Abstract

A sensitive LC-ESI-MS method with a solid-phase extraction was established for the determination of bilobalide, ginkgolide A and ginkgolide B in human plasma; bioavailability and pharmacokinetics of three different Ginkgo biloba L. preparations have been investigated. The preparations used in the present single-dose pharmacokinetic study were different formulations of Ginkgo biloba L. extracts (Geriaforce tincture, new Ginkgo fresh plant extract tablets and EGb 761) with various excipients. The analysis of Ginkgo terpene lactones was performed by LC-MS on a Zorbax SB-C18 column. The mobile phase consisted of water + 0.1% acetic acid and methanol 68/32 (v/v) to 49/51 (v/v) at a flow rate of 200 microL/min. Bilobalide, ginkgolide A and ginkgolide B were monitored using the selected-ion monitoring (SIM) mode at m/z of 325, 453 and 423, respectively.The amounts of the active compounds (terpene lactones) in the administered products were in the low-mg range per dose. The assay method was successfully applied to the study of the pharmacokinetics and bioavailability of bilobalide, ginkgolide A and ginkgolide B in humans. The resulting maximum concentrations (median) of bilobalide, ginkgolide A and ginkgolide B in plasma after administration of the maximum daily dose of the different Ginkgo products were 3.53, 3.62, and 1.38 ng/mL respectively after administration of Geriaforce tincture; 11.68, 7.36, and 4.18 ng/mL, respectively after taking Ginkgo fresh plant extract tablets; and 26.85, 16.44, 9.99 ng/mL, respectively after administration of EGb 761 tablets. These data are relevant to demonstrate relative bioavailabilities of different Ginkgo biloba L. preparations (Geriaforce tincture, new Ginkgo fresh plant extract tablets and EGb 761).