Sijunzi decoction (SJZD) is one of the most well-known traditional Chinese herbal formulations. This study elucidates the pharmacokinetics of SJZD in rat plasma after the administration of a single oral dose of 3 mL/kg using ultra-high-performance liquid chromatography electrospray ionization quadrupole-time of flight mass spectrometry (UHPLC-ESI-Q-TOF/MS) with bergapten as an internal standard. The separation was performed on an Agilent Zorbax Eclipse Plus C column (2.1 × 50 mm, 1.8 μm) by elution with acetonitrile and water (containing 0.1% formic acid) at a flow rate of 0.3 mL/min. Electrospray ionization in positive and negative ion modes was used to quantify six compounds, with monitored ion m/z values of 249.1397 [M + H] and 529.3857 [M + H] for atractylenolide III (ATL-III) and pachymic acid (PA), respectively, and m/z of 1107.6638 [M - H] , 991.5746 [M - H + HCOO] , 821.3714 [M - H] , 469.3315 [M - H] for ginsenoside Rb Re, glycyrrhizic acid (GL), and glycyrrhetinic acid (GA), respectively. The calibration curves for ginsenoside Rb , Re, ATL-III, PA, GL and GA were 0.0015-0.75, 0.001-0.5, 0.0004-0.2, 0.003-0.9, 0.0015-0.3 and 0.001-1.5 μg/mL, respectively. The intra- and inter-day precisions (RSD) were <14.3%. The rapid, sensitive and specific UHPLC-ESI-Q-TOF/MS method developed and validated in this study was successfully applied to the simultaneous determination of the six components of SJZD using rat plasma for pharmacokinetic studies after oral administration.

A simple and sensitive HPLC-MS/MS method was developed and fully validated for simultaneous determination of ginsenoside Rb1, ginsenoside Rg1, paeoniflorin, albiflorin and oxypaeoniflorin in rat plasma. Plasma samples were pretreated with protein precipitation using acetonitrile. The chromatographic separation was carried out on a C column with a gradient mobile phase consisting of acetonitrile and water (containing 0.1% formic acid). All analytes and digoxin (internal stand, IS) were quantitated through electrospray ionization in negative ion multiple reaction monitoring mode. All calibration curves exhibited good linearity (r > 0.9960) over a wide concentration range for all components. The intra-day and inter-day precisions (RSD) at three different levels were all <12.0% and the accuracies (RE) ranging from -6.1 to 6.2%. The extraction recoveries of the five compounds ranged from 89.2 to 97.1%. The validated method was successfully applied in a comparative pharmacokinetic study of Wen-Yang-Huo-Xue soft capsule (WYHXSC) in rats. Compared with single pure component, the exposure of the investigated components, except for oxypaeoniflorin, increased after oral administration of WYHXSC in rats, which suggested a synergistic effects between the herbs in the WYHXSC preparations.

The novel alkaloid, oleracimine, presented remarkable anti-inflammatory bioactivity, and therefore, its pharmacokinetics was investigated in rat plasma after intravenous and oral administration by using a rapid ultra-high-performance liquid chromatography (UHPLC) method with UV detection at 270 nm. The analysis was performed on a shim-pack ODS column (75 mm×2 mm, 1.6 µm particle size, Shimadzu, Japan) column using isocratic elution with a mobile phase consisting of methanol-water (62:38, v/v) within 3 min. The results indicated that oleracimine was rapidly distributed with T max for 11.7 min after oral administration, which presented the double-peak phenomenon in the pharmacokinetic profile with a higher oral absolute bioavailability of 55.1% ± 7.83%.