UPLC-MS, HPLC-radiometric, and NMR-spectroscopic studies on the metabolic fate of 3-fluoro-[U-¹⁴C]-aniline in the bile-cannulated rat

Abstract

1. A study of the rates and routes of excretion of 3-fluoro-[U-¹⁴C]aniline following intraperitoneal administration to male bile-cannulated rats by liquid scintillation counting (LSC) gave a total recovery of ∼ 90% in the 48 h following dosing, with the majority of the dose being excreted in the urine during the first 24 h (∼ 49%).

2. The total recovery as determined by ¹⁹F-nuclear magnetic resonance (¹⁹F-NMR) was ∼ 49%, with the majority of the dose excreted in the first 24 h (∼ 41%). The comparatively low recovery in comparison to that obtained from LSC was due to matrix effects in bile and a contribution from metabolic defluorination.

3. High-performance liquid chromatography with radiometric profiling of urine and bile revealed a complex pattern of metabolites with the bulk of the dose excreted as a single peak.

4. Ultra-performance liquid chromatography-orthogonal acceleration time of flight mass spectrometry profiling also showed a complex pattern of metabolites, detecting ∼ 21 metabolites of 3-fluoroaniline (3-FA) with six of these detected only in urine and four solely in bile.

5. ¹⁹F-NMR revealed the presence of the parent compound and 15 metabolites in urine collected during the first 24 h after -dosing. The matrix effects of bile on ¹⁹F-NMR spectroscopy made metabolite profiling impractical for this biofluid.

6. The major metabolite of 3-FA was identified as 2-fluoro-4-acetamidophenol-sulfate.

Keywords::

• 3-fluoroaniline
• aniline metabolism
• UPLC-MS
• ¹H-NMR
• ¹⁹F-NMR