Simultaneous determination of itraconazole and hydroxyitraconazole in human plasma by liquid chromatography–isotope dilution tandem mass spectrometry method

A rapid and sensitive liquid chromatography–isotope dilution tandem mass spectrometry method was developed and validated for quantification of itraconazole (ITZ) and its active metabolite hydroxyitraconazole (OH‐ITZ ) in human plasma. The plasma samples were extracted with tert‐butyl methyl ether and two isotope‐labeled internal standards (D5‐itraconazole and D5‐hydroxyitraconazole) were used. The chromatographic separation was performed on a Capcell Pak C₁₈ MG III (100 × 2 mm, 5 µm, Shiseido). The protonated ions of analytes were detected in positive ionization in multiple reaction monitoring mode. The plasma method has a lower limit of quantification of 1 ng/mL with a linearity range of 1–500 ng/mL for ITZ and OH‐ITZ using 100 µL of plasma. The recoveries of the method were found to be 69.47–71.98% for ITZ and 75.68–82.52% for OH‐ITZ. The intra‐ and inter‐batch precision was less than 11% for all quality control samples at concentrations of 2.5, 200 and 400 ng/mL. These results indicate that the method was efficient with a short run time (4.5 min) and acceptable accuracy, precision and sensitivity.The validated method was successfully applied to analysis of human plasma samples in pharmacokinetics study. Copyright © 2009 John Wiley & Sons, Ltd.     

Ultra‐high‐performance liquid chromatography–tandem mass spectrometry for pharmacokinetics of bakuchiol in rats

Psoralea Corylifolia L. is a traditional Chinese medicine with many beneficial effects in medical therapies. Bakuchiol was the main active ingredient of Psoralea Corylifolia L., used for the treatment of various diseases and also as a natural food additive. A specific and reliable ultra‐high performance liquid chromatography–tandem mass spectrometry has been developed and fully validated for the quantification of bakuchiol in rat plasma. Chromatographic separation of bakuchiol and an internal standard, daidzein, was achieved on a Hypersil Gold C₁₈ column with gradient elution that consisted of methanol and water at a flow rate of 0.2 mL/min. The compounds were detected at negative ionization mode using mass transition m/z 255.2 → 172.0 and 252.9 → 132.0 for bakuchiol and daidzein, respectively. Good linearity was obtained over the range of 2–1000 ng/mL and the lower limit of quantification was 2 ng/mL. The intra‐ and inter‐day accuracies ranged from 91.1 to 105.7% and precisions (relative standard deviations) were within 9.3%. Bakuchiol was found to be stable under three freeze–thaw cycles, short‐term temperature, post‐preparative and long‐term temperature conditions. The method was applied to a pharmacokinetic study of bakuchiol intravenously administered to rats at a dose of 5 mg/kg. Copyright © 2013 John Wiley & Sons, Ltd.     

Simultaneous determination of residues of thiamethoxam and its metabolite clothianidin in tobacco leaf and soil using liquid chromatography‐tandem mass spectrometry

A simple analytical method was developed to simultaneously determine thiamethoxam and its metabolite, clothianidin, in fresh tobacco leaf, soil and cured tobacco leaf using liquid chromatography with tandem mass spectrometry. Thiamethoxam and clothianidin in tobacco and soil samples were extracted with acetonitrile containing 0.1% formic acid and purified using an NH₂‐SPE column. The optimized method provided good linearity with coefficients of determination R² ≥ 0.9981. The limits of detection and quantification were between 0.006–0.12 and 0.02–0.4 mg/kg, respectively. Intra‐ and inter‐day recovery assays were used to validate the established method. The average recoveries of thiamethoxam and clothianidin in fresh tobacco leaf, soil and cured tobacco leaf were 75.04–100.47%, 75.86–86.40% and 89.83–99.39%, respectively. The intra‐ and inter‐day relative standard deviations were all <9%. The developed method was successfully applied for the analysis of thiamethoxam and clothianidin residues in actual tobacco and soil samples. The results indicated that the established method met the requirements for the analysis of trace amounts of thiamethoxam and clothianidin in fresh tobacco leaf, soil and cured tobacco leaf.     

Quantification of homoegonol in rat plasma using liquid chromatography–tandem mass spectrometry and its pharmacokinetics application

Homoegonol is a biologically active neolignan isolated from Styrax species with cytotoxic, antimicrobial, anti‐inflammatory and anti‐asthma activities. For the quantification of homoegonol in rat plasma, a selective and sensitive liquid chromatography–tandem mass spectrometric method was developed and validated for the first time using protein precipitation with methanol as a sample clean‐up procedure. The analytes were separated in an Atlantis dC₁₈ column using a gradient elution of methanol and 0.1% formic acid, and mass‐to‐charge ratios were determined in selective reaction monitoring mode using tandem mass spectrometry with m/z 343.12 > 296.97 for homoegonol and m/z 517.30 > 282.90 for udenafil (internal standard). The standard curve was linear over the concentration ranges of 1 ? 500 ng/mL using a 30 μL rat plasma sample. The coefficient of variation and relative error for intra‐ and inter‐assay at four quality control levels were 3.9–10.0 and ‐3.3–2.7%, respectively. The overall recovery of homoegonol from rat plasma using protein precipitation was 99.7 ± 7.7%. The pharmacokinetics parameters of homoegonol were dose‐independent after both intravenous (1, 2.5 and 5 mg/kg doses) and oral (5, 10 and 20 mg/kg doses) administration in male Sprague–Dawley rats. Copyright © 2014 John Wiley & Sons, Ltd.     

Development and validation of a liquid chromatography–tandem mass spectrometry method for topotecan determination in beagle dog plasma and its application in a bioequivalence study

Topotecan (TPT) is an important anti‐cancer drug that inhibits topoisomerase I. A sensitive and robust liquid chromatography–tandem mass spectrometry (LC‐MS/MS) method that potentially determines TPT in beagle dog plasma is needed for a bioequivalence study of TPT formulations. We developed and validated LC‐MS/MS to evaluate TPT in beagle dog plasma in terms of specificity, linearity, precision, accuracy, stability, extraction recovery and matrix effect. Plasma samples were treated with an Ostro^TM sorbent plate (a robust and effective tool) to eliminate phospholipids and proteins before analysis. TPT and camptothecin (internal standard) were separated on an Acquity UPLC BEH C₁₈ column (1.7 µm, 2.1 × 50 mm) with 0.1% formic acid and methanol as the mobile phase at a flow rate of 0.25 mL/min. TPT was analyzed using positive ion electrospray ionization in multiple‐reaction monitoring mode. The obtained lower limit of quantitation was 1 ng/mL (signal‐to‐noise ratio > 10). The standard calibration curve for TPT was linear (correlation coefficient > 0.99) at the concentration range of 1–400 ng/mL. The intra‐day and inter‐day precision, accuracy, stability, extraction recovery and matrix effect of TPT were within the acceptable limits. The validated method was successfully applied in a bioequivalence study of TPT in healthy beagle dogs. Copyright © 2013 John Wiley & Sons, Ltd.     

A liquid chromatography–tandem mass spectrometry method to simultaneously determinate dichlorvos and phoxim in tobacco

A simple pretreatment method with liquid chromatography–tandem mass spectrometry (LC–MS/MS) was developed and validated to simultaneously determine dichlorvos and phoxim in tobacco and soil matrices. Satisfactory linearity (R² ≥ 0.9991) of the method was obtained for both analytes. The limits of detection and limits of quantification for dichlorvos and phoxim in three matrices were 0.0015–0.006 and 0.005–0.02 mg/kg, respectively. Average recoveries were 78.24–92.21% for dichlorvos and 76.62–100.51% for phoxim in soil, green tobacco leaves and cured tobacco leaves. The intra‐ and inter‐day relative standard deviations were <6%. The established method was successfully applied for the residual analysis of dichlorvos and phoxim in real soil and tobacco samples. The results indicated that the established method could be used to detect trace amounts of dichlorvos and phoxim in tobacco. The data could also help the Chinese government establish maximum residue limits of dichlorvos and phoxim on tobacco and establish proper and safe use of dichlorvos and phoxim on tobacco plants in China.     

Simultaneous detection of sulfoxaflor and its metabolites,X11719474 and X11721061, in lettuce using a modified QuEChERS extraction method and liquid chromatography–tandem mass spectrometry

An analytical method has been developed to quantify the residual levels of sulfoxaflor and its metabolites (X11719474 and X11721061) in/on cultivated lettuce grown under greenhouse conditions. Samples were extracted and purified using a quick, easy, cheap, effective, rugged, and safe ‘QuEChERS’ method (original version) following systematic method optimization and were analyzed by liquid chromatography–tandem mass spectrometry (LC–MS/MS). Good linearity with coefficient of determination ≥0.9930 was obtained and the limits of detection (LOD) and quantification (LOQ) were in the ranges of 0.003–0.006 and 0.01–0.02 mg/kg, respectively. The recovery rates of both the parent compound and its metabolites (fortified at 10 and 50× the LOQ) estimated from six replicates ranged between 81.9 and 115.5% with a relative standard deviation <12%. The validated method was applied to field‐incurred samples (collected over 7 days) sprayed once or twice with a water‐dispersible granule formulation. Notably, a substantial reduction in rate was observed after 3 days and the half‐life was short, only 1.5 days. The developed method is simple and versatile and can be used for various leafy vegetables.     

Simultaneous determination of cyadox and its metabolites in plasma by high‐performance liquid chromatography tandem mass spectrometry

Cyadox is a novel antimicrobial growth‐promoter of the quinoxalines. For food safety and pharmacokinetic studies, a convenient, sensitive and reproducible LC‐ESI‐MS/MS method was developed for the simultaneous determination of cyadox and its major metabolites, quinoxaline‐2‐carboxylic acid, 1,4‐bisdesoxycyadox, cyadox‐1‐monoxide and cyadox‐4‐monoxide in chicken plasma. Plasma sample was subjected to a simple deproteinisation with acetonitrile. Analysis was performed on a C₁₈ column by detection with mass spectrometry in multiple reaction monitoring mode. A gradient elution program with 0.2% formic acid, methanol and acetonitrile was performed at a flow rate of 0.2 mL/min. The decision limits (CCαs) of five analytes in plasma ranged from 1.0 to 4.0 μg/L, and the detection capabilities (CCβs) were <10 μg/L. Acceptable precision and accuracy were obtained for concentrations over the standard curve range. The extraction recoveries of five analytes were between 87.4 and 93.9% in plasma at the spiked levels of 5 (10)–200 μg/L with the relative standard deviations <10% for each analyte. The developed method demonstrated a satisfactory applicability in real plasma samples.     

Quantification of chlordesmethyldiazepam by liquid chromatography–tandem mass spectrometry: application to a cloxazolam bioequivalence study

A rapid, sensitive and specific LC‐MS/MS method was developed and validated for quantifying chlordesmethyldiazepam (CDDZ or delorazepam), the active metabolite of cloxazolam, in human plasma. In the analytical assay, bromazepam (internal standard) and CDDZ were extracted using a liquid‐liquid extraction (diethyl‐ether/hexane, 80/20, v/v) procedure. The LC‐MS/MS method on a RP‐C18 column had an overall run time of 5.0 min and was linear (1/x weighted) over the range 0.5–50 ng/mL (R > 0.999). The between‐run precision was 8.0% (1.5 ng/mL), 7.6% (9 ng/mL), 7.4% (40 ng/mL), and 10.9% at the low limit of quantification—LLOQ (0.500 ng/mL). The between‐run accuracies were 0.1, –1.5, –2.7 and 8.7% for the above mentioned concentrations, respectively. All current bioanalytical method validation requirements (FDA and ANVISA) were achieved and it was applied to the bioequivalence study (Cloxazolam—test, Eurofarma Lab. Ltda and Olcadil®— reference, Novartis Biociências S/A). The relative bioavailability between both formulations was assessed by calculating individual test/reference ratios for Cmax, AUClast and AUC0‐inf. The pharmacokinetic profiles indicated bioequivalence since all ratios were as proposed by FDA and ANVISA. Copyright © 2009 John Wiley & Sons, Ltd.     

Surrogate analyte‐based quantification of main endocannabinoids in whole blood using liquid chromatography–tandem mass spectrometry

Endocannabinoids (eCBs) are endogenous ligands of the endocannabinoid system that are known to regulate several physiological and behavioral processes. Previous studies have developed methods for the detection of main eCBs including arachidonylethanolamide (AEA) and 2‐arachidonoylglycerol (2‐AG), mostly in serum or plasma. Whole blood is a superior biomaterial for eCBs analysis owing to the nature of the shortened isolation procedure and decreased risk of 2‐AG isomerization during preparation. In this study, a surrogate analyte‐based liquid chromatography–tandem mass spectrometry assay was developed for the measurement of AEA, 2‐AG and its isomer 1‐arachidonoylglycerol (1‐AG) using a maximum of 100 μL whole blood. Chromatographic separation was achieved using a reverse‐phase column and a gradient elution. Detection was performed in selected reaction monitoring mode with an electrospray ionization source. The limits of detection of three eCBs were 0.05–0.1 ng/mL. Good linearity was observed over the concentration range. Intra‐ and inter‐assay accuracy and precision were ≤10.9 and ≤8.7% at four quality control levels. The response factor and parallelism experiment illustrated that the surrogate analytes were suitable for accurate quantification of the main eCBs in whole blood. This surrogate analyte approach was successfully applied to authentic blood samples obtained from alcohol negative drivers and those under the influence of alcohol.     

Investigation of sarin(Se) reactivity against human plasma proteins using liquid chromatography–tandem mass spectrometry

Electron ionization mass spectrum of sarin(Se) was interpreted in compare of sarin MS spectrum. Inhibition of butyrylcholinesterase of human plasma by sarin and sarin(Se) was determined spectrophotometrically using modified Ellman method. It appeared that after incubation with sarin and sarin(Se), cholinesterase inhibition were 93% and 83%, respectively. Sarin, sarin(Se), and sarin(Se)‐d₇ were spiked into a vial containing human plasma, and albumin adduct metabolites were identified using liquid chromatography–tandem mass spectrometry. The experiments show that these agents are attached to tyrosine on albumin in human blood. Corresponding deuterated adducts were used to confirm the proposed mechanisms for the formation of the fragments in mass spectrometry experiments.     

Determination of a novel paclitaxel derivative (NPD‐103) in human plasma by ultra‐performance liquid chromatography–tandem mass spectrometry

A sensitive and specific ultra‐performance liquid chromatography–tandem mass spectrometry (UPLC‐MS‐MS) method for quantification of a newly developed anticancer agent NPD‐103 has been established. An aliquot of human plasma sample (200 µL) was spiked with ¹³C‐labeled paclitaxel (internal standard) and extracted with 1.3 mL of tert‐butyl methyl ether. NPD‐103 was quantitated on a C₁₈ column with methanol–0.1% formic acid (75:25, v/v) as mobile phase using UPLC‐MS‐MS operating in positive electrospray ionization mode with a total run time of 3.0 min. For NPD‐103 at the concentrations of 1.0, 5.0 and 10.0 µg/mL in human plasma, the absolute extraction recoveries were 95.58, 102.43 and 97.77%, respectively. The linear quantification range of the method was 0.1–20.0 µg/mL in human plasma with linear correlation coefficients greater than 0.999. The intra‐ and inter‐day accuracy for NPD‐103 at 1.0, 5.0 and 10.0 µg/mL levels in human plasma fell into the ranges of 95.29–100.00% and 91.04–94.21%, and the intra‐ and inter‐day precisions were in the ranges of 8.96–11.79% and 7.25–10.63%, respectively. This assay is applied to determination of half‐life of NPD‐103 in human plasma. Copyright © 2008 John Wiley & Sons, Ltd.     

Determination of sphingosine kinase activity in biological samples by liquid chromatography–tandem mass spectrometry

Sphingosine kinase (SphK) is a key enzyme in modulating the levels of sphingosine 1‐phosphate (S1P) as well as an important enzyme in numerous biological responses. Using C17‐sphingosine as a substrate, we established a rapid, sensitive and highly efficient method for determination of SphK activity by analyzing the product C17‐sphingosine 1‐phosphate (C17‐S1P) using liquid chromatography–tandem mass spectrometry. The standard curve for C17‐S1P was linear over a wide range (10–1000 ng/mL) with correlation coefficient (r²) greater than 0.999. The lower limit of quantification for C17‐S1P was 10 ng/mL. The K_m values for C17‐sphingosine and ATP were determined to be 28.17 and 188.5 mM, respectively. More importantly, the SphK activity dramatically increased in cultured HEK 293 cells expressing wild‐type SphK1 as well as cells treated with tumor necrosis factor‐a, a sphingosine kinase activator. In contrast, the SphK activity decreased in cultured HEK 293 cells treated with dimethylsphngosine, a sphingosine kinase inhibitor. In conclusion, this method was sensitive and rapid in the determination of SphK acitivity, providing striking utilities in exploring the sphingosine kinase signaling pathway and screening active compounds targeting SphK activity. Copyright © 2010 John Wiley & Sons, Ltd.     

Simultaneous assay of sildenafil and desmethylsildenafil in neonatal plasma by ultra‐performance liquid chromatography–tandem mass spectrometry

Sildenafil is used to treat pulmonary hypertension in neonatal and pediatric patients. Pharmacokinetic studies in these patients are complicated by the limited sample volume. We present the validation results of an assay method to quantitate sildenafil and desmethylsildenafil simultaneously in 50 µL of plasma. Deuterated sildenafil was used as an internal standard. After liquid–liquid extraction, analytes were separated on an ultra‐performance liquid chromatography (UPLC)‐column and quantified via tandem mass spectrometry. The calibration range was linear, with acceptable accuracy and a precision of <15% for both compounds. The lower limits of quantification were 1 ng/mL. Matrix effects were present, but inter‐plasma batch variability was under 12%. The method was successfully applied to samples from a pharmacokinetic study into sildenafil pharmacokinetics in neonates, making maximum use of the limited number and amount of plasma samples available. Copyright © 2009 John Wiley & Sons, Ltd.     

Pharmacokinetics and tissue distribution of coptisine in rats after oral administration by liquid chromatography–mass spectrometry

Coptisine, one of the main components isolated from Coptidis rhizoma, has been reported to have many beneficial pharmacological effects including anti‐inflammatory, anti‐hypercholesterolemia, neuroprotective and cardioprotective properties. However, to date the information related to the in vivo pharmacokinetics (PK) of coptisine is very limited. The purposes of our study are to establish a fast and sensitive quantification method of coptisine using liquid chromatography–mass spectrometry (LC–MS) and evaluate the PK profile of coptisine in rats. The calibration curve for coptisine was linear from 0.78 to 50 ng/mL. After single‐dose oral administration of coptisine, the mean peak plasma concentration values for groups treated with 30, 75 and 150 mg/kg doses ranged from 44.15 to 66.89 ng/mL, and the mean area under the concentration–time curve values ranged from 63.24 to 87.97 mg/L h. The absolute bioavailability was calculated to range from 1.87 to 0.52%. Coptisine remained in all analyzed samples at low concentrations after oral administration of 30 mg/kg.     

Simultaneous quantification of atenolol and chlorthalidone in human plasma by ultra‐performance liquid chromatography–tandem mass spectrometry

A simple, sensitive and reproducible ultra‐performance liquid chromatography–tandem mass spectrometry method has been developed for the simultaneous determination of atenolol, a β‐adrenergic receptor‐blocker and chlorthalidone, a monosulfonamyl diuretic in human plasma, using atenolol‐d7 and chlorthalidone‐d4 as the internal standards (ISs). Following solid‐phase extraction on Phenomenex Strata‐X cartridges using 100 μL human plasma sample, the analytes and ISs were separated on an Acquity UPLC BEH C₁₈ (50 mm × 2.1 mm, 1.7 µm) column using a mobile phase consisting of 0.1% formic acid–acetonitrile (25:75, v/v). A tandem mass spectrometer equipped with electrospray ionization was used as a detector in the positive ionization mode for both analytes. The linear concentration range was established as 0.50–500 ng/mL for atenolol and 0.25–150 ng/mL for chlorthalidone. Extraction recoveries were within 95–103% and ion suppression/enhancement, expressed as IS‐normalized matrix factors, ranged from 0.95 to 1.06 for both the analytes. Intra‐batch and inter‐batch precision (CV) and accuracy values were 2.37–5.91 and 96.1–103.2%, respectively. Stability of analytes in plasma was evaluated under different conditions, such as bench‐top, freeze–thaw, dry and wet extract and long‐term. The developed method was superior to the existing methods for the simultaneous determination of atenolol and chlorthalidone in human plasma with respect to the sensitivity, chromatographic analysis time and plasma volume for processing. Further, it was successfully applied to support a bioequivalence study of 50 mg atenolol + 12.5 mg chlorthalidone in 28 healthy Indian subjects. Copyright © 2015 John Wiley & Sons, Ltd.     

Amantadine hydrochloride monitoring by dried plasma spot technique: High‐performance liquid chromatography–tandem mass spectrometry based clinical assay

Amantadine plasma concentrations correlate well with desired therapeutic effects and adverse outcomes; information on amantadine exposure could be useful when multiple amantadine clearance pathways are impaired or non‐compliance is suspected. Micro‐sampling strategies, like dried plasma spot, would be particularly useful because ambulatory patients that do not attend a clinic can easily sample a few drops of blood by themselves at the required time of the dosing interval. We developed and validated a dried‐plasma‐spot‐based high performance liquid chromatography–tandem mass spectrometry assay to quantify amantadine. This assay met relevant validation requirements within a hematocrit range of 20–50% and was linear from 100 to 2000 ng/mL. Amantadine was stable in dried plasma spots for up to 21 days at room temperature, regardless of whether the dried plasma spot was protected from light or not. The correlation between paired dried and wet plasma concentrations was assessed in 52 patients. Deming regression coefficients between wet plasma and simultaneously pipetted dried plasma spots were used to predict plasma concentrations. Bland–Altman plots revealed a strong agreement between dried and wet plasma concentrations, supporting the clinical usefulness of dried plasma spots for amantadine monitoring with a self‐sampling strategy at a convenient time and place for the patient.     

Simultaneous quantification of oxybutynin and its active metabolite N‐desethyl oxybutynin in rat plasma by ultra‐high‐performance liquid chromatography–tandem mass spectrometry and its application in a pharmacokinetic study of oxybutynin transdermal patch

A rapid, selective and sensitive ultra‐high‐performance liquid chromatography–tandem mass spectrometry method was developed to simultaneously determine oxybutynin and its active metabolite N‐desethyl oxybutynin in rat plasma. A 0.1 mL sample of plasma was extracted with n‐hexane. Chromatographic separation was performed on a UPLC BEH C₁₈ column (2.1 × 100 mm i.d.,1.7 μm) with mobile phase of methanol–water (containing 2 mmol/L ammonium acetate and 0.1% formic acid; 90:10, v/v). The detection was performed in positive selected reaction monitoring mode. Each plasma sample was chromatographed within 3 min. The linear calibration curves were obtained in the concentration range of 0.0944–189 ng/mL (r ≥ 0.99) for oxybutynin and 0.226–18.0 ng/mL (r ≥ 0.99) for N‐desethyl oxybutynin. The intra‐ and inter‐day precision (relative standard deviation) values were not more than 14% and the accuracy (relative error) was within ±7.6%. The method described was superior to previous methods for the quantitation of oxybutynin with three product ions and was successfully applied to a pharmacokinetic study of oxybutynin and its active metabolite N‐desethyl oxybutynin in rat plasma after transdermal administration.     

Simultaneous determination of five triterpene acids in rat plasma by liquid chromatography–mass spectrometry and its application in pharmacokinetic study after oral administration of Folium Eriobotryae effective fraction

Folium Eriobotryae effective fraction (FEA), the extract of Folium Eriobotryae, had been used as anti‐hyperglycemia and anti‐hyperlipemia medicine in China. A previous study indicated that euscaphic acid, maslinic acid, corosolic acid, oleanolic acid and ursolic acid, the five structurally similar triterpene acids (containing two groups of structural isomers), are the major components of FEA. In the present study, we developed a specific and reliable LC‐MS method for simultaneous determination of the five triterpene acids in rat plasma, and further investigated their pharmacokinetic properties after oral administration of FEA. Following a simple sample preparation, chromatographic separation was achieved on a C₁₈ column with a mobile phase composed of methanol–0.1% ammonium acetate (80:20, v/v). Quantification was achieved by monitoring the selected ions at m/z 487.6 for euscaphic acid, m/z 471.5 for maslinic acid and corosolic acid, m/z 455.5 for oleanolic acid and ursolic acid and m/z 469.5 for internal standard. The method was validated to be specific, accurate and precise over the concentration ranges of 10–3000 ng/mL with limits of detections of 5 ng/mL for the five triterpene acids. Finally, the method was successfully applied to the pharmacokinetic study of the five structurally similar triterpene acids in rats after oral administration of FEA. Copyright © 2015 John Wiley & Sons, Ltd.     

Determination of the novel antiarrhythmic drug sulcardine sulfate in human plasma by liquid chromatography tandem mass spectrometry and its application in a clinical pharmacokinetic study

Sulcardine sulfate (Sul), a novel antiarrhythmic agent, is currently in phase I and phase II clinical trials. To elucidate its clinical pharmacokinetic characteristics, a rapid and accurate liquid chromatography–tandem mass spectrometry (LC–MS/MS) method has been developed and validated for the quantification of Sul in human plasma. Plasma samples were precipitated by acetonitrile and isotope‐labeled sulcardine was added as internal standard. The analysis was carried out on a Capcell Pak C₁₈ MG III column (100 × 2.0 mm, 5 μm) with 0.1% formic acid in acetonitrile solution and water (17:83, v/v) as mobile phase. The linear range was 5.0–1000 ng/mL for Sul, with a lower limit of quantification of 5.0 ng/mL. The intra‐ and inter‐batch CVs were within ±11.0% and the accuracies were 4.9–107.3%. Our method, for the first time, allows the rapid (only 3.0 min) and accurate quantification of Sul in human plasma. The method has been successfully applied in the pharmacokinetic study of Sul in a clinical trial following oral administration of Sul to healthy volunteers. Copyright © 2016 John Wiley & Sons, Ltd.