Development of high performance liquid chromatography/electrospray ionization mass spectrometry for assay of ginkgolic acid (15:1) in rat plasma and its application to pharmacokinetics study.

A highly sensitive HPLC-ESI-MS method has been developed and validated for the quantification of ginkgolic acid (15:1) in a small quantity of rat plasma (50μL) using its homologous compound ginkgolic acid (17:1) as an internal standard. GA (15:1) and GA (17:1) were extracted from biological matrix by direct protein precipitation with 5-fold volume of methanol and separated on an Elite hypersil BDS C(18) column (2.1×100mm, 3μm), eluted with acetonitrile:water (92:8, v/v, containing 0.3% glacial acetic acid). Linear range was 8-1000ng/mL with the square regression coefficient (r(2)) of 0.996. The lowest concentration (8ng/mL) in the calibration curve was estimated as LLOQ with both deviation of accuracy and RSD of precision <20% (n=6). The intra- and inter-day precision ranged from 3.6% to 9.9%, and the intra- and inter-day accuracy was between 89.9% and 101.3%. This method was successfully applied to study pharmacokinetics of GA (15:1) in rats after oral administration at a dose of 10mg/kg. GA (15:1) pharmacokinetic parameters C(max), T(max), t(1/2), AUC(0-12h) are 1552.9±241.0ng/mL, 0.9±0.7h, 5.5±2.6h, 3356.0±795.3ngh/mL, respectively.