The purpose of this study was to determine the pharmacokinetic characteristics of modafinil and its metabolite modafinil acid in healthy subjects including Chinese Mongolian, Korean and Uyghur, and assess the influence of sex on the pharmacokinetic profiles of modafinil in Chinese subjects. Fifteen healthy Chinese male subjects and fifteen female subjects received 200 mg of modafinil, and the plasma samples were collected at the designed time points. The plasma modafinil concentration was determined by HPLC-UV method. Pharmacokinetic parameters were calculated by DAS software. The pharmacokinetics of modafinil for all of the subjects were in accordance with the two-compartment open model. The mean pharmacokinetic parameters for males and females are as follows： Cmax （4.39±0.53） and （5.86±1.23） μg/mL, AUC0 -∞（65.36±13.93） and （71.74±16.48） μg.h/mL, t1/2β （15.19±3.05） and （14.48±3.95） h for modafinil; Cmax （2.68±0.52） and （3.56±0.57） μg/mL, AUC0 -∞ （29.99±6.05） and （34.53±6.41） μg.h/mL, t1/2β （6.46±1.31） and （5.35±1.46） h for modafinil acid, respectively. Statistical analysis of the pharmacokinetics ofmodafinil and modafmil acid in male and female groups shows that sex has a significant impact on the metabolism of modafinil and modafinil acid. More attention should be paid on the dosage to male or female patients.
