To clarify the difference in the bioavailability of vitamin B_1(B_1) and vitamin B_2 (B_2) after oral administration of tablets containing thiamin tetrahydrofurfuryl disulfide (TTFDT) or multivitamin tablets (MVT), two tablets of each preparation were given to six healthy male subjects with age of 20-23 years old. In a single dose experiment of trial I, the peak blood B_1 concentration occurred at 2hrs after administration of 10mg of thiamin tetrahydrofurfuryl disulfide (TTFD) and approximately 16-17% of the dose was excreted into the urine in 24hrs. No differences were observed in the blood concentration-time profiles and in the urinary excretion between TTFDT and MVT. The peak blood concentration of B_2 was also reached at 2hrs after administration of 7mg of riboflavin and approximately 11% of the dose was excreted into the urine in 24hrs. After repeated oral administration of 10mg of TTFD and 7mg of riboflavin per day, in a form of a multivitamin tablet, for 1 week in trial II, B_1 and B_2 concentrations in blood and urine were also determined. B_1 concentrations of 7th administration at each point have shown higher values than those of 1st administration, while the concentration-time patterns have shown little difference between the 1st and the 7th administrations. And daily amounts of B_1 excreted have also been increased with the repeated administrations. On the other hand, the peak blood B_2 concentration has not changed greatly between the 1st and the 7th day administrations, although B_2 concentrations of each starting, point have risen with repeated administrations. However, daily amounts of riboflavin have also increased gradually.
