Application of a liquid chromatography–tandem mass spectrometry method to the pharmacokinetics, tissue distribution and excretion studies of Dactylicapnos scandens in rats

The herbal ingredients of isocorydine and protopine were isolated from Dactylicapnos scandens. This study was aimed at developing a liquid chromatography–electrospray ionization-tandem mass spectrometry (LC–ESI-MS/MS) method to quantify isocorydine and protopine in rat plasma and tissues for pharmacokinetic, tissue distribution and excretion studies. Biological samples were processed with ethyl acetate extraction, and corydaline was chosen as the internal standard (IS). The analytes were separated by a C18 column and detected with a triple quadrupole mass spectrometer using positive ion ESI in the multiple reaction monitoring (MRM) mode. The MS/MS ion transitions monitored were m/z 342.0 → 278.9 for isocorydine, 354.1 → 188.0 for protopine and 370.0 → 192.0 for IS, respectively. Excellent linearity was observed over the concentration range between 10 and 3000 ng/mL for isocorydine and 10–300 ng/mL for protopine. The lower limit of quantification (LLOQ) was 10 ng/mL for both isocorydine and protopine. This novel method was rapid, accurate, high sensitive and high selective. It was successfully applied to the pharmacokinetic, tissue distribution and excretion studies of D. scandens. These preclinical data of D. scandens would be useful for the clinical reference.