[Pharmacokinetics of 6-mercaptopurine in rats during postnatal development].

It was shown that 6-MP pharmacokinetics in rats was age-dependent. The distribution processes were mainly influenced by age of animals. 6-MP total distribution volume (VD) increased from 26.4 ml in 2 week old animals to 60.2 ml and 55.5 ml in 4-week-old and adult rats, respectively. However, the relative volume of distribution (delta, per cent of body weight) decreased from 1019 ml/kg in 2 week old rats to 317 ml/kg in adult rats. Similar relationships between total body clearance and the age of animals were observed. One may suspect that the changes in the distribution processes are connected both with the increased extracellular water content and the changed protein binding in young animals.