Abstract: Copolymers of zwitterionic monomer, especially 2-methacryloyloxyethyl-2?-trimethylammoniumethyl phosphate inner salt, and hydrophobic comonomer, especially dodecylmethacrylate, are made in a monomer starved polymerization process in which solutions of monomers are fed to the reaction vessel in which initiator is present over an extended period. The copolymers have improved compositional uniformity and provide better coatings on a range of substrates. The novel copolymers can be distinguished from prior art batch type bulk solution polymerization polymers of the same monomer composition by solubility characteristics especially in alcohol/water mixtures. Particularly preferred coating compositions comprise an alcohol:water mixture containing around 20 to 40% by volume alcohol.

Abstract: Anion exchange material surfaces are provided with zwitterionic and cationic groups, preferably by coating with a polymer formed from monomers including a zwitterionic monomer, a cationic monomer and, optionally, a termonomer providing stable binding at the substrate surface. The ion exchange materials may be used to scavenge heparin from blood by an ion exchange separation process. The zwitterionic group reduces the rate of fouling by biological materials such as proteins.

Abstract: A polymer is formed from monomers including a zwitterionic monomer, a cationic monomer and a hydrophobic termonomer. The polymer may be cross-linkable. The polymer may be coated onto a surface from a liquid coating composition followed by contacting the coated surface with heparin. The double coated substrates have improved heparin activity over extended periods as compared to heparinised surfaces which are commercially available. Other anionically charged mucopolysaccharides may be used. The polymers may also scavenge heparin from treated blood to avoid use of potentially toxic heparin inhibitors. Preferably the terpolymer is formed from 2-methacryloyloxyethyl-2-(trimethylamonium)phosphate inner salt, choline methacrylate and n-dodecyl methacrylate.

Abstract: The present invention relates to materials which comprise a surface having pendant groups of formula (I), in which the groups --B-- are the same or different, preferably the same, and each is --CH.sub.2 -- or --C(.dbd.O)--, preferably --CH.sub.2 --, R.sup.1 is hydrogen alkyl of 1 to 12, preferably 1 to 4 carbon atoms, or a group capable of bonding to, or bonded to, a ligand or R.sup.1 is a polymerisable, preferably ethylenically unsaturated, group and Z is a zwitterionic group. Usually both groups B are the same and are joined to identical groups so that the compound of formula (I) is achiral. New compounds are achiral glyceryl phosphatidyl choline analogues. Surfaces having the groups (I) at their surface have improved biocompatibility, and show reduced fibrinogen absorption, reduced platelet activation, reduced microorganism adhesion and are useful in the production of implants or prostheses, for extra-corporeal circuitry for body fluids, for treating membranes of various type, for contact lenses.

Abstract: The present invention provides materials which comprise a surface having pendant zwitterionic groups Z comprising, as anion, a phosphate, sulphonate, carboxylate or phosphate-ester group or a phosphate ester group in which one or more of the ester oxygen atoms is replaced by --S--, --NH-- or by a valence bond and, as cation, an ammonium, phosphonium or sulphonium moiety, provided that where the anion is a phosphate-ester group or derivative thereof or sulphonate and the cation is a trialkyl quaternary ammonium group (the alkyl groups each containing from 1 to 4 carbon atoms) and the group linking the anion and cation moieties is an alkylene group, the alkylene group, contains at least 5, preferably at least 6, and more preferably at least 7, carbon atoms. The materials have improved biocompatibility for instance as evidenced by reduced protein deposition and reduced platelet activation.