Preparation and in vitro evaluation of a novel amphiphilic GdPCTA-[12] derivative;: a micellar MRI contrast agent

A novel amphiphilic GdPCTA-[12] derivative has been prepared. The complex formed micelles in aqueous solution with a relatively low CMC, 0.15 mM (25 degreesC). The concentration dependent T-1-relaxivity (r(1)) of the system has been described. The maximum T-1-relaxivity, 29.2 s(-1) mM(-1) (20 MHz, 25 degreesC), was higher than for previously described micellar MRI contrast agents. This high T-1-relaxivity is a consequence of the favourable water residence time (tau(m)) and the fact that the complex is heptadentate allowing two water molecules to coordinate to the gadolinium ion (q = 2).