US20100135949A1 - Antimicrobial compositions - Google Patents

Abstract

Antimicrobial compositions and methods are disclosed. The antimicrobial compositions are particularly useful in providing antimicrobial capability to a wide-range of medical devices. In one aspect the invention relates a UV curable antimicrobial coating comprising a UV curable composition comprising an oligomer, a momoner, and a photoinitiator which are together capable of forming a UV curable polymer composition. The compositions include rheology modifiers as necessary. The compositions also include antimicrobial agents, which may be selected from a wide array of agents. Representative antimicrobial agents include cetyl pyridium chloride, cetrimide, alexidine, chlorexidine diacetate, benzalkonium chloride, and o-phthalaldehyde.

Description

RELATED APPLICATIONS
• This application claims priority to U.S. provisional patent application No. 61/118,988, filed Dec. 1, 2008, entitled “Antimicrobial Compositions and Methods for Medical Product Use,” which application is incorporated herein by this reference.
BACKGROUND OF THE INVENTION
• The present invention relates to antimicrobial compositions and methods for use of those compositions in various medical applications. One of the major challenges of modern medical treatment is control of infection and the spread of microbial organisms.
• One area where this challenge is constantly presented is in infusion therapy of various types. Infusion therapy is one of the most common health care procedures. Hospitalized, home care, and other patients receive fluids, pharmaceuticals, and blood products via a vascular access device inserted into the vascular system. Infusion therapy may be used to treat an infection, provide anesthesia or analgesia, provide nutritional support, treat cancerous growths, maintain blood pressure and heart rhythm, or many other clinically significant uses.
• Infusion therapy is facilitated by a vascular access device. The vascular access device may access a patient's peripheral or central vasculature. The vascular access device may be indwelling for short term (days), moderate term (weeks), or long term (months to years). The vascular access device may be used for continuous infusion therapy or for intermittent therapy.
• A common vascular access device is a plastic catheter that is inserted into a patient's vein. The catheter length may vary from a few centimeters for peripheral access, to many centimeters for central access and may included devices such as peripherally inserted central catheters (PICC). The catheter may be inserted transcutaneously or may be surgically implanted beneath the patient's skin. The catheter, or any other vascular access device attached thereto, may have a single lumen or multiple lumens for infusion of many fluids simultaneously.
• The vascular access device commonly includes a Luer adapter to which other medical devices may be attached. For example, an administration set may be attached to a vascular access device at one end and an intravenous (IV) bag at the other. The administration set is a fluid conduit for the continuous infusion of fluids and pharmaceuticals. Commonly, an IV access device is a vascular access device that may be attached to another vascular access device, closes the vascular access device, and allows for intermittent infusion or injection of fluids and pharmaceuticals. An IV access device may include a housing and a septum for closing the system. The septum may be opened with a blunt cannula or a male Luer of a medical device.
• When the septum of a vascular access device fails to operate properly or has inadequate design features, certain complications may occur. Complications associated with infusion therapy may cause significant morbidity and even mortality. One significant complication is catheter related blood stream infection (CRBSI). An estimate of 250,000-400,000 cases of central venous catheter (CVC) associated BSIs occur annually in US hospitals. Attributable mortality is an estimated 12%-25% for each infection and a cost to the health care system of $25,000-$56,000 per episode.
• A vascular access device may serve as a nidus of infection, resulting in a disseminated BSI (blood stream infection). This may be caused by failure to regularly flush the device, a non-sterile insertion technique, or by pathogens that enter the fluid flow path through either end of the path subsequent to catheter insertion. When a vascular access device is contaminated, pathogens adhere to the vascular access device, colonize, and form a biofilm. The biofilm is resistant to most biocidal agents and provides a replenishing source for pathogens to enter a patient's bloodstream and cause a BSI. Thus, devices with antimicrobial properties are needed.
• One approach to preventing biofilm formation and patient infection is to provide an antimicrobial coating on various medical devices and components. Many medical devices are made with either metallic or polymeric materials. These materials usually have a high coefficient of friction. A low molecular weight material or liquid with a low coefficient of friction is usually compounded into the bulk of the materials or coated onto the surface of the substrates to help the functionality of the devices.
• Over the last 35 years, it has been common practice to use a thermoplastic polyurethane solution as the carrier for antimicrobial coatings. The solvent is usually tetrahydrofuran (THF), dimethylformamide (DMF), or a blend of both. Because THF can be oxidized very quickly and tends to be very explosive, an expensive explosion-proof coating facility is necessary. These harsh solvents also attack many of the polymeric materials commonly used, including polyurethane, silicone, polyisoprene, butyl rubber polycarbonate, rigid polyurethane, rigid polyvinyl chloride, acrylics, and styrene-butadiene rubber (SBR). Therefore, medical devices made with these materials can become distorted over time and/or form microcracks on their surfaces. Another issue with this type of coating is that it takes almost 24 hours for the solvent to be completely heat evaporated. Accordingly, conventional technology has persistent problems with processing, performance, and cost.
• Another limitation is the availability of suitable antimicrobial agents for use in such coatings. One of the most commonly used antimicrobial agents used in coating medical device is silver. Silver salts and silver element are well known antimicrobial agents in both the medical surgical industry and general industries. They are usually incorporated into the polymeric bulk material or coated onto the surface of the medical devices by plasma, heat evaporation, electroplating, or by conventional solvent coating technologies. These technologies are tedious, expensive, and not environmentally friendly.
• In addition, the performance of silver coated medical devices is mediocre at best. For example, it can take up to eight (8) hours before the silver ion, ionized from the silver salts or silver element, to reach efficacy as an antimicrobial agent. As a result, substantial microbial activity can occur prior to the silver coating even becoming effective. Furthermore, the silver compound or silver element has an unpleasant color, from dark amber to black.
• Accordingly, there is a need in the art for improved compositions for providing antimicrobial capability to medical devices of various types, and particularly devices related to infusion therapy. Specifically, there is a need for an effective antimicrobial coating that can be easily applied to medical devices constructed of polymeric materials and metals. There is also a need for improved methods of applying such antimicrobial coatings to medical devices.
BRIEF SUMMARY OF THE INVENTION
• The present invention has been developed in response to problems and needs in the art that have not yet been fully resolved by currently available antimicrobial compositions and methods. Thus, these compositions and methods are developed to reduce complications, such as the risk and occurrence of CRBSIs, by providing improved antimicrobial compositions and methods for use in conjunction with medical devices.
• The present invention relates to ultraviolet (UV) (wavelength of approximately 200 nm to 600 nm)-curable coatings that have antimicrobial properties. The coatings may be cured by light in the range set forth above, namely from about 200 nm to about 600 nm. In some embodiments, it may be preferable to cure the composition with light in the range of from about 300 nm to about 450 nm. These coatings are particularly adaptable for use on medical devices, particularly intravascular access devices like needleless valves. As mentioned above, the medical devices are often comprised of polymeric substrates, especially polycarbonate (PC), polyurethane (PU), polyvinyl chloride (PVC), styrene-butadiene rubber (SBR), and acrylics.
• In one aspect of the invention the surfaces of such devices are coated with a UV-curable coating (sometimes hereinafter referred to as “UV coating”) which comprises a UV curable composition and addition components incorporated therein such as antimicrobial agents uniformly distributed throughout its matrix. The antimicrobial agents are able to diffuse through the matrix and kill microscopic organisms that come in contact with the coating surface. The antimicrobial agents, which are uniformly distributed in the UV coating matrix, gradually diffuse out of the matrix when the matrix is softened by IV fluids. The antimicrobial agents are then available to kill the microbes that come in contact with the coating surface.
• The formulations of this invention are generally comprised of a combination of urethane or polyester-type oligomer with acrylate-type functional groups, acrylate-type monomers, photoinitiators, rheological modifiers, and antimicrobial agents. The nano- or micro-sized particles of the antimicrobial agents are uniformly and permanently distributed throughout the whole coating matrix.
• The coatings are solventless and can be sprayed, wiped, dipped or distributed by using other conventional coating methods to coat a substrate's surface. They can then be rapidly cured with ultraviolet light. Curing may be completed in seconds or minutes depending on the formulation and curing conditions. The coatings of the present invention are generally efficacious within minutes instead of hours as with conventional coatings. The coatings also generally have a pleasant light color or an even clear color.
• A wide variety of oligomers can be used within the scope of the present invention. It is only necessary that the oligomer be capable of UV curing and of carrying antimicrobial agents of the type described herein. For example, the oligomers can be acrylated aliphatic urethanes, acrylated aromatic urethanes, acrylated polyesters, unsaturated polyesters, acrylated polyethers, acrylated acrylics, and the like, or combinations of the above. The acrylated functional group can be mono-functional, di-functional, tri-functional, tetra-functional, penta-functional, or hexa-functional.
• As with the oligomers, a wide range of monomers can be used in the present compositions. Once again, it is only necessary that the overall composition be UV-curable and that the composition be capable of carrying the antimicrobial agents. For example, the monomers can be 2-ethyl hexyl acrylate, isooctyl acrylate, isobornylacrylate, 1,6-hexanediol diacrylate, diethylene glycol diacrylate, triethylene glycol diacrylate, pentaerythritol tetra acrylate, penta erythritol tri acrylate, dimethoxy phenyl acetophenone hexyl methyl acrylate, 1,6 hexanidiol methacrylate, and the like, or combinations of these compounds.
• In order to allow for UV-curing, the composition should be provided with an adequate and compatible photoinitiator. In certain embodiments of the invention, the photoinitiators can be: 1) single molecule cleavage type, such as benzoin ethers, acetophenones, benzoyl oximes, and acyl phosphine oxide, and 2) hydrogen abstraction type, such as Michler's ketone, thioxanthone, anthroguionone, benzophenone, methyl diethanol amine, 2-N-butoxyethyl-4-(dimethylamino) benzoate, and the like, or combinations of these materials.
• In certain embodiments, a rheological modifier can preferrably be added to the composition. The rheological modifier allows the flow characteristics of the composition to be controlled and modified as desired. The rheological modifier can also aid in the uniform distribution of antimicrobial agent and other materials within the composition. Suitable rheological modifiers may include organic clay, castor wax, polyamide wax, polyurethane, and fumed silica or combinations of these materials.
• Various antimicrobial agents may be used in the compositions of the present invention. It is only necessary that the antimicrobial agent be compatible with the other components of the compositions and that it be effective in controlling microbial agents. Specifically, it is preferred that that antimicrobial agent not chemically react with the other components of the composition. As discussed above, in certain embodiments it is preferred that the antimicrobial agent be capable of moving within the matrix of the composition such that it can be delivered to the site of the microbial agent. Examples of suitable antimicrobial agents within the scope of the present invention include be aldehydes, anilides, biguanides, silver element or its compounds, bis-phenols, and quaternary ammonium compounds and the like or combinations of the above.
• In another aspect, the invention may be solventless. As mentioned above, many conventional coatings employ harsh solvents such as THF and DMF. The present invention is operable without the use of solvents and, therefore, avoids the difficulties presented by the use of conventional solvents.
• The formulations also demonstrate good adhesion to numerous plastic surfaces (such as PC, PU, PVC, acrylics, and SBR). The formulation can be cured with adequate ultraviolet light (wavelength of approximately 200 nm to 600 nm, and in certain embodiments in the range of from about 300 nm to about 450 nm).
• Accordingly, the present invention provides antimicrobial coating compositions which overcome many of the limitations of existing technology. The present invention employs known components which have achieved acceptance for medical use. These components are combined and used easily and efficiently. As set forth above, the compositions of the present invention generally including oligomers, monomers, photoinitiators, rheological modifiers, and suitable antimicrobial agents. The resulting compositions are easily applied to the surfaces of medical devices and quickly cured by UV light.
DETAILED DESCRIPTION OF THE INVENTION
• This detailed description of the invention provides additional description of each of the aspects of the invention summarized above. In one aspect of the invention, an antimicrobial ultra violet (UV)-curable coating is provided. The coating comprising a UV curable composition comprising an oligomer, a monomer, and a photoinitiator which are together capable of forming a UV curable polymer composition. In certain embodiments, the composition may also include a rheology modifier in order to improve the flow characteristics of the composition and uniform distribution of components within the compositions. Finally, incorporated within the UV curable coating compositions is an effective antimicrobial agent.
• The UV curable coating compositions are comprised primarily of one or more oligomers and one or more monomers, combined with one or more suitable photoinitiators. In following discussing, the UV curable coating composition will comprise 100 parts by weight. Materials added to the UV curable coating composition may include rheological modifiers, antimicrobial agents, and other additives. These materials will be defined in parts by weight added to 100 parts by weight of the UV curable coating composition.
• The oligomer is generally selected from the group consisting of acrylated aliphatic urethanes, acrylated aromatic urethanes, acrylated polyesters, unsaturated polyesters, acrylated polyethers, acrylated acrylics, and the like, or combinations thereof. The acrylated functional group is selected from the group consisting of mono-functional, di-functional, tri-functional, tetra-functional, penta-functional, and hexa-functional acrylates. Any oligomer which is compatible with the other components of the composition is usable within the scope of the present invention. The oligomer will typically comprise from about 10% to about 90% of the UV curable composition. In some embodiments the oligomer will comprise from about 20% to about 80% of the UV curable composition. In certain embodiments of the invention the oligomer will comprise from about 30% to about 70% of the UV curable composition.
• The monomer is selected from the group consisting of 2-ethyl hexyl acrylate, isooctyl acrylate, isobornylacrylate, 1,6-hexanediol diacrylate, diethylene glycol diacrylate, triethylene glycol diacrylate, pentaerythritol tetra acrylate, penta erythritol tri acrylate, dimethoxy phenyl acetophenone hexyl methyl acrylate, 1,6 hexanidiol methacrylate and the like, or combinations of these compounds. Once again any monomer which is compatible with the other components of the composition is usable within the scope of the present invention. The monomer will typically comprise from about 5% to about 90% of the UV curable composition. In some embodiments the monomer will comprise from about 10% to about 75% of the UV curable composition. In certain embodiments of the invention the monomer will comprise from about 20% to about 60% of the UV curable composition.
• The photoinitiator is selected from the group consisting of single molecule cleavage type, such as benzoin ethers, acetophenones, benzoyl oximes, and acyl phosphine oxide, and hydrogen abstraction types consisting of Michler's ketone, thioxanthone, anthroguionone, benzophenone, methyl diethanol amine, and 2-N-butoxyethyl-4-(dimethylamino) benzoate. The photoinitiaor will also be selected such that it is compatible with the other components of the composition is usable within the scope of the present invention. The photoinitiator will typically comprise from about 0.5% to about 10% of the UV curable composition. In some embodiments the photoinitiator will comprise from about 1% to about 8.5% of the UV curable composition. In certain embodiments of the invention the photoinitiator will comprise from about 2% to about 7% of the UV curable composition.
• As mentioned above, certain additional components are added to the UV curable composition. Prominent among these are suitable rheological modifiers and antimicrobial agents. As mentioned above, the amounts of these additional components will be expressed in parts by weight added to 100 parts by weight of UV-curable composition.
• The rheological modifier is selected from the group consisting of organic clay, castor wax, polyamide wax, polyurethane, and fumed silica. The Theological modifier generally comprises from about 0.1 to about 30 parts by weight added to 100 parts by weight of UV curable composition, i.e. the UV curable composition is 100 weight units, while the rheological modifier comprises from about 0.1 to about 30 parts of additional weight. In other embodiments, the rheological modifier comprises from 0.1 to about 20 parts by weight compared to 100 parts by weight of the UV curable composition. In certain further embodiments, the Theological modifier comprises from about 0.2 to about 10 parts by weight compared to 100 parts by weight of the UV curable composition.
• The antimicrobial agent is generally selected from the group consisting of aldehydes, anilides, biguanides, silver, silver compound, bis-phenols, and quaternary ammonium compounds. The antimicrobial agent is generally present in the amount of from about 0.5 to about 50 parts by weight in compared to 100 parts by weight of the UV curable composition. In other embodiments, the antimicrobial agent may be present in the amount of from about 0.5 to about 30 parts by weight of the composition. In certain further embodiments, the antimicrobial agent is present in the amount of from about 0.5 to about 20 parts by weight.
• The antimicrobial agent may either dissolve in the UV curable composition or may be uniformly distributed therein. In this manner it is found that sufficient antimicrobial agent can migrate within the composition to contact the location of microbial activity. In any event, it is preferred that the antimicrobial agent not react chemically with the other components of the compositions.
• The UV coating formulations can be urethane or polyester type arylate such as 7104, 7101, 7124-K, 7105-5K from Electronic Materials Inc. (EMI) (EM Breckenridge, Co.), 1168-M, I-20781 from Dymax Corporation (Torrington, Conn.), UV 630 from Permabond Engineering Adhesives (Somerset, N.J.). The viscosity of the coating should be less than 10,000 cps, preferable below 5,000 cps, and most preferably between 20 to 1,000 cps.
EXAMPLESExample 1
• UV-curable compositions within the scope of the present invention were formulated and their microbial kill rate and zone of inhibition were tested as set forth in Table 1 below. Each of the compositions was essentially identical except for the antimicrobial agent which was varied as set forth below. The composition was comprised of a UV curable composition designated EMI 7104. The UV curable composition was comprised of 30-70% oligomer, 20-60% monomer; 2-7% photoinitiator. Added to 100 parts of the UV curable composition was 2.6 parts fumed silica obtained from Cabot and designated Cabot's MS-55. Also added was 7.2 parts antimicrobial agent. The specific antimicrobial agent was used in the formulation were as follows:
• • Samples #1. Chlorhexidine diacetate
    • 2. Alexidine
    • 3. Silver sulfadiazine
    • 4. Silver acetate
    • 5. Silver citrate hydrate
    • 6. Cetrimide
    • 7. Cetyl pyridium chloride
    • 8. Benzalknonium chloride
    • 9. o-phthalaldehyde
    • 10. Silver element
• Each composition was tested on three (3) microbial agents, namely:Staphylococcus epidermidis(gram positive bacteria),Pseudomonas aeruginosa(gram negative bacteria), andCandida albicans(yeast or fungi). The results are summarized in Table 1.

• TABLE 1
  The Contact Kill and Zone of Inhibition of UV Coating1
  Formulations

  Contact Kill (% Kill)

  Zone of

  S. epidermidis3

  P. aeruginosa

  C. albicans

  Inhibition (mm)

  Sample #2

  1 min

  1 hr

  8 hr

  1 min

  1 hr

  8 hr

  1 min

  1 hr

  8 hr

  S. epider

  P. aerug

  C. albican

  1	74.4	100	ND	90.6	100	ND	growth	100	ND	22.5	13.5	23.0
  2	79.3	100	ND	71.4	100	ND	growth	100	ND	13.5	0.0	13.5
  3	0.0	35.5	100	44.3	85.5	100	growth	growth	100	14.0	13.5	18.0
  4	4.6	32.2	100	20.0	29.8	100	growth	growth	growth	13.0	12.0	15.0
  5	11.5	31.4	100	37.1	36.2	100	growth	growth	100	7.0	6.5	9.0
  6	100	ND	ND	100	ND	ND	100	ND	ND	28.5	7.5	24.0
  7	100	ND	ND	100	ND	ND	100	ND	ND	18.0	0.0	15.0
  8	20.7	ND	100	100	ND	ND	growth	100	ND	21.5	0.0	22.5
  9	2.3	20.3	100	7.1	0.0	100	growth	growth	100	0.0	0.0	0.0
  10	1.2	44.1	100	24.3	46.8	100	growth	growth	growth	105	9.0	12.0
  ND - no data in view of 100% kill previously
  Growth - continued microbial growth

• Each of the compositions was generally effective in killing the bacterial agents. All of the compositions, except that containing silver element, were effective in killingCandida albicanswith one (1) hour. As set forth in Table 1 is appears that cetyl pyridium chloride and cetrimide were generally more effective than the other antimicrobial agents.
Example 2
• In these examples several antimicrobial agents were incorporated into UV curable coating compositions within the scope of the present invention. Each of the formulations included 100 parts of 7104 UV coating, 2.6 parts of fumed silica [designed M-5], and 5.0 parts of antimicrobial agent. Silver and chlorhexidine were included in the test because they are commonly used antimicrobial agents being used in medical technologies. The results of these tests are set forth in Table 2.

• TABLE 2
  Contact Kill and Zone of inhibition of selective
  antimicrobial agents in UV formulation (5% agents)

  Products

  Contact Kill (%)

  Zone of Inhibition

  1 Minute (5%)	S. Epi	P. Aeru	C. Albi	S. Epi	P. Aeru	C. Albi
  Chlorhexidine	37.6	0.0	39.0	21.5	13.5	19.0
  Diacetate
  Cetrimide	72.2	96.6	87.8	30.0	0.0	23.0
  Cetyl Pyridium	100.0	100.0	100.0	16.5	0.0	13.0
  Chloride
  Benzalkonium	15.8	0.0	58.5	23.5	0.0	23.5
  Chloride
  Silver*2	—	—	—	—	—	—
  Chlorhexidine	—	—	—	—	—	—
  Gluconate*2

• When 7 parts antimicrobial agent is used the results set forth in Table 3 were obtained.

• TABLE 3
  Contact Kill (%) and Zone of inhibition (mm) of selective antimicrobial
  agents in UV formulation (7% agents)

  Products

  Contact Kill (%)

  Zone of Inhibition

  1 Minute (7%)	S. Epi	P. Aeru	C. Albi	S. Epi	P. Aeru	C. Albi

  Chlorhexidine	24.6	37.7	26.3	21.8	11.5	17.3
  Diacetate
  Cetrimide	100	100	97.3	28.5	“+”	20.5
  Cetyl Pyridium	100	100	100	16.3	0.0	13.0
  Chloride
  Benzalkonium	100	100	72.9	24.8	0.0	23.5
  Chloride
  Silver	0.0	0.0	13.7	7.5	7.5	10.0
  Chlorhexidine	0.0	0.0	2.0	13.0	0.0	0.0
  Gluconate

Example 3
• In Table 4, the formulation set forth above was prepared using cetyl pyridium chloride (formulation #1) as the antimicrobial agent. This composition has 100% contact kill within 1 min. The same formulation using chlorhexidine diacetate (formulation #4) as the agent has 100% contact kill within 1 hour for all three types of microorganisms. However, both conventional compositions had 100% contact kill for selected microbes only after about 8 hours (both are using silver compound or silver element as the agent).

• TABLE 4
  Commercial Formulation Analysis

  Contact Kill (%)

  Zone of Inhibition (mm)

  Products	S. Epi	P. Aeru	C. Albi	S. Epi	P. Aeru	C. Albi

  Commercial Formulation 1

  1 min.	—	—	—	—	—	—
  1 hr.	0.0	9.2	11.0
  8 hr.	100	99.7	0.0

  Commercial Formulation 2

  1 min.	0.0	0.0	13.7	7.5	7.5	10.0
  1 hr.	0.0	100	95.2
  8 hr.	100	100	89.5

  (PC) 1

  1 min.	100	100	100	16.3	0.0	13.5
  1 hr.	100	100	100
  8 hr.	100	100	100

  (PC) 4

  1 min.	24.6	37.7	26.3	21.8	11.5	17.3
  1 hr.	100	100	100
  8 hr.	100	100	100
  (PC) 1: Cetyl pyridium chloride as the agent.
  (PC) 4: Chlorhexidine diacetate as the agent

Example 4
• Table 5 shows that the four agents identified above can have 100% contact kill within 1 hour and last up to almost 4 days when usingS. epidermidisas the microbe. However, conventional silver agent formulations have no 1 hour contact kill at all starting from day 1.

• TABLE 5
  Saline Leach Rate Tests for Selected Antimicrobial Agents (1 hr.
  contact kill by usingStaphylococcus epidermidisas the microbe)

  	0 Hr	24 Hrs	48 Hrs	72 Hrs	94 Hrs

  	1	100	100	100	100	100
  	2	100	100	100	100	100
  	3	100	100	100	100	100
  	4	100	100	100	100	100
  	5	0.0	1.96	0.0	0.0	0.0
  	6	100	76.5	55.4	87.8	100
  	* Note:
  	1. Cetyl pyridium chloride
  	2. Cetrimide
  	3. Benzalkonium chloride
  	4. Chlorhexidine diacetate
  	5. Silver
  	6. Chlorhexicine gluconate

Example 5
• Saline leach tests were conducted on the compositions described above. As set forth in Table 6 it was observed that chlorhexicine gluconate significantly loses its 1 hour contact kill ability after 48 hours when usingP. aeruginosaas the microbe. However, the other agents appear to retain contact kill ability for up to 94 hours.

• TABLE 6
  Saline Leach Rate Tests for Selected Antimicrobial Agents (1 hr.
  contact kill by usingPseudomonas aeruginosaas the microbe)

  	0 Hr	24 Hrs	48 Hrs	72 Hrs	94 Hrs

  	1	100	100	100	100	100
  	2	100	100	100	100	100
  	3	100	100	100	100	99.4
  	4	100	100	100	100	100
  	5	100	100	100	100	100
  	6	100	96.0	96.5	1.2	0.0
  	* Note:
  	1. Cetyl pyridium chloride
  	2. Cetrimide
  	3. Benzalkonium chloride
  	4. Chlorhexidine diacetate
  	5. Silver
  	6. Chlorhexicine gluconate

Example 6
• From the data in Table 7, it is clear that both conventional formulations (silver or chlorhexidine gluconate) significantly lose their efficacy after 24 hours when usingCandida albicansas the microbe. The top four agents tested herein have 100% efficacy for up to 94 hrs.

• TABLE 7
  Saline Leach Rate Tests for Selected Antimicrobial Agents (1 hr.
  contact kill by usingCandida albicansas the microbe)

  	0 Hr	24 Hrs	48 Hrs	72 Hrs	94 Hrs

  	1	100	100	100	100	100
  	2	100	100	100	100	100
  	3	100	100	100	100	100
  	4	100	100	100	100	100
  	5	95.2	97.6	62.4	30.0	39.7
  	6	87.6	100	29.1	25.4	12.7
  	* Note:
  	7. Cetyl pyridium chloride
  	8. Cetrimide
  	9. Benzalkonium chloride
  	10. Chlorhexidine diacetate
  	11. Silver
  	12. Chlorhexicine gluconate

Example 7
• In this example several formulations within the scope of the present invention were made. The UV-curable composition was varied using various proprietary formulations manufactured by EMI. Antimicrobial activity was measured and compared to elongation at break. The data is as follows:

• TABLE 8
  Elongation at Break

  	0 Hour	24 Hour	48 Hour	72 Hour	96 Hour

  S. epidermidis- 1 Hour

  	1	100	100	100	100	100
  	11	100	90.5	10.6	0	0
  	31	90.7	0	23.4	0	0
  	41	100	100	100	100	100
  	51	100	100	100	100	100

  P. aeruginosa- 1 Hour

  	1	100	100	99.8	100	100
  	11	100	100	0	0	0
  	31	100	100	0	0	0
  	41	100	100	98.8	100	100
  	51	100	0	0	0	0

  C. albicans- 1 Hour

  	1	100	100	91.7	89.7	97.1
  	11	100	59.6	22.2	0	0
  	31	50	24.5	8.33	0	0
  	41	100	100	97.9	95.5	99.6
  	51	100	73.9	12.5	0	0

Claims (23)

1. An antimicrobial ultraviolet (UV) curable coating comprising:

a UV curable composition comprising an oligomer, a momoner, and a photo initiator;

a rheology modifier; and

an antimicrobial agent.

2. The antimicrobial UV curable coating ofclaim 1 wherein the oligomer is selected from the group consisting of acrylated aliphatic urethanes, acrylated aromatic urethanes, acrylated polyesters, unsaturated polyesters, acrylated polyethers, and acrylated acrylics.

3. The antimicrobial UV curable coating ofclaim 2 wherein the acrylated functional group is selected from the group consisting of mono-functional, di-functional, tri-functional, tetra-functional, penta-functional, and hexa-functional acrylates.

4. The antimicrobial UV curable coating ofclaim 1 wherein the monomer is selected from the group consisting of 2-ethyl hexyl acrylate, isooctyl acrylate, isobornylacrylate, 1,6-hexanediol diacrylate, diethylene glycol diacrylate, triethylene glycol diacrylate, pentaerythritol tetra acrylate, penta erythritol tri acrylate, dimethoxy phenyl acetophenone hexyl methyl acrylate, and 1,6 hexanidiol methacrylate,

5. The antimicrobial UV curable coating ofclaim 1 wherein the photoinitiator is selected from the group consisting of benzoin ethers, acetophenones, benzoyl oximes, acyl phosphine oxide, and Michler's ketone, thioxanthone, anthroguionone, benzophenone, methyl diethanol amine, and 2-N-butoxyethyl-4-(dimethylamino)benzoate.

6. The antimicrobial UV curable coating ofclaim 1 wherein the rheological modifier is selected from the group consisting of organic clay, castor wax, polyamide wax, polyurethane, and fumed silica.

7. The antimicrobial UV curable coating ofclaim 1 wherein the Theological modifier is fumed silica.

8. The antimicrobial UV curable coating ofclaim 1 wherein the antimicrobial agent is selected from the group consisting of aldehydes, anilides, biguanides, silver, silver compound, bis-phenols, and quaternary ammonium compounds.

9. The antimicrobial UV coating ofclaim 1 wherein the antimicrobial agent is selected from the group consisting of cetrimide and cetyl pyridium chloride.

10. The antimicrobial UV coating ofclaim 1 wherein the antimicrobial agent is selected from the group consisting of chlorhexidine diacetate, alexidine, and benzalkonium chloride.

11. The antimicrobial UV curable coating ofclaim 1 wherein the composition comprises rheological modifier in the amount of from about 0.1 to about 30 parts by weight in 100 parts by weight the UV-curable composition.

12. The antimicrobial UV curable coating ofclaim 1 wherein the composition comprises Theological modifier in the amount of from about 0.2 to about 20 parts by weight in 100 parts by the weight of the UV-curable composition.

13. The antimicrobial UV curable coating ofclaim 1 wherein the composition comprises rheological modifier in the amount of from about 0.2 to about 10 parts by weight in 100 parts by weight of the UV-curable composition.

14. The antimicrobial UV curable coating ofclaim 1 wherein the composition comprises antimicrobial agent in the amount of from about 0.5 to about 50 parts by weight in 100 parts by weight of the UV-curable composition.

15. The antimicrobial UV curable coating ofclaim 1 wherein the composition comprises antimicrobial agent in the amount of from about 0.5 to about 30 parts by weight in 100 parts by weight of the UV-curable composition.

16. The antimicrobial UV curable coating ofclaim 1 wherein the composition comprises antimicrobial agent in the amount of from about 0.5 to about 20 parts by weight in 100 parts by weight of the UV-curable composition.

17. A UV curable coating composition comprising:

a) a UV curable composition, having;

from about 10% to about 90% by weight oligomer selected from the group consisting of acrylated aliphatic urethanes, acrylated aromatic urethanes, acrylated polyesters, unsaturated polyesters, acrylated polyethers, and acrylated acrylics;

from about 5% to about 90% by weight monomer selected from the group consisting of 2-ethyl hexyl acrylate, isooctyl acrylate, isobornylacrylate, 1,6-hexanediol diacrylate, diethylene glycol diacrylate, triethylene glycol diacrylate, pentaerythritol tetra acrylate, penta erythritol tri acrylate, dimethoxy phenyl acetophenone hexyl methyl acrylate, and 1,6 hexanidiol methacrylate;

b) from about 0.1 to about 30 parts by weight rheology modifier in 100 parts UV curable composition, the rheology modifier selected from the group consisting of organic clay, castor wax, polyamide wax, polyurethane, and fumed silica;

c) from about 0.5 to about 50 parts by weight antimicrobial agent in 100 parts UV curable composition, the antimicrobial agent selected from the group consisting of aldehydes, anilides, biguanides, silver, silver compound, bis-phenols, and quaternary ammonium compounds; and

d) from about 1 to about 10 parts photoinitiator.

18. An antimicrobial coating comprising:

a UV curable composition having an oligomer, a monomer, a photoinitiator, a rheology modifier; and

an antimicrobial agent selected from the group consisting of cetrimide, cetyl pyridium chloride, chlorhexidine diactetate, alexidine, and benzalkonium chloride.

19. The antimicrobial coating ofclaim 17 wherein the antimicrobial agent is alexidine.

20. The antimicrobial coating ofclaim 17 wherein the antimicrobial agent is cetrimide and cetyl pyridium chloride.

21. The antimicrobial coating ofclaim 17 wherein the antimicrobial agent is chlorhexidine diacetate.

22. The antimicrobial coating ofclaim 17 wherein the antimicrobial agent is benzalkonium chloride.

23. The antimicrobial coating ofclaim 17 further comprising a rheology modifier comprising fumed silica.