Figure 5.

Proposed human hepatic metabolic pathway of AH-7921 with metabolite identification; ambiguous assignments of functional groups are shown as Markush structures. [M4] is the proposed di-hydroxylated and demethylated metabolite that generated the artifact M4. For M12, both N-O-glucuronide or N-glucuronide structures are possible. M13, the di-demethylated hydroxylamine metabolite found in hydrolyzed authentic urine, is the precursor of M12, identified as “c” in the urine case specimen and shown in parentheses as it was not identified after hepatocyte incubation