Human urinary excretion of doxifluridine and metabolites during a 5-day chemotherapeutic schedule using fluorine-19 nuclear magnetic resonance spectrometry.

The urinary excretion of doxifluridine (5'dFUrd) and its metabolites was determined during five days of chemotherapy using fluorine-19 nuclear magnetic resonance spectrometry. The daily urinary excretion of 5'dFUrd and its metabolites was high (congruent to 100% of the 5'dFUrd administered) and nearly constant throughout the treatment. By far the major excreted compounds were unchanged 5'dFUrd and alpha-fluoro-beta-alanine which made up respectively congruent to to 40% and congruent to to 50% of the total. Neither accumulation of 5'dFUrd nor significant modifications in its metabolism were observed during the treatment.