Compositions and methods for assessing eye vasculature

1. A composition comprising a compound of structural Formula I

or a salt thereof; wherein

X 1 and X 2 are independently —CO(AA);

Y 1 and Y 2 are independently chosen from —OR 10 , —SR 11 , —NR 12 R 13 , —N(R 14 )COR 15 , —CONH(PS); —P(R 16 ) 2 , —P(OR 17 ) 2 and

each Z 1 is independently chosen from a bond, —CR 18 R 19 —, —O—, —NR 20 —, —NCOR 21 —, —S—, —SO—, and —SO 2 —;

each R 1 to R 21 are independently chosen from hydrogen, C 1 -C 10 alkyl, C 1 -C 10 alkyl substituted with hydroxyl and carboxylic acid, C 3 -C 6 polyhydroxylated alkyl, C 5 -C 10 aryl, C 5 -C 10 heteroaryl, C 3 -C 5 heterocycloalkyl, C 3 -C 5 heterocycloalkyl substituted with C(O), —(CH 2 ) a CO 2 H, —(CH 2 ) a CO 2 H substituted with C 5 -C 10 heteroaryl, —(CH 2 ) a CONR 30 R 31 , —(CH 2 ) a NHSO 3 − , —(CH 2 ) a NHSO 3 H, —(CH 2 ) a OH, —(CH 2 ) a OPO 3 = , —(CH 2 ) a OPO 3 H 2 , —(CH 2 ) a OPO 3 H − , —(CH 2 ) a OR 22 , —(CH 2 ) a OSO 3 − , —(CH 2 ) a OSO 3 H, —(CH 2 ) a PO 3 = , —(CH 2 ) a PO 3 H 2 , —(CH 2 ) a PO 3 H − , —(CH 2 ) a SO 3 − , —(CH 2 ) a SO 3 H, —(CH 2 ) d CO(CH 2 CH 2 O) c R 23 , (CHCO 2 H) a CO 2 H, —CH 2 (CHNH 2 ) a CH 2 NR 25 R 26 , —CH 2 (CHOH) a CO 2 H, —CH 2 (CHOH) a R 27 , —CH[(CH 2 ) b NH 2 ] a CH 2 OH, —CH[(CH 2 ) b NH 2 ] a CO 2 H, and —(CH 2 ) a NR 28 R 29 ;

each R 22 to R 31 are independently chosen from hydrogen, C 1 -C 10 alkyl, and C 1 -C 5 -dicarboxylic acid;

(AA) is a polypeptide chain comprising one or more natural or unnatural β-amino acids or γ-amino acids linked together by peptide bonds;

(PS) is a sulfated or non-sulfated polysaccharide chain comprising one or more monosaccharide units connected by glycosidic linkages; and

each ‘a’, ‘b’, and ‘d’ are independently chosen from 0 to 10, ‘c’ is chosen from 1 to100 and each of ‘m’ and ‘n’ independently is an integer from 1 to 3.

2. The composition of claim 1 , wherein Y 1 and Y 2 are each —NR 12 R 13 wherein one of R 12 and R 13 is hydrogen and the other of R 12 and R 13 is chosen from hydrogen and C 1 -C 10 alkyl.

3. The composition of claim 2 , wherein Y 1 and Y 2 are each —NR 12 R 13 wherein each of R 12 and R 13 is hydrogen.

4. The composition of claim 1 , wherein the compound of formula I is

(2R,2′R)-3,3′-(3,6-diaminopyrazine-2,5-dicarbonyl)bis(azanediyl))bis(2-(hydroxymethyl)propanoic acid.

5. The composition of claim 1 , wherein the composition is administered intravenously, intraperitoneally, subcutaneously or by infusion.

6. The composition of claim 5 , wherein the composition is administered intravenously.

7. The composition of claim 1 , wherein the compound fluoresces upon irradiation with non-ionizing radiation.

8. The composition of claim 7 , wherein the non-ionizing radiation has a wavelength of at least 350 nm.

9. The composition of claim 1 , wherein the compound of structural Formula I is hydrophilic or has rigid functionality.

10. The composition of claim 1 , wherein the compound of structural Formula I is at least partially renally excretable.

11. The composition of claim 1 , wherein the compound of structural Formula I is completely renally excretable.

12. The composition of claim 1 , wherein the composition further comprises a pharmaceutically acceptable carrier.