Patent ID: 6150432
Filing Date: 2000-11-21
Classification: A61L,C08L,Y10S

Abstract:
A method of improving the biocompatibility of a polymer, comprising the steps of: (1) providing a polymer having desirable mechanical and/or physical properties in solution or dispersion in a liquid vehicle to provide a liquid polymer composition;(2) dispersing or dissolving into the liquid polymer composition a zwitterionic polymer bearing zwitterionic pendant groups to produce a liquid blended composition;wherein the zwitterionic polymer is formed from a radical polymerisable monomer including zwitterionic monomer of formula (I)Y--B--X (I)wherein B is a straight or branched alkylene, an oxaalkylene or an oligo-oxaalkylene chain optionally containing one or more fluorine atoms up to and including perfluorinated chains, or, if X contains a carbon-carbon chain between B and the zwitterionic moiety or if Y contains a terminal carbon bonded to B, a valence bond;X is a zwitterionic group,Y is an ethylenically unsaturated polymerisable group selected from ##STR22## wherein: R is hydrogen or a C.sub.1 -C.sub.4 alkyl group;A is --O-- or --NR'-- where R.sup.1 is hydrogen or a C.sub.1 -C.sub.4 alkyl group or R.sup.1 is --B--X where B and X are as defined above; andK is selected from the group consisting of:--(CH.sub.2).sub.p OC(O)--,--(CH.sub.2).sub.p C(O)--,--(CH.sub.2).sub.p OC(O)O--,--O(CH.sub.2).sub.p NR.sup.2 --,--(CH.sub.2).sub.p NR.sup.2 C(O)--,--(CH.sub.2).sub.p C(O)NR.sup.2 --,--(CH.sub.2)NR.sup.2 C(O)O--,--(CH.sub.2).sub.p OC(O)NR.sup.2 --,--(CH.sub.2).sub.p NR.sup.2 C(O)NR.sup.2 -- (in which the R.sup.2 groups are the same or different), --(CH.sub.2).sub.p O--, --(CH.sub.2).sub.p SO.sub.3 --, and optionally in combination with B, a valence bond, and p is from 1 to 12 and R.sup.2 is hydrogen or a C.sub.1 -C.sub.4 alkl group;provided that the cationic moiety of the zwitterionic group is located at a distant end of the pendant X group from the B group; and(3) optionally in addition dispersing or dissolving into the liquid polymer composition or into the liquid blended composition at least one additive selected from the group consisting of plasticisers, fillers, colourants, UV absorbers, antioxidants and preservatives, said additives being biocompatible and(4) removing the liquid vehicle from the liquid blended composition of step (2) or step (3) to provide a solid blend.