Determination of metabolic profile of novel triethylamine containing thiophene S006-830 in rat, rabbit, dog and human liver microsomes.

Abstract

CDRI S006-830 is a potent triethylamine containing thiophene antitubercular compound of the Central Drug Research Institute, India. The present study aimed to conduct comprehensive metabolic investigations of CDRI S006-830 to corroborate its preclinical investigations. Preliminary metabolic investigations were performed to assess the metabolic stability, enzyme kinetics, reaction phenotyping, and metabolite identification of CDRI S006-830 in rat, rabbit, dog, and human liver microsomes using liquid chromatography with mass spectrometry. The observed in vitro t1/2 and Clint values were 9.9 ± 1.29, 4.5 ± 0.52, 4.5 ± 0.86, 17 ± 5.21 min and 69.60 ± 8.37, 152.0 ± 17.26, 152.34 ± 27.63, 33.62 ± 21.04 μL/min/mg in rat, rabbit, dog and human liver microsomes respectively. These observations suggested that CDRI S006-830 rapidly metabolized in the presence of NADPH in liver microsomes of rat, rabbit and dog while moderately metabolized in human liver microsomes. It was observed that CDRI S006-830 exhibited monophasic Michaelis-Menten kinetics. The metabolism of CDRI S006-830 was primarily mediated by CYP3A4 and was deduced by CYP reaction phenotyping with known potent inhibitors. CYP3A4 involvement was also confirmed by cDNA-expressed recombinant human isozyme activity with different CYPs. Four major phase-I metabolites of S006-830, (M-1 to M-4) were detected in rat, rabbit, dog (except M4) and human liver microsomes.