Biodistribution of Radiolabeled, Formulated Gadopentetate, Gadoteridol, Gadoterate, and Gadodiamide in Mice and Rats

Abstract

The molecular feature found to be most important in differentiating the four chelates evaluated is the presence or absence of a macrocyclic structure. The Gd chelates containing this structure, gadoteridol and gadoterate, have the lowest residual Gd at long residence times in both mice and rats. The order of residual whole body Gd at 14 days (lowest to highest) was: gadoteridol integral of gadoterate < or = gadopentetate << gadodiamide. The only excipient that affected the biodistribution was found in the gadodiamide formulation where the addition of 5% calcium (DTPA-BMA) reduced residual Gd to just less than 10 times greater than that found for the macrocyclic chelates with the lowest residual Gd, gadoteridol and gadoterate.