物载体的一般特性,结合固定磁场或交变磁场而具有靶向性或产热性,携带化疗药物或放射性物质,能杀灭肿瘤细胞;另一方面粒径达到纳米级,并具有体内长循环等特性。本文介绍纳米磁靶向药物载体在肿瘤治疗(包括化疗、放疗、热疗等)领域的研究进展。1纳米磁靶向药物载体在肿瘤化疗中的应用纳米磁靶向药物载体能携…     

磁性纳米粒及其在药物传输体系中的应用

综述磁性纳米粒的特性、种类、制备及其表面修饰以及作为药物传输体系载体的应用研究。磁性纳米粒用作药物载体的优势在于,除了可提高药物的靶向性,降低其毒副作用,还因具磁学性质而能发挥多功能治疗作用。     

Magnetic drug targeting. II. targeted drug transport by magnetic microp articles: factors influencing therapeutic effect

The kinetic aspects of magnetically targeted drug transport are considered. The influence of the magnetic drug carrier properties, the transported drug and the target parameters on the biological effect of the drug is discussed. The mathematical model reflecting the mass-transfer processes in a blood flow system is used for the estimation of the influence of these factors on the therapeutic effect of the drug delivered to the target. The character of the effect of drug release parameters, rate of drug released inactivation and the intensity of carrier capture in the liver is shown. Mathematical modelling of magnetically targeted drug kinetics allows possibilities for prognosis of drug effects.     

Magnetic drug targeting. I. in vivo kinetics of radiolabelled magnetic drug carriers

The localization of intravenously injected magnetic drug carriers in the injured area of an organism is complicated by carrier capture in the liver and other normal organs and tissues. The in vivo kinetics of radiolabeled magnetically targeted drug carriers has been studied; one-exponent kinetics is shown. A mathematical model of carrier capture in animal tissues based on capture mechanism and mass-transfer processes in the circulating blood is proposed. Biodistribution and capture intensity of the carbohydrate-and albumin-coated magnetic microparticles of different sizes have been compared. For detecting small differences in the magnetic carriers‘ biokinetics, which are normally obscured by individual differences of the animals, a “one-animal” biokinetic test based on the proposed model proved to be effective.     

Effect of carrier dose on the multiple tissue disposition of doxorubicin hydrochloride administered via magnetic albumin microspheres in rats

The effect of carrier dose on the multiple tissue disposition of doxorubicin hydrochloride has been investigated in rats. The drug was encapsulated in submicron magnetic albumin microspheres using a heat-denaturation technique. The rat tail was used as a target organ. Two groups of animals were administered 2.0 or 0.04 mg/kg of microsphere-entrapped drug via the ventral caudal artery, and the predefined tail target site was exposed to a 8000-G magnetic field for 30 min after dosing. In each group, the animals were sacrificed in triplicate over a 48-h period, and their various tissues were analyzed for drug concentration using reversed-phase ion-pair HPLC. The reduction in carrier dose was found to increase drug distribution as well as the targeting efficiency for the target tissue. The drug delivery to heart and liver was reduced. The significance of carrier dose in the targeted delivery of drugs is discussed.     

Receptor-mediated targeted drug or toxin delivery

The new approach to the treatment of cancer or to immunomodulation is drug targeting. Cellular uptake of drugs bound to a targeting carrier or to a targetable polymeric carrier is mostly restricted to receptor-mediated endocytosis. Factors that influence the efficiency of receptor-mediated uptake of targeted drug conjugate are the affinity of the targeting moieties, the affinity and nature of the target antigen, density of the target antigen, the epitope of the target antigen, the type of cell target, the rate of endocytosis, the route of internalization of the ligand-receptor complex, the ability of the drug or toxin to release from its targeted carrier, the ability of the drug or toxin to escape from a vesicular compartment into the cytosol, the affinity of the carrier to the drug and the concentration of the carrier. Targeted chemotherapy is also significantly influenced by the antigenic modulation and/or immunoselection of tumor cells. The binding of drug (toxin) to targetable polymeric carrier considerably decreases unwanted side toxicity.     

Develop a novel superparamagnetic nano-carrier for drug delivery to brain glioma

Abstract

Magnetic drug carrier has been employed in drug delivery for over 30 years. Modern nanotechnology has improved its efficiency dramatically by decreasing its diameter into nano-scale. It may help chemotherapeutic agents penetrate BBB and raise local drug concentration in brain, which is the ideal model for glioma treatment. In our study, magnetic carrier was fabricated with octadecyl quaternized caroxymethyl chitosan (OQCMC), hydrophobic Fe₃O₄ ferrofluid and cholesterol, which showed a uniform diameter of 20?nm under transmission electronic microscopy and superparamagnetic character in vibration sample magnetical measurement system. To investigate the efficacy of drug delivery, paclitaxel was used as loaded drug and analyzed by the HPLC. Results showed that magnetic carrier released drugs for more than 20?d in vitro and maintain the drug concentration above 0.4?μg/g for 16?h in rat brain after magnetic targeting. Drug concentration increased by 1–3 folds when delivered by carrier without magnetic targeting, and by 3–15 folds after magnetic targeting. Cellular study revealed that the magnetic carrier was clearly localized in the targeted cortex neural cells and U251-MG cell lines. These results showed that this magnetic carrier is capable of maintaining high drug concentration in magnetically targeted area and carrying drugs or genes into cells, which is potentially promising for local chemotherapy to brain tumors.     

透明质酸修饰的空腔靶向纳米载体制备及其体内外性能评价

目的： 制备具有pH响应性的透明质酸衍生物修饰的主动靶向载药空腔纳米球载体,并进行相关性能测定。方法： 采用One-pot法制备空腔碳酸钙纳米球,并用透明质酸与壳聚糖的偶联物进行修饰,得到具有pH响应性的靶向给药载体;以阿霉素作为模型药物,对载体的粒径及Zeta电位、包封率、载药量及体外释放进行考察;以人肝癌HepG2细胞,通过MTT实验进行细胞毒性验证;以H22荷瘤小鼠为模型验证载体在体内及肿瘤部位的靶向性作用。结果： 所制备的靶向给药载体呈球状,平均粒径（376.8±12.4）nm,PDI为（0.295±0.080）,Zeta电位为（-45.1±0.3）mV,包封率（80.45±2.35）%及载药量（15.65±0.25）%;体外释放显示出此载体具有良好的pH响应性,且具有明显的缓释特征;细胞毒性实验证明了此载体具有低毒性;荷瘤小鼠实验证明了此载体具有良好的肝靶向和肝肿瘤靶向能力。结论： 成功制备了透明质酸衍生物修饰的碳酸钙空腔纳米球靶向给药载体,此载体具有良好肝癌靶向治疗的能力。     

Liposomes as targetable drug carriers

The general problem of targeted drug transport is critically reviewed and three principle components of targeted systems are discussed: the target, the vector molecule, and the carrier. Different systems of drug targeting are briefly described: local drug application, chemical modification of the drug molecule, physical targeting under the action of pH, temperature, or magnetic field. The idea of a vector molecule is discussed and different methods of vector molecule coupling with the drug are reviewed (direct coupling, coupling via spacer group or polymer molecule, etc.). It is shown that the most promising approach seems to be the use of a drug-containing microcontainer with the vector molecule immobilized on its outer surface. Different types of microcontainers are briefly described: microcapsules, cell hosts, and liposomes. The advantages of liposomes as drug containers are shown and the main problems of their use for drug targeting in vitro and in vivo conditions are discussed. One of the most important problems is the problem of vector molecule immobilization on liposome surfaces. The principle four different immobilization methods: adsorbtion, incorporation, covalent binding, and hydrophobic binding. Targeted liposome transport is described in model systems, cell cultures, and experimental animals. It is shown that targeted liposomes may release a drug via diffusion, lysis, or endocytosis by appropriate cells. The problems of targeted liposome technology and clinical application are analyzed.     

Preparation of poly epsilon-caprolactone nanoparticles containing magnetite for magnetic drug carrier

Magnetic poly epsilon-caprolactone (PCL) nanoparticles were prepared in a well shaped spherical form by the o/w emulsion method. The influence of some preparative variables on the size and surface property was investigated. Nanoparticles were smooth, well individualized and homogeneous in size. The presence of magnetite and its superparamagnetic characteristic were confirmed by transmission electron microscope (TEM), Fourier transform infrared spectroscopy (FT-IR) and vibrating sample magnetometer (VSM), respectively. The anti-cancer drug was encapsulated in the magnetic nanoparticle during preparation. A typical release behavior was observed for 30 days. In vitro experiment of magnetic susceptibility under external magnetic field demonstrated that the magnetic PCL nanoparticles have sufficient magnetic susceptibility for a potential magnetic drug carrier for targeted delivery.     

Magnetic systems for cancer immunotherapy

Immunotherapy is a rapidly developing area of cancer treatment due to its higher specificity and potential for greater efficacy than traditional therapies. Immune cell modulation through the administration of drugs, proteins, and cells can enhance antitumoral responses through pathways that may be otherwise inhibited in the presence of immunosuppressive tumors. Magnetic systems offer several advantages for improving the performance of immunotherapies, including increased spatiotemporal control over transport, release, and dosing of immunomodulatory drugs within the body, resulting in reduced off-target effects and improved efficacy. Compared to alternative methods for stimulating drug release such as light and pH, magnetic systems enable several distinct methods for programming immune responses. First, we discuss how magnetic hyperthermia can stimulate immune cells and trigger thermoresponsive drug release. Second, we summarize how magnetically targeted delivery of drug carriers can increase the accumulation of drugs in target sites. Third, we review how biomaterials can undergo magnetically driven structural changes to enable remote release of encapsulated drugs. Fourth, we describe the use of magnetic particles for targeted interactions with cellular receptors for promoting antitumor activity. Finally, we discuss translational considerations of these systems, such as toxicity, clinical compatibility, and future opportunities for improving cancer treatment.     

离子交换树脂在药剂学中的应用进展

离子交换树脂药物载体在给药系统中的应用由于具有很多优点而得到了人们的重视。目前在控释、透皮给药、定位给药、速溶、离子导入透皮、鼻腔、局部给药和掩盖药物苦味等方面都有很深入的研究，在缓控释给药中占有特殊的地位。综述了这一药物载体在给药系统和作用部位应用的新进展，并对其应用前景进行了展望。