Plasma protein binding of 7-hydroxy-Δ1-tetrahydrocannabinol: an active Δ1-tetrahydrocannabinol metabolite

Abstract 7-Hydroxy-Δ1-tetrahydrocannabinol, which is a pharmacologically and psychologically active metabolite of Δ1-tetrahydrocannabinol in man, has been shown by equilibrium dialysis and ultrafiltration to be bound 94–99% to plasma proteins. Further experiments, using the [14C]labelled compound, with agarose and Polyacrylamide gel electrophoresis and ultracentrifugation suggest that albumin, α1-lipoprotein and, to a minor degree, also β-lipoprotein are involved in the protein binding of 7-hydroxy-Δ1-tetrahydrocannabinol in blood plasma.