Patent ID: 8530444

Claim:
A compound represented by the structure set forth in Formula (II) in which R 3 is selected from hydrogen, C 1 , C 2 , C 3 , C 4 , C 5 , C 6 , C 7 or C 8 linear or branched alkyl; L is selected from C 1 , C 2 , C 3 , C 4 , C 5 , C 6 , C 7 or C 8 linear, branched or cyclic alkyl, C 1 , C 2 , C 3 , C 4 , C 5 , C 6 , C 7 or C 8 linear, branched or aryl, or a combination thereof; U is selected from —(CO)O—; —O(CO)—NH—; or —(CO)—NH—; D is a drug; and pharmaceutically acceptable salts, and metal chelates of the compound.