The fate and urinary metabolites of thiamine propyl disulfide in rabbit and man

Abstract

The metabolic fate of the propyl mercaptan moiety of thiamine propyl disulfide (TPD) has been studied in rabbit and man for comparison with the previous results obtained with rat. About 70–80 per cent of the radioactivity was excreted into the first 48 hr urine, when 35S-labeled TPD was administered to rabbits by either s.c., i.v. or p.o. route. More than 90 per cent of the urinary metabolites was identified as methyl propyl sulfone (MPS), 2-hydroxypropyl methyl sulfone (2-HPMS), 3-hydroxypropyl methyl sulfone (3-HPMS), methylsulfonyl propionic acid (MSPA) and inorganic sulfate. Following oral administration, inorganic sulfate and MSPA were the predominant products, accounting for about 70 per cent of the urinary metabolites. On the other hand, MPS, 2-HPMS, MSPA and inorganic sulfate were excreted in approximately equal amounts (20–28 per cent) after parenteral administration. Time course changes on metabolites composition were also studied. In the urine of the healthy men who received TPD, was also confirmed the occurrence of MPS, 2-HPMS and 3-HPMS by the isotope dilution method. These results show that there are little species differences among rat, rabbit and man in the metabolism of the propyl mercaptan moiety of the drug.