Ligandin binding phthalein complexone complex of technetium for hepatic function studies

In our pursuit for liver functional diagnosis, development of bifunctional radiopharmaceutical containing iminodiacetic acid (IDA), as the technetium chelating site along with phthalein or fluorescein structure, the skeleton of BSP and Rose Bengal, long used for the assessment of liver function is considered. Among the various PC, PPC, TPC and calcein IDA derivatives commercially available, 99mTc-PC (PC: 3,3'-bis(N, N-dicarboxymethylaminomethyl)o-cresolphthalein) showed the highest hepatobiliary excretion. The functionality of the various technetium labeled phthalein and fluorescein IDA derivatives was evaluated by competitive BSP binding studies and by comparative binding with the hepatocyte specific protein, ligandin.