LC-ESI-MS method for the determination of bisoprolol in human plasma

A sensitive liquid chromatography-electrospray ionization-mass spectrometry (LC-ESI-MS) method has been developed and validated for the determination of bisoprolol in human plasma, using metoprolol as internal standard (I.S.). After alkalization with sodium hydroxide, the samples were extracted with ethyl acetate and separated by HPLC on a ZORBAX SB-C18 column with a mobile phase of 10 mM ammonium acetate buffer containing 0.1% formic acid-methanol (32:68, v/v) at a flow rate of 1 ml/min. The chromatographic separation was achieved in less than 5 min. The linearity was established over the concentration range of 0.05-120 ng/ml. The intra- and inter-run standard deviation was less than 3.8 and 7.5%, respectively. The method had been successfully applied to study the relative bioavailability of bisoprolol fumarate tablets in healthy Chinese volunteers. The pharmacokinetic parameters of the reference and test tablets have been compared.     

Sensitive and rapid LC-ESI-MS method for the determination of trimetazidine in human plasma

A sensitive method, based on liquid chromatography-electrospray ionisation-mass spectrometry (LC-ESI-MS), was developed for the determination of trimetazidine in human plasma. Buflomedil was used as the internal standard (IS). Plasma samples were extracted with a mixture of cyclohexane-diethyl ether (1:1, v/v) and the analytes were chromatographically separated on a phenomenex Luna 5 mu C18 (2) 100A HPLC column with a mobile phase of 10 mM ammonium acetate buffer solution containing 0.1% acetic acid-methanol (45:55, v/v). The electrospray ionization was employed in a single quadrupole mass spectrometer for the analytical determination. The lower limit of quantification (LLOQ) was 0.5 ng/ml for trimetazidine and the measuring ranges were from 0.5 to 200 ng/ml. The intra- and inter-run standard deviation was less than 4.1% and 7.8%, respectively. The method was successfully applied to study the pharmacokinetics of trimetazidine in healthy Chinese volunteers.     

Development of a LC-ESI-MS3 method for determination of nitrendipine in human plasma

A novel and sensitive method utilizing high performance liquid chromatography coupled with electrospray ionization source tandem mass spectrometry (LC-ESI-MS³) was developed for the first time in order to analyze nitrendipine in human plasma samples. Human plasma samples were prepared by protein precipitation with acetonitrile and well resolved on a 100 mm reversed-phase column in gradient elution with 0.05% (v/v) formic acid in acetonitrile as the mobile phase. Determination was performed in MS³ scan mode for nitrendipine and in the multiple reaction monitoring (MRM) mode for nimodipine (internal standard). This method, having a lower limit of quantification (LLOQ) of 0.05 ng/mL when using a 100 μL sample aliquot (5 pg/sample), is acceptable for calibration of the linearity and repeatability and is of better sensitivity than the reported methods (>0.25 ng/mL). The major advantages of the method are that small sample volume (100 μL) is required, simple sample processing technique, high sensitivity and excellent selectivity is guaranteed by the MS³ detection. The proposed validated method has been successfully applied to a clinical study on nitrendipine.     

简单灵敏的高效液相色谱法测定人血浆中去甲万古霉素的浓度

目的建立血浆中去甲万古霉素含量的HPLC测定方法。方法采用高效液相色谱检测法,分析柱为Tskgel ODS-80TS（4．6mm×250mm,5μm）,流动相为10mmol·L^-1甲酸铵（0．1％甲酸）-甲醇（0．1％甲酸）=（82：18,v／v）,流速：1．0mL·min^-1,柱温：30℃,检测波长：236nm,进样量：20μL.血浆样品用三氟醋酸直接沉淀后,进样分析。结果去甲万古霉素在1～1000μg·mL^-1与峰面积线性关系良好（r=0．999）,最低检测浓度为1μg·mL^-1。平均回收率为96％;日间、日内RSD均〈15％。结论研究建立的HPLC法快速、简便、高效,精密度和准确度高,适合血样中去甲万古霉素浓度的检测。     

简单灵敏的HPLC法测定人血浆中头孢丙烯浓度

目的:建立血浆中头孢丙烯的HPLC检测方法.方法:采用高效液相色谱检测法,分析柱为Hypersil BDS C18 (200 mm×4.6 mm,5μm),流动相为20 mmol/L乙酸铵/10％乙酸(pH=3.7):乙腈=92:8(V/V),流速1.0 mL/min,柱温30℃,检测波长282 nm,进样量20μL.血浆样品用三氟醋酸直接沉淀后,取上清进样分析.结果:头孢丙烯在0.10～10.01 μg/mL范围内线性关系良好(r=1.0000),最低定量浓度为0.10μg/mL,日内日间RSD均＜15％(n=15).结论:研究建立的HPLC法快速、简便、高效,精密度和准确度高,适合血样中头孢丙烯浓度的检测.     

A sensitive method for the determination of gemfibrozil in human plasma samples by RP-LC.

A sensitive high-performance liquid chromatographic assay for the quantitative determination of gemfibrozil is described in this work. Ibuprofen was used as internal standard. The assay involved a single cyclohexane extraction and LC analysis with fluorescence detection. Chromatography was performed at 40 degrees C on a Hypersil ODS column. The mobile phase was a mixture of a solution of phosphoric acid 0.4% and acetonitrile (45:55). The method was validated. The detection limit of this method was 0.025 microg ml(-1); only 0.5 ml of the plasma sample was required for the determination. The calibration graph was linear from 0.05 to 0.5 microg ml(-1) and required a cubic equation from 0.5 to 30 microg ml(-1). Intra and inter-day precision (C.V.) did no exceed 15%. Mean recoveries were of 90.15+/-6.9% (C.V.'s<8%) for gemfibrozil and 93.10% for ibuprofen Applicability of the method was demonstrated by a pharmacokinetic study in normal volunteers who received gemfibrozil by oral route.     

A sensitive liquid chromatography and mass spectrometry method for the determination of posaconazole in human plasma

Posaconazole is a novel extended-spectrum triazole that has favorable in vitro, in vivo and clinical activity against a number of yeasts and moulds. Posaconazole is available as an oral suspension. The dosage found to result in monitored plasma levels that correlate with clinical evidence of good antifungal activity is 800 mg/day in divided doses. A liquid chromatographic/mass spectrometric method (LC-MS/MS) that can be used by clinicians wishing to quantitate, and thereby monitor, plasma levels of posaconazole in certain patients was validated. The method utilized semi-automated 96-well protein precipitation with gradient chromatographic separation of analytes using a Varian Polaris C-18A (2.0 mm x 50 mm, 5-microm particle size) column. The approximate retention time of posaconazole was 2.0 min. Analytes were detected by using tandem mass spectrometry. Sample introduction and ionization was performed by atmospheric pressure chemical ionization in the positive-ion mode. This method has been proven suitable for routine quantitation of posaconazole over the concentration range of 5.00-5000 ng/mL. Inter-run precision based on percent relative deviation for replicate quality controls was < or = 6.2%. Inter-run accuracy expressed as %DIFF was +/-4.0%. Posaconazole quality controls were stable in human plasma for up to five freeze-thaw cycles, when frozen at -20 degrees C for at least 105 days and when kept at room temperature for 24 h. The lower limit of quantitation was 5.00 ng/mL for a 100-microL sample aliquot. These data indicate that the LC-MS/MS method described is suitable for the rapid measurement of posaconazole over the concentration range of 5.00-5000 ng/mL.     

吲哒帕胺血药浓度测定及药动学研究

目的:建立一种测定人体血浆中吲哒帕胺血药浓度的高效液相色谱法。方法:采用 ULTRON VX-ODS 色谱柱(5μm,4.6 mm×250 mm),以甲醇-乙腈-水(50∶5∶45)为流动相,流速1 mL·min~(-1),柱温:室温,检测波长242 nm。结果:本方法线性范围为0.54～172.8ng·mL~(-1),r=0.9940,方法定量限为(0.54±0.04)ng·mL~(-1)(S/N>10),方法回收率为97.8%～108.1%(n=15),日内 RSD 为3.0%～13.4%(n:5),日间 RSD 为2.5%～14.4%(n=5).结论:本方法灵敏度高,操作简便准确,可用于人体血浆中吲哒帕胺浓度的测定及药动学研究.     

A rapid, sensitive HPLC method for the determination of ganciclovir in human plasma and serum

A method for ganciclovir determination in human serum and plasma has been developed and validated. The method has a lower limit of quantification (LLOQ) adequate for sensitive pharmacokinetic studies ( < or = 0.05 microg/ml), has run times of < or = 15 min, and uses aliquot volumes adequate for pediatric studies (0.25 ml). In the method, proteinaceous material in serum or plasma is precipitated by trichloroacetic acid. An aliquot of the supernatant is analyzed by HPLC; automated column switching removes late-eluting materials that might interfere with the analyte peak in subsequent runs. Detection and quantification of ganciclovir is by fluorescence (lambda(ex) = 278 nm; lambda(em) = 380 nm). The method has a validated range of 0.0400-4.00 microg/ml and an LLOQ of 0.0400 microg/ml. All intra- and inter-assay % C.V. values were < 8%; all recoveries (accuracy) were within 7% of nominal values. No interference was observed by mycophenolic acid or its glucuronide metabolite, by AZT, salicylic acid, acetaminophen, ibuprofen, naproxen prednisone, acyclovir, or cyclosporine. Ganciclovir is very stable in the samples and the extract during storage and sample processing. Both serum and plasma methods have been validated for use and have been successfully used to analyze samples from clinical studies.     

简单灵敏的LC-MS/MS方法检测人血浆中普伐他汀的浓度

目的:建立液质联用法测定人血浆中普伐他汀的浓度.方法:空白血浆加普伐他汀和内标,用Bond Elut C18小柱进行固相提取,然后用LC-MS/MS进行分析.采用Thermo Hypurity C18柱(150 mm×2.1mm,5 μm),流动相为乙腈-0.2%甲酸水溶液(85:15),流速0.2 mL·min-1,柱温40℃,进样量为2 μL.采用ESI正离子方式进行检测,用于定量分析的检测离子为m/z 447→327(普伐他汀钠)和m/z 482→272(瑞舒伐他汀).结果:本方法线性范围是2.52～660 μg·L-1,r2=0.994,最小检出浓度(LLOQ)为2.52 μg·L-1.绝对回收率均在70%以上,相对回收率在98%～102%之间,日内、日间RSD均<15%.结论:本方法简便、灵敏、准确,可用于普伐他汀血药浓度检测和药动学研究.     

快速灵敏的LC-MS/MS法测定人血浆中缬沙坦浓度

目的：建立一种快速、灵敏的高效液相色谱-串联质谱法（LC-MS/MS）测定人血浆缬沙坦浓度。方法：200μL血浆样品经乙腈一步沉淀蛋白后,在Inertsil ODS-色谱柱（2.1mm×150mm,5μm）上分离,流动相由乙腈和1‰甲酸水溶液（70∶30）组成。采用电喷雾离子源（ESI源）正离子多反应监测（MRM）扫描分析,缬沙坦和厄贝沙坦的离子选择通道分别为：m/z436.3→235.2和429.4→207.2。结果：缬沙坦的线性范围为24.2～3100.0μg/L,日内和日间相对标准差均小于15%。结论：本法操作快速、灵敏,适用于缬沙坦的临床药动学研究。     

A sensitive HPLC method for the determination of fluoxetine and norfluoxetine in human plasma with fluorescence detection

A selective, sensitive, and precise HPLC method for the simultaneous determination of fluoxetine (FL) and its N-demethylated metabolite norfluoxetine (NFL) in human plasma has been developed. Following extraction with n-hexane, FL, NFL, and fluvoxamine (internal standard) were derivatized with 7-chloro-4-nitrobenzofurazan (NBD-Cl) under weakly alkaline conditions. NBD derivatives were extracted with chloroform after acidification and chromatographed on a reversed-phase column with gradient elution using acetonitrile and 0.1 mol/L nitric acid (pH 3) solution. Calibration curves were linear over the range of 1.0-100.0 ng/mL and 0.1-50.0 ng/mL for FL and NFL, respectively, with inter- and intraassay precision given by a relative standard deviation (RSD%) of less than 9.2%. The lower limits of quantification were 1.0 ng/mL for FL and 0.1 ng/mL for NFL. Recoveries of FL and NFL from plasma at three different concentrations were assessed. Average recovery was about 100% for both substances. The assay was applied to pharmacokinetic study in 2 healthy volunteers after a single oral administration of 40 mg of FL.     

HPLC-APCI-MS for the determination of teprenone in human plasma: method and clinical application

A sensitive high performance liquid chromatography-atmospheric pressure chemical ionization-mass spectrometry (HPLC-APCI-MS) method for the determination of teprenone (GGA) in human plasma using menatetrenone as the internal standard (I.S.) was established. After protein precipitation with ethanol, the plasma sample was extracted by cyclohexane and separated by high performance liquid chromatography on a reversed phase C8 HPLC column with a mobile phase of water-methanol (4:96, v/v). GGA was determined with atmospheric pressure chemical ionisation-mass spectrometry (APCI-MS). HPLC-APCI-MS was performed in the selected ion monitoring (SIM) mode using target ions at [M+H]+m/z 331.3 for GGA and [M+H]+m/z 445.4 for the I.S. Calibration curve was linear over the range of 0.3-1000 ng/ml. The lower limit of quantification was 0.3 ng/ml. The intra- and inter-batch variability values were less than 7.8% and 8.7%, respectively. The method was successfully applied in the pharmacokinetic study in which plasma concentrations of GGA in 20 healthy Chinese volunteers were determined up to 24 h after administration of capsule containing 50 mg GGA. The maximum GGA plasma concentration (Cmax) was 246.9+/-85.4 ng/ml, the elimination half-life (t1/2) was 3.38+/-1.20 h, and the time to the Cmax was 5.35+/-1.39 h.     

Rapid and sensitive high-performance liquid chromatographic method for the determination of ritonavir in human plasma

Ritonavir is an HIV-1 protease inhibitor that is often used to improve the systemic availability of concurrently administered protease inhibitors by impairing their metabolism through cytochrome P450 (CYP) 3A4. Pharmacodynamic relationships between plasma ritonavir concentrations and efficacy and toxicity have also been described. To date, published high-performance liquid chromatographic (HPLC) methods for the determination of ritonavir in human plasma are often complex, requiring the use of a buffered mobile phase that contains amine-modifiers (i.e. diethylamine, triethylamine). In the method herein, ritonavir was precipitated with acetonitrile plus barium hydroxide and zinc sulphate. Chromatographic separation was accomplished using a C-18 base-deactivated (250 x 4.6 mm I.D., 5 atm particle size) analytic column with a mobile phase composed of acetonitrile:water (52:48, v/v). Quantification was performed at 239 nm. Calibration curves were linear from 0.5-25 microg/ml (R2 > 0.999); percent errors, as a measure of accuracy, were < 12.7%. Intra- and inter-assay relative standard deviations (RSD) were below 12.8%. This method provides a rapid and simple means for the accurate and precise analysis of ritonavir in human plasma. Furthermore, the assay requires neither the use of a buffered mobile phase adjusted to a specific pH, nor the addition of amine modifiers. This method has been successfully used to determine plasma ritonavir concentrations in drug interaction studies.     

高效液相色谱法测定吲达帕胺的血药浓度

目的建立测定吲达帕胺血药浓度的方法。方法选择以乙腈(pH=2.8)磷酸缓冲液(32∶68)为流动相,格列吡嗪为内标,血浆样品以重蒸乙醚为提取溶剂,经DiamonsilC18(150mm×4.6mm,5μm)柱分离后,在紫外吸收波长240nm处进样40μL检测。结果吲达帕胺血浆样品在25～500ng/mL的范围内线性关系良好(r=0.9996,n=6),绝对回收率>67%,相对回收率>92%日内日间的RSD<6%。结论本法简便、准确、灵敏、重现性好,可用于吲达帕胺的药物动力学的研究。     

Rapid and sensitive liquid chromatography-mass spectrometry method for determination of ropinirole in human plasma

A rapid and robust liquid chromatography–mass spectrometry (LC–MS/MS) method was developed for non-ergoline dopamine D₂-receptor agonist, ropinirole in human plasma using Es-citalopram oxalate as an internal standard. The method involves solid phase extraction from plasma, reversed-phase simple isocratic chromatographic conditions and mass spectrometric detection that enables a detection limit at picogram levels. The proposed method was validated with linear range of 20–1200 pg/ml. The extraction recoveries for ropinirole and internal standard were 90.45 and 65.42%, respectively. The R.S.D.% of intra-day and inter-day assay was lower than 15%. For its sensitivity and reliability, the proposed method is particularly suitable for pharmacokinetic studies.     

Rapid and sensitive LC-MS/MS method for determination of Pravastatin in human plasma

快速灵敏的LC-MS/MS方法检测人血浆中普伐他汀的浓度@张敏$Institute of Clinical Pharmacology, Central South University!Changsha 410078,Hunan,China @谭志荣$Institute of Clinical Pharmacology, Central South University!Changsha 410078,Hunan,China @周宏灏$Ins     

A rapid and sensitive liquid chromatography-tandem mass spectrometry method for determination of olopatadine concentration in human plasma

A sensitive and rapid method based on liquid chromatography- tandem mass spectrometry (MS-MS) was developed for the determination of olopatadine in human plasma. Sample preparations were carried out by protein precipitation with the addition of acetonitrile followed by liquid-liquid extraction with ethyl acetate/dichloromethane after internal standard (IS, amitriptyline) spiked. After evaporation to dryness, the resultant residue was reconstituted in mobile phase. Separation of olopatadine and IS from the interferences was achieved on a C(18) column followed by MS-MS detection. The analytes were monitored in the positive ionization mode with a TurboIonspray source. Multiple reaction monitoring using the transition of m/z 338 → 165 and m/z 278 → 91 was performed to quantify olopatadine and IS, respectively. The method had a total chromatographic run time of 3.5 min and linear calibration curves over the concentration range of 0.2-100 ng/mL. The lower limit of quantification was 0.2 ng/mL. For each QC concentration level the intra- and interday precisions were less than 11.4%, and relative errors ranged between -6.40% and 9.26%. The validated method was successfully applied to the quantification of olopatadine concentration in human plasma after administration of olopatadine at an oral dose of 5 mg in order to evaluate the pharmacokinetics.     

A sensitive and simplified HPLC analysis for the determination of fluconazol in human plasma

A sensitive and simplified HPLC assay of fluconazol is described. The calibration curve of fluconazol in plasma ranging 0–10 μ g/ml was linear with the correlation coefficients of 0.9900. The limit of detection was 0.3 μ g/ml. The average recovery of the drug was 89.1±9.05%. After oral administration of single dose(150mg) of fluconazol in man, C_max and T_max were 3 μg/ml and 4hr., respectively.