Comparison in rabbits of chole-scintigraphic properties of several 99mTc-IDA derivatives

Pathways and kinetics of excretion were compared to four 99mTc-IDA derivatives in healthy rabbits of both sexes. Assessment of differences between the compounds was based upon: plasma clearance, characteristics of time-activity curves measured scintigraphically over the liver (time of the peak Tmax; time for decline of activity to half the peak value-T50%), and hepatocytic mean transit time (MTT) as derived after deconvolution of the hepatic time-activity curve. Hepatocyte transit time was short and similar to 99mTc-complexes of Mebrofenin, 2,4-diethyl IDA (HEPIDA) and 3-iodo-2,6-diethylphenylcarbamoylmethyliminodiacetic acid (JODIDA); it was evidently longer for 99mTc-p-butyl-IDA (BIDA). 99mTc-HEPIDA displayed significant urinary elimination; the remaining three compounds were excreted practically completely via the biliary route. It is concluded that optimal parameters were displayed by 99mTc-Mebrofenin and 99mTc-JODIDA.