The Plasma Protein Binding of Amphetamine, Catecholamines and Related Compounds

The plasma protein binding of amphetamine, phenmetrazine, adrenaline, noradrenaline, dopamine, normetanephrine and metanephrine was studied using equilibrium dialysis with human plasma. The binding of amphetamine and phenmetrazine at 5 × 10 ‐7 M to 5 × 10 ‐5 M was about 20 %. No difference in the binding of amphetamine was found between drug non dependent and tolerant dependent subjects. At physiological concentrations (< 10 ‐6 M) adrenaline was bound to about 20 %, noradrenaline and dopamine to about 13 %. The binding of metanephrine and normetanephrine was of a lower order, i. e. about 5 %. The results are of value for the understanding of the overall pharmacodynamic situation in amphetamine dependence.