LC–MS/MS determination of helicid in human plasma and its application in pharmacokinetic studies

Helicid is a traditional Chinese medicine used to treat headache and insomnia with definite effects. To facilitate pharmacokinetic studies of helicid in man, a sensitive and specific LC–MS/MS method for the quantitative detection of helicid in human plasma was developed and validated. The method involved the addition of bergeninum as the internal standard (IS), protein precipitation, HPLC separation, and quantification by MS/MS system using negative electrospray ionization in the multiple reaction monitoring mode (MRM). The precursor → product ion transitions were monitored at m/z 282.8 → 120.9 for helicid and m/z 326.9 → 192.2 for the IS, respectively. The lower limit of quantification (LLOQ) was 0.2 μg/L. The calibration curves for helicid was linear over a concentration range of 0.2–20 μg/L. The intra- and inter-batch analyses of QC samples at 0.4, 2, 20 μg/L indicated good precision (%R.S.D. between 2.69 and 5.47%) and accuracy (between 96.15 and 105.05%). The helicid was stable in human plasma stored at room temperature for at least 24 h, 4 °C for at least 24 h, −20 °C for at least 1 month, and for routine three freeze–thaw cycles. This accurate and specific assay provides a useful method for evaluating the pharmacokinetic profile of helicid in humans.

► An LC–MS/MS assay for the measurement of helicid in human plasma has been established. The method is specific, sensitive, and accurate over a concentration range of 0.2–20 μg/L.
► This method demonstrated a relatively short analysis time and the good precision, selectivity, recovery and stability. The lowest standards in the calibration curves of plasma, whose signal-to-noise ratio (S/N) were larger than 10, were 0.2 μg/L, which is the lowest detection level reported so far.
► The developed method was fully validated and successfully applied to the human pharmacokinetics studies following a single oral dose of 100 mg helicid.