Abstract: Ligands for radiopharmaceutical use are capable of chelating radiometal species and of being bound to biological targeting molecules. The ligands have formula (a) and (b), where A, A'=--SZ or Y, B.dbd.O or S, Y.dbd. (c), Z.dbd.H or a thiol protecting group, m=2 or 3, n=2 or 3, q=0 or 1, R.dbd.H or unsubstituted or substituted hydrocarbon and pharmaceutically acceptable salts, provided that at least one CR.sub.2 group represents CO and forms, together with an adjacent N atom, a --CONR-- amide group.

Abstract: Novel metal chelating compounds, and radiometal, e.g., technetium-99m complexes thereof. The compounds can be used to radiolabel small biologically active species with minimal effect on their biodistribution and activity. The compounds have formula (a) or (b): ##STR1## where Z is (CR.sub.2).sub.n or (CR).sub.n, n is 2 or 3, X is a ligand comprising S, N or O, each R is H or C1-C20 substituted or unsubstituted hydrocarbon group, provided that 1-3 CR.sub.2 groups represent a CO (amide) moiety, and provided that 1-3 R may each comprise a targeting group and/or a protein reactive functionality.

Abstract: Ligands for radiopharmaceutical use are capable of chelating radiometal species and of being bound to biological targeting molecules. The ligands have the formula (a) and (b), where A, A'=--SZ or Y, B=O or S, Y=(c), Z=H or a thiol protecting group, m=2 or 3, n=2 or 3, q=0 or 1, R=H or unsubstituted or substituted hydrocarbon and pharmaceutically acceptable salts, provided that at least one CR.sub.2 group represents CO and forms, together with an adjacent N atom; a --CONR-- amide group.

Abstract: A conjugate comprises a linear or cyclic synthetic peptide of 3-50 amino acids linked via one of its carboxyl groups and optionally via a linking group, to a polydentate metal chelating group, with the result that endo- or exo-peptidase metabolism of the peptide is substantially inhibited, with the provisos that: a) the peptide chain contains a biological targeting sequence which is biologically active; b) when the spacer is absent the metal chelating group does not comprise solely peptide moieties; c) the metal chelating group does not contain thiol donors. A complex of the conjugate with a metal atom chelated by the metal chelating group is useful in medicine.

Abstract: Novel selenium derivatives of steroids have the formula I, ##STR1## where X is hydrogen or acyl, Y is hydrocarbon and n is 0 or 1, preferably 0. Such compounds, labelled with selenium-75 are of use for investigating body function, particularly for imaging the adrenal glands, and are claimed superior for the purpose to the 6.beta.- and 19- iodine derivatives of cholesterol.

Abstract: Novel selenium-75 derivatives of cholesterol have the formula ##STR1## (I) where X is hydrogen or acyl, Y is alkyl and n is 0 or 1. They are useful for visualizing the adrenal glands of mammals.

Abstract: Novel dimeric and monomeric selenium-75 derivatives of steroids are made by reacting a keto steroid with selenium-75 dioxide or selenious acid-Se75. The resulting diselenide dimers can be converted into monomeric compounds by the use of a cleaving reagent followed by an alkylating agent. The compounds are useful in saturation analyses such as radioimmunoassays.