Contrast agent for NMR imaging comprising peptide structures

Abstract

The present invention relates to a contrast agent for NMR imaging constituted by a complex between a chelating agent and paramagnetic metal cations, wherein said complex corresponds to the formula I: ##STR1## or a physiologically acceptable salt of this complex, in which formula: n and n' are whole numbers from 1 to 4 R.sub.1 -R.sub.7 are selected from among H, a halogen, alkyl, alkoxy, aryl, alkenyl, and cycloalkyl groups; with the alkyl groups being optionally substituted by halogen, alkoxy, alkyl, nitrile, nitro or amino; >C(R.sub.6, R.sub.7) can in addition represent >C=O; the three substituents Y are identical or different and represent H or an ionic equivalent of a divalent or trivalent paramagnetic metal cation or of a physiologically acceptable cation derived from an inorganic or organic base, with the condition that at least two of the substituents Y represent ionic equivalents of paramagnetic metal cations.

Dependencies are inferred from the claim text.