LC-MS/MS method for determination of seneciphylline and its metabolite, seneciphylline N-oxide in rat plasma, and its application to a rat pharmacokinetic study.

Abstract

A rapid and sensitive ultra-performance liquid chromatography-tandem electrospray ionization mass spectrometry (UPLC-ESI/MS) method was established and validated for simultaneous determination of seneciphylline and its main metabolite in rat plasma. The plasma sample was prepared by simple methanol-mediated precipitation. Chromatographic separation was achieved within 3min by gradient elution using acetonitrile and water containing 0.1% formic acid as mobile phase on a Waters ACQUITY BEH C18 column (100 × 2.1mm, i.d. 1.7 μm). Quantitation was conducted in a positive multiple reaction monitoring mode. The linearity of the method was over the range of 1-1,000 ng/mL, with the lower limit of quantification of 1ng/mL. The intra- and inter-day precision and accuracy, extraction recovery, and matrix effect of analytes were within the acceptable limit. The analytes were stable during the process of sample collection, preparation, and analysis. The validated method was further applied to a pharmacokinetic study of seneciphylline in rats after oral and intravenous administration. The results revealed that seneciphylline was quickly absorbed into plasma (Tmax , 0.23-0.32 h) and reached the maximum concentration of 0.82-1.75 μg/mL after oral administration. Both seneciphylline and seneciphylline N-oxide were eliminated from plasma quickly. The low system exposure (oral bioavailability, 5.43-10.31%) was related to the extensive metabolism in the liver and microflora.