人尿中度冷丁及代谢产物的GC/FID及GC/MS分析

建立了尿中度冷丁的GC/FID定量方法。度冷丁在0.1～8μg/ml尿范围内浓度与峰面积比成良好的线性相关,回归方程为Y=0.4995X+0.11201,r=0.9996,最低检测浓度为20ng/m1。该法灵敏、快速、准确。已应用于一例成瘾患者尿中度冷丁的定量测定。并通过GC/MS检测了尿样中度冷丁的主要代谢产物——去甲基度冷丁、去甲基度冷丁酸及其结合物、度冷丁酸及其结合物以及未见文献报道的乙酰基去甲基度冷丁。     

HPLC-MS/MS法测定人血浆中卡马西平浓度的不确定度评定

摘 要 目的： 评定HPLC MS/MS测定人血浆中卡马西平(CBZ)浓度的不确定度。方法: 分析HPLC MS/MS法测定人血浆中CBZ浓度的不确定度来源,计算并进行合成和扩展。结果: 人血浆中低浓度(7.46 ng ·mL^-1)和高浓度(745 ng ·mL^-1)CBZ的扩展不确定度分别为0.410 ng ·mL^-1和33.400  ng ·mL^-1 (P=95%,k=2)。结论:HPLC MS/MS法测定人血浆中CBZ浓度的不确定度在低浓度时主要由回收率、生物样品配制和基质效应引入,在高浓度时主要由生物样品配制和重复性引入。     

LC-MS/MS法测定豚鼠毛发中可卡因及其代谢物苯甲酰爱康宁

本实验旨在建立豚鼠毛发中可卡因及其代谢物苯甲酰爱康宁的液相色谱-串联质谱分析方法，并考察单次给药后豚鼠毛发中可卡因和苯甲酰爱康宁的质量浓度。毛发洗涤、晾干后剪成1～2 mm小段，取20 mg，加入0.1 mol·L^-1 HCl 1 mL和内标溶液(50 ng·mL^-1 D₃-可卡因和D₈-苯甲酰爱康宁) 20 μL，50 ℃水浴中酸水解过夜；调pH为中性，用二氯甲烷液液提取，移取有机相于60 ℃水浴下挥干，用甲醇100 μL复溶，进样5 μL。目标化合物用Allure PFP丙基柱分离，以甲醇-20 mmol·L^-1乙酸铵(0.1%甲酸)(80∶20)为流动相。质谱采用电喷雾电离-正离子模式(ESI+)，多反应监测模式(MRM)。动物实验：豚鼠8只分两组，分别以10和0.4 mg·kg^-1的剂量腹腔注射盐酸可卡因水溶液一次，在给药后d 7和d 14分色剃取毛发进行检测。结果显示，毛发中可卡因和苯甲酰爱康宁的最低检出限均为1 pg·mg^-1，在5～250 pg·mg^-1线性良好(r²≥0.999 7)。在给药后d 7收集的豚鼠毛发中同时检测到可卡因和苯甲酰爱康宁；d 14收集的毛发中只检测到可卡因。所建LC-MS/MS法灵敏度高，特异性强，适用于豚鼠毛发中低质量浓度的可卡因和苯甲酰爱康宁的分析。     

尿中氯胺酮及其代谢物的定性分析

目的:了解氯胺酮在人体内的代谢情况和代谢产物,为检测滥用氯胺酮者尿液提供定性分析手段.方法:用固相萃取及GC/MS的选择性离子模式(SIM)检测尿中氯胺酮及其2种代谢物.结果:运用GC/MS确认了氯胺酮滥用者尿液中的有效成分氯胺铜及其代谢物去甲基氯胺酮和脱氢去甲基氯胺酮.结论:上述方法可以用于滥用者尿中氯胺酮及其代谢物的测定.     

中国人肝微粒体体外代谢奥美拉唑的酶促反应动力学

采用中国成人肝微粒体建立了体外孵育代谢奥美拉唑的酶促反应,应用反相HPLC法测定孵育体系中奥美拉唑的两种主要代谢物羟奥美拉唑和奥美拉唑砜的含量。该方法灵敏度高、简便、快速、可靠。实验结果表明,人肝微粒体主要通过羟化和S原子氧化代谢奥美拉唑。其羟化反应的最大反应速率(Vmax)和米氏常数(Km)分别为42.90 nmol·min^-1·mg^-1和6.49μmol·L^-1,而S原子氧化代谢为6.63nmol·min^-1·mg^-1和11.80μmol·L^-1。消旋美芬妥英、地西泮、去甲西泮及罂粟碱对奥美拉唑体外代谢的实验结果表明,上述药物对奥美拉唑的羟化代谢均有不同程度的抑制作用,其中美芬妥英、地西泮、去甲西泮为奥美拉唑羟化代谢的竞争性抑制剂,罂粟碱为反竞争性抑制剂。同时,这4种药物对奥美拉唑的S原子氧化代谢亦有一定的影响。     

LC/MS/MS的多反应监测方法定量测定灯盏乙素

目的：建立一种可靠的灯盏乙素定量分析方法。方法：用三级四极串联质谱(MS/MS)作为HPLC的检测器,其中MS/MS使用了多反应监测(MRM)扫描方式。选择母→子离子对m/z -461→m/z -285作为MRM监测的离子对;HPLC流动相为100％甲醇,流速0.9 mL.min^-1,色谱柱Beckman ODS-1。以测定短葶飞蓬提取物的灯盏乙素含量为例,对此方法进行了应用。结果：灯盏乙素在短葶飞蓬提取物中含量为6.98%。方法线性范围20～160 ng.mL^-1 (γ=0.999);加入灯盏乙素标准品20,60和160 ng的加样回收率分别为：96.5%,97.4%和97.3%。检测限为1 ng,每个样品的分析时间为4 min。结论：此法灵敏、快速、准确,可应用于灯盏乙素的各种药剂、药代的研究。     

CYP2D6酶活性的毛细管气相色谱法测定及在代谢分型中的应用

目的：建立测定细胞色素CYP2D6酶活性的毛细管气相色谱方法。方法：受试者口服右美沙芬(DM)后收集0～8 h尿样，经提取分离，以HP-1毛细管柱分离，FID为检测器。结果：右美沙芬与代谢物3-羟基-N-甲基-吗喃(DT)分离良好，DM在0.20～1.60 μg.mL^-1，DT在0.40～20.00 μg.mL^-1范围内线性关系良好，回收率分别为99.5%和99.8%，日内相对标准偏差分别小于5.47%和6.19%，DM和DT的最低检测限分别为8 ng和4 ng。用此法对11名健康志愿者进行了CYP2D6活性测定。结论：此法简便、准确，可用于CYP2D6酶活性的测定。     

滥用“摇头丸”的识别和快速检测

为识别和快速检测是否滥用“摇头丸”，本文对“摇头丸”的外观形状，颜色及滥用者的身体表现特征进行总结归纳。并利用气相色谱-氮磷检测器（GC/NPD）及气相色谱-质谱联用（GC/MS）仪对“摇头丸”成分及滥用者的尿样进行快速检测。其最小检出限为0.5ng/ml尿，可以确认嫌疑人一周内是否滥用过“摇头丸”，为法庭毒物学鉴定提供科学依据。     

人血浆中O-去甲右美沙芬的测定及药代动力学研究

目的建立直接测定人血浆中O-去甲右美沙芬的方法,并应用于药代动力学研究。方法18名健康受试者单剂量po氢溴酸右美沙芬60 mg后,血浆样品经液-液萃取,通过液相色谱-质谱-质谱联用法测定其活性代谢物O-去甲右美沙芬的浓度,用非室模型计算药代动力学参数。结果O-去甲右美沙芬测定的线性范围为0.2～80 μg·L^-1;其主要药代动力学参数T_max为(2.1±0.7) h,C_max为(14±8) μg·L^-1,T_1/2为(3.8±1.8) h,用梯形法计算,AUC_0-t为(60±37) μg·h·L^-1。结论该法灵敏度高,操作简便,可直接测定活性代谢物,适用于右美沙芬的临床药代动力学研究及制剂的生物等效性评价。     

五味子醇甲在大鼠肝微粒体内的代谢动力学和性别差异

体外研究五味子醇甲(schizandrin，SZ)在大鼠肝微粒体内的代谢动力学和性别差异。制备正常雌、雄大鼠肝微粒体，与SZ共同温孵，以高效液相色谱法测定SZ及其代谢产物。SZ在雄鼠肝微粒体内代谢反应的最大速率V_max、米氏常数K_m和清除率Cl_int分别为(21.88±2.30) μmol·L^-1·min^-1·mg^-1(protein)，(389.00±46.26) μmol·L^-1和(0.056 3±0.000 7) min·mg^-1(protein)；在雌鼠肝微粒体内代谢反应的最大速率V_max、米氏常数K_m和清除率Clint_{分别为(0.61±0.07) μmol·L^-1·min^-1·mg^-1(protein)，(72.64±13.61) μmol·L^-1和(0.008 4±0.000 8) min·mg^-1(protein)，雌、雄鼠肝微粒体内SZ的主要代谢物不同，分别为7,8-顺二羟基五味子醇甲(M1)和7,8-顺二羟基-2-去甲基五味子醇甲(M2b)。酮康唑、奎尼丁和奥芬得林对SZ的在雌、雄大鼠肝微粒体内代谢均有不同程度的抑制作用，西咪替丁对其在雄鼠肝微粒体内的代谢也有一定的抑制作用。SZ在雌、雄大鼠肝微粒体中代谢动力学及代谢产物存在明显的性别差异，这种差异可能主要是由CYP3A和CYP2C11在大鼠肝微粒体内的性别差异引起的。}     

Hair testing for cocaine and metabolites by GC/MS: criteria to quantitatively assess cocaine use

A simple, rapid and sensitive method has been developed and validated for the determination of cocaine and its main metabolites (benzoylecgonine and cocaethylene) in human hair. The method involved solid‐phase extraction with an Oasis HLB extraction cartridge and subsequent analysis by GC/MS. The limit of detection was 0.01 ng mg^?1 for cocaine, 0.04 for benzoylecgonine and 0.03 for cocaethylene. The method validation included linearity (with a correlation coefficient >0.99 over the range 0.2–50 ng mg^?1), intra‐ and inter‐day precision (always lower than 12%) and accuracy (mean relative error always below 17%) to meet the bioanalytical acceptance criteria. The procedure was further applied to 40 hair samples from self‐reported cocaine users arrested by the police who provided a positive urine‐analysis for cocaine, and was demonstrated to be suitable for its application in forensic toxicology. New approaches were raised to detect false‐negative results that allow a better interpretation of hair testing results. Copyright © 2012 John Wiley & Sons, Ltd.     

Metabolism of meperidine in several animal species

Four new meperidine metabolites were identified by GC-MS in the urine of rats, guinea pigs, rabbits, cats, and dogs. In addition to known meperidine metabolites, 4-ethoxycarbonyl-4-phenyl-1,2,3,4-tetrapyridine (dehydronormeperidine; IV, the N-hydroxydehydro derivative of normeperidine (X), the dihydroxy derivative of meperidine (XII), and the dihydroxy derivative of normeperidine (XIII) were identified. The possible role of the N-hydroxy derivative of normeperidine (IX) in the pharmacological interaction of meperidine (I) with MAO inhibitors, seen selectively in the rabbit (and humans), is discussed. Following the administration of the p-hydroxy derivative of meperidine (VII), the major metabolite was conjugated VII. Trace amounts of the p-hydroxy derivative of normeperidine (VIII), the methoxy hydroxy derivative of meperidine (XI), XII, and XIII also were detected as metabolites of VII. The degree of N-demethylation of VII, both in vitro and in vivo, was small.     

The effect of ritonavir on the pharmacokinetics of meperidine and normeperidine

STUDY OBJECTIVE: To determine the effects of ritonavir on the pharmacokinetics of meperidine and normeperidine. DESIGN: Open-label, crossover, pharmacokinetic study. SETTING: United States government research hospital. SUBJECTS: Eight healthy volunteers who tested negative for the human immunodeficiency virus. INTERVENTION: Subjects received oral meperidine 50 mg and had serial blood samples collected for 48 hours. They then received ritonavir 500 mg twice/day for 10 days, followed by administration of a second 50-mg meperidine dose and collection of serial samples. MEASUREMENTS AND MAIN RESULTS: Plasma samples were assayed for meperidine, normeperidine, and ritonavir. Meperidine's area under the curve (AUC) decreased in all subjects by a mean of 67+/-4% in the presence of ritonavir (p<0.005). Mean +/- SD maximum concentration was decreased from 126+/-47 to 51+/-21 ng/ml. Normeperidine's mean AUC was increased 47%, suggesting induction of hepatic metabolism. CONCLUSION: Meperidine's AUC is significantly reduced, not increased, by concomitant ritonavir. Based on these findings, the risk of narcotic-related adverse effects from this combination appears to be minimal. However, increased concentrations of normeperidine suggest a potential for toxicity with increased dosages or long-term therapy.     

Norcocaine and cocaethylene distribution patterns in hair samples from light,moderate, and heavy cocaine users

Even though hair analysis often seems to be the best choice for retrospective monitoring of cocaine intake, differentiating between incorporated cocaine and external contamination is widely debated. In this study we report results obtained in 90 hair samples from addicts. All samples were analyzed for cocaine, benzoylecgonine, norcocaine, cocaethylene, and tropococaine by gas chromatography‐mass spectrometry (GC‐MS) techniques coupled with direct immersion solid‐phase micro‐extraction. Cocaine concentrations were stratified into three classes of usage: light (0.5–3 ng/mg), moderate (3.1–10 ng/mg) and heavy (10.1–40 ng/mg). The Substance Abuse and Mental Health Services Administration cut‐off criteria for establishing active cocaine use were applied to the results. For all samples criteria were cocaine levels above 0.5 ng/mg (ranging from 1.63 to 39.29 ng/mg, mean 9.49 ng/mg), benzoylecgonine concentrations ≥ 0.05 ng/mg (ranging from 0.19 to 5.77 ng/mg, mean 1.40), and benzoylecgonine to cocaine % ratio ≥5% (from 6.43 to 26.09%). Norcocaine was present in 58.9% of samples (concentration range: 0.22–3.14 ng/mg) and was strongly predictive only of heavy cocaine use (sensitivity 100% for cocaine concentrations above 9.58 ng/mg). Twenty hair samples from moderate and heavy users tested positive for cocaethylene (concentration range: 0.22–1.98 ng/mg, mean 0.73 ng/mg). This study on hair samples with no chance of false positive cases highlights the very limited applications of testing minor cocaine metabolites for definitive proof of active cocaine consumption. © 2015 The Authors. Drug Testing and Analysis Published by John Wiley & Sons, Ltd.     

Determination of fentanyl in whole blood at subnanogram concentrations by dual capillary column gas chromatography with nitrogen sensitive detectors and gas chromatography/mass spectrometry

Two methods for the determination of fentanyl at subnanogram concentrations in whole blood have been developed and evaluated. The initial screening was by gas chromatography with nitrogen sensitive detection (GC/NPD) in a splitless injection onto two fused-silica, 0.32-mm i.d. capillary columns (5% and 50% phenyl methyl silicone). Confirmation was by gas chromatography/mass spectrometry (GC/MS) using selected ion monitoring of a splitless injection onto a 0.1-mm i.d., 0.34-microns 5% phenyl methyl silicone capillary column. The methods were studied at fentanyl concentrations over the range 0.05 to 5.0 ng/mL using 2 mL of blood. The detection limits were set at 0.10 ng/mL for GC/NPD and 0.05 ng/mL for GC/MS. The overall recovery of fentanyl was found to be greater than 75% over the range of 0.25 to 2.5 ng/mL. The within-run precision determined at fentanyl concentrations of 0.25 and 1.0 ng/mL showed coefficients of variation ranging from 8.7 to 14.8%. The between-run precision determined at concentrations of 0.4 and 0.8 ng/mL showed coefficients of variation ranging from 3.3 to 11.6%. The blood calibration curves in the range of 0.25 to 2.5 ng/mL monitored over a 3-month period showed a mean correlation coefficient of 0.99 for both the GC/NPD and GC/MS methods.     

GLC determination of meperidinic and normeperidinic acids in urine

A GLC procedure for the determination of meperidinic and normeperidinic acids in human urine is described. After the extraction of any interfering meperidine or normeperidine, the urine samples are dried and the acids are reesterified using ethanol-sulfuric acid. The resulting meperidine and normeperidine are then extracted and quantified. With this method, the urinary excretion of these metabolites was followed in five subjects who received a single meperidine dose of 36 mg/m2 im. This method represents an improvement over the previously described methods for meperidinic and normeperidinic acids and can be applied to clinical situations.     

Cocaine and metabolite concentrations in the hair of South American coca chewers.

Hair samples obtained from South American Indians who were identified as daily chewers of coca leaves were analyzed by a sensitive gas chromatography/mass spectrometry (GC/MS) method for cocaine, benzoylecognine (BE), and ecognine methyl ester (EME). The mean cocaine concentration in the hair of these five subjects was 15.2 ng/mg hair +/- 11.0 (range = 1.0-28.9 ng/mg), mean BE concentration was 2.8 +/- 1.6 ng/mg hair (range = 0.3-4.4 ng/mg hair), and mean EME concentration was 1.6 +/- 1.7 (range = 0.0-4.4 ng/mg hair). The finding that cocaine was present at approximately 5 times higher concentration than BE and approximately 12 times higher than EME is surprising in light of the much longer plasma half lives of these metabolites. Washing the hair before analysis with 1% dodecyl sulfate, methanol, and distilled water reduced the concentration of cocaine in the hair but also reduced the concentrations of the metabolites. These data suggest that factors other than the drug concentration in blood may be important in determining the amount of drug incorporated into hair.     

CYP2B6, CYP3A4, and CYP2C19 are responsible for the in vitro N-demethylation of meperidine in human liver microsomes.

Meperidine is an opioid analgesic metabolized in the liver by N-demethylation to normeperidine, a potent stimulant of the central nervous system. The purpose of this study was to identify the human cytochrome P450 (P450) enzymes involved in normeperidine formation. Our in vitro studies included 1) screening 16 expressed P450s for normeperidine formation, 2) kinetic experiments on human liver microsomes and candidate P450s, and 3) correlation and inhibition experiments using human hepatic microsomes. After normalization by its relative abundance in human liver microsomes, CYP2B6, CYP3A4, and CYP2C19 accounted for 57, 28, and 15% of the total intrinsic clearance of meperidine. CYP3A5 and CYP2D6 contributed to < 1%. Formation of normeperidine significantly correlated with CYP2B6-selective S-mephenytoin N-demethylation (r = 0.88, p < 0.0001 at 75 > microM meperidine, and r = 0.89, p < 0.0001 at 350 microM meperidine, n = 21) and CYP3A4-selective midazolam 1'-hydroxylation (r = 0.59, p < 0.01 at 75 microM meperidine, and r = 0.55, p < 0.01 at 350 microM meperidine, n = 23). No significant correlation was observed with CYP2C19-selective S-mephenytoin 4'-hydroxylation (r = 0.36, p = 0.2 at 75 microM meperidine, and r = 0.02, p = 0.9 at 350 microM meperidine, n = 13). An anti-CYP2B6 antibody inhibited normeperidine formation by 46%. In contrast, antibodies inhibitory to CYP3A4 and CYP2C8/9/18/19 had little effect (<14% inhibition). Experiments with thiotepa and ketoconazole suggested inhibition of microsomal CYP2B6 and CYP3A4 activity, whereas studies with fluvoxamine (a substrate of CYP2C19) were inconclusive due to lack of specificity. We conclude that normeperidine formation in human liver microsomes is mainly catalyzed by CYP2B6 and CYP3A4, with a minor contribution from CYP2C19.     

Kinetics of meperidine N-demethylation in the perfused rat liver preparation

Meperidine and normeperidine elimination was studied in the once-through perfused rat liver preparation. Biliary excretion of these bases was minimal, and nonlinear metabolism of meperidine (extraction ratio of 1.0 to 0.89 at 1 to 19 micrograms/ml) and normeperidine (extraction ratio of 0.6 to 0.1 at 1 to 25 micrograms/ml) was observed when input concentration was increased. The rate of efflux of normeperidine in hepatic venous blood represented an increasing proportion of the rate of presentation and the rate of loss of meperidine (34 to 92%) at increasing meperidine input concentration. But when the data were corrected for the nonlinear sequential metabolism of normeperidine, the rate of N-demethylation accounted completely for the rate of metabolism of meperidine. These N-demethylation rates obeyed Michaelis-Menten behavior, and appeared to be saturated at input meperidine concentration greater than 5 micrograms/ml.