摘要:The factors that causes age-dependent changes in phenytoin tissue and serum protein binding in rats were studied. It was confirmed that the age-dependent changes in the concentration of tissue constituents to which phenytoin bound mainly governed the change in phenytoin tissue binding. The concentration of the tissue constituents, protein and phospholipid, was changed by the water content in tissues in the growth process of rats. The increase in serum protein binding of phenytoin in the growth process of rats was caused by changes in both serum albumin concentration and binding parameters of phenytoin to serum albumin. The changes in binding parameters of phenytoin to serum albumin were led by those in the molar rations of free fatty acids to albumin.