液相预柱毛细管电泳技术在手性药物对映体与白蛋白相互作用研究中的应用

在对碱性药物吡啶茚胺、四氢萘唑啉、去甲肾素茶碱和维拉帕米(verapamil)等药物手性拆分的基础上,运用液相预柱毛细管电泳（LPC-CE）技术,建立了对药物对映体与人血清白蛋白（HSA）相互作用体系中对映体浓度的检测方法.　该技术利用HSA与药物在生理pH下的电泳特性差异,使HSA留在预柱内或反向流出,不进入手性拆分区域,从而消除白蛋白对药物对映体拆分及浓度检测的干扰.　对维拉帕米对映体与HSA结合参数以及多药物组分竞争结合的研究表明,该技术为多种药物与蛋白共存的复杂体系研究提供了一条有效的途径.     

万古霉素手性膜拆分D,L-苯甘氨酸及手性拆分机理

以万古霉素和1,6-己二异腈酸酯为单体,通过界面聚合法在聚砜基膜上制备了万古霉素手性高分子膜.利用红外光谱及扫描电子显微镜对该膜进行了表征.将其用于青霉素及头孢菌素类药物的重要中间体苯甘氨酸的手性拆分,通过优化单体摩尔比、界面聚合时间及外消旋体溶液浓度等分离参数,可达到超过70%的D-苯甘氨酸对映体过剩值的手性分离.通过比较研究手性膜吸附、固相萃取、膜色谱、膜渗析和膜超滤过程,发现手性膜上优先吸附的对映体L-苯甘氨酸并不是各种模式下优先透过的对映体,结合外消旋体的缔合特性,提出了"吸附-缔合-扩散"的手性膜分离机理.     

替考拉宁高效液相色谱手性固定相的制备研究

替考拉宁属于大环抗生素,具有半篮状结构和多个手性中心,是常见的手性识别材料,广泛应用于对映体的色谱手性分离分析.本文研究了以替考拉宁为手性识别剂,采用键合的方法制备得到9种高效液相色谱手性固定相,用于苯甘氨酸和对羟基苯甘氨酸的拆分研究,并且考察了重现性和稳定性及进样量对拆分结果的影响.实验结果表明,9种手性固定相均具有拆分苯甘氨酸及对羟基苯甘氨酸的能力.     

人血清白蛋白柱上药物的手性拆分

考察了４种酸性药物和１种中性药物对映体在人血清白蛋白手性固定相上的保留行为。这５种药物与人血清白蛋白结合的亲和力高，难于实现快速分离，作者提出在流动相中加入短链脂肪酸－正己酸，可快速手性拆分非诺洛芬、萘普生和布洛芬。酮基布洛芬对映体分离选择性随乙腈浓度升高而增大，流动相中加入适量异丙醇可使对映体选择性大大增加（α～１．２３），华法令同样可取得很好分离。     

用荧光猝灭和荧光加强两种理论研究喹诺酮类新药与白蛋白的作用

应用荧光加强和荧光猝灭两种理论公式, 对四种喹诺酮类药物与人血清和牛血清白蛋白的作用作进行了对比研究, 对药物与白蛋白的结合特点和通常的表征量(解离常数、 猝灭常数、 猝灭效率、 能量转移效率、 给体 受体作用距离等)进行了深入地分析; 在白蛋白与药物结合类型上, 四种药物对HSA和BSA的猝灭实验结果表明, 这种由给体-受体结合引起的猝灭作用类型不是由生物大分子血清白蛋白单方面决定的, 而是由血清白蛋白与药物、 即给体与受体两者的分子结构和相互匹配共同决定的.     

应用磁金纳米粒子研究牛血清白蛋白与牛蒡子苷之间的相互作用

建立了用于确定血清白蛋白与中药有效成分相互作用结合常数和结合位点数的新方法.利用磁金纳米粒子的超顺磁性和生物相容性,将其作为白蛋白的载体.将牛血清白蛋白固定在磁金纳米粒子上,白蛋白与药物结合后,通过外加磁场将磁金纳米粒子-白蛋白-药物复合物与游离药物分离,通过荧光光谱法得到的游离药物浓度,根据Scatchard方程直接计算出白蛋白与药物的结合常数和结合位点数.本方法用于研究牛血清白蛋白和牛蒡子苷之间的相互作用,结合常数为2.09×105 L/mol,结合位点数为16.63.通过外加磁场作用,使白蛋白从样品溶液中分离出来,样品溶液中只有药物,消除了测定药物时白蛋白的影响,因此所求得的结合位点的数目更准确.实验结果表明,本方法可用于测定分子间非共价结合的结合常数和结合位点数,同时为研究中药有效成分与血清白蛋白相互作用提供了参考.     

LC-MS(/MS)研究金属抗肿瘤化合物与血清白蛋白的相互作用

研究金属药物与血清白蛋白的相互作用,以及这种相互作用对药物在人体内的分布、代谢和排泄的影响,对深入理解金属类药物的分子作用机理具有重要的意义.本实验建立了一种高效、灵敏的Bottom-up蛋白质组学质谱分析方法,研究了金属抗肿瘤药物顺铂和两种自行开发的新型有机金属钌抗肿瘤化合物与血清白蛋白的相互作用,鉴定了金属化合物与血清白蛋白的结合位点.     

手性β-氨基醇的简捷合成及其不对称催化反应

从易得原料D-苯甘氨酸出发,经酯化、N-烷基化及还原等三步反应合成了五个手性β-氨基醇5和6.以此为手性配体,对催化芳香醛的不对称烯丙基化反应进行了初步研究,显示了中等程度的立体选择性.     

苯环型化合物定量二维手性程度的研究

基于权原子和, 提出了镶嵌在二维空间的苯环型化合物的手性程度, 其中权原子和为与原子间的距离有关的原子不对称环境描述. 在描述化合物的手性时, 并没有采用简单的标记-手性或非手性, 而是采用定量的方式来表征化合物的手性程度. 定量手性程度能够区分对映体, 并且一对对映体的手性程度为相反数. 手性程度不仅仅可以采用单值,还可以采用多维向量来表示. 此外, 还将手性程度推广到三维正烷烃的旋转构象异构体描述, 即首先将正烷烃的旋转异构体转化为苯环型化合物, 然后采用手性程度描述其三维构象.     

含芘手性探针分子与蛋白质作用机理的时间分辨荧光光谱研究

采用时间分辨荧光光谱等手段研究了手性探针分子L-[4-(1-芘基)]丁酰基苯丙氨酸(PLP)与溶菌酶(Lys)、牛血清白蛋白(BSA)和人血清白蛋白(HSA)的结合过程及机理,探讨了三氯六氨合钴(CoHA)对不同复合体系内芘基的荧光猝灭作用.结果表明,PLP在与血清白蛋白的结合过程中是以芘基插入到血清白蛋白疏水空腔中的方式与蛋白质结合的;而PLP与Lys的结合部位处在其表面的疏水部分.     

Fast enantiomeric separation of basis drugs by electrokinetic chromatography. Application to the quantitation of terbutaline in a pharmaceutical preparation

Electrokinetic chromatography (EKC) using micelles of bile salts alone or mixed with sodium dodecyl sulfate (SDS) and neutral, anionic, or cationic cyclodextrins (CDs) in the separation buffer has been employed in order to achieve fast enantiomeric separation of basic drugs. A study of the enantiomeric separation ability of these chiral selectors concerning four basic drugs (epinephrine, terbutaline, clenbuterol, and salbutamol) has been carried out under different experimental conditions. The best chiral selectors to perform the enantiomeric separation of these drugs were neutral beta-CD derivatives, specifically permethylated beta-CD PM-beta-CD. The effect of the PM-beta-CD concentration, temperature, and applied voltage on the enantiomeric resolution of the basic drugs was investigated. The use of a 25 mM ammonium acetate buffer (pH 5.0), 30 mM in PM-beta-CD together with an applied voltage of 20 kV and a temperature of 15 degrees C enabled the individual and fast enantiomeric separation of epinephrine, norepinephrine, terbutaline, clenbuterol, and salbutamol each one into its two enantiomers in less than 3 min. The EKC method was validated (precision and accuracy) to quantitate terbutaline in a pharmaceutical preparation, obtaining a limit of detection of 4 microg/mL.     

高效液相色谱法直接测定几种非甾体类解热镇痛药物中的对映体含量

用WHELK-O1手性色谱柱，在正相条件下测定了几种非甾体类解热镇痛药物萘普生、布洛芬、酮基布洛芬和苯氧布洛芬等中对映体的含量。结果表明：这种手性固定相色谱柱能够以正己烷和异丙醇为流动相，简便、快速、准确地测定非甾类药物中对映体的含量。     

Study on the enantiomeric ratio of the pharmaceutical substances alkannin and shikonin

The chiral pair alkannin and shikonin (A/S) are potent pharmaceutical substances with a wide spectrum of biological activity; their enantiomeric ratio does not influence the major biological activity studied hitherto. Nevertheless, in pharmaceutical development and approval of chiral drugs from the Health and Regulatory Authorities, full documentation of methods of analysis of enantiomeric drugs, is required in order to evaluate the enantiomeric purity of starting materials and final products and to control the stability of enantiomers in pharmaceutical formulations under several experimental conditions. In the present study, the enantiomeric ratio of A/S was determined in several commercial samples of alkannin and shikonin and also the proportion of A/S derivatives in several Alkanna root samples, which are all used as active ingredients in pharmaceuticals. Light and air proved not to influence the enantiomeric ratio of A/S on a shikonin commercial sample, and temperature also did not alter the A/S ratio on shikonin and alkannin commercial samples. Microencapsulation of alkannin and shikonin commercial samples in ethylcellulose microspheres and also molecular inclusion of a shikonin commercial sample in beta-hydroxypropyl-cyclodextrin, which are used as drug delivery systems, did not alter the A/S enantiomeric ratio.     

以L-白氨酸为手性选择剂用毛细管电泳法拆分12种手性药物

 建立了一种以L 白氨酸为手性选择剂用毛细管区带电泳法快速分离 12种手性药物的方法。实验结果表明 ,手性对映体的分离度受L 白氨酸浓度和缓冲液 pH的影响。在含有 70mmol/LL 白氨酸 ,5 0mmol/L硼砂 (pH9.0 )的溶液中 ,12种手性药物在 11min之内得到了基线分离。     

Cationic vesicles as chiral selector for enantioseparations of nonsteroidal antiinflammatory drugs by micellar electrokinetic chromatography

A vesicle-forming chiral cationic surfactant (1R,2S)-(-)-N-dodecyl-N-methyl-ephedrinium bromide was evaluated as a pseudo-stationary phase in micellar electrokinetic chromatography (MEKC) for enantioseparation of eight non-steroidal anti-inflammatory drugs e.g., carprofen, flurbiprofen, fenoprofen, ibuprofen, indoprofen, ketoprofen, naproxen and suprofen by capillary electrophoresis. The effects of varying experimental conditions such as pH and concentration of surfactant in the running buffer on the enantiomer separation of the drugs are reported. A mixture of five of the above drugs was separated and each enantiomeric pair was also separated simultaneously in a single run by use of the surfactant. The strong electrostatic interactions between the analytes and the vesicles seemed to have a major role in the enantiomeric separation of the profens.     

Study of the enantiomeric separation of the anticholinergic drugs on two immobilized polysaccharide‐based chiral stationary phases by HPLC and the possible chiral recognition mechanisms

In this work, the enantiomeric separation of ten anticholinergic drugs was first examined on two derivative polysaccharide chiral stationary phases (CSPs), i.e., Chiralpak ID and Chiralpak IA in the normal phase mode. Except for scopolamine hydrobromide, the remaining nine analytes could be completely separated with good resolutions using both columns under the optimized mobile phase conditions. And the enantiomeric discrimination ability of the studied CSPs towards nine analytes was in the order of Chiralpak ID > Chiralpak IA. The influences of organic modifier types, alcohol content, and base/acid additives on the enantiomeric separation were evaluated and optimized. According to the experimental results, the effect of the structures of analytes on enantiomeric separation was discussed. Additionally, the chiral recognition mechanisms were proposed based on the thermodynamic analysis of the experimental data.     

Chiral separation of basic drugs by capillary electrophoresis with carboxymethylcyclodextrins

Capillary electrophoresis (CE) with carboxymethylated beta- or gamma-cyclodextrins was used to achieve the rapid enantiomeric separation of a set of basic drugs. The enantiomers of 12 chiral amino-containing pharmaceutical compounds belonging to various therapeutic categories were analyzed by CE using an uncoated 60 cm x 75 microm I.D. silica capillary. Several experimental parameters such as the nature, concentration and pH of the buffer, nature and concentration of the anionic cyclodextrin and temperature were studied in order to optimize the enantiomeric separation. The variation of the solute partition coefficient for the chiral selector, the enantioselectivity and resolution factors are used to assess the quality of the chiral separation. It is shown that the solute affinity for the chiral selector is not related to its enantioresolution factor. None of the two cyclodextrin selectors used was able to separate the whole set of basic drugs.     

Enantiomeric fraction determination of chiral drugs in environmental samples using chiral liquid chromatography and mass spectrometry

When it was recognized that chiral drug residues have stereospecific toxicity towards environmental organisms the attention given to enantiomeric fraction determination of chiral drugs in the environment increased. Among various analytical techniques, chiral liquid chromatography (LC) coupled with mass spectrometry (MS) has been widely used due to its simplicity, wide applicability and high sensitivity. In this review, we aim to provide a comprehensive overview and comparison of the types of chiral stationary phases, elution modes and MS detection techniques employed and address the advances and limitations. The impact of the mobile phase composition on enantioseparation and MS detection are discussed based on the different methods developed. In addition, diverse applications for the enantiomeric fraction determination of chiral drugs in environmental matrices using chiral LC and MS are discussed in depth.     

Enantiomeric Resolution of a Chiral Sulfoxide Series by LC on Synthetic Polymeric Columns with Multimodal Elution

The liquid chromatography enantiomeric separation of a series of 17 chiral sulfoxides was systematically investigated using multimodal elution with the new synthetic polymeric stationary phases P-CAP, P-CAP DP and DEAVB. The sulfoxide series was composed of aryl alkyl sulfoxides, benzoimidazole sulfoxides and the drugs modafinil, albendazole sulfoxide, omeprazole, lansoprazole, pantoprazole and rabeprazole. This work examines the effectiveness of the polymeric chiral stationary phases for the separation of chiral sulfoxides and describes the superiority of DEABV for these separations in three different elution modes. The first ever reversed phase enantiomeric separations on these columns is demonstrated.