药物分子设计的策略：双靶标药物设计

新药研究可分两种模式：以生理学和表型为基础的研究和以生物靶标为核心的药物研究,这两种模式相互补充和印证。当今以靶标为切入点的模式占主导地位,研发出不少新药。许多疾病如肿瘤、代谢性和中枢神经系统疾病的药物治疗非单一靶标可治愈,同时干预与疾病相关的双（多）靶标药物可提高药物的效力,因而成为创制新药的活跃领域。双靶标药物可以是两个受体的调节剂、两个酶的抑制剂或同时作用于酶和受体或作用于受体和通道或转运蛋白的双功能性分子等。从药物分子设计的视角,构建双靶标药物分子可将两个活性分子或其药效团用连接基连接在一起,构成连接型分子;两个活性分子的部分结构或药效团特征相同,可将共同部分融合或并合,形成融合型或并合型分子,可以控制分子的大小和相对分子质量,使得分子结构的药效空间与药代动力学空间有较大的重叠,提高成药的几率。     

Structure based drug design for HIV protease: from molecular modeling to cheminformatics

Significant progress over the past decade in virtual representations of molecules and their physicochemical properties has produced new drugs from virtual screening of the structures of single protein molecules by conventional modeling methods. The development of clinical antiviral drugs from structural data for HIV protease has been a major success in structure based drug design. Techniques for virtual screening involve the ranking of the affinity of potential ligands for the target site on a protein. Two main alternatives have been developed: modeling of the target protein with a series of related ligand molecules, and docking molecules from a database to the target protein site. The computational speed and prediction accuracy will depend on the representation of the molecular structure and chemistry, the search or simulation algorithm, and the scoring function to rank the ligands. Moreover, the general challenges in modern computational drug design arise from the profusion of data, including whole genomes of DNA, protein structures, chemical libraries, affinity and pharmacological data. Therefore, software tools are being developed to manage and integrate diverse data, and extract and visualize meaningful relationships. Current areas of research include the development of searchable chemical databases, which requires new algorithms to represent molecules and search for structurally or chemically similar molecules, and the incorporation of machine learning techniques for data mining to improve the accuracy of predictions. Examples will be presented for the virtual screening of drugs that target HIV protease.     

Amikacin-loaded vascular prosthesis as an effective drug carrier

Strong covalent immobilization of amikacin on Uni-Graft((R)) DV straight vascular prostheses made of gelatine-sealed poly(ethylene terephthalate) fibres was performed according to procedure described in the Polish Patent No. P-358934. The concentrations of amikacin in sample solutions were estimated either by HPLC or by UV spectroscopy method previously optimized for amikacin measurements. A high correlation was found between these two methods. It was found that the antibiotic was bound in mixed-type way via three types of interactions: strong covalent bonds (dominating amount: 81.84%) and weak interactions: physical adsorption and ionic bonds (18.19%). Even when total amount of physically and ionically attached drug has been released, the remaining covalently bound amount still locally protected the prostheses in vitro against bacteria. The release test was conducted in PBS at pH 7.4 at 37 degrees C and showed that about 15% of total drug amount was eluted from the matrix during the first 7 days of shaking, then no more antibiotic was released. It suggested that about 85% of amikacin attached to prosthesis modified in mixed-type mode was bound via covalent interactions. A bacterial inhibition test on Escherichia coli ATCC 25922, Staphylococcus aureus ATCC 25923 and Pseudomonas aeruginosa ATCC 27853 showed inhibition of growth for all strains at low inoculum concentrations up to 30 days as well as high inoculum concentration for E. coli. At high concentrations of S. aureus and P. aeruginosa, the modified prostheses showed slight bacteriostatic effect since 10th day of experiment. Amikacin-modified vascular prostheses might therefore be protected against bacterial infection locally, without long-lasting drug release to human system.     

Paclitaxel delivery using carrier made from curcumin derivative: Synergism between carrier and the loaded drug for effective cancer treatment

To fully make use of the synergism between paclitaxel and curcumin (CUR) in cancer treatment, carrier made from CUR derivative was synthesized and used to deliver paclitaxel into cancer cells. The methoxylpolyethylene oxide‐linked palmitate‐modified curcumin (mPEO–CUR–PA) was synthesized and the obtained amphiphilic mPEO–CUR–PA molecules were allowed to self‐assemble into microspheres. In vitro release of free CUR from mPEO–CUR–PA in the presence of lipase was proofed and the ability of cells to endocytose mPEO–CUR–PA microspheres was verified. Cytotoxic activity of the mPEO–CUR–PA microspheres toward cancer cell lines (S102 and A549) was evaluated and compared with that of the unmodified CUR. Paclitaxel was then loaded into the microspheres and the paclitaxel‐loaded mPEO–CUR–PA microspheres showed up to fivefold to 44‐fold increased in vitro cytotoxicity (in terms of % cell mortality) in susceptible (HCC‐S102 and A549) and paclitaxel‐resistant (A549RT‐eto) cancer cells, respectively, compared with that of free paclitaxel.     

A novel strategy to achieve effective drug delivery: exploit cells as carrier combined with nanoparticles

Cell-mediated drug delivery systems employ specific cells as drug vehicles to deliver drugs to targeted sites. Therapeutics or imaging agents are loaded into these cells and then released in diseased sites. These specific cells mainly include red blood cells, leukocytes, stem cells and so on. The cell acts as a Trojan horse to transfer the drug from circulating blood to the diseased tissue. In such a system, these cells keep their original properties, which allow them to mimic the migration behavior of specific cells to carry drug to the targeted site after in vivo administration. This strategy elegantly combines the advantages of both carriers, i.e. the adjustability of nanoparticles (NPs) and the natural functions of active cells, which therefore provides a new perspective to challenge current obstacles in drug delivery. This review will describe a fundamental understanding of these cell-based drug delivery systems, and discuss the great potential of combinational application of cell carrier and NPs.     

Combating mutations in genetic disease and drug resistance: understanding molecular mechanisms to guide drug design

Introduction: Mutations introduce diversity into genomes, leading to selective changes and driving evolution. These changes have contributed to the emergence of many of the current major health concerns of the 21st century, from the development of genetic diseases and cancers to the rise and spread of drug resistance. The experimental systematic testing of all mutations in a system of interest is impractical and not cost-effective, which has created interest in the development of computational tools to understand the molecular consequences of mutations to aid and guide rational experimentation.

Areas covered: Here, the authors discuss the recent development of computational methods to understand the effects of coding mutations to protein function and interactions, particularly in the context of the 3D structure of the protein.

Expert opinion: While significant progress has been made in terms of innovative tools to understand and quantify the different range of effects in which a mutation or a set of mutations can give rise to a phenotype, a great gap still exists when integrating these predictions and drawing causality conclusions linking variants. This often requires a detailed understanding of the system being perturbed. However, as part of the drug development process it can be used preemptively in a similar fashion to pharmacokinetics predictions, to guide development of therapeutics to help guide the design and analysis of clinical trials, patient treatment and public health policy strategies.     

药物分子设计的策略：苗头和先导物的品质决定新药的成败

苗头化合物-先导物-候选药物是创制新药的三个重要里程碑，其中候选药物的确定是新药创制的关键环节，将创制过程分成研究和开发两个阶段，并且开发阶段所有环节都取决于候选药物的化学结构，所以决定了临床前和临床研究的命运。候选药物质量的高低又受制于先导化合物的类药性和苗头化合物的品质，苗头化合物演化成先导物是将新药的研究植根于有研发前景的结构上，先导物的优化是将活性化合物转化成候选药物的过程，是在药效、药代、安全性和物化性质等多维空间中的优化操作。本文结合实例讨论了发现苗头、确定先导物、先导物优化和确定候选药物的策略原则。     

Fluorine local environment: from screening to drug design

Fluorine is widely used in the lead optimization phase of drug discovery projects. More recently, fluorine NMR-based spectroscopy has emerged as a versatile, reliable and efficient tool for performing binding and biochemical assays. Different libraries of fluorinated compounds, designed by maximizing the chemical space around the fluorine atom, are screened for identifying binding fragments and for detecting putative fluorophilic hot spots on the desired macromolecular target. A statistical analysis of the fluorine NMR chemical shift, which is a marker of the fluorine local environment, and of the X-ray structures of fluorinated molecules has resulted in the development of the 'rule of shielding'. This method could become a useful tool for lead optimization and for designing novel chemical scaffolds that recognize distinct protein structural motifs.     

药物分子设计的策略:药理活性与成药性

化合物的内在活性和成药性是创新药物的两个基本要素,活性是药物的基础和核心,成药性是辅佐活性发挥药效的必要条件,两者互为依存。药物在体内的药剂相、药代动力相和药效相可概括为活性和成药性的展示过程。成药性是药物除活性外的其他所有性质,包括物理化学性质、生物化学性质、药代动力学性质和毒副作用,这是在不同层次上表征药物的性质和行为,但又相互关联与制约。活性与成药性由化学结构所决定,体现在微观结构与宏观性质的结合上,寓于分子的结构之中。先导物的优化是对活性、物化、生化、药代和安全性等性质的多维空间的分子操作,因而具有丰富的药物化学内涵。     

Understanding of molecular pathogenesis of Alzheimer's disease: implications for drug development

Recent advances in the knowledge about Alzheimer pathogenesis indicate several tactics for the development of drugs to treat Alzheimer's disease. Firstly, the function of presenilin, the causative gene for most familial Alzheimer's disease, has been demonstrated to be the protease in the Notch signaling system. Presenilin cleaves the transmembrane domain of the C-terminal fragment of the Notch-1 molecule, which is generated by proteolysis by furin-like proteases. APP is also cleaved by presenilin at the gamma cut site, implying that presenilin is gamma-secretase itself or at least closely functioning with gamma-secretase. A recent paper has demonstrated that immunization of APP transgenic mouse with amyloid beta 42 may decrease and prevent amyloid deposition in brain tissue. This unique and novel approach may open the new tactics for developing anti-dementia drugs. Another important finding comes from the identification of the function of prolyl isomerase. It is demonstrated that pin 1, intra-nuclear prolyl isomerase, can restore the microtubule binding capacity of phosphorylated tau, which clearly shows a solid strategy for developing drugs for preventing neuronal degeneration.     

药物分子设计的策略：论药效团和骨架迁越

药物分子是由药效团和结构骨架构成的，药效团是由不连续的离散的原子、基团或片断所构成，但需结合在分子骨架上，形成具体的分子。骨架具有连续性，相同的药效团附着在不同的分子骨架上，构成了作用于同一靶标而结构多样的化合物。骨架依据受体的柔性和可塑性形成了“杂乱性”的空间。显示了受体结合部位的杂乱性。杂乱性越大，可容纳的配体分子的结构多样性就越多，意味着结构修饰与变换的余地大，成药的机会多。由苗头化合物演化成先导物，进而优化成候选药物，这由化合物变革成安全、有效、稳定、可控的药物过程就是保持药效团、变换分子骨架、修饰基团和边链的过程。结构骨架的变化可分为3个层次：以电子等排原理变换骨架结构；以优势结构为导向变换骨架结构；以结构一活性演化的方式变换骨架结构，即骨架迁越。骨架迁越的目的是改善分子的物化、药代、稳定性和赋予分子的结构新颖性。该文以实例阐述了骨架变换的方法与技巧。     

What to expect from rational drug design

For more than 20 years, rational methods of drug design have belonged to the methodological core of drug development. Rational drug design based on structural knowledge of protein targets and on computational modelling of drug–target interaction holds out the promise of a predictable development process for highly innovative drugs. Still, it remains a challenge to make the available structural information fruitful for lead design. As a consequence, rational design is becoming increasingly interwoven with high-throughput screening. In addition, the relationship to the emerging systems-oriented approaches has yet to be specified.     

药物分子设计的模拟原理

药物分子设计的模拟原理郭宗儒（中国医学科学院、中国协和医科大学药物研究所，北京１０００５０）药物分子设计是人工预建可与机体重要功能成分（蛋白质、核酸、酶、受体、离子通道等）发生作用的化学物质的分子操作，以达到防治疾病、纠正失调的机体内环境的目的。药物...     

载药微球设计中常用的天然多糖材料的研究进展

天然多糖具有独特的结构和多种生物活性以及良好的生物相容性和可降解性,故其作为药物控制释放材料具有比合成聚合物更多的优势。现对目前常用的天然多糖如:海藻酸钠、壳聚糖、琼脂糖、卡拉胶、透明质酸的结构性能以及它们在微球设计中的制备与应用研究进展做一概述,以期能对开发新的天然多糖作为微球载体材料提供参考。     

定量构动关系与药物分子设计

阐述了定量构动关系的研究对于药物设计的重要性和必要性,介绍了表征药物分子的结构参数以及将药物结构参数与药动学参数进行关联的人工神经网络,综述了近年来国内外药物定量构动关系的研究进展。