[Determination of levodropropizine and its pharmacokinetics in human plasma using LC/MS/MS].

To develop a rapid and sensitive LC/MS/MS method for the analysis of levodropropizine in plasma and study the pharmacokinetics of levodropropizine in healthy Chinese volunteers. Levodropropizine and zolmitriptan (internal standard, IS) were extracted from plasma samples and chromatographed on a C18 column and detected using a tandem mass spectrometer with a TurboIon Spray ionization interface. Quantitation was performed using multiple reaction monitoring (MRM) of the transitions of the m/z 237 --> m/z 120 for levodropropizine and m/z 288 --> m/z 58 for the IS. The limit of quantification of the method for levodropropizine was 0.25 microg x L(-1). The assay was linear over the concentration range from 0.25 to 500.0 microg x L(-1) and intra- and inter-day precision over this range were < 11.4% with good accuracy. The method is shown to be accurate, and suitable for clinical pharmacokinetic study of levodropropizine.