Simultaneous quantification of methylene blue and its major metabolite,azure B,in plasma by LC‐MS/MS and its application for a pharmacokinetic study

A simple and sensitive liquid chromatography‐tandem mass spectrometry (LC‐MS/MS) method was developed for the quantification of methylene blue (MB) and its major metabolite, azure B (AZB), in rat plasma. A simple protein precipitation using acetonitrile was followed by injection of the supernatant on to a Zorbax HILIC Plus column (3.5 µm, 2.1 × 100 mm) with isocratic mobile phase consisting of 5 mM ammonium acetate in 10:90 (v/v) water:methanol at a flow rate of 0.3 mL/min and detection in positive ionization mode. The standard curve was linear over the concentration range from 1 to 1000 ng/mL for MB and AZB with coefficient of determination above 0.9930. The lower limit of quantification was 1 ng/mL using 20 μL of rat plasma sample. The intra‐ and inter‐assay precision and accuracy were <12%. The developed analytical method was successfully applied to the pharmacokinetic study of MB and AZB in rats. Copyright © 2013 John Wiley & Sons, Ltd.     

Determination of gabapentin in human plasma using hydrophilic interaction liquid chromatography with tandem mass spectrometry

A rapid, sensitive and selective method for the determination of gabapentin in human plasma was developed using hydrophilic interaction liquid chromatography/tandem mass spectrometry (HILIC/MS/MS). The devised method involved protein precipitation with acetonitrile followed by separation on an Atlantis HILIC silica column using an acetonitrile/ammonium formate mobile phase (100 mM, pH 3.0) (85:15, v/v). Analytes were detected using an electrospray ionization mass spectrometer in the multiple-reaction monitoring mode. The standard curve was linear (r = 1.000) over the concentration range of 50.0-10000 ng/mL. The lower limit of quantification for gabapentin was 50.0 ng/mL (ca. 20 pg gabapentin) using a 10-microL plasma sample. The coefficients of variation and relative errors for intra- and inter-assay at four QC levels (i.e., 50.0, 125, 750, and 7500 ng/mL) were 4.7 to 9.4% and -4.1 to 1.6%, respectively. Absolute and relative matrix effects for gabapentin and metformin were practically absent. Gabapentin and metformin recoveries were 98.5% and 99.0%, respectively. This method was successfully applied to a bioequivalence study of gabapentin in humans.     

亲水作用色谱法测定胡芦巴中的胡芦巴碱

建立了亲水作用色谱法(HILIC)测定胡芦巴药材中胡芦巴碱含量的方法。采用Waters Atlantis HILIC Silica色谱柱(150 mm×2.1 mm, 3 μm),以乙腈-乙酸铵溶液(pH 4.4)(体积比为70:30)为流动相,流速0.4 mL/min,检测波长265 nm。胡芦巴碱的线性范围为2.50～100 mg/L (r=0.9996);两个加标水平的平均加样回收率为102%,相对标准偏差(RSD)分别为4.17%和2.28%(n=3)。结果表明所建方法分离效果好、快速简易,可以弥补中国药典中离子对色谱法(IPLC)平衡时间过长的缺陷,适用于胡芦巴药材中强极性胡芦巴碱的测定,为胡芦巴的质量控制提供了有效的方法。     

LC‐ESI‐MS/MS analysis of quercetin in rat plasma after oral administration of biodegradable nanoparticles

A simple, rapid and sensitive LC‐MS/MS method was developed and validated for the determination of free quercetin in rat plasma, using fisetin as internal standard. The detection was performed by negative ion electrospray ionization under selected reaction monitoring. Chromatographic separation (isocratic elution) was carried out using acetonitrile–10 m m ammonium formate (80:20, v/v) with 0.1% v/v formic acid. The lower limit of quantification (4.928 ng/mL) provided high sensitivity for the detection of quercetin in rat plasma. The linearity range was from 5 to 2000 ng/mL. Intra‐ and inter‐day variability (RSD) of quercetin extraction from rat plasma was <4.19 and 1.37% with accuracies of 98.77 and 99.67%. The method developed was successfully applied for estimating free quercetin in rat plasma, after oral administration of quercetin‐loaded biodegradable nanoparticles (QLN) and quercetin suspension. QLN (C_max, 1277.34 ± 216.67 ng/mL; AUC, 17,458.25 ± 3152.95 ng hr/mL) showed a 5.38‐fold increase in relative bioavailability as compared with quercetin suspension (C_max, 369.2 ± 108.07 ng/mL; AUC, 3276.92 ± 396.67 ng hr/mL). Copyright © 2015 John Wiley & Sons, Ltd.     

Simultaneous determination of sibutramine and its active metabolites in human plasma by LC‐MS/MS and its application to a pharmacokinetic study

A simple and sensitive liquid chromatography–electrospray ionization–tandem mass spectrometry (LC‐ESI‐MS/MS) technique was developed and validated for the determination of sibutramine and its N‐desmethyl metabolites (M1 and M2) in human plasma. After extraction with methyl t‐butyl ether, chromatographic separation of analytes in human plasma was performed using a reverse‐phase Luna C₁₈ column with a mobile phase of acetonitrile–10 mm ammonium formate buffer (50:50, v/v) and quantified by ESI‐MS/MS detection in positive ion mode. The flow rate of the mobile phase was 200 μL/min and the retention times of sibutramine, M1, M2 and internal standard (chlorpheniramine) were 1.5, 1.4, 1.3 and 0.9 min, respectively. The calibration curves were linear over the range 0.05–20 ng/mL, for sibutramine, M1 and M2. The lower limit of quantification was 0.05 ng/mL using 500 μL of human plasma. The mean accuracy and the precision in the intra‐ and inter‐day validation for sibutramine, M1 and M2 were acceptable. This LC‐MS/MS method showed improved sensitivity and a short run time for the quantification of sibutramine and its two active metabolites in plasma. The validated method was successfully applied to a pharmacokinetic study in human. Copyright © 2011 John Wiley & Sons, Ltd.     

Determination of pethidine in human plasma by LC–MS/MS

A sensitive and selective liquid chromatography–tandem mass spectrometry method for the determination of pethidine in human plasma was developed and validated over the concentration range of 4–2000 ng/mL. After addition of ketamine as internal standard, liquid–liquid extraction was used to produce a protein‐free extract. Chromatographic separation was achieved on a 100 × 2.1 mm, 5 µm particle, Allure^TM PFP propyl column, with 45:40:15 (v/v/v) acetonitrile–methanol–water containing 0.2% formic acid as mobile phase. The MS data acquisition was accomplished by multiple reactions monitoring mode with positive electrospray ionization interface. The lower limit of quantification was 4 ng/mL; for inter‐day and intra‐day tests, the precision (RSD) for the entire validation was less than 7%, and the accuracy was within 95.9–106.5%. The method is sensitive and simple, and was successfully applied to analysis of samples of clinical intoxication. Copyright © 2010 John Wiley & Sons, Ltd.     

Simultaneous determination of nalbuphine and its prodrug sebacoly dinalbuphine ester in human plasma by ultra‐performance liquid chromatography–tandem mass spectrometry and its application to pharmacokinetic study in humans

A rapid, simple, sensitive and selective ultraperformance liquid chromatography–tandem spectrometry (UPLC‐MS/MS) method for the determination of nalbuphine and its prodrug sebacoly dinalbuphine ester (SDE) was developed and validated in human plasma. The sample pretreatment involves basification and iterative liquid–liquid extraction with ethyl‐ether–dichloromethane (7:3, v/v) solution, followed by LC separation and positive electrospray ionization (ESI) API‐3000 mass spectrometry detection. The chromatography was on a Waters Acquity UPLC BEH HILIC column (2.1 × 100 mm, 1.7 µm). The mobile phase was composed of acetonitrile and water (83:17, v/v) that contained 0.2% formic acid and 4 mm ammonium formate at a flow rate of 0.25 mL/min. Ethylmorphine and naloxine were selected as the SDE and nalbuphine internal standard (IS), respectively. The calibration curve for both was linear over the range from 0.05 to 20 ng/mL, with correlation coefficients ≥0.995. The lower limit of quantification was set at 0.05 ng/mL. The intra‐ and inter‐day precision values for nalbuphine and SDE were acceptable as per FDA guidelines. The method was applied successfully to determine nalbuphine concentration in human plasma samples obtained from four Taiwanese volunteers receiving intramuscularly administration of sebacoyl dinalbuphine ester. The method is sensitive, selective and directly applicable to human pharmacokinetic studies involving nalbuphine. Copyright © 2013 John Wiley & Sons, Ltd.     

High-performance liquid chromatography of lactose with evaporative light scattering detection, applied to determine fine particle dose of carrier in dry powder inhalation products

A method for quantification of the fine particle dose of lactose is described, using a hydrophilic interaction chromatography (HILIC) method and evaporative light scattering detection. The HILIC method used an aminopropyl column and a mobile phase consisting of acetonitril/water (80/20, v/v) for isocratic elution. Sensitive chromatography was obtained using a low concentration of water in the extraction solvent. The detection limit (RSD<10%) at an injection volume of 10 microL is 10 microg/mL. Linearity was obtained in the range of 10-80 microg/mL (R(2)>0.99). A relative standard deviation (RSD) of 0.5% (N=6) demonstrated good precision of the optimized method.     

Highly sensitive determination of Schisandrin and Schisandrin B in plasma of rats after administration of Wurenchun (Fructus Schisandrae Chinensis Extracts) preparations by LC‐ESI‐MS/MS

A sensitive and specific method based on liquid chromatography‐tandem mass spectrometry using electrospray ionization (LC‐ESI‐MS/MS) has been developed for the determination of Schisandrin and Schisandrin B in rat plasma. A 100 μL plasma sample was extracted by methyl tert‐butyl ether after spiking the samples with nimodipine (internal standard) and performed on an XTerra®MS‐C₁₈ column (150 mm × 2.1 mm, 3.5 μm) with the mobile phase of acetonitrile–water–formic acid (80:20:0.2, v/v) at a flow rate of 0.2 mL/min in a run time of 8.5 min. The lower limit of quantification of the method was 40 ng/mL for Schisandrin and 20 ng/mL for Schisandrin B. The method showed reproducibility with intra‐day and inter‐day precision of less than 13.8% RSD, as well as accuracy, with inter‐ and intra‐assay accuracies between 93.5 and 107.2%. Finally, the LC‐ESI‐MS/MS method was successfully applied to study the pharmacokinetics of Schisandrin and Schisandrin B in rats after administration of Wurenchun commercial formulations to rats. Copyright © 2009 John Wiley & Sons, Ltd.     

Development and validation of UPLC‐MS/MS method for determination of domperidone in human plasma and its pharmacokinetic application

A sensitive, rapid and selective ultra‐performance liquid chromatography–tandem mass spectrometric (UPLC‐MS/MS) method was developed for the determination and pharmacokinetic study of domperidone in human plasma. Diphenhydramine was used as the internal standard. Plasma sample pretreatment involved a one‐step liquid–liquid extraction with a mixture of diethyl ether–dichloromethane (3:2, v/v). The analysis was carried out on an Acquity UPLC^TM BEH C₁₈ column. The mobile phase consisted of methanol–water containing 10 mmol/L ammonium acetate and 0.5% (v/v) formic acid (60:40, v/v). The detection was performed on a triple quadrupole tandem mass spectrometer in multiple reaction monitoring mode via electrospray ionizationsource with positive mode. Each plasma sample was chromatographed within 2.1 min. The standard curves for domperidone were linear (r² ≥ 0.99) over the concentration range of 0.030–31.5 ng/mL with a lower limit of quantification of 0.030 ng/mL. The intra‐ and inter‐day precision (relative standard deviation) values were not higher than 13% and accuracy (relative error) was from ?7.6 to 1.2% at three quality control levels. The method herein described was superior to previous methods and was successfully applied to the pharmacokinetic study of domperidone in healthy Chinese volunteers after oral administration. Copyright © 2012 John Wiley & Sons, Ltd.     

超高效液相色谱-大气压化学电离-串联质谱法测定烘焙咖啡中丙烯酰胺

建立了烘焙咖啡中丙烯酰胺的超高效液相色谱-大气压化学电离-串联质谱（UHPLC-APCI-MS/MS）分析方法。样品经甲醇提取，HLB固相萃取（SPE）小柱净化，Brownlee validated AQ C18色谱柱分离，采用大气压化学电离（APCI）源，正离子扫描和多反应监测（MRM）模式对丙烯酰胺进行检测，内标法定量。结果表明，丙烯酰胺在0.5~100.0 μg/L范围内具有良好的线性关系，相关系数（r²）为0.999，方法检出限为5.0 μg/kg，定量限为10.0 μg/kg。在100.0、200.0和1000.0 μg/kg添加水平下，丙烯酰胺的回收率为94.6%~115.0%，相对标准偏差（RSD）值为2.8%~3.6%（n=6）。本方法采用APCI源作为离子化方式，能有效地减少咖啡基质对丙烯酰胺的基质干扰，前处理简单，灵敏度高，适用于咖啡中丙烯酰胺的日常检测。     

An LC–MS/MS method for rapid and sensitive high‐throughput simultaneous determination of various protein kinase inhibitors in human plasma

A reliable, high‐throughput and sensitive LC–MS/MS procedure was developed and validated for the determination of five tyrosine kinase inhibitors in human plasma. Following their extraction from human plasma, samples were eluted on a RP Luna®‐PFP 100 Å column using a mobile phase system composed of acetonitrile and 0.01 m ammonium formate in water (pH ~4.1) with a ratio of (50:50, v /v) flowing at 0.3 mL min⁻¹. The mass spectrometer was operating with electrospray ionization in the positive ion multiple reaction monitoring mode. The proposed methodology resulted in linear calibration plots with correlation coefficients values of r ² = 0.9995–0.9999 from concentration ranges of 2.5–100 ng mL⁻¹ for imatinib, 5.0–100 ng mL⁻¹ for sorafenib, tofacitinib and afatinib, and 1.0–100 ng mL⁻¹ for cabozantinib. The procedure was validated in terms of its specificity, limit of detection (0.32–1.71 ng mL⁻¹), lower limit of quantification (0.97–5.07 ng mL⁻¹), intra‐ and inter assay accuracy (−3.83 to +2.40%) and precision (<3.37%), matrix effect and recovery and stability. Our results demonstrated that the proposed method is highly reliable for routine quantification of the investigated tyrosine kinase inhibitors in human plasma and can be efficiently applied in the rapid and sensitive analysis of their clinical samples.     

Determination of caudatin-2,6-dideoxy-3-O-methy-beta-d-cymaropyranoside in rat plasma using liquid chromatography-tandem mass spectrometry

A selective, sensitive and rapid liquid chromatography-tandem mass spectrometry method has been developed for the determination of caudatin-2,6-dideoxy-3-O-methy-beta-d-cymaropyranoside (CDMC) in rat plasma. This method involves a plasma clean-up step using liquid-liquid extraction, followed by LC separation and positive electrospray ionization mass spectrometry detection (LC/ESI-MS/MS). Chromatographic separation of the analytes was achieved using a C(18) column with a mobile phase of acetonitrile and water (70:30, v/v) at a flow rate of 1.0 mL/min. Low energy collision tandem mass spectrometric analysis (CID-MS/MS) using the multiple reaction monitoring (MRM) mode was used for analyte quantification. For the MRM analysis of CDMC, the following transition at m/z 658.4 --> 529.6 derived from the protonated molecule [M + Na](+). A calibration curve was linear in the 5-500 ng/mL range for CDMC, and the limit of detection was 5 ng/mL. The inter- and intra-day precisions (RSD) were 相似文献   

An LC‐MS/MS method for the simultaneous determination and pharmacokinetic studies of bergenin,chlorogenic acid and four flavonoids in rat plasma after oral administration of a QingGanSanJie decotion extract

A rapid, simple and sensitive, liquid chromatography–tandem mass spectrometry (LC‐MS/MS) method was developed and validated for simultaneous determination of bergenin, chlorogenic acid and four flavonoids in a QingGanSanJie preparation in rat plasma. Puerarin was selected as the internal standard (IS). Plasma samples were precipitated with methanol and separated with a reverse phase Agilent Poroshell 120 EC‐C₁₈ column using a gradient mobile phase of methanol–water containing 0.1% formic acid (v/v). A triple quadruple mass spectrometer was used for quantification (limit of detection 0.36–5.55 ng/mL). Intra‐day and inter‐day precisions were within 15% and the average extraction recoveries ranged from 85 to 115% for each analyte. The method allowed simultaneous quantification for the first time of the pharmacokinetics of bergenin, chlorogenic acid and four flavonoids after intragastric administration of a QingGanSanJie extract in Sprague–Dawley rats. It was found that bergenin and chlorogenic acid had typical extravascular administration concentration–time curves; flavonoids had a bimodal distribution improving bioavailability and extending the pharmacodynamics period. Copyright © 2014 John Wiley & Sons, Ltd.     

Determination of lovastatin in human plasma by ultra-performance liquid chromatography/electrospray ionization tandem mass spectrometry

A fast and sensitive ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) method was developed for the determination of lovastatin in human plasma. With simvastatin as internal standard, sample pretreatment involved one-step extraction with n-hexane-methylene dichloride-isopropanol (20:10:1, v/v/v) of 0.5 mL plasma. Chromatographic separation was carried out on an Acquity UPLC BEH C(18) column with mobile phase consisting of acetonitrile-water (containing 5 mmol/L ammonium acetate; 85:15, v/v) at a flow-rate of 0.35 mL/min. The detection was performed on a triple-quadrupole tandem mass spectrometer by multiple reaction monitoring (MRM) via electrospray ionization source with positive mode. The analysis time was shorter than 1.7 min per sample. The standard curve was linear (r2>or=0.99) over the concentration range 0.025-50.0 ng/mL with a lower limit of quantification of 0.025 ng/mL. The intra- and inter-day precision values were below 11% and the accuracy (relative error) was within 6.0% at three quality control levels. This is the first method of MS with MRM coupled to UPLC for the determination of lovastatin, which showed great advantages of high sensitivity, selectivity and high sample throughput. It was fully validated and successfully applied to the pharmacokinetic study of lovastatin tablets in healthy Chinese male volunteers after oral administration.     

Hydrophilic interaction chromatography‐tandem mass spectrometric analysis of irbesartan in human plasma: Application to pharmacokinetic study of irbesartan

A hydrophilic interaction chromatography‐tandem mass spectrometric method (HILIC/MS/MS) for the determination of irbesartan in human plasma was developed. Irbesartan and losartan (internal standard) were extracted from human plasma with ethyl acetate at acidic pH. The analytes were analyzed on a Luna HILIC column with the mobile phase of ACN–ammonium formate (50 mM, pH 6.5) (96:4, v/v) and detected by ESI MS/MS in the selected reaction monitoring mode. The standard curve was linear (r² = 0.9981) over the concentration range of 10–2500 ng/mL and the lower LOQ was 10 ng/mL using 100 μL of plasma sample. The CV and relative error for intra‐ and interassay at four QC levels were 2.9 to 8.1% and –2.7 to 2.3%, respectively. There were less absolute and relative matrix effects for irbesartan and losartan. The present method was successfully applied to the pharmacokinetic study of irbesartan after oral dose of irbesartan (150 mg tablet) to male healthy volunteers.     

Electrochemical Determination of Synephrine by Hydrophilic Interaction Liquid Chromatography Using a Zwitterionic Monolith Column

A sensitive method for the electrochemical determination of synephrine (SYN) by hydrophilic interaction liquid chromatography (HILIC) has been developed. Optimal chromatographic separation and high sensitive determination by HILIC with electrochemical detection (HILIC‐ECD) was achieved using a sulfobetaine‐type zwitterionic monolith column (100×1.02 mm, i.d.), a mixture of 10 mM sodium phosphate (pH 4) and acetonitrile (20 : 80, v/v) as mobile phase, and a glassy carbon working electrode which was applied with a potential at +1.0 V vs. Ag/AgCl. The chromatographic peak height of SYN was proportional to the concentration from 5.0 µg/L to 1.0 mg/L (r=0.999). The detection limit of SYN (S/N=3) was 3.7 pg on the column. Moreover, the present HILIC‐ECD could be applied to the accurate and precise determination of SYN in Aurantii nobilis Pericarpium. In conclusion, we have demonstrated that an ECD is one of useful detection methods applicable to HILIC.     

A novel UPLC‐MS/MS method for sensitive quantitation of boldine in plasma,a potential anti‐inflammatory agent: application to a pharmacokinetic study in rats

Boldine is a potential anti‐inflammatory agent found in several different plants. Published bioanalytical methods using HPLC with ultraviolet and fluorescent detection lacked enough sensitivity and required tedious sample preparation procedures. Herein, we describe the development of a novel ultra‐high performance LC with MS/MS for determination of boldine in plasma. Boldine in plasma was recovered by liquid–liquid extraction using 1 mL of methyl tert‐butyl ether. Chromatographic separation was performed on a C₁₈ column at 45°C, with a gradient elution consisting of acetonitrile and water containing 0.1% (v/v) formic acid at a flow rate of 0.3 mL/min. The detection was performed on an electrospray triple‐quadrupole MS/MS by positive ion multiple reaction monitoring mode. Good linearity (r² > 0.9926) was achieved in a concentration range of 2.555–2555 ng/mL with a lower limit of quantification of 2.555 ng/mL for boldine. The intra‐ and inter‐day precisions of the assay were 1.2–6.0 and 1.8–7.4% relative standard deviation with an accuracy of ?6.0–8.0% relative error. This newly developed method was successfully applied to a single low‐dose pharmacokinetic study in rats and was demonstrated to be simpler and more sensitive than the published methods, allowing boldine quantification in reduced plasma volume. Copyright © 2014 John Wiley & Sons, Ltd.     

液相色谱-串联质谱分析组织中基因组脱氧核糖核酸羟甲基胞嘧啶水平

5-羟甲基胞嘧啶通过阻止脱氧核糖核酸(DNA)甲基化转移酶1(DMNT1)甲基化胞嘧啶来影响DNA甲基化的程度。本文建立了液相色谱-串联质谱(LC-MS/MS)测定组织中全基因组5-羟甲基胞嘧啶水平的方法。采用苯酚-氯仿提取组织DNA,提取的DNA用88%甲酸在140 ℃下裂解,DNA裂解液加入同位素胞嘧啶作内标,经N2吹干后,加乙腈-水(9:1, v/v)溶解,用LC-MS/MS检测5-羟甲基胞嘧啶的含量,并计算全基因组中5-羟甲基胞嘧啶的水平。结果表明,5-羟甲基胞嘧啶的线性范围为0.1～30 ng/mL,相关系数为0.9969,检出限(信噪比为3计)和定量限(信噪比为10计)分别为0.057 ng/mL和0.090 ng/mL;日内相对标准偏差和日间相对标准偏差分别为5.13%和6.24%;加标回收率为90.24%～97.53%。用该方法检测了大鼠大脑组织DNA羟甲基化水平,平均结果为0.66%。该方法简便,重现性好,灵敏度较高,能满足全基因组5-羟甲基胞嘧啶定量检测的要求。     

Rapid quantification of lisinopril in human plasma by liquid chromatography/tandem mass spectrometry

An assay based on protein precipitation and liquid chromatography/tandem mass spectrometry (LC-MS/MS) has been developed and validated for the quantitative analysis of lisinopril in human plasma. After the addition of enalaprilat as internal standard (IS), plasma samples were prepared by one-step protein precipitation using perchloric acid followed by an isocratic elution with 10 mm ammonium acetate buffer (pH adjusted to 5.0 with acetic acid)-methanol (70:30, v/v) on a Phenomenex Luna 5 mu C(18) (2) column. Detection was performed on a triple-quadrupole mass spectrometer utilizing an electrospray ionization (ESI) interface operating in positive ion and selected reaction monitoring (SRM) mode with the precursor to product ion transitions m/z 406 --> 246 for lisinopril and m/z 349 --> 206 for enalaprilat. Calibration curves of lisinopril in human plasma were linear (r = 0.9973-0.9998) over the concentration range 2-200 ng/mL with acceptable accuracy and precision. The limit of detection and lower limit of quantification in human plasma were 1 and 2 ng/mL, respectively. The validated LC-MS/MS method has been successfully applied to a preliminary pharmacokinetic study of lisinopril in Chinese healthy male volunteers.