Patent ID: 8268318

Claim:
A compound of the Formula (I) wherein: A is R 1 is a polyethylene glycol; L 1 and L′ 1 are each —NH(CH 2 ) 4 —, wherein —NH is connected to L 2 ; L 2 and L′ 2 are each —(CH 2 ) 2 —O—C(O)—, wherein —(CH 2 ) 2 is connected to R 1 ; Y 1 and Y′ 1 are independently O; R 2 , R′ 2 , R 3 , and R′ 3 are independently C 1-6 alkyl; R 4 and R′ 4 are independently biologically active moieties containing a hydroxyl moiety to form an ester; and (p) and (p′) are independently an integer from about 1 to about 3.