液相色谱-核磁共振联用技术在药物分析中的应用

液相色谱(LC)是分离复杂混合物的较好方法,核磁共振(NMR)是结构分析的强有力工具.液相色谱-核磁共振(LC-NMR)联用技术是快速分离、确定结构的一种分析手段,具有广阔的应用前景.主要综述了LC-NMR联用技术在化学药物分析(包括未知杂质的结构分析、混合物中已知成分的定量分析)、中药及天然药物分析(包括异构体分析、新化合物的结构鉴定)、海洋生物及生化大分子、代谢产物分析中的应用.     

LC-NMR-MS联用技术及其在代谢物结构研究中的应用

本文综述了液相色谱-核磁共振-质谱(LC-NMR-MS)联用技术的最新发展,讨论了该技术在应用中面临的主要问题和解决方法,评述了 LC-NMR-MS 的联机方式和工作模式,并介绍了 LC-NMR-MS 技术在药物代谢物结构方面应用现状,最后展望了其今后的发展方向。     

溶液状态下利可君及其有关物质的结构研究

目的研究利可君的4个非对映异构体及其有关物质的结构。方法利用液相色谱-二极管阵列检测、液相色谱-串联质谱和液相色谱-核磁共振等联用技术研究利可君及有关物质的结构。采用Phenomnex Luna C₁₈色谱柱(250 mm×4.60 mm ID，5 μm)，水-乙腈-冰醋酸(58∶42∶0.3)为流动相。结果确定了在溶液状态下利可君及其有关物质的结构，发现其均有4个非对映异构体；还对利可君的4个非对映异构体在溶液中互变与稳定性进行比较与量子化学计算，证明其稳定构型为3r4s5r。结论利可君在溶液中非对映异构体相互转化，有一种优势构型。     

色谱联用技术在中药研究领域的应用

中药现代化离不开现代、高效的分离、分析技术。现代分析技术的发展，尤其是色谱联用技术的出现加快了中药研发的步伐。该技术具有所需样品量少、速度快等特点，且可得到更多信息。目前，正处于快速发展阶段并广泛应用的色谱联用技术包括气相色谱-质谱联用（GC—MS）、液相色谱质谱联用（LC—MS）、高效液相-核磁共振仪联用（HPLCNMR）、毛细管电泳-核磁共振仪联用（CE—NMR）、液相色谱-质谱／质谱联用（LC一／MS／MS）、液相色谱-核磁-质谱联用（LC—NMR—MS）、毛细管电泳-质谱联用（CEMS）等，本就其在中药研究领域的应用作一简要综述。     

高效液相色谱-质谱联用技术分析甘草及其提取物中黄酮类成分

本文运用高效液相色谱-质谱联用技术分析不同产地的甘草药材及其提取物中黄酮类成分.研究表明不同产地的甘草生药中黄酮类成分的种类和含量有着明显的差别,其高效液相色谱的指纹图谱存在显著差异.     

祛痘类化妆品中违禁添加克林霉素的HPLC-DAD和LC-MS法检测

采用高效液相色谱-二极管阵列检测器和液相色谱-质谱联用仪检测祛痘类化妆品中违禁添加的克林霉素.克林霉素在0.01～2 mg/ml浓度范围内线性良好,平均加样回收率为96.2％、98.5％和99.1％,RSD分别为3.0％、2.1％和1.3％.最低检出浓度为40 μg/g.     

降香药材色谱指纹图谱的建立及其在药材鉴定中的应用

目的建立评价降香药材质量的液相色谱指纹图谱分析方法，并采用液相色谱-质谱联用技术对其主要成分进行定性分析。方法采用Phenomenex Luna C₁₈色谱柱，以乙腈-0.3%醋酸水溶液为流动相梯度洗脱，流速为1.0 mL·min^-1，检测波长为275 nm，测定了37批不同来源的降香药材的HPLC-UV指纹图谱以及其中3批代表性药材的HPLC-DAD-MS图谱。结果根据指纹图谱相似度分析结果，将降香药材分为3类；利用HPLC-DAD-MS技术分析了3类药材化学组成上的异同，并分别在3类药材中指认了10个，7个和2个酚性成分。结论本方法可用于降香药材的指纹图谱测定，并为其质量评价提供可靠依据。     

核磁共振-质谱联用技术在药学领域的应用进展

目的：介绍液相色谱-核磁共振-质谱（LC-NMR-MS）联用技术的基本原理及其在药学领域的应用进展。方法：查阅国内外文献和相关资料，选取有代表性的文献进行综述。结果：阐述了LC-NMR-MS的仪器构造、工作模式、技术重点，及其在生物体内代谢物和天然产物结构鉴定方面的典型应用。结论：LC-NMR-MS作为一项新的分析手段，逐渐成为药学领域中化合物结构鉴定的强有力武器，得到越来越广泛的应用，具有巨大的发展前景。     

寡核苷酸药物及生物标志物的生物分析研究进展

寡核苷酸已成为多种疾病诊断和治疗的候选药物。寡核苷酸药物及其代谢物、生物标志物的定性定量分析是药物开发和评估所必需的,良好的分析方法有利于控制药品质量及准确定量药品浓度。本文主要探讨了逆转录-实时荧光定量PCR (RT-qPCR)、液相色谱-荧光(LC-FL)、液相色谱-质谱联用（LC-MS/MS）、液相色谱-高分辨质谱联用（LC-HRMS）在寡核苷酸药物和生物标志物的应用及各自的优缺点,旨在概述目前现有寡核苷酸药物和生物标志物的生物分析方法,以期为从事寡核苷酸诊断和治疗药物的研发、分析人员及企业提供参考,以期提高此类新药或仿制药一致性评价分析的水平。     

液相色谱-质谱联用技术在药物分析中的应用

液相色谱-质谱（LC—MS）联用技术体现了色谱和质谱优势的互补,将色谱的高分离性能和质谱的鉴别力强的特点相结合,组成了较完美的现代分析技术。本文介绍近年来液-质联用技术在药物分析研究领域的应用,随着液相色谱一质谱质联用技术的不断完善、发展,必将在药物分析中占据越来越重要的地位。     

HPLC-ELSD法测定参芪降糖颗粒中黄芪甲苷的含量

目的建立HPLC-ELSD法测定参芪降糖颗粒中黄芪甲苷的含量.方法采用大连依利特Hypersil C18(4.6×250mm,5μm)色谱柱;流动相:甲醇-水(75∶25),流速:1mL·min-1;柱温:40℃;检测器:Alltech ELSD 2000.结果黄芪甲苷在0.384～3.84μg范围内具有良好的线性关系,回收率为98.88%(RSD=1.52%,n=6).结论本法具有良好的精密度和重现性,结果准确可靠,可作为本产品的质量控制方法.     

HPLC-ELSD法同时测定熟地黄中果糖、葡萄糖含量

目的建立高效液相色谱-蒸发光散射检测法同时测定熟地黄饮片中葡萄糖、果糖的含量。方法色谱柱:ZorbaxRX-SIL(4.6×200mm);流动相:乙腈-水(95∶5);流速:1.0mL.min-1;柱温:25℃;ELSD:漂移管温度105℃,载气流速2.5mL.min-1。结果果糖在1.00～11.00μg范围内(r=0.99996),葡萄糖在0.95～10.45μg范围内(r=0.99991)线性良好,平均回收率分别为97.93%、98.65%,RSD分别为2.07%、2.48%(n=5)。结论该方法操作简便,可用来控制熟地黄饮片的质量。     

Structural studies of two antiaggregant RGDW peptides by lH and 13C NMR

The structural features of Arg-Gly-Asp-related sequences have been investigated by ¹H and ¹³C NMR. Two linear peptides which inhibit platelet aggregation with a high efficiency have been studied: D-Arg-Gly-Asp-Trp and L-Arg-Gly-Asp-Trp. Analysis of pH titration effects, amide proton exchange rates and inter-proton distances obtained from ROESY spectra suggest that these small fragments predominantly adopt a type II′β-turn structure in solution. Folding features of a non-active cyclic peptide based on the same sequence (cyclo-[Arg-Gly-Asp-Trp]₂) have also been investigated. The biological relevance of these structures is discussed.     

4-羟基香豆精类化合物抑菌作用及核磁共振光谱的研究

本文对二十几种4-羟基香豆精类化合物的抑菌作用进行了研究。发现它们在不同程度上对金黄色葡萄球菌和大肠杆菌有抑制作用。探讨了由于取代基不同对抑菌作用的影响。并对这类化合物的核磁共振光谱进行了研究,为今后这类化合物的结构鉴定提供了参考。     

糖类结构的核磁共振波谱及质谱分析

糖类结构分析是近年来生命科学研究的热点之一。由于糖类结构的复杂性，核磁共振波谱和质谱已成为其有力的分析手段。本文就核磁共振波谱和质谱两种分析手段用于糖类结构、构型和构象研究的最新进展作一综述。     

核磁共振法测定硫酸依替米星含量

通过核磁共振法对硫酸依替米星进行定性和定量分析.利用一维及二维核磁共振谱(DEPT、COSY、HSQC、HMBC),对<'1>H-NMR谱和<'13>C-NMR谱信号进行完整归属.在此基础上,采用氢核磁共振定量法,以对苯二酚为内标,测得硫酸依替米星中依替米星的含量为59.19%,RSD为0.24%,方法准确可靠,简便快速.     

Conformations of cyclic pentapeptide endothelin receptor antagonists

The solution conformations in methanol and chloroform of the endothelin A receptor antagonists cyclo(dV-L-dW-dD-P), 1, and cyclo(dV-^Nα-MeL-dW-dD-P), 2, have been studied by NMR spectroscopy at room temperature and below. In these solvents, both peptides were found to have a well defined peptide backbone conformation composed of a type II β turn at the Leu-D-Trp and a γ′ turn at Pro. This conformation is in agreement with results reported for 1 in other solvents and consistent with the expected location of the N-methyl substituent in that backbone. In methanol, both peptides show NOE and chemical shift evidence of close contact between the Leu and D-Trp side chains. This interaction is greatly reduced or absent in chloroform, and is stronger in methanol at 203 K than at 298 K.     

Computer-Aided Drug Discovery Approach Finds Calcium Sensitizer of Cardiac Troponin

In the fight against heart failure, therapeutics that have the ability to increase the contractile power of the heart are urgently needed. One possible route of action to improve heart contractile power is increasing the calcium sensitivity of the thin filament. From a pharmaceutical standpoint, calcium sensitizers have the distinct advantage of not altering cardiomyocyte calcium levels and thus have lower potential for side-effects. Small chemical molecules have been shown to bind to the interface between cTnC and the cTnI switch peptide and exhibit calcium-sensitizing properties, possibly by stabilizing cTnC in an open conformation. Building on existing structural data of a known calcium sensitizer bound to cardiac troponin, we combined computational structure-based virtual screening drug discovery methods and solution NMR titration assays to identify a novel calcium sensitizer 4-(4-(2,5-dimethylphenyl)-1-piperazinyl)-3-pyridinamine (NSC147866) which binds to cTnC and the cTnC-cTnI_147–163 complex. Its presence increases the affinity of switch peptide to cTnC by approximately a factor of two. This action is comparable to that of known levosimendan analogues.     

Hedgehog antagonist cyclopamine isomerizes to less potent forms when acidified

The effect of acid treatment of cyclopamine, a natural antagonist of the hedgehog (Hh) signaling pathway and a potential anti-cancer drug, has been studied. Previous reports have shown that under acidic conditions, as in the stomach, cyclopamine is less effective. Also, it has been stated that cyclopamine converts to veratramine, which has side effects such as hemolysis. In this study, we examined in detail the influence of acidification on structure and activity of cyclopamine. We found that of acidified cyclopamine converts to two previously unreported isomers, which we have called cyclopamine (S) and cyclopamine (X). These have likely gone undetected because cyclopamine is often analyzed with fast and hence lower resolving chromatographic methods. Compared to natural cyclopamine, these cyclopamine isomers have a significantly reduced effect on the ciliary transport of the Hh receptor smoothened, and reduced inhibition on the Hedgehog signaling pathway. The side effects of these isomers are unknown. Our findings can partly explain a reduced efficiency of cyclopamine in a gastric environment, and may help with the rational design of more pH independent cyclopamine analogues.     

Determination of isotope abundance for deuterium-labeled compounds by quantitative 1H NMR + 2H NMR

Deuterated reagents have been used in many research fields. Isotope abundance, as the feature parameter of deuterated reagents, the precise quantification, is of great importance. Based on quantitative nuclear magnetic resonance technology, a novel method that combines ¹H NMR + ²H NMR was systematically established to determine the isotopic abundance of deuterated reagents. The results showed that the isotopic abundance of partially labeled and fully labeled compounds calculated by this new method was even more accurate than that calculated by classical ¹H NMR and mass spectrometry (MS) methods. In brief, this new method is a robust strategy for the determination of isotope abundance in large-scale deuterated reagents.