Cell experiment:

Freshly isolated human hepatocytes are used in this study. Briefly, hepatocytes are placed in serum-free Williams’ E media containing 0.1 μM dexamethasone, 10 μg/mL gentamicin, 15 mM HEPES, 2 mM L-glutamine, and 1% ITS. Cells are incubated for 10 hr at 37℃ in an atmosphere containing 5% CO2. After recovery, the hepatocytes are treated with media containing CITCO (100 nM), rifampin (10 μM) or vehicle (ethanol), with or without 1-Aminobenzotriazole (ABT) (1 mM) for 72 hr[1].

Animal experiment:

Male Sprague-Dawley rats (0.26 to 0.30 kg, n=3 per treatment) receive an oral dose of 1-Aminobenzotriazole (ABT) (100 mg/kg, 2 mL/kg) 2 h before a single intravenous bolus of procainamide (10 mg/kg, 2 mL/kg). The control group receives only the intravenous bolus of procainamide without 1-Aminobenzotriazole pretreatment. The vehicle for both 1-Aminobenzotriazole and procainamide is 10% dimethylacetamide/90% water (v/v). Rats are fed 4 h after dosing, and serial blood samples are collected at 0.03, 0.17, 0.25, 0.5, 1, 2, 4, and 6 h postdose. Blood samples are centrifuged using tubes containing K3-EDTA as the anticoagulant to obtain plasma. Urine samples are also collected over 24 h postdose. Plasma and urine samples are frozen at -20℃ until analysis[2].

1-Aminobenzotriazole is a nonspecific and irreversible inhibitor of cytochrome P450 (P450).

1-Aminobenzotriazole (ABT) alone significantly increases the expression levels of CYP2B6 in two different hepatocytes (7.3- and 10.8-fold, respectively). Upon co-treatment with 1-Aminobenzotriazole, the induction of CYP2B6 expression by CITCO or rifampin is potentiated: 12.6- and 4.0-fold for CITCO as well as 3.9- and 2.5-fold for rifampin. 1-Aminobenzotriazole has a greater potentiation effect on CITCO than on rifampin. 1-Aminobenzotriazole alone increases the expression levels of CYP3A4 in tow different hepatocytes (by 2.0- and 3.8-fold). Upon co-treatment with 1-Aminobenzotriazole, the effects of CITCO on CYP3A4 expression levels are potentiated by 3.8- and 6.0- fold as compare to cells treated with CITCO alone[1]. 1-Aminobenzotriazole (ABT) (1 mM) shows pronounced (~95%) inhibition of the formation of N-acetylprocainamide compare with the control without 1-Aminobenzotriazole[2].

Oral 1-Aminobenzotriazole (ABT) (100 mg/kg, 2 h predose) decreases the clearance of intravenous procainamide (45%) in rats, accompanied by a decreased N-acetylprocainamide-to-procainamide ratio in urine (0.74 versus 0.21) and plasma (area under the curve ratio 0.59 versus 0.11). The urinary recovery of procainamide increases from 18 to 30%, whereas the recovery of N-acetylprocainamide in urine decreases from 13.3 to 6.5% with 1-Aminobenzotriazole[2]. Pretreatment of rats with 100 mg/kg oral 1-Aminobenzotriazole (ABT) administered 2 hours before a semisolid caloric test meal markedly delays gastric emptying. 1-Aminobenzotriazole also increases stomach weights by 2-fold[3].

References:
[1]. Yang K, et al. Induction of CYP2B6 and CYP3A4 expression by 1-aminobenzotriazole (ABT) in human hepatocytes. Drug Metab Lett. 2010 Aug;4(3):129-33.
[2]. Sun Q, et al. 1-Aminobenzotriazole, a known cytochrome P450 inhibitor, is a substrate and inhibitor of N-acetyltransferase. Drug Metab Dispos. 2011 Sep;39(9):1674-9.
[3]. Stringer RA, et al. 1-Aminobenzotriazole modulates oral drug pharmacokinetics through cytochrome P450 inhibition and delay of gastric emptying in rats. Drug Metab Dispos. 2014 Jul;42(7):1117-24.