To investigate the pharmacokinetics of felodipine in the plasma of healthy Chinese volunteers, 30 healthy volunteers received a single oral dose of 5 mg of extended release felodipine tablets. The felodipine was extra...To investigate the pharmacokinetics of felodipine in the plasma of healthy Chinese volunteers, 30 healthy volunteers received a single oral dose of 5 mg of extended release felodipine tablets. The felodipine was extracted from the matrix with a liquid-liquid extract procedure and analyzed by high-performance liquid chromatography-tandem mass spectrometry in the multiple reaction monitoring（MRM） mode using an electrospray ion source with positive ion detection. The method was validated over a felodipine concentration range of 0. 05-10.00 ng/mL in human plasma. Its main pharmacokinetic parameters values were： ρmax = （ 1.67 ± 0. 84 ） ng/mL, occurring at （ 3.93 3± 2. 49 ） h; the plasma elimination half-life： （23. 08 3± 9. 48） h and the area under the plasma concentration versus time curve： （29. 94 ± 14. 39） ng · h/mL. The validation results demonstrated that this method showed a satisfactory precision and accuracy across the calibration range. The procedure involved minimal drug administration, sample preparation, and a 2. 5-min chromatographic run time. It was well suited to clinical studies of the drug involving large numbers of samples.展开更多
A simple and high throughput method was developed and validated for simultaneous determination of valproic acid and its two toxicant ene-metabolites, 2-enevalproic acid and 4-enevalproic acid in epilepsy patient plasm...A simple and high throughput method was developed and validated for simultaneous determination of valproic acid and its two toxicant ene-metabolites, 2-enevalproic acid and 4-enevalproic acid in epilepsy patient plasma using liquid chromatography-tandem mass spectrometry. Probenecid was used as in- ternal standard and solid-phase extraction was selected for sample preparation. A chromatographic separation was performed on an Agilent Poroshell SB-C18 column （50 mm × 4.6 mm i.d., 2.7μm） by an optimized gradient elution at a flow rate of 0.9 mL/min. The total run time was 7 rain. Electrospray ionization was used in negative ion mode by multiple reaction monitoring of the precursor-to-product ion transitions at m/z 143.0→143.0 for valproic acid, m/z 140.9 →140.9 for 2-enevalproic acid and 4-enevalproic acid for their poor fragments, and m/z 283.9→239,9 for probenecid. The results showed good linearity ofvalproic acid, 2-enevalproic acid and 4-enevalproic acid in their respective linear ranges. The correlation coefficients were more than 0.998, The intra- and inter-day precision of the assay was less than 11.0% and the accuracy ranged from 2% to 12%. This analytical method was successfully applied to assay plasma concentrations of valproic acid and its two ene-metabolites in epilepsy patient plasma and used for therapeutic drug monitoring.展开更多
An analytical method based on solid phase extraction was developed and validated for analysis of adefovir in human plasma. Adefovir-d4 was used as an internal standard and Synergi MAX RP80A （150rnmx4.6mm. 41am） colu...An analytical method based on solid phase extraction was developed and validated for analysis of adefovir in human plasma. Adefovir-d4 was used as an internal standard and Synergi MAX RP80A （150rnmx4.6mm. 41am） column provided the desired chromatographic separation of compounds followed by detection with mass spectrometry. The method used simple isocratic chromato- graphic condition and mass spectrometric detection in the positive ionization mode. The calibration cuives were linear over the range of 0.50-42.47 ng/mL with the lower limit of quantitation validated at 0.50 ng/mL. Matrix effect was assessed by post-column infusion experiment to monitor phospholipids and post- extraction addition experiment was performed. The degree of matrix effect for adefovir was determined as 7.5% and ion-enhancement in five different lots of human plasma was 7.1% and had no impact on study samples analysis with 4.5 rain run time. The intra- and inter-day precision values were within 7.7% and 7.8%, respectively, for adefovir at the lower limit of quantification level. Validated bioanalytical method was successfully applied to clinical sample analysis.展开更多
Background Stomach cancer is among the most commonly occurring malignancies worldwide. It would be beneficial to develop a urine-based assay whereby patients with undiagnosed stomach cancer could be screened and their...Background Stomach cancer is among the most commonly occurring malignancies worldwide. It would be beneficial to develop a urine-based assay whereby patients with undiagnosed stomach cancer could be screened and their cancer detected in the eadiest stages. Methods A urinary metabonomics method based on ultra-performance liquid chromatography combined with quadruple time-of-flight mass spectrometry was used to analyze urine samples from patients with stomach cancer and healthy controls. Results Statistical analysis revealed a clear separation of patients and healthy controls using the aforementioned methodology. Some significantly changed metabolites were identified. Conclusions Use of the metabonomics method in patients with stomach cancer could effectively detect distinct changes in urinary metabolites and had the capacity to detect cancer; therefore, it may be a valuable tool in earlier diagnosis. Furthermore, the detection and identification of altered metabolites in the current study may help elucidate possible mechanisms involved in stomach cancer.展开更多
In this study, a method based on low temperature purification （LTP） coupled with liquid chromatography-tandem mass spectrometry （LC-MS/MS） was developed for the determination of abamectin （ABA） and ivermectin （...In this study, a method based on low temperature purification （LTP） coupled with liquid chromatography-tandem mass spectrometry （LC-MS/MS） was developed for the determination of abamectin （ABA） and ivermectin （IVR） in edible oils. ABA and IVR were extracted using conventional liquid-liquid extraction followed by purification via precipitation of interfering fatty components at low temperature without an additional cleanup step. LTP is simple, easy to use, labour-saving and cost effective, and requires reduced amounts of organic solvent. The linear ranges of ABA and IVR were 5- 1000 t^g/L using matrix-matched standards. Limits of detection （LOD） and limits of quantification （LOQ） were in the range of 0.1-0.4 i^g/kg and 0.3-1.3 p^g/kg, respectively. The LOQs were below the strictest maximum residue limits established by Codex Alimentarius Commission. Recoveries at three spiked levels of 10, 20 and 100 i^g/kg in peanut oil, corn oil, olive oil, soybean oil and lard ranged from 71.1% to 119.3% with relative standard deviations of 3.2%-10.3%, which were in agreement with those obtained by the solid phase extraction method. The proposed method was utilized in the analysis of 10 edible oil samples from local market and neither ABA nor IVR was detected. As far as we know, this is the first time that LTP is applied to the determination of avermectins in edible oils.展开更多
基金Supported by the National Natural Science Foundation of China(No. 30472053)
文摘To investigate the pharmacokinetics of felodipine in the plasma of healthy Chinese volunteers, 30 healthy volunteers received a single oral dose of 5 mg of extended release felodipine tablets. The felodipine was extracted from the matrix with a liquid-liquid extract procedure and analyzed by high-performance liquid chromatography-tandem mass spectrometry in the multiple reaction monitoring（MRM） mode using an electrospray ion source with positive ion detection. The method was validated over a felodipine concentration range of 0. 05-10.00 ng/mL in human plasma. Its main pharmacokinetic parameters values were： ρmax = （ 1.67 ± 0. 84 ） ng/mL, occurring at （ 3.93 3± 2. 49 ） h; the plasma elimination half-life： （23. 08 3± 9. 48） h and the area under the plasma concentration versus time curve： （29. 94 ± 14. 39） ng · h/mL. The validation results demonstrated that this method showed a satisfactory precision and accuracy across the calibration range. The procedure involved minimal drug administration, sample preparation, and a 2. 5-min chromatographic run time. It was well suited to clinical studies of the drug involving large numbers of samples.
文摘A simple and high throughput method was developed and validated for simultaneous determination of valproic acid and its two toxicant ene-metabolites, 2-enevalproic acid and 4-enevalproic acid in epilepsy patient plasma using liquid chromatography-tandem mass spectrometry. Probenecid was used as in- ternal standard and solid-phase extraction was selected for sample preparation. A chromatographic separation was performed on an Agilent Poroshell SB-C18 column （50 mm × 4.6 mm i.d., 2.7μm） by an optimized gradient elution at a flow rate of 0.9 mL/min. The total run time was 7 rain. Electrospray ionization was used in negative ion mode by multiple reaction monitoring of the precursor-to-product ion transitions at m/z 143.0→143.0 for valproic acid, m/z 140.9 →140.9 for 2-enevalproic acid and 4-enevalproic acid for their poor fragments, and m/z 283.9→239,9 for probenecid. The results showed good linearity ofvalproic acid, 2-enevalproic acid and 4-enevalproic acid in their respective linear ranges. The correlation coefficients were more than 0.998, The intra- and inter-day precision of the assay was less than 11.0% and the accuracy ranged from 2% to 12%. This analytical method was successfully applied to assay plasma concentrations of valproic acid and its two ene-metabolites in epilepsy patient plasma and used for therapeutic drug monitoring.
基金support and facilities received from Ranbaxy Research Laboratories Gurgaon,India
文摘An analytical method based on solid phase extraction was developed and validated for analysis of adefovir in human plasma. Adefovir-d4 was used as an internal standard and Synergi MAX RP80A （150rnmx4.6mm. 41am） column provided the desired chromatographic separation of compounds followed by detection with mass spectrometry. The method used simple isocratic chromato- graphic condition and mass spectrometric detection in the positive ionization mode. The calibration cuives were linear over the range of 0.50-42.47 ng/mL with the lower limit of quantitation validated at 0.50 ng/mL. Matrix effect was assessed by post-column infusion experiment to monitor phospholipids and post- extraction addition experiment was performed. The degree of matrix effect for adefovir was determined as 7.5% and ion-enhancement in five different lots of human plasma was 7.1% and had no impact on study samples analysis with 4.5 rain run time. The intra- and inter-day precision values were within 7.7% and 7.8%, respectively, for adefovir at the lower limit of quantification level. Validated bioanalytical method was successfully applied to clinical sample analysis.
文摘Background Stomach cancer is among the most commonly occurring malignancies worldwide. It would be beneficial to develop a urine-based assay whereby patients with undiagnosed stomach cancer could be screened and their cancer detected in the eadiest stages. Methods A urinary metabonomics method based on ultra-performance liquid chromatography combined with quadruple time-of-flight mass spectrometry was used to analyze urine samples from patients with stomach cancer and healthy controls. Results Statistical analysis revealed a clear separation of patients and healthy controls using the aforementioned methodology. Some significantly changed metabolites were identified. Conclusions Use of the metabonomics method in patients with stomach cancer could effectively detect distinct changes in urinary metabolites and had the capacity to detect cancer; therefore, it may be a valuable tool in earlier diagnosis. Furthermore, the detection and identification of altered metabolites in the current study may help elucidate possible mechanisms involved in stomach cancer.
基金supported by National Natural Science Foundation of China(No.21305019)Special Fund forAgro-Scientific Research in the Public Interest(No.201303088)President Fund of Guangdong Academy of Agricultural Sciences(No.201218)
文摘In this study, a method based on low temperature purification （LTP） coupled with liquid chromatography-tandem mass spectrometry （LC-MS/MS） was developed for the determination of abamectin （ABA） and ivermectin （IVR） in edible oils. ABA and IVR were extracted using conventional liquid-liquid extraction followed by purification via precipitation of interfering fatty components at low temperature without an additional cleanup step. LTP is simple, easy to use, labour-saving and cost effective, and requires reduced amounts of organic solvent. The linear ranges of ABA and IVR were 5- 1000 t^g/L using matrix-matched standards. Limits of detection （LOD） and limits of quantification （LOQ） were in the range of 0.1-0.4 i^g/kg and 0.3-1.3 p^g/kg, respectively. The LOQs were below the strictest maximum residue limits established by Codex Alimentarius Commission. Recoveries at three spiked levels of 10, 20 and 100 i^g/kg in peanut oil, corn oil, olive oil, soybean oil and lard ranged from 71.1% to 119.3% with relative standard deviations of 3.2%-10.3%, which were in agreement with those obtained by the solid phase extraction method. The proposed method was utilized in the analysis of 10 edible oil samples from local market and neither ABA nor IVR was detected. As far as we know, this is the first time that LTP is applied to the determination of avermectins in edible oils.
