Simultaneous quantification of 6,7-di-hydroxyligustilide and gastrodin in rat plasma by LC-MS: application to pharmacokinetic study of tianshu capsule

A LC-MS method was developed and validated for simultaneous determination of 6, 7-di-hydroxyligustilide and gastrodin in rat plasma, and which was subsequently applied in the pharmacokinetic analysis of an administration of a Chinese herbal extract containing Chuanxiong Rhizoma and Gastrodia Elata Rhizome, i.e. TianShu capsule against migraine. The analytes were separated on a Kromasil C18 column with a gradient elution program and detected without interference in the selected ion monitoring mode with positive electrospray ionization. The linear range was 0.010-10.0 μg/mL for 6,7-di-hydroxyligustilide and 0.025-25.0 μg/mL for gastrodin with the limit of quantitation of 0.01 and 0.025 μg/mL, respectively. The intra-day and inter-day precisions for the entire validation were less than14.7 % of RSD. The pharmacokinetic parameters indicated that 6, 7-di-hydroxyligustilide and gastrodin are absorbed rapidly and reached a maximum concentration within one hour, which was consistent with the clinical requirements for the rapid relieving the symptoms of migraine. Colegio de Farmacéuticos de la Provincia de Buenos Aires