Patent ID: 7897647

Claim:
A compound comprising the formula: wherein: R 1 and R 2 are independently selected from the group consisting of polyethylene glycol, C 1-6 alkyls, aralkyls, and terminal branching groups; Y 1-3 are independently O, S or NR 11 ; L 1 and L 2 are independently selected bifunctional linkers; Z is selected from the group consisting of wherein L 3 is a bifunctional linker and Y 4 is O, S or NR 11 , hydrophobic moieties, bifunctional linking moieties and combinations thereof; R 3 -R 11 , R 24 and R 25 are independently selected from the group consisting of hydrogen, C 1-6 alkyls, C 3-19 branched alkyls, C 3-8 cycloalkyls, C 1-6 substituted alkyls, C 3-8 substituted cycloalkyls, aryls, substituted aryls, aralkyls, C 1-6 heteroalkyls, substituted C 1-6 heteroalkyls, C 1-6 alkoxy, phenoxy and C 1-6 heteroalkoxy; A is an organic compound containing an amine; a and c are each independently 0 or a positive integer; b, d and e are independently 0 or 1; and m, n, o, and p are independently selected positive integers, provided that at least one of R 1 and R 2 is a polyethylene glycol and the weight average molecular weight thereof is about 40,000 Da.