Simultaneous determination of epalrestat and puerarin in rat plasma by UHPLC-MS/MS: Application to their pharmacokinetic interaction study.

In the present study, a simple, rapid and reliable ultrahigh-performance liquid chromatography-tandem mass spectrometric (UHPLC-MS/MS) method was developed and validated to determine simultaneously epalrestat (EPA) and puerarin (PUE) in rat plasma for evaluation of the pharmacokinetic interaction of these two drugs. Both the analytes and glipizide (internal standard, IS) were extracted using a protein precipitation method. The separation was performed on a C18 reversed phase column using acetonitrile and 5 mmol/L ammonium acetate in water as the mobile phase with a gradient elution program. The analytes, including IS, were quantified with multiple reaction monitoring under negative ionization mode. The optimized mass transition ion pairs (m/z) were 318.1 → 274.0 for EPA, 415.1 → 266.9 for PUE and 444.2 → 166.9 for IS. The linear calibration curves for EPA and PUE were obtained in the concentration ranges of 10-4167 and 20-8333 ng/mL, respectively (r > 0.99). The current method was successfully applied for the pharmacokinetic interaction study in rats following administration of EPA and PUE alone or co-administration (EPA 15 mg/kg, oral; PUE 30 mg/kg, intravenous). The results showed that the combination of EPA and PUE could increase t1/2 of EPA and reduce Tmax of EPA. These changes indicated that EPA and PUE might cause drug-drug interactions when co-administrated.

Sun H ，Bo Y ，Zhang M ，Wu X ，Zhou M ，Zhao L ，Xiong Z ... -  《-》

LC-MS/MS method for the quantification of aldose reductase inhibitor-epalrestat and application to pharmacokinetic study.

A simple and rapid LC-MS/MS method was developed and validated for the quantification of epalrestat, an aldose reductase inhibitor for the treatment of diabetic neuropathy. Following protein precipitation epalrestat and IS were eluted with 10mM ammonium acetate and acetonitrile using a rapid gradient program on reverse phase column. Multiple reaction monitoring mode was used to monitor the transitions of m/z 318→58 for epalrestat and m/z 410→348 for the IS. The assay exhibited a linear dynamic range of 2-5,000 ng/mL for epalrestat in rat plasma. Acceptable precision and accuracy were obtained for concentrations over the standard curve range. The within batch accuracy was in the range of 101.3-108.0% with precision in the range of 3.0-12.3%. All the other validation parameters were within the acceptable limits. Validated method was applied to analyze rat plasma samples obtained from a pharmacokinetic study. After oral administration of epalrestat at 10mg/kg to wistar rats (n=3) mean C(max), AUC(0-24) (ngh/mL) and t(1/2) were found to be 4077 ± 1327 ng/mL, 8989 ± 1590 ngh/mL and 2.9 ± 1.4h, respectively. Bioavailability was found to be 90 ± 14% for epalrestat in male wistar rats.

Nirogi R ，Kandikere V ，Ajjala DR ，Bhyrapuneni G ，Muddana NR ... -  《-》

Simultaneous determination of acetylpuerarin and puerarin in rat plasma by liquid chromatography-tandem mass spectrometry: Application to a pharmacokinetic study following intravenous and oral administration.

A rapid and sensitive liquid chromatography-tandem mass spectrometric (LC-MS/MS) method was developed and validated for the simultaneous determination of acetylpuerarin (AP) and its major metabolite puerarin (PUE) in rat plasma using genistein as the internal standard (IS). Plasma samples were pretreated by protein precipitation with a mixture of methanol and acetonitrile. Chromatographic separation was performed on a CAPCELL PAK C18 MGШ column with a mixture of 0.1% formic acid in water and methanol (35:65, v/v) as the mobile phase. The analytes were detected using a tandem mass spectrometer in the positive ionization and multiple-reaction monitoring mode. The ion transition of m/z 669.4→627.3, 417.5→297.6 and 271.3→153.0 was utilized to quantify AP, PUE and the IS, respectively. The calibration curves showed good linearity over the plasma concentration range of 1-2000ng/mL for AP and 2.5-5000ng/mL for PUE. The intra- and inter-day precisions (RSD %) for each analyte were less than 6.91%, and the accuracies ranged from -2.17% to 2.93%. The validated LC-MS/MS method was further successfully applied to a pharmacokinetic study of AP and PUE in rats following intravenous and oral administration.

Sun D ，Xue A ，Wu J ，Zhang B ，Yu J ，Li Q ，Sun C ... -  《-》

Determination of glibenclamide and puerarin in rat plasma by UPLC-MS/MS: application to their pharmacokinetic interaction study.

In the treatment of diabetes mellitus, glibenclamide and puerarin may be co-administered unwittingly or wittingly. An ultra performance liquid chromatography-tandem mass spectrometry method was developed to determine the concentrations of glibenclamide and puerarin in rat plasma for the study of pharmacokinetic interaction between them. Analytes were extracted using liquid-liquid extraction. The separation was achieved on a Waters BEH C18 column using 5 mmol/L ammonium acetate solution (containing 0.1% formic acid) and methanol as mobile phase with a linear gradient program. Electrospray ionization source was applied and operated in the multiple reaction monitoring positive mode. The proposed method was proved simple, specific and reliable. Glibenclamide, Pueraria lobata extract and glibenclamide in combination with P. lobata extract were orally administered to rats, respectively. Pharmacokinetic parameters were estimated by Microsoft Excel software and analyzed by SPSS 12.0 software. Compared with glibenclamide group, pharmacokinetic parameters of glibenclamide in the co-administration group such as area under the curve and mean residence time were increased while clearance was decreased. Pharmacokinetic parameters of puerarin in the co-administration group such as peak concentration and area under the curve were enlarged while clearance and apparent volume of distribution were reduced compared with P. lobata extract group. These changes could enhance drug efficacy, but could also make drug accumulation to increase adverse effects, so it was suggested that the dosage should be adjusted or the drug concentration in plasma should be monitored if glibenclamide and puerarin were co-administered.

Li N ，Deng Y ，Wang D ，Qiao Y ，Li F ... -  《-》

LC-MS/MS method for the determination of a new puerarin derivative and its application in pharmacokinetic studies in rats.

To establish a sensitive and rapid liquid chromatographic-tandem mass spectrometry (LC-MS/MS) method for the quantitative analysis of dehydrated puerarin in rat plasma, and its application for pharmacokinetic studies. A plasma sample was pretreated by one-step protein precipitation by the addition of five volumes of methanol. The chromatographic separation was achieved on a Zorbax SB-C18 column (4.6 mm × 150 mm I.D. 5.0 μm, Agilent, USA) at 40 °C at a flow rate of 0.6 mL·min(-1) by an isocratic elution consisting of 10 mmol·L(-1) ammonium acetate in methanol and water containing 0.1% formic acid in a ratio of 20 : 80 (V/V). Detection was performed on a triple quadrupole mass spectrometer in multiple-reaction monitoring (MRM) mode. An atmospheric pressure chemical ionization (APCI) interface in positive ionization mode was used by monitoring the transitions from m/z 399.1→281.0 (dehydrated puerarin) and m/z 271.0→215.0 (internal standard, IS). Calibration curves were linear in the concentration range from 1.50 to 5400 ng·mL(-1), and the lower limit of quantification (LLOQ) was 1.50 ng·mL(-1) in rat plasma. The accuracy and precision values, which were calculated from three different sets of quality control samples analyzed in sextuplicate on three different days, ranged from 95.73% to 103.18%, and from 4.33% to 7.86%, respectively. The method was successfully applied to assess the pharmacokinetics of dehydrated puerarin after oral administration in rats.

Liu AC ，Zhao LX ，Xing J ，Gao J ，Lou HX ... -  《-》