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Accueil > Publications > Recherche par années > Années 2000 > 2002

Nicolle, GM ; Toth, E ; Eisenwiener, KP ; Macke, HR ; Merbach, AE

From monomers to micelles : investigation of the parameters influencing proton relaxivity

Journal of Biological Inorganic Chemistry 7 (7-8) 757-769

par Administrateur - publié le

Abstract :

O-17 NMR and H-1 NMRD studies have been performed on a series of Gd(III) 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA) derivatives as potential liver-specific magnetic resonance imaging (MRI) contrast agents. They bear aliphatic side chains which make them capable of micellar self-organization. The compounds differ in the length (C10-C18) and in the chemical nature (alkyl or monoamide-alkyl) of their lipophilic chain. We have established a convenient method to determine the critical micellar concentration (cmc) of paramagnetic surfactants by H-1 relaxivity measurements. This technique can be easily used over a large temperature range ; thus, it can find wide application outside the field of MRI contrast agents. The knowledge of the cmc allowed us to determine the parameters governing the water proton relaxivity of the Gd(III) chelates in both nonaggregated and aggregated micellar forms. The relaxation data of the micellar complexes have been interpreted with the Lipari-Szabo approach.