Identification of urinary metabolites of pyrilamine after oral administration to man

1. The metabolism of pyrilamine, 2-[4-methoxybenzyl-(2-dimethylaminoethyl) amino] pyridine, was studied in adult male volunteers after a single oral dose of 50 mg. 2. Solvent extracts of urine obtained with or without enzyme hydrolysis were analysed by gc/ms after derivatization with MSTFA/TMSCI (N-methyl-N-trimethylsilyl-trifluoroacetamide/trimethyl chlorosilane). The structure of metabolites were determined based on EI mass spectra and confirmed with those of authentic standards. 3. Conjugated metabolites identified in the urine were pyrilamine, O-desmethylpyrilamine, and ring hydroxylated derivatives of pyrilamine. O-desmethylpyrilamine was also detected in low abundance as a free form. 4. These metabolites observed in human urine were quite different from those previously reported in rat.