Patent ID: 7781551

Claim:
A biocompatible polymer of the chemical formula: in which, R 1 and R 2 are independently a hydrogen or methyl; R 3 is a zwitterion group having the formula: in which A 5 is selected from the group consisting of —O—, —S— and —NH—; R 16 is selected from the group consisting of alkanediyl, —C(O)alkylene- and —C(O)NHalkylene-; the R 3 17 groups are independently selected from the group consisting of hydrogen, 1 to 4 carbon atoms or, taken together with the nitrogen to which they are bonded , a heterocyclic ring of 5 to 7 atoms; R 5 is an ethyl or methyl; n is in an range from about 0.01 to about 0.75; and m is in a range from about 0.25 to about 0.99.