薬物の金魚ヘの取り込みの速度論(第1報)水層のpH変化およびPolyethylene Glycol 6000,Urea添加によるSalicylic Acid取り込み速度への影響

抄録

This kinetic study dealt with the decrease of salicylic acid concentration in water phase by its uptake into goldfish, and with the effect of different pH of the water phase, addition of polyethylene glycol 6000, and urea derivatives on the uptake. Elimination of salicylic acid in water phase was assumed to be expressed by the following equation : dC₀/dt=k₀C₁-k₁C₀, where C₀, C₁, are the concentration of salicylic acid in water phase and in goldfish, k₀, is the outflux rate constant, and k₁ the influx rate constant. This equation was proved to be consistent with the concentration of salicylic acid with time course. The value of k₁ decreased with increase of pH value in water phase and, therefore, the rate-determining process of salicylic acid flux was thought to be like a lipid membrane. The addition of polyethylene glycol 6000 and urea at 20° had a suppressive and promotive effect on the k₁ respectively. This effect of urea diminished at 10°. The two effects were additive. Both methylurea and dimethylurea were less effective than urea. From the effects of additives and pH in water phase on the k₀, the rate-determining region for the outflux was found to be affected easily by the condition in the external water phase.