Technetium-99m amino acid chelates: correlation of their physico-chemical and physiological parameters. Part I

Ten alpha-aminocarboxylic acids were chelated with 99mTc and purified by sephadex gel chromatography. Their hepatobiliary and renal excretion patterns were determined in rats. It was observed that lipophilicity of these chelates is the only determinant in governing their hepatobiliary excretion, whereas their renal excretion is dependent on some other factors in addition to lipophilicity. Depression of renal excretion in presence of probenecid indicated an interaction of renal tubular transport enzymes with these chelates, which was explained from their hexacoordinated dioxotechnetium (V) chelate structure (II).