METABOLISM OF THE PET LIGAND [C-11] SCH-23390 - IDENTIFICATION OF 2 RADIOLABELED METABOLITES WITH HPLC

[C-11]SCH 23390 is a radioligand used for PET determination of the D-1-dopamine receptor in the living human brain. An HPLC procedure was developed for analysis of [C-11]SCH 23390 and its radiolabelled metabolites in plasma after injection of the radioligand into human subjects in relation to PET studies. After i.v. injection [C-11]SCH 23390 rapidly declined from plasma, about 50 per cent of the radioligand remaining unchanged after 4 min and about 10 per cent after 40 min. The decline followed a biexponential time course. Two of the probable metabolites, the O-sulphate and the O-glucuronide of SCH 23390 were synthesized and characterized. Two radioactive substances in plasma co-migrated with these reference compounds.