摘要:
Metal complexes of new ligands of the formula ##STR1## are useful as agents for medical imaging, particularly MRI, for in vitro or in vivo diagnostic or as radiopharmaceuticals. In these compounds, X--R.sup.1 --Y is a coordinating group able to form a highly stable complex with metal ions. Suitable units are for example derivatives of ortho-phenanthroline or of an hydroxamic acid. R.sup.2 and R.sup.3 are reactive functions such as amines or carboxylic groups. R.sup.4 and R.sup.5 are ligands, for instance diethylenetriaminepentaacetic acid 1,4,7,10-tetraacetic acid (DTPA), 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA) or 1,4,8,11-tetraazacyclotetradecane-N, N', N", N'"-tetraacetic acid (TETA), of a different type than the X--R.sup.1 --Y units and able to strongly encapsulate metal ions with which the X--R.sup.1 --Y moieties form less stable chelates. Stable high molecular weight multimetallic entities are spontaneously formed by these ligands that spontaneously associate around metal ions through the X--R.sup.1 --Y units. Higher relaxivities thus are achieved. Mixed-complexes containing two different radionuclides are also obtained thus allowing imaging and therapy with one single chelate.