Technetium-99m labeled peptides for imaging inflammation

A reagent for preparing a technetium-99m (Tc-99m) radiolabeled peptide for imaging sites of inflammation within a mammalian body, comprising a specific binding peptide comprising platelet factor 4 or peptide fragments thereof wherein the peptide specifically binds to sites of inflammation, covalently linked to a Tc-99m binding moiety of formula selected from the group consisting of:

• Cp(aa)Cp I.
• wherein Cp is a protected cysteine and (aa) is an amino acid;
• A--CZ(B)--{C(R.sup.1 R.sup.2)}.sub.n --X II.
• wherein
• A is H, HOOC, H.sub.2 NOC, (peptide)-NHOC, (peptide)-OOC or R.sup.4 ;
• B is H, SH, --NHR.sup.3, --N(R.sup.3)-(peptide), or R.sup.4 ;
• X is H, SH, --NHR.sup.3, --N(R.sup.3)-(peptide) or R.sup.4 ;
• Z is H or R.sup.4 ;
• R.sup.1, R.sup.2, R.sup.3 and R.sup.4 are independently H or lower straight or branched chain or cyclic alkyl;
• n is 0, 1 or 2;
• and
• where B is --NHR.sup.3 or --N(R.sup.3)-(peptide), X is SH, and n is 1 or 2;
• where X is --NHR.sup.3 or --N(R.sup.3)-(peptide), B is SH, and n is 1 or 2;
• where B is H or R.sup.4, A is HOOC, H.sub.2 NOC, (peptide)-NHOC, (peptide)-OOC, X is SH, and n is 0 or 1;
• where A is H or R.sup.4, then where B is SH, X is --NHR.sup.3 or --N(R.sup.3)-(peptide) and where X is SH, B is --NHR.sup.3 or --N(R.sup.3)-(peptide);
• where X is H or R.sup.4, A is HOOC, H.sub.2 NOC, (peptide)-NHOC, (peptide)-OOC and B is SH;
• where Z is methyl, X is methyl, A is HOOC, H.sub.2 NOC, (peptide)-NHOC, (peptide)-OOC, B is SH and n is 0;
• where B is SH and X is SH, n is not 0;
• and wherein the thiol moiety is in the reduced form;
• and ##STR5## wherein X.dbd.H or a protecting group;
• (amino acid)=any amino acid;
• ##STR6## wherein each R.sup.5 is independently H, CH.sub.3 or C.sub.2 H.sub.5 ;
• each (pgp).sup.5 is independently a thiol protecting group or H;
• m, n and p are independently 2 or 3;
• A=linear or cyclic lower alkyl, aryl, heterocyclyl, combinations or substituted derivatives thereof;
• ##STR7## wherein each R.sup.5 is independently H, lower alkyl having 1 to 6 carbon atoms, phenyl, or phenyl substituted with lower alkyl or lower alkoxy;
• m, n and p are independently 1 or 2;
• A=linear or cyclic lower alkyl, aryl, heterocyclyl, combinations or substituted derivatives thereof;
• V=H or --CO-peptide;
• R.sup.6 =H or peptide;
• and wherein when V=H, R.sup.6 =peptide and when R.sup.6 =H, V=--CO-peptide;
• wherein the radiolabel-binding moiety forms a complex with a radioisotope and the complex is electrically neutral.