Biological properties of a new thiamine derivative, cyclocarbothiamine.

Abstract

Cyclocarbothiamine, a new thiamine derivative obtained by the reaction of thiamine with phosgene, was found to have a number of advantages over thiamine in its biological properties.1. Its thiamine activity was indistinguishable from that of thiamine when examined in vivo with rats and rice-birds.2. Oral administration of cyclocarbothiamine resulted in far higher thiamine contents in the rabbit blood as well as in the liver and kidney of rats. Marked increase was observed also in blood cocarboxylase levels of rabbits.These data indicate that, as against thiamine, cyclocarbothiamine is absorbed from the intestine in large quantities.3. Intravenously injected cyclocarbothiamine similarly brought about higher blood thiamine levels in rabbits than did thiamine and its urinary excretion was delayed.4. Unlike thiamine, cyclocarbothiamine was not decomposed by either thiaminase I of Bacillus thiaminolyticus or thiaminase II of Bacillus aneurinolyticus.