Details

Autor(en) / Beteiligte

• Tircsó, Gyula
• Regueiro-Figueroa, Martín
• Nagy, Viktória
• Garda, Zoltán
• Garai, Tamás
• Kálmán, Ferenc Krisztián
• Esteban-Gómez, David
• Tóth, Éva
• Platas-Iglesias, Carlos

Titel

Approaching the Kinetic Inertness of Macrocyclic Gadolinium(III)-Based MRI Contrast Agents with Highly Rigid Open-Chain Derivatives

Ist Teil von

• Chemistry : a European journal, 2016-01, Vol.22 (3), p.896-901

Ort / Verlag

Germany: Blackwell Publishing Ltd

Erscheinungsjahr

2016

Quelle

Wiley-Blackwell Journals

Beschreibungen/Notizen

• A highly rigid open‐chain octadentate ligand (H4cddadpa) containing a diaminocylohexane unit to replace the ethylenediamine bridge of 6,6′‐[(ethane‐1,2 diylbis{(carboxymethyl)azanediyl})bis(methylene)]dipicolinic acid (H4octapa) was synthesized. This structural modification improves the thermodynamic stability of the Gd3+ complex slightly (log KGdL=20.68 vs. 20.23 for [Gd(octapa)]−) while other MRI‐relevant parameters remain unaffected (one coordinated water molecule; relaxivity r1=5.73 mm−1 s−1 at 20 MHz and 295 K). Kinetic inertness is improved by the rigidifying effect of the diaminocylohexane unit in the ligand skeleton (half‐life of dissociation for physiological conditions is 6 orders of magnitude higher for [Gd(cddadpa)]− (t1/2=1.49×105 h) than for [Gd(octapa)]−. The kinetic inertness of this novel chelate is superior by 2–3 orders of magnitude compared to non‐macrocyclic MRI contrast agents approved for clinical use. Open to imaging: The Gd3+ complex of a rigidified non‐macrocyclic octadentate ligand (cddadpa4−) shows favorable properties as a magnetic resonance imaging (MRI) contrast agent: high thermodynamic stability, relatively high relaxivity thanks to the presence of a coordinated water molecule, and a remarkable kinetic inertness comparable to those typically shown by complexes with macrocyclic ligands.