Preparation and evaluation of 3-[125I]iodo-4-aminophentermine as a brain perfusion imaging agent. Comparison with labeled phentermine derivatives.
A radioiodinated derivative of the anorexinergic drug phentermine was synthesized and evaluated as a potential brain imaging agent. Stoichiometric iodination of the intermediate 4-aminophentermine (AmP) gave a mixture of mono and diiodo products, while the radioiodination at the no-carrier-added (NCA) level gave 73% isolated yield of the 3-[125I]iodo-4-aminophentermine with less than 2% of the diiodo derivative. The tissue distribution of the radiochemical in rats showed that it was readily extracted by the brain followed by relatively slow clearance from that organ. However, a comparison with other labeled phentermine derivatives indicated that the total brain uptake, retention and selectivity of the new agent were poorer, probably as a result of the presence of the 4-amino substituent.
D000818:Animals; D001812:Blood-Brain Barrier; D001921:Brain / Q000000981:diagnostic imaging*; D055598:Chemical Phenomena; D002621:Chemistry; D005260:Female; D007202:Indicators and Reagents; D007457:Iodine Radioisotopes; D007700:Kinetics; D008297:Male; D010477:Perfusion; D010645:Phentermine / Q000031:analogs & derivatives* / Q000138:chemical synthesis; D011877:Radionuclide Imaging; D051381:Rats; D011919:Rats, Inbred Strains; D013329:Structure-Activity Relationship; D014018:Tissue Distribution
D007202:Indicators and Reagents; D007457:Iodine Radioisotopes; C047145:3-iodo-4-aminophentermine; D010645:Phentermine