Simultaneous determination of tanshinone I, dihydrotanshinone I, tanshinone IIA and cryptotanshinone in rat plasma by liquid chromatography - Tandem mass spectrometry: Application to a pharmacokinetic study of a standardized fraction of Salvia miltiorrhiza, PF2401-SF

A rapid, sensitive and selective liquid chromatography-tandem mass spectrometric (LC-MS/MS) method for the Simultaneous determination of tanshinone I, dihydrotanshinone I, tanshinone IIA and cryptotanshinone, the active components of Salvia miltiorrhiza in rat plasma, was developed. After liquid-liquid extraction with tariquidar as an internal standard, tanshinone I, dihydrotanshinone I, tanshinone IIA and cryptotanshinone were eluted from an Atlantis dC₁₈ column within 5 min with a mixture of methanol and ammonium formate (10 mM, pH 6.5; 85:15, v/ v). The analytes were detected by an electrospray ionization tandem mass spectrometry in the selected reaction monitoring (SRM) mode. The standard curves were linear (r = 0.999) over the concentration range of 0.25-80 ng/mL for tanshinone I, dihydrotanshinone I, tanshinone IIA and cryptotanshinone in rat plasma. The coefficients of variation and the relative errors of tanshinone I, dihydrotanshinone I, tanshinone IIA and cryptotanshinone for intra- and inter-assay at four quality control (QC) concentrations were 1.1-5.1% and -4.0-6.0%, respectively. The lower limit of quantification for tanshinone I, dihydrotanshinone I, tanshinone IIA and cryptotanshinone was 0.25 ng/mL from 100 μL of plasma. This method was successfully applied to the pharmacokinetic study of tanshinone I, dihydrotanshinone I, tanshinone IIA and cryptotanshinone after oral administration of PF2401-SF, the standardized fraction of Salvia miltiorrhiza enriched with tanshinone I, dihydrotanshinone I, tanshinone IIA and cryptotanshinone to male Sprague-Dawley rats.