Pharmacokinetics and Safety of Armodafinil in Chinese Healthy Humans After Multiple-Dose Oral Administration

Armodafinil, the R-enantiomer of modafinil that promotes wakefulness, was studied regarding its pharmacokinetics and safety in healthy Chinese subjects after multiple-dose oral administration (200 mg daily for 7 days). Twelve subjects participated in this single-center, self-contrast study. The plasma concentrations of armodafinil and its metabolites (R-modafinil acid and modafinil sulfone) were measured by ultra-performance liquid chromatography-tandem mass spectrometry, and drug safety was evaluated during the study. The steady-state accumulation ratio of armodafinil was 1.5, and its metabolites also accumulated with ratios of 1.3 and 7.8, respectively. Although the mean steady-state half-life was similar to that after a single dose, the area under the concentration-time curve, maximum plasma concentration, and clearance of armodafinil changed significantly after multiple dosing. The drug was safe with no serious adverse events, yet fever occurred in 6 subjects, which was not reported before. Modafinil sulfone had significant accumulation, implying the need for further study on its central nervous system-activating properties in Chinese patients.