Abstract
Changes in riboflavin concentration in blood and in urine of animals after the administration of riboflavin-2', 3', 4', 5'-tetranicotinate (B_2-Nic) were reported in reference ot those of animals after the administration of free riboflavin. The rate of excretion of riboflavin into urine of animals administered with B_2-Nic was found to be considerably lower than that of animals administered with free riboflavin, suggesting that B_2-Nic was more accumulative in living body than free riboflavin. Moreover, it was found that B_2-Nic was superior to free riboflavin in keeping riboflavin level higher than the normal for a long time. It is, therefore, suggested that this compound could be beneficially used as deposit-type of riboflavin.
