Simultaneous determination of berberine, palmatine and jatrorrhizine by liquid chromatography–tandem mass spectrometry in rat plasma and its application in a pharmacokinetic study after oral administration of coptis–evodia herb couple

A rapid and sensitive liquid chromatography–tandem mass spectrometry (LC–MS/MS) method was developed to simultaneously determine berberine, palmatine and jatrorrhizine in rat plasma. After mixing with the internal standard (IS) tetrahydropalmatine, plasma samples were pretreated by protein precipitation with acetonitrile–methanol (1:2, v/v). Chromatographic separation was carried out on a C18 column using a mixture of water (containing 0.1% formic acid) and acetonitrile (30:70, v/v) as mobile phase. The detection was performed by selected reaction monitoring (SRM) mode via electrospray ionization (ESI) source operating in the positive ionization mode. The method was linear over the concentration range of 1.0–250.0 ng/mL for all components. The intra- and inter-day precision values were less than 14.6% and the deviations were within ±4.0%. The fully validated LC–MS/MS method has been successfully applied to the pharmacokinetic study of berberine, palmatine and jatrorrhizine in rat plasma after oral administration of coptis–evodia herb couple. Three peaks were observed in both individual and mean plasma–concentration curves of berberine, palmatine and jatrorrhizine, which may be attributed to distribution re-absorption and enterohepatic circulation.