Development of enantiospecific and chemoselective methods for the determination of praeruptorin A enantiomers and their metabolites in rat plasma using chiral and achiral LC-MS/MS

Abstract

Enantioselective pharmacokinetics and metabolism were revealed for (±)-praeruptorin A (PA), the major bioactive component in Peucedani Radix. In the present study, we deal with the development and validation of two enantioselective methods for enantiospecific determination of PA enantiomers (D-PA/L-PA) and their metabolites, cis-khellactone enantiomers (D-CK/L-CK), rat plasma after intravenous or oral treatment using chiral LC-MS/MS, as well as an achiral LC-MS/MS for simultaneous quantitation of the two hydrolyzed products (L1/L2) after incubation of L-PA in fresh rat plasma. AD-RH and Extend-C₁₈ columns were employed for enantioselective and chemoselective separation, respectively, while the detection was performed on a hybrid triple quadrupole-linear ion trap mass spectrometer with electrospray ionization inlet using a positive selected reaction monitoring mode. The calibration curves of all targeted components showed good linearity (r > 0.992) over the respective concentration ranges (D-PA/L-PA: 1.00–4830 ng mL⁻¹; D-CK/L-CK: 1.50–1630 ng mL⁻¹; L1/L2: 1.10–1080 ng mL⁻¹). The lower limits of quantitation for D-PA/L-PA, D-CK/L-CK and L1/L2 were 1.00/1.00, 1.50/1.50 ng mL⁻¹ and 1.10/1.10 ng mL⁻¹, respectively. For high, medium and low concentration levels of all analytes, the overall intra- and inter-day variations were less than 9.71%, recoveries were in the range 87.7–113%, and matrix effects were between 91.1% and 109%. Above all, the chiral and achiral methods that were developed were satisfactory for the determination of D-PA/L-PA, D-CK/L-CK or L1/L2 in rat plasma.