Application of a Sensitive, Rapid and Validated LC–MS–MS Method for the Determination of Carvedilol in Human Plasma

Carvedilol was quantified in human plasma after a single 25 mg oral dose of the drug was given to 26 healthy volunteers. An applied Biosystems Sciex API 3200 triple quadrupole mass spectrometer in multiple reaction monitoring mode, using electrospray ionization in the positive ion mode was used. Simple solid phase extraction was followed by C₁₈ reverse phase chromatography and tandem mass spectrometric detection using propranalol as the internal standard. The mean recovery for carvedilol was 91.2% with a lower limit of quantification of 0.5 ng mL^?1. This validated assay method makes use of the increased sensitivity and selectivity of tandem mass spectrometry detection to allow for a more rapid and selective method for the determination of carvedilol in human plasma.     

LC-MS–MS Determination of Pregabalin in Human Plasma

A rapid, sensitive and specific method to quantify pregabalin in human plasma using metaxalone as the internal standard is described. Sample preparation involved simple protein precipitation by using acetronitrile as solvent. The extract was analyzed by high-performance liquid chromatography coupled to electrospray tandem mass spectrometry (LC-MS–MS). Chromatography was performed isocratically on Thermo Hypurity C₁₈ 5 μm analytical column, (50 mm × 4.6 mm i.d.). The assay of pegabalin was linear calibration curve over the range 10.000–10000.000 ng mL^?1. The lower limit of quantification was 10.000 ng mL^?1 in plasma. The method was successfully applied to the bioequivalence study of pregabalin capsules (150.0 mg) administered as a single oral dose.     

LC-MS–MS Determination of Pregabalin in Human Plasma

A rapid, sensitive and specific method to quantify pregabalin in human plasma using metaxalone as the internal standard is described. Sample preparation involved simple protein precipitation by using acetronitrile as solvent. The extract was analyzed by high-performance liquid chromatography coupled to electrospray tandem mass spectrometry (LC-MS–MS). Chromatography was performed isocratically on Thermo Hypurity C₁₈ 5 μm analytical column, (50 mm × 4.6 mm i.d.). The assay of pegabalin was linear calibration curve over the range 10.000–10000.000 ng mL⁻¹. The lower limit of quantification was 10.000 ng mL⁻¹ in plasma. The method was successfully applied to the bioequivalence study of pregabalin capsules (150.0 mg) administered as a single oral dose.

     

Rapid Liquid Chromatographic – Tandem Mass Spectrometric Method for the Quantification of Pentoxifylline in Human Plasma

A simple, rapid, sensitive and selective liquid chromatography / tandem mass spectrometry method was developed and validated for the quantification of pentoxifylline, a haemorheological agent. The analyte and internal standard, tamsulosin were extracted by liquid-liquid extraction with ethyl acetate and were separated using an isocratic mobile phase on a reverse phase C₁₈ column. The analytes were analyzed by mass spectrometry in the multiple reaction monitoring mode using the respective [M+H]⁺ ions, m/z 279/138 for pentoxifylline and m/z 409/228 for the IS. The assay exhibited a linear dynamic range of 2–1000 ng mL⁻¹ for pentoxifylline in human plasma. The lower limit of quantification was 2 ng mL⁻¹ with a relative standard deviation of less than 10%. Acceptable precision and accuracy were obtained for concentrations over the standard curve range. A run time of 1.5 min for each sample made it possible to analyze more than 400 human plasma samples per day. The validated method has been successfully used to analyze human plasma samples for application in pharmacokinetic, bioavailability or bioequivalence studies. Revised: 4 and 20 October 2005     

Alternative LC–MS–MS Method for Simultaneous Determination of Proguanil, Its Active Metabolite in Human Plasma and Application to a Bioequivalence Study

An alternative rapid and sensitive liquid chromatography–tandem mass spectrometry method has been developed and validated for simultaneous analysis of proguanil (PRO) and cycloguanil (CYC) in human plasma. The analytes were extracted from human plasma by solid phase extraction. Riluzole (RIL) was used as an internal standard for proguanil and cycloguanil. A HyPURITY Advance C18 column provided chromatographic separation of analytes followed by detection with mass spectrometry. The method involves simple isocratic chromatography conditions and mass spectrometric detection in the positive ionization mode using an API-4000 system. The proposed method has been validated with linear range of 1.5–150.0 ng mL^?1 for PRO and 0.5–50.0 ng mL^?1 for CYC. The inter-run and intra-run precision values are within 2.54, 9.19% for PRO and 1.99, 10.69% for CYC at LOQ levels. The overall recoveries for PRO and CYC were 102.52 and 106.72%, respectively. Total elution time was as low as 2.50 min. This validated method was used successfully for analysis of plasma samples from a bioequivalence study.     

High-throughput quantification of perindopril in human plasma by liquid chromatography/tandem mass spectrometry: application to a bioequivalence study

A simple, sensitive and rapid high-performance liquid chromatography/positive ion electrospray tandem mass spectrometry method was developed and validated for the quantification of perindopril in human plasma. Following liquid-liquid extraction, the analytes were separated using an isocratic mobile phase on a reversed-phase column and analyzed by mass spectrometry in the multiple reaction monitoring mode using the respective [M+H](+) ions, m/z 369/172 for perindopril and m/z 417/234 for the internal standard. The method exhibited a linear dynamic range of 0.1-100 ng/mL for perindopril in human plasma. The lower limit of quantification was 0.1 ng/mL with a relative standard deviation of less than 6.1%. Acceptable precision and accuracy were obtained for concentrations over the standard curve range. A run time of 2.0 min for each sample made it possible to analyze more than 450 human plasma samples per day. The validated method has been successfully used to analyze human plasma samples for application in pharmacokinetic, bioavailability and bioequivalence studies.     

Determination of Memantine in Human Plasma by LC–MS–MS: Application to a Pharmacokinetic Study

A sensitive and selective liquid chromatography–tandem mass spectrometry method for the determination of memantine was developed and validated over the linearity range 0.1–25 ng mL^?1 with 0.5 mL of plasma using procainamide as the internal standard. This analysis was carried out on a Cosmosil 5C₁₈-MS column and the mobile phase was composed of methanol: 0.5% formic acid (50:50, v/v). Detection was performed on a triple–quadrupole tandem mass spectrometer using positive ion mode electrospray ionization and quantification was performed by multiple reaction monitoring mode. The MS–MS ion transitions monitored were m/z 180 → 107 and 236 → 163 for memantine and procainamide, respectively. The between- and within-day precision was less than 10.9% and accuracy was less than 2.5%. The lower limit of quantification (LLOQ) was 0.1 ng mL^?1. The method proved to be accurate and specific, and was applied to the pharmacokinetic study of memantine in healthy Chinese volunteers.     

Rapid and Selective LC�CMS�CMS Method for the Determination of cyclo-trans-4-l-Hydroxyprolyl-l-serine (JBP485) in Rat Plasma

A rapid and selective liquid chromatographic/tandem mass spectrometric method for the determination of JBP485 was developed and validated. Following protein precipitation, the analyte and internal standard (JBP923) were separated from human plasma using an isocratic mobile phase on an Elite Kromasil C18 column. An API 3200 tandem mass spectrometer equipped with a Turbo ionSpray ionization source was used as the detector and operated in the positive ion mode. Multiple reaction monitoring using the precursor to product ion combinations of m/z 201.2 ?? 86.2 and m/z 219.2 ?? 86.2 was performed to quantify JBP485 and JBP923, respectively. The method was linear in the concentration range of 0.10?C50.00 ??g mL^?1 using 100 ??L of plasma. The lower limit of quantification was 0.10 ??g mL^?1. The intra- and inter-day relative standard deviations over the entire concentration range were less than 6.65%. Accuracy determined at three concentrations (0.25, 4.00 and 25.00 ??g mL^?1 for JBP485) ranged from ?0.78 to 2.74% in terms of relative error. Each plasma sample was chromatographed within 2.0 min. The method was successfully applied to characterize the pharmacokinetic profiles of JBP485 in rats after an intravenous injection of 6.25 mg kg^?1 JBP485.     

Rapid and Sensitive LC−MS–MS Method for the Determination of Sarpogrelate in Human Plasma

A rapid and sensitive liquid chromatographic–tandem mass spectrometric method has been developed and validated for the estimation of sarpogrelate in human plasma. Sarpogrelate was extracted from human plasma by solid-phase extraction. Temocapril was used as the internal standard. Heated electron spray ionization mass spectrometry was performed on a TSQ Quantum Ultra MS system. The LC column was a Hypurity C₁₈ and the mobile phase was 2 mM ammonium formate (pH 3.00 ± 0.05):acetonitrile (30:70 v/v). A flow rate of 0.250 mL min^?1 was used. The quantitative analyses were carried out in the positive ion and full scan mode over the mass range m/z 60–500. The capillary, vaporiser temperatures were 325 and 200 °C respectively. The sheath gas pressure, spray voltage, collision energy and tube lense were 40, 3,500 V, 19 V, 198 V, respectively, and the mass spectra of the drugs were recorded by total ion monitoring. Retention times and characteristic mass fragments were recorded and the chosen diagnostic mass fragments were monitored in the mass chromatography mode. Signal intensities of each of the mass fragments: m/z 477 [M + H]⁺ for temocapril, m/z 430 [M + H]⁺ for sarpogrelate, were used for quantification. The calibration curves (the ratio between the peak areas as signal intensities of the drug analyzed and that of the internal standard (temocapril: m/z 477 [M + H]⁺) vs. the concentration of drug) exhibited linearity over the concentration range 5.00–2,500.00 ng mL^?1 human plasma. The recovery and the accuracy were calculated by comparing the peak areas as the signal intensities of each mass fragment for the drug in spiked samples after solid-phase extraction from human plasma to the peak area as the signal intensity of the mass fragment of internal standard sample. The method involves a rapid solid phase extraction from plasma, simple isocratic chromatography conditions and mass spectrometric detection that enables detection up to picogram levels with a total run time of 3.0 min only. The method was validated over the range of 5.0–2,500.0 ng mL^?1. The absolute recoveries for sarpogrelate (93.72%) and IS (91.42%) achieved from spiked plasma samples were consistent and reproducible.     

A simple,selective and rapid validated method for estimation of anastrazole in human plasma by liquid chromatography–tandem mass spectrometry and its application to bioequivalence study

A rapid, simple and specific method for estimation of anastrazole in human plasma was validated using letrozole as internal standard. The analyte and internal standard were extracted from plasma using simple solid‐phase extraction. The compound were separated on a reverse‐phase column with an isocratic mobile phase consisting of 0.1% formic acid in water and acetonitrile (12 : 88, v/v) and detected by tandem mass spectrometry in positive ion mode. The ion transitions recorded in multiple reaction monitoring mode were m/z 294.1 → 225.1 for anastrazole and m/z 286.1 → 217.1 for internal standard. Linearity in plasma was observed over the concentration range 0.3–30 ng/mL for anastrazole. The mean recovery for anastrazole was 83.7% with a lower limit of quantification of 0.3 ng/mL. The coefficient of variation of the assay was less than 6.8% and the accuracy was 96.1–102.2%. The validated method was applied to a bioequivalence study of 1 mg anastrazole tablet in healthy human volunteers. Copyright © 2009 John Wiley & Sons, Ltd.     

HILIC-MS-MS for the Quantification of Pidotimod in Human Plasma

A method for fast, sensitive, and specific hydrophilic interaction chromatography combined with tandem mass spectrometry (HILIC-MS/MS) was developed for the first time to determine the level of pidotimod in human plasma. With rosiglitazone as internal standard, analysis was carried out on a HILIC column (150 mm × 2.1 mm, 3.5 ??m) using a mobile phase consisting of methanol:0.2% formic acid (60:40, v/v). Detection was carried out by tandem mass spectrometry using electrospray ionization (ESI). Linear calibration curves were obtained in the concentration range of 11.2?C1.12 × 10⁴ ng mL^?1 for pidotimod, with a lower limit of quantification of 11.2 ng mL^?1. The intra- and inter-day precision values were high, with standard deviations lower than 15%, and the accuracy, in terms of relative error, ranged from ?10.5 to 9.4% at all quality control (QC) levels.     

Liquid chromatography/negative ion electrospray tandem mass spectrometry method for the quantification of fluvastatin in human plasma: validation and its application to pharmacokinetic studies

A simple, sensitive and rapid high-performance liquid chromatography/negative ion electrospray tandem mass spectrometry method was developed and validated for the assay of fluvastatin in human plasma. Following solid-phase extraction, the analytes were separated using an isocratic mobile phase on a reversed-phase column and analyzed by mass spectrometry in the multiple reaction monitoring mode using the respective [M-H]- ions, m/z 410/348 for fluvastatin and m/z 480/418 for the internal standard. The assay exhibited a linear dynamic range of 2-500 ng/mL for fluvastatin in human plasma. The lower limit of quantification was 2 ng/mL with a relative standard deviation of less than 5%. Acceptable precision and accuracy were obtained for concentrations over the standard curve range. A run time of 1.5 min for each sample made it possible to analyze more than 400 human plasma samples per day. The validated method has been successfully used to analyze human plasma samples for application in pharmacokinetic, bioavailability or bioequivalence studies.     

Quantification of clopidogrel in human plasma by sensitive liquid chromatography/tandem mass spectrometry

A simple, sensitive and rapid high-performance liquid chromatography/positive electrospray ionization tandem mass spectrometry method was developed and validated for the assay of clopidogrel in human plasma. Following liquid-liquid extraction, the analytes were separated using an isocratic mobile phase on a reversed-phase column and analyzed by mass spectrometry in the multiple reaction monitoring mode using the respective [M+H](+) ions, m/z 322/212 for clopidogrel and m/z 264/154 for the internal standard. The assay exhibited a linear dynamic range of 5-6000 pg/mL for clopidogrel in human plasma. The lower limit of quantification was 5 pg/mL with a relative standard deviation of less than 8%. Acceptable precision and accuracy were obtained for concentrations over the standard curve range. A run time of 2.5 min for each sample made it possible to analyze more than 400 human plasma samples per day. The validated method has been successfully used to analyze human plasma samples for application in pharmacokinetic, bioavailability or bioequivalence studies.     

Quantification of fexofenadine in human plasma by liquid chromatography coupled to electrospray tandem mass spectrometry using mosapride as internal standard

A rapid high-performance liquid chromatography/positive ion electrospray tandem mass spectrometry method was developed and validated for the quantification of fexofenadine in human plasma using mosapride as internal standard. Following solid-phase extraction, the analytes were separated using an isocratic mobile phase on a reverse-phase column and analyzed by MS/MS in the multiple reaction monitoring mode using the respective [M+H]+ ions, m/z 502/466 for fexofenadine and m/z 422/198 for the IS. The method exhibited a linear dynamic range of 1-500 ng/mL for fexofenadine in human plasma. The lower limit of quantification was 1 ng/mL with a relative standard deviation of less than 5% for fexofenadine. Acceptable precision and accuracy were obtained for concentrations over the standard curve range. The total chromatographic run time of 2 min for each sample made it possible to analyze more than 400 human plasma samples per day. The validated method has been successfully used to analyze human plasma samples for application in pharmacokinetic, bioavailability or bioequivalence studies.     

Identification and quantification of salinomycin in intoxicated human plasma by liquid chromatography–electrospray tandem mass spectrometry

Salinomycin is a polyether ionophore antibiotic that is widely used in poultry and livestock. Exposure of humans to salinomycin via inhalation or ingestion can cause severe toxicity. The aim of the present work was to develop a simple and sensitive liquid chromatography–tandem mass spectrometry (LC-MS/MS) method for the rapid identification and quantification of salinomycin in human plasma. After removing protein using methanol, plasma samples were eluted from a Waters Xterra ^® MS C18 column with an isocratic mobile phase. Detection and quantification of the drug were performed with a triple-quadruple mass spectrometer by monitoring for two specific transitions in the electrospray, positive-ion, multiple-reaction monitoring mode. Assay validation showed good linearity (r ²?=?0.998). The detection and quantification limits of the method were 0.6 and 16 pg/mL, respectively. The inter- and intraday coefficients of variation for the assay were both <15%. Twelve authentic plasma samples from intoxicated patients were analyzed using this method. Salinomycin was detected in six samples, at concentrations of between 0.6 and 46.5 pg/mL. The described assay method allows the sensitive and rapid identification and quantification of salinomycin in human plasma, and thus provides a valuable tool for the specific diagnosis of salinomycin intoxication in clinical and emergency rescue practice.     

Sensitive and Selective LC-MS-MS Assay for the Quantification of Palonosetron in Human Plasma and Its Application to a Pharmacokinetic Study

A highly sensitive and selective liquid chromatography-tandem mass spectrometry method was developed for the determination of palonosetron in human plasma samples. Chromatographic conditions and mass spectral parameters were optimized in order to achieve a limit of quantification of approximately 0.03 ng mL^?1. Palonosetron and citalopram (internal standard) were extracted by liquid–liquid extraction under alkaline conditions using saturated sodium bicarbonate. Separation was achieved with a Hanbon Lichrospher C₁₈ column and detection was carried out by tandem mass spectrometry using positive electrospray ionization in selected reaction monitoring mode. The target ions of palonosetron and citalopram were to m/z 297.00 → 297.00 and 325.00 → 325.00 respectively. Calibration curves were linear over the range of approximately 0.03–10 ng mL^?1. Precision and accuracy of this method was acceptable. The method was successfully applied to a pharmacokinetic study with healthy Chinese volunteers after intravenous administration of a single dose of 0.125, 0.25 or 0.5 mg palonosetron hydrochloride.     

Sensitive determination of phloroglucinol in human plasma by liquid chromatography-tandem mass spectrometry

Summary A sensitive and selective liquid chromatographic method coupled with tandem mass spectrometry (LC-MS-MS) was developed for the quantification of phloroglucinol in human plasma. Resorcinol was used as internal standard, with plasma samples extracted using ethyl acetate. A centrifuged upper layer was then evaporated and reconstituted with mobile phase. The reconsituted samples were injected into a C₁₈ XTerra MS column (2.1×100 mm) with 3.5 μm particle size. The analytical column lasted for at least 500 injections. The mobile phase was 15% acetonitrile (pH 3.0), with a flow rate at 100 μL min¹. The mass spectrometer was operated in positive ion mode using electrospray ionization. Using MS-MS in multiple reaction monitoring (MRM) mode, phloroglucinol was detected without severe interferences from the plasma matrix. Phloroglucinol produced a parent molecule ([M+H]⁺) atm/z 127 and a corresponding product ion atm/z 8l. Detection of phloroglucinol in human plasma was accurate and precise, with quantification on limit at 0.5 ng mL¹. The method has been successfully applied to a study of phloroglucinol in human specimens.     

Simultaneous Determination of Atenolol and Chlorthalidone by LC–MS–MS in Human Plasma

A simple, sensitive, selective and rapid liquid chromatography–tandem mass spectrometry method was developed and validated for the simultaneous separation and quantitation of atenolol and chlorthalidone in human plasma using metoprolol and hydrochlorothiazide as internal standard. Following solid phase extraction, the analytes were separated by an isocratic mobile phase on a reversed-phase C₁₈ column and analyzed by MS in the multiple reaction-monitoring mode (atenolol in positive and chlorthalidone in the negative ion mode). The limit of quantitation for this method was 10 and 15 ng mL^?1 and the linear dynamic range was generally 10–2,050 ng mL^?1 and 15–3,035 ng mL^?1 for atenolol and chlorthalidone, respectively.     

A Sensitive LC–ESI–MS–MS Method for the Determination of Huperzine A in Human Plasma: Method and Clinical Applications

A sensitive and specific liquid chromatography–electrospray ionization–tandem mass spectrometry method has been developed and validated for the quantification of huperzine A in human plasma. After the addition of trimetazidine, the internal standard (IS) and sodium hydroxide, plasma samples were extracted using 5 mL ethyl acetate. The compounds were separated on an Agilent Zorbax SB C₁₈ column (100 mm × 2.1 mm ID, dp 3.5 μm) using an elution system of 10 mM ammonium acetate solution–methanol–formic acid (18:82:0.1, v/v) as the mobile phase. The quantification of target compounds was obtained by using multiple reaction monitoring (MRM) transitions: m/z 243.1, 210.1 and 267.2, 166.0 were measured in positive mode for huperzine A and IS. Linearity was established for the range of concentrations 0.01–4.0 ng mL^?1 with a coefficient of correlation (r) of 0.9991. The lower limit of quantification (LLOQ) was identifiable and reproducible at 0.01 ng mL^?1. The method has been successfully applied to study the pharmacokinetics of huperzine A in healthy male Chinese volunteers.     

Determination of Imidol in Rat Plasma by UPLC�CMS�CMS and Its Application in a Pharmacokinetic Study

A rapid, sensitive and accurate ultra-performance liquid chromatography/tandem mass spectrometry method was developed and validated for the quantitative determination of imidol in rat plasma for the first time. The analyte and internal standard were extracted from plasma by liquid?Cliquid extraction with diethyl ether. The separation was performed on a BEH C₁₈ column (50 mm × 2.1 mm, 1.7 ??m). The detection was carried out by electrospray ionization mass spectrometry in positive ion mode with multiple reaction monitoring. Linear calibration curves were obtained in the concentration range of 2.5?C2,500 ng mL^?1, with the lower limit of quantification of 2.5 ng mL^?1. The intra- and inter-day precision (RSD) values were below 8% and accuracy (RE) was from ?7.9 to 6.3%. After strict validation, the method was applied successfully to the pharmacokinetic study of imidol in rats after oral and intravenous administration, respectively.