Determination of puerarin in rat plasma by rapid resolution liquid chromatography tandem mass spectrometry in positive ionization mode.

A highly sensitive and specific method of rapid resolution liquid chromatography tandem mass spectrometry (RRLC-MS/MS) in positive ionization mode has been developed and validated for pharmacokinetic study of puerarin in rat plasma. Chromatography was carried out on a Zorbax XDB C18 reversed-phase column using a mobile phase comprising a mixture of methanol and 0.05% acetic acid in water (35:65, v/v) with a flow rate of 0.3 mL/min from 0 min to 5.4 min and then 0.6 mL/min from 5.41 min to 12 min. The mass spectrometer operated in ESI positive ionization mode. Multiple reaction monitoring (MRM) was used to measure puerarin and tectoridin (internal standard). The method was sensitive with a detection limit of 0.33 ng/mL. A good linear response was observed over a range of 10-2000 ng/mL in rat plasma. The inter- and intra-day precision ranged from 2.97% to 7.52% and accuracy from 93.70% to 101.60%. This validated method was applied successfully to a pharmacokinetic study in rat plasma after intravenous administration of puerarin. The main pharmacokinetic parameters were as follows: AUC(0→t) 45.37±13.19 (mgh/L), AUC(0→∞) 47.03±14.78 (mgh/L), MRT 1.03±0.46 (h), T(1/2) 1.31±0.31 (h), V(ss) 0.09±0.02 (L), V(z) 0.17±0.04 (L), Cl 0.10±0.04 (L/h).

Luo CF ，Yuan M ，Chen MS ，Liu SM ，Huang BY ，Liu XW ，Zhu L ... -  《-》

Metabolites of puerarin identified by liquid chromatography tandem mass spectrometry: similar metabolic profiles in liver and intestine of rats.

Puerarin is a major active ingredient of Pueraria radix. Puerarin may exert its medicinal functions in part via its metabolites. In this study, we identified these metabolites to better understand and elucidate puerarin's metabolic pathway. Puerarin was intravenously administered to rats and then metabolites in plasma samples were identified by rapid resolution liquid chromatography electrospray ionization-collision induced dissociation tandem mass spectrometry (RRLC-ESI-CID-MS/MS). Chromatography was conducted on a Zorbax SB C18 column (2.1x100 mm, 1.8 microm) at 30 degrees C, with a gradient mobile phase consisting of 0.05% formic acid and acetonitrile, a flow rate of 0.2 mL min(-1), and a total run time of 14 min. MS/MS acquisition parameters were as follows: positive ionization mode, dry gas: nitrogen, 10 L min(-1), dry temperature: 350 degrees C, nebulizer: 40 psi, capillary: -3500 V, scan range: 250-800. The autoMS, manual, or multiple reaction monitoring mode was selected as required. Two glucuronidated metabolites of puerarin (M1 and M2) were detected. M1 and M2 are presumed to be puerarin-7-O-glucuronide and puerarin-4'-O-glucuronide, respectively, and M2 likely is suspected to be the major metabolite because it represented the predominate peak. Kinetic studies of metabolites demonstrated that M1 and M2 were detected in rat plasma at 5 min after intravenous administration of puerarin, the levels of M1 and M2 then reached their peaks at 10-15 and 15-30 min, respectively. The metabolic profiles were similar in rat liver and intestine investigated by in situ liver and intestine perfusion, indicating that no metabolic regioselectivity of puerarin occurs in the two organs.

Luo CF ，Yuan M ，Chen MS ，Liu SM ，Ji H ... -  《-》

Determination of chamaechromone in rat plasma by liquid chromatography-tandem mass spectrometry: application to pharmacokinetic study.

A rapid, simple and accurate method was developed for the determination of chamaechromone in rat plasma using liquid chromatography tandem mass spectrometry (LC-MS-MS). Rosuvastatin was used as the internal standard. The plasma samples were extracted by liquid-liquid extraction with ethyl acetate. Chromatographic separation was performed on Xbridge™ C(18) column (2.1mm×50mm, 3.5μm) with linear gradient elution using water and methanol, both of which were acidified with 0.1% aqueous formic acid. The flow rate was 0.4mL/min and the total run time was 6min. Detection was performed on a triple-quadrupole tandem mass spectrometer using positive ion mode electrospray ionization (ESI) in the multiple reaction monitoring (MRM) mode. The MS/MS ion transitions monitored were m/z 543.3→198.9 and 481.9→258.3 for chamaechromone and rosuvastatin, respectively. Good linearity was observed over the concentration range of 8-6400ng/mL in 0.1mL of rat plasma. The lowest concentration (8ng/mL) in the calibration curve was estimated as LLOQ with both deviation of accuracy and RSD of precision <20% (n=6). Intra-assay and inter-assay variability were less than 11% in plasma. This method was successfully applied to a pharmacokinetic study of chamaechromone in rats after intravenous (5mg/kg) and oral (100mg/kg) administration. Following oral administration the concentration-time curve of chamaechromone exhibited a biphasic absorption profile. The maximum mean concentration in plasma (C(max), 795.9±14.6ng/L) was achieved at 11.3±0.8h (T(max)) and the area under curve (AUC(0-60)) was 6976.7±1026.9ngh/L. After single intravenously administration of chamaechromone, the essential pharmacokinetic parameters C(max), AUC(0-48) were 4300.7±113.6ng/L and 3672.1±225.4ngh/L, respectively. The result showed that the compound was poorly absorbed with an absolute bioavailability being approximately 8.9%.

Lou Y ，Hu H ，Liu Y ，Yu Q ，Li L ，Ping L ，Yu L ，Jiang H ，Zeng S ... -  《-》

Pharmacokinetics of ergosterol in rats using rapid resolution liquid chromatography-atmospheric pressure chemical ionization multi-stage tandem mass spectrometry and rapid resolution liquid chromatography/tandem mass spectrometry.

Rapid resolution liquid chromatography/tandem multi-stage mass spectrometry (RRLC-MS(n)) and rapid resolution liquid chromatography/tandem mass spectrometry (RRLC/MS/MS) methods were developed for the identification and quantification of ergosterol and its metabolites from rat plasma, urine and faeces. Two metabolites (ERG1 and ERG2) were identified by RRLC/MS(n). The concentrations of the ergosterol were determined by RRLC/MS/MS. The separation was performed on an Agilent Zorbax SB-C18 with the mobile phase consisting of methanol and water (containing 0.1% formic acid). The detection was carried out by means of atmospheric pressure chemical ionization mass spectrometry in positive ion mode with multiple reaction monitoring (MRM). Linear calibration curves were obtained in the concentration range of 7-2000, 6-2000 and 8-7500 ng/mL for plasma, urine and faecal homogenate, respectively. The intra- and inter-day precision values (RSD) were below 10%. The method was applied to the pharmacokinetic properties and elimination pathway of ergosterol in rats.

Zhao YY ，Cheng XL ，Liu R ，Ho CC ，Wei F ，Yan SH ，Lin RC ，Zhang Y ，Sun WJ ... -  《-》

Simultaneous UFLC-ESI-MS/MS determination of piperine and piperlonguminine in rat plasma after oral administration of alkaloids from Piper longum L.: application to pharmacokinetic studies in rats.

The alkaloids from Piper longum L. showed protective effects on Parkinson's disease models in our previous study and piperine and piperlonguminine were the two main constituents in the alkaloids. The present study aimed at developing a rapid, sensitive, and accurate UFLC-ESI-MS/MS method and validating it for the simultaneous determination of piperine and piperlonguminine in rat plasma using terfenadine as the internal standard. The analytes and internal standard (IS) were extracted from rat plasma using a simple protein precipitation by adding methanol/acetonitrile (1:1, v/v). A Phenomenex Gemini 3 u C18 column (20 mm × 2.00 mm, 3 μm) was used to separate the analytes and IS using a gradient mode system with a mobile phase consisting of water with 0.1% formic acid (mobile phase A) and acetonitrile with 0.1% formic acid (mobile phase B) at a flow rate of 0.4 mL/min and an operating column temperature of 25°C. The total analytical run time was 4 min. The detection was performed using the positive ion electrospray ionization (ESI) in multiple reaction monitoring (MRM) mode with transitions at m/z 286.1-201.1 for piperine, m/z 274.0-201.1 for piperlonguminine, and m/z 472.4-436.4 for the IS. The calibration curves were both linear (r>0.995) over a concentration range of 1.0 to 1000 ng/mL; the lower limit of quantification (LLOQ) was 1.0 ng/mL for both piperine and piperlonguminine. The intra-day and inter-day precisions (RSD %) were <12.1%, accuracies ranged from 86.6 to 120%, and recoveries ranged from 90.4 to 108%. The analytes were proven stable in the short-term, long-term, and after three freeze-thaw cycles. The method was successfully applied to pharmacokinetic studies of piperine and piperlonguminine in rats after oral administration of alkaloids from P. longum L.

Liu J ，Bi Y ，Luo R ，Wu X ... -  《-》