抄録
Biological half-lives (t1/2) of vitamins were calculated by fitting a one- or a two- compartment model after a singe rapid intravenous administration of a multivitamin injection (NK-041) to dogs. The following results were obtained. 1. Half-lives (t1/2) of water soluble vitamins (vitamin B_1, B_2, B_6, B_<12>, C, folic acid and biotin) were short, about 2〜10 minutes, in α-phase and wide ranging, 13 minutes〜5 hours, in β-phase. On the other hand, the half-lives (t1/2) of pantothenic acid and nicotinic acid were 3.99 and 5.67 hours, respectively, which were relatively long among the vitamins tested. 2. The half-life (t1/2) of vitamin A palmitate was the longest, about 26 hours, and the values for vitamin K_1 and E (tocopheryl acetate) were 1.66 and 1.24 hours, respectively. On the other hand, the half-life (t1/2) of vitamin D_2 was short, 16 minutes. Vitamin D_2 might be metabolized rapidly into its 25- hydroxy derivative. However, this metabolite could not be detected in the blood within 240 minutes.
