Patent ID: 8309680

Claim:
A polymeric reagent having a structure of the following formula: Z—[(X 1 ) a -POLY 1 -(X 2 ) b -L 1 -(X 3 ) c ] m —(X 4 ) d —POLY 2 -Z Formula (Ia), wherein: each POLY 1 and POLY 2 , which may be the same or different, is a water-soluble and non-peptidic polymer; each X 1 , X 2 , X 3 , and X 4 , which may be the same or different, is a spacer moiety; each L 1 is a disulfide linkage; each Z, which may be the same or different, is a capping group or a functional group, and may optionally include a spacer moiety, with the proviso that at least one Z is a functional group; each a, b, c, and d, which may be the same or different, is either zero or one; m is an integer in the range of 1-10 and represents the number of polymer segments, POLY 1 , covalently attached in series; wherein the polymeric reagent is not in the form of a hydrogel.