Pharmacokinetics of single and multiple oral doses of arbidol in healthy Chinese volunteers

Background: Arbidol is licensed in Russia and China for prophylaxis and treatment of influenza A and B. This study was to assess the pharmacokinetics of single and multiple doses of arbidol in healthy Chinese volunteers. Methods: This was a single-center, open-label, two-phase study conducted in 12 subjects. In single-dose phase, subjects were randomized to receive single doses of 0.2, 0.4 and 0.8 g of arbidol in a crossover design with a 7-day washout period between administrations. In the multiple-dose phase, subjects received 0.2 g 3 times a day for 7 days. Serial blood samples were collected at predefined time points. Plasma concentrations were determined with a validated HPLC method. Safety assessments were conducted throughout the study. Results: After administration of single doses of 0.2, 0.4 and 0.8 g, geometric mean estimates for arbidol C-max were 0.70, 1.24, and 2.16 mg/l and the mean of AUC(last) were 3.27, 5.81 and 12.72 mg x h/l, respectively. The AUC(last) and C-max showed dose proportionality. After administration of multiple doses, the mean of Cmax, of arbidol was 0.41 mg/l and the mean accumulation ratio is similar to 1.12. Compared with single-dose phase, arbidol exhibited lower C-max and prolonged plasma concentration profiles. Conclusions: In healthy Chinese subjects, single dosing of arbidol resulted in linear plasma pharmacokinetics. Arbidol exhibited little accumulation with repeated administration. Compared with single doses, multiple oral doses showed somewhat different pharmacokinetics and tissue distribution patterns. Sex did not appear to affect the pharmacokinetic properties of arbidol.