1961 年 81 巻 12 号 p. 1748-1753
In order to examine the biological activity of nicotinic acid N-oxide, biological change of this compound in a rat was examined. Method for determination of nicotinic acid N-oxide has not been established as yet. In the present series of work, a method was devised for determination of nicotinic acid in a supernatant after reduction of the N-oxide group with iron and acetic acid, and removal of iron as a hydroxide by centrifugal precipitation. This method was found to be applicable for determination of nicotinic acid N-oxide in urine.
This method was applied to the determination of urinary excretion after oral administration of 1.0g./kg. of nicotinic acid in a rat and it was found that about 50% of the dose administered was excreted in the urine, of which ca. 20% was in the form of nicotinic acid and 10-20% in the form of nicotinuric acid. Besides these, 1-methyl-6-oxo-1, 6-dihydronicotinamide and a small amount of 1-methylnicotinamide were detected from the urine. In the case of intravenous injection of 100mg./kg. of nicotinic acid N-oxide, almost 50% of this N-oxide, 20-25% of nicotinic acid, and 20-25% of nicotinuric acid were detected from the urine, as well as a trace of 1-methyl-6-oxo-1, 6-dihydronicotinamide and 1-methylnicotinamide.