Cold sterilant with extended active life

Background of the Invention The present invention relates to the field of microbial decontamination. Applications have been found in this area, in particular, in connection with powder sterilant concentrates that react in water at room temperature to form microcidally active compositions. This concentrate is used in field medical Has an extended lifespan due to use), and is specifically described in this regard. It should be understood that the present invention also finds applications related to other antibacterial applications, including bactericidal compositions used at elevated temperatures, other bactericidal compositions with a selectable duration of activity, and the like. is there. The prior US Pat. No. 5,116,575 of the present inventors describes a powdered antibacterial composition. This composition is ideally suitable for use in an automated liquid sterilization system as set forth in US Pat. No. 4,892,706 or 5,217,698 referenced in the above literature. The antibacterial composition contains two components that react in the presence of water to form a strong oxidant. Preferably, acetylsalicylic acid reacts with perborate (eg, sodium perborate) to form peracetic acid. The powder component further contains corrosion resistant substances and buffers. Corrosive substances suppressed the corrosion of brass, copper, aluminum, steel, and other substances commonly found in medical, dental, and surgical instruments. The buffer controlled the chemical reaction and helped control the corrosion. In particular, preferred compositions were formulated for optimal efficiency at 50 ° C. and provided and retained peak peracetic acid concentrations for the duration of automated cycles on the order of 1/2 hour. The previous formulation was effective for these intended purposes, but reacted quickly in water at room temperature (about 25 ° C) and was antibacterial for long periods of time on the order of 8 hours. It is also necessary to produce a good solution. Such formulations must also control corrosion and buffer pH to the optimum range. A paper by Death and Coates entitled "Effects of pH on spore-killing and bactericidal activity of buffered mixtures of alcohol and sodium hypochlorite" in Journal of Clinical Pathology, Vol. 32, pp. 148-153 (1979) , About 7.6 ~ 8. When buffered to a pH of 1, it exhibits excellent bactericidal activity in the methanol / hypochlorite mixture and hypochlorite alone. Journal of Hygiene, Epidemiology, Microbiology, and Immunology, Vol. 33, No. 1, pp. 19-28 (1989), "The disinfecting effect of Persteril in combination with cleaning agents"<img he="6" id="000002" wi="80" file="2_0003545762.tif" img-format="tif" img-content="drawing" />The shelf life of the Perstil-stabilized peracetic acid aqueous solution was investigated. They suggested that peracetic acid should not be used in combination with basic cleaning agents. This is because the spore-killing effect of peracetic acid was significantly reduced at pH 9. Tenside In a paper by Hauthal et al., entitled "Study on the Mechanism of Bleach Activation," Surf.Det., Vol. 27, No. 2, pp. 187-193, on peroxyacetic acid with hydrogen peroxide or sodium perborate. The effect of pH on the bleach activators diacetyldioxohexahydrotriazine (DADHT) and tetraacetylethylenediamine (TAED) in formation has been investigated. This paper shows that at higher pH values, the rate of peroxyacetic acid formation increases but becomes unstable and decomposes more rapidly into oxygen and acetic acid. Although these documents mention the effect of pH, they are mixed with water at room temperature to rapidly form a bactericidal effective concentration of peracetic acid, and are sufficiently stable for a period of at least 8 hours. No teaching or proper suggestion has been made regarding suitable powder formulations that guarantee bactericidal activity. The present invention provides novel and improved sterile formulations that overcome the problems mentioned above and other problems. Abstract of the Invention According to the present invention, there is provided a powder mixture consisting of a perborate, a rapid acetylating agent, a slow acetylating agent, and a buffer. According to a more limited aspect of the invention, the buffer buffers the pH of the formed solution to a pH between 7.5 and 9 when the composition is mixed with water, and 10 ° C-60. The temperature should be ° C, preferably 25 ° C. According to another more limited aspect of the invention, the rapid acetylating agent comprises an acetylating agent that produces at least two acetyl groups, and the slow acetylating agent is active in producing at least one acetyl group. Contains agents. According to a more limited aspect of the invention, the rapid acetylating agent comprises TAED, and the slow acetylating agent comprises acetylsalicylic acid. According to a more limited aspect of the invention, the buffer pH 8. Buffer to less than 5. According to a further aspect of the invention, an additional buffer is added to the solution near the peak of peracetic acid production to reduce the pH and bring it closer to neutral pH for longer term stability. One advantage of the present invention is to provide a composition that can be mixed with room temperature water that can be used to form an effective liquid fungicide. Another advantage of the present invention is that the resulting fungicide is stable and effective over a long duration. This does not require an exact period of criticality of use and facilitates use by inexperienced technicians. Further advantages of the present invention will be apparent to those skilled in the art by reading and understanding the detailed description of the preferred embodiments below.

[Simple explanation of drawings]

The present invention may take the form of various components and combinations of components, as well as various steps and combinations of steps. The drawings are for the purpose of explaining preferred embodiments only and should not be construed to limit the invention. FIG. 1 is a graph of peracetic acid parts per million (ppm) over time for TAED, acetylsalicylic acid, and blends of TAED with acetylsalicylic acid. Figure 2 shows the ppm of peracetic acid over time for blending TAED and acetylsalicylic acid buffered at different pH. FIG. 3 is a graph of peracetic acid over time showing the effect of lowering pH after the first formation of peracetic acid. Detailed Description of Preferred Embodiments A packet with two compartments holds a powder formulation containing a perborate in one compartment and an acetylating agent in another compartment. The compartment also holds a buffer for buffering pH, corrosive substances, surfactants, sequestrants and the like. Acetylating agents include relatively rapid acetylating agents (ie, those that produce two or more acetyl groups, such as TAED). Preferably, powdered TAED is a trademark of MYKON.^TMIt is a methylcellulose encapsulated form of TAED sold at. As shown in curve 10 of FIG. 1, TAED and perborate (eg, sodium perborate) react rapidly in water to form bactericidal effective concentrations (eg, 2000 ppm) of peracetic acid. However, the concentration of peracetic acid tends to decrease relatively quickly over time. On the other hand, as shown by curve 12, acetylsalicylic acid (a slow acetylating agent that produces only one acetyl group) requires a relatively long duration to reach the maximum peracetic acid concentration. However, the peracetic acid produced by the acetylsalicylic acid acetylating agent is more stable and does not decay or decompose rapidly. TAED and acetylsalicylic acid are preferably mixed in a molar ratio of 1: 1 in order to rapidly generate stable peracetic acid at bactericidal effective concentrations over a long duration. As shown in curve 14, the peracetic acid solution produced from this mixture is more stable and sterilized over a longer duration than when formed with either TAED alone or acetylsalicylic acid alone. Is effective. Since 1 mol of TAED produces 2 mol of peracetic acid and 1 mol of acetylsalicylic acid produces 1 mol of peracetic acid, a preferred embodiment is to achieve a preferred 1: 1 molar ratio. Mix 0.5 mol of TAED with 1 mol of acetylsalicylic acid. Appropriate amounts of sodium perborate, TAED, and acetylsalicylic acid were added in a preselected amount of water, 2, Generates 000 ppm of peracetic acid or other bactericidal effective amount. The composition further comprises benzotriazole or tritriazole tolytriazole), or other compositions that suppress the corrosion of copper and brass in the presence of strongly oxidizing compounds. Azole, benzoate, and other five-membered ring compounds may also be acceptable as copper and brass corrosion inhibitors. Phosphate buffers pH and suppresses brass and iron corrosion. To control iron and steel corrosion, phosphate is present in the resulting solution at a final concentration of at least 1.25% by volume. Higher phosphonate concentrations may be provided for effective pH buffering. Molybdates, chromates, dichromates, tungstates, vanazine salts, borates, and combinations thereof, of phosphates to control corrosion of iron and steel and buffer pH. It can be used instead or in addition to phosphate. To control the precipitation of calcium and magnesium salts in hard water, the powder composition preferably comprises hexametaphosphate or another sequestrant. The sequestrant further removes substances such as cobalt and suppresses the precursor reaction. Wetting or cleaning agents are also present at concentrations that form 0.001% to 1.0% (weight / volume) concentrations in the resulting solution. Includes diacetyl diohexahydratriazina (DADHT), sodium nanonoyl oxygenzene sulfonate, pentaacetylglucose (PAG), and tetra acetyl glycouril (TAG). Other acetyl donors are also intended. With reference to FIG. 2, it is observed that pH has a dramatic effect on the safety and longevity of the resulting solution. TAED against acetylsalicylic acid 1: For the preferred embodiment of 1, a substantially flat peracetic acid concentration curve 20 is achieved for a pH of 8.3 in the range of 1-8 hours. As the pH increases to a pH of 8.51, the rate of peracetic acid formation increases, but the stability of peracetic acid decreases, as shown in curve 22. As shown in curve 24, increasing the pH to 8.86 further increases the initial peracetic acid formation rate, but the resulting solution becomes more unstable over time. As shown in FIG. 3, a high pH aids in the rapid formation of peracetic acid, while a lower, closer to neutral pH aids in the long-term stability of the peracetic acid produced. In the embodiment shown in FIG. 3, TAED reacts with sodium perborate at a relatively high pH (eg, pH = 8.9) until the peracetic acid concentration is reached to a maximum. The pH is then adjusted by adding an effective amount of buffer in the solution or by another method of increasing the effective amount of buffer. As shown in curve 30, when the pH is lowered to about 7.5, the peracetic acid concentration remains substantially stable. In contrast, as shown in curve 32, if the pH is not adjusted and is slowly reduced from 8.9 and if it is reduced, the concentration of peracetic acid decreases, reflecting the reduced stability. The present invention has been described in a preferred embodiment. It is clear that changes and modifications will be made as those skilled in the art read and understand the detailed description above. The present invention is intended to be construed to include all such modifications and modifications within the scope of the appended claims or equivalent. Raising to 86 further increases the initial peracetic acid formation rate, but the resulting solution becomes more unstable over time. As shown in FIG. 3, a high pH aids in the rapid formation of peracetic acid, while a lower, closer to neutral pH aids in the long-term stability of the peracetic acid produced. In the embodiment shown in FIG. 3, TAED reacts with sodium perborate at a relatively high pH (eg, pH = 8.9) until the peracetic acid concentration is reached to a maximum. The pH is then adjusted by adding an effective amount of buffer in the solution or by another method of increasing the effective amount of buffer. As shown in curve 30, when the pH is lowered to about 7.5, the peracetic acid concentration remains substantially stable. In contrast, as shown in curve 32, if the pH is not adjusted and is slowly reduced from 8.9 and if it is reduced, the concentration of peracetic acid decreases, reflecting the reduced stability. The present invention has been described in a preferred embodiment. It is clear that changes and modifications will be made as those skilled in the art read and understand the detailed description above. The present invention is intended to be construed to include all such modifications and modifications within the scope of the appended claims or equivalent. Raising to 86 further increases the initial peracetic acid formation rate, but the resulting solution becomes more unstable over time. As shown in FIG. 3, a high pH aids in the rapid formation of peracetic acid, while a lower, closer to neutral pH aids in the long-term stability of the peracetic acid produced. In the embodiment shown in FIG. 3, TAED reacts with sodium perborate at a relatively high pH (eg, pH = 8.9) until the peracetic acid concentration is reached to a maximum. The pH is then adjusted by adding an effective amount of buffer in the solution or by another method of increasing the effective amount of buffer. As shown in curve 30, when the pH is lowered to about 7.5, the peracetic acid concentration remains substantially stable. In contrast, as shown in curve 32, if the pH is not adjusted and is slowly reduced from 8.9 and if it is reduced, the concentration of peracetic acid decreases, reflecting the reduced stability. The present invention has been described in a preferred embodiment. It is clear that changes and modifications will be made as those skilled in the art read and understand the detailed description above. The present invention is intended to be construed to include all such modifications and modifications within the scope of the appended claims or equivalent. When and if reduced slowly from 9, the concentration of peracetic acid decreases, reflecting the reduced stability. The present invention has been described in a preferred embodiment. It is clear that changes and modifications will be made as those skilled in the art read and understand the detailed description above. The present invention is intended to be construed to include all such modifications and modifications within the scope of the appended claims or equivalent. When and if reduced slowly from 9, the concentration of peracetic acid decreases, reflecting the reduced stability. The present invention has been described in a preferred embodiment. It is clear that changes and modifications will be made as those skilled in the art read and understand the detailed description above. The present invention is intended to be construed to include all such modifications and modifications within the scope of the appended claims or equivalent.