Assessment of a novel β2-adrenoceptor agonist, trantinterol, for interference with human liver cytochrome P450 enzymes activities

The effect of a novel beta(2)-adrenoceptor agonist, trantinterol on the activities of cytochrome P450 (CYP450) was investigated with human liver microsomes and human cryohepatocytes in order to assess the potential for drug-drug interactions. The ability of trantinterol to inhibit CYP450 activities was evaluated in vitro in human liver microsomes. Trantinterol did not inhibit CYP2C19, CYP2D6, and CYP3A4/5 (IC50 > 100 mu M). It acted as a weak inhibitor of CYP1A2 and CYP2C9 with IC50 of 70.8 and 81.9 mu M, respectively. No time-dependent inhibitions were observed in the present research. To evaluate CYP450 induction, human cryohepatocytes (n = 3) were used and treated once daily for 3 days with trantinterol (0.01, 0.1, and 1 ng/ml), after which CYP450 activities were measured. At concentration of 0.01 ng/ml, which is close to the C-max at maximal recommended doses (50 mu g), trantinterol was about 8% as effective as omeprazole (CYP1A2 inducer) only with donor 2. At concentration of 1 ng/ml, trantinterol was about 3.6 +/- 3.1% as effective as rifampin (CYP3A4/5 inducer). These in vitro results indicated that, at pharmacological relevant concentrations, trantinterol will not produce clinically significant CYP450 inhibition or induction. Crown Copyright (C) 2011 Published by Elsevier Ltd. All rights reserved.