LC-MS/MS法测定人血浆中布康唑浓度的不确定度评定

目的：评定LC-MS/MS法测定人血浆中布康唑浓度的不确定度。方法：分析测定过程中不确定度的来源，包括对照品的称量、仪器误差、标准溶液的配制、含药血浆样品的配制、血浆样品的处理、标准曲线的拟合、基质效应、重复性等，评定各来源分量的不确定度，计算合成不确定度和扩展不确定度。结果：人血浆中低（60.0 pg·mL^-1）、中（600.0 pg·mL^-1）、高（6 400.0 pg·mL^-1）浓度布康唑的扩展不确定度分别为5.62，63.90，626.26 pg·mL^-1（k=2，P=95%）。结论：LC-MS/MS法测定人血浆中布康唑浓度的不确定度主要由基质效应、血浆样品的处理（提取回收率），仪器误差、重复性（精密度）引入。     

UPLC-MS/MS测定73例患者血中头孢哌酮与舒巴坦的浓度

目的：建立液相色谱-串联质谱法（UPLC-MS/MS）同时测定人血浆中头孢哌酮与舒巴坦的浓度，分析头孢哌酮/舒巴坦血药浓度监测结果，为临床合理用药提供参考。方法：以氯唑沙宗为内标，采用Waters BEHC₁₈柱（2.1 mm×100 mm，1.7 μm）进行分离，通过串联质谱仪，负离子检测模式下，以多反应监测（MRM）方式进行定量测定。对某院2018年以不同给药方案进行治疗的73例住院患者测定的头孢哌酮/舒巴坦血药浓度结果进行分析。结果：头孢哌酮与舒巴坦在测定条件下1~200 mg·L^-1范围内线性关系良好，两者日内精密度RSD均<10%，基质效应分别为（72.77±0.99）%与（75.72±0.11）%，提取回收率均>90%。73例患者共监测血药浓度96次，其中不同给药方案2 g，q8 h（43例次）；2 g，q12 h（26例次）；2 g，q6 h（27例次），各组头孢哌酮血药浓度的中位数分别为34.12 mg·L^-1（4.12~177.79 mg·L^-1）、31.23 mg·L^-1（1.89~251.8 mg·L^-1）、59.96 mg·L^-1（1.77~140.58 mg·L^-1），舒巴坦血药浓度的中位数分别为6.3 mg·L^-1（0.61~136.01 mg·L^-1）、28.83 mg·L^-1（0.5~133.69 mg·L^-1）、11.17 mg·L^-1（0.73~143.53 mg·L^-1）。Mann-Whitney U检验显示，头孢哌酮血药浓度结果无统计学差异（P>0.05），舒巴坦有统计学差异（P<0.05）。结论：本检测方法操作简便、快速、重复性好，可满足临床头孢哌酮与舒巴坦浓度的检测；头孢哌酮/舒巴坦在不同给药方案下血药浓度结果与个体差异相关，有必要开展血药浓度监测并依据结果适时调整用药方案，提高治疗效果减少耐药率的发生。     

Investigation of non-linear Mate1-mediated efflux of trimethoprim in the mouse kidney as the mechanism underlying drug-drug interactions between trimethoprim and organic cations in the kidney

The purpose of this study was to elucidate the involvement of Mate1 in the tubular secretion of trimethoprim and saturation of Mate1-mediated efflux to address the mechanisms underlying the pharmacokinetic drug interactions with trimethoprim. Trimethoprim is a more potent inhibitor of MATE2-K than MATE1 with K_i values (μM) of 0.030–0.28 and 2.4–5.9, respectively. Trimethoprim is a substrate of human MATE1 and MATE2-K with K_m values of 2.3 ± 0.9 and 0.018 ± 0.004 μM, and mouse Mate1, but not human OCT2, mouse Oct1 and Oct2. Pyrimethamine significantly reduced the renal clearance (CL_R) of trimethoprim (mL/min/kg) from 40.0 ± 5.1 to 20.1 ± 3.7 (p < 0.05). Trimethoprim was given to mice at three infusion rates (150, 500, and 1500 nmol/min/kg). Together with an increase in the plasma concentrations of trimethoprim, the CL_R (mL/min/kg) of trimethoprim decreased to 25.9 ± 3.2, 13.5 ± 5.7, and 8.92 ± 1.50 at the respective rates. Trimethoprim decreased the CL_R of rhodamine 123 in an infusion rate-dependent manner: 11.5 ± 1.3 (control), 5.17 ± 1.55, 1.31 ± 0.50, and 0.532 ± 0.180. These results suggest that Mate1 mediates the tubular secretion of trimethoprim, and at therapeutic doses, MATEs-mediated efflux can be saturated, and thereby, cause drug interactions with other MATE substrates.     

四种大宗常用中药饮片中黄曲霉毒素污染状况分布比较研究

目的 测定不同来源的4种大宗常用中药饮片中黄曲霉毒素（AFB₁、AFB₂、AFG₁和AFG₂）的含量，比较不同基质中药饮片中黄曲霉毒素的分布状况。方法 基于免疫亲和柱净化-高效液相色谱分离-荧光检测器（IAC-HPLC-FLD）方法，分析不同产地共75批中药样品。结果 柏子仁、薏苡仁、决明子及党参共计75批中药饮片中，阳性检出：26批柏子仁（AFs 1.22-46.67 μg·kg^-1，AFB₁ 1.22-31.40 μg·kg^-1）、4批薏苡仁（AFs 1.97-41.13 μg·kg^-1，AFB₁ 1.97-36.40 μg·kg^-1）、1批决明子（AFs 13.65 μg·kg^-1，AFB₁ 12.60 μg·kg^-1），阳性率41%，超标率15%。阳性样品经 LC-MS/MS确证，排除假阳性。4种大宗常用中药饮片柏子仁、薏苡仁、决明子、党参中黄曲霉毒素的污染水平依次降低，阳性检出率分别为77%、29%、7%、0%，表明中药材中黄曲霉毒素的污染状况与药材基质密切相关。结论 针对易污染AFs的中药品种，需进一步加强其污染状况的全面检测分析，为黄曲霉毒素的有效防控以及完善中药的质量标准提供科学依据，从而保障中药用药安全。     

Carboxylesterase catalyzed 18O-labeling of carboxylic acid and its potential application in LC-MS/MS based quantification of drug metabolites

LC-MS quantification of drug metabolites is sometimes impeded by the availability of internal standards that often requires customized synthesis and/or extensive purification. Although isotopically labeled internal standards are considered ideal for LC-MS/MS based quantification, de novo synthesis using costly isotope-enriched starting materials makes it impractical for early stage of drug discovery. Therefore, quick access to these isotope-enriched compounds without chemical derivatization and purification will greatly facilitate LC-MS/MS based quantification. Herein, we report a novel ¹⁸O-labeling technique using metabolizing enzyme carboxylesterase (CES) and its potential application in metabolites quantification study. Substrates of CES typically undergo a two-step oxygen exchange with H₂¹⁸O in the presence of the enzyme, generating singly- and doubly-¹⁸O-labeled carboxylic acids; however, unexpected hydrolytic behavior was observed for three of the test compounds – indomethacin, piperacillin and clopidogrel. These unusual observations led to the discovery of several novel hydrolytic mechanisms. Finally, when used as internal standard for LC-MS/MS based quantification, these in situ labeled compounds generated accurate quantitation comparable to the conventional standard curve method. The preliminary results suggest that this method has potential to eliminate laborious chemical synthesis of isotope-labeled internal standards for carboxylic acid-containing compounds, and can be developed to facilitate quantitative analysis in early-stage drug discovery.     

高效液相色谱串联质谱法测定氯沙坦钾中的遗传毒性杂质N-亚硝基-N-甲基-4-氨基丁酸

目的建立了一种高效液相色谱-三重四极杆串联质谱法,对氯沙坦钾原料药中遗传毒性杂质N-亚硝基-N-甲基-4-氨基丁酸(NMBA)进行测定。方法色谱柱为岛津Shim-pack XR-ODSⅡ色谱柱(2.0 mm×150 mm,2.2μm),流动相为0.1%甲酸水溶液(A)和甲醇(B),进行梯度洗脱,流速0.3 mL·min^-1,柱温为40℃,采用ESI离子化-三重四极杆质谱多反应监测(MRM)正离子模式检测,碰撞电压分别为-11,-13和-13 V,碰撞气氩气270 kPa,NMBA的离子对分别为m/z 147.15→117.10,147.15→87.10和147.15→44.10。结果该方法中NMBA在1~100 ng·mL^-1内线性关系良好,日内和日间的保留时间和峰面积的重复性良好(RSD均小于1.10%,n=6和n=18),低、中、高3个浓度的平均回收率在94.40%~98.04%之间。结论本方法简单方便,可快速有效的对氯沙坦钾原料药中NMBA进行限度检查并实现定量分析。     

Determination of polycyclic aromatic hydrocarbons (PAHs) in cosmetic products by gas chromatography-tandem mass spectrometry

A gas chromatography coupled with tandem mass spectrometry (GC-MS/MS) method is developed to determine 18 representative polycyclic aromatic hydrocarbons (PAHs) in cosmetics, including Benzo[a]pyrene (BaP) and others. The method offers high sensitivity and selectivity under selected reaction monitoring (SRM) mode to satisfy the requirements of both quantitation and qualitation. The extraction solvent system used in this study is acetone/hexane 1:1 (v/v) and other purification procedure is unnecessary. The linearities of 18 PAHs are validated in different concentration in the range of 0.25–20 ng/mL individually with coefficient correlation (r) higher than 0.996. The recoveries for spiking 3 different concentrations are from 87.40% to 120.44% for 18 PAHs and the coefficient of variation (CV) are below 12.32%. Limit of quantification (LOQ) of 18 PAHs is in the range of 0.05–0.2 mg/kg. A matrix enhancement effect is observed and can be compensated with deuterated internal standard. The method has been successfully applied to 73 samples, over 40 of them are lipsticks. The results show none of the samples detect Benzo[a]pyrene (BaP) and Dibenzo[a,h]anthracene (DBA), both are classified as the most carcinogenic. 8 PAHs are detected and the average value between 0.08 and 0.27 mg/kg. This study offers a sensitive and simple method to analyze 18 representative PAHs successfully and can be applied to cosmetic products and raw materials.     

液相色谱-电喷雾串联质谱分析人全血中环孢素的基质效应评估及其机理探究

目的： 评估液相色谱-电喷雾串联质谱（LC-ESI-MS/MS）分析人全血中环孢素的基质效应，并探究其发生机理。方法： 全血裂解物的蛋白沉淀上清液用作全血基质。分别用乙腈水溶液和全血基质配制等浓度环孢素A（CyA）、环孢素C（CyC）的质控样品。分别在添加H⁺、NH₄⁺和Na⁺的流动相中，用LC-ESI-MS/MS的MRM模式检测质控样品中CyA，CyC的[M+H]⁺、[M+NH₄]⁺和[M+Na]⁺（M=CyA，CyC）峰面积，以其计算基质效应因子；用MS Scan模式检查质控样品中CyA、CyC色谱流出峰的质谱离子组成情况，用于判断基质效应原因。结果： 在添加H⁺、NH₄⁺和Na⁺的流动相中，全血基质中CyA、CyC基质效应因子分别为-76.6%~-54.0%、-86.0%~-55.3%和-42.8%~-34.1%。在加H⁺、加NH₄⁺流动相中，标准液加全血基质的CyA、CyC色谱峰的质谱中出现丰度很高的[M+Na]⁺和[M+K]⁺，在加Na⁺流动相中它们出现丰度很高的[M+K]⁺，而对应的定量离子[M+H]⁺、[M+NH₄]⁺或[M+Na]⁺的丰度显著降低。结论： 全血基质对环孢素的LC-ESI-MS/MS分析产生明显的基质效应，其原因与基质中Na⁺、K⁺同添加在流动相中用于辅助电离的H⁺、NH₄⁺或Na⁺竞争与环孢素加合，导致定量目标加合离子丰度显著降低有关。     

气相色谱法测定血液中毒鼠强的含量

目的:对血液中的毒鼠强进行提取和检测.方法:采用酸水解及GC/FPD、GC/MS分析的方法,研究酸水解过程中的水解温度、水解强度等方面的影响,并对毒鼠强的GC/MS图谱进行解析,建立了一个定性准确、提取效率高、干扰少的毒鼠强提取分析方法.结果:毒鼠强工作曲线在0.01～0.2μm/μl之间呈线性关系,相关系数r=0.9999.与传统的液-液提取方法相比,血液样品毒鼠强的检出率提高1.69倍.结论:本方法可应用于生物样品中毒鼠强的提取和检测.