Peptide-based compounds

1. A compound of general formula (I) having an affinity for the integrin receptors,

(I) wherein

G represents glycine, and

D represents aspartic acid, and

R 1 represents —(CH 2 ) n — or —(CH 2 ) n —C 6 H 4 — wherein

n represents a positive integer 1 to 3, and

X 1 represents a bond or 1 to 2 amino acid residues wherein each amino acid residue independently optionally can be derivatized with a carbohydrate, PEG-containing moiety or alkyl chain in order to modify the pharmacokinetics or blood clearance rates of said agents,

X 2 and X 4 represent independently an amino acid residue capable of forming a disulfide bond,

X 3 represents arginine, N-methylarginine or an arginine mimetic,

X 5 represents a hydrophobic amino acid and,

X 6 represents a thiol-containing amino acid residue, and X6 forms a thioether bridge linked to R1,

and k represents a positive integer 1 to 10, and

X 7 represents a linker (L) moiety comprising a PEG spacer, or

X 7 is absent and

X 8 represents a reporter (R) moiety, or is —NH 2 or is absent, and

pharmaceutical acceptable salts thereof.

2. A compound of claim 1 wherein R 1 represents —(CH 2 )—.

3. A compound of claim 1 wherein X 1 represents 1 or 2 amino-acid residues.

4. A compound of claim 1 wherein X 1 represents aspartic acid, tyrosine, tyrosine-aspartic acid, lysine, glutamic acid, acetyl-lysine, asparagine, serine, threonine or glutamine independently optionally can be derivatized with a carbohydrate, PEG-containing moiety or alkyl chain in order to modify the pharmacokinetics or blood clearance rates of said agents.

5. A compound of claim 1 wherein X 2 and X 4 independently represent a cysteine or homocysteine residue.

6. A compound of claim 1 wherein X 3 represents an arginine or a N-methylarginine residue.

7. A compound of claim 1 wherein X 5 represents a tyrosine, a phenylalanine, a 3-iodo-tyrosine or a naphthylalanine residue.

8. A compound of claim 7 wherein X 5 represents a phenylalanine or a 3-iodo-tyrosine residue.

9. A compound of claim 1 wherein X 6 represents a cysteine or a homocysteine residue.

10. A compound of claim 1 wherein the PEG spacer of X 7 is an O-bis-(aminoethyl)ethylene glycol unit.

11. A compound of claim 1 wherein X 7 is comprising a linker (L) moiety optionally comprising one or more ethylene glycol units.

12. A compound of claim 1 wherein k represents the positive integer 1 to 4.

13. A compound of claim 1 wherein k represents the positive integer 1.

14. A compound of claim 1 comprising any of the chelating agents

15. A compound of claim 1 wherein the chelating agent is capable of binding to a radionuclide.

16. A compound of claim 15 capable of binding to technetium, a radioisotope of iodine or Cu or a 18 F isotope.

17. A compound of claim 1 wherein any of the amino acid residues is independently a naturally occurring amino acid.

18. A compound of claim 17 wherein any of the amino acid residues is independently in the D or L conformation.

19. A compound of claim 1 or claim 14 defined by the following formulas: