An HPLC method for the determination and pharmacokinetic study of cinnamic acid in the plasma of rats having taken the traditional Chinese medicinal preparation Ling-Gui-Zhu-Gan decoction.

A high-performance liquid chromatographic method for the determination and pharmacokinetic study of cinnamic acid in the plasma of rats after having been administrated orally with the traditional Chinese medicinal (TCM) preparation Ling-Gui-Zhu-Gan decoction is established. Plasma samples taken from rats are acidified with hydrochloric acid and extracted with ethyl acetate. Separation of the main effective constituent cinnamic acid is accomplished on a C18 stationary phase and a mobile phase of methanol-acetonitrile-2% glacial acetic acid (10:22:70, v/v) with a UV detector setting at 254 nm. After validation, the method is used to take a limited view of pharmacokinetic profiles of the TCM preparation of the Ling-Gui-Zhu-Gan decoction.