Fibrosis specific multimeric peptidomimetic radiotracers

1. A method of making a contrast agent, said method comprising:

(a) providing an organic chelating ligand, wherein said organic chelating ligand selected from the group consisting of:

wherein

R is t-butyl ester, ester or hydrogen; and

R 1 is

(b) reacting said organic chelating ligand with a linking moiety, wherein said linking moiety having a primary amine and a carboxylic moiety at opposing ends;

(c) deprotecting one or more carboxylic acid ester of said organic chelating ligand to yield one or more carboxylic acid functionality;

(d) chelating a metal ion to result in a metal chelate, wherein said linking moiety on said metal chelate having said carboxylic moiety;

(e) providing a multivalent scaffold, wherein said multivalent scaffold is selected from the group consisting of:

wherein

R 2 is Boc, Fmoc, Ac, Cbz, Bz or Bn;

L 1 and L 2 are linkers; and

R 1 is

(f) conjugating said multivalent scaffold with a targeting ligand to yield one or more targeting ligand conjugated multivalent scaffold;

(g) deprotecting an amino protecting group on said one or more targeting ligand conjugated multivalent scaffold to obtain an amine containing targeting ligand conjugated multivalent scaffold; and

(h) reacting said amine containing targeting ligand conjugated multivalent scaffold with said carboxylic moiety of said metal chelate under a condition capable of forming an amide bond to results in said contrast agent.

2. The method of claim 1 , wherein said linkers L 1 and L 2 are selected from the group consisting of alkane, amino acid, —NHCO(CH 2 ) 5 —, polyethylene glycol and polypropylene glycol.

3. The method of claim 1 , wherein said contrast agent is in a form of pharmaceutically acceptable salts, hydrates and solvates.

4. The method of claim 1 , wherein said targeting ligand is

wherein L 3 is independently selected from the group consisting of alkane, amino acid, polyethylene glycol and polypropylene glycol.

5. The method of claim 1 , wherein said metal ion is selected from the group consisting of Cu, Tc Mn, Re, In, Tb, Tm, Tl, Sm, Lu, Ga, Yb, Y, Gd, Eu, and a lanthanide.

6. The method of claim 5 , wherein Cu, Fe, Mn, Tm, Yb, Y, Gd, Eu, or a lanthanide is chelated for magnetic resonance imaging.

7. The method of claim 5 , wherein Cu, Tc, Re, In, Tb, Tm, Tl, Sm, Lu, Ga, or Y is chelated for nuclear imaging.

8. A method of making a contrast agent, said method comprising:

(a) providing an organic chelating ligand, wherein said organic chelating ligand selected from the group consisting of

wherein

R is t-butyl ester, ester or hydrogen; and

R 1 is

(b) reacting said organic chelating ligand with a linking moiety to yield a terminal carboxylic moiety on said organic chelating ligand, wherein said linking moiety having a primary amine and a carboxylic moiety at opposing ends;

(c) providing a multivalent scaffold, wherein said multivalent scaffold is selected from the group consisting of

wherein

R 2 is Boc, Fmoc, Ac, Cbz, Bz or Bn;

L 1 and L 2 are linkers; and

R 1 is

(d) conjugating said multivalent scaffold with a targeting ligand to yield one or more targeting ligand conjugated multivalent scaffold;

(e) deprotecting an amino protecting group on said one or more targeting ligand conjugated multivalent scaffold to obtain an amine containing targeting ligand conjugated multivalent scaffold;

(f) reacting said amine containing targeting ligand conjugated multivalent scaffold with said terminal carboxylic moiety on said organic chelating ligand under a condition capable of forming an amide bond to results in an organic chelating ligand containing targeting ligand conjugated multivalent scaffold;

(g) deprotecting one or more carboxylic acid ester of said organic chelating ligand containing targeting ligand conjugated multivalent scaffold to yield one or more carboxylic acid functionality; and

(h) chelating a metal ion to said one or more carboxylic acid functionality on said organic chelating ligand containing targeting ligand conjugated multivalent scaffold to results in said contrast agent.

9. The method of claim 8 , wherein said linkers L 1 and L 2 are selected from the group consisting of alkane, amino acid, —NHCO(CH 2 ) 5 —, polyethylene glycol and polypropylene glycol.

10. The method of claim 8 , wherein said contrast agent is in a form of pharmaceutically acceptable salts, hydrates and solvates.

11. The method of claim 8 , wherein said targeting ligand is

wherein L 3 is independently selected from the group consisting of alkane, amino acid, polyethylene glycol and polypropylene glycol.

12. The method of claim 8 , wherein said metal ion is selected from the group consisting of Cu, Tc, Fe, Mn, Re, In, Tb, Tm, Tl, Sm, Lu, Ga, Yb, Y, Gd, Eu, and a lanthanide.

13. The method of claim 12 , wherein Cu, Fe, Mn, Tm, Yb, Y, Gd, Eu, or a lanthanide is chelated for magnetic resonance imaging.

14. The method of claim 12 , wherein Cu, Tc, Re, In, Tb, Tm, Tl, Sm, Lu, Ga, or Y is chelated for nuclear imaging.