Abstract: AimTo prepare silybin-phospholipid complex and study its physicochemical properties. To compare the pharmacokinetic characteristics and bioavailability after oral administration of silybin-phospholipid complex and silybin material in rats. MethodsUsing acetone as a reaction medium, silybin and phospholipid were resolved into the medium, when the organic solvent was clear, then removed under vacuum evaporation, silybin-phospholipid complex was obtained. The new complex’s physicochemical properties including DSC, UV, IR were determined. The concentrations of non-conjugated and total silybin after oral administration of silybin-phospholipid complex and silybin material at different time in rats were determined by RP-HPLC. The pharmacokinetic parameters were computed by software program 3P97. ResultsExperiment results showed that silybin and phospholipid in the silybin-phospholipid complex were combined by non-covalent-bond, not forming a new compound and the solubility of silybin-phospholipid complex in water and n-octanol was effectively enhanced. It was found that mean plasma concentration-time curve of silybin after oral administration of silybin-phospholipid complex in rats was in accordance with one-compartment model with first-order absorption. Pharmacokinetic parameters of non-conjugated and total silybin in rats were respectively T_max 10 min and 2 h; C_max 0.11 and 1.08 μg·mL^-1; T_1/2 2.18 and 3.84 h; AUC_0～∞ 1.71 and 12.94 μg·mL^-1·h. However, after oral administration of silybin material, plasma levels of both non-conjugated and total silybin were within the analytical detection limit. ConclusionIt was concluded that after oral administration of silybin-phospholipid complex in rats the bioavailability of silybin increased greatly. This was mainly due to an obvious improvement of the lipophilic property of silybin-phospholipid complex compared with silybin material and an increase in gastrointestinal absorption.