N-Methylpyridoxamine: Novel canine vitamin B6 urine metabolite

The urine of canines given daily dosage of pyridoxamine revealed an unidentified metabolite hypothesized to be N-methylpyridoxamine. Its identity was established by synthesis of N-methylpyridoxamine and comparison to the canine metabolite by HPLC. The synthetic compound was confirmed by IR, NMR, UV-vis, and emission spectroscopy. Although N-methylpyridoxamine is a significant canine pyridoxamine metabolite, relevance to vitamin B6 metabolism in other species, including humans, is not yet determined.