Drug – bio-affecting and body treating compositions – Inorganic active ingredient containing – Peroxide or compositions of or releasing gaseous oxygen or...
Reexamination Certificate
2001-12-28
2004-10-12
Pak, John (Department: 1616)
Drug, bio-affecting and body treating compositions
Inorganic active ingredient containing
Peroxide or compositions of or releasing gaseous oxygen or...
C424S601000, C424S602000, C424S603000, C424S604000, C424S605000, C424S606000, C424S126000, C424SDIG006, C514S075000, C514S102000, C514S108000, C514S112000, C514S114000, C514S140000, C514S141000, C514S142000, C514S143000, C514S529000, C514S547000, C514S549000, C514S550000, C514S552000, C514S553000, C514S557000, C514S558000, C514S559000, C514S560000, C514S574000, C514S576000, C514S578000, C514S709000, C514S711000, C514S970000, C514S973000, C422S012000, C422S028000, C504S151000
Reexamination Certificate
active
06803057
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to disinfectants and, in particular, it relates to hydrogen peroxide solutions with improved disinfectant and antimicrobial properties.
BACKGROUND TO THE INVENTION
A wide range of disinfectants is known, as discussed for example in Disinfection, Sterilization, and Preservation, edited and partially written by Professor Seymour S. Block, Fourth Edition, published 1991 by Lea & Febiger, Pennsylvania. Certain peroxygen compounds, chlorine compounds, phenolics, quaternary ammonium compounds and surface active agents are known for their germicidal properties. The rate of disinfection is relatively slow in many cases, and some compounds emit volatile organic compounds or leave a persistent residue in the environment.
Hydrogen peroxide is finding favour in many applications because its breakdown products, water and oxygen, are innocuous, and it tends to have broad spectrum antimicrobial activity. Broad spectrum activity is important in situations where harmful organisms are present but their identity is not known.
As hydrogen peroxide tends to be unstable and decomposes over time, steps must be taken to stabilize the hydrogen peroxide solutions for storage purposes. Various ways have been proposed to improve the stability of hydrogen peroxide compositions. For example, sodium stannate, sodium nitrate, and diethylene triamine penta(methylenephosphonic acid) have been reported as being useful as stabilizers, as disclosed in U.S. Pat. No. 5,523,012 to Winterton et al., which issued Jun. 4, 1996.
A major drawback of most disinfectants used heretofore has been the length of time needed to reduce the bacterial count after the disinfectant has been applied to a bacterially contaminated material. For example, it may take 30 minutes or more after application of the disinfectant to disinfect a treated surface. In many circumstances this rate of disinfection is far from satisfactory.
Combinations of hydrogen peroxide with various surfactants are known. For example, Winterton et al. discloses, in U.S. Pat. No. 5,523,012, a buffered disinfecting solution for contact lenses, which has from about 0.1% to about 1.0% of an ocularly compatible surfactant. Winterton discloses that, in one experiment, addition of about 0.4% anionic sulfosuccinate surfactant improved the killing time for
aspergillus fumigatus
to 6.9 minutes, compared to 9.4 minutes for a solution containing 0.1% nonionic surfactants. However, even 6.9 minutes is far too long for many applications.
The present invention is directed to improving the efficacy of hydrogen peroxide based solutions.
SUMMARY OF THE INVENTION
Accordingly, the invention provides an aqueous solution having a pH of from about 0.5 to about 6 and comprising i) hydrogen peroxide in a concentration of from about 0.01 to about 20 wt./wt. % of the solution, ii) at least one phosphorus-based acid in a concentration range of from about 0.05 to about 8 wt./wt. % of the solution, and iii) at least one anionic surfactant selected from the group consisting of C8 to C16 alkyl aryl sulfonic acids and alkali metal, ammonium, calcium and magnesium salts thereof, sulfonated C12 to C22 carboxylic acids and alkali metal, ammonium, calcium and magnesium salts thereof, C6 to C22 alkyl diphenyl oxide sulfonic acids and alkali metal, ammonium, calcium and magnesium salts thereof, naphthalene sulfonic acids and alkali metal, ammonium, calcium and magnesium salts thereof, C8 to C22 alkyl sulfonic acids and alkali metal, ammonium, calcium and magnesium salts thereof, alkali metal, ammonium, calcium and magnesium C8 to C18 alkyl sulfates, alkyl or alkenyl esters or diesters of sulfosuccinic acid in which the alkyl or alkenyl groups independently contain from six to eighteen carbon atoms and alkali metal, ammonium, calcium and magnesium salts thereof, and mixtures thereof, in a concentration range of from about 0.02 to about 5 wt./wt. % of the solution.
The phosphorus-based acid may be selected from the group consisting of the derivatives of phosphorous oxides in which the phosphorous atom is in the +5 oxidation state, phosphonic acids having 1 to 5 phosphonic acid groups and salts thereof, and mixture thereof. Preferably, the phosphorus-based acid is selected from the group consisting of phosphoric acid, 1-hydroxyethylidene-1,1,-diphosphonic acid, and mixtures thereof.
The solution may contain an additional component selected from the group consisting of emulsifiers, hydrotropes, detergents and mixtures thereof in a concentration of up to about 3 wt./wt. % of the solution, and preferably in a concentration of from about 0.04 to about 3 wt./wt. % of the solution. The emulsifiers and detergents may be polyoxyethylene surfactants. The hydrotrope may be selected from the group consisting of alkylated sulfonated diphenyl oxides, alkylated sulfonated diphenyl oxide salts, and mixtures thereof, and preferably is a C6 alkylated sulfonated diphenyl oxide disodium salt.
The anionic surfactant is preferably dodecyl benzene sulfonic acid or an alkali metal salt or ammonium salt thereof.
Preferably, the hydrogen peroxide concentration may be from about 0.05 to about 8 and, more preferably from about 0.5 to about 8, wt./wt. % of the solution.
Also preferably, the phosphorus-based acid may be present in a concentration of from about 0.2 to about 8 wt./wt. % of the solution.
The anionic surfactant is preferably present in a concentration of from about 0.08 to about 5 wt./wt. % of the solution.
Preferably, the pH of the solution is from about 0.7 to about 3.5.
The solution may further contain a corrosion inhibitor in a concentration of from about 0.05 to about 10 wt./wt % of the solution. Also, the solution may contain a monocarboxylic acid, a polycarboxylic acid, or mixtures thereof, in a concentration of from about 0.05 to about 4 wt./wt. % of the solution. The solution may also contain an alcohol comprising one to six carbon atoms in a concentration of from about 0.1 to about 10 wt./wt. % of the solution.
In accordance with another aspect of the invention, the present solution may be made in concentrated form for dilution by the end user with water.
In accordance with a further aspect, the invention provides a powdered formulation which can be diluted with water to produce the present aqueous solution.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
In the past few years, efforts have been concentrated on developing chemicals that will be highly effective against microorganisms when highly diluted, will be low in toxicity to humans and other animals, and will not injure the environment. Of all the known disinfectants and antimicrobials, hydrogen peroxide appears to have exceptional potential, especially in terms of toxicity and injury to the environment because the decomposition products are benign. For example, at concentrations of 1-3 wt./wt. % aqueous solution, hydrogen peroxide is considered non-corrosive and non-irritating; at concentrations of 3-7 wt./wt. % aqueous solution, hydrogen peroxide is considered non-corrosive but an eye irritant; and at concentrations of above about 8 wt./wt. % aqueous solution, hydrogen peroxide is considered corrosive, more so at higher concentrations, and also a strong oxidizing agent.
The higher concentration levels of hydrogen peroxide solutions required to provide fast, effective action are not practical or economically viable, may be subject to hazardous goods regulations and require special precautions for handling and use. Heretofore, one of the major drawbacks of hydrogen peroxide, in low concentrations, is that its antimicrobial action is too slow. A second major drawback is that it has not been considered possible to stabilize the peroxide sufficiently to make the solution commercially acceptable. For example, prior references indicate that a 0.1 wt./wt. % aqueous solution of hydrogen peroxide requires 60 minutes to disinfect surfaces contaminated with
staphylococcus aureus
, whereas a 25.8 wt./wt. % aqueous solution of hydrogen peroxide requires only 20 seconds to disinfect surfaces contaminated with
Ramirez Jose A.
Rochon Michael J.
Clark & Brody
Pak John
Virox Technologies Inc.
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