A COMPARISON OF METHODS FOR THE SEPARATION OF [C-11] RO-15-1788 (FLUMAZENIL) FROM ITS METABOLITES IN THE BLOOD OF RABBITS, BABOONS AND HUMANS

The determination of the percentage of unchanged [C-11]Ro 15-1788 with respect to total radioactivity, essential for the pharmacokinetic exploitation of data of blood radioactivity decrease obtained in PET studies, may be carried out with equal results using either an extraction procedure or a TLC method. The analysis of blood samples of various sources (rabbits, baboons, healthy volunteers and anxious patients) and the use of an automatic linear scanner to quantify the radioactive distribution on the TLC plates lead to the conclusion that only [C-11]Ro 15-1788 and its acid metabolite [C-11]Ro 15-3890 and no other radioactive compound are present in blood at detectable concentration.