Determination of isoorientin levels in rat plasma after oral administration of Vaccinum bracteatum Thunb. methanol extract by high‐performance liquid chromatography‐tandem mass spectrometry

Abstract

A simple, sensitive and rapid liquid chromatography tandem mass spectrometry method (LC-MS/MS) was developed and validated for the determination of plasma isoorientin levels in rats. After simple protein precipitation using methanol, chromatographic analysis was performed using a Synergi 4μ polar-RP 80A column (150 × 2.0 mm, 4μm) under isocratic conditions and a mobile phase consisting of 0.1% formic acid in water and methanol (80:20, v/v) at a flow rate of 0.2 mL/min. In positive electrospray ionization mode, the protonated precursor and product ion transitions of isoorientin (m/z 449.0 → 299.1) and of puerarin (the internal standard; m/z 417.1 → 297.1) were acquired by multiple reaction monitoring. Calibration curves obtained for plasma showed good linearity over the concentration range 1-1000 ng/mL. The lower limit of quantification was 1 ng/mL. Intra- and inter-day precisions were within 8.8% relative standard deviation. Accuracies ranged from 92.1 and 109.7%. The isoorientin stability in rat plasma under typical handling/storage conditions also found to be acceptable. The developed method was applied successfully to a pharmacokinetic study of isoorientin orally administered as the methanol extract of Vaccinium bracteatum Thunb. or administered as pure isoorientin.

Determination of KD025 (SLx-2119), a Selective ROCK2 Inhibitor, in Rat Plasma by High-Performance Liquid Chromatography-Tandem Mass Spectrometry and Its Pharmacokinetic Application

“…The LOD was determined using the equation LOD = 3.3σ/m, where σ is the standard deviation of the intercept of the regression line, and m is the slope of the calibration curve [40,41]. It was also experimentally determined using the criterion of a signal-to-noise ratio of 3:1.…”

“…The acceptable criteria for precision and accuracy were set within a deviation of ±15%, except at the LLOQ, where the criteria were set at ± 20% [39]. A calibration curve with a correlation coefficient (R) of not less than 0.990 was considered acceptable for the linearity [41].…”

“…The matrix effect was evaluated using three sources of blank plasma matrix to determine whether the endogenous components of plasma affect the ionization of KD025 and IS. Post-deproteinization samples and methanol solutions of KD025 at equivalence concentrations were compared in terms of peak areas [41,42].…”

“…Freeze-thaw stability was tested over three repeated cycles, in which QC samples were frozen at −20 • C and then thawed at room temperature. Peak area ratio changes of < 15% between stored and freshly prepared samples were considered as the criteria for the stability of samples [41].…”

“…The plasma peak concentration (C max ) and time to reach C max (T max ) were directly determined from each individual plasma concentration-time profile. Other pharmacokinetic parameters were calculated using WinNonlin®3.1 software (Pharsight, Cary, NC, USA) by a non-compartmental method, as described previously [41,43]. Results are presented as means ± standard deviations.…”