Comparative study of 99mTc labeled hepatobiliary agents based on naphthalene and similar ring systems

A series of 99mTc complexes of naphthalene and naphthalene-like ring systems were evaluated pharmacokinetically as hepatobiliary imaging agents and compared to 131I-rose bengal and 99mTc-N-(2,6-diethylacetanilide)-iminodiacetate in rats and dogs. Although all complexes studied exhibited high specificity for biliary excretion, they varied widely in disappearance rate from blood and in biliary excretion. Complexes with 8-hydroxyquinoline-7-carboxylic acid and hydralazine were relatively lipophilic and were eliminated more slowly than 131I-rose bengal; complexes of iminodiacetic derivatives of naphthalene, N-(2-acetylnaphthyl)iminodiacetic acid N-(2-naphthylmethyl)iminodiacetic acid were more polar and were eliminated much faster. Renal excretion of the complexes was 5.6% or less except for that of the latter compound (18%). Plasma binding ranged from 51 to 98%.