Comparative pharmacokinetics and bioavailability studies of quercetin, kaempferol and isorhamnetin after oral administration of Ginkgo biloba extracts, Ginkgo biloba extract phospholipid complexes and Ginkgo biloba extract solid dispersions in rats.

The aim of this study was to improve the oral bioavailability of Ginkgo biloba extract (GBE) through preparing G. biloba extract phospholipid complexes (GBP) and G. biloba extract solid dispersions (GBS). Firstly we prepared the GBP and GBS and studied their physicochemical properties by differential scanning calorimetry (DSC), powder X-ray diffraction (XRD) and dissolution. Then we studied the pharmacokinetic characteristics and bioavailability in rats. The results showed that the bioavailability of quercetin, kaempferol and isorhamnetin in rats was increased remarkably after oral administration of GBP and GBS comparing with GBE. The bioavailabilities of GBP increased more than that of GBS.