Gadolinium (III) complex equilibria: The implications for Gd(III) MRI contrast agents

✍ Scribed by Graham E. Jackson; Sinclair Wynchank; Marianne Woudenberg

• Publisher: John Wiley and Sons
• Year: 1990
• Tongue: English
• Weight: 561 KB
• Volume: 16
• Category: Article
• ISSN: 0740-3194
• DOI: 10.1002/mrm.1910160107

✦ Synopsis

Abstract

A computer model of blood plasma which has allowed the effect of Gd(III) contrast agents to be simulated has been developed. Initial binding of Gd(III) is to transferrin. At high concentration the metal ion binds to citrate and salicylate. At a concentrate of 10^−3^ M, GdCl~3~ is predicted to effect a redistribution of the in vivo Zn(II), Ca(II), and Fe(II) complexes present in blood plasma. There is little effect on the Cu(II) distribution. At a concentration below lo^−5^ M EDTA and DTPA have little effect on the free Gd(III) metal ion concentration. Above this concentration though, the metal ion is bound aimost exclusively to the EDTA or DTPA. An attempt is made to relate the toxicity of GdCl~3~, [Gd(EDTA)]^−^, and [Gd(DTPA)]^2−^ to the thermodynamic stability of these complexes. The effect of substitution kinetics is also discussed. © 1990 Academic Press, Inc.