Patent ID: 7585837

Claim:
A compound of the formula: (X) n —Y wherein Y is a moiety of a drug bearing at least one functional group selected from free amino, carboxyl, phosphate, hydroxyl and/or mercapto, and X is a radical of the formula (i): wherein: R 1 is a radical containing a protein or a polymer carrier moiety wherein said polymer carrier has suitable functional groups and is selected from the group consisting of linear or branched polyethylene glycol (PEG) having a molecular weight in the range of 5000 to 80000 Da; copolymers of linear or branched PEG; poly(lactic acid) or copolymers thereof; polyesters having suitable functional groups based on polylactide (PLA), polyglycolide (PGA), polycaprolactone (PCL), or their copolymers; and polyamides based on polymethacrylamide or their copolymers; R 2 is selected from the group consisting of hydrogen, (C1-C8)alkyl, (C1-C8) alkoxy, (C1-C8)alkoxyalkyl, (C6-C10)aryl, (C1-C8)alkaryl, (C6-C10)ar(C1-C8)alkyl, halogen, nitro, —SO 3 H, —SO 2 NHR, amino, ammonium, carboxyl, PO 3 H 2 , and OPO 3 H 2 , and R is selected from the group consisting of hydrogen, (C1-C8)alkyl and (C6-C10)aryl; R 3 and R 4 , the same or different, are each selected from the group consisting of hydrogen, (C 1 -C 8 )alkyl and (C10-C10)aryl; A is a covalent bond when the radical is linked to a carboxyl, phosphate or mercapto group of the drug Y, or A is OCO when the radical is linked to an amino or hydroxyl group of the drug Y; n is an integer of at least one, or pharmaceutically acceptable salts thereof.