Objective       To study the pharmacokinetic behavior and bioavailability of evodiamine nanocomplex in rats.       Methods        Evodiamine nanocomplex was prepared by solvent evaporation method

and its loading efficiency

particle size and zeta potential were investigated by RP-HPLC and dynamic laser light scattering. Rats were administrated with (i. g.) evodiamine solution and evodiamine nanocomplex (500 mg/kg)

respectively. Blood samples were collected from eye socket

and evodiamine in blood plasma was extracted by liquid-liquid extraction and determined by RP-HPLC using honokiol as the internal standard (IS). Compartmental pharmacokinetics was analyzed by DAS software.       Results      The loading efficiency

particle size and zeta potential of evodiamine nanocomplex were (24.26±0.97)%

248.8 nm and -28.61 mV

respectively. Mean plasma concentration-time curve of evodiamine after oral administration of evodiamine nanocomplex and evodiamine solution in rats were both in accordance with open two-compartment mode. The bioavailability of evodiamine after oral administration of evodiamine nanocomplex was 2.16 times higher than that of evodiamine solution.       Conclusion      Evodiamine nanocomplex is successfully prepared by solvent evaporation method. The developed HPLC method is suitable for the determination of evodiamine in rat blood plasma. The bioavailability of evodiamine in rats increases remarkably after oral administration of evodiamine nanocomplex as compared with that of evodiamine solution.