TC-99M-DIETHYL MONOIODO-IDA - A RADIOPHARMACEUTICAL FOR HEPATOBILIARYSCINTIGRAPHY

Tc-99m-3-iodo-2,6-diethyl phenyl carbamoyl methyl iminodiacetic acid ( Tc-99m-diethyl monoiodo-IDA) was prepared and evaluated for hepatobili ary scintigraphy. The pharmaceutical had less plasma protein binding c apacity and greater lipophilicity as compared to those of DISIDA, mebr ofenin and iodofenin. High hepatobiliary specificity, medium transit t ime and high gall bladder to liver ratio of the agent were perceptible from organ distribution data in mice. Blood T(max) and clearance T1/2 of the radiopharmaceutical were observed at 2 and 4.8 min respectivel y. Data on renal excretion, hepatic uptake (T1/2, 2 min; T(max), 5 min ) and release (T1/2, 9.2 min) suggest the suitability of this agent fo r hepatobiliary imaging. The above contention is further supported by comparing its hepatic kinetics with those of iodofenin and mebrofenin in rabbits. Serial imaging of hepatobiliary system in rabbits at vario us time intervals is in confirmation with the kinetic data.