Development and Validation of UPLC-MS/MS Method for Determination of Enasidenib in Rat Plasma and Its Pharmacokinetic Application.

In our research, a straightforward UPLC-MS/MS method, with diazepam as the internal standard (IS), was proposed and acknowledged to determine the concentrations of enasidenib in rat plasma. When preparing the sample, we used acetonitrile for protein precipitation. The gradient elution method was used, and the mobile phase was acetonitrile and 0.1% formic acid. Diazepam was used as the IS. We used the Acquity UPLC BEH C18 column to separate enasidenib and IS. Under the positive ion electrospray ionization (ESI) source conditions, the mass transfer pairs of enasidenib were monitored by multiple reaction monitoring (MRM) to be m/z 474.2 ⟶ 456.1 and m/z 474.2 ⟶ 267.0, and the IS mass transfer pairs were m/z 285.0 ⟶ 154.0. Enasidenib had good linearity (r 2 = 0.9985) in the concentration range of 1.0-1000 ng/mL. Besides, the values of intraday and interday precision were 2.25-8.40% and 3.94-5.46%, respectively, and the range of the accuracy values varied from -1.44 to 2.34%. Matrix effect, extraction recovery, and stability were compliant with FDA approval guidelines in terms of bioanalytical method validation. We had established a new method that had been applied to the pharmacokinetic study of enasidenib in rats.

Simultaneous determination of six components of Danzhi Xiaoyao Pill in beagle plasma by HPLC-MS/MS and a study of pharmacokinetic of paeoniflorin and geniposide after single-dose administration.

This study was to develop a reliable and simple high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) to detect paeoniflorin, geniposide, saikosaponin b2, liquiritin, paeonol and atractylenolide Ⅲ in beagle plasma and to study pharmacokinetic of paeoniflorin and geniposide after single-dose administration of Danzhi Xiaoyao Pill (DZXY). Chromatographic separation was performed using an Agilent C18 column, and multiple reaction monitoring (MRM) mode was used. A gradient elution procedure was used with solvent A (acetonitrile) and solvent B (0.1 % formic acid-water) as mobile phases. The elution procedure was as follows: 85 % B-30 % B (0-7 min) and 30 % B-30 % B (7.1-8 min). The flow rate was 0.3 mL/min. The column temperature was 40 ℃, and the injection volume was 10 µL. The main analytical parameters of paeoniflorin, geniposide, saikosaponin b2, liquiritin, paeonol and atractylenolide Ⅲ were m/z 525→449, m/z 433→224, m/z 780→617, m/z 417→254, m/z 167→43 and m/z 249→231, respectively. Ethyl acetate was used to extract the analytes in the plasma. Standard calibration curves of six analytes showed satisfactory linearity (r2≥0.99 2) within the determined ranges. The lower limits of quantification were 0.5 ng/mL for paeoniflorin and liquiritin, 2.5 ng/mL for geniposide and saikosaponin b2 and 1.0 ng/mL for atractylenolide Ⅲ and paeonol, respectively. The intra-day and inter-day precision (RSD %) were all below 6.94 %, and the intra-day and inter-day accuracy (RE %) were within ± 6.10 %. The recovery and ME of six analytes were 85.99 %-98.10 % and 95.78%-108.06%, respectively. Additionally, the method we established in this experiment can be successfully used to study the pharmacokinetics of paeoniflorin and geniposide in beagle plasma.