Improved endoscope disinfectant

Abstract

To provide a disinfectant operation solution for use in disinfection or sterilization of reusable medical equipment, such as an endoscope.SOLUTION: A disinfectant operation solution includes peracetic acid and at least one kind of surfactant, which is prepared by dilution of either 1 part or 2 parts concentrated liquid. The operation solution shows rapid wetness characterized by dynamic surface tension of 50 mN / m at 250 ms and 46 mN / m at 500 ms.SELECTED DRAWING: Figure 3

Description

Detailed Description of the Invention

[0001]

[0001] [Background]

[0002] Reusable medical devices are devices that can be reprocessed and reused by healthcare providers for multiple patients. Examples of reusable medical devices include surgical forceps, endoscopes, and stethoscopes.

[0002]

[0003] Reusable medical devices can be grouped into one of three categories according to the risk of infection associated with the use of the device: Critical devices (such as surgical forceps) come into contact with blood or normally sterile tissue. Semicritical devices (such as endoscopes) come into contact with mucous membranes. Noncritical devices (such as stethoscopes) come into contact with intact skin.

[0003]

[0004] This classification system was devised by Erwin Spaulding and serves as a guide for the reprocessing of reusable medical devices.

[0004]

[0005] Critical medical devices should ideally be reprocessed by sterilization by moist heat, or by other means if the device is incompatible with moist heat. Semicritical medical devices should also be sterilized by moist heat if possible, but at least by exposure to a high-level disinfectant.

[0005]

[0006] Chemical sterilants are chemical agents used for the sterilization of critical medical devices. Sterilants kill all microorganisms, resulting in a sterilization assurance level, i.e., the probability of survival of a single microorganism is 10 -6 or less. High-level disinfectants (HLD) can be considered a subcategory of sterilants, but the exposure time is shorter than that required for sterilization. HLD kills all microbial pathogens except for a large number of bacterial endospores when used as recommended by the manufacturer, and is the minimum treatment recommended for the reprocessing of semicritical medical devices.

[0006]

[0007] Common types of semi-critical medical devices are flexible endoscopes such as colonoscopes and gastroscopes. Due to their complex structures and the use of heat-unstable materials such as polyurethane sheaths, epoxy coatings, fiber optic cables, and optical chips, most flexible endoscopes cannot be sterilized by wet heating and are therefore reprocessed using chemical sterilants or high-level disinfectants.

[0007]

[0008] A well-regarded option for both chemical sterilization and high-level disinfection of flexible endoscopes is peracetic acid (PAA).

[0008]

[0009] PAA is usually supplied as an equilibrium mixture of PAA, hydrogen peroxide, and acetic acid. PAA is prepared by mixing aqueous solutions of hydrogen peroxide and acetic acid and allowing the materials to reach equilibrium. Typically, this reaction is carried out without a catalyst, allowing the reactants to reach equilibrium over 10 - 14 days, or it may be catalyzed by adding a strong mineral acid such as 1% w / w concentrated sulfuric acid.

[0009]

[0010] Commercial grade PAA is commercially available containing 5.0 - 5.4% PAA. This PAA concentration is generally classified as a Class 5.1 dangerous good for commercial transactions. Products with higher concentrations of PAA are classified as Class 5.2 dangerous goods, which has an adverse impact on transportation costs and storage requirements.

[0010]

[0011] Typically, a 5.0 - 5.4% w / w PAA equilibrium solution also contains approximately 25 - 28% w / w hydrogen peroxide and 7 - 10% w / w acetic acid. Often, a phosphonic acid chelating agent is added to prevent product degradation by trace metal contaminants.

[0011]

[0012] PAA is generally used as a sterilant or HLD for the reprocessing of flexible endoscopes using an automated endoscope washer or AER. The reprocessing of endoscopes in an AER typically involves the following steps: Placement into the AER Preliminary cleaning with water Phase cleaning with a suitable detergent Rinsing of phases using water Sterilization or disinfection Multiple rinses are required.

[0012]

[0013] AER injects a PAA sterilizing or disinfecting agent into the room containing the endoscope and dilutes it to the working concentration. For high-level disinfection, a 5% w / w PAA stock solution is typically diluted to 1 - 2% v / v, while for sterilization, it is diluted to 2 - 4% v / v. This results in a working concentration of PAA of approximately 650 - 1000 ppm for high-level disinfection and 1300 - 2000 ppm for sterilization.

[0013]

[0014] Apart from the PAA concentration, the time required to achieve disinfection is also determined by the temperature of the disinfecting or sterilizing agent. For flexible endoscopes, typically a temperature of 25°C - 40°C for 5 minutes is used for high-level disinfection, while for sterilization, a contact time of 7 - 10 minutes at a temperature of 30°C - 45°C is common.

[0014]

[0015] One problem associated with the use of PAA for endoscope disinfection and sterilization is corrosion of the endoscope and / or AER by the strongly acidic and oxidizing PAA. This is usually mitigated to some extent by adding corrosion inhibitors and pH buffers to the diluted PAA solution. Commonly used corrosion inhibitors include benzotriazole, potassium phosphate, sodium nitrite, sodium nitrate, molybdenum salts, etc.

[0015]

[0016] Corrosion inhibitors and pH buffers are typically added as separate solutions, as part B of the AER disinfection chamber (where the concentrated PAA solution is part A). This configuration can be referred to as a two-part disinfecting or sterilizing agent. Other components, such as wetting agents like surfactants, may also be added to part B. Surfactants are added to properly wet the surface of the endoscope with the disinfectant and solubilize any remaining dirt from the cleaning phase.

[0016]

[0017] Typically, non-ionic surfactants are used in the Part B solution because, typically, they have low foaming properties. Examples include Pluronic 10R5 (see, e.g., WO2016 / 100818 by Medivators), Pluronic PE85 and PE64 (see, e.g., U.S. Patent No. 20030129254 by Saraya). The use of Pluronic surfactants in the Part B formulation is also taught by JP2009155270 of Fujifilm Corporation. Note that there is no teaching regarding the surface tension of the disinfectant solution prepared from these formulations.

[0017]

[0018] The use of amine oxide surfactants in combination with other surfactants has been shown to enhance the bactericidal efficacy of PAA-based disinfectants, particularly when combined with phosphate buffer solutions. This is shown in AU2013359955 (by Saban Ventures). The surfactants tested included cocamidopropylamine oxide. Other non-ionic surfactants such as Triton X-100 or Tween-80 were also tested. The cationic surfactants tested included quaternary ammonium compounds such as benzalkonium chloride or cetylpyridinium bromide.

[0018]

[0019] The use of amine oxide-based surfactants has also been shown to improve the bactericidal efficacy of PAA-based disinfectants, particularly when combined with surfactants having the structure shown in Chemical Formula 1. R1-O-[CH(R2)-CH(R3)-O] n -R4 Chemical Formula 1 (In the formula, R1 represents a linear or branched saturated or unsaturated aliphatic group containing 5 to 31 carbon atoms, preferably 10 to 16 carbon atoms; R2 represents a hydrogen atom, a methyl group or an ethyl group; R3 represents a hydrogen atom, a methyl group or an ethyl group; it is understood that at least one of the two groups R2 and R3 represents a hydrogen atom; R4 represents a hydrogen atom or a linear or branched alkyl group containing 1 to 4 carbon atoms, or a benzyl group; n represents a number from 1 to 50, preferably n is less than 20 (see U.S. Patent No. 6,168,808, U.S. Patent No. 6,444,230, and FR2796285 (all by Sppic)).

[0019]

[0020] A proposal for the mechanism responsible for the improvement in the bactericidal efficacy of PAA in the presence of a surfactant is the improved wetting of the disinfectant in the presence of the surfactant system. For example, European Patent No. 0,971,584 (also by Seppic) shows that a PAA-based disinfectant formulated with an amine oxide surfactant, especially in the presence of a surfactant having the structure shown in Chemical Formula 1, has a static surface tension of about 26.5 to 31.0 mN / m when measured using the Wilhelmy plate method and can exhibit good wetting properties with respect to dilution.

[0020]

[0021] Interestingly, according to the regeneration of these formulations and the measurement of their surface tension by the maximum bubble pressure method, the examples of European Patent No. 0,971,584 demonstrate that the wetting of these formulations is slow and that they have a surface tension significantly higher than the static values reported in the literature of European Patent No. 0,971,584 (see Examples 9 and Figure 6) with a surface lifetime of 15,000 ms.

[0021]

[0022] The discussion of documents, statutes, materials, equipment, articles, etc. is included in this specification only for the purpose of providing the context of the present invention. None or all of these contents are suggested or represented as having existed prior to the priority date of each claim of this application and thus forming part of the basis of the prior art or being common general knowledge in the field related to the present invention.

[0022]

[0023] [Summary of the Invention]

[0024] According to a first embodiment of the present invention, there is provided a disinfectant working solution for sterilizing or disinfecting medical devices, comprising an aqueous dilution of a disinfectant concentrate containing (a) peracetic acid and (b) at least one surfactant, which exhibits a dynamic surface tension of less than about 50 mN / m with a surface lifetime of 250 ms and less than about 46 mN / m with a surface lifetime of 500 ms when measured by the maximum bubble pressure method at 20 - 25°C.

[0023]

[0025] According to a second embodiment of the present invention, there is provided the disinfectant working solution of the first embodiment, which exhibits a dynamic surface tension of less than about 42.5 mN / m with a surface lifetime of 250 ms and less than about 41.0 mN / m with a surface lifetime of 500 ms at 20 - 25°C when measured by the maximum bubble pressure method.

[0024]

[0026] According to a third embodiment of the present invention, there is provided the disinfectant working solution of the second embodiment, which also exhibits a dynamic surface tension of less than about 40 mN / m with a surface lifetime of 5000 ms when measured by the maximum bubble pressure method.

[0025]

[0027] According to a fourth embodiment of the present invention, there is provided a disinfectant working solution according to any one of the first, second or third embodiments, wherein the disinfectant concentrate is provided as a single - part disinfectant concentrate.

[0026]

[0028] According to a fifth embodiment of the present invention, there is provided a disinfectant working solution according to any one of the first, second or third embodiments, wherein the disinfectant concentrate is provided as a two - part disinfectant concentrate having a first part and a second part.

[0027]

[0029] According to a sixth embodiment of the present invention, there is provided a method for disinfecting or sterilizing a medical device, the method comprising contacting the medical device with a disinfectant working solution comprising an aqueous dilution of a disinfectant concentrate containing (a) peracetic acid and (b) at least one surfactant, wherein the disinfectant working solution exhibits a dynamic surface tension of less than about 50 mN / m with a surface lifetime of 250 ms and less than about 46 mN / m with a surface lifetime of 500 ms when measured by the maximum bubble pressure method at 20 to 25 °C.

[0028]

[0030] According to a seventh embodiment of the present invention, there is provided a method for disinfecting or sterilizing a medical device, the method comprising contacting the medical device with a disinfectant working solution according to any one of the first to fifth embodiments.

[0029]

[0031] Throughout the description and claims of this specification, the word "comprise" and variations of the word (such as "comprising" and "comprises") are not intended to exclude other additives, components, integers or steps.

Brief Description of the Drawings

[0030]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

[0031]

[0044] [Detailed Description of the Invention]

[0045] This specification describes a PAA - based disinfectant composition intended for use in the high - level disinfection and / or sterilization of reusable heat - labile complex medical devices such as flexible endoscopes. The described composition is typically manufactured as a concentrate and then diluted to a preferred working concentration at the time of use. The diluted disinfectant composition is referred to herein as the disinfectant working solution.

[0032]

[0046] Preferably, the disinfectant working solution of the present invention is used in an automatic washer - disinfector, more preferably an automatic washer - disinfector for the re - processing of, for example, flexible endoscopes.

[0033]

[0047] The disinfectant working solution of the present invention is formed by diluting a disinfectant concentrate.

[0034]

[0048] In one embodiment, the disinfectant concentrate consists of two parts. The first part is preferably a PAA concentrate, and the second part is preferably a corrosion inhibitor concentrate containing at least one surfactant. The first part (referred to as part A) contains an equilibrium solution of PAA, hydrogen peroxide and acetic acid, preferably in combination with a stabilizer and optionally a small amount of strong mineral acid. The second part (referred to as part B) preferably contains at least one corrosion inhibitor, at least one surfactant, and may optionally contain other components such as hydrotropes, pH adjusters, indicators, colorants, chelating agents, etc. The disinfectant working solution is formed by mixing part A and part B and diluting with water to obtain the required concentration of PAA.

[0035]

[0049] Preferably, part A is an equilibrium solution containing from about 0.1% w / w to about 20% w / w of PAA. More preferably, part A contains from about 1% w / w to about 15% of PAA. Most preferably, part A contains from about 4% w / w to about 6% w / w of PAA.

[0036]

[0050] Note that commercially available PAA equilibrium solutions (such as Proxitane) contain stabilizers (which are often essentially proprietary). These commercial products may also contain small amounts (typically 1% or less) of mineral acids (especially when manufactured in cold climates).

[0037]

[0051] The second part (hereinafter referred to as part B) contains an aqueous solution of at least one surfactant, preferably at least one corrosion inhibitor and / or at least one pH adjuster.

[0038]

[0052] Accordingly, the disinfectant working solution of the present invention is produced by combining part of the part A and part B solutions with water to produce an aqueous disinfectant working solution.

[0039]

[0053] Preferably, the ratio of Part A to Part B is from about 1:10 to about 10:1 by volume weight. More preferably, the ratio of Part A to Part B is from about 1:5 to about 5:1 by volume weight. Most preferably, the ratio of Part A to Part B is about 1:1 by volume weight.

[0040]

[0054] The disinfectant working solution preferably contains about 0.1% v / v to about 10% v / v of Part A and about 0.1% v / v to about 10% v / v of Part B. More preferably, for high-level disinfection, the disinfectant working solution contains about 0.5% v / v to about 5% v / v of Part A and about 0.5% v / v to about 5% v / v of Part B, and for sterilization, it contains about 1.0% v / v to about 10% v / v of Part A and about 1.0% v / v to about 10% v / v of Part B.

[0041]

[0055] When measured by the maximum bubble pressure method, the disinfectant working solution exhibits a dynamic surface tension of less than about 50 mN / m at a surface lifetime of 250 ms and less than about 46 mN / m at a surface lifetime of 500 ms at 20 - 25°C.

[0042]

[0056] In a preferred embodiment, when measured by the maximum bubble pressure method, the disinfectant working solution exhibits a dynamic surface tension of less than about 42.5 mN / m at a surface lifetime of 250 ms and less than about 41 mN / m at a surface lifetime of 500 ms at 20 - 25°C.

[0043]

[0057] In another preferred embodiment, when measured by the maximum bubble pressure method, the disinfectant working solution exhibits a dynamic surface tension of less than about 42.5 mN / m at a surface lifetime of 250 ms, less than about 41 mN / m at a surface lifetime of 500 ms, and less than about 40 mN / m at a surface lifetime of 5000 nm at 20 - 25°C.

[0044]

[0058] In another embodiment of the present invention, the disinfectant concentrate is provided as a single-part disinfectant composition comprising at least an equilibrium solution of PAA, hydrogen peroxide and acetic acid and at least one surfactant, preferably in combination with a stabilizer. Optionally, the single-part disinfectant concentrate may also contain at least one corrosion inhibitor and other components such as hydrotropes, pH adjusters, indicators, colorants, chelating agents, etc. In use, the single-part disinfectant concentrate is preferably diluted with water.

[0045]

[0059] The diluted single-part disinfectant concentrate is a disinfectant working solution that exhibits a dynamic surface tension of less than about 50 mN / m at a surface lifetime of 250 ms and less than about 46 mN / m at a surface lifetime of 500 ms at 25 - 25 °C as measured by the maximum bubble pressure method.

[0046]

[0060] In a preferred embodiment, this diluted single-part disinfectant concentrate that forms the disinfectant working solution of the present invention exhibits a dynamic surface tension of less than about 42.5 mN / m at a surface lifetime of 250 ms and less than about 41 mN / m at a surface lifetime of 500 ms at 20 - 25 °C as measured by the maximum bubble pressure method.

[0047]

[0061] In another preferred embodiment, the diluted single-part disinfectant concentrate that forms the disinfectant working solution exhibits a dynamic surface tension of less than about 42.5 mN / m at a surface lifetime of 250 ms, less than about 41.0 mN / m at a surface lifetime of 500 ms, and less than about 40.0 mN / m at a surface lifetime of 5000 nm at 20 - 25 °C as measured by the maximum bubble pressure method.

[0048]

[0062] Without wishing to be bound by theory, the improved rapid wetting brought about by the low surface tension at low surface lifetimes is thought to enable more rapid disinfection of endoscopes inside AER, especially those using dynamic cleaning processes such as spray arms.

[0049]

[0063] The improved performance of the disinfectant resulting from the rapid wetting of the disinfectant working solution of the present invention provides at least 6 log reduction in both bacteria and spores compared to prior art PAA-based disinfectant solutions when tested under the same conditions of PAA concentration and temperature. 10 It provides for a more rapid achievement of reduction.

[0050]

[0064] Alternatively, or in addition, the disinfectant working solution of the present invention provides at least 6 log reduction in both bacteria and spores within the same time frame as prior art PAA-based disinfectant solutions when tested at a lower PAA concentration. 10 The lower concentration results in a less corrosive disinfectant solution, but the bactericidal performance is equivalent.

[0051]

[0065] Much of the prior art describes both single-part and two-part PAA-based disinfectants containing surfactants, and the presence of the surfactant can result in an increase in the bactericidal efficacy of the PAA-based disinfectant.

[0052]

[0066] As described above, it has been suggested that the presence of the surfactant improves the wetting of the surface by the disinfectant and thus leads to improved disinfecting efficacy. European Patent No. 0971584 describes wetting that shows promise for improvement in terms of the low surface tension of the disinfectant leading to a lower contact angle of the solution on hydrophobic surfaces such as parafilm. However, European Patent No. 0971584 in the literature characterized the static surface tension of the solution using the Wilhelmy plate method (see Table 1). Data on the dynamic surface tension was not reported in European Patent No. 0971584 literature.

Table 1

[0053]

[0067] Figure 3 shows a comparison of the dynamic surface tensions over the range of surface lifetimes between several prior art PAA-based disinfectant examples and an exemplary embodiment of the disinfectant working solution of the present invention. As can be clearly seen, all exemplary embodiments exhibit a characteristically rapid achievement of surface tensions of less than about 42.5 mN / m, as compared to prior art examples that reach surface tensions of less than 40 mN / m by 5000 ms.

[0054]

[0068] The Wilhelmy plate typically consists of a thin plate with an area of approximately several square centimeters (see Figure 1). The plate is often made of filter paper, glass, or platinum that can be roughened to ensure complete wetting. In fact, experimental results are independent of the material used as long as the material is wetted by the liquid. The plate is thoroughly cleaned and attached to a scale with a thin metal wire. The force exerted on the plate by wetting is measured using a tensiometer or a microbalance, and this force is used in the Wilhelmy equation:

Number

[0055]

[0069] One problem with the Wilhelmy plate method is that it represents a static case. When a surfactant is dissolved in water, the surfactant molecules move to the surface of the liquid (either at the air interface or to the walls of the container). Until a certain concentration of surfactant (the critical micelle concentration or CMC) is reached, all the molecules of the surfactant move to the various surfaces surrounding the solution. Once the CMC is exceeded, aggregates of surfactant molecules (micelles) form in the bulk solution.

[0056]

[0070] The diffusion rate of surfactant molecules from the bulk solution to the surface interface varies depending on the type of surfactant, which is manifested, for example, in the wetting rate.

[0057]

[0071] When measured by the Wilhelmy plate method (or a similar method such as the DeNoy ring), the solution being measured is not stirred and represents the static or equilibrium surface tension, i.e., the surface tension achieved when all available surfactant molecules have migrated to the interface.

[0058]

[0072] The measured values are valid for the assessment of disinfectants used under static conditions (i.e., for example, when an endoscope is immersed in a static solution of the disinfectant), but this is not typically done with the latest AERs that typically pump the disinfectant solution continuously through the endoscope lumen and spray the disinfectant onto the outer surface of the endoscope using a spray arm. This creates a very dynamic environment where the disinfectant is constantly mixed. Under these conditions, with a slowly diffusing surfactant system, the actual surface tension is significantly higher than that measured using a static method such as the Wilhelmy plate.

[0059]

[0073] [Dynamic Surface Tension Measurement]

[0074] One method for measuring dynamic surface tension is the maximum bubble pressure method. Due to the internal attraction of the liquid, the bubbles in the liquid are compressed. As the bubble radius decreases, the resulting pressure (bubble pressure) increases. The bubble pressure method uses this bubble pressure that is higher than in the surrounding environment (water). An air stream is pumped into a capillary immersed in the fluid. The bubbles obtained at the capillary tip continue to grow in surface area.

[0060]

[0075] The pressure rises to a maximum level. At this point, the bubble reaches its minimum radius (capillary radius) and forms a hemisphere. Beyond this point, the size of the bubble rapidly increases and it immediately ruptures and is peeled off from the capillary, thereby creating a new bubble at the capillary tip. During this process, a characteristic pressure pattern is established (see Figure 2) and the determination of surface tension is evaluated.

[0061]

[0076] Due to the variation in the bubble formation rate, the surface tension can be determined over a range of surface lifetimes, and the surface tension can be measured with a longer surface lifetime approaching the value measured under static conditions.

[0062]

[0077] Thus, the use of the maximum bubble pressure method enables the determination of surface tension under dynamic conditions (such as those faced in the latest AER).

[0063]

[0078] [Disinfectant components]

[0079] (Peracetic acid solution)

[0080] In a preferred embodiment, the disinfectant concentrate of the present invention is prepared using an equilibrium solution containing PAA, hydrogen peroxide, acetic acid, and water, containing about 0.1 to about 20% w / w of PAA. In a more preferred embodiment, the PAA solution preferably contains about 1% to 15% w / w, more preferably about 4% w / w to about 6% w / w of PAA.

[0064]

[0081] Typically, the PAA solution is supplied as an equilibrium solution. These solutions are prepared by reacting hydrogen peroxide and acetic acid, as shown in Equation 2. CH3COOH + H2O2 ⇔ CH3COOOH + H2O Equation 2

[0065]

[0082] The reaction mixture usually also contains a stabilizer, which is typically a chelating agent that functions to complex heavy metal ions, in order to prevent the catalysis of the decomposition of peroxide species by heavy metal ions.

[0066]

[0083] The reaction to form PAA may be left uncatalyzed, in which case the reaction may take 10 to 15 days to reach equilibrium, or it may be catalyzed by adding a small amount (about 1% w / w) of a strong acid (such as sulfuric acid). At equilibrium, the final solution consists of a mixture containing both reactants and products (i.e., a mixture containing PAA, water, hydrogen peroxide, and acetic acid). The equilibrium solution can be prepared using known methods (e.g., the method of F.P. Greenspan, "The Convenient Preparation of Per-acids", J. Am. Chem. Soc. 1946, 68, 5, 907 - 907).

[0067]

[0084] The degree of the reaction can be defined by the equilibrium constant k, which is the molar concentration ratio of the product to the reactant, that is, [Number] it can be defined by Rearranging this equation gives the following equation [Number] (wherein: k is the equilibrium constant, [PAA] is the molar concentration of PAA, [Water] is the molar concentration of water, [HP] is the molar concentration of hydrogen peroxide, [AcOH] is the molar concentration of acetic acid).

[0068]

[0085] At room temperature, the value of the equilibrium constant is about 2.7 (see, for example, Zhao et al., "Preparation of Peracetic Acid from Acetic Acid and Hydrogen Peroxide: Experimentation and Modelling", The Chinese Journal of Process Engineering, 8(1), 35 - 41, (2008)).

[0069]

[0086] As can be confirmed by Equation 4, in the solution, the molar concentration of PAA is directly proportional to the product of the molar concentrations of hydrogen peroxide and acetic acid and inversely proportional to the molar concentration of water. Therefore, as long as the product of the molar concentrations of hydrogen peroxide and acetic acid remains constant, the equilibrium solution containing PAA at a specified concentration can contain hydrogen peroxide and acetic acid at different concentrations.

[0070]

[0087] The PAA composition may also contain other components such as stabilizers and mineral acids. The stabilizer can be selected from the group consisting of phosphonic acid derivatives such as aminotri(methylenephosphonic acid), 1 - hydroxyl ethylidene - 1,1 - diphosphonic acid, quinolin - 8 - ol, 2,6 - pyridinedicarboxylic (dipicolinic) acid, aspartic acid, diethoxy succinate, quinoline - 2 - carboxylic acid, citric acid, isocitric acid, aconitic acid, propane - 1,2,3 - tricarboxylic acid, and mixtures thereof. The mineral acid can be selected from the group consisting of sulfuric acid, nitric acid, methanesulfonic acid, trifluoromethanesulfonic acid, and mixtures thereof.

[0071]

[0088] In yet another embodiment, the composition containing PAA of the present invention can be formed by the reaction between a hydrogen peroxide solution and an acylating agent such as tetraacetyl ethylene diamine (TAED), N - acetyl caprolactam, N - acetyl succinimide, N - acetyl phthalimide, N - acetyl maleimide, pentaacetyl glucose, octaacetyl sucrose, acetyl salicylic acid, tetraacetyl glycoluril, and combinations thereof.

[0072]

[0089] When diluted for use, the concentration of PAA in the disinfectant working solution is preferably about 0.01% w / v to about 1.0% w / v (about 100 ppm to about 10,000 ppm), more preferably about 0.02% w / v to about 0.5% w / v (200 ppm to about 5000 ppm).

[0073]

[0090] As those skilled in the art will recognize, other peracids may be used together with peracetic acid or in place of peracetic acid. Examples of other peracids include, but are not limited to, percitric acid, perlactic acid, performic acid, perpropionic acid, perhexanoic acid, perheptanoic acid, peroctanoic acid, perbenzoic acid, and mixtures thereof.

[0074]

[0091] (Corrosion inhibitor)

[0092] Preferably, the disinfectant composition of the present invention contains corrosion inhibitors such as, but not limited to, benzotriazole, alkali metal phosphates, alkali metal nitrates, alkali metal nitrites, 2-phosphonobutane-1,2,4-tricarboxylate, metal molybdates, and combinations thereof.

[0075]

[0093] The corrosion inhibitor reduces corrosion caused by the disinfectant composition of the present invention in both the endoscope and the endoscope cleaning and disinfection device. Preferably, the corrosion inhibitor is present in an amount of about 0.1% w / v to about 2% w / v in the disinfectant concentrate or about 500 ppm to about 5000 ppm in the diluted standard disinfectant solution.

[0076]

[0094] In one embodiment, the corrosion inhibitor is included in Part B of the two-part disinfectant concentrate. In another embodiment, the corrosion inhibitor is included in the peracetic acid solution of the single-part concentrate.

[0077]

[0095] (Surfactant)

[0096] Suitable surfactants for use in the disinfectant working solution of the present invention include ionic, non-ionic, zwitterionic, and amphoteric surfactants, or mixtures thereof. Preferably, the surfactant or surfactant mixture has low foaming properties and also functions as a wetting agent.

[0078]

[0097] The surfactant(s) is preferably present in the disinfectant working solution in an amount of about 0.005% w / v to 0.5% w / v.

[0079]

[0098] Preferably, the surfactant(s) is present in the disinfectant working solution in an amount of about 0.01% w / v to 0.4% w / v.

[0080]

[0099] In the two-part disinfectant concentrate, the surfactant(s) is preferably present in an amount of about 0.05% to about 15% w / w, more preferably about 0.1% to about 10% w / w, of the Part B composition.

[0081]

[0100] In the single-part disinfectant concentrate, the surfactant(s), preferably, is / are present in an amount of about 0.05% to about 15% w / w, more preferably about 0.1% to about 10% w / w of the single-part disinfectant concentrate.

[0082]

[0101] Ideally, the surfactant(s) also enables rapid wetting of the surface. In a preferred embodiment, the surfactant is selected to produce a disinfectant working solution having a Draves wetting time of less than 40 seconds.

[0083]

[0102] In a preferred embodiment, the surfactant is selected to produce a disinfectant working solution having a dynamic surface tension of less than about 42.5 mN / m at a surface lifetime of 250 ms and less than about 41 mN / m at a surface lifetime of 500 ms, as measured by the maximum bubble pressure method.

[0084]

[0103] More preferably, the surfactant is selected to produce a disinfectant working solution having a dynamic surface tension of less than about 42.5 mN / m at a surface lifetime of 250 ms, less than about 41 mN / m at a surface lifetime of 500 ms, and less than about 40 mN / m at a surface lifetime of 5000 ms, at 25 - 25 °C, as measured by the maximum bubble pressure method.

[0085]

[0104] Examples of suitable surfactants that can be used in the compositions of the present invention include, but are not limited to, block copolymers of polyethylene oxide and polypropylene oxide, fatty alcohol alkoxylates, long-chain alkyl alkoxylates, N-alkyl pyrrolidones, branched short-chain perfluorosurfactants, branched short-chain polysiloxane-functionalized polyglycols, and combinations thereof.

[0086]

[0105] (Hydrotrope)

[0106] A hydrotrope is a compound that solubilizes a hydrophobic compound in an aqueous solution by means other than micellar solubilization. Typically, a hydrotrope consists of a hydrophilic part and a hydrophobic part (similar to a surfactant), but the hydrophobic part is generally too small to cause natural self-association.

[0087]

[0107] The hydrotrope can be used in the disinfectant composition of the present invention to enable solubilization of components that are insoluble in other respects, such as a low-foaming nonionic surfactant.

[0088]

[0108] Suitable hydrotropes include, but are not limited to, potassium xylene sulfonate, potassium naphthalene sulfonate, potassium cumene sulfonate, potassium cresyl phosphate, potassium octyliminodipropionate, sodium xylene sulfonate, sodium naphthalene sulfonate, sodium cumene sulfonate, sodium cresyl phosphate, sodium octyliminodipropionate, pentyl glucoside, hexyl glucoside, octyl glucoside, isooctyl glucoside, and mixtures thereof.

[0089]

[0109] In a preferred embodiment, the hydrotrope is present in an amount of about 0.1% to about 15% w / w, more preferably about 0.5% to about 10% w / w, of part B of the two-part disinfectant concentrate.

[0090]

[0110] In a second preferred embodiment, the hydrotrope is present in an amount of about 0.1% to about 15% w / w, more preferably about 0.5% to about 10% w / w, of the equilibrium peracetic acid concentrate of the single-part disinfectant concentrate.

[0091]

[0111] (pH adjuster)

[0112] The disinfectant working solution and disinfectant concentrate of the present invention may also contain a pH adjuster to control the pH of the final disinfectant composition. These pH adjusters are selected from the group consisting of alkali metal hydroxides, alkali metal carbonates, and alkali metal salts of polyvalent acids, such as alkali metal salts of citric acid, boric acid, phosphoric acid, oxalic acid, maleic acid, and fumaric acid.

[0092]

[0113] The pH adjuster may be used to control the pH of part B of the disinfectant concentrate itself, enabling the use of surfactants that may be unstable to acids or bases. The pH of part B of the disinfectant concentrate is preferably in the range of about 6.0 to about 13, more preferably about 7.0 to about 13.

[0093]

[0114] The pH adjuster in part B can achieve the preferred pH of the disinfectant working solution and allows for the presence of acidic species that may be present in the starting part A (PAA) solution. The pH of the disinfectant working solution of the present invention is preferably in the range of about 2.0 to about 8, more preferably about 3.0 to about 6.0.

[0094]

[0115] [Two - part disinfectant concentrate]

[0116] In a two - part disinfectant concentrate, the disinfectant concentrate is supplied as two parts (referred to as "part A" and "part B" for clarity), typically as two solutions. Part A typically contains an aqueous equilibrium solution of PAA, hydrogen peroxide, and acetic acid. Part A may also contain small amounts of other components, such as stabilizers or strong acids. Stabilizers can be selected from the group consisting of, but not limited to, aminotri(methylenephosphonic acid), 1 - hydroxylideneethylidene - 1,1 - diphosphonic acid, quinolin - 8 - ol, 2,6 - pyridinedicarboxylic (dipicolinic) acid, diethoxysuccinate aspartate, quinoline - 2 - carboxylic acid, citric acid, isocitric acid, aconitic acid, propane - 1,2,3 - tricarboxylic acid, and mixtures thereof.

[0095]

[0117] Strong acids may be used as catalysts for forming PAA. The strong acids that can be used in the present invention can be selected from, but are not limited to, sulfuric acid, nitric acid, methanesulfonic acid, trifluoromethanesulfonic acid, and mixtures thereof.

[0096]

[0118] Also, the use of commercially available PAA equilibrium solutions is also anticipated. It has been found that commercial grade PAA contains stabilizers and optionally strong acids.

[0097]

[0119] In a preferred embodiment, part B of the disinfectant concentrate contains from about 0.05% w / w to about 15% w / w surfactant. In a more preferred embodiment, the single-part disinfectant concentrate contains from about 0.1% w / w to about 10% w / w surfactant. In a highly preferred embodiment, the disinfectant concentrate contains from about 1% to about 9% w / w surfactant.

[0098]

[0120] Part B of the disinfectant concentrate may contain other components such as corrosion inhibitors, pH adjusters, surfactants, colorants, and indicators. Part B may also contain hydrotropes that assist in solubilizing the various components of the solution.

[0099]

[0121] In a preferred embodiment, the disinfectant working solution of the present invention is produced by combining a portion of the part A and part B solutions with water to produce an aqueous disinfectant working solution. Preferably, the ratio of part A to the part B solution is from about 1:10 to about 10:1 by volume weight. More preferably, the ratio of part A to the part B solution is from about 1:5 to about 5:1 by volume weight. Most preferably, the ratio of part A to the part B solution is about 1:1 by volume weight.

[0100]

[0122] The resulting diluted or disinfectant working solution preferably contains from about 0.01% w / v to about 1.0% w / v (100 ppm to 10,000 ppm) of PAA, more preferably from about 0.02% w / v to about 0.5% w / v (200 ppm to 5000 ppm) of PAA, of the disinfectant working solution.

[0101]

[0123] Those skilled in the art obtain the knowledge that the concentration of the active ingredient of the disinfectant (in this case, PAA) is determined by a combination of factors such as the contact time of disinfection, the disinfection temperature suitable for microbiological testing, and the desired microbiological performance (e.g., high-level disinfection or sterilization).

[0102]

[0124] Other factors such as the compatibility of the material can also determine the PAA concentration. For example, the corrosiveness of the disinfectant working solution can be reduced by decreasing the concentration of PAA while increasing the contact time and / or the disinfection temperature. Similarly, when the equipment to be disinfected is relatively resistant to corrosion by the disinfectant, more rapid disinfection can be achieved using a higher concentration and / or a higher temperature and a shorter disinfection contact time.

[0103]

[0125] Single-part disinfectant concentrates can provide a certain degree of convenience to the end user, and two-part disinfectant concentrates provide production flexibility in that the components of part B are not required for long-term stability against oxidation by peracids, etc.

[0104]

[0126] [Single-part disinfectant concentrate]

[0127] In a single-part disinfectant concentrate, all components are preferably supplied as a single concentrate, which is then preferably diluted with water before use to obtain a disinfectant working solution. In another embodiment, the single-part disinfectant can be used without dilution (i.e., a ready-to-use solution). The resulting disinfectant working solution preferably contains from about 0.01% w / v to about 1.0% w / v (100 ppm to 10,000 ppm) of PAA, more preferably from about 0.02% w / v to about 0.5% w / v (200 ppm to 5000 ppm) of PAA, of the disinfectant working solution.

[0105]

[0128] Those skilled in the art obtain the knowledge that the concentration of the active ingredient of the disinfectant (in this case, PAA) is determined by a combination of factors such as the contact time of disinfection, the disinfection temperature suitable for microbiological testing, and the desired microbiological performance (e.g., high-level disinfection or sterilization).

[0106]

[0129] Other factors such as material compatibility can also determine the PAA concentration. For example, the corrosiveness of the disinfectant working solution can be reduced by decreasing the concentration of PAA while increasing the contact time and / or the disinfection temperature. Similarly, when the equipment to be disinfected is relatively resistant to corrosion by the disinfectant, more rapid disinfection can be achieved using a higher concentration and / or a higher temperature and a shorter disinfection contact time.

[0107]

[0130] The single-part disinfectant concentrate contains PAA, hydrogen peroxide, and acetic acid. The single-part disinfectant concentrate also contains at least one surfactant, and optionally a corrosion inhibitor, a hydrotrope and / or a pH buffer, and a stabilizer.

[0108]

[0131] In a preferred embodiment, the single-part disinfectant concentrate contains about 0.1% w / w to 20% w / w peracetic acid.

[0109]

[0132] In a more preferred embodiment, the single-part disinfectant concentrate contains about 1% w / w to 15% w / w peracetic acid.

[0110]

[0133] In a highly preferred embodiment, the single-part disinfectant concentrate contains about 4% w / w to 6% w / w peracetic acid.

[0111]

[0134] The stabilizer can be selected from the group consisting of, but not limited to, aminotri(methylenephosphonic acid), 1-hydroxylethylidene-1,1-diphosphonic acid, quinolin-8-ol, 2,6-pyridinedicarboxylic (dipicolinic) acid, diethoxysuccinate alparagine acid, quinoline-2-carboxylic acid, citric acid, isocitric acid, aconitic acid, and propane-1,2,3-tricarboxylic acid.

[0112]

[0135] Typically, the stabilizer is present at a concentration of about 0.1% w / w to about 1% w / w of the single-part disinfectant concentrate.

[0113]

[0136] The single-part disinfectant concentrate may optionally contain a strong acid selected from, but not limited to, sulfuric acid, nitric acid, methanesulfonic acid, trifluoromethanesulfonic acid, and mixtures thereof. As can be appreciated by those skilled in the art, a strong acid can be added to act as a catalyst during the formation of the PAA solution.

[0114]

[0137] Typically, the acid is present at a concentration of about 0.1% w / w to about 1% w / w of the single-part disinfectant concentrate.

[0115]

[0138] The single-part disinfectant concentrate can be produced by mixing hydrogen peroxide, acetic acid, water, a stabilizer, at least one surfactant, and optionally a corrosion inhibitor, hydrotrope, and / or pH buffer.

[0116]

[0139] The reaction to produce PAA may be uncatalyzed, whereby PAA forms over several days, or it may be catalyzed by adding a strong acid selected from, but not limited to, sulfuric acid, nitric acid, methanesulfonic acid, trifluoromethanesulfonic acid, and mixtures thereof. Typically, the acid is present at a concentration of about 0.1% w / w to about 1% w / w of the single-part disinfectant concentrate.

[0117]

[0140] In a second embodiment, the single-part disinfectant concentrate is produced by adding at least one surfactant, and optionally a corrosion inhibitor, hydrotrope, and / or pH buffer, to a pre-formed PAA solution. This pre-formed solution may be commercially available. Commercial grade PAA is recognized to contain a stabilizer and optionally a strong acid.

[0118]

[0141] In a preferred embodiment, the single-part disinfectant concentrate contains about 0.05% w / w to about 15% w / w of a surfactant. In a more preferred embodiment, the single-part disinfectant concentrate contains about 0.1% w / w to about 10% w / w of a surfactant. In a highly preferred embodiment, the disinfectant concentrate contains about 1% w / w to about 9% w / w of a surfactant.

[0119]

[0142] Those skilled in the art will understand that all components in the single-part disinfectant concentrate should be stable against oxidation by peroxide species.

[0120]

[0143] [Disinfectant working solution]

[0144] As used herein, a disinfectant working solution is defined as a disinfectant formed by diluting a disinfectant concentrate, and is a disinfectant solution used to disinfect reusable heat-labile medical devices such as flexible endoscopes.

[0121]

[0145] In the case of a single-part disinfectant concentrate, the disinfectant working solution is produced by diluting the single-part disinfectant concentrate.

[0122]

[0146] In the case of a two-part disinfectant concentrate, the disinfectant working solution is formed by diluting a mixture of two parts (Part A and Part B). Typically, the disinfectant working solution is formed by adding Part A and Part B to a required amount of water and avoiding any harmful reactions that would occur from mixing the undiluted concentrates together.

[0123]

[0147] In a preferred embodiment, the disinfectant working solution of the present invention is produced by combining a portion of the Part A and Part B solutions with water to produce an aqueous disinfectant working solution. Preferably, the ratio of Part A to the Part B solution is from about 1:10 to about 10:1 by volume weight. More preferably, the ratio of Part A to the Part B solution is from about 1:5 to about 5:1 by volume weight. Most preferably, the ratio of Part A to the Part B solution is about 1:1 by volume weight.

[0124]

[0148] The concentration of PAA in the disinfectant working solution is preferably from 0.01% w / v to about 1.0% w / v (100 ppm to 10,000 ppm) of PAA in the disinfectant working solution, more preferably from about 0.02% w / v to about 0.5% w / v (200 ppm to 5000 ppm) of PAA.

[0125]

[0149] It is recognized that in many cases, more concentrated disinfectants are used for sterilization rather than for high-level disinfection.

[0126]

[0150] When used for high-level disinfection, the concentration of PAA in the disinfectant working solution is preferably 0.01% w / v to about 0.5% w / v (100 ppm to 5,000 ppm) of PAA, more preferably about 0.02% w / v to about 0.25% w / v (200 ppm to 2,500 ppm) of PAA, based on the disinfectant working solution.

[0127]

[0151] When used as a sterilant, the concentration of PAA in the disinfectant working solution is preferably 0.02% w / v to about 1.0% w / v (200 ppm to 10,000 ppm) of PAA, more preferably about 0.04% w / v to about 0.5% w / v (400 ppm to 5,000 ppm) of PAA, based on the disinfectant working solution.

[0128]

[0152] As recognized by those skilled in the art, the minimum concentration of PAA is determined by microbiological testing according to national regulations and is also determined by the temperature of disinfection and / or sterilization and the contact time for disinfection and / or sterilization.

[0129]

[0153] For example, the two-part disinfectant Rapicide PA (Medivators Inc., Minneapolis, MN, USA) has a recommended minimum concentration of 850 ppm of PAA for high-level disinfection with a contact time of 5 minutes at 30°C and a recommended minimum concentration of 1,700 ppm of PAA for sterilization with a contact time of 10 minutes at 40°C. These concentrations are achieved by diluting the Rapicide A and B solutions to 1.7 - 1.9% v / v for high-level disinfection and 3.4 - 3.8% v / v for sterilization. In this case, equal volumes of the part A and B solutions are used.

[0130]

[0154] The disinfectant working solution also contains at least one surfactant in an amount of about 0.05% w / v to about 0.5% w / v.

[0131]

[0155] Suitable surfactants for use in the disinfectant working solution of the present invention include ionic, non-ionic, zwitterionic and amphoteric surfactants, or mixtures thereof. Preferably, the surfactant or surfactant mixture has low foaming properties and also acts as a wetting agent.

[0132]

[0156] Examples of suitable surfactants that can be used in the composition of the present invention include, but are not limited to, block copolymers of polyethylene oxide and polypropylene oxide, fatty alcohol alkoxylates, long-chain alkyl alkoxylates, N-alkyl pyrrolidones, branched short-chain perfluorinated surfactants, branched short-chain polysiloxane-functionalized polyglycols, and combinations thereof.

[0133]

[0157] Optionally, it also contains about 0.01 to about 0.1% of at least one corrosion inhibitor and up to 0.2% of a hydrotrope.

[0134]

[0158] Suitable corrosion inhibitors may include, but are not limited to, benzotriazole, alkali metal phosphates, alkali metal nitrates, alkali metal nitrites, 2-phosphonobutane-1,2,4-tricarboxylate, metal molybdates, and combinations thereof.

[0135]

[0159] Suitable hydrotropes include, but are not limited to, potassium xylene sulfonate, potassium naphthalene sulfonate, potassium cumene sulfonate, potassium cresyl phosphate, potassium octyliminodipropionate, sodium xylene sulfonate, sodium naphthalene sulfonate, sodium cumene sulfonate, sodium cresyl phosphate, sodium octyliminodipropionate, pentyl glucoside, hexyl glucoside, octyl glucoside, isooctyl glucoside, and mixtures thereof.

[0136]

[0160] Other optional components in the disinfectant working solution can include pH adjusters, indicators, colorants, and fragrances.

[0137]

[0161] [Method Used]

[0162] [Example 1: Determination of Hydrogen Peroxide and PAA]

[0163] The hydrogen peroxide and PAA contents of the PAA solution were determined using two - step redox titration with a Mettler Toledo T70 automatic titrator. The automatic titrator was equipped with two burettes and a drive unit, a platinum - loop redox sensor, and a peristaltic pump for dispensing auxiliary solutions. One burette was filled with 0.02 M potassium permanganate solution and the second was filled with 0.1 M sodium thiosulfate solution. Both titrants were standardized before use.

[0138]

[0164] A sample of known weight was placed in a titration beaker together with 20 ml of 0.5 M sulfuric acid solution. The beaker was placed on the automatic titrator and hydrogen peroxide was determined by titration against the potassium permanganate solution. After identification of the end - point, 10 ml of 10% potassium iodide solution was added via the peristaltic pump (under the control of the T70 automatic titrator), and then the free iodine was titrated using the sodium thiosulfate solution. Then, taking into account the excess potassium permanganate added after the end - point, the concentrations of hydrogen peroxide and PAA were calculated by the automatic titrator.

[0139]

[0165] [Example 2: Determination of Acetic Acid]

[0166] The acetic acid content of the PAA solution was determined using acid - base titration with a single burette filled with 0.1 M sodium hydroxide solution and a Mettler Toledo T70 automatic titrator equipped with a pH sensor.

[0140]

[0167] A PAA solution of known weight was placed in a titration beaker and about 30 ml of deionized water was added. Then the beaker was placed on the automatic titrator and the sample was titrated against 0.1 M sodium hydroxide solution.

[0141]

[0168] [Example 3: Measurement of Dynamic Surface Tension]

[0169] The dynamic surface tensions of various disinfectant solutions were determined over a range of surface lifetimes (typically 14 ms to 5000 ms) using a Kruss BP50 tensiometer (Kruss GMBH, Hamburg, Germany). A new capillary tip was fixed to the BP50 for each set of measurements, and the instrument was re-calibrated with HPLC water each time the capillary tip was changed.

[0142]

[0170] Data from the BP50 was acquired using the software package Laboratory Desktop version 3.2.2.3064 supplied by Kruss.

[0143]

[0171] The surface tension at a specific surface lifetime was calculated by interpolation of the data points on either side of that lifetime. For example, the surface tension at 500 ms can be calculated from the surface tension values of 29.1 mN / m and 28.0 mN / m at surface lifetimes of 440 ms and 555 ms respectively, by assuming linearity between these two points and determining the gradient and intercept of the straight line between these two points. In the above example, the surface tension at 500 ms can be calculated as 28.5 mN / m.

[0144]

[0172] [Prior Art Examples]

[0173] Figure 3 shows a comparison of the dynamic surface tensions over a range of surface lifetimes between some prior art examples of PAA-based disinfectants and an exemplary embodiment of the disinfectant working solution of the present invention. As can be clearly seen, all exemplary embodiments reach a surface tension of less than about 42.5 mN / m more characteristically quickly than the prior art examples and reach a surface tension of less than 40 mN / m by 5000 ms.

[0145]

[0174] Examples 4 to 6 represent commercially available PAA-based high-level disinfectants intended for use in automatic endoscope reprocessing devices.

[0146]

[0175] [Example 4]

[0176] 1.9 ml of a 5% w / w PAA solution supplied by Proxy P (Whiteley Corporation, Tomago, NSW, Australia) was pipetted into a 100 ml volumetric flask containing approximately 80 ml of tap water. Then 1.9 ml of Proxy A (corrosion inhibitor concentrate) was added by pipette, and the solution was made up to volume with additional tap water to form a disinfectant working solution.

[0147]

[0177] Next, the surface tension of the resulting disinfectant working solution was measured over the range of surface lifetimes (14 ms to 5000 ms) according to the procedure outlined in Example 3. As can be seen in Figure 4 and Table 2, there is no substantial decrease in the surface tension of the disinfectant (the surface tension of pure water is 72 mN / m, and there is no significant variation in surface tension with surface lifetime).

Table 2

[0148]

[0178] [Example 5]

[0179] 1.9 ml of Soluscope P (a 5% w / w PAA solution supplied by Soluscope SAS, France) was pipetted into a 100 ml volumetric flask containing approximately 80 ml of tap water. Then 1.9 ml of Soluscope A (corrosion inhibitor concentrate) was added by pipette, and the solution was made up to volume.

[0149]

[0180] Next, the surface tension of the resulting disinfectant working solution was measured over the range of surface lifetimes (14 ms to 5000 ms) as described in Example 3. As can be seen in Figure 4 and Table 3, again, there is no substantial decrease in the surface tension of the disinfectant compared to the surface tension of water (i.e., 72 mN / m).

Table 3

[0150]

[0181] [Example 6]

[0182] 1.9 ml of Rapicide PA Part A (a 5% w / w PAA solution supplied by Medivators Inc., Minneapolis, MN, USA) was pipetted into a 100 ml volumetric flask containing approximately 80 ml of tap water. Then 1.9 ml of Rapicide PA Part B (corrosion inhibitor concentrate) was added by pipette and the solution was made up to the mark with additional tap water.

[0151]

[0183] The dynamic surface tension of the resulting disinfectant working solution was measured over the range of 14 ms to 5000 ms. As can be seen in Figure 4 and Table 4, even with a long surface lifetime (i.e., over 5000 ms), there was an initial sharp decrease in surface tension to about 52 mN / m while maintaining a surface tension above 50 mN / m.

Table 4

[0152]

[0184] [Example 7]

[0185] In this example, a single-part disinfectant concentrate described in WO2016100818 was prepared. A 50% solution of hydrogen peroxide (560.02 g) was added to 250 ml of HPLC grade water (Sigma Aldrich), followed by the addition of 160.00 g of glacial acetic acid, 10.00 g of Dequest 2010 (IMCD, Mulgrave, VIC, Australia) and 20 g of Pluronic 10R5 (Sigma Aldrich, Castle Hill, NSW, Australia). The mixture was then left for at least two weeks to form PAA.

[0153]

[0186] After two weeks, the hydrogen peroxide and PAA contents were determined using the method of Example 1 and acetic acid was determined using the method of Example 2. The composition of the resulting disinfectant concentrate is shown in Table 5.

Table 5

[0154]

[0187] Next, 2 ml of this preparation was pipetted into a 100-ml volumetric flask and made up to the mark with tap water. Then, the dynamic surface tension of the obtained disinfectant working solution was measured according to the method of Example 3. [Table 6]

[0155]

[0188] As can be seen in FIG. 4 and Table 6, despite a relatively rapid initial decrease in surface tension to a value of 54.5 with a surface lifetime of 500 ms, the surface tension effectively maintains a steady state with only a slight difference in surface tension between 500 and 5000 ms.

[0156]

[0189] [Example 8]

[0190] The following examples represent prior art examples described in U.S. Patent No. 6,168,808. Four preparations were prepared according to Table 7. [Table 7]

[0157]

[0191] The PAA solution used was an equilibrium solution supplied by Solvay Interox Pty Ltd. (Banksmeadow, NSW, Australia). This PAA solution contains 5% PAA, 27% hydrogen peroxide, and 7.5% acetic acid.

[0158]

[0192] In these examples, Genapol EP2564 (Clariant Pty Ltd., Lara, VIC, Australia) was used. This surfactant was previously known under the trade name Genapol 2908D. Ammonyx LO is a coco dimethylamine oxide supplied by Ixom Operations Pty Ltd., East Melbourne, (VIC, Australia).

[0159]

[0193] 2 ml of each solution was pipetted into a 100-ml volumetric flask and diluted to the mark with tap water.

[0160]

[0194] The dynamic surface tension of each dilution solution was evaluated according to the method of Example 3. The plots of the dynamic surface tension for these examples are shown in Figure 5, and the surface tensions at 250 ms, 500 ms, and 5000 ms are listed in Table 8. As can be seen, the decrease in surface tension of each formulation up to the first 500 ms is slow. Even up to 5000 ms, the surface tension of each formulation is still over 45 mN / m.

Table 8

[0161]

[0195] [Example 9]

[0196] The following examples were carried out from European Patent No. 0971584. Since each example described in European Patent No. 0971584 was prepared from PAA solutions with different compositions, various PAA solutions were prepared as shown below.

[0162]

[0197] (Preparation of PAA samples)

[0198] A series of PAA solutions were prepared by mixing deionized water, 50% hydrogen peroxide solution, and glacial acetic acid. 1-Hydroxyethylidene-1,1-diphosphonic acid (HEDP) was added to each formulation as a stabilizer (see Table 9 for the amounts).

Table 9

[0163]

[0199] The solution was allowed to stand at room temperature for 2 - 3 weeks to reach equilibrium in the system. Then, each sample was analyzed for PAA and hydrogen peroxide using the method described in Example 1. The acetic acid content of the sample was determined using the method described in Example 2.

[0164]

[0200] The composition of each PAA sample is shown in Table 10.

Table 10

[0165]

[0201] Subsequently, using the PAA solution, Compositions 1 to 5 shown in Table A of European Patent No. 0971584 were reproduced (see Table 11). [Table 11] Note: Genapol EP2564 is currently supplied by Clariant (Australia) Pty Ltd. (Lara, VIC, Australia) and was previously known as Genapol 2908D. Genapol EP2584 is currently supplied by Clariant (Australia) Pty Ltd. (Lara, VIC, Australia) and was previously known as Genapol 2909.

[0166]

[0202] According to European Patent No. 0971584, Sample 9A (1.25 ml) was diluted to 100 ml with tap water to obtain a 1-part 80-fold disinfectant working solution. Similarly, according to European Patent No. 0971584, 2.5 ml of Samples 9B to 9E were diluted to 100 ml with tap water to obtain a 1-part 40-fold disinfectant working solution.

[0167]

[0203] Subsequently, the dynamic surface tension of the obtained diluted solution was measured as described in Example 3.

[0168]

[0204] As can be seen in FIG. 6 and Table 12, the surface tensions of the various disinfectant working solutions 9A to 9E reach low values (less than 45 mN / m), but this is only achieved with a long surface lifetime (more than 15000 ms). [Table 12]

[0169]

[0205] Interestingly, as shown in Table 1, it should be noted that the surface tension measured and observed using the maximum bubble pressure method is significantly higher than the surface tension reported in European Patent No. 0971584 for the same formulation when measured by the static method (Wilhelmy plate method).

[0170]

[0206] [Examples of the Invention]

[0207] The following examples represent non-limiting embodiments of the present invention. These examples are representative examples of two-part disinfectants and are intended to be mixed with a PAA solution to form a practical disinfectant.

[0171]

[0208] [Example 10]

[0209] A composition (100 ml) shown in Table 13 was prepared.

[0172]

[0210] Triton H66 (a solution of potassium cresyl phosphate) was obtained from Dow Chemicals. Pluronic PE6400 (a triblock copolymer of polyethylene oxide and polypropylene oxide) was obtained from BASF. Makon NF12 is a low-foaming C10 - C12 alcohol alkoxylate supplied by Stepan Company (Northfield, IL, USA), and Surfadone LP100 is a low-foaming nonionic high-speed wetting agent containing N-octyl-2-pyrrolidone without a critical micelle concentration, supplied by Ashland Global Holdings (Covington, KY, USA). The formulation has a pH of 11.93.

Table 13

[0173]

[0211] 2 mL of the formulation of Example 10 was pipetted into a 100 mL volumetric flask containing approximately 80 mL of tap water. To this, 2 mL of Rapicide PA Part A, a 5% w / w PAA solution obtained from Cantel Australia (Heatherton, VIC, Australia), was added. The resulting solution was then made up to volume with additional tap water to produce a disinfectant working solution. The pH of the dilution solution was 4.04.

[0174]

[0212] The disinfectant working solution contained 0.025% corrosion inhibitors (benzotriazole and sodium molybdate), 0.14% surfactants (Pluronic PE6400, Makon NF12, and Surfadone LP100), 0.05% hydrotrope (Triton H66), together with 2% Proxitane (i.e., 0.1% PAA).

[0175]

[0213] The dynamic surface tension of the disinfectant working solution was then measured as described in Example 3. Figure 7 shows a plot of surface tension (mN / m) versus surface lifetime (milliseconds), and Table 14 shows the surface tensions for selected surface lifetimes.

Table 14

[0176]

[0214] [Example 11]

[0215] The following example demonstrates the use of a branched short-chain nonionic surfactant commonly referred to as a “super-spreader”. Due to the acid-labile nature of the silicone-based hydrophobic moiety, the concentrate was formulated to obtain a pH-neutral solution.

[0177]

[0216] The following formulation (100 mL) was prepared.

Table 15

[0178]

[0217] FC-41 is a low-foaming isooctyl glucoside obtained from Interchem Pty Ltd. (Abbotsford, VIC, Australia). Orthowet H-408 obtained from Ortho Chemicals (Kensington Victoria, Australia) is a solution of 3-(polyoxyethylene)propyl heptamethyltrisiloxane. This surfactant is an example of a class of silicone-based surfactants known as super-spreaders due to its ability to impart rapid wetting and low surface tension to aqueous solutions. Acticide B20 is a glycol-based benzisothiazolinone preservative solution manufactured by Thor Specialties Pty Limited (Wetherill Park, NSW, Australia).

[0179]

[0218] The pH of the stock solution was set to 7.32 to prevent hydrolysis of Orthowet H-408 during storage.

[0180]

[0219] 2 ml of the formulation shown in Table 15 was pipetted into a 100 ml volumetric flask containing approximately 80 ml of tap water. To this, 2 ml of Proxitane (a 5% w / w solution of PAA) was added. The resulting solution was then made up to volume with additional tap water to produce a disinfectant working solution. The pH of the diluted solution was 2.98.

[0181]

[0220] Disinfectant working solutions using the 0.5%, 1.0% and 1.5% formulations of Table 15 (each containing 0.5%, 1.0% and 1.5% Proxitane) were similarly prepared. The concentrations of each functional ingredient (corrosion inhibitor, surfactant, hydrotrope and PAA) are shown in Table 16.

Table 16

[0182]

[0221] Next, the dynamic surface tension of the disinfectant working solution was measured as described in Example 3. Figure 7 shows a plot of surface tension (mN / m) versus surface lifetime (milliseconds) for the 2% solution, and Table 17 shows the surface tensions of the selected surface lifetimes for each concentration. [Table 17]

[0183]

[0222] Next, the dynamic surface tension of the disinfectant working solution was measured as described in Example 3, using a Kruss BP50 tensiometer. Figure 7 shows a plot of surface tension (mN / m) versus surface lifetime (milliseconds) for the 2% solution, and Table 16 shows the surface tensions of the selected surface lifetimes for each concentration.

[0184]

[0223] [Example 12]

[0224] In this example, the effects of the various components of Example 10 were investigated.

[0185]

[0225] A base solution was prepared containing 907.77 g of deionized water, 46.22 g of dipotassium hydrogen phosphate anhydrous, 30.98 g of a 48% w / w potassium hydroxide solution, and 10.36 g of benzotriazole.

[0186]

[0226] Next, using the base solution, various formulations of Table 18 were prepared. Where possible, formulations containing only one additional component selected from Triton H66, Pluronic PE6400, Surfadone LP100, and Makon NF12 were also prepared.

[0187]

[0227] In the case of Surfadone LP100 and Makon NF12, these surfactants were insoluble in the base formulation and were therefore solubilized using the hydrotrope, Triton H66 (see Formulations 12-D and 12-F). [Table 18]

[0188]

[0228] As described in Example 10, from each of these solutions, a dilution solution containing 2% v / v of various formulations together with 2% v / v of Rapicide PA Part A was prepared. According to Example 3, the surface tension of the various surface lives of each disinfectant working solution was measured.

[0189]

[0229] As can be seen in FIG. 8 and Table 19, the addition of Triton H66 to the base solution has only a very slight effect on the dynamic surface tension.

[0190]

[0230] The addition of Pluronic H66 (see Formulation 12-C) results in a sharp drop in surface tension to 45.4 mN / m with a surface life of 500 ms, and subsequently this value is substantially maintained, giving a surface tension of 43.9 mN / m at 5000 ms.

[0191]

[0231] The addition of Surfadone LP100 appears to act synergistically with these various formulations, resulting in a sharp drop in surface tension to a value substantially lower than that observed, for example, with Pluronic PE6400 alone. For example, the addition of Surfadone LP100 to Formulation 12-C reduces the surface tension from 46 mN / m to 38 mN / m with a surface life of 250 ms.

Table 19

[0192]

[0232] [Example 13]

[0233] In these examples, while using Triton H66 as a hydrotrope, the fast wetting surfactant Ecosurf LFE-635, a branched alcohol alkoxylate (Dow Chemicals Co., Ltd.), is used to bring about rapid wetting.

[0193]

[0234] As shown in Table 20, various concentrations of Ecosurf LFE-635 in the range of 2.5% w / v to 5% w / v were prepared.

Table 20

[0194]

[0235] Next, 2 ml of the formulation was pipetted into a 100 ml volumetric flask containing approximately 80 ml of tap water. Then 2 ml of Proxitane was added and the solution was made up to volume with additional tap water to form the disinfectant working solution. Table 21 shows the functional components of the disinfectant working solution.

Table 21

[0195]

[0236] Next, the dynamic surface tension of the disinfectant working solution was measured as described in Example 3.

[0196]

[0237] Figure 9 shows a plot of surface tension (mN / m) versus surface lifetime (milliseconds), and Table 22 shows the surface tension for selected surface lifetimes. As can be seen, these formulations result in a sharp drop in surface tension with a very short surface lifetime.

Table 22

[0197]

[0238] [Single-part disinfectant]

[0239] The following embodiments of the invention demonstrate a single-part formulation comprising a single solution based on a 5% solution of PAA. The PAA solution used was Proxitane.

[0198]

[0240] [Example 14]

[0241] The following example of a single-part disinfectant is based on the use of Bayhibit AM as a corrosion inhibitor and Pluronic PE6400 as a solubilizing surfactant. A branched short-chain anionic perfluorosurfactant (Tivida FL2200, Merck Pty Ltd., Bayswater, VIC, Australia) was used as a high-speed wetting agent. A series of formulations shown in Table 23 were prepared. Each formulation was observed to be clear and colorless with no apparent haze.

Table 23

[0199]

[0242] 2 mL of each formulation was pipetted into a 100 mL volumetric flask containing approximately 80 mL of tap water. The solution was then made up to volume with additional tap water to form the disinfectant working solution. The approximate functional composition of the disinfectant working solution is shown in Table 24.

Table 24

[0200]

[0243] The dynamic surface tension of the disinfectant working solution was then measured as described in Example 3.

[0201]

[0244] Figure 10 shows a plot of surface tension (mN / m) versus surface lifetime (milliseconds), and Table 25 shows the surface tensions for selected surface lifetimes. As can be seen, these formulations result in a sharp drop in surface tension with a very short surface lifetime.

Table 25

[0202]

[0245] [Example 15]

[0246] The following example of a single-part disinfectant concentrate is based on the use of Bayhibit AM as a corrosion inhibitor, together with Ecosurf LFE-635 as a fast wetting surfactant.

[0203]

[0247] Formulations shown in Table 26 were prepared using either Triton H66 or Pluronic PE6400 as solubilizers.

Table 26

[0204]

[0248] 2 mL of each formulation was pipetted into a 100 mL volumetric flask containing approximately 80 mL of tap water. The solution was then made up to volume with additional tap water to form the disinfectant working solution. The approximate functional composition of the disinfectant working solution is shown in Table 27. [Table 27]

[0205]

[0249] The dynamic surface tension of the disinfectant working solution was then measured as described in Example 3.

[0206]

[0250] Figure 11 shows a plot of surface tension (mN / m) against surface lifetime (milliseconds), and Table 28 shows the surface tensions for selected surface lifetimes. Again, these formulations result in a sharp drop in surface tension with a very short surface lifetime. [Table 28]

[0207]

[0251] Of note here is that the formulation containing only Proxitane and Pluronic PE6400 (Example 15C) shows an initial sharp drop in surface tension but only a slight decrease from a value of 43.7 mN / m at 500 ms to 42.4 mN / m at 5000 ms. The addition of the branched alkyl alkoxylate Ecosurf LFE-635 demonstrates a significant improvement in the decrease of surface tension, particularly when present in the formulation concentrate at levels higher than 1.85% w / w. As can be seen in Table 28, all formulations containing more than 1.85% w / w of Ecosurf FFE-635 showed surface tensions below 40 mN / m with surface lifetimes exceeding 250 ms.

[0208]

[0252] [Example 17: Microbiological effectiveness]

[0253] The following disinfectant working solutions were prepared as follows:

[0254] (Disinfectant 1 for testing)

[0255] 2 mL of Example 10 was pipetted into a 100 mL volumetric flask containing approximately 80 mL of artificial hard water (as 340 mg / L CaCO3) together with 2 mL of 5% PAA solution (Rapicide PA part A). The solution was made up to the mark with additional hard water. The resulting disinfectant working solution was then titrated to determine its PAA content and then further diluted with hard water to obtain a final PAA content of 857 ppm PAA and 3901 ppm hydrogen peroxide.

[0256] (Test disinfectant 2 (control formulation))

[0257] 2 mL of Rapicide PA part B was pipetted into a 100 mL volumetric flask containing approximately 80 mL of artificial hard water (as 340 mg / L CaCO3) together with 2 mL of 5% PAA solution (Rapicide PA part A). The solution was made up to the mark with additional hard water. The resulting disinfectant working solution was then titrated to determine its PAA content and then further diluted with hard water to obtain a final PAA content of 857 ppm PAA and 3929 ppm hydrogen peroxide.

[0209]

[0258] Both disinfectant working solutions were then evaluated for sporicidal efficacy in a time - kill test using a suspension of Bacillus subtilis spores (ATCC 19659) containing 1.8×108 CFU / mL with 5% horse serum added as organic matter soil.

[0210]

[0259] The test was carried out at 40 °C using various contact time ranges (5 s, 60 s, 120 s, 180 s and 240 s) with five replicates at each time point. After the required contact time, the disinfectant was neutralized and the surviving spores were counted.

[0211]

[0260] As can be seen in Table 29, Test Solution 1 prepared using the formulation of Example 10 demonstrated a 6 log 10 reduction.

Table 29

[0212]

[0261] [Example 16: Microbiological effectiveness: Spore carrier test]

[0262] In this test, a screening carrier test based on the AOAC sporicidal activity test was conducted, using four carriers for each of two concentrations of the test substance.

[0213]

[0263] (Disinfectant for test 1)

[0264] 2 ml of the formulation of Example 10 was pipetted into a 100-ml volumetric flask containing approximately 80 ml of artificial hard water (as 340 mg / L CaCO3), together with 2 ml of a 5% PAA solution (Rapicide PA part A). The solution was made up to the mark with additional hard water. The resulting disinfectant working solution was then titrated to determine its PAA content, and then further diluted with hard water to obtain a final PAA content of 856 ppm and 3840 ppm of hydrogen peroxide (HP).

[0214]

[0265] Four porcelain penicillin cylinders inoculated with Bacillus subtilis spores under contaminated conditions (5% horse serum) were then treated with the disinfectant working solution at 40°C at various time points (60 seconds, 120 seconds, 180 seconds, and 240 seconds). The disinfectant was neutralized with 10 ml of T6 neutralizer, and the samples were incubated to assess growth / no growth and to determine any remaining viable spores.

[0215]

[0266] (Disinfectant for test 2 (control))

[0267] 2 ml of Rapicide PA part B was pipetted into a 100-ml volumetric flask containing approximately 80 ml of artificial hard water (as 340 mg / L CaCO3), together with 2 ml of a 5% PAA solution (Rapicide PA part A). The solution was made up to the mark with additional hard water. The resulting disinfectant working solution was then titrated to determine its PAA content, and then further diluted with hard water to obtain a final PAA content of 868 ppm and 4000 ppm of hydrogen peroxide.

[0216]

[0268] Next, four porcelain penicillin cylinders inoculated with Bacillus subtilis spores under contamination conditions (5% horse serum) were treated with the disinfectant solution at 40°C at various time points (60 seconds, 120 seconds, 180 seconds, and 240 seconds). The disinfectant was neutralized with 10 ml of T6 neutralizer, and the samples were incubated to assess growth / no growth and to determine any remaining viable spores.

[0217]

[0269] After incubation, the following results were obtained. As can be seen in Table 30, the test substance (Example 10) showed no growth at all time points, while the control samples (Example 6, Rapicide PA) showed no viable spores at 60 seconds and 120 seconds. Note that this PAA concentration was that used for high-level disinfection of Rapicide PA, while the temperature was that specified for sterilization by Rapicide PA (even though the sterilization time is typically 10 minutes).

Table 30

[0218]

[0270] [Example 17: Microbiological effectiveness: Spore carrier test (higher PAA concentration).]

[0271] In this test, again, a screening carrier test based on the AOAC sporicidal activity test was performed, using four carriers for each of the two concentrations of the test substance.

[0219]

[0272] (Disinfectant for test 1)

[0273] 2 ml of the formulation of Example 10 was pipetted into a 100 ml volumetric flask containing about 80 ml of artificial hard water (as 340 mg / L CaCO3) together with 2 ml of 5% PAA solution (Rapicide PA part A). The solution was made up to the mark with additional hard water. The resulting disinfectant working solution was then titrated to determine its PAA content and then further diluted with hard water to obtain a final PAA content of 1700 ppm PAA and 7821 ppm hydrogen peroxide.

[0220]

[0274] Next, four porcelain penicillin cylinders inoculated with Bacillus subtilis spores under contaminated conditions (5% horse serum) were treated with the disinfectant working solution at 40 °C at various time points (60 seconds, 120 seconds, 180 seconds, and 240 seconds). The disinfectant was neutralized with 10 ml of T6 neutralizer, and the samples were incubated to evaluate growth / no growth and to determine any remaining viable spores.

[0221]

[0275] (Test disinfectant 2 (control))

[0276] 2 ml of Rapicide PA part B was pipetted into a 100 ml volumetric flask containing 2 ml of 5% PAA solution (Rapicide PA part A) along with approximately 80 ml of artificial hard water (as 340 mg / L CaCO3). The solution was made up to the mark with additional hard water. The resulting disinfectant working solution was then titrated to determine its PAA content and then further diluted with hard water to obtain a final PAA content of 1706 ppm PAA and 8019 ppm hydrogen peroxide.

[0222]

[0277] Next, four porcelain penicillin cylinders inoculated with Bacillus subtilis spores under contaminated conditions (5% horse serum) were treated with the disinfectant working solution at 40 °C at various time points (60 seconds, 120 seconds, 180 seconds, and 240 seconds). The disinfectant was neutralized, and the samples were incubated to evaluate growth / no growth and to determine any remaining viable spores.

[0223]

[0278] After incubation, the following results were obtained. As can be seen in Table 31, the test substance (Example 10) showed no growth at all time points, while the control sample (Example 6, Rapicide PA) showed no viable spores at 60 seconds.

Table 31

Claims

1. a. Peracetic acid and b. At least one surfactant A disinfectant working solution for sterilizing or disinfecting medical devices, comprising an aqueous dilution of a disinfectant concentrate containing the same, which exhibits a dynamic surface tension of less than about 50 mN / m at a surface lifetime of 250 ms and less than about 46 mN / m at a surface lifetime of 500 ms when measured by the maximum bubble pressure method at 20 to 25°C.

2. The disinfectant working solution according to claim 1, which exhibits a dynamic surface tension of less than about 42.5 mN / m at a surface lifetime of 250 ms and less than about 41.0 mN / m at a surface lifetime of 500 ms when measured by the maximum bubble pressure method at 20 to 25°C.

3. The disinfectant working solution according to claim 2, which exhibits a dynamic surface tension of less than about 42.5 mN / m at a surface lifetime of 250 ms, less than about 41 mN / m at a surface lifetime of 500 ms, and less than about 40 mN / m at a surface lifetime of 5000 nm when measured by the maximum bubble pressure method at 20 to 25°C.

4. The disinfectant working solution according to any one of claims 1 to 3, wherein the concentration of the peracetic acid is from 0.01% w / v to about 1.0% w / v (about 100 ppm to about 10,000 ppm) of the disinfectant working solution.

5. The disinfectant working solution according to any one of claims 1 to 3, wherein the concentration of the peracetic acid is from about 0.02% w / v to about 0.5% w / v (about 200 ppm to about 5000 ppm) of the disinfectant working solution.

6. The disinfectant working solution according to claim 5, wherein the concentration of the surfactant is from about 0.05% w / v to about 0.5% w / v of the disinfectant working solution.

7. The disinfectant working solution according to any one of claims 1 to 3, wherein the disinfectant concentrate is provided as a single-part disinfectant concentrate.

8. The disinfectant working solution according to any one of claims 1 to 3, wherein the disinfectant concentrate is provided as a two-part disinfectant concentrate having a first part and a second part.

9. The disinfectant working solution according to claim 7, wherein the single-part disinfectant concentrate contains from about 0.1% w / w to about 20% w / w peracetic acid of the disinfectant concentrate.

10. The disinfectant working solution according to claim 9, wherein the single-part disinfectant concentrate contains from about 1% w / w to about 15% w / w peracetic acid of the disinfectant concentrate.

11. The disinfectant working solution according to claim 10, wherein the single-part disinfectant concentrate contains from about 4% w / w to about 6% w / w peracetic acid of the disinfectant concentrate.

12. The disinfectant working solution according to any one of claims 1 to 11, wherein the at least one surfactant is selected from the group consisting of ionic, non-ionic, zwitterionic and amphoteric surfactants, and mixtures thereof.

13. The disinfectant working solution according to claim 12, wherein the surfactant is selected from the group consisting of block copolymers of polyethylene oxide and polypropylene oxide, fatty alcohol alkoxylates, long-chain alkyl alkoxylates, N-alkyl pyrrolidones, branched short-chain perfluorinated surfactants, branched short-chain polysiloxane-functionalized polyglycols, and combinations thereof.

14. The disinfectant working solution according to claim 7, wherein the single-part disinfectant concentrate contains from about 0.05% w / w to about 15% w / w of the surfactant in the disinfectant concentrate.

15. The disinfectant working solution according to claim 14, wherein the single-part disinfectant concentrate contains from about 0.1% w / w to about 10% w / w of the surfactant in the disinfectant concentrate.

16. The disinfectant working solution according to claim 15, wherein the single-part disinfectant concentrate contains from about 1% to about 9% w / w of the surfactant in the disinfectant concentrate.

17. The disinfectant working solution according to claim 7, wherein the single-part disinfectant concentrate additionally contains a corrosion inhibitor and / or a hydrotrope.

18. The disinfectant working solution according to claim 17, wherein the corrosion inhibitor is selected from the group consisting of benzotriazole, alkali metal phosphates, alkali metal nitrates, alkali metal nitrites, 2-phosphonobutane-1,2,4-tricarboxylate, metal molybdates, and combinations thereof.

19. The disinfectant working solution according to claim 17 or claim 18, wherein the single-part disinfectant concentrate contains from about 0.1% w / v to about 2% w / v of the corrosion inhibitor in the disinfectant concentrate.

20. The disinfectant working solution according to claim 17, wherein the hydrotrope is selected from the group consisting of potassium xylene sulfonate, potassium naphthalene sulfonate, potassium cumene sulfonate, potassium cresyl phosphate, potassium octyliminodipropionate, sodium xylene sulfonate, sodium naphthalene sulfonate, sodium cumene sulfonate, sodium cresyl phosphate, sodium octyliminodipropionate, pentyl glucoside, hexyl glucoside, octyl glucoside, isooctyl glucoside, and mixtures thereof.

21. The disinfectant working solution according to claim 20, wherein the single-part disinfectant concentrate contains about 0.1% to about 15% w / w of the hydrotrope based on the disinfectant concentrate.

22. The disinfectant working solution according to claim 8, wherein the first part of the two-part disinfectant concentrate contains an equilibrium solution of peracetic acid, hydrogen peroxide, acetic acid, and water.

23. The disinfectant working solution according to claim 22, wherein the first part contains about 0.1% w / w to about 20% w / w of peracetic acid based on the first part.

24. The disinfectant working solution according to claim 23, wherein the first part contains about 1% w / w to about 15% w / w of peracetic acid based on the first part.

25. The disinfectant working solution according to claim 24, wherein the first part contains about 4% w / w to about 6% w / w of peracetic acid based on the first part.

26. The disinfectant working solution according to any one of claims 22 to 25, wherein the second part of the two-part disinfectant concentrate contains at least one surfactant.

27. The disinfectant working solution according to claim 26, wherein the surfactant is selected from the group consisting of ionic, non-ionic, zwitterionic, and amphoteric surfactants, and mixtures thereof.

28. The disinfectant working solution according to claim 27, wherein the surfactant is selected from the group consisting of block copolymers of polyethylene oxide and polypropylene oxide, fatty alcohol alkoxylates, long-chain alkyl alkoxylates, N-alkyl pyrrolidone, branched short-chain perfluorinated surfactants, branched short-chain polysiloxane-functionalized polyglycols, and combinations thereof.

29. The disinfectant working solution according to any one of claims 26 to 28, wherein the surfactant occupies about 0.05% w / w to about 15% w / w of the second part.

30. The disinfectant working solution according to claim 29, wherein the surfactant occupies from about 0.1% w / w to about 10% w / w of the second part.

31. The disinfectant working solution according to claim 30, wherein the surfactant occupies from about 1% w / w to about 9% w / w of the second part.

32. The disinfectant working solution according to claim 26, wherein the second part of the two-part disinfectant concentrate additionally contains a corrosion inhibitor and / or a hydrotrope.

33. The disinfectant working solution according to claim 32, wherein the corrosion inhibitor is selected from the group consisting of benzotriazole, alkali metal phosphates, alkali metal nitrates, alkali metal nitrites, 2-phosphonobutane-1,2,4-tricarboxylate, metal molybdates, and combinations thereof.

34. The disinfectant working solution according to claim 32 or 33, wherein the corrosion inhibitor is present at a concentration of from about 0.1% w / v to about 2% w / v of the two-part disinfectant concentrate.

35. The disinfectant working solution according to claim 32, wherein the hydrotrope is selected from the group consisting of potassium xylenesulfonate, potassium naphthalenesulfonate, potassium cumenesulfonate, potassium cresyl phosphate, potassium octyliminodipropionate, sodium xylenesulfonate, sodium naphthalenesulfonate, sodium cumenesulfonate, sodium cresyl phosphate, sodium octyliminodipropionate, pentyl glucoside, hexyl glucoside, octyl glucoside, isooctyl glucoside, and mixtures thereof.

36. The disinfectant working solution according to claim 35, wherein the hydrotrope is present in an amount of from about 0.1% to about 15% w / w of the second part of the two-part disinfectant concentrate.

37. A method for disinfecting or sterilizing a medical device, comprising the step of contacting the medical device with a disinfectant working solution comprising an aqueous dilution of a disinfectant concentrate comprising a. peracetic acid and b. at least one surfactant wherein the disinfectant working solution exhibits a dynamic surface tension of less than about 50 mN / m at a surface lifetime of 250 ms and less than about 46 mN / m at a surface lifetime of 500 ms when measured by the maximum bubble pressure method at 20 - 25°C.

38. A method for disinfecting or sterilizing a medical device, comprising the step of contacting the medical device with the disinfectant working solution according to any one of claims 1 to 36.

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