B-19036, a potential new hepatobiliary contrast agent for MR proton imaging

B-19036 is an octadentate chelate of the paramagnetic ion Gd3+ under investigation as a proton relaxation enhancer (PRE) in magnetic resonance (MR) proton imaging. Its relaxivity was determined at 0.5 T by pulse spectrometry in various biologic fluids and in liver tissue homogenate. The ligand selectivity versus gadolinium was assessed in comparison with that versus other ions of biologic interest. Acute toxicity was determined after intravenous (IV) and intracerebral administration to mice. Pharmacokinetic studies conducted in rats indicated that unlike Gd-DTPA, where excretion is exclusively renal, biliary route plays a significant role in the excretion of B-19036, suggesting its possible use for hepatobiliary imaging.