Simple, sensitive and rapid HPLC-MS/MS method for the determination of cepharanthine in human plasma.

A rapid, sensitive and specific method for the determination of cepharanthine in human plasma using high performance liquid chromatography coupled with tandem mass spectrometry (HPLC-MS/MS) was described. Cepharanthine and the internal standard (I.S.), telmisartan, were extracted from human plasma by methanol to precipitate the protein. A centrifuged upper layer was then evaporated and reconstituted with 100μL methanol. Chromatographic separation was performed on an AGILENT XDB-C(8) column (150mm×2.1mm, 5.0μm, Agilent, USA) using a gradient mobile phase with 1mmol/L ammonium acetate in water with 0.05% formic acid and methanol. Detection and quantitation was performed by MS/MS using electrospray ionization (ESI) and multiple reaction monitoring (MRM) in the positive ion mode. The most intense [M+H](+) MRM transition of cepharanthine at m/z 607.3→365.3 was used for quantitation and the transition at m/z 515.5→276.4 was used to monitor telmisartan. The calibration curve was linear within the concentration range of 0.5-200.0ng/mL (r=0.9994). The limit of quantification (LOQ) was 0.5ng/mL. The extraction recovery was above 81.1%. The accuracy was higher than 92.3%. The intra- and inter-day precisions were less than 9.66%. The method was accurate, sensitive and simple and was successfully applied to a pharmacokinetic study after single intravenous administration of 50mg cepharanthine in 12 healthy Chinese volunteers.