TY - JOUR T1 - Effective Dosing Regimen of 1-Aminobenzotriazole for Inhibition of Antipyrine Clearance in Rats, Dogs, and Monkeys JF - Drug Metabolism and Disposition JO - Drug Metab Dispos SP - 1059 LP - 1062 DO - 10.1124/dmd.30.10.1059 VL - 30 IS - 10 AU - Suresh K. Balani AU - Tong Zhu AU - Tian J. Yang AU - Zhi Liu AU - Bing He AU - Frank W. Lee Y1 - 2002/10/01 UR - http://dmd.aspetjournals.org/content/30/10/1059.abstract N2 - 1-Aminobenzotriazole (ABT) has been extensively used as a nonspecific inhibitor of cytochromes P450 (P450s) in animals for mechanistic studies, and antipyrine (AP) has been used as a probe for hepatic oxidative metabolic capacity determination in vivo. The method of use of ABT has been variable from lab to lab due largely to unknown pharmacokinetics of ABT itself and incomplete information on various P450s inhibited. The oral pharmacokinetic profiles of ABT were generated in rats, dogs, and monkeys in the dose range of 5 to 200 mg/kg. The results showed that after single oral doses of 50 mg/kg in rats, and 20 mg/kg in dogs and monkeys, the plasma concentrations were high and were sustained for over 24 h. In vitro, inhibition of various expressed P450s upon 30-min preincubation with ABT (0–500 μM) showed that CYP1A2, 2B6, 2C9, 2C19, 2D6, and 3A4 were inhibited in a dose-dependent manner. The intravenous pharmacokinetics of AP also was affected in a dose-dependent manner in all species, treated 2 h earlier with ABT. Thus, the plasma clearance of AP was inhibited by 88% in rats pretreated with 50 mg/kg ABT and 96% in dogs and 83% in monkeys pretreated with 20 mg/kg ABT. Based on these data in rats, dogs, and monkeys, and the established safety profile of ABT in rats dosed up to 100 mg/kg, a pretreatment at 2 h with a single oral dose of ABT at 100 mg/kg in rats (providing 93% inhibition) and 20 mg/kg in dogs and monkeys effectively inhibited the clearance of the probe compound. The American Society for Pharmacology and Experimental Therapeutics ER -