手性毛细管色谱法测定人尿中美芬妥英对映体的含量及其在代谢分型中的应用

采用手性毛细管色谱柱和ＦＩＤ检测器建立了人尿中美芬妥英（ＭＰ）对映体的定量分析方法。尿样用二氯乙烷提取，用酸、碱洗涤得以纯化，测得各对映体的最低检测限为６０μｇ／Ｌ。在１１５～６９０μｇ／Ｌ浓度范围内，标准曲线呈良好的线性关系，ｒ＞０．９９，日内、日间精密度ＲＳＤ＜６．５％，Ｓ－ＭＰ的平均回收率为７４．４１％，Ｒ－ＭＰ的平均回收率为７３．７８％。并以ＭＰ为探针药物，对３２名志愿者的尿样进行了ＭＰ氧化代谢分型研究。     

氧氟沙星对映体的同步-导数荧光光谱法识别与测定

控制ｐＨ＝３,首次通过同步一阶导数荧光光谱技术,有效地识别和分辨氧氟沙星的Ｒ和Ｓ对映体,是时有效地消除尿样背景的干扰。据此建立了同时识别与测定两种旋光体的同步－导数荧光光谱法,测定尿样中的对映体含量,线性范围为：０．３６￣３１．６ｍｇ／Ｌ（Ｒ）,０．３６￣２．８９ｍｇ／Ｌ（Ｓ）和３．１６￣３１．６ｍｇ／Ｌ（Ｓ）,实际可检测下限均为０．３６ｍｇ／Ｌ,回收率９７％￣１０４％,相对标准偏差小于５％。     

麦地霉素在玻碳电极上的阳极伏安法研究

用线性扫描伏安法（ＩＳＶ）、微分脉冲伏安法（ＤＰＶ）和循环伏安法（ＣＶ）在玻碳电极 （ＧＣＥ）上研究了麦地霉素（ＭＤ）在不同介质中的阳极伏安行为。发现在０．１ｍｏｌ／Ｌ Ｎａ_２ＨＰＯ_４溶 液中于０．７５Ｖ（υｓ． Ａｇ／ＡｇＣｌ）左右产生一个阳极氧化峰,峰高与ＭＤ浓度５ × １０~（－５）～１×１０~－１ｇ／Ｌ 范围内呈线性关系。用本法不需分离直接测定了药物制剂和加标尿样。ＲＳＤ为１．８％（ｎ＝ １０）。尿样中ＭＤ的回收率为９５％～１１５％。实验结果表明ＭＤ的电极氧化反应为不可逆过 程。     

电感耦合等离子体质谱测定铜精矿及废料中痕量锇同位素

样品经过碱熔氧化和蒸馏分离处理,用冰浴水吸收ＯｓＯ４,电感耦合等离子体质谱（ＩＣＰ－ＭＳ）测定纳克量６种Ｏｓ同位素。方法检出限为０．００１８μｇ／Ｌ￣０．０１５μｇ／Ｌ,加标回收率为９３．８％￣１０９．７％。     

聚乙烯醇对锌镉铅溶出增敏作用及应用

在０．０５ｍｏｌ／Ｌ（ｐＨ６．５）乙二妥－盐酸介质中,聚乙烯醇－１２４ＰＶＡ－１２４）对锌,镉,铅的电位溶出有显著的增敏作用。当富集６０ｓ时,其检出限均达６．０μｇ／Ｌ,线性范围：锌０．６－３５μｇ／Ｌ,镉０．６－４５μｇ／Ｌ,铅０．６－５０μｇ／Ｌ。标准加入回收率为９２．４％－１１０％。ＲＳＤ（ｎ－４）〈７．０％。     

毛细管气相色谱法测定速效伤风胶囊中对乙酰氨基酚、咖啡因、马来酸氯苯那敏的含量

用５％Ｐｈ－Ｍｅ－Ｓｉｌｉｃｏｎｅ毛细管色谱柱，ＦＩＤ，二阶程序升温，以正十六烷作为内标物测定速效伤风胶囊中对乙酰氨基酚、咖啡因、马来酸氯苯那敏的含量。浓度线性范围：对乙酰氨基酚４～２０ｇ／Ｌ，咖啡因０．０８４～０．４２ｇ／Ｌ，马来酸氯苯那敏０．１５～０．７５ｇ／Ｌ。平均回收率（ｎ＝５）：对乙酰氨基酚９９．６２％（ＲＳＤ＝０．４４％）咖啡因９６．４６％（ＲＳＤ＝１．３２％），马来酸氯苯那敏９８．５５％（ＲＳＤ＝０．６５％）。     

微克级介形虫壳体样品的多元素ICP－AES同时测定

本文从顺序扫描式双通道电感耦合等离子体原子发射光谱仪（ＩＣＰ－ＡＥＳ）的特点出发，对微克级介形虫壳体样品中的低含量元素选择最灵敏谱线和最佳通道，对各项条件进行最优化。Ｍｇ、Ｓｒ、Ｍｎ、Ｆｅ、Ｂａ、Ｚｎ的检测限分别为０．６～５．２μｇ／Ｌ，Ｃａ和Ｎａ的检测限分别为１６μｇ／Ｌ和５２μｇ／Ｌ，测定了微克级样品的多元素含量，回收率为９０％～１０６％。     

毛细管气相色谱法测定速效伤风胶囊中对乙酰氨基酚、咖啡因、马来酸氯苯那敏的含量

 用５％Ｐｈ－Ｍｅ－Ｓｉｌｉｃｏｎｅ毛细管色谱柱，ＦＩＤ，二阶程序升温，以正十六烷作为内标物测定速效伤风胶囊中对乙酰氨基酚、咖啡因、马来酸氯苯那敏的含量。浓度线性范围：对乙酰氨基酚４～２０ｇ／Ｌ，咖啡因０．０８４～０．４２ｇ／Ｌ，马来酸氯苯那敏０．１５～０．７５ｇ／Ｌ。平均回收率（ｎ＝５）：对乙酰氨基酚９９．６２％（ＲＳＤ＝０．４４％）咖啡因９６．４６％（ＲＳＤ＝１．３２％），马来酸氯苯那敏９８．５５％（ＲＳＤ＝０．６５％）。     

微克级介形虫壳体样品的多元素ICP—AES同时测定

本文从顺序扫描式双通道电感耦合等离子体原子发射光谱仪（ＩＣＰ－ＡＥＳ）的特点出发，对微克级介形虫壳体样品中的低含量元素选择最灵敏谱线和最佳通道，对各项条件进行最优化。Ｍｇ，Ｓｒ，Ｍｎ，Ｆｅ，Ｂａ，Ｚｎ的检测限分别为０．６～５．２μｇ／Ｌ，Ｃａ和Ｎａ的检测限分别为１６μｇ／Ｌ和５２μｇ／Ｌ，测定了微克极样品的多元素含量，回收率为９０％～１０６％。     

气相色谱/质谱法测定大鼠脑中5-羟色胺的含量

采用气相色谱／质谱法（ＧＣ／ＭＳ）测定了正常大鼠和服药大鼠脑组织中５－羟色胺（５－ＨＴ）的浓度。大鼠脑组织制成匀浆后,先将５－ＨＴ酰化,酰化物经乙酸乙酯提取后,再经七氟丁酸酐衍生化,用ＧＣ／ＭＳ测定。ＭＳ采用电子捕获负离子化学电离（ＥＣＮＩＣＩ）模式。方法的线性范围为０．５０～５０．０μｇ／Ｌ,回归方程为Ｙ＝０．１３４８Ｘ－０．０７９９５（ｒ＝０．９９９６）;平均回收率为９８．２％±３．８％（ｎ＝１０）;检测限为０．５μｇ／Ｌ;相对标准偏差小于１０％。     

Stereoselective analysis of the enantiomers of mexiletine by high-performance liquid chromatography using fluorescence detection and study of their stereoselective disposition in man

A sensitive, stereoselective high-performance liquid chromatographic assay was developed for the resolution of the enantiomers of mexiletine as their 2-naphthoyl derivatives on a Pirkle type 1A chiral phase column. Detection of the derivatives was accomplished with a fluorescent detector. Maximum recovery of the enantiomers from plasma was 83% and was observed when plasma proteins were precipitated with a mixture of barium hydroxide-zinc sulphate. The calibration curve in plasma was linear over the concentration range 5-750 ng/ml for each enantiomer (r2 = 0.999) and in urine the linear range was 0.25-7.5 micrograms/ml (r2 = 0.999) for each enantiomer. The minimum detectable quantity of each enantiomer in plasma was 5 ng/ml at a signal-to-noise ratio of 5:1, representing 100 pg injected. A preliminary pharmacokinetic study was undertaken in one healthy male volunteer following an oral dose of 300 mg of racemic mexiletine hydrochloride. The apparent elimination half-lives determined from the plasma data were 12.1 and 14.1 h for the R(-) and S(+) enantiomers, respectively. The cumulative urinary excretion amounts of R(-)- and S(+)-mexiletine were found to be 8.01 and 10.46 mg, respectively. The plasma data indicated that a cross-over of the enantiomer ratios occurred at approximately 8 h. The urinary excretion of the enantiomers was consistent with the pattern found in plasma.     

Direct enantiomeric resolution of disopyramide and its metabolite using chiral high-performance liquid chromatography. Application to stereoselective metabolism and pharmacokinetics of racemic disopyramide in man

A method for the simultaneous determination of disopyramide and mono-N-desisopropyldisopyramide enantiomers extracted from human plasma and urine is presented. Separation and quantitation were carried out using two columns coupled in series, and UV detection at 254 nm. First, the racemates of the two compounds were separated using a reversed-phase column, and then the enantiomers were separated using a stereoselective column packed with human alpha 1-acid glycoprotein. The mobile phase was 8 mM phosphate buffer, pH 6.20-2-propanol (92:8, v/v). The coefficients of variation (%) for the plasma daily determination were 6.7% for R(-)- and S(+)-disopyramide at drug levels of 1.5 micrograms/ml, and 8.5% and 7.7% for R(-)- and S(+)-mono-N-desisopropyldisopyramide, respectively, at drug levels of 0.375 micrograms/ml. The method has allowed the study of stereoselective metabolism and pharmacokinetics of disopyramide after oral administration as a racemate.     

Multiple inverse isotope dilution assay for the stereospecific quantitative determination of R(-) and S(+)-oxaprotiline in biological fluids

An isotope dilution assay for the determination of both oxaprotiline enantiomers in biological samples after administration of the racemic mixture has been developed. The enantiomers were reacted with synthetically prepared, optically pure N-trifluoroacetyl-S(-)-prolyl chloride, followed by high-performance liquid chromatographic separation of the diastereoisomers formed. Quantitation was performed by on-line UV detection at 260 nm and off-line radiometry by liquid scintillation counting. Endogenous compounds and metabolites do not interfere in the assay. Analysis of water and the blood and urine of rats spiked with [14C]oxaprotiline X HCl showed recoveries for S(+)-oxaprotiline X HCl (mean +/- coefficient of variation, n = 4-6) of 98.0 +/- 1.0% (water), 100.5 +/- 0.6% (blood) and 101.5 +/- 2.0% (urine), and for R(-)-oxaprotiline X HCl of 101.3 +/- 2.0% (water), 102.2 +/- 2.1% (blood) and 103.2 +/- 0.2% (urine). A pilot study to determine blood levels of the two enantiomers in two rats dosed with racemic [14C]oxaprotiline X HCl (10 mg/kg i.v.) was carried out to test the method. The results indicated stereoselective disposition of oxaprotiline enantiomers in the rat. The ratio of the areas under the blood concentration curves for R(-)-to S(+)-oxaprotiline X HCl was 1.14.     

Phenotype analysis of cytochrome P450 2C19 in Chinese subjects with mephenytoin S/R enantiomeric ratio in urine measured by chiral GC

A chiral gas chromatographic method with FID was developed for the determination of S- and R-mephenytoin in human urine. The assay is linear from 25 to 800 ng/mL for each enantiomer and the limit of detection and limit of quantitation were 12 and 25ng/mL for each enantiomer, respectively. The method affords average recoveries of 74.41 +/- 3.93% and 73.78 +/- 3.02% for S- and R-mephenytoin, respectively. The method allows the phenotype study of CYP2C19 in Chinese subjects. The phenotype pattern of 90 Chinese volunteers was determined, in which 26 volunteers received phenotyping and genotyping tests. The results of phenotype analysis showed that the interindividual variation was marked. The mephenytoin S/R enantiomeric ratios in urine of 11 volunteers were > or = 0.95 and identified as poor metabolizers. The frequency of poor metabolizers was 12.2% in the Chinese subjects tested. A good relationship between phenotype and genotype analysis of CYP2C19 was observed.     

手性荧光衍生化反相高效液相法分离肾上腺素对映体

 以R (- ) /S (+) 4 (N ,N dimethylaminosulfonyl) 7 (3 iso thiocyanatopyrrolidino) 2 ,1,3 benzoxadiazole(DBD PyNCS)为手性荧光衍生化试剂 ,用反相高效液相法 (RP HPLC)对 DL 肾上腺素对映体进行分离。衍生化反应是在含有 7%吡啶的溶剂中 ,6 5℃温度条件下反应 35min ,生成具有荧光特性的肾上腺素非对映体衍生物(λex=4 6 0nm ,λem=5 5 0nm)。生成的非对映体衍生物在流动相为乙腈 水 (体积比为 2 8∶72 ) ,流速为 1 0mL/min时 ,在DiamonsilTMC18柱 (15 0mm× 4 6mmi d ,5 μm)上分离度可达 2 6。     

Determination of mephenytoin stereoselective oxidative metabolism in urine by chiral liquid chromatography employing beta-cyclodextrin as a mobile phase additive.

A direct high-performance liquid chromatographic assay was developed for the separation and determination of S- and R-mephenytion enantiomers in human urine. Separation was achieved on a Supelcosil LC-8 column with methanol-0.1 M acetate buffer as the mobile phase and beta-cyclodextrin as a mobile phase additive. The urinary S/R enantiomeric ratio of mephenytoin was measured in a 32-h urine sample (as phenotypic traits) for determination of the ability of normal subjects to hydroxylate racemice mephenytoin after oral administration of the drug.     

High-throughput chiral analysis of albuterol enantiomers in dog plasma using on-line sample extraction/polar organic mode chiral liquid chromatography with tandem mass spectrometric detection

An automated chiral chromatography/tandem mass spectrometry bioanalytical method for the determination of albuterol in dog plasma was developed. The method employed on-line sample extraction using turbulent flow chromatography coupled to a Chirobiotic T column for chiral separation using a polar organic mobile phase consisting of methanol, 0.02% formic acid, and 0.1% ammonium formate. The analytes were detected by a tandem mass spectrometer operated in positive ion mode. The (S)- and (R)-isomers were resolved chromatographically with retention times of 5.1 and 5.6 min, respectively. The analytical run time was 8 min. The enantiomers did not interconvert either in mobile phase or in dog plasma at room temperature over the course of at least 2 h. The assay has a linear dynamic range from 2.5-2500 nM for both enantiomers. The lower limit of quantitation (LLOQ) was 2.5 nM for both enantiomers using 50 microL of plasma. The accuracy and precision of intraday validation were determined at five concentration levels of six replicates. The accuracy of the method for the (R)-isomer ranged from 94-103% of nominal concentrations, and the precision (%CV) ranged from 3.6-12%. The accuracy of the method for the (S)-isomer ranged from 94.5-108% of nominal concentrations, and the precision ranged from 3.2-9.3%. Interday accuracy and precision were evaluated for three days at five concentrations for one replicate. The accuracy of the method for the (R)-isomer ranged from 98-110% of nominal concentrations, and the precision ranged from 1.5-10.6%. The accuracy of the method for the (S)-isomer ranged from 96-104% of nominal concentrations, and the precision ranged from 1.5-8.7%. The combination of turbulent flow on-line sample extraction with polar organic mode chiral chromatography provided a specific, rugged, and high-throughput method for the chiral analysis of albuterol in biological fluids.     

Enantioselective analysis of pheniramine in urine by charged CD-mediated CZE provided with a fiber-based DAD and an on-line sample pretreatment by capillary ITP

Application potentialities of CZE on-line coupled with capillary ITP and DAD to the identification and determination of trace concentration levels (microg/L) of pheniramine (PHM) enantiomers and their metabolites present in complex ionic matrices of biological origin (urine) are shown. An enhanced (enantio)selectivity of the CZE separation system obtained by the addition of carboxyethyl-beta-CD (CE-beta-CD) to the carrier electrolyte provided CZE conditions for a reliable identification of similar/identical DAD spectra of structurally related compounds (PHM enantiomers and their metabolites) in clinical urine samples differing in qualitative and quantitative composition of sample matrix constituents. A high sample loadability (a 30 microL sample injection volume), partial sample clean-up (removing macroconstituents from the sample), and preconcentration of the analytes in ITP stage resulted in the decrease of concentration LOD for PHM enantiomers in urine to 5.2 and 6.8 microg/L (2.2 x 10(-8) and 2.8 x 10(-8) mol/L), without using any sample pretreatment technique. The background correction and smoothing procedure applied to the raw DAD spectra provided analytically relevant DAD spectra of PHM enantiomers and their metabolites also when they were present in urine sample (30 microL injection volumes of ten-times diluted urine sample) at a 9 x 10(-) (8) mol/L concentration. DAD spectra of PHM enantiomers present in urine samples matched their reference spectra with reasonable certainties. DAD spectra of PHM metabolites were compared with the reference spectra of PHM enantiomers and a good match was found which indicates the similarities in the structures of enantiomers and their metabolites detected in the urine samples. This fact allows performing the quantitative analyses of PHM metabolites in the urine samples by applying the calibration parameters of PHM enantiomers also for PHM metabolites and the results show the possibilities of using the ITP-CZE-DAD combination for the direct analysis of PHM enantiomers and/or their metabolites in urine without any sample pretreatment. ITP-CZE-DAD method with oppositely charged selector is suggested to use in clinical research as it provides favorable performance parameters including sensitivity, linearity, precision, recovery, and robustness with minimal demands on sample preparation.     

A stereospecific high-performance liquid chromatographic assay for the determination of ketoconazole enantiomers in rat plasma

A stereospecific high-performance liquid chromatographic assay was developed for the quantitation of ketoconazole enantiomers (KTZ) in rat plasma. After protein precipitation of 100 microL plasma using acetonitrile, a wash step was performed using hexane. The supernatant was removed and KTZ enantiomers and amiodarone, the internal standard, were extracted using liquid-liquid extraction with tert-butyl methyl ether. After transfer and evaporation of the organic layer, the residue was reconstituted in mobile phase and injected into the HPLC through a chiral column. The mobile phase consisted of hexane:ethanol:2-propanol with diethyl amine, pumped at 1.5 mL/min. All components eluted within 18 min. KTZ enantiomers were baseline resolved and peaks were symmetrical in appearance with no interferences. Calibration curves were linear over the range 62.5-5000 ng/mL of enantiomer. The intraday and interday CV% assessments were 相似文献   

Stereoselective analysis of flecainide enantiomers using reversed‐phase liquid chromatography for assessing CYP2D6 activity

Stereoselective analyses of flecainide enantiomers were performed using reversed‐phase high‐performance liquid chromatography (HPLC) equipped with a polysaccharide‐based chiral column (Chiralpak AS‐RH) and fluorescence detector. Excitation and emission wavelengths were set at 300 and 370 nm, respectively. Flecainide enantiomers in serum and urine were extracted using diethyl ether. The mobile phase solution, comprising 0.1 m potassium hexafluorophosphate and acetonitrile (65:35, v/v), was pumped at a flow rate of 0.5 mL/min. The recoveries of flecainide enantiomers were greater than 94%, with the coefficients of variation (CVs) <6%. The calibration curves of flecainide enantiomers in serum and urine were linear in the concentration range 5–500 ng/mL and 0.75–15 µg/mL (r > 0.999), respectively. CVs in intra‐day and inter‐day assays were 1.8–5.8 and 3.4–7.5%, respectively. In a pharmacokinetic study, the ratios of (S)‐ to (R)‐flecainide (S/R ratio) in the area under the curve and the amount of flecainide enantiomers excreted in urine were lower in a subject carrying CYP2D6*10/*10 than in subjects carrying CYP2D6*1/*2. The S/R ratio of trough serum flecainide concentration ranged from 0.79 to 1.16 in patients receiving oral flecainide. The present HPLC method can be used to assess hepatic flecainide metabolism in a pharmacokinetic study and therapeutic drug monitoring. Copyright © 2014 John Wiley & Sons, Ltd.