title: Novel gadolinium(III) polyaminocarboxylate macrocyclic complexes as potential magnetic resonance imaging contrast agents.
abstract: Two novel Gd(III) complexes with functionalised polyaminocarboxylate macrocycles, 1,4,7-tris(carboxymethyl)-9,24-dioxo-14,19-dioxa-1,4,7,10,23- pentaazacyclododecane (L(1)) and 1,4,7-tris(carboxymethyl)-9,25-dioxo-14,17,20-trioxa-1,4,7,10,23- pentaazacyclotridecane (L(2)), were prepared in good yield. Their potential use as magnetic resonance imaging (MRI) contrast agents (CAs) was evaluated by investigating their relaxation behaviour as a function of pH, temperature and magnetic field strength. The 1/T(1) proton relaxivities at 20 MHz and 25 degrees C of GdL(1) (5.87 mM(-1) s(-1)) and GdL(2) (6.14 mM(-1) s(-1)) were found to be significantly higher than the clinically used Gd 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (Gd(DOTA)(-)) and Gd diethylenetriaminepentaethanoic acid (Gd(DTPA)(2-)). The complexes possess one water molecule in the inner coordination sphere whose mean residence lifetime was estimated to be 1.1 and 1.5 micros at 25 degrees C by variable temperature (VT) (17)O NMR spectroscopy.
authors.affiliation: Department of Chemistry and Open Laboratory of Chemical Biology of the Institute of Molecular Technology for Drug Discovery and Synthesis, The University of Hong Kong, Pokfulam Road, Hong Kong, PR China.
authors.forename: Kannie Wai-Yan
authors.initials: KW
authors.lastname: Chan
authors.forename: Serena
authors.initials: S
authors.lastname: Barra
authors.forename: Mauro
authors.initials: M
authors.lastname: Botta
authors.forename: Wing-Tak
authors.initials: WT
authors.lastname: Wong
mesh_terms: D003287:Contrast Media / Q000737:chemistry*; D005682:Gadolinium; D019786:Gadolinium DTPA; D006571:Heterocyclic Compounds; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008279:Magnetic Resonance Imaging / Q000379:methods; D009682:Magnetic Resonance Spectroscopy; D009942:Organometallic Compounds / Q000737:chemistry*; D013696:Temperature
chemical_list: D003287:Contrast Media; D006571:Heterocyclic Compounds; D009942:Organometallic Compounds; C050823:gadolinium 1,4,7,10-tetraazacyclododecane-N,N',N'',N'''-tetraacetate; D005682:Gadolinium; D019786:Gadolinium DTPA