[Gd(DTPA-BDMA)] as a magnetic resonance contrast agent: Acute toxicity test and preliminary images

The new complex of Gd(III) with the 1,7-bis[(N-dimethyl(carbomoyl) methyl)-1,4,7-triazaheptane-1,4,7-triacetate [Gd(DTPA-BDMA)] is a non-ionic paramagnetic complex designed for use as an extracellular magnetic resonance imaging (MRI) contrast agent. The R1 relaxivity value of [Gd(DTPA-BDMA)] is 4.13 ± 0.2 mM^-1S^-1, which is similar to that of [Gd(DTPA)]^2- (4.08 mM^-1S^-1). The purpose of this study is to examine the acute toxicity and MRI characteristics of [Gd(DTPA-BDMA)]. Our results show that the lethal dose (LD₅₀) of the [Gd (DTPA-BDMA)] is 10.58 mmol/kg in ICR mice, which is higher than that of [Gd (DTPA)]^2-(6.40 mmol/kg). The MR images demonstrate that the enhancing effect and renal clearance of [Gd(DTPA-BDMA)] are similar to that of [Gd(DTPA)]^2- either in control group or CHA (Cheng hepatoma ascites) tumor model in Wistar rats (p>0.05). These findings indicate that [(DTPA-BDMA)] has similar characteristics of [Gd(DTPA)]^2- and has the potential of becoming a safe and reliable magnetopharmaceutical for the extracellular MRI contrast agent.