Simultaneous Determination of Four Main Isosteroidal Alkaloids of Bulbus Fritillariae Cirrhosae in Rat Plasma by LC–MS–MS

Abstract

A simple, sensitive and selective liquid chromatography–tandem mass spectrometry (LC–MS–MS) method was developed for simultaneous quantitation of four isosteroidal alkaloids (peimine, peiminine, peimisine, and delavine) in rat plasma. Carbamazepine was selected as internal standard (IS). The LC–MS–MS system coupled with an electrospray ionization (ESI) source was performed in the multiple reaction monitoring (MRM) mode. The transitions of the isosteroidal alkaloids executed as following: m/z 432.4 → 414.4 for peimine, m/z 430.5 → 412.4 for peiminine, m/z 428.4 → 114.2 for peimisine, m/z 416.5 → 105.2 for delavine, and m/z 237.2 → 194.2 for carbamazepine (IS). Sample preparation was performed with liquid–liquid extraction using ethyl acetate after carbamazepine (IS) spiked. The separation was performed on a Welch C18 column (3.5 μm, 2.1 × 100 mm), and a gradient elution of methanol and 5 mmol L⁻¹ ammonium acetate in 0.1 % formic acid aqueous solution was used. The retention time was less than 8.0 min. Linearity was obtained over the concentration range of 0.2–200 ng mL⁻¹ for peimine and peiminine, and 1.0–200 ng mL⁻¹ for peimisine and delavine. The method was linear for all analytes with correlation coefficients >0.995. The intra-day and inter-day accuracy and precision of the assay were acceptable. This method has been successfully applied to the pharmacokinetic study of Bulbus Fritillariae Cirrhosae extract after oral administration to rats.