Synthesis,Characterization, and Biodistribution of a Dinuclear Gadolinium Complex with Improved Properties as a Blood Pool MRI Agent |
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Authors: | Francesca La Cava Dr. Alberto Fringuello Mingo Luigi Miragoli Prof. Enzo Terreno Enrico Cappelletti Dr. Luciano Lattuada Dr. Luisa Poggi Dr. Sonia Colombo Serra |
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Affiliation: | 1. Center of Excellence for Preclinical Imaging (CEIP), Department of Molecular Biotechnologies and Health Sciences, University of Torino, Colleretto Giacosa (TO), Italy;2. Bracco Research Centre, Bracco Imaging SpA, Colleretto Giacosa (TO), Italy |
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Abstract: | A dinuclear gadolinium(III) chelate containing two moieties of diethylenetriaminepentaacetic acid (DTPA), covalently conjugated to an analogue of deoxycholic acid, was synthesized and thoroughly characterized. A full relaxometric analysis was carried out, consisting of 1) the acquisition of nuclear magnetic resonance dispersion (NMRD) profiles in various media; 2) the study of binding affinity to serum albumin; 3) the measurement of 17O transverse relaxation rate versus temperature, and 4) a transmetallation assay. In vivo biodistribution MRI studies at 1 T and blood pharmacokinetics assays were carried out in comparison with Gd‐DTPA (Magnevist) and gadocoletic acid trisodium salt (B22956/1), two well‐known Gd complexes that share the same chelating cage and the same deoxycholic acid residue of the Gd complex investigated herein ((GdDTPA)2‐Chol). High affinity for plasma protein and, in particular, the availability of more than one binding site, allows the complex to reach a fairly high relaxivity value in plasma (~20 mm ?1 s?1, 20 MHz, 310 K) as well as to show unexpectedly enhanced properties of blood pooling, with an elimination half‐life in rats approximately seven times longer than that of B22956/1. |
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Keywords: | blood pool dinuclear gadolinium GBCAs magnetic resonance imaging |
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