Effective Dosing Regimen of 1-Aminobenzotriazole for Inhibition of Antipyrine Clearance in Rats, Dogs, and Monkeys

Abstract

This article is available online at http://dmd.aspetjournals.org ABSTRACT: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 M) 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. ABT1 has been extensively used as a nonspecific inhibitor of cytochromes P450 in animals for mechanistic studies (Mico et al., 1988;Huijzer et al., 1989;Mugford and Tarloff, 1995;Su et al., 1998;Constan et al., 1999;Marczylo and Ioannides, 1999). The method of use of ABT has been quite variable from lab to lab, for example, single versus multiple dosing of animals prior to the test compound, p.o. versus i.v. route of administration, different pretreatment times, and different dose levels. Moreover, the pharmacokinetics of ABT in different species have not been reported. Also there is incomplete information in the literature on the inhibition of P450s by ABT (Knickle and Bend, 1992;Su et al., 1998;Di Re et al., 1999). To provide a guideline for the pretreatment regimen of ABT, 1) single dose oral pharmacokinetic studies were conducted in rats, dogs, and monkeys at several dose levels; 2) in vitro inhibition of various recombinant P450s by ABT was determined; and 3) the effect of selected doses of ABT on the intravenous pharmacokinetics of antipyrine, a probe for measuring efficiency of hepatic oxidative metabolism, was determined. The results from these studies are described in this report. Materials and MethodsABT and antipyrine (AP) were obtained from Sigma-Aldrich (St. Louis, MO). Single oral dose pharmacokinetics of ABT, in 0.5% aqueous methylcellulose, were studied in fasted male Sprague-Dawley rats at 10, 50, and 200 mg/kg (n Ն 3) and in Beagle dogs and Cynomolus m...

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“…S1) resulted in a high blood clearance of 61 mL/min/kg and a half-life of only 1.3 h. Following predosing of rats with the irreversible CYP450 inhibitor, 1-aminobenzotriazole, the clearance reduced to 31 mL/min/kg. Although these results confirmed a contribution of CYP-metabolism to the clearance of OZ277, they also indicated a role for non-CYP mechanisms, as the reduction in clearance with 1-aminobenzotriazole was considerably less than what would be expected for a compound predominantly cleared through CYP450 metabolism (20,21).…”

In Vitro–In Vivo Correlation for Low-Clearance Compounds Using Hepatocyte Relay Method

“…The in vivo clearance values were carefully selected from the literature using only i.v. beagle dog PK parameters (Suh et al, 1997;Kimura et al, 1999;Bayliss and Cross, 2000;Balani et al, 2002;Granero and Amidon, 2008;Neirinckx et al, 2011) (with the exception of one report on ketoprofen being mongrel dog, but it showed no significant difference from beagle dog data). All compounds showed good correlation between dog hepatocyte relay assay and in vivo intrinsic clearance values ( Fig.…”

“…1, the rat, dog, and human hepatocyte relay method gave good prediction of in vivo intrinsic clearance [additional human data were collected during this study and added to the previously published set (Di et al, 2012)]. For most compounds, 9.0 6 3.9 1.2 Antipyrine 14 (Balani et al, 2002) 14 6 1.4 1.0 Naproxen 22 c (Suh et al, 1997) 20 6 3.0 1.1 (6)-Ketoprofen 48 -114 d (Granero and Amidon, 2008;Neirinckx et al, 2011) 24 6 1.2 2.0-4.7 e a F u and R b values were from the literature (Berry et al, 2011) or in-house data. b The equation CL iv = oral dose (Dose PO )/oral area under the curve (AUC PO ) Â F was used to derive i.v.…”

THE EFFECT OF CIMETIDINE ON DEXTROMETHORPHAN O-DEMETHYLASE ACTIVITY OF HUMAN LIVER MICROSOMES AND RECOMBINANT CYP2D6

“…In control experiments, 1-aminobenzotriazole was used as a mechanism-based inactivator of both human liver microsomal and recombinant CYP2D6 (Balani et al, 2002). After preincubation of pooled human liver microsomes with 20 M ABT and NADPH, a 34% loss in activity was observed, whereas preincubation of a 4 M concentration of the inactivator with the recombinant enzyme resulted in a 52% decrease in activity (Fig.…”