Patent Description:
In recent years, antimicrobial materials have been widely used as a coating for various surfaces, especially those used in medical applications. These coatings reduce the likelihood of complications based on infection. Anti-fouling materials have also been used to coat these surfaces and reduce the likelihood of device related complications.

<CIT> discloses biocompatible polymers comprising phospholipid moieties and at least one non-fouling moiety.

<CIT> discloses biologically active polymeric compositions which comprise at least one pharmacologic material other than heparin chemically bonded to a polymer backbone such that the pharmacologic material retains its biological properties.

<CIT> discloses polymeric materials incorporating an infection resistant biguanide compound pendant to the polymer chain, being chemically bound thereto through some but not all of the amine nitrogen atoms of the infection resistant biguanide compound.

<CIT> discloses biocompatible compositions that comprise a hydrophobic polymer backbone and a pendant hydrophilic spacer group bonded to said backbone, optionally linked to a bioactive agent.

<NPL>, discloses heparin-coupled poly(poly(ethylene glycol) monomethacrylate)-Si hybrids, prepared via surface-initiated atom transfer radical polymerization of a poly(ethylene glycol)monomethacrylate macromonomer on a hydrogen-terminated Si surface.

Polymeric materials are described herein that can be coated onto various articles and can give enhanced antimicrobial properties and reduced platelet adhesion. These polymeric materials can be used to make or coat a range of medical devices. Embodiments of the present invention include anti-microbial polymers and anti-thrombogenic polymers as defined in the claims.

Polymers described herein have been found to have surprisingly superior antimicrobial activity over polymers currently in use, especially with regard to against gram negative bacteria (e.g. Pseudomonas aeruginosa).

It may be observed that a non-thrombogenic component generally has the property not to enhance protein/platelet binding or activate platelets - that is to say, it may be seen as a passive phenomenon to prevent clot formation; whereas an antithrombogenic component may be seen as an active phenomenon, one where (for example) heparin and other polysaccharides, including glycosaminoglycans, play a specific role in preventing clot formation.

More specifically, the invention provides compounds, polymeric coatings, medical devices, and methods for making a polymer, both as set out in the appended claims, and in other aspects as further described in this specification.

The compounds of the invention may further comprise a lubricant group and/or an anti-fouling group covalently bound to the polymer. Lubricant groups and anti-fouling or non-fouling groups are groups which have lubricant or anti-fouling or non-fouling effects respectively in the environment in which the invention is at a relevant time deployed. Thus a lubricant group includes a group or moiety that reduces the coefficient of friction of a compound or coating of the invention, in a relevant environment, when compared with a corresponding compound or coating without such group or moiety. In a corresponding manner, anti-fouling or non-fouling groups mitigate or prevent the laying down and adhesion of biological and/or chemical entities on to a surface. The invention also extends to polymeric coatings comprising the compounds of the invention. Such a polymeric coating may comprise a compound of the invention blended with a lubricant and/or an anti-fouling or non-fouling compound.

In preferred embodiments of the invention, the polymeric coating may include a lubricant that comprises an N-vinyl pyrrolidone group and/or a glycerol methacrylate group. In further preferred embodiments, the polymeric coating may include an anti-fouling compound that comprises one or more of methacryloyloxyethyl phosphorylcholine, <NUM>-((<NUM>-(methacryloyloxy)ethyl)dimethylammonio)ethyl <NUM>-methoxyethyl phosphate, <NUM>-((<NUM>-(methacryloyloxy)ethyl)dimethylammonio)propyl <NUM>-methoxyethyl phosphate, or a combination thereof.

The invention extends to medical devices in which such compounds or coatings are exploited, and specifically to medical devices having a coating according to the invention. Such medical devices can include, but are not limited to, an artificial blood vessel, a cardiac stent, a venous stent, an arterial stent, a kidney stent, a ureter stent, a valve, a cardiac valve leaflet, a shunt, a cardiac device, a pacemaker, a transcutaneous catheter, a dialysis port, or a port for chemotherapy. The compounds and coating will typically be applied to surfaces of the devices that are to be exposed, in use, to biological environments, such as fluids, tissues and the like.

The invention further extends to a method for making a polymer according to the claims.

The term "agent" as used in the claims and description herein, in the expressions "antithrombogenic agent", "antimicrobial agent" "therapeutic agent", "lubricant agent", "anti-fouling functional agent" and the like, extends not only to compounds as such, including but not limited to monomers and polymers, but also to correspondingly active parts of compounds, such as radicals and groups, having the relevant property.

Polymers are molecules built up by the repetition of smaller units that are sometimes called monomers. Polymers are typically made by special chemical schemes that make the monomers chemically react with each other to form molecular chains that can range in length from short to very long molecules. Polymers can be assembled into larger materials; for example, many polymers may be linked together to form a hydrogel. The polymers may be crosslinked or may be free of crosslinks. Crosslinks are covalent bonds that link one polymer chain to another.

The antithrombogenic and antimicrobial groups may be pendant groups, which are independently chosen and attached to the polymer backbone. The various pendant groups will be independently attached to the polymer backbone so that the polymer will comprise the polymer backbone and a plurality of the pendant groups. Further, other pendant groups may be attached to the polymer, or the polymer may be free of pendant groups besides the antithrombogenic and/or antimicrobial groups. Polymer compositions generally have a distribution of molecular weights that can generally be characterized by an average property. The polymer, or the polymer backbone, may range in weight from, for instance, a minimum of <NUM> Daltons, or a minimum of <NUM>,<NUM> Daltons, up to a maximum of, for instance, <NUM>,<NUM>,<NUM> Daltons or <NUM>,<NUM>,<NUM> Daltons. Thus exemplary molecular weight ranges for the polymer, or for the polymer backbone, of <NUM> to <NUM>,<NUM>,<NUM> Daltons, or of <NUM>,<NUM> to <NUM>,<NUM>,<NUM> Daltons, are possible. Highly crosslinked polymer may not be readily characterized by a molecular weight, but the polymer can then be characterized by the polymer chain within the polymer and a degree of crosslinking. The amount of the antithrombogenic or antimicrobial group, which may be a pendant group, may be freely varied, for instance from about <NUM>% to about <NUM>% w/w of the total compound that includes the pendant group. In further embodiments the concentration (that is to say, the weight proportion) of the antithrombogenic pendant group to the total weight of the polymer may be at least <NUM>%, or at least <NUM>%, and may be not more than <NUM>%, or not more than <NUM>%. Thus the concentration ranges for the antithrombogenic group include, for example, about <NUM>% to about <NUM>%, or from about <NUM>% to about <NUM>%. In further embodiments the concentration (weight proportion) of the antimicrobial pendant group to the total weight of the polymer may be at least <NUM>%, or at least <NUM>%, and may be not more than <NUM>%, <NUM>%, or <NUM>%. Thus the concentration ranges for the antimicrobial group include, for example, about <NUM>% to about <NUM>%, or from about <NUM>% to about <NUM>% or <NUM>%. A person of ordinary skill in the art will recognize that additional ranges are contemplated and are within the present disclosure. Artisans will immediately appreciate that all values and ranges within the expressly stated limits are contemplated. To achieve these ranges, for instance, the monomer compound may be polymerized from a concentrated state, or mixed with various other monomers for polymerization. Or a polymer may be selected to serve as the polymer backbone and lightly or heavily decorated with antithrombogenic/antimicrobial pendant groups, as well as other pendant groups.

<FIG> shows a series of three light microscopy photographs (photomicrographs) each made at a magnification of x400 of the platelet adhesion of an uncoated polyurethane (<FIG>), a polyurethane coated with a polymer of <NUM>% PHMB-polymer (where PHMB denotes polyhexamethylene biguanide) and <NUM>% heparin polymer (<FIG>), and a polyurethane coated with a polymer of <NUM>% PHMB-polymer and <NUM>% heparin polymer (<FIG>), after exposure to 1x10<NUM> platelets/ µl platelet rich plasma (PRP). It is apparent that the combination coatings each reduce the platelet adhesion.

<FIG> is a graph showing biofilm-mediated turbidity for haemodialysis catheters coated with either antimicrobial or combination polymers (antimicrobial + heparin) and challenged with Pseudomonas aeruginosa. Specifically, <FIG> shows the turbidity of solutions associated with substrates coated with combination polymers (combinational polymer <NUM>, designated A, and combinational polymer <NUM>, designated B), antimicrobial polymers (designated C), and uncoated (D).

The substrate is treated with a bacterial source, given a proper amount of time for the bacteria to adhere to the surface, and then rinsed. The treated substrate is then placed in solution and the bacteria are allowed to proliferate. After a set period of time, the optical density (OD) of the solution is measured. Higher OD indicates that there are more bacteria present in the solution and therefore there were more bacteria present on the substrate. It can be seen in <FIG> that combination polymers provide significant improvements in antimicrobial proprieties with regard to P. aeriginosa over both uncoated substrates and substrates coated with an antimicrobial-only polymer.

<FIG> is a series of three light microscopy photographs (photomicrographs x400) of the platelet adhesion of an uncoated polyurethane (<FIG>), a polyurethane coated with the combination polymer <NUM> (<FIG>) and a polyurethane coated with the combination polymer <NUM> (<FIG>) as tested in <FIG> after exposure to 1x10<NUM> platelets/ µl PRP. The combination coatings are seen to reduce the platelet adhesion.

Example <NUM> describes the synthesis of an antithrombogenic monomer. Generally a monomer (e.g. poly(ethylene glycol) methacrylate) comprising a polymerizable group (e.g. methacrylate) with an attachment group (e.g. poly(ethylene glycol)) is activated and then mixed with the desired antithrombogenic group, typically in an active form, such as a salt. The monomer is then purified. A process similar to the one in Example <NUM> is used to create the antimicrobial monomer in Examples <NUM>-<NUM>, <NUM>, and <NUM>.

Example <NUM> describes the process for complexing the antithrombogenic monomer if necessary to protect the functional group or make it easier to dissolve the monomer. The monomer/polymer can be decomplexed as described in Example <NUM>.

Example <NUM> describes the process for synthesizing an antimicrobial polymer. In general the antimicrobial monomer is mixed with one or more co-monomers, degassed, and heated to the reaction temperature. The polymerization initiator is then added. The reaction is allowed to progress to a desired viscosity and then is quenched. The resulting polymer is then purified. A similar process to the one in Example <NUM> is used to create antimicrobial polymers in Example <NUM>.

Example <NUM> describes the process for synthesizing an antithrombogenic polymer. In general the antithrombogenic monomer is mixed with one or more co-monomers, degassed, and heated to the reaction temperature. The polymerization initiator is then added. The reaction is allowed to progress to a desired viscosity and then is quenched. The resulting polymer is then purified. A similar process to the one in Example <NUM> is used to create antithrombogenic polymers in Examples <NUM>-<NUM>.

Examples <NUM>-<NUM> describe possible process for coating a substrate with a polymeric coating using heat curing, UV curing, and dip coating.

Example <NUM> describes the method for testing the antimicrobial proprieties of coated substrates. Generally, test pieces are exposed to a particular medium (to enable protein adhesion etc.) such as plasma, blood or urine etc. for a predetermined time point, pieces are then washed then put into the test protocol. The test protocol effectively incubated the device with live microorganisms, washed the device to removed "solution present bacteria", allowed the active component sufficient time to "kill", then transferred to growth media where viable microorganisms on the device will proliferate into daughter cells in solution hence increasing turbidity of growth media which can then be measured by optical density.

Example <NUM> describes the method for testing the platelet adhesion of a substrate. Generally, test pieces may (or may not be) exposed to a particular medium (to enable protein adhesion etc.) such as plasma, blood or urine etc. for a predetermined time point, pieces are then washed then put into the test protocol. The test protocol consists of exposing the treated pieces to plasma containing a certain concentration of platelets and allowed to sit overnight.

Example <NUM> describes the method for testing heparin activity.

Example <NUM> describes the general procedure for testing the activity of various coatings against Pseudomonas aeruginosa. The method is similar to the one described with regard to <FIG>. <FIG> (Biofilm-mediated turbidity for haemodialysis catheters coated with either Antimicrobial or combination polymers (antimicrobial + heparin) and challenged with Pseudomonas aeruginosa) shows the results from Example <NUM>, and it is clear from this graph that combination coatings show surprisingly superior antimicrobial activity relative to both the uncoated catheter and the antimicrobial polymer against Pseudomonas aeruginosa.

Examples <NUM>-<NUM> are conducted in a similar manner to Example <NUM>. <FIG> (Biofilm-mediated turbidity for haemodialysis catheters coated with either antimicrobial or combination polymers (antimicrobial + heparin) and challenged with Enterococcus faecalis) shows the results from Example <NUM>, and it is clear from this graph that combination coatings show superior antimicrobial activity relative to the uncoated catheter against Enterococcus faecalis. <FIG> (Turbidity for haemodialysis catheters coated with either antimicrobial or combination polymers (antimicrobial + heparin) and challenged with Escherichia coli following overnight plasma incubation) shows the results from Example <NUM>, and it is clear from this graph that combination coatings with a high heparin content show surprisingly superior antimicrobial activity relative to both the uncoated catheter and the antimicrobial polymer against Escherichia coli. <FIG> (Turbidity for haemodialysis catheters coated with either Antimicrobial or combination polymers (antimicrobial + heparin) and challenged with Staphylococcus aureus following overnight plasma incubation) shows the results from Example <NUM>, and it is clear from this graph that combination coatings with a high heparin content show surprisingly superior antimicrobial activity relative to both the uncoated catheter and the antimicrobial polymer against Staphylococcus aureus. <FIG> (Activity of Blended Polymer and Antimicrobial Polymer (on polyurethane haemodialysis catheters) against Staphylococcus aureus post plasma incubation) shows the results from Example <NUM>, and it is clear from this graph that combination coatings show superior antimicrobial activity relative to the uncoated catheter against Staphylococcus aureus. <FIG> shows the results from Example <NUM>, and it is clear from this graph that combination coatings show superior antimicrobial activity relative to the uncoated catheter against Pseudomonas aeruginosa.

Example <NUM> tests the platelet adhesion as described above, for surfaces coated with antimicrobial, combination (antimicrobial + heparin) or blended (antimicrobial + heparin) polymers. The results are shown in <FIG>.

Example <NUM> describes the heparin activity overtime for a combination polymer. The results (Surface heparin activity (by IIa) for Combination Polymer (High Heparin) Coated PUR strips over a <NUM> week serial incubation in PBS) are shown in <FIG>.

Examples <NUM>-<NUM>, <NUM>, and <NUM> describe the process for polymerizing an antimicrobial monomer. In general the antimicrobial monomer is mixed with one or more co-monomers, degassed, and heated to the reaction temperature. The polymerization initiator is then added. The reaction is allowed to progress to a desired level of viscosity and then is quenched. The resulting polymer is then purified.

Antimicrobial functional groups are capable of killing, preventing the proliferation of, or inhibiting, or at least substantially slowing the growth of susceptible classes of microorganisms. Microorganisms include but are not necessarily limited to bacteria, viruses, fungi, yeasts, algae, and other life forms. Antimicrobial functional groups include guanide groups, biguanide groups, and quaternary amines.

Guanide groups have a portion of the compound with the general formula:
<CHM>
In accordance with the invention, R<NUM>, R<NUM>, R<NUM>, and R<NUM> are independently chosen from a group consisting of hydrogen, substituted or unsubtituted alkyl chains, substituted or unsubstituted cycloalkyls, substituted or unsubstituted aryls, substituted or unsubstituted alkoxys, amidines, and amines.

Biguanide groups are a subgroup of guanide and have a portion of the compound with the general formula:
<CHM>
In accordance with the invention, R<NUM>, R<NUM>, R<NUM>, and R<NUM> are independently chosen from a group consisting of hydrogen, substituted or unsubstituted alkyl chains, substituted or unsubstituted cycloalkyls, substituted or unsubstituted aryls, substituted or unsubstituted alkoxys, amidines, and amines. Preferred R<NUM>, R<NUM>, R<NUM>, and R<NUM> combinations include those set out for guanides above.

Suitable antimicrobial groups with biguanide and/or guanide groups include poly(guanides), poly(biguanides), poly(hexamethylene biguanide), chlorhexidine and their derivatives. Derivatives of the antimicrobial functional groups are also suitable for use as an antimicrobial functional group. Derivatives are compounds that can be derived from the parent compound by some chemical or physical process. Generally, they are similar in structure to the parent compound and possess similar characteristics. In some embodiments, the antimicrobial functional group may be a derivative of a groups containing a guanidine or biguanide group, for example poly(hexamethylene biguanide). Suitable derivatives of guanides, biguanides, and poly(hexamethylene bigaunide), notably guanide derivatives, polyaminopropyl biguanide derivatives, polyhexamethylene guanidine, and polyhexamethylene guanidine derivatives, and vinvylic and methacrylic derivatives of the foregoing antimicrobial groups, include those disclosed, for example, in <CIT>, <CIT>, <CIT>, <CIT>, <CIT>, <CIT>, , <CIT>, <CIT>, <CIT>, and <CIT>.

Quaternary amine groups are cationic compounds comprising a group of the general formula:
<CHM>.

In accordance with the invention, R<NUM>, R<NUM>, R<NUM>, R<NUM> are independently selected from the group consisting of heteroatoms, substituted or unsubstituted alkyl chains, substituted or unsubstituted cycloalkyls, substituted or unsubstituted aryls, substituted or unsubstituted alkoxys, amidines, and amines. Suitable quaternary amine groups occur in organosilicon quaternary ammonium compounds and <NUM>-(trimethoxysilyl) propyldidecylmethyl ammonium salts. Others include benzalkonium chloride, benzethonium chloride, methylbenzethonium chloride, cetalkonium chloride, cetylpyridinium chloride, cetrimonium, cetrimide, dofanium chloride, tetraethylammonium bromide, didecyldimethylammonium chloride and domiphen bromide. Further suitable antimicrobial quaternary amine groups are disclosed in <CIT>, <CIT>, <CIT>; <CIT>; <CIT>; <CIT>; <CIT>; <CIT>; <CIT>; <CIT>; <CIT>; <CIT>; <CIT>; <CIT>; <CIT>; and <CIT>.

Antithrombogenic functional groups reduce the amount of thrombus formation in the body, generally following the introduction of a foreign object. Polysaccharides are polymers made from combinations of sugar monomer. Some polysaccharides have antithrombogenic properties including glycosaminoglycans, heparin, and their derivatives. Suitable antithrombogenic functional groups include heparin and heparin derivatives, glycosaminoglycans, warfarin, hirudin, hyaluronic acid, dermatan sulfate, polysaccharides, mucopolysaccharides, chondroitin sulfate, keratan sulfate, monomers having sulphate groups, sulphonate groups, sulphamate groups, polyoxyalkylene ether groups; zwitterionic groups, <NUM>-sulphoethyl methacrylate, <NUM>-sulphoethyl acrylate, <NUM>-sulphopropyl methacrylate, <NUM>-sulphopropyl ethoxy methacrylate, <NUM>-sulphopropyl acrylate, <NUM>-sulphatobutyl methacrylate, <NUM>-sulphatobutyl acrylate, allyl sulphate, methyl allyl sulphate, <NUM>-buten-<NUM>-sulphate, <NUM>-methyl-<NUM>-buten-<NUM>-sulphate, <NUM>-methyl-<NUM>-buten-<NUM>-sulphate, <NUM>-sulphatoethyl methacrylamide, <NUM>-sulphatoethyl acrylamide, <NUM>-sulphatopropyl methacrylamide, <NUM>-sulphatopropyl acrylamide, <NUM>-sulphatobutyl methacrylamide, <NUM>-sulphatobutyl acrylamide, sulphato polyoxyalkylene methacrylate, sulphato polyoxyalkylene acrylate, <NUM>-sulphamatoethyl methacrylate, <NUM>-sulphamatoethyl acrylate, <NUM>-sulphamatopropyl methacrylate, <NUM>-sulphamatopropyl acrylate, <NUM>-sulphamatobutyl methacrylate, <NUM>-sulphamatobutyl acrylate, allyl sulphamate, methyl allyl sulphamate, <NUM>-sulphamatoethyl methacrylamide, <NUM>-sulphamatoethyl acrylamide, <NUM>-sulphamatopropyl methacrylamide, <NUM>-sulphamatopropylacrylamide, <NUM>-sulphamatobutyl ethacrylamide, <NUM>-sulphamatobutyl acrylamide, sulphamato polyoxyalkylene methacrylate, and sulphamato polyoxyalkylene acrylate. As can be seen from the foregoing named examples, the suitable monomers having sulphate, sulphonate and sulphamate groups, etc., can include polymerisable groups having carbon-carbon double bonds, especially acrylic and methacrylic groups. Further suitable antithrombogenic compounds and functional groups can be found in <CIT> and <CIT>. Heparin groups are polysaccharides having a portion of the compound with the general formula:
<CHM>.

Derivatives of the antithrombogenic functional groups are also suitable for use as an antithrombogenic functional group. Derivatives are compounds that can be derived from the parent compound by some chemical or physical process. Generally, they are similar in structure to the parent compound and possess similar characteristics. In some embodiments, the antithrombogenic functional group may be a heparin derivative. Heparin derivatives, for example, include benzalkonium heparin, heparin sulfate, heparan sulfate, heparin ammonium, heparin benzyl ester, heparin calcium, heparin lithium, heparin sodium heparin salt, low and high molecular weight heparin, sulfated heparin, aminated heparin, heparin methacrylate, heparin quaternary ammonium salt complex methacrylate, heparin methacrylate salt, and heparin polyethylene glycol methacrylate.

A polymerizable group is a functional group that can be reacted to form a polymer. Polymerizable groups can be polymerizable by free-radical polymerization, addition polymerization, or condensation polymerization. Various monomers that contain polymerizable groups are disclosed in <CIT>, <CIT>, <CIT>, <CIT>, <CIT>, <CIT><CIT><CIT><CIT><CIT><CIT><CIT><CIT><CIT><CIT><CIT><CIT><CIT><CIT><CIT><CIT><CIT><CIT><CIT><CIT><CIT><CIT>; <CIT>, and <CIT>. Further suitable polymerizable groups include poly(ethylene) oxide, polyethylene glycol, polyvinyl pyrrolidinone, polyacrylate, polymethylacrylate, polyalkylene oxide, methacrylic acid or other vinylic monomers, an acyl chloride, for example methacryloyl chloride, an isocyanate, or <NUM>-isocyanatoethyl methacrylate an electrophilic poly(ethylene glycol) methacrylate (PEGMA). If PEGMA is used, PEGMA is made electrophilic by reacting it with epichlorohydrin first to attach an epoxide group onto PEGMA. The epoxide can then react with the amine on a functional group. The expoxide can also be reacted with other functional groups, such as -OH, -COOH etc. Also, PEGMA can be reacted with carbonyldiimidazole to give a reactive group that can further react with -NH, -OH, -COOH.

Free radical polymerization is, in general, accomplished with a vinylic or allylic group, including acrylates and methacrylates. A monomer may be polymerized by itself or with co-monomers that also undergo free radical polymerization. Examples of co-monomers include one or more of: acrylates, methacrylates, <NUM>-hydroxyethyl methacrylate, hydroxypropyl methacrylate, n-butyl methacrylate, tert-butyl methacrylate, n-hexyl methacrylate, <NUM>-methoxyethyl methacrylate, poly(hexanide) methacrylate, poly(hexanide) polyethylene oxide methacrylate, or alkyl derivatized poly(hexanide) methacrylate, heparin derivatized polyethylene oxide macromer, vinyl sulfonic acid monomer, monomers comprising poly(ethylene glycol), N-vinyl pyrrolidone monomers, <NUM>-benzoylphenyl methacrylate allyl methyl carbonate, allyl alcohol, allyl isocyanate, methacryloyloxyethyl phosphorylcholine.

In some embodiments of the invention, the antimicrobial and/or the antithrombogenic groups are covalently bound to their respective polymerizable groups through an attachment group. These attachment groups are generally a part of the backbone precursor and contain a reactive group that reacts with the desired amines or hydroxides to form the monomers, e.g. monomers containing vinylic or allylic groups, for example polyhexamethylene biguanide methacrylate. A variety of chemical options exist for making the linkage. For instance, the attachment group may be a substituted or unsubstituted hydrocarbon chain ranging from <NUM> to <NUM> carbons, a substituted or unsubstituted alkyl, a substituted or unsubstituted aryl, a substituted or unsubstituted cycloalkyl, a substituted or unsubstituted cycloalkenyl, a substituted or unsubstituted heterocycle, a substituted or unsubstituted alkenyl, a functional chain comprising an ester, a functional chain comprising an amide, a functional chain comprising a urea, a functional chain comprising a carbonate, a functional chain comprising a carbamate, a functional chain comprising a poly(ethylene oxide), and a functional chain comprising a poly(propylene) oxide polymer. The term substituted or unsubstituted is used to describe chemical functional group that may be itself substituted with one or more additional substitute groups. These additional substitute groups can include hetero atoms such as O, N, or S. However the number, substitution position and type of bonded substituent are not specifically limited unless specifically stated. Further suitable attachment groups include groups such as hydroxyl, carboxyl, anhydride, isocyanate, allyl, vinyl, acrylate, methacrylate, epoxide, sulfonic, or sulfate groups. Linkage to the polymer may be by covalent bonding (including grafting) or by ionic bonding. Chemical binding to a secondary amine nitrogen atom by means of isocyanate results in a substituted urea linkage, or by means of isothiocyanate results in a substituted thiourea linkage, or by means of expoxide results in a beta-hydroxyltertiary amine, or by means of acid chloride results in a N,N-disubstituted amide, or by means of acid anhydride results in a N,N-disubstituted amide, or by means of aldehyde or ketone results in N,N-disubstituted hemiaminals or aminals depending on the aldehyde or ketone, or by means of unsaturated bonds results in a tertiary amine linkage.

A polymer is a molecule composed of repeated subunits. The subunits are commonly referred as a monomeric unit or a mer. The term monomer is typically used to refer to a chemical subunit that is reactable to make a polymer. Polymers of only a few monomeric units are sometimes referred to as oligomers. The term polymer includes the meanings of homopolymer, copolymer, terpolymer, block copolymer, random copolymer, and oligomer. A polymer may include a block. A series of identical monomeric units joined together forms a block. A polymer may have no blocks, or a plurality of blocks. A copolymer is a polymer having at least two different monomeric units. Some copolymers have blocks, while others have random structures, and some copolymers have both blocks and regions of random copolymer bonding. Copolymers may be made from reactive monomers, oligomers, polymers, or other copolymers.

Free radical polymerization techniques are powerful tools for making polymers. In this technique, monomers in a solution are activated to form free radicals. A monomer with a free radical reacts with another monomer, forming a covalent bond, and that other monomer is activated to form a free radical. The resultant chain reaction is used to form polymers. There are other ways to form polymers, as well as techniques to include polymers or oligomers in the process of making a new polymer. These are well known to artisans and there are many such processes in common use. A process for making a copolymer is to join two other polymers together (precursor polymers, or precursors, in this context), typically by using functional groups on the two precursors that can react with each other to form a covalent bond. One of each of the two precursor polymers might be joined end to end to make a copolymer, or the precursors might be reacted to make polymers that have many of the precursors joined together. Two or more polymer precursors can be used. The processes detailed herein for making polymers can also be used to make copolymers. Moreover, polymers as described herein can have additional chemical groups, e.g., polymers, in their backbone. In polymer science, the backbone chain or main chain of a polymer is the series of covalently bonded atoms that together create the continuous chain of the molecule.

Accordingly, embodiments of the invention include polymers as defined in the claims.

The polymer may be crosslinked or may be free of crosslinks. Crosslinks are covalent bonds that link one polymer chain to another. Embodiments include polymers (a term including copolymers) that are crosslinked with a polyfunctional crosslinker. A polyfunctional crosslinker, as that term is used herein, is a molecule that comprises a two or more reactive groups that will form a covalent bond with the polymer. Some embodiments include polyfunctional crosslinkers having between <NUM> and <NUM> reactive groups; artisans will immediately appreciate that all ranges and values between the explicitly stated ranges are contemplated, for instance, lower limits of <NUM> or <NUM>, or upper limits of <NUM> or <NUM>, so suitable ranges may be between <NUM> and about <NUM> or from <NUM> to about <NUM>. Examples include vinyls, epoxides, aldehydes, imines, isocyanates, benzophenones, aziridines, maleimides, diimides, carbodiimides, and succinimides. Further suitable crosslinkers include vinyl sulfonic acid, glycidyl methacrylate and other epoxide functional groups, alcohol methacrylate (HEMA) and <NUM>-benzoylphenyl methacrylate These functional groups may be provided on a polymer that comprises an antimicrobial or antithrombogenic group or on separate polyfunctional crosslinker molecules. For instance, the reactive groups may be placed on a backbone of polyethylene glycol, polyvinyl pyrrolidinone, polyacrylate, polymethylacrylate, or polyalkylene oxide. The crosslinker may be added to a solution of the polymer, or otherwise contacted with the polymer. Crosslinking will take place upon mixing or may be activated when desired, depending upon the particular chemistry involved. The polyfunctional crosslinker may be part of a melt or solution comprising the polymer, or added before, or after, such a polymer is contacted with a surface.

The invention may be performed, and embodiments may be made, by the following process. In general, a backbone monomer that comprises the desired attachment group is reacted with the desired amine position on the antimicrobial precursor. The resulting product is a polymerizable group connected to an antimicrobial agent by an attachment group, forming an antimicrobial monomer. Similarly, a backbone monomer that comprises the desired attachment group is reacted with the desired amine or hydroxide position on the antithrombogenic precursor. The resulting product is a polymerizable group connected to an antithrombogenic agent by an attachment group, forming an antithrombogenic monomer.

In some embodiments polymerization occurs through a free radical process. In general the antithrombogenic monomer or the antimicrobial monomer is mixed with one or more co-monomers, degassed, and heated to the reaction temperature. The reaction temperature may be above about <NUM>, or from about <NUM> to about <NUM>, or from about <NUM>° to about <NUM>. The polymerization initiator (for example potassium persulfate) is then added followed by the missing antithrombogenic monomer or antimicrobial monomer. The reaction is allowed to progress for a determined amount of time and then is quenched. The reaction may be allowed to progress for at least <NUM> minutes, for about <NUM> minutes to about <NUM> minutes, for about <NUM> minutes to about <NUM> minutes, for no more than about <NUM> minutes, or for no more than about <NUM> minutes. The resulting polymer is then purified. A person of ordinary skill in the art will recognize that additional ranges are contemplated and are within the present disclosure. All values and ranges within the expressly stated limits are contemplated.

In further embodiments the antimicrobial and antithrombogenic monomers may be polymerized separately. In general the antimicrobial monomer is mixed with one or more co-monomers, degassed, and heated to the reaction temperature. The polymerization initiator is then added. The reaction is allowed to progress to a desired viscosity and then is quenched. The resulting polymer is then purified. The antithrombogenic monomer is mixed with one or more co-monomers, degassed, and heated to the reaction temperature. The reaction temperature may be above about <NUM>, from about <NUM> to about <NUM>, or from about <NUM>° to about <NUM>. The polymerization initiator (for example potassium persulfate) is then added. The reaction is allowed to progress to a desired viscosity and then is quenched. The resulting polymer is then purified. The two polymers are then blended together in a desired ratio. A person of ordinary skill in the art will recognize that additional ranges are contemplated and are within the present disclosure. All values and ranges within the expressly stated limits are contemplated.

In some embodiments the antimicrobial precursor is a compound comprising a biguanide group with the desired amine position being a part of the biguanide group. In such embodiments the antimicrobial precursor may be a hydrochloride salt comprising a biguanide group. The salt may first be neutralized with a strong base. The biguanide group is then reacted with a backbone monomer that comprises the desired attachment group, as shown in Reaction Scheme <NUM> below. In further embodiments the antimicrobial precursor is a compound comprising a biguanide group with the desired amine position being a primary amine, cyanoamine, or cyanoguanidine group that is not part of the biguanide group. In such embodiments the antimicrobial precursor may be a hydrochloride salt comprising a biguanide group. The precursor is reacted with a backbone monomer that comprises the desired attachment group without first neutralizing the salt, as shown in Reaction Scheme <NUM> below.

In some embodiments the antithrombogenic precursor is a compound comprising a heparin group, with the heparin group comprising a hydroxide or a primary amine. In such embodiments the antithrombogenic precursor is reacted with an activated backbone monomer that comprises the desired attachment group, as shown in Reaction Scheme <NUM>. The heparin group may by complexed with benzalkonium prior to the reactions. If the heparin group is complexed it may be decomplexed prior to use as a coating. The backbone monomer may be activated by reacting with an amide, as shown in Reaction Scheme <NUM>. <CHM>
<CHM>
<CHM>.

A coating is a substance that provides complete or partial coverage of an item. A coating may be a single layer or may be more than one layer with each layer comprising the same compound or different compounds. In some embodiments, the coating will have only one layer with the antimicrobial/antithrombogenic polymer or polymer blend along with any other desired compounds. The layer may consist essentially of the antimicrobial/antithrombogenic polymer or polymer blend. In further embodiments the coating will have multiple layers with at least one layer consisting essentially of the antimicrobial/antithrombogenic polymer or polymer blend. When a layer consists essentially of the polymer or polymer blend, the polymer or polymer blend is at least about <NUM>% of the layer by weight. In some embodiments the polymer or polymer blend may be at least about <NUM>%, <NUM>%, or <NUM>% of the layer by weight. Additional ranges are contemplated and are within the present disclosure. All values and ranges within the expressly stated limits are contemplated.

In some embodiments, it may be desirable to polymerize the polymer compounds described herein with the material of the medical device directly. In other embodiments, the copolymers can be dissolved in solution to be coated onto medical devices using any suitable solution coating method, including dip-coating, spray coating (ultrasonic, electrostatic, thermal), dip-coating with UV cure, or dip-coated and cross-linked with a polyfunctional crosslinker (e.g. polyaziridines, polyisocyanates).

Suitable medical apparatus for coating include medical devices such as contact lenses, catheters for vascular access (both arterial and venous), abdominal cavity tubing, drainage bags and connectors of various kinds, catheters, blood bags, dialysis or other membranes, surgical gloves, surgical instruments, vascular grafts, stents, contact lenses and intra-ocular lenses, contact lens cases, bottles, diagnostic apparatus, oxygenators, heart valves and pumps, artificial blood vessels, cardiac stents, venous stents, arterial stents, kidney stents, ureter stents, cardiac valve leaflets, shunts, cardiac devices including pacemakers, transcutaneous catheters, dialysis ports, or ports for chemotherapy.

In some embodiments the polymers may comprise additional pendant groups or co-monomers and/or may be blended with other polymers or compounds to give the coatings additional beneficial properties. These additional compounds and pendant groups include lubricants, hydrophilic compounds and pendant groups, non-fouling compounds, therapeutic agents, and crosslinkers.

Examples of co-monomers can be found in <CIT> Monomers for mixing with the polysaccharide macromers can include, but are not limited to, monomers with hydroxyl groups (e.g., hydroxyethyl methacrylate), monomers with glycerol groups (e.g., glycerol monomethacrylate, glycerol dimethacrylate, glycerol trimethacrylate), monomers with polyoxyalkylene ether groups (e.g., polyethylene glycol methacrylate, polypropylene glycol methacrylate), monomers with vinyl groups (e.g., N-vinyl pyrrolidone), monomers with zwitterionic groups (e.g., <NUM>-methacryloyloxyethyl-<NUM>-(trimethyl ammonium)phosphate, monomers with silicone groups (e.g., methacryloxypropyl tris(trismethyl-siloxy)silane and other silicone methacrylate or acrylates), monomers having sulphate groups (e.g., vinyl sulphonic acid), monomers having sulphonate groups (e.g., ammoniun sulphatoethyl methacrylate), heparin monomer as cited in the patent <CIT> and <CIT>,.

Lubricants as a class are, in general, groups or moieties that reduce the coefficient of friction. Useful lubricants include N-vinyl pyrrolidone, glycerol, glycerol methacrylate, glycols, polyethylene glycol methacrylate, phosphoryl choline and derivatives thereof. Examples of suitable lubricants can be found in <CIT> One suitable lubricant disclosed therein is a biocompatible, lubricious, hydrophilic material comprising a terpolymer of <NUM> to <NUM> mole percent of a polymerizable monomer (<NUM>) having a polyethylene oxide unit with an average degree of polymerization from <NUM> to <NUM> and a polymerizable carbon-carbon double bond, <NUM> to <NUM> mole percent of a polymerizable monomer (<NUM>) having a polyethylene oxide unit with an average degree of polymerization from <NUM> to <NUM> and polymerizable carbon-carbon double bond, and <NUM> to <NUM> mole percent of an alkyl methacrylate (<NUM>):.

[CH<NUM>-C(R)-CO-[-O-CH<NUM>-CH<NUM>-]n1-O-R] CH<NUM>-C(R)-CO-(-O-CH<NUM>-CH<NUM>-)n1-O-R<NUM>     (<NUM>).

where m is from <NUM> to <NUM>. Monomers (<NUM>) and (<NUM>) are hydroxy or, preferably, methoxy polyethyleneglycol acrylates or, preferably, methacrylates, and provide the hydrophilic moieties in the terpolymer. Monomer (<NUM>), ranging from butyl to octadecyl methacrylate, provides the hydrophobic moieties. The preferred molar proportions of (<NUM>), (<NUM>) and (<NUM>) are about <NUM>% each of (<NUM>) and (<NUM>) and <NUM>% of (<NUM>). In weight terms, proportions of <NUM> to <NUM>% of (<NUM>), <NUM> to <NUM>% of (<NUM>) and <NUM> to <NUM>% of (<NUM>) are generally appropriate. It is preferred that monomer (<NUM>) has polyethylene oxide units with a degree of polymerization n1 from <NUM> to <NUM>, more especially a degree of polymerization n1 from <NUM> to <NUM>. It is preferred that monomer (<NUM>) has polyethylene oxide units with a degree of polymerization n2 from <NUM> to <NUM>, more especially a degree of polymerization n2 from <NUM> to <NUM>. It is preferred that monomer (<NUM>) is n-butyl methacrylate. Further suitable lubricants include N-vinylpyrrolidone.

Hydrophilic groups are well known in the art, and the term is well understood. Suitable hydrophilic groups include N-vinyl pyrrolidone, glycerol, glycerol methacrylate, glycols, polyethylene glycol methacrylate, phosphoryl choline and derivatives thereof. Examples of suitable hydrophilic groups and compounds can also be found in <CIT> For example, an ampholyte compound represented by the general formula:
<CHM>.

Suitable non-fouling compounds include (poly(ethylene glycol) and methoxy ether poly(ethylene glycol)), methacryloyloxyethyl phosphorylcholine, and <NUM>-((<NUM>-(methacryloyloxy)ethyl)dimethylammonio)ethyl <NUM>-methoxyethyl phosphate), and other agents that prevent the laying down and adhesion of biological and chemical entities on to a surface. Numerous examples are known in the art.

Therapeutic agents can be blended with the polymer coating to allow for the localized delivery of bioactive compounds.

In some embodiments the anti-microbial monomer takes the structure depicted in structures <NUM> or <NUM> below. In some embodiments of structures <NUM> and <NUM>, n is from <NUM> to <NUM>, p is from <NUM> to <NUM>. X is a methyl or hydrogen. In further embodiments n may be from <NUM> to <NUM>. In further embodiments p may be from <NUM> to <NUM>. These ranges may be combined. <CHM>
<CHM>.

In some embodiments the anti-microbial monomer takes the structure depicted in structure <NUM>. In some embodiments of structure <NUM>, n is from <NUM> to <NUM>, m is from <NUM> to <NUM>, and p is from <NUM> to <NUM>. X is a methyl or hydrogen. In further embodiments n may be from <NUM> to <NUM>. In further embodiments m may be from <NUM> to <NUM>. In further embodiments p may be from <NUM> to <NUM>. These ranges may be combined.

In some embodiments the anti-microbial monomer takes the structure depicted in structure <NUM>. In some embodiments of structure <NUM>, n is from <NUM> to <NUM>, m is from <NUM> to <NUM>, p is from <NUM> to <NUM>, and r is from <NUM> to <NUM>. X is a methyl or hydrogen. Y is a substituted or unsubstituted hydrocarbon chain that may or may not contain heteroatoms. In further embodiments n may be from <NUM> to <NUM>. In further embodiments m may be from <NUM> to <NUM>. In further embodiments p may be from <NUM> to <NUM>. In further embodiments r may be from <NUM> to <NUM>. These ranges may be combined.

In some embodiments the antithrombogenic monomer takes the structure depicted in structure <NUM>. In some embodiments of structure <NUM>, n is from <NUM> to <NUM>. X is a methyl or hydrogen. Y is a heteroatom, a nitrogen, or an oxygen atom. R<NUM> and R<NUM> are substituted or unsubstituted hydrocarbon chains that may or may not contain heteroatoms. In certain embodiments Y may be omitted entirely. In further embodiments n may be from <NUM> to <NUM>. In further embodiments Heparin may be benzalkonium heparin, heparin sulfate, heparan sulfate, heparin ammonium, heparin benzyl ester, heparin calcium, heparin lithium, heparin sodium. Heparin may be replaced by derivatives of heparin including heparin methacrylate, heparin quaternary ammonium salt complex methacrylate, heparin methacrylate salt, and heparin polyethylene glycol methacrylate or other glycosaminoglycans including dermatan sulfate, chondroitin sulfate, keratan sulfate, and hyaluronic acid.

In some embodiments the antithrombogenic monomer takes the structure depicted in structure <NUM>. X is a methyl or hydrogen. Y is a substituted or unsubstituted hydrocarbon chain that may or may not contain heteroatoms. In further embodiments Heparin may be benzalkonium heparin, heparin sulfate, heparan sulfate, heparin ammonium, heparin benzyl ester, heparin calcium, heparin lithium, heparin sodium. Heparin may be replaced by derivatives of heparin including heparin methacrylate, heparin quaternary ammonium salt complex methacrylate, heparin methacrylate salt, and heparin polyethylene glycol methacrylate or other glycosaminoglycans including dermatan sulfate, chondroitin sulfate, keratan sulfate, and hyaluronic acid. <CHM>
The following non-limiting Examples illustrate different aspects of the invention.

<NUM> of carbonyl diimidazole (CDI) was dissolved in <NUM> anhydrous dichloromethane in a <NUM> conical flask. <NUM> of poly(ethylene glycol) methacrylate was dissolved in <NUM> of anhydrous dichloromethane, the mixture was blended into a <NUM> dropping funnel and added drop wise to the CDI in the conical flask at room temperature over a period of approximately <NUM> hour. The mixture was left to stir for an additional <NUM> hours. Then, the dichloromethane was removed under rotary evaporation.

<NUM> of sodium heparin (<NUM>-<NUM> kDa) was dissolved in <NUM> of pure water. In the conical flask, <NUM> of pure water was added to the CDI-activated poly(ethylene glycol) methacrylate from above. The mixture was then added to the aqueous solution of sodium heparin and left to stir at room temperature for <NUM> hours.

After the <NUM> hour period, the heparin mixture was precipitated twice in tetrahydrofuran and twice in acetone.

The poly(ethylene glycol) methacrylate-derivatized heparin was then dried in a vacuum oven in small pellets for <NUM> hours at ~ <NUM>-<NUM>.

Alternatively, the pH of the solution can be adjusted to <NUM>-<NUM> once the heparin and CDI-activated poly(ethylene glycol) methacrylate are mixed together. Then, the pH can be readjusted to <NUM> once the reaction is finished.

<NUM> of sodium heparin was dissolved in <NUM> of water. <NUM> of benzalkonium chloride was dissolved in <NUM> water.

Once totally dissolved and cooled down, the benzalkonium chloride solution was added to the sodium heparin aqueous solution to precipitate the heparin-benzalkonium complex.

The white precipitate was stirred for <NUM> minutes and then left to stand.

The white precipitate was filtered and washed with water thoroughly in order to remove any water soluble starting materials.

The white precipitate was dissolved in isopropanol and re-precipitated in water, filtered and washed thoroughly with water.

The precipitate was suspended in water and dialysed in water at a molecular weight cut off of <NUM> Daltons and then freeze-dried to recover a white powder of sodium heparin-benzalkonium complex.

The heparin poly(ethylene glycol) methacrylate from example <NUM> can also be complexed with benzalkonium chloride using the same method as above.

The heparin poly(ethylene glycol) methacrylate-benzalkonium complex or heparin methacrylate-benzalkonium complex was introduced in an aqueous sodium chloride solution (<NUM>). Overtime, the solid dissolved. Once dissolved, the aqueous solution was precipitated from acetone and further washed with acetone to isolate the decomplexed heparin poly(ethylene glycol) methacrylate or heparin methacrylate.

The white precipitate was dried in a vacuum oven.

Poly(hexanide) hydrochloride was dialysed against water at a molecular weight cut off of <NUM> Daltons. <NUM> of dialysed poly(hexanide) in aqueous solution (~<NUM> of solution) was then neutralised with a solution of <NUM> of sodium hydroxide dissolved in <NUM> of water. Aqueous sodium hydroxide was slowly added (<NUM>/min) to the aqueous dialysed poly(hexanide). After the addition, the neutralised solution was frozen and ultimately freeze-dried to obtain a white powder of neutralised poly(hexanide).

<NUM> of neutralised poly(hexanide) was dissolved in <NUM> of water. <NUM> of methacryloyl chloride was added to the solution and left to stir for a minimum of <NUM> hour, until the pH was <NUM> and the solution was totally clear.

The aqueous mixture was precipitated twice in tetrahydrofuran and washed twice in acetone. The precipitate was dried in a vacuum oven at <NUM> for <NUM>-<NUM> hours to obtain a white powder.

<NUM> of sodium hydroxide was dissolved in <NUM> of water. The mixture was stirred and left to cool down to room temperature.

<NUM> of poly(ethylene glycol) methacrylate was added to the above mixture and left to stir for ~ <NUM> hours.

<NUM> of epichlorohydrin was blended in a flask and the poly(ethylene glycol) methacrylate solution from above was blended in a dropping funnel and slowly added to the flask containing epichlorohydrin. The addition was completed over a period of ~ <NUM> hours <NUM> minutes.

The reaction mixture was then stirred at <NUM> for <NUM> hours.

After the <NUM> hour period, the water mixture was washed with diethyl ether via extraction. Then, the water layer was extracted with dichloromethane. The dichloromethane fraction was dried over a desiccant and the dichloromethane was evaporated using a rotary evaporator to yield a transparent oil of epoxy-poly(ethylene glycol) methacrylate.

<NUM> of neutralised poly(hexanide) (as per example <NUM>) was dissolved in <NUM> of water. <NUM> of the epoxy-poly(ethylene glycol) methacrylate was added to the neutralised poly(hexanide). The mixture was stirred at ~ <NUM> overnight (~ <NUM> hours).

After the <NUM> hour period, the mixture was precipitated twice in tetrahydrofuran and washed twice in acetone. The white paste was dissolved in a little amount of water, frozen and ultimately freeze-dried to obtain a white powder of poly(ethylene glycol) methacrylate poly(hexanide).

<NUM> of chlorhexidine was dissolved in <NUM> anhydrous dichloromethane. <NUM> (<NUM>µL) of <NUM>-isocyanatoethyl methacrylate was dissolved in <NUM> of anhydrous dichloromethane and was added drop wise to the chlorhexidine solution. Infrared was used to follow the disappearance of the isocyanate functionality. Once the isocyanate had totally disappeared, the dihydrochloride of the resulting product was formed by adding <NUM> of HCl (<NUM>) in <NUM>,<NUM>-dioxane. Then, the reaction mixture was evaporated to yield chlorhexidine dihydrochloride methacrylate.

<NUM> of chlorhexidine was dissolved in <NUM> of anhydrous dichloromethane. <NUM> (<NUM>µL) of methacryloyl chloride was dissolved in <NUM> of anhydrous dichloromethane and was added dropwise to the chlorhexidine solution. The reaction was left to stir for <NUM>-<NUM> hours. The dihydrochloride was formed by adding <NUM> of HCl (<NUM>) in <NUM>,<NUM>-dioxane. Then, the reaction mixture was evaporated to yield the chlorhexidine dihydrochloride methacrylate.

Chlorhexidine digluconate can be used instead of chlorhexidine.

In a round-bottom flask, equipped with a condenser, a thermometer and a Pasteur pipette attachment to nitrogen inlet, <NUM> of heparin poly(ethylene glycol) methacrylate (as per example <NUM>) was dissolved in <NUM> of water. Subsequently, the following components were added into the flask: <NUM> (solid) of methoxy poly(ethylene glycol) methacrylate of MW <NUM>, purified on charcoal and diluted at <NUM>% (w/v), <NUM> of methoxy poly(ethylene glycol) methacrylate of MW <NUM>, <NUM> of methacrylic acid, <NUM> of butyl methacrylate and <NUM> of isopropanol. The reflux condenser was turned on, the nitrogen allowed to bubble into the mixture of monomers and the heating turned up to warm up the mixture of monomers.

In a separate vial, <NUM> of poly(ethylene glycol) methacrylate-poly(hexanide) (from example <NUM>) was dissolved in <NUM> of water. In yet another vial, <NUM> of potassium persulfate was dissolved in <NUM> of water and degassed with nitrogen.

Once the mixture had reached a temperature of <NUM>, the potassium persulfate aqueous solution was added to the mixture of monomers in the round bottom flask and the polymerisation started.

The poly(ethylene glycol) methacrylate-poly(hexanide) aqueous solution was then added. The polymerisation was allowed to progress for a total of <NUM>-<NUM> minutes and was quenched by adding <NUM> of icy cold water. The polymerisation solution was allowed to cool down to room temperature and was dialysed at a molecular weight cut off of <NUM>-<NUM> KDa against water overnight.

The polymer from example <NUM> in which methacrylic acid is replaced by <NUM>-benzoylphenyl methacrylate (<NUM>) during the synthesis, or in which both methacrylic acid and <NUM>-benzoylphenyl methacrylate are jointly used.

In a separate vial, <NUM> of poly(hexanide) methacrylate (from example <NUM>) was dissolved in <NUM> of water. In yet another vial, <NUM> of potassium persulfate was dissolved in <NUM> of water and degassed with nitrogen.

The poly(hexanide) methacrylate aqueous solution was then added. The polymerisation was allowed to progress for a total of <NUM>-<NUM> minutes and was quenched by adding <NUM> of icy cold water. The polymerisation solution was allowed to cool down to room temperature and was dialysed at a molecular weight cut off of <NUM>-<NUM> KDa against water overnight.

In a separate vial, <NUM> of chlorhexidine dihydrochloride methacrylate was dissolved in <NUM> of isopropanol. In yet another vial, <NUM> of potassium persulfate was dissolved in <NUM> of water and degassed with nitrogen.

The chlorhexidine dihydrochloride methacrylate aqueous solution was then added. The polymerisation was allowed to progress for a total of <NUM>-<NUM> minutes and was quenched by adding <NUM> of icy cold water. The polymerisation solution was allowed to cool down to room temperature and was dialysed at a molecular weight cut off of <NUM>-<NUM> KDa against water overnight.

In a round-bottom flask, equipped with a condenser, a thermometer and a Pasteur pipette attachment to nitrogen inlet, <NUM> of poly(ethylene glycol) methacrylate poly(hexanide) was blended with <NUM> (solid) of methoxy poly(ethylene glycol) methacrylate of MW <NUM>, purified on charcoal and diluted at <NUM>% (w/v), <NUM> of methoxy poly(ethylene glycol) methacrylate of MW <NUM>, <NUM> of methacrylic acid, <NUM> of butyl methacrylate and <NUM> of isopropanol. The reflux condenser was turned on, the nitrogen allowed to bubble into the mixture of monomers and the heating turned up to warm up the mixture of monomers. In a separate vial, <NUM> of heparin poly(ethylene glycol) methacrylate/benzalkonium complex (as per example <NUM>) was dissolved in <NUM> of isopropanol. In yet another vial, <NUM> of potassium persulfate was dissolved in <NUM> of water and degassed with nitrogen.

Once the mixture in the round bottom flask had reached a temperature of <NUM>, the potassium persulfate aqueous solution was added to the mixture of monomers in the round bottom flask and the polymerisation started.

The heparin poly(ethylene glycol) methacrylate/benzalkonium complex solution was then added. The polymerisation was allowed to progress for approximately <NUM> hour and was then allowed to cool down to room temperature.

The heparin/benzalkonium complex, incorporated in the polymer backbone, can be decomplexed after coating on a device as described in example <NUM> or can be decomplexed in solution after polymerisation using a sodium chloride aqueous solution.

The polymerisation solution was dialysed at a molecular weight cut off of <NUM>-<NUM> KDa against water overnight.

In a round-bottom flask, equipped with a condenser, a thermometer and a Pasteur pipette attachment to nitrogen inlet, <NUM> of poly(ethylene glycol) methacrylate poly(hexanide) was blended and dissolved in <NUM> of water. <NUM> (solid) of methoxy poly(ethylene glycol) methacrylate of MW <NUM>, purified on charcoal and diluted at <NUM>% (w/v), was added with <NUM> of methoxy poly(ethylene glycol) methacrylate of MW <NUM>, <NUM> of methacrylic acid, <NUM> of butyl methacrylate and <NUM> of isopropanol. The reflux condenser was turned on, the nitrogen allowed to bubble into the mixture of monomers and the heating turned up to warm up the mixture of monomers.

In a separate vial, <NUM> of potassium persulfate was dissolved in <NUM> of water and degassed with nitrogen.

The polymerisation was allowed to progress to the desired level of viscosity and was quenched by the addition of <NUM> of icy cold water. Once cooled down to room temperature, the polymerisation solution was dialysed at a molecular weight cut off of <NUM>-<NUM> KDa against water overnight.

In a round-bottom flask, equipped with a condenser, a thermometer and a Pasteur pipette attachment to nitrogen inlet, <NUM> of heparin poly(ethylene glycol) methacrylate was blended and dissolved with <NUM> of water. <NUM> (solid) of methoxy poly(ethylene glycol) methacrylate of MW <NUM>, purified on charcoal and diluted at <NUM>% (w/v), was added to the flask with <NUM> of methoxy poly(ethylene glycol) methacrylate of MW <NUM>, <NUM> of methacrylic acid, <NUM> of butyl methacrylate and <NUM> of isopropanol. The reflux condenser was turned on, the nitrogen allowed to bubble into the mixture of monomers and the heating turned up to warm up the mixture of monomers.

The polymerisation was allowed to progress for approximately <NUM> hour to the desired level of viscosity and was then allowed to cool down to room temperature. The polymerisation solution was dialysed at a molecular weight cut off of <NUM>-<NUM> KDa against water overnight.

The polymers from examples <NUM> and <NUM> in which methacrylic acid is replaced by <NUM>-benzoylphenyl methacrylate (<NUM>) during the synthesis, or in which both methacrylic acid and <NUM>-benzoylphenyl methacrylate are jointly used.

The polymers from examples <NUM>, <NUM>, and <NUM> in which heparin poly(ethylene glycol) methacrylate may be replaced by benzalkonium-heparin methacrylate complex or benzalkonium-heparin poly(ethylene glycol) methacrylate complex.

A formulation was prepared as follows (% volume):.

The device was dip-coated in the coating formulation, the film was left to dry at room temperature for approximately <NUM> minutes and then was cured at <NUM> for <NUM> hour.

The device was dip-coated in the coating formulation, the film was left to dry at room temperature for approximately <NUM> minutes. The film was firstly cured using UV light (<NUM> seconds), followed by a <NUM> hour cure at <NUM> to provide a strong and stable coating.

The device was dip-coated in the coating formulation, the film was left to dry at room temperature for approximately <NUM> minutes and then was cured at <NUM> for <NUM> hour. The coated device was then left in a phosphate buffered saline solution for <NUM> to decomplex the salt, then rinse in water thoroughly to remove any remaining salt.

In a Falcon tube, <NUM> of isopropanol was blended with <NUM> of tetrahydrofuran. <NUM> of the antimicrobial polymer from example <NUM> was blended with <NUM> of the anti-coagulant polymer from example <NUM>. <NUM>µL of polyaziridine crosslinker at <NUM>% (w/v) was added, the solution was mixed well and left to settle.

In a Falcon tube, <NUM> of isopropanol was blended with <NUM> of tetrahydrofuran. <NUM> of the antimicrobial polymer from example <NUM> was added and <NUM>µL of polyaziridine crosslinker at <NUM>% (w/v) was added, the solution was mixed well and left to settle.

In a Falcon tube, <NUM> of isopropanol was blended with <NUM> of tetrahydrofuran. <NUM> of the anticoagulant polymer from example <NUM> was added and <NUM>µL of polyaziridine crosslinker at <NUM>% (w/v) was added, the solution was mixed well and left to settle.

Test pieces are exposed to a particular medium (to enable protein adhesion etc.) such as plasma, blood or urine etc. for a predetermined time point, pieces are then washed then put into the test protocol. The test protocol effectively incubated the device with live microorganisms, washed device to removed "solution present bacteria", allowed active component sufficient time to "kill" then transferred to growth media where viable microorganisms on the device will proliferate into daughter cells in solution hence increasing turbidity of growth media which can then be measured by optical density.

Colonies of each relevant bacteria (Oxoid, UK) were transferred from cultures on agar slopes (Oxoid, UK) to tryptone soya broth (TSB) (Oxoid, UK) and incubated at <NUM> ° C overnight. A second, bacteria-free control volume was also incubated at <NUM> ° C.

Bacterial cultures and cultured controls were checked for turbidity, this was observable in cultures but controls were unclouded. A volume of <NUM> % (v/v) TSB in isotonic saline was prepared in a sterile container and placed at <NUM> ° C.

Following this the coated and uncoated articles (cut to suitable assay dimensions as necessary) were placed in fresh de-ionised sterile water (Baxter, UK) for <NUM> mins at ambient temperature to hydrate the coating. Where the article was a tube, such as a catheter, the lumens were flooded using a disposable syringe (Midmeds, UK) which remained attached to the article throughout the hydration process. All handling of test surfaces was performed with sterile tweezers.

During the hydration stage the population density (CFU/ml) of each culture was assessed using a process akin to the McFarland Turbidity Standards, read at <NUM>. Once the absorbance was read, an appropriate volume of <NUM> x <NUM><NUM> CFU/ml bacterial suspension was prepared in the <NUM> % (v/v) TSB. This challenge suspension is then transferred to sterile glass/plasticware of appropriate dimensions/volume to accommodate the test article.

The test articles were then rinsed with deionised sterile water and placed in the challenge suspension. Again, where the article is a tube, care is taken to ensure the exposure of the lumens. The test articles are then incubated for <NUM> mins at <NUM> ° C. Gentle manual agitation was applied at <NUM> mins to dislodge any bubbles that formed on the device surface.

Following the challenge incubation, articles were removed from the suspension and rinsed thoroughly with isotonic saline. Where secondary articles such as syringes or needles were attached to the test items, these were discarded and if necessary replaced with fresh sterile items. Where the test item is a tube such as a catheter, a <NUM> disposable syringe (plunger removed) is used as a funnel to rinse the lumens.

The test articles are then placed in an isotonic saline "soak" for <NUM> mins at ambient temperature, then rinsed a second time, and placed in a second soak for <NUM> mins, during which time a volume of <NUM> % (v/v) TSB in isotonic saline was prepared, measured out into culture dishes (<NUM> - <NUM> well as appropriate for the test item in question) (Griener Bio-One, UK) and brought to ambient temperature. A number of wells containing <NUM> % TSB were reserved as device-free controls. After the second soak, test articles were subjected to a final rinse. Where secondary articles were present they were again discarded. Following this rinse the test items were either transferred whole to the <NUM> % TSB solutions, or if appropriate cleaved into sections (using sterile razor blades and sterile foil) and these sections then transferred into the <NUM> % TSB solution. When the items were cleaved into sections, the uppermost and lowermost sections were discarded. Where the test articles were tubes, a <NUM>-<NUM>µl pipette (Eppendorf, UK) and sterile tips (Griener Bio-One, UK) were used as necessary to flush air bubbles from the lumens of the sections immersed in <NUM>% TSB.

The test items and device-free control wells are incubated at ambient temperature overnight.

The culture plates containing the test items were visually examined for signs of growth in either the test item wells, or the control (device-free) wells. The plates were then sealed with film and placed at <NUM> ° C, and assessed visually ever hour for signs of growth. Turbidity typically presented after > <NUM> hours at <NUM> ° C after overnight incubation at RT, though inter-species and inter-device variation did occur). When wells containing uncoated articles exhibited strong signs of bacterial growth their contents were resuspended fully using disposable Pasteur pipettes, and then <NUM>µl transferred from each well to <NUM> well plates (in triplicate) before the plate(s) were read at <NUM>.

Test pieces may (or may not be) exposed to a particular medium (to enable protein adhesion etc) such as plasma, blood or urine etc for a predetermined time point, pieces are then washed then put into the test protocol.

Venous blood was collected from healthy human volunteers (who denied taking any medication for six weeks). Briefly, after venipuncture, <NUM> of blood was collected and discarded. <NUM> of blood was then collected and anticoagulated using citrate phosphate dextrose (CPD)This was then split into two aliquots of <NUM> and of <NUM> of platelet rich plasma (PRP) and platelet poor plasma (PPP) were prepared by centrifugation. The platelet count was then taken using a haemocytometer and light microscope utilising phase contrast.

The PRP was then adjusted to 1x10<NUM> platelets/ µL using PPP as a diluent.

For the experiments <NUM>µL of the 1x10<NUM> platelets/ µL PRP from above was transferred to the middle of coated coverslip and left (covered to prevent evaporation) at <NUM> for half an hour. After this time point the slides were then rinsed three times in saline then fixed overnight in <NUM>% glutaric dialdehyde (Sigma Aldrich) in PBS (Sigma Aldrich). They were then examined by light microscopy at x <NUM> and the amount of platelets in the field of view counted.

Demonstrative photos were then taken using an inverted microscope and camera (both Motic Instruments).

Test pieces may (or may not be) exposed to a particular medium (to enable protein adhesion etc) such as plasma, blood or urine etc for a predetermined time point, pieces are then washed and put into the test protocol.

Using a commercially available anti-IIa heparin kit (Hyphen Biomed via UK distributor Quadratech Diagnostics) the heparin activity of the device surface was measured via anti IIa inhibition.

Briefly; using a heparin reference material (Celsus laboratories) a calibration curve of heparin was prepared in physiological saline (<NUM>/L NaCl (Sigma Aldrich)) containing <NUM>% Bovine Serum Albumin ("BSA" Sigma Aldrich), as shown in Table <NUM>.

The reagents were then made as to the manufacturer's instructions and the test started (as per the manufacturer's instructions).

To a series of test tubes at <NUM>, the following was added:.

This was then mixed and incubated at <NUM> for <NUM>-<NUM> minutes then <NUM>µL Human Thrombin (Preincubated at <NUM>) was added. This was then mixed and incubated at <NUM> for exactly <NUM> minutes. Reaction was then stopped using Citric Acid (<NUM>/L Sigma Aldrich). The acid was mixed in then absorbance at <NUM> was measured on a spectrophotometer (Perkin Elmer) against a blank prepared by mixing the above reagents in reverse order. A calibration curve was then prepared and linear regression was used for interpolation of heparin level on surface (acceptable if r<NUM>><NUM>).

Catheters were coated as per the methodology set out in the relevant example (i.e. examples <NUM>-<NUM>) and then tested for antimicrobial activity against Pseudomonas aeruginosa as per example <NUM>.

The turbidity results obtained are shown below in Table <NUM> and <FIG>.

Catheters were coated as per the methodology set out in the relevant example (i.e. examples <NUM>-<NUM>) and then tested for antimicrobial activity against Enterococcus faecalis as per example <NUM>.

The turbidity results obtained are shown below in Table <NUM> and in <FIG>.

Catheters were coated as per the methodology set out in the relevant example (i.e. examples <NUM>-<NUM>) and then tested for antimicrobial activity against Escherichia coli as per example <NUM>. Prior to testing the sections were incubated in citrated human plasma overnight.

Catheters were coated as per the methodology set out in the relevant example (i.e. examples <NUM>-<NUM>) and then tested for antimicrobial activity against Staphylococcus aureus as per example <NUM>. Prior to testing the sections were incubated in citrated human plasma overnight.

Transparent samples were coated as per the methodology set out in the relevant example (i.e. examples <NUM>-<NUM>). Platelet adhesion was then calculated by the methodology in Example <NUM>. The results obtained are below in Table <NUM> and <FIG>. <FIG> represents the polyurethane substrate (x400), and <FIG> a combination polymer (high heparin) from Example <NUM> (also a x400 photomicrograph).

Polyurethane sections were coated as per the methodology set out in the relevant example (i.e. examples <NUM>-<NUM>).

Pieces were then incubated in PBS at <NUM> and at set time points the heparin activity of pieces was measured using the methodology in example <NUM>.

The results obtained are below in Table <NUM> and <FIG>.

<NUM> of Polyhexamethylene Guanidine Hydrochloride (PHMG, Chemos GmBH) in aqueous solution (~<NUM> of solution) was neutralised with a solution of <NUM> of sodium hydroxide dissolved in <NUM> of water. Aqueous sodium hydroxide was slowly added (<NUM>/min) to the aqueous PHMG.

After the addition, the neutralised solution was frozen and ultimately freeze-dried to obtain a white powder of neutralised PHMG.

<NUM> of neutralised PHMG was dissolved in <NUM> of water. <NUM> of methacryloyl chloride was added to the solution and left to stir for a minimum of <NUM> hour, until the pH was <NUM> and the solution was totally clear.

In a separate vial, <NUM> of PHMG-MA (from example <NUM>) was dissolved in <NUM> of water. In yet another vial, <NUM> of potassium persulfate was dissolved in <NUM> of water and degassed with nitrogen.

The PHMG-MA aqueous solution was then added. The polymerisation was allowed to progress for a total of <NUM>-<NUM> minutes and was quenched by adding <NUM> of icy cold water. The polymerisation solution was allowed to cool down to room temperature and was dialysed at a molecular weight cut off of <NUM>-<NUM> KDa against water overnight.

In a round-bottom flask, equipped with a condenser, a thermometer and a Pasteur pipette attachment to nitrogen inlet, <NUM> of poly of PHMG-MA (from Example <NUM>) was blended and dissolved in <NUM> of water. <NUM> (solid) of methoxy poly(ethylene glycol) methacrylate of MW <NUM>, purified on charcoal and diluted at <NUM>% (w/v), was added with <NUM> of methoxy poly(ethylene glycol) methacrylate of MW <NUM>, <NUM> of methacrylic acid, <NUM> of butyl methacrylate and <NUM> of isopropanol. The reflux condenser was turned on, the nitrogen allowed to bubble into the mixture of monomers and the heating turned up to warm up the mixture of monomers.

<NUM> of poly(ethylene glycol) methacrylate was added to the above mixture and left to stir for - <NUM> hours.

<NUM> of epichlorohydrin was blended in a flask and the poly(ethylene glycol) methacrylate solution from above was blended in a dropping funnel and slowly added to the flask containing epichlorohydrin. The addition was completed over a period of - <NUM> hours <NUM> minutes.

<NUM> of neutralised PHMG (as per example <NUM>) was dissolved in <NUM> of water. <NUM> of the epoxy-poly(ethylene glycol) methacrylate was added to the neutralised poly(hexanide). The mixture was stirred at - <NUM> overnight (~ <NUM> hours).

After the <NUM> hour period, the mixture was precipitated twice in tetrahydrofuran and washed twice in acetone. The white paste was dissolved in a little amount of water, frozen and ultimately freeze-dried to obtain a white powder of poly(ethylene glycol) methacrylate PHMG.

In a separate vial, <NUM> of poly(ethylene glycol) methacrylate PHMG (from example <NUM>) was dissolved in <NUM> of water. In yet another vial, <NUM> of potassium persulfate was dissolved in <NUM> of water and degassed with nitrogen.

The poly(ethylene glycol) methacrylate PHMG aqueous solution was then added. The polymerisation was allowed to progress for a total of <NUM>-<NUM> minutes and was quenched by adding <NUM> of icy cold water. The polymerisation solution was allowed to cool down to room temperature and was dialysed at a molecular weight cut off of <NUM>-<NUM> KDa against water overnight.

In a round-bottom flask, equipped with a condenser, a thermometer and a Pasteur pipette attachment to nitrogen inlet, <NUM> of poly(ethylene glycol) methacrylate PHMG (from Example <NUM>) was blended and dissolved in <NUM> of water. <NUM> (solid) of methoxy poly(ethylene glycol) methacrylate of MW <NUM>, purified on charcoal and diluted at <NUM>% (w/v), was added with <NUM> of methoxy poly(ethylene glycol) methacrylate of MW <NUM>, <NUM> of methacrylic acid, <NUM> of butyl methacrylate and <NUM> of isopropanol. The reflux condenser was turned on, the nitrogen allowed to bubble into the mixture of monomers and the heating turned up to warm up the mixture of monomers.

Claim 1:
An anti-microbial polymer which is a copolymer of
(a) an anti-microbial monomer consisting of a polymerizable group that is connected to a guanide or biguanide antimicrobial agent by a polyethylene oxide attachment group; and
(b) one or more co-monomers which are capable of undergoing free radical polymerisation, selected from acrylates, methacrylates, (meth)acrylic acid, <NUM>-hydroxyethyl methacrylate, hydroxypropyl methacrylate, n-butyl methacrylate, tert-butyl methacrylate, n-hexyl methacrylate, <NUM>-methoxyethyl methacrylate, and monomers comprising poly(ethylene glycol).