The metabolism of 4-bromoaniline in the bile-cannulated rat: application of ICPMS ((79/81)Br), HPLC-ICPMS & HPLC-oaTOFMS.

An excretion balance study was performed following i.p. administration of 4-bromoaniline (50 mg kg(-1)) to bile-cannulated rats, using bromine-detected (Br-79/81) ICPMS for quantification. Approximately 90% of the dose was recovered in urine (68.9 +/- 3.6%) and bile (21.4 +/- 1.4%) by 48 h post-administration. HPLC-ICPMS (Br-79/81) was used to selectively detect and profile the major urinary and biliary-excreted metabolites and determined that the 0-12 h urine contained at least 21 brominated metabolites with 19 bromine-containing peaks observed in the 6-12 h bile samples. The urinary and biliary metabolites were subsequently profiled using HPLC-oaTOFMS. By exploiting the distinctive bromine isotope pattern ca. 60 brominated metabolites were detected in the urine in negative electrospray ionisation (ESI) mode while bile contained ca. 21. While a large number of bromine-containing metabolites were detected, the profiles were dominated by a few major components with the bulk of the 4-bromoaniline-related material in urine accounted for by 4-bromoanaline O-sulfate (similar to 75% of the total by ICPMS, 84% by TOFMS). In bile a hydroxylated N-acetyl compound was the major metabolite detected, forming some similar to 65% of the 4-bromoaniline-related material by ICPMS (37% by TOFMS).