Abstract
When 25 or 50 mg of thiothiamine was given parenterally to rats, 2-methyl-4-amino-5-aminomethylpyrimidine (I) was excreted in the 24 hour urine in the amount of less than 0.1 or 0.36 mg while excretion of sulfate in the urine was significantly higher than that of the control animals ; thus, 30〜45% of the given amount of thiothiamine was decomposed into sulfate within 48 hours. When 3-[2'-methyl-4'-aminopyrimidyl(5') ]-methyl-4-methyl-4-hydroxy-5β-hydroxyethylthiazolidine-2-thione (II), presumably an intermediate metabolite of thiothiamine, was given at the amount of 25 or 50 mg to rats, it was also decomposed to sulfate and excreted in the urine to the extent more than 70%, while the excretion of (II) was less than 20% of the given dosage, and excretion of (I) was 0.1 or 0.29 mg in the 24 hour urine. A small amount of (II) was detected in urine when thiothiamine was given. Degradation of thiothiamine to (I) and 2-mercapto-4-methyl-5β-hydroxyethylthiazole in rats was assumed to be such processes through presumed intermediate (II), as shown in the chart 2.
