Quantitative analysis of the immunosuppressant CP-690,550 in whole blood by column-switching high-performance liquid chromatography and mass spectrometry detection

A fast and accurate method to quantify the new immunosuppressive JAK3 inhibitor CP-690,550 in whole blood using a dual-pump liquid chromatography-liquid chromatography-mass spectrometry (LC/LC-MS) system was developed and validated in nonhuman primate blood. Before injection, blood samples were prepared by precipitation with a reagent that included methanol and acetonitrile (30:70, vol/vol) along with the internal standard (CP-istd). Column-switching LC/LC-MS analysis used online extraction followed by separation on a C8 analytic column and MS detection of the [M + H] CP-690,550 (m/z = 313.1) and CP internal standard (m/z = 288.1). Linearity was always better than r = 0.99 (n = 7) for CP-690,550 (range 2.5-750 ng/mL), with a lower limit of quantification (LLOQ) of 2.5 ng/mL. The intrarun accuracy and precision ranged from 103.0% to 105.4% and 2.7% to 4.3%, respectively (n = 5), and the interday precision ranged from 8.7% to 11.1%, and the interday accuracy ranged from 98.1% to 103.8% of nominal values (n = 14). The injection repeatability for the method was 1.3% (n = 7). Except for the LLOQ, the intraday accuracy and precision in human blood were also within 15% (n = 5). The combination of simple sample preparation and short analytic run time of this sensitive procedure makes it effective for monitoring the concentration of CP-690,550 in whole blood in organ-transplant recipients.     

Rapid and simultaneous measurement of midazolam, 1'-hydroxymidazolam and digoxin by liquid chromatography/tandem mass spectrometry: application to an in vivo study to simultaneously measure P-glycoprotein and cytochrome P450 3A activity

In order to simultaneously determine in vivo P-glycoprotein (P-gp) and Cytochrome P450 3A (CYP3A) activity, a new, rapid and sensitive liquid chromatography/tandem mass spectrometry (LC-MS/MS) method has been developed and fully validated to simultaneously determine midazolam (MDZ, as CYP3A substrate), 1'-hydroxymidazolam (1'-OHMDZ) and digoxin (DG, as P-gp substrate) in rat plasma using digitoxin as the internal standard (IS). After a single step liquid-liquid extraction with tert-butyl methyl ether/dichloromethane (75:25, v/v), analytes were subjected to LC-MS/MS analysis using positive electro-spray ionization (ESI(+)) under selected reaction monitoring mode (SRM). Chromatographic separation was performed on an XTerra MS C18 column (50mm×2.1mm, i.d. 3.5μm). The MS/MS detection was conducted by monitoring the fragmentation of 326.05 → 244.00 (m/z) for MDZ, 342.02 →168.01 (m/z) for 1'-OHMDZ, 798.33 → 651.36(m/z) for DG and 782.67 → 635.24 (m/z) for IS. The method had a chromatographic running time of 3min and linear calibration curves over the concentrations of 2-400ng/mL for MDZ and 1'-OHMDZ and 0.5-100ng/mL for DG. The recoveries of the method were 86.8-96.3% for MDZ, 84.6-86.4% for 1'-OH MDZ, and 81.7-85.1% for DG. The lower limit of quantification (LLOQ) of the method was 2ng/mL for MDZ and 1'-OHMDZ and 0.5ng/mL for DG. The intra- and inter-batch precision were less than 15% for all quality control samples at concentrations of 5, 50 and 320ng/mL for MDZ and 1'-OHMDZ and 1, 10 and 80ng/mL for DG. The validated LC-MS/MS method has been successfully used to analyze the concentrations of MDZ, 1'-OH MDZ and DG in rat plasma for simultaneous measurement of in vivo P-gp and CYP 3A activity.     

Sensitive, high throughput HPLC-MS/MS method with on-line sample clean-up for everolimus measurement

A new HPLC-MS/MS method for everolimus measurement was developed that includes the following features: small sample volume, short run time, fast, simple and cost-efficient sample preparation, assessment of performance of two internal standards (IS), SDZ RAD 223-756 and ascomycin and comparison of the method with an HPLC-MS/MS reference method. The authors established a multiple reaction monitoring positive ion HPLC-MS/MS method with on-line extraction and sample cleanup. This procedure includes: an API 2000 triple quadrupole mass spectrometer with turbo-ion spray, built-in Valco switching valve, an HPLC system; guard column; a Nova-Pak C18 analytical column; washing solution, methanol:30 mM ammonium acetate pH 5.1 (80:20); eluting solution, methanol:30 mM ammonium acetate pH 5.1 (97:3); flow rate 0.8 mL/min; and a run time of 2.8 minutes. The first and third quadrupoles were set to detect the ammonium adduct ion and a high mass fragment of everolimus (m/z 975.5-->908.5), and two ISs: SDZ RAD 223-756 (m/z 989.8-->922.8) and ascomycin (m/z 809.5-->756.5). The LLOQ was 1.0 microg/L for everolimus using either IS. Between day precision ranged from 3.1% to 5.7% for SDZ RAD 223-756 and 6.0% to 8.6% for ascomycin using spiked blood with everolimus concentrations 2.0 to 25.0 microg/L. Absolute recoveries using spiked samples over the range of 2.5 to 25 mug/L averaged 77.3% (SDZ RAD 223-756) and 76.8% (ascomycin). No matrix effect on everolimus was demonstrated based on the mean observed signal detection of 98.6% (SDZ RAD 223-756) and 105% (ascomycin). Comparison of everolimus concentrations obtained using this method with two internal standards with a reference laboratory demonstrated that the mean everolimus concentration obtained with ascomycin was statistically different (lower) than results with the reference method and the method that used SDZ RAD 223-756 as the internal standard gave equivalent results compared with the reference method.     

人血浆中卡巴拉汀及其代谢物NAP226-90的LC-MS/MS测定研究

目的：建立LC-MS/MS法同时检测卡巴拉汀及其代谢物NAP226-90血药浓度。方法：血浆经甲基叔丁基醚-二氯甲烷提取预处理,用Phenomenex-curocil PFP（250 mm×4.6 mm,5μm）色谱柱,0.1%甲酸0.05%甲酸铵溶液-0.1%甲酸0.05%甲酸铵甲醇为流动相,梯度洗脱分离,ESI正离子化三重四极杆质谱MRM测定,检测反应离子对：卡巴拉汀m/z 251.0→206.0、NAP226-90 m/z 166.0→121.0、内标（美托洛尔）m/z 268.4→74.3。结果：卡巴拉汀及NAP226-90血药浓度在0.2～30 ng·mL-1范围内均线性关系良好,定量下限均为0.2 ng·mL-1,经方法学验证符合生物样品测定要求。结论：建立的LC-MS/MS方法可用于重酒石酸卡巴拉汀胶囊人体药动学研究。     

Quantification of N-acetyl-seryl-aspartyl-lysyl-proline in hemodialysis patients administered angiotensin-converting enzyme inhibitors by stable isotope dilution liquid chromatography-tandem mass spectrometry

We developed a sensitive, selective and accurate method based on liquid chromatography with tandem mass spectrometry (LC-MS/MS) to determine N-terminal thymosin-β peptides of Ac-SDKP and Ac-ADKP in human plasma samples. Quantification of Ac-SDKP and Ac-ADKP was performed using solid phase extraction (SPE) based on C(18), reversed phase LC separation, and stable isotope dilution electrospray ionization-MS/MS in multiple reaction-monitoring (MRM) mode. The Ac-SDKP-(13)C(6), (15)N(2) and Ac-ADKP-d(7) were synthesized for the internal standards. These MRM monitoring ions were m/z 488→129 (quantitative ion)/226 for Ac-SDKP, m/z 496→137 for Ac-SDKP-(13)C(6), (15)N(2), m/z 472→129 (quantitative ion)/226 for Ac-ADKP, and m/z 479→129 for Ac-ADKP-d(7), respectively. Lower limit of quantitation (LLOQ) of Ac-SDKP and Ac-ADKP was 0.1ng/mL in human plasma. Recovery values were ranged from 94.7% to 106.3% for inter- (RSD: 0.6-3.5%) and intra- (RSD: 0.4-4.9%) day assays. Plasma Ac-SDKP levels were significantly higher in hemodialyzed subjects treated with angiotensin-converting enzyme inhibitors of enalapril (27.3±24.6ng/mL, n=10) and trandolapril (12.3±16.9ng/mL, n=18) than healthy (0.4±0.2ng/mL, n=7) and hemodialyzed subjects (0.6±0.2ng/mL, n=34). This analytical method would be useful to measure N-terminal thymosin-β peptides in human plasma for the clinical study.     

LC-MS／MS法测定全血中他克莫司浓度的方法学研究

目的：建立测定人全血中他克莫司液相色谱-串联质谱联用（LC-MS／MS）方法,并与微粒子免疫分析（MEIA）方法测定的结果进行了比较。方法：运用LC-MS／MS方法,血样经乙腈沉淀蛋白,上清液氮气吹干流动相复溶进样。色谱柱：Zorbax Extend—C18柱（150mm×4．6mm,5μm）;流动相：甲醇-乙腈-20mmol·L^-1醋酸胺溶液（80：15：5）;流速：0．4ml·min^-1。采用电喷雾离子化四极杆串联质谱,多反应检测方式测定样品的浓度。检测离子对分别为m／z821．7→m／z 768．4和m／z 821．7→m／z 786．5。结果：他克莫司在0．5～128ng·ml^-1浓度范围内,峰面积与浓度线性关系良好（r=0．9991,／2=5）,最低定量限为0．5ng·ml^-1,平均回收率为99．0％,日内精密度、日间精密度的RSD分别为3．38％和4．16％。MEIA分析采用标准IMX测定方法。两种方法比较,其标准差小于3．0,表明相关性好。结论：本方法具有良好的灵敏度、准确度、精确度及专属性,可用于他克莫司血药浓度监测和人体药药动力学研究。     

LC-MS/MS法测定抑郁症患者晨尿中9种氨基酸类内源性物质的浓度

目的:建立测定人体尿液中5-羟基吲哚乙酸、谷氨酰胺、马尿酸、庚二酸、脯氨酸、酪氨酸、色氨酸、酪胺、缬氨酸浓度的方法。方法:采集抑郁症患者的晨尿,加入内标可的松,以乙腈处理后取上清液进行浓缩,采用液相色谱-质谱串联法(LC-MS/MS)进行分析。色谱柱为XTerra RP18;流动相A相为0.1%乙酸-水,流动相B相为0.1%乙酸-乙腈(梯度洗脱);柱温为40℃;流速为0.45mL/min;采用电喷雾离子源(ESI),以多反应监测方式(MRM)进行定量分析,5-羟基吲哚乙酸、谷氨酰胺、马尿酸、庚二酸、脯氨酸、酪氨酸、色氨酸、酪胺、缬氨酸和内标可的松在正离子模式下定量分析离子对分别为质荷比(m/z)192.2→146.1、147.2→130.0、180.1→105.1、161.1→125.2、116.1→70.2、205.2→188.2、138.2→121.1、182.0→123.0、118.2→72.1、361.2→163.0。结果:5-羟基吲哚乙酸、谷氨酰胺、缬氨酸、庚二酸、脯氨酸、酪胺的检测质量浓度范围为10.00~3 200 ng/mL(r=0.993 8~0.998 9,n=6),定量下限为10 ng/mL;色氨酸、酪氨酸、马尿酸的检测质量浓度范围为1 600~51 200 ng/mL(r=0.999 2~0.999 7,n=6),定量下限为1 600ng/mL,准确度试验结果为86.29%~98.65%(n=6),日内、日间精密度试验的RSD均不高于14.65%(n=6),基质效应的CV为6.18%~14.37%(n=6),提取回收率为86.21%~98.14%(n=6),稳定性试验的RE均<14.71%(n=3~6)。结论:该方法灵敏、准确,可用于测定人体内上述9种物质的浓度。     

Determination of diethylstilbestrol in human plasma using high performance liquid chromatography-tandem mass spectrometry

A sensitive, fast, and reproducible high performance liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for the determination of diethylstilbestrol in human plasma was developed and validated. The plasma samples were pretreated by direct deproteinization with ethyl acetate. Daidzein was used as the internal standard. The separation was carried out on a Agilent Technologies 1200 series XDB C₁₈ column (2.1 mm×150 mm, 5 µm) with a mobile phase of acetonitrile-2.5 mmol/L ammonium acetate (60:40, v/v). Triple quadrupole mass spectrometric detection in negative ion mode was used for multiple-reaction-monitoring of the transitions atm/z 267.2→237.3 and m/z 253.2→132.3 for diethylstilbestrol and daidzein, respectively.The calibration curves were linear over the concentration range from 0.1 to 20 ng/mL (r² = 0.9984). The lower limit of quantificationwas 0.1 ng/mL (s/n mLs)for diethylstilbestrol, which was sensitive enough to perform pharmacokinetic studies after diethylstilbestroladministration. Inter-day and intra-day precisions were no more than 7% with accuracies of 90%-105%. This method could be applied to therapeutic drug monitoring of diethylstilbestrol, which is helpful for evaluating the clinical efficacy and safety of diethylstilbestrol.     

液相色谱-串联质谱法同时测定人血浆中二甲双胍和格列吡嗪

建立了快速、灵敏的液相色谱-串联质谱法测定人血浆中的二甲双胍和格列吡嗪。血浆样品经0.3%甲酸-乙腈(v/v)沉淀蛋白后，以乙腈-水-甲酸(70∶30∶0.3，v/v/v)为流动相，流速为0.50 mL·min^-1。Zorbax Extend C₁₈柱分离，采用大气压化学电离源；以选择反应监测(SRM)方式进行正离子检测。用于定量分析的离子反应分别为m/z 130→m/z 60(二甲双胍)，m/z 446→m/z 321(格列吡嗪)和m/z 256→m/z 167(内标，苯海拉明)。测定血浆中二甲双胍的线性范围为2.00～2 000 ng·mL^-1， 定量下限为2.00 ng·mL^-1； 格列吡嗪的线性范围为1.00～1 000 ng·mL^-1， 定量下限为1.00 ng·mL^-1。该方法专属性好，灵敏度高，准确快捷，适用于二甲双胍和格列吡嗪的临床药代动力学研究。     

Development and validation of a sensitive LC/MS-MS method for the determination of letrozole in nude mice plasma and its application to a pharmacokinetic study

A sensitive, rapid and simple liquid chromatography-tandem mass spectrometric (LC-MS/MS) method was developed and validated for the determination of letrozole (LTZ) in nude mouse plasma in the current study, which was successfully applied to a pharmacokinetic study. Using anastrozole as internal standard (IS), plasma samples went through a one-step protein precipitation with acetonitrile before determination. The analyte and IS were analyzed on a reversed-phase ZORBAX-SB-C₁₈column (4.6 mm×250 mm, 5 μm) with an isocratic mobile phase consisting of acetonitrile and water containing 0.1% formic acid (v/v) at a flow rate of 1.0 mL/min. The analyte and IS were detected by a triple-quadrupole tandem mass spectrometer, and electrospray and multiple reaction monitoring (MRM) were employed to select LTZ at m/z 286.4/217.1 and IS at m/z 294.1/225.3 simultaneously in the positive ion mode. The calibration curve showed good linearity ranging from 0.8–2000.0 ng/mL (r>0.99). The intra-day and inter-day precisions of LTZ were 4.0%–8.4%, with an accuracy of 98.6%–104.9%. Using this method, we successfully characterized the pharmacokinetics (PK) of LTZ by a one-compartment model with first-order absorption in female BALB/c nude mice.     

Development and validation of a high-throughput assay for quantification of the proliferation inhibitor ABT-578 using LC/LC-MS/MS in blood and tissue samples

We report here a specific, automated LC/LC-MS/MS assay for the quantification of ABT-578 in human and rabbit blood and rabbit tissues for drug-eluting stent development. After protein precipitation, samples were injected into the HPLC system and extracted online using a high flow of 5 mL/min. The extracts were then backflushed onto the analytic column. The [M+Na] of ABT-578 (m/z 988.6-->369.4) and its internal standard sirolimus (m/z 936.5-->409.3) were monitored. Extraction and analysis took 4 minutes. The assay was validated following the US Food & Drug Administration guidelines. Linearity was 0.025-25 ng/mL for most matrices. In human blood, interday accuracies were 81.8% (at 0.025 ng/mL), 91.0% (1 ng/mL), and 99.5% (50 ng/mL), and interday precisions were 10.7% (0.025 ng/mL), 3.0% (1 ng/mL), and 1.8% (50 ng/mL).     

微透析联合LC-MS/MS法研究马钱子总碱囊泡凝胶透皮吸收

目的:建立皮肤微透析采样技术联合LC-MS/MS同时测定马钱子碱和士的宁的分析方法,并研究大鼠经皮给予马钱子囊泡凝胶后的透皮吸收。方法:应用皮肤微透析技术对大鼠给药部位皮下进行采样;微透析样品以他克林为内标,不经预处理直接进样;色谱采用XDB-C18柱,甲醇-乙腈-水(含0.05%甲酸和10 nmol·L-1甲酸铵)梯度洗脱;质谱采用正离子扫描多反应监测(MRM)方式。,用于定量的离子对分别为m/z 335.2→m/z 184.2(士的宁),m/z 395.2→m/z 324.2(马钱子碱),m/z 199.1→m/z 171.1(他克林)。结果:测定微透析样品中马钱子碱和士的宁2种成分的线性范围分别为0.195～50 ng.mL-1和0.156～40 ng.mL-1,日内和日间精密度(RSD)均小于15%,准确度、稳定性符合要求。结论:该方法操作简便、灵敏度高、专属性强,适用于皮肤微透析样品中马钱子碱和士的宁的测定。     

Liquid chromatographic-tandem mass spectrometric method for the simultaneous quantitation of telmisartan and hydrochlorothiazide in human plasma

A rapid and sensitive method using liquid chromatography-tandem mass spectrometry (LC-MS/MS) has been developed for the simultaneous determination of telmisartan and hydrochlorothiazide in human plasma. Sample preparation involved liquid-liquid extraction with diethyl ether-dichloromethane (60:40, v/v). The analytes and internal standard, probenecid, were separated on a Venusil XBP-C(8) column using gradient elution with acetonitrile-10 mM ammonium acetate-formic acid at a flow rate of 1.2 mL/min. Detection was by electrospray negative ionization mass spectrometry using multiple reaction monitoring of the transitions at m/z 513.0-->469.4 for telmisartan, m/z 295.9-->268.9 for hydrochlorothiazide and m/z 283.9-->239.9 for probenecid. For both analytes, the method was linear in the range 1.00-600 ng/mL with intra- and inter-day precision (as relative standard deviation) 相似文献   

LC-MS/MS测定人血浆中格列齐特的含量

目的建立液相色谱串联三重四级杆质谱(LC-MS/MS)测定人血浆中格列齐特含量的方法。方法采用ZORBAX Eclipse XDB-C 18色谱柱(50mm×2.1mm,3.5μm),流动相为乙腈-0.5%甲酸水溶液=96∶4(v/v),流速0.3mL·min^-1,柱温25℃,进样量10μL;采用电喷雾离子源,温度设为150℃电喷,正离子模式,去溶剂化温度350℃子模,扫描方式为多离子反应监控,去簇电压均为20V;碰撞能量分别为35eV(格列齐特)和20eV(格列吡嗪);用于定量分析的离子反应分别为m/z 324.0→m/z 127.0(格列齐特)和m/z 446.1→m/z 286.3(格列吡嗪),扫描时间为250ms。结果格列齐特在2~100ng·mL^-1范围内具有良好的线性关系(R^2=0.9995),定量下限为1.0ng·mL^-1,提取回收率为72.4%~77.2%(批内RSD<6.2%,批间RSD<13.6%,n=12),加样回收率为97.0%、97.5%及103.8%(n=6)。结论此方法能简单、快速、准确、灵敏地检测人血浆中格列齐特的含量,为该药药代动力学及临床研究提供方法学支持。     

Quantification of tulobuterol,a selective β2 adrenergic agonist,in human plasma by liquid chromatography-tandem quadrupole mass spectrometry

A simple and highly sensitive method coupled with liquid chromatography-tandem quadrupole mass spectrometry (LC-MS/MS) was developed and validated for the determination of tulobuterol in human plasma. Sample was preparated by liquid-liquid extraction with i-propanol–n-hexane (5:95, v/v). Tulobuterol and tulobuterol-d9 (internal standard, IS) were separatedon a 300 Extend C₁₈ column(4.6 mm×150 mm, 5 µm), using 0.1%formic acid (A)–acetonitrile (B) (30:70, v/v) as the mobile phase at the flow rate of 1.0 mL/min with an approximately 1:1 split entering the mass spectrometer. Detection was performed by positive electrospray ionization mass spectrometry multiple reaction monitoring of the precursor-to-product ion transition of tulobuterol at m/z 228.1→m/z 154.0 and tulobuterol-d9 atm/z 237.2→m/z 154.0. The assay was linear over the range 0.01–5.0 ng/mLwith a lower limit of quantitation of 0.01 ng/mL. The intra- and inter-day precisions were 3.7% and 11.1%, respectively. Recoverywas approximately 66%, and matrix effects were minimal. This method also showed satisfactory sensitivity, specificity, and carryover. The method was successfully applied to a pharmacokinetic study of tulobuterol in healthy volunteers who were given the tulobuterol patch containing 2 mg tulobuterol.     

LC-MS/MS法分析人血浆中西格列汀浓度及其应用研究

摘要：目的 建立一种测定人血浆中西格列汀浓度的液相色谱-串联质谱（LC-MS/MS）分析方法,并将该方法应 用于西格列汀在人体内的药代动力学研究。方法 以西格列汀-d4为内标,血浆样品经CleanertPPT沉淀板沉淀后, 通过Diamonsil C18色谱柱（100 mm×4.6 mm,5 μm）进行分离,使用甲醇-10 mmol/L甲酸铵水溶液（含10%甲醇,0.1% 甲酸）作为流动相,进行梯度洗脱,流速为0.5 mL/min。通过电喷雾电离源（ESI）,以多反应监测（MRM）模式进行正离 子检测。从选择性、残留、线性范围与定量下限、精密度与准确度、基质效应和回收率、稳定性方面进行方法学验证。 同时考察健康人口服西格列汀片100 mg后的主要药代动力学参数。结果 西格列汀、西格列汀-d4的MRM离子对 分别为 m/z 408.0→235.2、m/z 412.1→239.0。人血浆中西格列汀在 0.5～1 000 μg/L 浓度范围内线性关系良好（R2> 0.99）,定量下限为0.5 μg/L;定量下限和质控样品的批内、批间精密度（RSD）在0.83%~12.80%之间,准确度（RE）在± 10.0%以内。健康人口服西格列汀片100 mg后主要药代动力学参数：达峰时间（Tmax）、达峰浓度（Cmax）、、生物利用度 （AUC）、半衰期（T1/2）分别为（2.44±1.29）h、（375±138）μg/L、（2 915±585）h·μg/L、（11.10±2.41）h。结论 本LC-MS/ MS分析方法敏感度高且样品处理方法简单快速,满足生物分析的法规要求,可应用于人体内西格列汀的药代动力学 研究。     

Development of chiral liquid chromatography-tandem mass spectrometry isotope dilution methods for the determination of unconjugated and total S-equol in human plasma and urine

Liquid chromatography-tandem mass spectrometry (LC-MS/MS) methods for the determination of unconjugated and total (conjugated plus unconjugated) S-equol in human plasma and urine were developed and validated. The separation of R and S enantiomers was achieved with a Chiracel OJ-H column operated in a normal phase mode using ethanol/hexane mobile phase components. Ionization of S-equol by negative ion electrospray generated the [M-H](-) ion whose response was augmented by post-column addition of ammonium hydroxide. A triple stage quadrupole mass spectrometer was used to measure the ion current generated from the dissociative transitions m/z 241→m/z 121 (S-equol) and m/z 245→m/z 123 (equol-d(4)). The determination of total S-equol included an additional deconjugation step involving incubation of the sample with sulfatase and glucuronidase. Average recovery for both unconjugated and total S-equol was 85% with no observable matrix effects. Linearity was established for unconjugated S-equol from 0.025ng/mL to 10ng/mL (plasma) and 0.20ng/mL to 200ng/mL (urine). The average coefficient of variation and accuracy per occasion was within ±15% of the theoretical concentration of S-equol. The method was used to measure the pharmacokinetics of S-equol in human plasma after an oral administration of a single 20mg dose of S-equol to three normal healthy volunteers.     

A simple and sensitive gradient elution liquid chromatography with tandem mass spectrometry (LC-MS/MS) method for the quantification of doxorubicin in rabbit plasma

In the present study, we developed and validated a simple and sensitive gradient elution liquid chromatography tandem mass spectrometry (LC-MS/MS) method for quantification of doxorubicin in rabbit plasma. Daunorubicin was used as an internal standard (IS). The doxorubicin and IS were extracted with ethyl acetate from plasma samples. The chromatographic separations were achieved on a C₁₈ column (2.1 mm×50 mm, 2.5 μm) configured with a C₁₈ guard column (2.1 mm×10 mm, 2.5 μm). The mobile phase of 0.1% formic acid-water solution and acetonitrile was delivered using a gradient elution program at a flow rate of 0.4 mL/min. The temperature for column was maintained at 40 ºC. The electrospray ionization (ESI) source was operated in the positive ion mode, and the quantification was conducted using multiple reaction monitoring (MRM) of the transitions m/z 544.07→396.96 and m/z 528.06→321.05 for doxorubicin and IS, respectively. The calibration curve of doxorubicin was linear (r > 0.999) within the range of 2-600 ng/mL. The lower limit of quantification was 2 ng/mL. The relative errors of intra­day and inter-day accuracies ranged from -2.48% to 0.18% and from -3.78% to 1.94%, respectively. The relative standard deviations of intra­day and inter-day precisions were less than 8.65% and 6.41%, respectively. The method exhibited satisfactory results in terms of specificity, sensitivity, matrix effect, recovery and stability. The newly developed LC-MS/MS method was reliable to monitor doxorubicin concentrations in rabbit plasma.     

LC-MS/MS 法测定人血浆中倍他米松

建立测定人血浆中倍他米松的LC-MS/MS方法。采用Venusil XBP C₈ (200 mm×3.9 mm ID, 5 μm)色谱柱，流动相为甲醇-水(含甲酸铵5 mmol·L^-1)(80∶20)，流速0.4 mL·min^-1；质谱仪离子源为电喷雾离子源(ESI)，正离子模式检测，监测离子为393.3→355.2(倍他米松)和361.3→343.2(泼尼松龙,内标)。血浆样本用乙酸乙酯处理。倍他米松在0.5~80.0 ng·mL^-1线性关系良好(r=0.999 2)， 血浆低、 中、 高3种浓度(1.0， 10.0， 60.0 ng·mL^-1)平均提取回收率为88.24%，定量限为0.5 ng·mL^-1。本方法操作简便、准确、灵敏，适用于复方倍他米松注射液人体药代动力学研究。     

LC-MS/MS法测定人血浆中加巴喷丁的浓度及其药动学研究

建立液相色谱串联质谱(LC-MS/MS)法测定人血浆中加巴喷丁的浓度并将其应用于人体药动学研究。取血浆样品经甲醇沉淀蛋白后,以甲醇0.2%甲酸水溶液(80∶20)为流动相,用Inertsil ODS-3 C18柱(50 mm×2.1 mm ID,3μm)分离,采用电喷雾离子源,以多反应监测(MRM)方式进行正离子检测,定量分析的离子反应分别为m/z 172→m/z 154(加巴喷丁)和m/z 130→m/z 71(内标二甲双胍)。加巴喷丁线性范围为40.8～8.16×103 ng.mL 1,定量限为40.8 ng.mL 1,每个样品测试时间仅2.2 min,日内、日间精密度(RSD)均小于12%,准确度(RE)在±6.4%范围内。应用此法研究了20名健康志愿者单剂量口服加巴喷丁胶囊600 mg后的药动学特点。该方法快速、专属、灵敏、适用性强,可应用于加巴喷丁的人体药动学研究。