NON-CORROSIVE STERILANT COMPOSITION

Abstract: A non-corrosive, liquid, aqueous sterilant composition (as a concentrate or ready-to-use solution), which may be provided in two parts which are mixed prior to application, may comprise a peracid (in an equilibrium solution with an underlying carboxylic acid or mixtures of alkyl carboxylic acids and peroxide), inorganic buffering agent, and water. It has been found that the use of this simplified system, even in the absence of additional components which have been thought to be desirable for sterilants used on metal parts (e.g., copper and brass corrosion inhibitors, chelating agents, anti-corrosive agents) display excellent performance and that these additional components are not necessary, and that the presence of these additional materials at least complicates disposal of the spent solutions and could complicate compatibility of the sterilant solutions with some polymeric materials, especially where organic materials are used as the additional components, which organic materials may interact with, dissolve or solubilize in the polymeric materials.

Description: NON-COR OSTVE STERILANT COMPOSTTTON The present invention relates to compositions which can be used to safely and effectively disinfect surfaces and articles against microbiological forms. The compositions are easily handled, tend to be non-corrosive to the types of polymeric, elastomeric and metal surfaces found in medical instruments, are relatively shelf-stable, and may be prepared quickly and easily by simply blending component solutions. The importance of the sterilization of medical instruments and implants has been understood for more than two centuries. The need for sterilization has become even more important recently with the appearance of strains of microbiological forms which are resistant to conventional microbiocides such as antibiotics. It has become very important to sterilize medical devices to kill or remove the more resistant strains of microbiological forms before they infect a patient. Additionally, the sterilants must be generally effective against microorganisms covering a wide range of classes and species, with U.S. Government standards requiring efficacy against both bacteria and spores. Sterilization of medical devices has been performed for many years by immersing the medical devices in an atmosphere which is antagonistic to the survival of the microbiological forms. Among the environments which have been used to attempt to sterilize medical instruments include, but is not limited to, steam, alcohols, ethylene oxide, formaldehyde, gluteraldehyde, hydrogen peroxide, and peracids. Each of these materials has its benefits and limitations. Ethylene oxide tends to be very effective against a wide range of microorganisms, but it is highly flammable and is generally used in a gas phase which may require more stringent environmental restraints than would a liquid. Alcohols are similarly flammable and must be used in very high concentrations. Steam has a more limited utility, having to be used in a controlled and enclosed environment, requiring the use of large amounts of energy to vaporize the water, and requiring prolonged exposure periods to assure extended high temperature contact of the steam with the organisms. Hydrogen peroxide has limited applicability because it is unstable and not as strong as some other sterilants. The peracids have become more favorably looked upon, but they tend to be corrosive (being an oxidizing acid) and are not shelf stable. U.S. Patent No. 5,508,046 describes a stable, anticorrosive peracetic acid/peroxide sterilant comprising a concentrate including peracetic acid, acetic acid, hydrogen peroxide (in a ratio of 1 : 1 to 11 :1 total acid/hydroxide), and 0.001 to 200 parts per million of stabilizers such as phosphonic acids and sodium pyrophosphates. The concentrates are diluted about 20 to 40 times so that the maximum concentration of stabilizer in the use solution would be about 10 parts per million. The stabilizers are described as acting as chelating agents by removing trace metals which accelerate the decomposition of the peroxides. U.S. Patent No. 5,616,616 describes a room temperature sterilant particularly useful with hard tap water comprising an ester of formic acid, an oxidizer (such as hydrogen peroxide or urea hydrogen peroxide), performic acid and water. The use of corrosion inhibitors (such as benzotriazoles, azimidobenzene, and benzene amide) and stabilizers (unnamed) is also generally suggested. U.S. Patent No. 5,077,008 describes a method of removing microbial contamination and a solution for use with that method. The solution comprises a combination of five ingredients in water: 1) a strong oxidant (including, for example, organic peroxides, peracids, an chloride releasing compounds, with peracetic acid in a concentration of 0.005 to 1.0% being preferred), 2) a copper and brass corrosion inhibitor (e.g., triazoles, azoles and benzoates), 3) a buffering agent (including, for example, phosphate), 4) at least one anti-corrosive agent which inhibits corrosion in at least aluminum, carbon steel and stainless steel selected from the group consisting of chromates and dichromates,, borates, phosphates, molybdates, vanadates and tungstates, and 5) a wetting agent. A sequestering agent may be used to prevent the phosphates from causing precipitation in hard water. U.S. Patent Nos. 4,892,706 and 4,731,22 describe automated liquid sterilization systems having a plurality of modules which store the sterilant solution and the rinse solution. U.S. Patent No. 5.037,623 describes a sterilant concentrate injection system which is a spill resistant, vented ampule system for use with sterilization systems. Medical devices now include many polymeric components for reasons of material costs and ease of manufacture. Many of the systems and solutions designed for the sterilization of metal medical devices are not necessarily suitable for use with polymeric components, and may cause corrosion of the polymeric materials. It is therefore necessary to formulate sterilization compositions which are compatible with both metal and polymeric components of the medical devices. It is also always desirable to provide sterilization systems with fewer components in the composition, where the sterilization solutions do not significantly sacrifice microbiocidal activity and do not corrode the materials used in medical devices. SUMMARY OF THE TNVENTTON A non-corrosive, liquid, aqueous sterilant composition (as a concentrate or ready-to-use solution), which may be provided in two parts which are mixed prior to application, may comprise a peracid (in an equilibrium solution with an underlying carboxylic acid or mixtures of alkyl carboxylic acids and peroxide), inorganic buffering agent, and water. It has been found that the use of this simplified system provides excellent sterilization ability, even in the absence of additional components which have been thought to be desirable for sterilants used on metal parts (e.g., copper and brass corrosion inhibitors, chelating agents, anti-corrosive agents) which have been found to not be necessary. The presence of these additional materials at least complicates disposal of the spent solutions and could complicate compatibility of the sterilant solutions with some polymeric materials, especially where organic materials are used as the additional components, which organic materials may interact with, dissolve or solubilize in the polymeric materials. The concentration of the components has shown itself to be important in providing non-corrosive effects towards a wide variety of structural materials in medical devices and yet providing effective sterilization effects against spores and bacteria, including tuberculosis bacteria in an acceptable amount of time. An aqueous sterilant use solution according to the present invention may comprise a solution having a pH of from 5.0 to 7.0 comprising from 100 to 10,000 parts per million of a peroxy acid and 30 to 5000 parts per million of buffering agent, preferably without any organic anticorrosive agents. The aqueous sterilant solution may, for example, comprise from 100 to 10,000 parts per million of a peroxy acid, 30 to 5000 parts per million of buffering agent and a catalytically effective amount of a catalyst for peroxygenation of a carboxylic acid by hydrogen peroxide. The aqueous sterilant solution may consist essentially of a solution having a pH of from 5.0 to 7.0 comprising from 100 to 10,000 parts per million of a peroxy acid, 30 to 5000 parts per million of buffering agent and a catalytically effective amount of a catalyst for peroxygenation of a carboxylic acid by hydrogen peroxide. The method may particularly comprise mixing a first and a second solution to form a sterilizing solution comprising a peroxy acid, said first solution comprising a carboxylic acid, hydrogen peroxide and water, and said second solution comprising a buffering agent for pH between about 5 and 7, said sterilizing solution comprising at least 100 parts per million of peroxy acid at a pH of 5 to 7, immersing said article in said sterilizing solution for at least 5 minutes to sterilize said article, said first solution and second solution being free of organic anti-corrosion agents for brass and/or copper, and said article comprising a medical article having parts made of at least two materials selected from the group consisting of metals, polymers and rubbers. PET ATI. ED DESCRTPTTON OF THE TNVENTTON The aqueous sterilant compositions of the present invention comprise a peracid, water-soluble peroxide source, and carboxylic acid in a buffered solution at pH levels between about 5.0 and 7.0. The use of an inorganic buffering agent also enables the use of slightly water-soluble, higher molecular weight carboxylic acids in the formation of peroxy acids with the peroxide source thereby reducing the amount of deposits from fatty acid residue in the solution. Phosphate buffers are effective dispersants and suspending agents for these fatty acid residues. The peroxy acid useful in the practice of the present invention may comprise any organic peroxy acid. These acids are well known in the art to be formed from any carboxylic acid containing compound. Normally they are prepared from carboxylic acids of the formula: CH 3 -(CH 2 )n-COOH wherein n is 0 to 18, preferably 0 to 12 and more preferably 0 to 10, with the corresponding peroxy acid having the formula: CH 3 -(CH 2 )n-CO 3 H wherein n is as defined above. The alkyl moiety on the acid, CH 3 -(CH 2 )n- may be replaced with hydrogen or any, preferably low molecular weight, organic group so that the acid and the resulting peroxy acid may be represented by: R- CO 2 H and R-CO 3 H, respectively. The molecular weight of R could be 1, but preferably should be between 15 and 155. Carboxylic acids which are generally useful in the invenetion are those which comprise percarboxylic acids. Percarboxylic acids generally have the formula R(Co 3 H n ), where R is an alkyl, arylaklyl, cycloalkyl, aromatic or heterocyclic group, and N is 1 , 2, or 3 and named by prefixing the parent acid with peroxy. The peracid normally exists in an equilibrium state with the original or fundamental acid and the peroxide source, usually hydrogen peroxide. Typical peracids include peracids of C, to C ]2 carboxylic acids such as formic acid, acetic acid, propanoic acid, butanoic acid, pentanoic acid, hexanoic acid, heptanoic acid, octanoic acid, nonanoic acid, decanoic acid, undecanoic acid, dodecanoic acid, and the like. The term carboxylic acids as used in the practice of the present invention, unless otherwise limited, also includes mono- and di- hydroxycarboxylic acids such as glycolic acid, lactic acid and citric acid. An example of di-hydroxycarboxylic acid or di-hydroxy is tartaric acid, and also fumaric acid, which is an unsaturated di-hydroxycarboxylic acid. Diacids such as alpha-omega-dicarboxylicpropanoic acid, succinic acid, glutaric acid, adipic acid, and the like may also be used to form di-peracids. Peroxycarboxylic acids may also be present and included within the solutions of the present invention. Mixtures and combinations of the peracids may also be used in the systems of the invention, as well as other addenda as generally described herein. The peroxide source is preferably an aqueous solution of hydrogen peroxide, but may also include such alternative peroxide sources as solutions of sodium peroxide, calcium peroxide, alkali salts of percarbonate and persulfate, and even organic peroxides such as dicumyl peroxide, dialkyl peroxides, urea peroxide, and the like, forming the basis of the solution of the hydrogen peroxide. The inorganic peroxides are preferred as the source of the solution of the hydrogen peroxide. The ratio of the peroxy acid to the hydrogen peroxide can also significantly influence the efficacy of the solutions of the invention, with higher ratios of the peroxy acid to the hydrogen peroxide preferred. For example, its is more desirable to have a ratio of at least 2:1 or 3 : 1 (peroxy acid to hydrogen peroxide), and more desirable to have higher ratios of at least 4:1, at least 5:1 or at least 8:1 or more (peroxy acid to hydrogen peroxide). The buffering agent is a compound, again preferably an inorganic compound which will maintain a buffered pH level in the solution of the composition between 5.0 and 7.0. Buffering agents include, but are not limited to phosphates, borates, lactates, acetates, citrates, vanadates, tungstates, and combinations thereof, particularly alkali metal or alkaline metal salts of these agents. The use of phosphates exclusively or at least primarily (e.g., at least 50%, at least 65%, at least 75%, or at least 90 or 95% by weight of the buffering agents) is particularly useful. Trisodium phosphate has been found to be particularly desirable because of its ability to maintain the acid residues of the peroxy acids in solution where they will not form film in the solution which can be picked up by any sterilization apparatus or medical device which is being sterilized. It is interesting to note that phosphates have been generally taught to be avoided in sterilization solutions where hard water may be contacted because of the potential for calcium precipitation, yet in the present invention, the presence of phosphates reduces the formation of organic residue film on the surface of the solution. The buffering agent alone, even when a phosphate or especially when a phosphate and particularly trisodium phosphate, has been found to reduce corrosion by the solution on all surfaces. The use of phosphate(s) alone, in the absence of copper and brass corrosion inhibitors has been found to be an effective sterilant, and provide non-corrosive activity against a wide range of structural materials, including, but not limited to rubbers, plastics and metals, such as stainless steel, aluminum, polypropylene, teflon, acrylonitrile/styrene/butadiene, polyolefins, vinyl resins (e.g., polyvinyl chloride, polyvinylbutyral), silicone resins and rubbers, and polyurethanes, and provide second tier protection for brass and copper. Although the peracids work more efficiently in their microbiocidal activity at highly acidic pH levels (below 4.0), those acidic levels are much more corrosive. The use of a buffering system which maintains the pH above 5.0 and preferably between about 5.0 and 7.0 still provides a microbiocidal activity at levels which meet all international standards, using anywhere from 150 to 10,000 parts per million peracid. The sterilant can be used as a manual system or be used in an automated system. The sterilant can be provided as a one-part or preferably two part concentrate, with the peracid in one solution and the buffer in the second solution. For example, in a two-part system, a peracid concentrate may be formed having .01% to 1% by weight peracid (e.g., peracetic acid), .003% to 1% by weight ppm hydrogen peroxide, .01% to 1% by weight acid (e.g., acetic acid), and the buffer solution may comprise, for example, from 0.5 to 75,000 ppm buffering agent (e.g., anhydrous trisodium phosphate) in water. Mixtures of these types of addenda, including the buffering agents and peracids, are clearly useful in the practice of the present invention. It is preferred that the concentrates have active ingredient contents at the higher levels of these ranges such as .1% to 15% by weight peracid, 5% to 80% by weight peroxide, 5% to 80% by weight acid and .1% to 15% by weight buffering agents. The diluted to use solution would preferably contain sufficient actives to provide .01% to 1.0% by weight peracid at a pH between about 5.0 and 7.0. The use solution need not contain any effective amount of many of the additives which prior art systems have required for non-corrosive effects (such as the organic anti-corrosive agents such as the triazines, benzotriazoles, azoles and benzoates), and yet provide a wider disclosed range of non-corrosivity against the many available surfaces of medical devices. The use solutions of the present invention may comprise a simplest solution comprising peracid (along with the acid and peroxide in equilibrium), buffering agent in an amount to provide a pH of from about 5.0 to 7.0, and water (preferably deionized water). This solution may be modified by the addition of individual agents such as chelating agents, surfactants (also referred to in the literature for sterilant compositions as wetting agents), and anti- corrosion agents. A typical concentrate solution which may be diluted to a use solution might comprise, 0.1% to 15% by weight peracid, 0.1% to 15% by weight buffering agent, with the remainder as water and other addenda as generally described herein (e.g., from 99.6 to 78% by weight water). These and other aspects of the invention will be further described by reference to the following, non-limiting examples. These data show that a preferred range for the concentration of peroxide in the solution (particularly as evidenced by hydrogen peroxide) less than 150 ppm, preferably less than 100 up to 80,000 ppm, still more preferably less than 100, less than 75 and less than 50 ppm. In the examples, POAA represents peroxyacetic acid, AA represents acetic acid, POOA represents peroxyoctanoic acid, and Oct. Acid represents octanoic acid. Dequest™ are commercially available materials which may be used in the solutions of the present invention. Dequest™ 2000 comprises aminotri(methylene-phosphonic acid), Dequest™ 2010 comprises 1 -hydroxy ethylidene-l,l-diphosphonic acid, and Dequest™ 2006 comprises aminotri(methylene-phosphonic acid) pentasodium salt. Dequest acts as a chelator for heavy metals. The data also shows that sporicidal activity of compositions with higher molecular weight peracids increase with higher proportions of the peracid as compared to the acid. The presence of a catalyst for the formation of the peracid in the sterilization compositions of the present invention also is a novel aspect of the present invention which could act to maintain the level of peracid in the solution during use. Corrosion Example I Experimental In the following comparison example, a formulation according to the present invention comprising 2.69 weight percent of a 13% solution of peracetic acid made by combining 78% glacial acetic acid, 21 % hydrogen peroxide (35% by weight in water), and 1% hydroxyethylenediamine phosphonate was compared to a commercial sterilization formulation (CSF) comprising a mixture of sodium perborate and tetraacetyl ethylenediamine with a buffer to provide a use solution of pH 8, with its necessary sterilization activator. The CSF composition (referred to as Powder PAA) comprises a powder source of peracetic acid (with a solid peroxide source) without a buffering agent, and was compared to a liquid solution of peracetic acid (PAA) made according to the present invention (referred to as Liquid PAA) by admixture of acetic acid and hydrogen peroxide solution with 1 % by weight of hydroxyethylenediamine phosphonate catalyst to form the solution of peracetic acid (with the equilibrium amounts of acetic acid and hydrogen peroxide) at a pH of 6.0 provided by 3.0% by weight trisodium phosphate. This commercial CSF product requires mixing of a dry powder, with a delay required for the activator TAED (tetra acetyl ethylene diamine) by reaction with sodium perborate to generate peracetic acid and microbiocidal activity in the components. Test Parameters; The test was performed on pieces of an Olympus flexible endoscopes using a washer/disinfector to reduce manual variables. The test parameters were room temperature conditions, with the following immersion times: Sample Cycles Immersion Time Liquid PAA 1 10 minutes Powder PAA 1 15 minutes Sample Application Time Liquid PAA 24 hours Powder PAA 8 hours The test was performed by completely immersing separate test pieces S 1 to S7 and Wl to W28 in each of the solutions. Test Pieces Item Earls S1 - S7 Parts of endoscope S8 and S9 Insertion tube S10 Light guide tube Wl - W28 Parats of washer/disinfector Conclusion The samples were carefully inspected to evaluate the cosmetic effects (corrosion effects) on the various pieces. The first examination (Item 1) was for parts of the endoscope. The second examination (Item 2) was for the insertion tube. The third examination (Item 3) was for the light guide tube. The fourth examination (Item 4) was for the washer/disinfector. The samples performed substantially identically, with both solutions showing only a slight cosmetic change in painted black surface of the endoscope (S3 surface). No functional or cosmetic changes were noted on any other sample. The simplicity of use for the Liquid PAA system was very noteworthy, with no delay in mixing or reaction time. The solutions could be directly added into an automated system while the CSF Powder PAA system would have required premixing and activation time before it could have been used in an automatic system. Corrosion Example TT Experimental A corrosion study was performed to evaluate peracid containing formulas with and without buffer addition upon selected metals, plastics and rubbers. Testing was conducted with two peracid formuations of 500 ppm (parts per million) peracetic acid (A) and 5000 ppm peracetic acid (B) concentration without buffer; and, two identical formulas (C and D respectively) with exception of buffer addition admixture. Coupons were completely immersed in 200 mis of defined test solution contained in covered 8 ounce glass jars maintained at 50°C within an environmental chamber. Solutions were changed daily. Study was conducted over a 14 day time period. For each test material, a control was also run which is a coupon of stated material placed within a covered 8 ounce glass jar having no test solution. Coupons were pretreated before the corrosion study began, and postreated before final comparitive measurements and visual observations were performed. Metal coupons were precleaned according to ASTM Vol. 3.02, G31- 72 and 3.02, Gl-90 protocol and post-treated accordingly prior to final measurement. Test conditions were modified from the ASTM protocol as explained in above paragraph. Plastic and rubber coupons were only rinsed with deionized water and air dried prior to corrosion study; and, similarly treated prior to final measurement and visual observation. Conclusion Addition of buffer admixture to peracetic acid composition test solutions significantly improves metals protection. The effect is less noticeable on test plastics; but, protection is provided selected test rubbers. PART IA: FORMULA - PERACID COMPONENT HIGH POAA - LOW H202 PERACID FORMULA KX-6091 GM ITEM RAW MATERIAL wτ% 10000 10 Acetic Acid 78.00 7800.00 20 Hydrogen Peroxide 21.00 2100.00 35% 30 Dequest T 1 M 1 2010 (60%) 1.00 100.00 Total 100.00 10000.00 Mixing Instructions: Batch was prepared by direct weighing on Mettler PM 16 Top Loading Balance into a 5 gal HMW/HDPE (high molecular weight/high density polypropylene) pail. The batch was mixed for 65 minutes using a lab mixer equipped with a plastic coated stir rod and blade. PART IB: FORMULA - ADMIXTURE OF I A AND BUFFER COMPONENT FORMULAS A, B, C, D CORROSION STUDY USE DILUTIONS (A) (B) (C) (D) ITEM Material wτ% GM/ GM/ WT% GMZ W.T% GM/ 4500 4500 _L_M 4500 10 Deionized 9910556 445975 9066311 407984 9955756 448009 955751 430088 Water 20 Trisodium 045200 2041 491200 22104 Phosphate Anhyd Gran 30 KX-6091 044244 1991 442489 19912 044244 1991 442489 19912 (1 1 3% POAA) Total 10000000 450007 10000000 450000 10000000 450000 10000000 450000 THEORETICAL ppm pH ppm pH ppm PH ppm PH VALUES POAA 500 6 00 5000 6 00 500 3 00 5000 2 50 INSTRUCTIONS Add Trisodium Phosphate Anhydrous Granules (item 20) by wt. to weighed amount of DI water and stir with Lab mixer until dissolved. Add (item 30) by wt. to buffered water and final mix 2 min. RESULTS: (A) - pH = 6.02 (B) - pH = 5.99 (C) - pH = 2.96 (D) - pH = 2.35 PART II: CORROSION - METALS 14 day Compatibility Test of 15 different materials tested against four different Test Solutions at 50°C with the test solutions are changed daily. Test item Test Solution Material Initial Wt. Final Wt. METALS i (gms) (gms) TWL CWL AWL mpy 1 (A) 500 ppm POAA/Buffered 316 SS 23.5792 23.5791 0.0001 0.0001 0.0000 0.0000 5 (B) 5000 ppm POAA/Buffered 316 SS 23.5194 23.5193 0.0001 0.0001 0.0000 0.0000 9 (C) 500 ppm POAA only 316 SS 23.5764 23.5762 0.0002 0.0001 0.0001 0.0031 13 (D) 5000 ppm POAA only 316 SS 23.5690 23.5689 0.0001 0.0001 0.0000 0.0000 17 CONTROL 316 SS 23.5846 23.5845 0.0001 0.0001 2 (A) 500 ppm POAA/Buffered 304 SS 17.9651 17.9650 0.0001 0.0000 0.0001 0.0031 6 (B) 5000 ppm POAA/Buffered 304 SS 17.9326 17.9323 0.0003 0.0000 0.0030 0.0938 10 (C) 500 ppm POAA only 304 SS 17.9795 17.9793 0.0002 0.0000 0.0002 0.0063 14 (D) 5000 ppm POAA only 304 SS 17.9993 17.9992 0.0001 0.0000 0.0001 0.0031 18 CONTROL 304 SS 18.1102 18.1102 0.0000 0.0000 3 (A) 500 ppm POAA/Buffered 7075 Aluminum 12.8716 12.8685 0.0031 0.0002 0.0029 0.2412 7 (B) 5000 ppm POAA/Buffered 7075 Aluminum 12.7575 12.7336 0.0239 0.0002 0.0237 1.9712 11 (C) 500 ppm POAA only 7075 Aluminum 12.8651 12.8392 0.0259 0.0002 0.0257 2.1376 15 (D) 5000 ppm POAA only 7075 Aluminum 12.8718 12.7439 0.1279 0.0002 0.1277 10.6213 19 CONTROL 7075 Aluminum 12.4899 12.4897 0.0002 0.0002 4 (A) 500 ppm POAA/Buffered 260 Brass 26.4108 26.3763 0.0345 0.0004 0.0341 0.9779 8 (B) 5000 ppm POAA/Buffered 260 Brass 26.4211 26.3307 0.0904 0.0004 0.0900 2.5809 12 (C) 500 ppm POAA only 260 Brass 26.6471 25.6695 0.9776 0.0004 0.9772 28.0233 16 (D) 5000 ppm POAA only 260 Brass 26.4949 18.9759 7.5190 0.0004 7.5186 215.6118 20 CONTROL 260 Brass 26.4352 26.4348 0.0004 0.0004 PART II: CORROSION - METALS - OBSERVATIONS Test Test Solution Material item METALS Visual Observations 1 (A) 500 ppm POAA/Buffered 316 SS Smooth, shiny silver colored material like control 5 (B) 5000 ppm POAA/Buffered 316 SS Smooth, shiny silver colored material like control 9 (C) 500 ppm POAA only 316 SS Smooth, shiny silver colored material like control 13 (D) 5000 ppm POAA only 316 SS Smooth, shiny silver colored material like control 17 CONTROL 316 SS Smooth, shiny silver colored material 2 (A) 500 ppm POAA/Buffered 304 SS Smooth, shiny silver colored material like control 6 (B) 5000 ppm POAA Buffered 304 SS Smooth, shiny silver colored material like control 10 (C) 500 ppm POAA only 304 SS Smooth, shiny silver colored material like control 14 (D) 5000 ppm POAA only 304 SS Smooth, shiny silver colored material like control 18 CONTROL 304 SS Smooth, shiny silver colored material 3 (A) 500 ppm POAA/Buffered 7075 Aluminum A sit. duller, sit. whiter than control, silver material 7 (B) 5000 ppm POAA/Buffered 7075 Aluminum A very dull, smokey brown colored material 11 (C) 500 ppm POAA only 7075 Aluminum A dull, whitish gray colored material 15 (D) 5000 ppm POAA only 7075 Aluminum A very dull, very whitish gray colored material 19 CONTROL 7075 Aluminum A sit. dull, silver colored material 4 (A) 500 ppm POAA/Buffered 260 Brass A mixture of dull gold & pink area colored material 8 (B) 5000 ppm POAA/Buffered 260 Brass A dull, gold colored material with patches of pink 12 (C) 500 ppm POAA only 260 Brass A darker dull gold colored material with pink areas 16 (D) 5000 ppm POAA only 260 Brass A sparkling grainy gold colored material 20 CONTROL 260 Brass A smooth, shiny, gold colored material KX-6091 CORROSION STUDY CALCULATION DATA 4 Metals DENSITY AREA in inches squared 316 Stainless Steel 7.98 6.5 304 Stainless Steel; 7.94 6.4 7075 Aluminum 2.81 6.8 260 Brass 8.5 6.52 Time & Temp Tested 14 days at 50°C mpy = (534,000 * AWL) / (A * T * D) (A) = Area (see above) (T) = Time (336 hrs) (D) = Density (see above) AWL = TWL - CWL TWL = Pre-testing weight - Post-testing weight CWL = Pre-testing weight of control - Post-testing weight of control mpy = mils per year PART III: CORROSION - PLASTICS Analytical - Observations KX-6091 CORROSION STUDY 14 day Compatibility Test of 15 different materials tested against four different Test Solutions at 50°C with the test solutions are changed daily. lest Test Solution Material Initial Wt. Initial Ht, Initial Initial Final Wt, % Weight Final Ht, % Height Final % final % Thick item PLASTICS (gms) (inches) Width Thick (gms) Change (inches) Change Width Width Thick Changes (Inches) (inches) (inches) Change (inches) 21 (A) 500 ppm Polyurethane 3 8348 2 996 0 506 0 128 3 8360 0 0313 2 996 0 0000 0 507 0 1976 0 128 0 0000 POAA/Buffered 27 (B) 5000 ppm Polyurethane 3 8379 2 996 0 502 0 129 3 8385 0 0156 2 998 0 0668 0 502 0 0000 0 128 -0 7752 POAA/Buffered 33 (C) 500 ppm POAA Polyurethane 3 8385 2 999 0505 0 128 3 8418 00860 3 004 0 1567 0 505 -0 1976 0 127 -0 7813 only 39 (D) 5000 ppm Polyurethane 3 8151 2 995 0 504 0 127 3 741 1 -1 9397 3 061 2 2037 0 509 0 9921 0 125 -1 5748 POAA only 45 CONTROL Polyurethane 3 8286 2 996 0505 0 128 3 8200 -02248 2 993 -0 1001 0504 -0 1980 0 128 0 0000 22 (A) 500 ppm Polyethylene 1 3741 2 991 0 505 0 066 1 3736 -0 0364 2 991 0 0000 0 504 -0 1980 0 066 0 0000 POAA/Buffered 28 (B) 5000 ppm Polyethylene 1 3676 2 991 0 505 0 064 1 3675 -0 0073 2 991 0 0000 0 505 0 0000 0 065 1 5625 POAA Buffered 34 (C) 500 ppm POAA Polyethylene 1 3541 2 992 0 504 0 065 1 3541 0 0000 2 991 -0 0334 0 502 -0 3968 0 065 0 0000 only 40 (D) 5000 ppm Polyethylene 1 3586 2 995 0 504 0 066 1 3593 0 0515 2 994 -0 0334 0 502 -0 3968 0 066 0 0000 POAA only 46 CONTROL Polyethylene 1 3668 2 991 0 504 0 068 1 3667 -0 0073 2 989 -0 0669 0 504 0 0000 0 068 0 0000 23 (A) 500 ppm Polypropylene 1 3792 3 002 0 504 0 066 1 3792 0 0000 3 001 -0 0333 0 503 -0 1984 0 067 1 5152 POAA/Buffered 29 (B) 5000 ppm Polypropylene 1 3774 2 998 0 503 0 065 1 3775 0 0073 2 999 0 0334 0 503 0 0000 0 066 1 5385 POAA/Buffered 35 (C) 500 ppm POAA Polypropylene 1 3793 2 998 0 504 0 065 1 3796 0 0218 2 998 0 0000 0 503 -0 1984 0 065 0 0000 only lest Test Solution Matenal Initial Wt. Initial Ht. Initial Initial Final Wt. % Weight Final Ht. % HeightFinal 00000 0065 00000 item PLASTICS (gms) Cinches) Width Thick (gms) Change Cinches) Change Width Cinches) Cinches. (inches) 47 CONTROL Polypropylene 1 3812 2 997 0 503 0 065 13811 -00072 2997 00000 0503 00000 0065 00000 24 (A) 500 ppm Polyvinyl 2 1801 3 002 0 505 0 066 21843 01927 3002 00000 0506 01980 0065 -15152 POAA/Buffered Chloride 30 (B) 5000 ppm Polyvinyl 2 2005 2 997 0 505 0 066 22041 01636 2997 00000 0506 01980 0066 00000 POAA/Buffered Chloride 36 (C) 500 ppm POAA Polyvinyl 2 1734 2 998 0 505 0 065 21777 01978 2998 00000 0505 00000 0065 00000 only Chloπde 42 (D) 5000 ppm Polyvinyl 2 1590 2 998 0 505 0 065 21625 01621 2997 -00334 0505 00000 0065 00000 POAA only Chloπde 48 CONTROL Polyvinyl 2 2048 2 999 0 505 0 056 22037 -00499 2998 -00333 0505 00000 0056 00000 Chloride 25 (A) 500 ppm ABS 1 4724 2 995 0 507 0 061 14762 02581 2999 01336 0508 01972 0061 00000 POAA/Buffered 31 (B) 5000 ppm ABS 1 5167 3 003 0 507 0 063 15201 02242 3006 00999 0506 -019720063 00000 POAA Buffered 37 (C) 500 ppm POAA ABS 1 5082 3 000 0 507 0 062 15132 03315 3004 01333 0508 01972 0062 00000 only 43 (D) 5000 ppm ABS 1 4971 2 995 0 505 0062 15047 05076 3000 01669 0510 09901 0062 00000 " POAA only 49 CONTROL ABS 1 4822 2 995 0 507 0 062 14813 -00607 2995 00000 0508 01972 0062 00000 26 (A) 500 ppm Polyacetal 44596 3 003 0 507 0 133 45033 09799 3010 02331 0508 01972 0134 07519 POAA/Buffered 32 (B) 5000 ppm Polyacetal 4 3970 3 003 0 507 0 131 44302 07551 3009 01998 0507 00000 0132 07634 POAA/Buffered 38 (C) 500 ppm POAA L Polyacetal 44967 3 004 0 506 0 134 45441 10092 3014 03329 0508 03953 0135 07463 only 44 (D) 5000 ppm Polyacetal 4 3832 3 003 0 507 0 131 44264 09856 3012 02997 0508 01972 0132 07634 POAA only 50 CONTROL Polyacetal 4 4498 3 002 0 506 0 133 44454 -00989 3000 -00666 0506 00000 0133 00000 Test Test Solution Material item PLASTICS Visual Observations 21 (A) 500 ppm POAA/Buffered Polyurethane Dull opaque orange material with semi-transparent boarder 27 (B) 5000 ppm POAA/Buffered Polyurethane Dull opaque orange material with semi-transparent boarder and sit. tacky 33 (C) 500 ppm POAA only Polyurethane Dull darker opaque orange material with semi-transparent boarder and sit. tacky 39 (D) 5000 ppm POAA only Polyurethane Very dark orange, very tacky, completely opaque material that stuck to drying surface resulting in loss of material 45 CONTROL Polyurethane A dull, dirty, sit. yellow tinted, semi-transparent material 22 (A) 500 ppm POAA/Buffered Polyethylene Sit. whiter material than control 28 (B) 5000 ppm POAA/Buffered Polyethylene Sit. whiter material than control 34 (C) 500 ppm POAA only Polyethylene Sit. whiter material than control 40 (D) 5000 ppm POAA only Polyethylene Sit. whiter material than control 46 CONTROL Polyethylene A dull, grayish white material 23 (A) 500 ppm POAA/Buffered Polypropylene A white filmy, faintly transparent, more cloudy material than control 29 (B) 5000 ppm POAA/Buffered Polypropylene A white filmy, faintly transparent, more cloudy material than control 35 (C) 500 ppm POAA only Polypropylene A white heavy filmed, faintly transparent, more cloudy material than control 41 (D) 5000 ppm POAA only Polypropylene A white filmy, faintly transparent, more cloudy material than control 47 CONTROL Polypropylene A dull gray, semi-transparent material 24 (A) 500 ppm POAA/Buffered Polyvinyl Sit. less shiny and sit. less dark gray material than control Chloride lest Test Solution Material item PLASTICS Visual Observations 36 (C) 500 ppm POAA only Polyvinyl A dull med. gray material Chloride 42 (D) 5000 ppm POAA only Polyvinyl A dull light to medium gray material Chloride 48 CONTROL Polyvinyl A dark, shiny gray material Chloride 25 (A) 500 ppm POAA/Buffered ABS A sit. dull, whiter material than control 31 (B) 5000 ppm POAA/Buffered ABS A sit. dull, whiter material than control 37 (C) 500 ppm POAA only ABS A sit. dull, much whiter white material than control 43 (D) 5000 ppm POAA only ABS A sit. dull bright white material 49 CONTROL ABS A sit. dull, vanilla white material t 26 (A) 500 ppm POAA Buffered Polyacetal A dull, cleaner white appearance than control 32 (B) 5000 ppm POAA/Buffered Polyacetal A dull, cleaner white appearance than control 38 (C) 500 ppm POAA only Polyacetal A dull, cleaner white appearance than control 44 (D) 5000 ppm POAA only Polyacetal A dull, cleaner white appearance than control 50 CONTROL Polyacetal A dull, dirty white material PART IV: CORROSION - RUBBERS Analytical - Observations KX-6091 CORROSION STUDY 14 day Compatibility Test of 15 different materials tested against four different Test Solutions at 50 °C with the test solutions are changed daily. lest Test Solution Material Initial Wt. Initial Ht Initial Width Initial thick Final Wt. % Weight _________ % Height Final Width % Width E__-___tu_l_ % Thick item RUBBERS (gms) (inches) (inches) (inches) .gms) nge (inches) Change (mches. Change (inches) Change 51 (A) 500 ppm Silicone 14272 2930 0928 025 4 1 4 2553 -01198 2930 00000 0933 05388 025 4 00000 POAA/Buffered 56 (B) 5000 ppm Silicone 15 5707 2 999 1007 0249 155665 -00270 2995 -01334 1008 00993 0249 00000 POAA Buffered 61 (C) 500 ppm POAA Silicone 15 6958 3 013 0995 0252 157755 05078 3019 01991 1004 09045 0252 00OO0 only 66 D) 5000 ppm POAASiIicone 15 1443 2 977 0994 0246 153760 15299 3003 06734 1005 11066 0249 12195 t only t 71 CONTROL Silicone 15 6702 2 970 1 001 0253 15 6417 -0 1819 2 970 00000 1013 11988 0254 03953 52 (A) 500 ppm Butyl 1 907 2 999 0 507 0069 1 9852 4 0789 3 008 03001 0507 00000 0071 28986 POAA/Buffered 57 (B) 5000 ppm Butyl 1 9082 2 999 0505 0069 19263 09 85 3008 03001 0505 00000 0069 00000 POAA Buffered 62 (C) 500 ppm POAA Butyl 1 9026 2 996 0505 0068 20729 89509 3017 07009 0513 15842 0075 102941 only 67 (D) 5000 ppm POAAButyl 1 9097 2 998 0507 0069 22216 163324 3029 10340 0494 -25841 0078 130435 only 72 CONTROL Butyl 1 9001 2 998 0507 0069 18939 -03263 2998 -00867 0504 -05917 0069 00000 3 (A) 500 ppm Vison 23 3725 3 057 1031 0248 234407 02918 3071 04580 1033 01940 0248 00000 POAA/Buffered 8 (B) 5000 ppm Vison 21 3847 2 98 1014 0237 214843 05598 2998 04692 1025 10848 0238 04219 POAA Buffered lesl Test Solution Material Initial Wt Initial Ht Initial Width I_____ ____ Final Wt '/. Weight Final Ht '/. Height Final Width '/. Width Final Thick '. Thick item RUBBERS (gms) (inches) (inches) .inchest fgms. Change (inches) Change (inches) Change .inches. Change 68 (D) 5000 ppm POAA Vison 22.4157 2.964 1.012 0.251 23.7728 6.0542 3.064 3.3738 1.053 4.0514 0.260 3.5857 only 73 CONTROL Vison 22.0694 2.988 .012 0.244 22.0584 -0.0498 2.991 0.1004 1.012 0.0000 0.244 0.0000 54 (A) 500 ppm EPDM 17.0399 3.042 .005 0.277 17.1763 0.8005 3.053 0.3616 1.009 0.3980 0.285 2.8881 POAA/Buffered 59 (B) 5000 ppm EPDM 16.9577 3.033 1.006 0.278 17.2265 1.5851 3.036 0.0989 1.012 0.5964 0.285 2.5180 POAA/Buffered 64 (C) 500 ppm POAA EPDM 16.9824 3.059 1.015 0.275 16.9653 -0.1007 3.068 0.2942 1.012 -0.2956 0.282 2.5455 only 69 (D) 5000 ppm POAAEPDM 17.4875 2.985 1.072 0.274 17.9757 2.7917 3.020 1.1725 1.079 0.6530 0.284 3.6496 only 74 CONTROL EPDM 16.7254 2.964 1.016 0.278 16.6918 -0.2009 2.959 -0.1687 1.015 -0.0984 0.278 0.0000 55 (A) 500 ppm BUNA 15.8678 2.960 1.006 0.242 16.3169 2.8303 2.970 0.3378 1.012 0.5964 0.247 2.0661 POAA/Buffered t 80 (B) 5000 ppm BUNA N 15.9576 2.980 1.020 0.240 16.4275 2.9447 2.989 0.3020 1.019 -0.0980 0.246 2.5000 POAA/Buffered 5 (C) 500 ppm POAA BU A N 16.2737 2.977 1.016 0.246 18.9478 4.1423 2.992 0.5039 1.024 0.7874 0.259 5.2846 only 0 (D) 5000 ppm POAABUNA N 15.8516 2.956 1.014 0.242 16.5043 4.1176 2.956 0.0000 1.029 1.4793 0.264 9.0909 only 5 CONTROL BUNA 16.0735 2.936 1.107 0.247 16.0328 -0.2532 2.937 0.0341 1.014 -0.2950 0.2 4 7 0.0000 lest Test Solution Material Visual Observations item RUBBERS 51 (A) 500 ppm POAA/Buffered Silicone A dull, med. - dark orange material similar to control 56 (B) 5000 ppm POAA/Buffered Silicone A dull, med. - dark orange material similar to control 61 (C) 500 ppm POAA only Silicone A dull, med. - dark orange material similar to control 66 (D) 5000 ppm POAA only Silicone A dull, med. - dark orange material similar to control 71 CONTROL Silicone A dull, med. - dark orange material 52 (A) 500 ppm POAA/Buffered Butyl A dull black material with sit. tacky, sit. rough t surface that stuck to drying surface resulting in loss of material 57 (B) 5000 ppm POAA/Buffered Butyl A dull black material with very sit. tacky, smooth surface 62 (C) 500 ppm POAA only Butyl A black material with tacky, dull, rough surface that stuck to drying surface resulting in loss of material 67 (D) 5000 ppm POAA only Butyl A dull black material with very tacky, very rough, surface that stuck to drying surface resulting in loss of material lest Test Solution Material Visual Observations item RUBBERS 53 (A) 500 ppm POAA/Buffered Vison A dull, charcoal black material with smooth surface 58 (B) 5000 ppm POAA/Buffered Vison A dull, charcoal black material with smooth surface 63 (C) 500 ppm POAA only Vison A dull, charcoal black material with sit. rough surface 68 (D) 5000 ppm POAA only Vison A dull, charcoal black material with sit. rough surface 73 CONTROL Vison A dull, charcoal black material with smooth surface 54 (A) 500 ppm POAA/Buffered EPDM A dull, black material with sit. rough surface 59 (B) 5000 ppm POAA/Buffered EPDM A dull, black material with sit. blistered surface 64 (C) 500 ppm POAA only EPDM A dull, black material with sit. rough surface 69 (D) 5000 ppm POAA only EPDM A dull black material with sit. rough surface t containing a large blister 74 CONTROL EPDM A dull, black material with smooth surface 55 (A) 500 ppm POAA/Buffered BUNA N A dull, (darker than control) black material with sit. rough surface 60 (B) 5000 ppm POAA/Buffered BUNA N A dark black material with very sit. shiny, fairly smooth surface 65 (C) 500 ppm POAA only BUNAN A dark black material with very sit. shiny, sit. blistered surface 70 (D) 5000 ppm POAA only BUNAN A dark black material with very sit. shiny, blistered surface 75 CONTROL BUNAN A dull, grayish black material with smooth surface I. Tuberculocidal Efficacy US Method 26 The peracetic acid product was tested against Mycobacterium bovis (BCG) using the AOAC Confirmatory Test with product concentrations as listed below. The product was diluted in buffer to achieve the pH 6 prior to test The diluent tested was either tap or distilled water. Test exposure time was 10 minutes. A result of ten no growth tubes per ten tubes tested is required for a passing result. Conclusion: successful tuberculocidal results were achieved at product concentrations as low as 1000 ppm POAA. •Oauerrt was tap or d st e wa er w p a us e o . ■Test results reflect data achieved in three test media, Proskauer-Beck, Kirshners and MkJdlebroo . II. Suspension Test - Olympus Method We have completed the suspension test as requested with the Olympus procedure versus Bacillus sυbtilis. The product was diluted in buffer to achieve the pH 6 prior to test The diluent tested was tap water. Test exposure times are listed below. The data are represented as log reduction of bacterial numbers. Note: the spores were counted after the heat shock treatment, although the test was conducted on a non-heat treated bacterial suspension. Conclusion significant log reductions in microbial numbers were achieved within 10 minutes using 500 ppm POAA. Additional product concentration or exposure time did not increase the efficacy of the product III. Carrier Test - Olympus Method We have completed the carrier test as requested using the Olympus procedure versus Bacillus subϋlis and Mycobacterium terrae . The product was diluted in buffer to achieve the pH 6 prior to test The diluent tested was tap water. Test exposure times are listed below. Note: the spores were counted after the heat shock treatment, although the test was conducted on a non- heat treated bacterial suspensions. Conclusion: successful results achieved using 250 ppm POAA within five minutes exposure against both subtilis and Mycobacterium terrae. Additional product concentration or exposure time did not increase the efficacy of the product. Number of negative carriers per number of carriers tested. 'Plate A b the average cfu ml of product phis neutralize, mixture. c Plate B b the average cfu/ml of stripper. °Neutralizer b 1% sodium thiosulfate and b effective in this test procedure for chemical neutraβzation of the test substance. IV. Sporicidal Efficacy - US Method The peracetic acid product was tested against Clostridium sporogenes using the AOAC Sporicidal Activity of Disinfectants Test with product concentrations as listed below. The product was diluted in buffer to achieve the pH 6 prior to test The diluent tested was tap water. Test exposure time was 3, 4 or 6 hours. A result of twenty no growth tubes per twenty tubes tested is required for a passing result Conclusion: successful results were achieved at 5000 ppm POAA with an exposure time of 6 hours. 'Diluent was tap or distilled water with pH adjusted to 6. * Test results reflect data achieved in three test media, Proskauer-Beck, Kirshners and Middlebrook after heat-shock treatment and reincubation for 72 hours. OBJECTTVΕ: The objective of this analysis was to evaluate the effect of hydrogen peroxide and acetic acid concentration on the sporicidal efficacy of ISO ppm peracetic acid at 40"C. TEST METHOD; Ecolab Microbiological Services SOP CB021-04; Rate of Kill Antimicrobial Efficacy. Following exposure to the formula and subsequent neutralization, spores were heat shocked for 13 minutes at 80°C before plating. METHOD PARAMETERS; Test Substances: Each formula was prepared using a "stock** POAA material (34.1 % POAA, 7.13 % H 2 0_ and 36.1 % acetic acid - Aldrich Chemical) to achieve ISO ppm POAA. H 2 0 2 or acetic acid was then added as needed. Please refer to the data sheet attached to this report for preparation information. Since chemical analyses of solutions prepared exactly like those prepared for this study were done previously, and concentrations were found to be accurate, additional chemical analysis for this study was not performed (see MSR #960351, J. Hilgren). Chemical Properties of Each Test Formula Test System: Bacillus cerevs spore crop N1009 Test Temperature: 40°C Exposure Times:0.5, 1.0, 1.5, 2.0, 2.5, 3.0 and 3.5 hours Neutralizer: Fluid Thioglycollate Medium Plating Media: Dextrose Tryptone Agar Incubation: 32°C for 48 hours RESULTS; Reduction of B. cereus Spores at 40*C Summary Chart Reduction of A cereus Spores at 40 C 0.0 hr. 0.5 hr. 1.0 hr. 1.5 hr. 2.0 hr 2.5 hr. 3.0 hr. 3.5 hr. Exposure Time (Note: The lower limit of detection for the test procedure was 10 CFU/mL) CONCLUSIONS; The sporicidal activity of 150 ppm POAA at 40 β C against Bacillus cereus spores was most effective when in the presence of relatively low concentrations of H 2 0, (» 30 ppm as in Foπnulas A and B). Reduced B. cereus sporicidal efficacy was observed using POAA with the medium and high concentrations of H 2 0 2 (» 160 and 300 ppm as in Foπnulas C through F). OBJECTIVE: The objective of this analysis was to evaluate the effect of hydrogen peroxide and acetic acid concentration on the sporicidal efficacy of 150 ppm peracetic acid at 60°C. TEST METHOD: Ecolab Microbiological Services SOP CB021-04; Rate of Kill Antimicrobial Efficacy. Following exposure to the formula and subsequent neutralization, spores were heat shocked for 13 minutes at 80°C before plating. METHOD PARAMETERS; Test Substances: Each formula was prepared using a "stock** POAA material (34.1 % POAA, 7.13 % H 2 0 2 and 36.1 % acetic acid - Aldrich Chemical) to achieve ISO ppm POAA. H 2 0 2 or acetic acid was then added as needed. Please refer to the data sheet attached to this report for theoretical concentrations and preparation information. Analytical Chemistry Results - A&P Methods 9403201, 9600300 * No obvious error in analysis was detected, but the result remains in question. Test System: Bacillus cereus spore crop N1009 Test Temperature: βVC Exposure Times: 10, 15, 20, 25, 30 and 40 minutes Neutraiizer: Fluid Thiσglycollate Medium Plating Media: Dextrose Tryptone agar Incubation: 32°C for 48 hours RESULTS; Inoculum Numbers Reduction of B. cereus Spores at 60'C Summary Chart Reduction of B. cereus Spores at 60 C O min. 10 min. 15 min. 20 min. 25 min Exposure Time (Note: The lower limit of detection for the test procedure was 10 CFU/mL) CONCLUSIONS: The sporicidal activity of 150 ppm POAA at 60*C against Bacillus cereus spores was most effective when in the presence of relatively low concentrations of H 2 0 2 (« 30 ppm as in Formulas A and B). A decrease in B. cereus sporicidal efficacy was observed using the medium and high concentrations of H 2 0 2 (« 160 and 300 ppm as in Formulas C through F). Further testing using Foπnulas A - F will be conducted at 20°C to determine the effect of H 2 0 2 and acetic acid concentration on sporicidal efficacy of POAA at low temperature. OBJECTIVE; The objective of this analysis was to evaluate the effect of hydrogen peroxide, octanoic acid and peroctanoic acid concentration on the sporicidal efficacy of 150 ppm peracetic acid at 40°C. TEST METHOD: Ecolab Microbiological Services SOP CB021-04; Rate of Kill Antimicrobial Efficacy. Following exposure to the formula and subsequent neutralization, spores were heat shocked for 13 minutes at 80°C before plating. METHOD PARAMETERS; Test Substances: Each formula was prepared using a "stock" POAA material (33.5 % POAA, 7.03 % H 2 0 2 and 37.2 % acetic acid - Aldrich Chemical) and a "stock** octanoic/peroctanoic material (11.4% octanoic, 3.4% POOA, 10.29% POAA, 3.70% HA - Falcon 15). Hydrogen peroxide, octanoic acid or peroctanoic acid were then added as needed. Please refer to the data sheet attached to this report for preparation information. Prior to this study, chemical analyses of formulas exactly like those used for this study were conducted to determine if ingredient concentrations were close to theoretical and if they were stable over the duration of the efficacy test Results showed ingredient concentrations to correlate with theoretical and to be stable. Chemical Properties of Each Test Formula Test System: Bacillus cereus spore crop N1009 Test Temperature: 40°C Exposure Times:5, 10, 15, 20, 25 and 30 minutes Neutralizer: Fluid Thioglycollate Medium Plating Medium:Dextrose Tryptone Agar Incubation: 32°C for 48 hours RESULTS: Inoculum Numbers Inoculum Test Replicate (CFU/mL) . _. Organism 1 | 2 | 3 Average (CFU/mL) " B. cereus Spores 56xiσ f> | 42x100 1 35x100 4.4x10' Reduction of B. cereus Spores at 40'C Reduction of B. cereus Spores at 40 C O min. 5 min. 10 min. IS min. 20 min. 25 min. 30 min. Exposure Time (Note: The lower limit of detection for the test procedure was 10 CFU/mL) CONCLUSIONS; Effect of HA: The sporicidal activity of 150 ppm POAA at 40°C against Bacillus cereus spores was most effective when in the presence of relatively low concentrations of H 2 0 2 (» 36 ppm as in Formulas 1, 3, 5 and 7). Reduced B. cereus sporicidal efficacy was observed using POAA with the higher concentrations of H 2 0 2 (» 529 ppm as in Formulas 2, 4, 6 and 8). Effects of Octanoic and Peroctanoic Acid: The sporicidal activity of 150 ppm POAA at 40"C against Bacillus cereus spores increased when the concentrations of octanoic or peroctanoic acid increased. This phenomenon was clearly evident in formulas containing the high concentrations of H 2 0 2 (foπnulas 2, , 6 and 8). On a weight basis, peroctanoic acid had a greater effect on the sporicidal efficacy of 150 ppm POAA against B. cereus than octanoic acid. An increase of 38 ppm POOA resulted in a greater log reduction of B. cereus spores than an increase of 99 ppm octanoic acid. An additive effect was observed when POOA and octanoic acid were combined.

Claims: WHAT IS CLAIMED: 1. A method of sterilizing an article comprising mixing a first and a second solution to form a sterilizing solution comprising an aqueous solution of a peroxy acid, said first solution comprising a carboxylic acid, hydrogen peroxide and water, and said second solution comprising a buffering agent for pH between about 5 and 7, said sterilizing solution comprising at least 100 parts per million of peroxy acid at a pH of 5 to 7, immersing said article in said sterilizing solution for at least 5 minutes to sterilize said article. 2. The method of claim 1 wherein said solution also comprises a catalytic amount of a catalyst for peroxidation of said carboxylic acid by said hydrogen peroxide. 3. The method of claim 1 wherein said sterilizing solution has no effective amount of an organic copper or brass corrosion inhibiting compounds therein. 4. The method of claim 1 wherein said buffering agent comprises phosphate ion. 5. The method of claim 1 wherein said buffering agent comprises trisodium phosphate. 6. The method of claim 1 wherein said peroxy acid comprises a peroxy acid of at least one Cl to C12 carboxylic acid. 7. The method of claim 1 wherein said peroxy acid comprises a peroxy acid of at least one Cl to C8 carboxylic acid. 8. The method of claim 1 wherein said sterilization solution comprises 1000 to 5000 parts per million of at least one peroxy acid. 9. The method of claim 1 wherein said peroxy acid is selected from the group consisting of performic acid, peracetic acid, perpropionic acid, perbutanoic acid, perpentanoic acid, perhexanoic acid, perheptanoic acid, peroctanoic acid, pernonanoic acid, perundecanoic acid, and perdecanoic acid. 10. The method of claim 2 wherein said peroxy acid is selected from the group consisting of peracetic acid, performic acid, perpropionic acid, perbutanoic acid, perpentanoic acid, perhexanoic acid, perheptanoic acid, peroctanoic acid, pernonanoic acid, and perdecanoic acid. 11. The method of claim 8 wherein said peroxy acid is selected from the group consisting of performic acid, peracetic acid, perpropionic acid, perbutanoic acid, perpentanoic acid, perhexanoic acid, perheptanoic acid, peroctanoic acid, pernonanoic acid, perundecanoic acid, and perdecanoic acid. 12. The method of claims 2, 9 and 10 wherein said sterilizing solution has no effective amount of an organic copper or brass corrosion inhibiting compounds therein. 13. The method of claim 1 wherein said first solution also comprises a peroxycarboxylic acid. 14. The method of claim 1 wherein said buffering agent comprises acetic acid and sodium acetate. 15. An aqueous sterilant solution having a pH of from 5.0 to 7.0 comprising from 100 to 10,000 parts per million of a peroxy acid and 30 to 5000 parts per million of buffering agent. 16. An aqueous sterilant solution according to claim 15 having a pH of from 5.0 to 7.0 comprising from 100 to 10,000 parts per million of a peroxy acid, 30 to 5000 parts per million of buffering agent and a catalytically effective amount of a catalyst for peroxygenation of a carboxylic acid by hydrogen peroxide. 17. An aqueous sterilant solution according to claim 15 consisting essentially of a solution having a pH of from 5.0 to 7.0 comprising from 100 to 10,000 parts per million of a peroxy acid, 30 to 5000 parts per million of buffering agent and a catalytically effective amount of a catalyst for peroxygenation of a carboxylic acid by hydrogen peroxide. 18. An aqueous sterilant solution according to claim 15 consisting essentially of a solution having a pH of from 5.0 to 7.0 comprising from 100 to 10,000 parts per million of a peroxy acid, 30 to 5000 parts per million of buffering agent, a chelating agent for cations, and a catalytically effective amount of a catalyst for peroxygenation of a carboxylic acid by hydrogen peroxide. 19. The method of claim 1 comprising mixing a first and a second solution to form a sterilizing solution comprising a peroxy acid, said first solution comprising a carboxylic acid, hydrogen peroxide and water, and said second solution comprising a buffering agent for pH between about 5 and 7, said sterilizing solution comprising at least 100 parts per million of peroxy acid at a pH of 5 to 7, immersing said article in said sterilizing solution for at least 5 minutes to sterilize said article, said first solution and second solution being free of organic anti-corrosion agents for brass and/or copper, and said article comprising a medical article having parts made of at least two materials selected from the group consisting of metals, polymers and rubbers. 20. The method of claim 1 wherein said carboxylic acid is at least one carboxylic acid selected from the group consisting of aliphatic carboxylic acids, aromatic carboxylic acids, mono- and di-hydroxycarboxylic acids diacids, and peroxycarboxylic acids is present within said first solution. 21. The method of claim 1 wherein said carboxylic acid is at least one carboxylic acid selected from the group consisting of hydroxy acids and dicarboxylic acids.

Inventors: REINHARDT DUANE J, RICHTER FRANCIS L, SWART SALLY K, REINHARDT, DUANE, J., RICHTER, FRANCIS, L., SWART, SALLY, K.
Applicants: ECOLAB INC, ECOLAB INC.
Application year: 1999
Main classification: A61L2
IPC codes: A01N37, A61L2