Synthesis and Physicochemical Characterization of New C-Functionalized Derivatives of the Gadolinium(III) Complex with 3,6,10-Tris(carboxymethyl)-3,6,10-triazadodecanedioic Acid (H5ttda) Exhibiting Fast Water Exchange – Potential Paramagnetic Reporters for Molecular Imaging
✍ Scribed by Sophie Laurent; Luce Vander Elst; Antoine Vroman; Robert N. Muller
- Publisher
- John Wiley and Sons
- Year
- 2007
- Tongue
- German
- Weight
- 162 KB
- Volume
- 90
- Category
- Article
- ISSN
- 0018-019X
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✦ Synopsis
To confirm the observation that [Gd(ttda)] derivatives have a significantly shorter residence time t M of the coordinated H 2 O molecule than [Gd(dtpa)], four new C-functionalized [Gd(ttda)] complexes, [Gd(4-Me-ttda)] (1), [Gd(4-Ph-ttda)] (2), [Gd(9-Me-ttda)] (3), and [Gd(9-Ph-ttda)] (4), were prepared and characterized (H 5 ttda ¼ 3,6,10-tris(carboxymethyl)-3,6,10-triazadodecanedioic acid; H 5 dtpa ¼ 3,6,9-tris(carboxymethyl)-3,6,9-triazaundecanedioic acid). The temperature dependence of the proton relaxivity for these complexes at 0.47 T and of the 17 O transverse relaxation rate of H 2 17 O at 7.05 T confirm that the proton relaxivity is not limited by the H 2 O-exchange rate. The residence time of the H 2 O molecules in the first coordination sphere of the gadolinium complexes at 310 K, as calculated from 17 O-NMR data, is 13, 43, 2.9, and 56 ns for 1, 2, 3, and 4, respectively. At 310 K, the longitudinal relaxivity of 2 is higher than for the parent compound [Gd(ttda)] and the other complexes of the series. The stability of the new compounds was studied by transmetallation with Zn 2þ ions. All the new complexes are more stable than the parent compound [Gd(ttda)].