Objective:To determine the apparent oil-water partition coefficient of oxysophocarpine in n-octanol-water and n-octanol-phosphate buffer system

and to provide reference for the absorption study in vivo.Method: The apparent oil-water partition coefficient for oxysophocarpine was performed by using shaking flask method with HPLC-DAD as separation and detection pathway.Result: The apparent oil-water partition coefficient of oxysophocarpine was log Papp=-0.44 in n-octanol-water system at 37 ℃.In pH 1.2-10.0 phosphate buffer solutions

log Papp was in the range of-0.97——0.25.When pH<4.5

there was no significant effect on it by pH.When pH>4.5

log Papp of oxysophocarpine showed the gradual increasing tendency with the increasing of pH.Conclusion: The methods described in the paper can be used to determine the oil-water partition coefficient of oxysophocarpine accurately

and help to predict the intracoporal process.