Liquid chromatography tandem mass spectrometry pharmacokinetic study of DL-praeruptorin A in rat plasma.

DL-praeruptorin A is a novel drug with valuable apoptosis and inflammation inhibitory effects in cardiac muscle. Previous pharmacokinetic studies of DL-praeruptorin A have had limited success due to its very low plasma concentrations. In this study, we developed and validated a new rapid, sensitive and specific high-performance liquid chromatography electrospray ionization tandem mass spectrometry (HPLC/ESI-MS/MS) method for quantitative analysis of dl-praeruptorin A in rat plasma. DL-Praeruptorin A and diazepam (internal standard) extracted from rat plasma samples with chloroform and analyzed on an XTerra™ RP₁₈ column (150 mm x 4.6 mm i.d., 5 µm) were chromatographically separated within 5.5 min using methanol-water (75:25, v/v; flow rate 1 mL/min) as the mobile phase. DL-praeruptorin A was detected in positive ion mode using multiple reaction monitoring. The method was validated and the specificity, linearity, lower limit of quantitation (LLOQ, 2.5 ng/mL), precision (intra- and inter-day <11.0%), accuracy (90.2-96.3%), recovery (>79.2%) and stability were determined. The correlation coefficient (r²) for the linear range of 2.5-2500.0 ng/mL was >0.999. No matrix effects were observed. The validated method was successfully applied to pharmacokinetic studies of dl-praeruptorin A after intravenous administration to rats. The LLOQ obtained with this method was lower than in previous studies and could be valuable for determination of dl-praeruptorin A in therapeutic drug monitoring and preclinical studies to establish appropriate dose and frequency.