Polychelants as contrast enhancing agents

Abstract

The present invention provides a polychelant compound of formula (VII), (wherein each X which may be the same or different is NZ, O or S, at least two Xs being NZ; B is (CR.sup.1 Y) or --N(CR.sup.1.sub.2 Y)--; each Z is a group R.sup.1 or a group CR.sup.1.sub.2 Y, at least one Z being a group CR.sup.1.sub.2 Y; each Y is a group CO.sub.2 H, PO.sub.3 H, SO.sub.3 H, CONR.sup.1.sub.2, CON(OR.sup.1)R.sup.1, CNS or CONR.sup.1 NR.sup.1.sub.2 ; m is 0 or 1 or 2; each n is 2 or 3; q is 0 or 1 when B is (CR.sup.1 Y) and 2 when B is N(CR.sup.1.sub.2 Y); p is an integer having a value of at least 2; each R.sup.1 which may be the same or different is a hydrogen atom or an alkyl, aryl or aralkyl group optionally substituted by one or more hydroxy or alkoxy groups, or two R.sup.1 groups on ring atoms or in Z groups together represent a linker group L; each L which may be the same or different represents a bond or an organic linker group having a molecular weight of less than 1000 and salts and chelates thereof. These compounds, especially the diand trichelates with paramagnetic or heavy metal ions are especially useful as diagnostic imaging contrast agents.

Dependencies are inferred from the claim text.