Abstract: Aim To study the pharmacokinetics of acetaminophen (Ace) in healthy volunteers and total recovery of its metabolites in urine. Methods 1.0 g Ace was administrated o rally in 6 fasted healthy males; saliva and 24 h urine were collected regularly for the determination of Ace, glucuronide-Ace (GA) and sulfate-Ace (SA) levels by using HPLC. Results Ace in saliva showed that t_1/2 was (2.50 ± 0.29) h, CL was (10.3 ±1.6) L·h^-1, k was (0.28 ±0.03), AUC was (98.9 ±16.7) μg·h·ml^-1, V_d was (44.4 ±16.5) L; GA and SA in 24 h urine and in total recovery were (3.4 ±0.7) %, (37.5 ± 10.2) %, (24.5 ±15.5) % and (70.4 ±7.7) % respectively. Conclusions Compared with those reported by researchers in western countries, t_1/2 of Ace prolonged 25 % and total elimination was only 50 % of theirs. It seemed that low hepatic glucuronide metabolism might be an important facto r for prolongation of t_1/2 of Ace.

Key words: acetaminaphen, glucuronide-Ace, sulfate-Ace, HPLC, pharmacokinetics