synthesis and biological testing of nonionic iodinated x-ray contrast media.

A series of nonionic x-ray contrast media containing novel linkages between the triiodobenzene and polyhydroxy moieties have been prepared and screened against established criteria. Of the coupler groups examined (amide including dipeptide, carbamate, ureido, and ester), amide showed the greatest overall utility in terms of safety, solubility, stability, and ease of synthesis. Acute toxicity, solubility and stability data are summarized for each series. In the CNS, certain compounds were well tolerated and some were devoid of any excitatory effects. Intrathecal tissue irritant effects were also unremarkable. Most agents exhibited relatively high osmolalities, raising questions as to the influence of this factor on the safety of myelographic agents. Intravascularly, nonionic media appear also to offer advantages over classical ionic media. However, nonionic media can exert positive inotropic effects and exhibit high viscosity at higher iodine concentrations. Nevertheless, overall results continue to demonstrate the radiographic potential of nonionic contrast media.