Preparation and characterization of a biodegradable drug targeting system for anticancer drug delivery: microsphere-antibody conjugate

Targeted delivery of anticancer drugs is one of the most actively pursued goals in anticancer chemotherapy. A major disadvantage of anticancer drugs is their lack of selectivity for tumour tissue, which causes severe side effects and results in low cure rates. Any strategy by which a cytotoxic drug is targeted to the tumour, thus increasing the therapeutic index of the drug, is a way of improving cancer chemotherapy and minimizing systematic toxicity. This study covers the preparation of the gelatin microsphere (GM)-anti-bovine serum albumin (anti-BSA) conjugate for the development of a drug targeting approach for anticancer drug delivery. Microspheres of 5% (w/v) gelatin content were prepared by crosslinking with glutaraldehyde (GTA) at 0.05 and 0.50% (v/v) concentration. Microspheres were in the size range of 71-141?microm. The suitability of these microspheres as drug carriers for anticancer drug delivery was investigated in vitro by studying the release profiles of loaded methotrexate (MTX) and 5-fluorouracil (5-FU) and the cytotoxicities on cancer cell lines. The in vitro MTX release profiles (approximately 22-46% released in 24 h depending on the amount of GTA used) were much slower compared to 5-FU (approximately 42-91% released in 24 h). Both drugs demonstrated an initial fast release, which was followed by gradual, sustained drug release. The MTT cytotoxicity test results of GMs loaded with 5-FU and MTX showed approximately 54-70% and approximately 52-67% cytotoxicities in 4 days. In general, incorporation of MTX and 5-FU in microspheres enhanced the cytotoxic effect in a more prolonged manner compared to the free drugs. Gelatin micospheres were chemically conjugated to anti-BSA and the antigen-antibody activities were studied by immunofluorescence. Results indicated approximately 80% binding with conjugated anti-BSA and BSA-FITC. Based on their low cytotoxicity and the high antigen binding efficiencies, anti-BSA conjugated gelatin microspheres could be suitable targeted drug carrier systems for selective and long-term delivery of anticancer drugs to a specific body compartment (i.e. bladder cancer).     

Synthesis, characterization andin vitro evaluation of triptolide-lysozyme conjugate for renal targeting delivery of triptolide

A triptolide-lysozyme (TP-LZM) conjugate was synthesized to achieve renal specific delivery and to reduce the side effects of triptolide. Triptolide was coupled to lysozyme through succinic via an ester bond with an average coupling degree of 1 mol triptolide per 1 mol lysozyme. The lysozyme can specifically accumulate in the proximal tubular cells of the kidney, making it a potential carrier for targeting drugs to the kidney. The structure of triptolide succinate (TPS) was confirmed by IR, 1H-NMR, MS and UV. The concentrations of triptolide in various samples were determined by reversed-phase high-performance liquid chromatography (HPLC). In this study, the physicochemical and stability profiles of TP-LZM under various conditions were investgated the stability and releasing profiles of triptolide-lysozyme (TP-LZM) under various conditions. In vitro release trails showed triptolide-lysozyme was relatively stable in plasma (less than 30% of free triptolide released) and could release triptolide quickly in lysosome (more than 80% of free triptolide released) at 37 degrees C for 24 h. In addition, the biological activities of the conjugate on normal rat kidney proximal tubular cells (NRK52E) were also tested. The conjugate can effectively reduce NO production in the medium of NRK52E induced by lipopolysaccharide (LPS) but with much lower toxicity. These studies suggest the possibility to promote curative effect and reduce its extra-renal toxicity of triptolide by TP-LZM conjugate.     

经鼻脑靶向递药系统的研究进展

鼻腔与脑在解剖生理上的独特联系使得鼻腔给药作为脑内递药途径成为可能.鼻腔给药作为脑靶向的途径之一,可有效地使通过其他给药途径不易透过血脑屏障的药物绕过血脑屏障到达脑部,为中枢神经系统疾病的治疗提供了一种极有发展前景的脑内递药途径.就鼻腔给药脑靶向的依据、影响因素、评价方法、剂型等方面对经鼻脑靶向递药系统的研究现状进行总结.     

靶向递释系统的研究进展

靶向递释系统(targeting drug delivery system,TDDS)能够选择性作用于病变部位,控制药物的分布与释放,提高药效和降低毒副作用,已成为癌症等疾病治疗领域的研究热点之一。本文综述了各类TDDS的机制、载体类型、制备技术和体内外靶向性,对近年来靶向递释系统的研究现状、未来产品研发与临床应用的可行性进行了探讨。     

经鼻脑靶向给药系统研究进展

由于血脑屏障的存在,血液中的药物难以进入中枢神经系统.近些年研究表明,经鼻腔给药后,药物可以绕过血脑屏障直接进入脑部,而且其对机体的损伤和副作用都较小,因此经鼻脑靶向给药系统不断受到更多人的关注.首先探讨了药物经鼻入脑的通路及机制,并针对鼻腔给药的不同影响因素提出了相应的优化方案,还介绍了脑靶向性的评价方法,为进一步研究鼻脑靶向制剂提供了参考.     

脑靶向给药的主要方式及其应用

由于血脑屏障的存在，大脑给药受到了严格控制。为使药物更专一地靶向至大脑，科学家们采取了多种办法。本文综述了治疗大脑疾病的靶向给药系统的2种方式：基于化学方法和生物学方法的脑靶向给药系统，以及它们在治疗大脑疾病方面的应用，为脑部给药的研究提供了依据。     

Bacterial ghosts as a novel advanced targeting system for drug and DNA delivery

Although there are powerful drugs against infectious diseases and cancer on the market, delivery systems are needed to decrease serious toxic and noncurative side effects. In order to enhance compliance, several delivery systems such as polymeric micro- and nanoparticles, liposomal systems and erythrocyte ghosts have been developed. Bacterial ghosts representing novel advanced delivery and targeting vehicles suitable for the delivery of hydrophobic or water-soluble drugs, are the main focus of this review. They are useful nonliving carriers, as they can carry different active substances in more than one cellular location separately and simultaneously. Bacterial ghosts combine excellent natural or engineered adhesion properties with versatile carrier functions for drugs, proteins and DNA plasmids or DNA minicircles. The simplicity of both bacterial ghost production and packaging of drugs and/or DNA makes them particularly suitable for the use as a delivery system. Further advantages of bacterial ghost delivery vehicles include high bioavailability and a long shelf life without the need of cold-chain storage due to the possibility to freeze-dry the material.     

Elastin-like polypeptides and their applications in anticancer drug delivery systems: a review

Abstract

Elastin-like polypeptides (ELPs) are large molecular weight biopolymers. They have been widely studied as macromolecular carriers for targeted delivery of drugs. The aim of the present article is to review the available information on ELPs (including our recent investigations), their properties, drug delivery applications to tumor sites and future perspectives. This review also provides information on the use of short synthetic ELPs for making ELP-drug conjugates, for targeted delivery of anticancer drugs. In the present review we also focus on the point that short ELPs can also be used for targeting anticancer drugs to tumor sites as they behave similar to long ELPs regarding their capacity to undergo inverse temperature transition (ITT) behavior.     

Synthesis and characterization of the tumor targeting mitoxantrone-insulin conjugate

Anticancer drugs have serious side effects arising from their poor malignant cells selectivity. Since insulin receptors highly express on the cytomembrane of some kind of tumor cells, using insulin as the vector was expected to reduce serious side effects of the drugs. The objective of this study was to evaluate the tumor targeting effect of the newly synthesized mitoxantrone-insulin conjugate (MIT-INS) with the drug loading of 11.68%. In vitro stability trials showed MIT-INS were stable in buffers with different pH (2-8) at 37 degrees C within 120 h (less than 3% of free MIT released), and were also stable in mouse plasma within 48 h (less than 1% of free MIT released). In vivo study on tumor-bearing mice showed that, compared with MIT [75.92 microg x h/g of the area under the concentration-time curve (AUC) and 86.85 h of mean residence time (MRT)], the conjugates had better tumor-targeting efficiency with enhanced tumor AUC of 126.53 microg x h/g and MTR of 151.95 h. The conjugate had much lower toxicity to most other tissues with targeting indexes (TIC) no larger than 0.3 besides good tumor targeting efficiency with TIC of 1.67. The results suggest the feasibility to promote the curative effect in cancer chemotherapy by using insulin as the vector of anti-cancer drugs.     

瘤内注射用阳离子型紫杉醇乳脂体的制备及体外性质评价

目的:制备适于瘤内给药的阳离子型紫杉醇乳脂体(PTX-CTAB-NES),并对其理化性质及细胞毒性进行评价。方法:采用溶剂蒸发法制备PTX-CTAB-NES,利用中心复合设计优化处方,透射电镜观察形态,纳米粒径仪测定粒径分布,XRD确证PTX在载体中的分散状态,HPLC法测定其包封率、载药量,透析法研究制剂的体外释药行为,并对其细胞毒性进行评价。结果:PTX-CTAB-NES呈类球形,可见明显指纹结构,平均粒径为94.0 nm,Zeta电位为+48.3 mV,包封率、载药量分别为98.0%和3.25%,PTX在载体中以非晶型状态存在。与Taxol注射液相比,阳离子型紫杉醇乳脂体具有明显的缓释作用,对MCF-7人乳腺癌细胞的IC50降低。结论:PTX-CTAB-NES正电性强,包封率高,缓慢释放药物,细胞毒性大,是瘤内原位给药的理想载体。     

抗艾滋病药物靶向递送系统的研究进展

抗艾滋病药物的发现及使用有效地延长了患者的生命,提高了患者的生活质量,但其治疗针对性不强,不能有效清除体内特定部位的HIV病毒。为此,人们采用多种技术手段,制备各种形式的抗艾滋病药物递送载体,如纳米粒、脂质体、树状大分子等,希望针对不同细胞和解剖学的病原体库进行靶向药物递送。本文对近年来有关抗艾滋病药物靶向制剂研究的进展做一综述。     

聚合物胶束作为药物载体及其在肿瘤靶向方面的研究进展

聚合物胶束具有粒径小、稳定性高、滞留时间长、良好的生物相容性等特点,这些优良性质使得聚合物胶束作为药物载体具有许多独特的优势。近年来,涌现了许多围绕聚合物胶束设计肿瘤靶向给药系统的报道,包括利用肿瘤的病理学性质,设计被动靶向给药系统和对聚合物胶束进行表面修饰,设计主动靶向给药系统。本文主要综述了聚合物胶束作为肿瘤靶向药物载体的研究进展。     

A novel progress of drug delivery system for organelle targeting in tumour cells

Abstract

At present, malignant tumours have become one of the most serious diseases that endanger human health. According to a survey on causes of death in Chinese population in early 1990s, the malignant tumours were the second leading cause of death. In the treatment of tumours, the ideal situation is that drugs should target and accumulate at tumour sites and destroy tumour cells specifically, without affecting normal cells and stem cells with regenerative capacity. This requires drugs to be specifically transported to the target organs, tissues, cells, and even specific organelles, like mitochondria, nuclei, lysosomes, endoplasmic reticulum (ER), and Golgi apparatus (GA). The nano drug delivery system can not only protect drugs from degradation but also facilitate functional modification and targeted drug delivery to the tumour site. This article mainly reviews the targeting of nano drug delivery systems to tumour cytoplasmic matrix, nucleus, mitochondria, ER, and lysosomes. Organelle-specific drug delivery system will be a major mean of targeting drug delivery with lower toxicity, less dosage and higher drug concentration in tumour cells.     

Development and characterization of nanolipobeads-based dual drug delivery system for H. Pylori targeting

Abstract

The objective of the present investigation was to prepare and evaluate nanolipobeads which permit the targeting of drugs to H. Pylori and potentially used for the treatment of gastric ulcer. For this polyvinyl alcohol nanoparticles were prepared by freeze thaw cyclizing method and surface acylation was done by treating with (1M) palmitoyl chloride in hexane followed by addition of 0.1 N NaOH to induce acylation by adjusting pH below 6.5. Finally, nanolipobeads synthesis was carried out by combining equal parts of suspension of acylated poly vinyl alcohol nanoparticles (PVA-NPs) and AMOX encapsulated PE liposomes suspension. The uniformity of supported PE lipid layer on acylated PVA-NPs was examined using fluorescence and confocal laser scanning electron microscopy. The optimized nanolipobeads formulation demonstrated 773.3?±?4.3?nm average age size and 84.7?±?2.9% of AMOX and 67.5?±?2.8% of RBC release up to 72?h, respectively. Furthermore, binding specificity and targeting propensity toward H. pylori (SKP-56) was confirmed by agglutination and in situ adherence assay. Reduction of the absolute alcohol induced ulcerogenic index from 3.01?±?0.25 to 0.31?±?0.09 and 100% H. pylori clearance rate was observed. These results suggested that nanolipobeads are potential vector for development of dual drug delivery for effective treatment of H. pylori associated peptic ulcer.     

Functional multilayered capsules for targeting and local drug delivery

One of the key challenges in the field of bio-nanotechnology for drug delivery systems (DDS) is the development of nano- or micro-sized delivery carriers possessing both targeting functionalities for specific tissues or cells, and controlled release properties for encapsulated drug molecules, proteins and genes. Hollow capsules developed by layer-by-layer (LbL) assembly have attracted much attention over the past few years owing to their ability to be modified, their capacity to encapsulate a wide range of chemicals, and the variety of functionalities with which they can be enhanced. Current research on LbL capsules focuses on the development of functionalized capsules for specific targeting of cancer or immune cells, and on controlling their release properties by environmental stimuli. This review discusses recent advances in DDS using functional hollow capsules specific for the cellular and tissue-targeted delivery, as well as stimuli-responsive controlled release. DDS based on functional hollow capsules may contribute to the development of new nano-medicines.     

An insight on hyaluronic acid in drug targeting and drug delivery

Hyaluronic acid (HA) has recently been studied for its use in drug delivery applications. Medically, HA is used as a surgical aid in ophthalmology. It also possesses therapeutic potential in the treatment of arthritis and wound healing. HA-binding receptors, CD44 and receptor for hyaluronan-mediated motility have attracted much enthusiasm, mainly because they are believed to be involved in cancer metastasis. This review unravels the role of HA in drug delivery and targeting. Designing of various novel drug delivery systems using HA as a biopolymer will also be reviewed in the present article.     

内质网靶向递药系统用于抗肿瘤免疫治疗的研究进展

内质网作为真核细胞内功能多样的细胞器,不仅是蛋白质合成与修饰的关键场所,也是胞内信号转导的重要位点,影响着细胞的功能发挥、存活及凋亡。内质网稳态的失衡会引起内质网应激,这与肿瘤的发生与发展密不可分。在一些药物(蒽醌类及奥沙利铂等)的作用下,过度的内质网应激则会介导肿瘤细胞的免疫原性细胞死亡并激发抗肿瘤免疫反应,在治疗后期形成长期免疫记忆。但是,这些药物往往存在靶向性差等问题,在肿瘤细胞内质网的蓄积量极低,限制了其临床疗效。因此,内质网靶向药物的研究将为更高效更精准的抗肿瘤免疫治疗提供参考。本文就内质网与肿瘤免疫的关系,以及近年来基于内质网靶向的抗肿瘤免疫治疗的策略进行综述,并对内质网靶向策略存在的问题及未来发展方向进行总结与展望。     

Magnetic targeting for site-specific drug delivery: applications and clinical potential

Background: Magnetic vehicles are very attractive for delivery of therapeutic agents as they can be targeted to specific locations in the body through the application of a magnetic field gradient. The magnetic localization of a therapeutic agent results in the concentration of the therapy at the target site consequently reducing or eliminating the systemic drug side effects. Objective: The aim of this review is to provide an update on the progress made in the development of the magnetic targeting technique addressing characteristics of the magnetic carriers and limitations of the current targeting magnet systems. Methods: This review discusses fundamental requirements for the optimal formulation of the magnetic carrier, current applications and potentially new approaches for the magnetically mediated, site-specific localization of therapeutic agents, including drugs, genes and cells. Results/conclusion: More efficient targeting magnetic systems in combination with prolonged circulation lifespan and carriers' surface recognition properties will improve the targeting efficiency of magnetic nanocarriers and enhance therapeutic agent availability at the molecular site of agent action. The main future magnetic targeting applications were categorized emphasizing the most promising directions and possible strategies for improving the magnetic targeting technique.     

Application of traditional Chinese medicine preparation in targeting drug delivery system

Abstract

Targeting drug system (TDS) or targeted drug delivery system (TDDS) is a new kind of drug delivery system which could make drug to be directly concentrated on the target site with high curative effects and low side-effects. As the quintessence of Chinese culture, traditional Chinese medicine (TCM) has a large advantage in many disease clinical treatments, especially in cancer, hypertension and many other intractable diseases owing to their low toxicity and side-effects relative to western medicine. This article reviews literatures on development of TCM-targeted preparations which were published in the past 10 years. TDS including active-targeting, passive-targeting and physical-chemical-targeting preparations were introduced through domestic and overseas literatures to reveal the unique advantages of TCM-targeting preparations in drug delivery system. In this article, we have reviewed some kinds of TCM-targeting preparations and indicated that great attention should be paid to the research on the TCM-targeting preparations.     

Monocytes: a novel drug delivery system targeting atherosclerosis

Abstract

Scavenging of reactive oxygen species (ROS) by antioxidants holds great promise to alleviate the symptoms of cardiovascular diseases and atherosclerosis. In atherosclerosis, damaged endothelial cells (EC) generate more ROS and inflammatory mediators, which recruit more monocytes to the EC. Antioxidants are good therapeutic drug candidates; however, antioxidant enzymes such as catalase are easily degraded by proteases in vivo and chemical mimetics of superoxide dismutase such as tempol and tempo require a target-specific delivery system since hydrophobic tempol or tempo can diffuse into any type of cells non-specifically. Here, we report a novel monocyte-based drug delivery system encapsulating either catalase or tempol/tempo. Monocyte as a novel drug delivery vehicle offers advantages over other delivery systems due to its target specificity to damaged EC. The delivery system can also be easily fabricated in biological conditions and keeps antioxidants active. Membrane impermeable catalase with protease inhibitors was formulated in monocytes via a hypotonic/resealing method and membrane permeable tempol/tempo were encapsulated in monocytes via passive diffusion with 40–60% encapsulation efficiency. Antioxidant-loaded monocytes targeted EC and the antioxidants scavenged more than 90% intracellular ROS generated by cytokines or exogenous ROS. We anticipate numerous applications of the monocyte-based drug delivery system, given its target specificity to activated EC.