抄録
By means of mass fragmentography using the isotope dilution method, the measurement of the plasma concentration of aminopyrine (AM) and its metabolites was performed successfully. It was clarified from the plasma concentration-time curve that the individual differences were observed in two processes which are demethylation of AM to 4-monomethylaminoantipyrine (MAA) or MAA to 4-aminoantipyrine (AA) and acetylation of AA to 4-acetylaminoantipyrine. Furthermore, a quantitative correlation between the plasma concentration and the amount of urinary excretion was discussed.
