Determination of Asiatic Acid in Rat Plasma by GC/MS

Method for the determination of the asiaticoside metabolite asiatic acid (target compound) and ursolic acid (internal standard) was developed. The analytes were extracted from alkalized plasma, ion pair extracted with TBAP, further purified and concentrated by SPE method, derived and detected finally by GC/MS. The retention time for asiatic acid and ursolic acid were 15.2 min and 10.4 min. LLOQ of the method was 1.0 ng/mL. Relative recoveries for three concentrations (2.5，10，50 ng/mL) were 101%, 102% and 99.1% respectively, and intra-day RSD were 5.48%, 1.86%, and 1.32% (n=6), inter-day RSD were 9.36%, 5.11% and 1.91% (n=90). The method was sensitive, specific, reliable and suitable for pharmacokinetic study.