Patent ID: 7157546

Claim:
A water-soluble polymer having the structure: wherein: POLY is a water-soluble polymer segment; X′ is a linker moiety; z′ is an integer from 3 to 12; R 1 , in each occurrence, is independently H or an organic radical selected from the group consisting of alkyl, substituted alkyl, alkenyl, substituted alkenyl, alkynyl, substituted alkynyl, aryl, and substituted aryl; R 2 , in each occurrence, is independently H or an organic radical selected from the group consisting of alkyl, substituted alkyl, alkenyl, substituted alkenyl, alkynyl, substituted alkynyl, aryl, and substituted aryl, and further wherein the following apply: when POLY is linear: (a) the total number of carbonyls present in said polymer is 0 or 2 or greater except when X′ comprises one or more contiguous (—CH 2 CH 2 O—) segments, (b) and further wherein X′ is oxygen or comprises at least one (—CH 2 CH 2 O—) segment, then at least one of R 1 or R 2 in at least one occurrence is an organic radical as defined above or said polymer is heterobifunctional, where POLY comprises a reactive group at one terminus that is not hydroxy, and when POLY is branched: (c) either (i) at least one of R 1 or R 2 in at least one occurrence is an organic radical as defined above or (ii) X′ includes —(CH 2 CH 2 O) b — where b is from 1 to about 20 in the instance where POLY comprises a lysine residue, (d) and further wherein said POLY has 2 polymer arms, then neither polymer arm comprises oxygen as the only heteroatom in the instance where POLY comprises “C—H” as a branch point.