Characterisation and biodistribution of two neutral 99mTc(CO)3 complexes with a tridentate ligand

N-(2-Mercapto-propyl)-1,2-phenylenediamine (MPPDA) and N-beta-aminoethylglycine (AEG) were labelled with 99mTc(CO)3(+) to form the neutral complexes 99mTc(CO)3(MPPDA)] and 99mTc(CO)3(AEG)]. Both complexes were formed in excellent yields and their identity was confirmed by LC-MS. In mice, none of the new tracer agents showed brain uptake. (99m)Tc(CO)3(MPPDA)] was trapped mainly in the liver and excreted via the hepatobiliary system, whereas 99mTc(CO)3(AEG)] was excreted rapidly via the kidneys to the urine.