Application of a simple and rapid LC-MS/MS method for determination of danshensu in human plasma for an oral pharmacokinetic study of Danshen granules in Chinese healthy subjects

A simple and rapid liquid chromatography-electrospray ionization-tandem mass spectrometry method is developed and validated for the determination of danshensu in plasma of Chinese healthy subjects after oral administration of Danshen granules. After liquid-liquid extraction with ethyl acetate, danshensu and chloroamphenicol (internal standard, IS) were separated on an Agilent Zorbax XDB-C-18 column using a gradient mobile phase consisting of water (0.1% formic acid)-acetonitrile (0.1% formic acid) at a flow rate of 0.45 mL min(-1). The detection was performed in multiple reaction monitoring mode, using the transitions of m/z 196.9 -> 134.8 and m/z 320.9 -> 151.9 for danshensu and chloroamphenicol, respectively. The method was linear over the range of 0.50-500 ng mL(-1) using only 100 mu L of plasma and the lower limit of quantification was 0.50 ng mL(-1). The intra- day and inter-day precisions (% RSD) were all less than 15% and the accuracies (% RE) were within the range of +/- 15%, and recoveries were between 85.0% and 115%. The validated method was successfully applied to an explorative pharmacokinetic study of danshensu in Chinese healthy subjects after oral administration of Danshen granules. After oral administration, T-max and C-max values of danshensu were found to be 0.83 +/- 0.13 h and 257 +/- 73.8 ng mL(-1), respectively. Plasma concentrations declined with t(1/2Z) of 1.65 +/- 0.35 h.