Simultaneous determination of niflumic acid and its prodrug, talniflumate in human plasma by high performance liquid chromatography

A high-performance liquid chromatographic (HPLC) method has been developed for the simultaneous determination of niflumic acid and its prodrug, talniflumate, in human plasma. Niflumic acid and talniflumate were eluted isocratically with methanol-water (73:27, v/v, adjusted to pH 3.5 by acetic acid) at a fl ow rate of 1 mL/min. Indomethacin was used as an internal standard. Signals were monitored by an UV detector at 288 nm. Retention times of indomethacin, niflumic acid and talniflumate were 5.9, 7.2 and 13.5 min, respectively. Calibration plots were linear over the range 50-5000 ng/mL for niflumic acid and 100-5000 ng/mL for talniflumate. The limits of quantitation were 50 ng/mL for niflumic acid and 100 ng/mL for talniflumate. The intra- and inter-day relative standard deviations (RSD) of niflumic acid and talniflumate were less than 10% and the accuracies were higher than 90%. This method is rapid, sensitive and reproducible for the determination of niflumic acid and talniflumate in human plasma.     

Fast simultaneous LC/MS/MS determination of 10 active compounds in human serum for therapeutic drug monitoring in psychiatric medication

A UPLC/MS/MS method with simple protein precipitation has been validated for the fast simultaneous analysis of agomelatine, asenapine, amisulpride, iloperidone, zotepine, melperone, ziprasidone, vilazodone, aripiprazole and its metabolite dehydro‐aripiprazole in human serum. Alprenolol was applied as an internal standard. A BEH C₁₈ (2.1 × 50 mm, 1.7 µm) column provided chromatographic separation of analytes using a binary mobile phase gradient (A, 2 mmol/L ammonium acetate, 0.1% formic acid in 5% acetonitrile, v/v/v; B, 2 mmol/L ammonium acetate, 0.1% formic acid in 95% acetonitrile, v/v/v). Mass spectrometric detection was performed in the positive electrospray ionization mode and ion suppression owing to matrix effects was evaluated. The validation criteria were determined: linearity, precision, accuracy, recovery, limit of detection, limit of quantification, reproducibility and matrix effect. The concentration range was as follows: 0.25–1000 ng/mL for agomelatine; 0.25–100 ng/mL for asenapine and iloperidone; 2.5–1000 ng/mL for amisulpride, aripiprazole, vilazodone and zotepine; 2.3–924.6 ng/mL for dehydroaripiprazole; 2.2–878.4 ng/mL for melperone; and 2.2–883.5 ng/mL for ziprasidone. Limits of quantitation below a therapeutic reference range were achieved for all analytes. Intra‐run precision of 0.4–5.5 %, inter‐run precision of 0.6–8.2% and overall recovery of 87.9–114.1% were obtained. The validated method was successfully implemented into routine practice for therapeutic drug monitoring in our hospital. Copyright © 2015 John Wiley & Sons, Ltd.     

Simultaneous determination of serum propafenone and its metabolites using high‐performance liquid chromatography

Propafenone, a class Ic antiarrhythmic agent, is metabolized to 5‐hydroxypropafeone (5‐OHP) and N‐depropylpropafenone (NDPP). Simultaneous determination of serum propafenone and its metabolites was performed using HPLC equipped with a conventional octadecylsilyl silica column and ultraviolet detector. The wavelength was set at 250 nm. Propafenone and its metabolites in the serum were extracted using diethyl ether. The mobile phase solution, comprising 1‐pentanesulfonic acid sodium salt (0.1 m ), acetonitrile and acetic acid (280:185:2.5, v/v/v), was pumped at a flow rate of 1 mL/min. The recoveries of propafenone, 5‐OHP and NDPP were greater than 85, 82 and 60%, respectively, with the coefficients of variation (CVs) less than 5.4, 1.9 and 2.9%, respectively. The calibration curves were linear for a concentration range of 12.5–1500 ng/mL for propafenone and 2–500 ng/mL for 5‐OHP and NDPP (r > 0.999). CVs in the intraday assays were 1.0–3.8% for propafenone, 0.6–2.0% for 5‐OHP and 0.6–1.7% for NDPP. CVs in interday assays were 1.3–7.7% for propafenone, 1.1–6.5% for 5‐OHP and 5.4–8.0% for NDPP. The present HPLC method can be used to assess the disposition of propafenone and its metabolites for pharmacokinetic studies and therapeutic drug monitoring of propafenone.     

Determination of paeoniflorin,calycosin‐7‐O‐β‐d‐glucoside,ononin, calycosin and formononetin in rat plasma after oral administration of Buyang Huanwu decoction for their pharmacokinetic study by liquid chromatography–mass spectrometry

The purpose of this study was to simultaneously investigate the pharmacokinetics of five bioactive compounds in rat plasma after oral administration of Buyang Huanwu decoction (BYHWD) using high‐performance liquid chromatography coupled with mass spectrometry (HPLC‐MS). The separations were performed on a Thermo Hypersil Gold C₁₈ analytical column (50 × 2.1 mm, 3 µm) with the column temperature kept at 30°C. The quantitative analysis was performed using a quadrupole mass spectrometer detector operated under selected ion monitoring mode. A linear gradient elution of A (0.1% formic acid solution) and B (100% acetonitrile) was used at a flow rate of 0.2 mL/min. The method was validated within the concentration ranges 1.8–450, 6.0–1500, 2.0–500, 1.2–300 and 1.2–150 ng/mL for paeoniflorin, calycosin‐7‐O‐β‐d ‐glucoside, ononin, calycosin and formononetin, respectively. The calibration curves were linear with correlation coefficients > 0.99. The lower limits of quantitations were < 6.0 ng/mL. The method was further applied to assess the pharmacokinetics of the five bioactive constituents of BYHWD in rat plasma. Copyright © 2010 John Wiley & Sons, Ltd.     

A sensitive column-switching HPLC method for aripiprazole and dehydroaripiprazole and its application to human pharmacokinetic studies

A simple and sensitive column‐switching HPLC‐UV method was developed for the simultaneous determination of aripiprazole, a novel atypical antipsychotic drug, and its active metabolite, dehydroaripiprazole in human plasma. Aripiprazole, its active metabolite and 7‐[5‐[4‐(3‐chloro‐2‐methylphenyl)‐1‐piperazinyl]pentyloxy]‐3,4‐dihydro‐2(1H)‐quinolinone (OPC‐14558) as an internal standard were extracted from 1 mL of plasma using a mixture of chloroform/n‐heptane (3:7, v/v), and the extract was injected into a column I (TSK BSA‐ODS/S precolumn, 5 μm) for cleanup and column II (C₁₈ STR ODS‐II analytical column, 5 μm) for separation. Peaks were detected with an UV detector set at a wavelength of 254 nm, and the total time for chromatographic separation was ～20 min. Mean absolute recoveries were 74.0 and 74.7% for aripiprazole and dehydroaripiprazole, respectively. Intra‐ and inter‐day CVs were less than 7.5 and 7.1% for aripiprazole concentrations ranging from 2 to 600 ng/mL, and 9.2 and 4.5% for dehydroaripiprazole concentrations ranging from 2 to 160 ng/mL. The validated concentration ranges for this method were 1–500 ng/mL and the limits of detection were 0.5 ng/mL for both aripiprazole and dehydroaripiprazole. This method was applied to pharmacokinetic study in human volunteers and patients taking aripiprazole.     

A sensitive LC–MS/MS‐based bioanalytical method for quantification of salviaflaside and rosmarinic acid in rat plasma and its application in a pharmacokinetic study

A selective and sensitive liquid chromatography tandem mass spectrometry method was developed for the simultaneous determination of salviaflaside and rosmarinic acid in rat plasma. Sample preparation was carried out through liquid–liquid extraction with ethyl acetate using curculigoside as internal standard (IS). The analytes were determined by selected reaction monitoring operated in the positive ESI mode. Chromatographic separation was performed on an Agilent Eclipse Plus C₁₈ column (100 × 4.6 mm, 1.8 μm) with a mobile phase consisting of methanol–water–formic acid (50:50:0.1, v/v/v) at a flow rate of 0.3 mL/min. The run time was 1.9 min per sample and the injection volume was 5 μL. The method had an LLOQ of 1.6 ng/mL for salviaflaside and 0.94 ng/mL for rosmarinic acid in plasma. The linear calibration curves were fitted over the range of 1.6–320 ng/mL for salviaflaside and 0.94–188 ng/mL for rosmarinic acid in plasma with correlation coefficients (r²) >0.99. Intra‐ and inter‐day precisions (relative standard deviation) were < 13.5%, and accuracies (relative error) were between −8.6% and 14.5% for all quality control samples. The method was validated and applied to the pharmacokinetics of salviaflaside and rosmarinic acid in plasma after oral administration of Prunella vulgaris extract to rats.     

HPLC with fluorescence detection assay of perampanel,a novel AMPA receptor antagonist,in human plasma for clinical pharmacokinetic studies

Perampanel (Fycompa®), a novel α‐amino‐3‐hydroxy‐5‐methyl‐4‐isoxazolepropionic acid (AMPA) receptor antagonist, is registered for the adjunctive treatment of patients (aged ≥12 years) with refractory partial‐onset seizures. To support therapeutic drug monitoring, a simple high‐performance liquid chromatography (HPLC) assay with fluorescence detection was developed to determine perampanel concentrations in human plasma and validated to support clinical trials. Human plasma samples (1.0 mL) were processed by liquid extraction using diethyl ether, followed by chromatographic separation on a YMC Pack Pro C₁₈ column (150 × 4.6 mm i.d., 5 µm) with isocratic elution of acetonitrile–water–acetic acid–sodium acetate (840:560:3:1.8, v/v/v/w) at a flow rate of 1.0 mL/min. Column eluent was monitored at excitation and emission wavelengths of 290 and 430 nm, respectively. The assay was linear (range 1.0–500 ng/mL) and this could be extended to 25 µg/mL by 50‐fold dilution integrity. No endogenous peaks were detected in the elution of analytes in drug‐free blank human plasma from six individuals and no interference was observed with co‐medications tested. Intra‐ and inter‐batch reproducibility studies demonstrated accuracy and precision within the acceptance criteria of bioanalytical guidelines. Validation data demonstrated that our assay is simple, selective, reproducible and suitable for therapeutic drug monitoring of perampanel. Copyright © 2015 John Wiley & Sons, Ltd.     

Simultaneous determination of tandospirone and its active metabolite, 1‐[2‐pyrimidyl]‐piperazine in rat plasma by LC–MS/MS and its application to a pharmacokinetic study

A rapid, sensitive and selective liquid chromatography–tandem mass spectrometry method for the detection of tandospirone (TDS) and its active metabolite 1‐[2‐pyrimidyl]‐piperazine (1‐PP) in Sprague–Dawley rat plasma is described. It was employed in a pharmacokinetic study. These analytes and the internal standards were extracted from plasma using protein precipitation with acetonitrile, then separated on a CAPCELL PAK ADME C₁₈ column using a mobile phase of acetonitrile and 5 mm ammonium formate acidified with formic acid (0.1%, v/v) at a total flow rate of 0.4 mL/min. The detection was performed with a tandem mass spectrometer equipped with an electrospray ionization source. The method was validated to quantify the concentration ranges of 1.000–500.0 ng/mL for TDS and 10.00–500.0 ng/mL for 1‐PP. Total time for each chromatograph was 3.0 min. The intra‐day precision was between 1.42 and 6.69% and the accuracy ranged from 95.74 to 110.18% for all analytes. Inter‐day precision and accuracy ranged from 2.47 to 6.02% and from 98.37 to 105.62%, respectively. The lower limits of quantification were 1.000 ng/mL for TDS and 10.00 ng/mL for 1‐PP. This method provided a fast, sensitive and selective analytical tool for quantification of tandospirone and its metabolite 1‐PP in plasma necessary for the pharmacokinetic investigation.     

A rapid and simple HPLC method for the determination of curcumin in rat plasma: assay development,validation and application to a pharmacokinetic study of curcumin liposome

This paper describes a sensitive, specific and rapid high‐performance liquid chromatography (HPLC) method for the determination of curcumin in rat plasma. After a simple step of protein precipitation in 96‐well format using acetonitrile containing the internal standard (IS), emodin, plasma samples were analyzed by reverse‐phase HPLC. Curcumin and the IS emodin were separated on a Diamonsil C₁₈ analytical column (4.6 × 100 mm, 5 µm) using acetonitrile–5% acetic acid (75:25, v/v) as mobile phase at a flow rate of 1.0 mL/min. The method was sensitive with a lower limit of quantitation of 1 ng/mL, with good linearity (r² ≥ 0.999) over the linear range 1–500 ng/mL. All the validation data, such as accuracy and precision, were within the required limits. A run time of 3.0 min for each sample made high‐throughput bioanalysis possible. The assay method was successfully applied to the study of the pharmacokinetics of curcumin liposome in rats. Copyright © 2009 John Wiley & Sons, Ltd.     

Simultaneous quantitative analysis of dextromethorphan,dextrorphan and chlorphenamine in human plasma by liquid chromatography–electrospray tandem mass spectrometry

A sensitive and accurate HPLC‐MS/MS method was developed for the simultaneous determination of dextromethorphan, dextrorphan and chlorphenamine in human plasma. Three analytes were extracted from plasma by liquid–liquid extraction using ethyl acetate and separated on a Kromasil 60‐5CN column (3 µm, 2.1 × 150 mm) with mobile phase of acetonitrile–water (containing 0.1% formic acid; 50:50, v/v) at a flow rate of 0.2 mL/min. Quantification was performed on a triple quadrupole tandem mass spectrometer in multiple reaction monitoring mode using positive electrospray ionization. The calibration curve was linear over the range of 0.01–5 ng/mL for dextromethorphan, 0.02–5 ng/mL for dextrorphan and 0.025–20 ng/mL for chlorphenamine. The lower limits of quantification for dextromethorphan, dextrorphan and chlorphenamine were 0.01, 0.02 and 0.025 ng/mL, respectively. The intra‐ and inter‐day precisions were within 11% and accuracies were in the range of 92.9–102.5%. All analytes were proved to be stable during sample storage, preparation and analytic procedures. This method was first applied to the pharmacokinetic study in healthy Chinese volunteers after a single oral dose of the formulation containing dextromethorphan hydrobromide (18 mg) and chlorpheniramine malaeate (8 mg). Copyright © 2013 John Wiley & Sons, Ltd.     

Determination of risperidone and 9‐Hydroxyrisperidone using HPLC,in plasma of children and adolescents with emotional and behavioural disorders

A simple, rapid, selective, accurate and precise method is described for the determination of risperidone and its active metabolite, 9‐hydroxyrisperidone, in plasma using a chemical derivative of risperidone (methyl‐risperidone) as the internal standard. The sample workup involved a single‐step extraction of 1 mL plasma, buffered to pH 10, with heptane–isoamyl alcohol (98:2 v/v), then evaporation of the heptane phase and reconstitution of the residue in mobile phase. HPLC separation was carried out at on C₁₈ column using a mobile phase of 0.05 m dipotassium hydrogen orthophosphate (containing 0.3% v/v triethylamine) adjusted to pH 3.7 with orthophosphoric acid (700 mL), and acetonitrile (300 mL). Flow rate was 0.6 mL/min and the detection wavelength was 280 nm. Retention times were 2.6, 3.7 and 5.8 min for 9‐hydroxy risperidone, risperidone and the internal standard, respectively. Linearity in spiked plasma was demonstrated from 2 to 100 ng/mL for both risperidone and 9‐hydroxyrisperidone (r ≥ 0.999). Total imprecision was less than 13% (determined as co‐efficient of variation) and the inaccuracy was less than 12% at spiked concentrations of 5 and 80 ng/mL. The limit of detection, determined as three times the baseline noise, was 1.5 ng/mL. Clinical application of the assay was demonstrated for analysis of post‐dose (0.55–4.0 mg/day) samples from 28 paediatric patients (aged 6.9–17.9 years) who were taking risperidone orally for behavioural and emotional disorders. Copyright © 2009 John Wiley & Sons, Ltd.     

Quantitation of unbound sunitinib and its metabolite N-desethyl sunitinib (SU12662) in human plasma by equilibrium dialysis and liquid chromatography-tandem mass spectrometry: application to a pharmacokinetic study

A rapid, selective, and sensitive liquid chromatography–tandem mass spectrometry method was developed and validated for the simultaneous determination of unbound sunitinib and its active metabolite N‐desethyl sunitinib in plasma. Plasma and post‐dialysis buffer samples were extracted using a liquid–liquid extraction procedure with acetonitrile–n‐butylchloride (1:4, v/v). Chromatographic separation was achieved on a Waters X‐Terra® MS RP₁₈ column with a mobile phase consisting of acetonitrile and water (60:40, v/v) containing formic acid (0.1%, v/v) using an isocratic run, at a flow‐rate of 0.2 mL/min. Analytes were detected by electrospray tandem mass spectrometry in the selective reaction monitoring mode. Linear calibration curves were generated over the ranges 0.1–100 and 0.02–5 ng/mL for sunitinib and 0.2–200 and 0.04–10 ng/mL for N‐desethyl sunitinib in plasma and in phosphate‐buffered solution, respectively. The values for both within‐day and between‐day precision and accuracy were well within the generally accepted criteria for analytical methods. The analytical range was sufficient to determine the unbound and total concentrations of both analytes. The method was applied for measurement unbound concentrations in addition to total concentrations of sunitinib and its metabolite in plasma of a cancer patient receiving 50 mg daily dose. Copyright © 2012 John Wiley & Sons, Ltd.     

Simultaneous determination of sarpogrelate and its active metabolite in human plasma by liquid chromatography with tandem mass spectrometry and its application to a pharmacokinetic study

We established a rapid and simple liquid chromatography with tandem mass spectrometry method for the simultaneous determination of sarpogrelate and its active metabolite, M‐1, in human plasma. Sarpogrelate, M‐1, and the internal standard, ketanserin, were extracted from a 50 μL aliquot of human plasma by protein precipitation using acetonitrile. Chromatographic separation was performed on a Shim‐pack GIS ODS C₁₈ column (100 × 3.0 mm; 3 μm) with an isocratic mobile phase consisting of 10 mM ammonium acetate and acetonitrile (70:30, v/v) at a flow rate of 0.6 mL/min; the total run time was <2.5 min. Mass spectrometric detection was conducted in selected reaction‐monitoring mode with positive electrospray ionization at m/z 430.35 → 135.10 for sarpogrelate, m/z 330.30 → 58.10 for M‐1, and m/z 395.70 → 188.85 for ketanserin. The linear ranges of concentration for sarpogrelate and M‐1 were 1–1000 and 0.5–500 ng/mL, respectively. The coefficient of variation for the assay's precision was ≤9.95%, and the accuracy was 90.6–107%. All analytes were stable under various storage and handling conditions, and no relevant crosstalk and matrix effect was observed. This method was successfully applied to a pharmacokinetic study after oral administration of a 100 mg sarpogrelate tablet to healthy male Korean volunteers.     

HPLC‐ESI‐MS/MS analysis and pharmacokinetics of luteoloside,a potential anticarcinogenic component isolated from Lonicera japonica,in beagle dogs

Luteoloside is a potential anticarcinogenic component isolated from Lonicera japonica, a traditional Chinese medicine (TCM). This study details the development and validation of a sensitive and accurate HPLC‐ESI‐MS/MS method for the quantification of luteoloside in dog plasma. Sample pretreatment includes simple protein precipitation using methanol–acetonitrile (1:1, v/v). A Phenomenex Gemini C₁₈ column (2.0 × 50 mm, i.d., 3.5 µm) was used to separate luteoloside and internal standard by gradient mode with mobile phase consisting of water containing 0.1% formic acid and methanol containing 0.1% formic acid at a flow rate of 0.40 mL/min with a column temperature of 25°C. The detection was performed by positive ion electrospray ionization (ESI) in multiple reaction monitoring mode. The calibration curves were linear (R > 0.995) over the concentration range 1.0–2000 ng/mL and the lower limit of quantification was 1.0 ng/mL. The intra‐day and inter‐day precisions (RSD) were all <15%, accuracies (RE) were within the range of ±15%, and recoveries were between 85.0 and 115%. The validated HPLC‐ESI‐MS/MS method was successfully applied to determine plasma concentrations of luteoloside after intravenous administration of luteoloside at a dose level of 20 mg/kg. Copyright © 2012 John Wiley & Sons, Ltd.     

Determination of ASP3258, a novel phosphodiesterase type 4 inhibitor,in rat plasma by high‐performance liquid chromatography with fluorescence detection and its application to pharmacokinetic study

The potent phosphodiesterase 4 inhibitor ASP3258 contains a carboxylic acid moiety and a naphthyridine ring and is a novel therapeutic agent for asthma and chronic obstructive pulmonary disease. To support the drug development of ASP3258, we developed and validated a simple method for its determination in rat plasma. Following the addition of the analog AS1406604‐00 as an internal standard, plasma samples were processed using C₁₈‐bonded solid‐phase extraction cartridges under acidic conditions and injected into a high‐performance liquid chromatography system with fluorescence detection. Chromatographic separation was achieved on a Shiseido Capcell Pak C₁₈ UG120 column (3.0 × 150 mm, 5 µm) with a mobile phase consisting of acetonitrile–0.5% acetic acid (50:50, v/v). HPLC eluent was monitored with a fluorescence detector set at a wavelength of 315 nm for excitation and 365 nm for emission. The calibration curve was linear over a range of 2.5–250 ng/mL. Validation data demonstrated that the method is selective, sensitive and accurate. In addition, the present method was successfully applied to rat plasma samples from a pharmacokinetic study. Copyright © 2014 John Wiley & Sons, Ltd.     

A simple and rapid method to assess lycopene in multiple layers of skin samples

Topical application of lycopene is a convenient way to restore antioxidants depleted from the skin by UV radiation and achieve protection against premature aging and cancer. In this study, a simple, rapid and reproducible method to quantify lycopene in different skin layers was developed, validated and employed to assess this compound after skin penetration studies. Lycopene was extracted from the stratum corneum (SC) and viable epidermis and dermis (ED) by vortex homogenization and bath sonication in a mixture of acetonitrile and methanol (52:48, v/v). Lycopene was assayed by HPLC using a C₁₈ column, and acetonitrile:methanol (52:48, v/v) as mobile phase. The quantification limit of lycopene in samples of SC and ED was 35 ng/mL and the assay was linear from 35 to 2000 ng/mL. Within‐day and between‐days assays coefficients of variation and relative errors (indicative of precision and accuracy) were less than 15% (or 20% for the limit of quantification). Lycopene recovery from SC and ED was dependent on the spiked concentration: for 50 ng/mL, recoveries were 88.3 and 90.5%; for 100–1000 ng/mL, recoveries were 68.6–74.9%. This method has a potential application for lycopene quantification during formulation development and evaluation in the dermatological field. Copyright © 2009 John Wiley & Sons, Ltd.     

Determination of ibudilast in human serum by high‐performance liquid chromatography for pharmacokinetic study

A simple, accurate, precise and cost effective reversed‐phase HPLC method was developed to determine the concentration of ibudilast in human serum. Ibudilast and an internal standard, butyl 4‐hydroxybenzoate, were extracted by liquid–liquid extraction with methyl tert‐butyl ether. HPLC analysis was carried out under the following conditions: a Luna C₁₈(2) 5 μm column, a mobile phase of acetonitrile–0.02% phosphoric acid (50 : 50, v/v, adjusted to pH 6.0 with triethylamine) and a UV detector at 319 nm. The chromatograms showed good resolution and sensitivity as well as no interference from the human serum. The calibration curves were linear over the concentration range, 1–100 ng/mL, for serum with correlation coefficients >0.999. The intra‐ and inter‐day assay precision as well as the accuracy fulfilled the international requirements. The mean absolute recovery for human serum was 101.7 ± 6.1%. The lower limit of quantitation in human serum was 1 ng/mL, which is sensitive enough for pharmacokinetic studies. Stability studies revealed that ibudilast in human serum was stable during storage as well as during the assay procedure. This method was applied successfully to an examination of the pharmacokinetics of ibudilast in human subjects following a single oral dose of an ibudilast (10 mg) capsule. Copyright © 2009 John Wiley & Sons, Ltd.     

超高效液相色谱-串联四极杆飞行时间质谱和超高效液相色谱-串联三重四极杆质谱用于血浆中苦杏仁苷及其代谢产物野黑樱苷的定性和定量分析

建立了大鼠灌胃麻杏石甘汤后血浆中苦杏仁苷、野黑樱苷的定性及定量方法。样品经液液萃取净化处理,定性采用超高效液相色谱-串联四极杆飞行时间质谱仪（UPLC-QTOF-MS/MS）,经Shim-pack XR-ODS Ⅲ色谱柱（75 mm×2.0 mm,1.6 μm）分离,定量采用超高效液相色谱-串联三重四极杆质谱仪（UPLC-Q-TRAP-MS）,经Agilent C₁₈色谱柱（50 mm×2.1 mm,1.7 μm）分离,电喷雾负离子化（ESI）及MRM模式测定,流动相均为乙腈-0.1%（v/v）甲酸水溶液。结果显示苦杏仁苷、野黑樱苷在相应浓度范围内线性关系良好（相关系数分别为0.9990、0.9970）,精密度（RSD）小于9.20%,回收率为82.33%~95.25%,检出限（LOD）约为0.50 ng/mL。本方法快速简便,为血浆样品中苦杏仁苷、野黑樱苷的定性和定量分析提供良好参考。     

A new metabolite of nodakenetin by rat liver microsomes and its quantification by RP‐HPLC method

The biotransformation of nodakenetin (NANI) by rat liver microsomes in vitro was investigated. Two major polar metabolites were produced by liver microsomes from phenobarbital‐pretreated rats and detected by reversed‐phase high‐performance liquid chromatography (RP‐HPLC) analysis. The chemical structures of two metabolites were firmly identified as 3′(R)‐hydroxy‐nodakenetin‐3′‐ol and 3′(S)‐hydroxy‐nodakenetin‐3′‐ol, respectively, on the basis of their ¹H‐NMR, MS and optical rotation analysis. The latter was a new compound. A sensitive, selective and simple RP‐HPLC method has been developed for the simultaneous determination of NANI and its two major metabolites in rat liver microsomes. Chromatographic conditions comprise a C₁₈ column, a mobile phase with MeOH‐H₂O (40 : 60, v/v), a total run time of 40 min, and ultraviolet absorbance detection at 330 nm. In the rat heat‐inactivated liver microsomal supernatant, the lower limits of detection and quantification of metabolite I, metabolite II and NANI were 5.0, 2.0, 10.0 ng/mL and 20.0, 5.0, 50.0 ng/mL, respectively, and their calibration curves were linear over the concentration range 50–400, 20–120 and 150–24000 ng/mL, respectively. The results provided a firm basis for further evaluating the pharmacokinetics and clinical efficacy of NANI. Copyright © 2009 John Wiley & Sons, Ltd.     

Sensitive, selective and rapid determination of bupropion and its major active metabolite, hydroxybupropion, in human plasma by LC-MS/MS: application to a bioequivalence study in healthy Indian subjects

A sensitive, selective and rapid liquid chromatography tandem mass spectrometry (LC‐MS/MS) method was developed for the simultaneous determination of bupropion (BUP) and its major active metabolite hydroxybupropion (HBUP) in human plasma. Separation of both the analytes and venlafaxine as internal standard (IS) from 50 μL human plasma was carried out by solid‐phase extraction. The chromatographic separation of the analytes was achieved on a Zorbax Eclipse XDB C₁₈ (150 × 4.6 mm, 5 µm) analytical column using isocratic mobile phase consisting of 20 mm ammonium acetate–methanol (10:90, v/v), with a resolution factor of 3.5. The method was validated over a wide dynamic concentration range of 0.1–350 ng/mL for BUP and 0.1–600 ng/mL for HBUP. The matrix effect was assessed by post‐column infusion and the mean process efficiency was 96.08 and 94.40% for BUP and HBUP, respectively. The method was successfully applied to a bioequivalence study of 150 mg BUP (test and reference) extended release tablet formulation in 12 healthy Indian male subjects under fed conditions. Copyright © 2011 John Wiley & Sons, Ltd.