Pharmacokinetics, tissue distribution, and plasma protein binding study of chicoric acid by HPLC-MS/MS.

Chicoric acid is a major active constituent of Echinacea purpurea and has a variety of biological functions. In this study, a liquid chromatography coupled with tandem mass spectrometry (HPLC-MS/MS) approach was developed and validated for the determination of chicoric acid in rat plasma and various tissues using ferulic acid as an internal standard (IS). This method was successfully applied to pharmacokinetics, tissue distribution, and plasma protein binding (PPB) study of chicoric acid in Sprague-Dawley (SD) rats dosed with 50mg/kg by gastric gavage. The pharmacokinetic parameters were determined and showed a half-life (t1/2) of 4.53±1.44h, an apparent volume of mean residual time (MRT) of 18.58±4.43h, and an area under the curve (AUC) of 26.14 mghL(-1). The tissue distribution of chicoric acid in rats after gavage administration showed a decreasing tendency in different tissues (liver>lung>kidney>heart>spleen>brain). The PPB rates in rat plasma, human plasma, and bovine serum albumin were 98.3, 96.9, and 96.6%, respectively. These results provide insight for the further pharmacological investigation of chicoric acid.