AP935A

AP935A - Quick acting chemical sterilant.

Info

Publication number: AP935A
Application number: APAP/P/1998/001341A
Authority: AP
Inventors: Norman A Miner; William Woller; Edward L Anderson; David W Hobson
Original assignee: Healthpoint Ltd
Priority date: 1996-02-12
Filing date: 1997-02-11
Publication date: 2001-02-05
Also published as: BR9707438A; WO1997028691A1; JP3334055B2; OA10836A; AP9801341A0; BR9707438B1; EA001112B1; EP0881883B1; US5827542A; DE69714018D1; JP2000503662A; KR100318787B1; NO320501B1; EP0881883A1; PT881883E; HK1017234A1; DK0881883T3; KR19990082651A; NO983680D0; CN1213951A

Abstract

A low odor ,aqueous quick acting room disifectant lotion primarily useful for medical instrument to disinfect within a half an hour or less.The composition comprises a reacting synergistic combination of hydrogen peroxide and from about 1% to 30% by weight of a water soluble organic acid or salt form thereof with the acid preferably being selected from the group constisting of malonic and succinic acids

Description

QUICK ACTING CHEMICAL STERILANT

BACKGROUND OF THE INVENTION

Medical, dental and other instruments are often made of high quality stainless steel that can be cleaned and sterilized between uses for different patients by high temperature steam under pressure. This sterilization procedure is quick, reliable, odorless, non-toxic and inexpensive. In contrast to this situation, more and more lo instruments are now made of heat-sensitive plastic, rubber, glass lenses and electronic components. These flexible, flexible-lensed, and rigid-lensed instruments allow relatively non-invasive diagnostic and treatment procedures within the body. The non-invasive procedures allowed by these heat.-sensitive instruments are responsible for great advances in medical practice. During UBe, these instruments can be carvcaminated with deadly pathogens such·, as the Human Immunodeficiency Virus (HIV), hepatitis viruses, and antibiotic drug-resistant tuberculosis and other bacteria.

For these reasons, it is imperative that these heat-sensitive instruments be sterilized of all microbes prior to each uee. The chemical germicides available for sterilization of heatsensitive instruments have in the past had many problems that made their use difficult.

The antimicrobial properties of hydrogen peroxide have been known for many.years. However, 6% hydrogen peroxide requires a minimum of 6 hours at room temperature to pass the standard Association of Official Analytical Chemists (AOAC) Sporicidal Test. This is the test that defines •’sterilant for liquid chemical germicides in the United States. The antimicrobial properties of. peracetic acid are also yell known. _r Peracetic . acid has.. a. very Bharp. .pungent odor, and is known as a. tumor-promoting agent when^tested;on.mouseskin. For these reasons , .the use of .peracetic acid as.a_rchemical sterilant is 11ml ted to J.ow.. concentrations used _?with enclosed systems. .,. .. . . ,_r .. . , ....... ..... .

at· -.: k . y:: . iJ...... . ’/ο Λ ' c.^q£f.· el i r.

’/P/ 9 8/0 1 3 4 1

Antimicrobial synergism between hydrogen peroxide and peracetic acid is a well established fact. Such compositions are prepared by mixing hydrogen peroxide and acetic acid to give equilibrated solutions of hydrogen peroxide, acetic acid, and peracetic acid. There is a great deal of scientific and patent literature regarding hydrogen peroxideperacetic acid solutions for sterilization. By.way of example only, Minntech Corporation of Minneapolis, Minnesota, has a kit or sterilization console for disinfecting with hydrogen peroxide-peracetic acid solutions {U.S. Patent 5,400,818). However, this combination is limited by the same problems of pungent odor and potential toxicity as peracetic acid alone. This often means that such formulations are used at such dilute concentrations that rapid sporicidal activity is lost, nc the solutions are limited to enclosed systems that contain the pungent fumes. ·

Steria Corporation of Mentor, Ohio, markets a Steris System 1 product. This uses a low concentration of peracetic acid (about 0.2%) contained within'a machine, and is heated to 122 *F to achieve rapid sterilization. The relatively low peracetic acid concentration, coupled with the high temperature, breaks down the peracetic acid, limiting it to one single use cycle. The heated, enclosed, single-use machine system is expensive and lees than desirable.

Another chemical, sterilant is 2% alkaline glutaraldehyde. Glutaraldehyde requires about 10 hours at 25*C to pass the AOAC Sporicidal Test. Because of this long exposure time, the use of glutaraldehyde is usually compromised, to accept disinfection from a shorter exposure time rather than the safer condition of sterilization. Furthermoreglutaraldehyde has an odor that irritates eye, nose, and thrddt^mucous membranes; Repeated exposure to

AP/P/ 9 8/0 1 3 41 ' glutaraldehyde catises headaches' and allergic reactions for some'peoalei 'For these reasons, glutaraldehyde is a less than desirable chemical‘germicide. ^i: ^: '

Many chemicals that contain chlorine are rapidly' sporicidal and capable of sterilization. Examples are

AP O0935 bleach, the active agent of which is HOC1, HCIO2, ClO^, and HCl- However, while these chemicals are rapidly sporicidal, they are too corrosive to metals and elastomers to find any practical use in sterilization of medical, dental and other instrumentn.

It can therefore be seen that there is a continuing need for an effective, practical, safe, affordable sterilant for heat-sensitive instruments, as well as for all applications that are beyond the scope of steam sterilization. This invention has as its primary objective the fulfillment of this need.

SUMMARY OF THE INVENTION

This invention relates to a rapid acting room temperature sterilant. It is a low odor, aqueous disinfecting solution having a pH within the range of 276.

It comprises in combination a solution of from about 1% to about 30% by weight of peroxide capable of releasing hydroxyl free radicals, and from about 1% to about 30% by weight of a water soluble organic acid or salt form of a C3 or higher mono, or n di-, tri-, or poly carboxylic organic acid, with the organic acid preferably selected from the group consisting of malonic acid and succinic acid, or combinations thereof- It is believed there may be a reaction between the .25 peroxide and carboxylic acids that produce a third chemical or condition that causes rapid kill of bacterial spores and other microbes at ambient temperatures (18*C-24*C) in short times (i.e.. within 30 minutes). The carboxylic acids that can be uaed with peroxides can be selected from a large group to be relatively odor-free, non-toxic, soluble and inexpensive.

AP/P/ 98/01341

£.C.! X

DETAILED DESCRIPTION OF’THE INVENTION ''

The sterilizing and 'disinfecting solutions of ‘this^fii35¹ invention have a variety ^:of uses'. ' The 'solutions‘ have eixeeilWtit sterilization 'and 'disinf ecting properties and^xcan ’·' be tiseci to sterilize sophisticated medical instruments ’such . 1.. .- .1 —· .::

r-r.:

r3

AP 00935 as endoscopes without causing damage to sensitive parts of such instruments.

The fact that this process can be used with endoscopic instruments is significant since relatively non-invasive endoscopic procedures have revolutionized the way that surgery is performed. As earlier mentioned, few rigid or flexible endoscopes can.be sterilized by the quick and sure method of steam sterilization because the piastre, rubber and precisely-positioned glass lenses of endoscopes make them incompatible with the heat of a steam sterilizer. Instead they must be sterilized using lower temperatures and typically slower processes. They also must use a sterilizing solution that is non-corrosive.

Endoscopes are but one example of the type of instrument that can ae effectively sterilized with the present compositions. Conventional surgical instruments of all types, microsurgery instrument sets, anesthesia equipment, etc. can also be treated. Generally, the composition disclosed herein can be used for sterilization of any products that enter sterile tissue or the vascular system or have tissue contact during any surgeries. Necessarily, if the solution is effective for these critical medical instruments, it also can be used for intermediate level and low level instruments and surfaces. Because the formulation is relatively odorlees and non-toxic, one can sterilize surfaces that formerly were only disinfected or sanitized, or one can dilute the formula for disinfection rather than sterilization. The composition may also be used as an antiseptic to kill germs on skin. It is therefore versatile in use.

It had previously been thought that effectiveness of hydrogen peroxide and .peracetic--aci.d combinations. to.-pass standard. ’’AOAC sterilization tests was. due to the . substantial, enhancement of .formation, of free hydroxy radicals

....from .the pi^r_Acid: in._Tcombination, with hydrogen, peroxide. .Accordingly, it was ..thought , necessary to add peroxyacetic acid directly to germicidal formulations. Quite

AP/P/ 9 8/0 1 3 4 1

ΑΡ 0 0 9 3 5 surprisingly, the inventors found that it was not necessary to add the toxic and malodorous peracetic acid to sterilizing formulations. Instead, certain lower carboxylic acids selected for their solubility, lack of odor, and non-toxic nature can be used in combination with hydrogen peroxide to achieve sterility at ambient temperatures and short exposure times. In particular, the carboxylic acid could be a C3 or higher mono or a di- or poly carboxylic acid of up to C^2 chain length and can be saturated or unsaturated. As a result of this composition, complex and expensive equipment needed to contain toxic chemicals can be eliminated, and since the acids employed are weak organic acids, corrosion of materials is significantly reduced. As a result, providing the levels herein described are used, there is a reacting 01 synergistic relationship between the defined water soluble organic acid and the peroxide such that even at lower temperatuiiis non-corrosive sterilization is achieved. Moreover, rhe chemicals are generally inexpensive and odorfree, and are therefore economically and simply packaged. Of course, less odor and less toxic mean that higher concentration can be used with accompanying faster rate of sterilization. At higher exposure temperatures of 30, 40, or 50 *C, for example, the exposure time needed to achieve sterilization is even faster than at ambient temperatures.

The first component of the composition is from about 1% to about 30% by weight .of a peroxide. Preferably, the amount of peroxide is from about 1% by weight to about 12% by weight of the disinfecting solution, and most preferably from about 6% by weight to about 10% by weight of the disinfecting solution. The preferable.concentration of peroxide may be varied depending on the. application from lower concentration £or._;-an antiseptic, to ^higher concentrations for a . lowtemperature, -- rapid-acting .sterilant. The peroxide of-choice is, of · course,. the: most. commonly. available peroxide, ...hydrogen peroxide. However, the invention is not limited[to hydrogen ,· peroxide,;and other peroxy compounds may be employed. These include j, i or_; example,-perborates, .saturated >. and-unsaturated

AP/P/ 9 8/ 0 1 3 41

ΑΡ υ Ο 9 3 5 peralkanoic acids such as peracetic acid, performic acid, perpropionic acid, etc. The critical factor is that it be a water soluble peroxide compound that is compatible with the weak carboxylic acid component.

The weak carboxylic acid component of the present invention is preferably a di- acid of lower C^2 loss carbon length carboxylic acid preferably selected from the group consisting of malonic acid and succinic acid. Also, examples ci acids in this class would be malic, oxalic and tartaric acids. These acids, when in the proper concentrations, are low odor, reasonably soluble and noncorrosive. The amount of the carboxylic acid component generally would be within the range of from about 1.0% by weight to 30% by weight of sterilizing or disinfecting solution, preferably from about 1% by weight to about 12% by weight of the solution, and most preferably from about 3% by weight to about 6% by weight of the solution composition. As with the peroxide, the preferred concentration of carboxylic acids is related to the intended end use.

Generally speaking, and as a guideline, the peroxide component should have a concentration of within the range of 0.2M to about 10M, preferably within the range of 0.2M to 4.0M. The organic acid component should have a concentration within the range of 0.05M to 4.0M, and preferably of 0.05M to

2. OH.

While acetic acid is unacceptable by itself because of its normal pungent odor, it is possible that some acetic acid, in combination with other of the acids described here, can be successfully used. Thus the key to the present invention is the presence of the herein-described combination or perhaps the reaction product^thereof.

-Generally,^?the amount of peroxidecomponent and the amount of carboxylic acid component7&re balanced'such.that the pH will be within the’range of about 2.0 to 6.0',>-35 - -preferably-about 3.0 to 5.O'.' -^1:i -· .η·*··*:!

-While ’a'⁴suitable sterilizing-and disinfecting-solution ’ can be achieved with these^: two 'bomponente^: only, as is

AP/P/ 98/01341

AP u Ο 9 3 5 understood by those skilled in the art, other ingredients may be added. In fact, the sterilizing and disinfecting capabilities can be enhanced by adding a small amount- of detergent such as nonionic or anionic detergent. The amount of detergent can be within the range a£ from about 0-05% by weight to about 1.0% by weight, preferably from about 0.1% by weight to about 0.5% by weight. The amount of detergent should be enough to enhance the sterilization and disinfection, but less than the amount which would provide substantial sudsing.

Suitable synthetic detergents are well known to those of ordinary «kill in the art, but generally these surface active agents, can be selected from the group consisting of anionic and nonionuc surfactants. Non-ionic, ether-linked surfactants such as Laureth®4 or Laureth®23 are preferred.

. Alkyl sulfate surfactants are a type of anionic surfactant of importance for use herein. Alkyl sulfates have the general formula ROSO3H wherein R preferably is a C^q-C24 hydrocarby1, preferably an alkyl or hydroxyalkyl having a ²⁰ ^iq-Cjo alkyl component, more preferably a Ci2“^ci8 alkyl or hydroxyalkyl, and M is H or a cation, e.g., an alkali metal cation (e.g., sodium, potassium, lithium), substituted or unsubBtituted ammonium cations such as methyl-, dimethyl-, and trimethyl ammonium and quaternary ammonium cations, e.g., tetramethylammonium and dimethyl piperdinium, and cations derived from alkanoiamines such as ethanolamine, diethanolamine, triethanolamine, and mixtures thereof, and the like. Typically, alkyl chains of C12-I6 ^are preferred for lower wash temperatures (e.g., below about 50*C) and Cjg_

28 alkyl chains are preferred for higher wash temperatures .

(e.g., above about :50’C).. ; , _____ . _...

>· r. iAlkyl-alkoxylated ?sulfate surfactants are another , -category^ of :useful anionic._:;surfactant. These surfactants are water, soluble -salts or acids .typically of the formula ,·,_;τ_Λ

RO (A) jaSCb M -wherein R · is an j.unsubstituted . C10 ”^c2 4 -^lkyl '

.. ;hydroxyalkyl · group having-a C10-C24 alkyl component,r_f preferably =a 0^2^20 alkyl .or .hydroxy alkyl, .more preferably

AP/P/ 9 8/0 1 3 4 1 ^c12“^c18 alkyl or hydroxyalkyl, A is an ethoxy or propoxy unit, m is greater than zero, typically between about 0.5 and about 6, more preferably between about 0.5 and about 3, and M is H or a nation which can be, for example, a metal cation (e.g., sodium, potassium, lithium, calcium, magnesium, etc.), ammonium or substituted-ammonium cation. Alkyl ethoxyiated sulfates as well as alkyl propoxylated sulfates .are contemplated herein. Specific examples of substituted ammonium cations include methyl-, dimethyl-, trimethylammanium and quaternary ammonium cations, such as tetramethyl-ammonium, dimethyl piperydinium and cations derived from alkanolamines, e.g., monoethanolamine, diethanolamine, and triethanolamine, and mixtures thereof. Exemplary surfactants are Cj^-Cig alkyl polyethoxylate (1.0) sulfate, Cj2^^18 alkyl polyethoxylate (2.25) sulfate, alkyl polyethoxylate (3.0) sulfate, and C alkyl polyethoxylate (4.0) sulfate wherein M is conveniently selected from sodium and potassium.

Other auiionic surfactants useful for detersive purposes can also be included in the compositions hereof- These can include Belts (including, for example, sodium, potassium, ammonium, and substituted ammonium salts such as mono-, diand triethanolamine salts) of soap, Cg-C2<j linear alkylbenzenesulphonates, Cg-C22 Primary ox secondary alkanesulphonates, Cg-C24 olefinsulphonates, sulphonated polycarboxylic acids, alkyl glycerol sulfonates, fatty acyl glycerol sulfonates, fatty oleyl glycerol sulfates, alkyl phenol ethylene oxide ether sulfates, paraffin sulfonates, alkyl phosphates, isothionates such as the acyl isothionates, N-acyl taurates, fatty acid amides of methyl tauride, alkyl succinamates and sulfosuccinateB, .monoesters of .*·.··;, sulfosuecinate ^(especially saturated and.unsaturated Ci2“Cig monoestern) ‘diesters of sulfosuecinate ’(especially .saturated and ^Juiieaturated Cg-C^ “diesters) /· N-acyl sarcosinates sulfates/of alkylpolysaccharides such as-the-sulfates of alkylpolyglucoside, branched primary alkylτsulfates; alkyl •polyethoxy -carboxylates such as those ...of the ^formula ~

AP/P/ 9 8 i 0 13 4 1

ΑΡ υ ϋ 9 3 5

RO(CH₂CH₂O) i/CH₂C00-M+ wherein R is a Cg-C₂2 alkyl, k is an integer from 0 to 10, and M is a soluble salt-forming cation, and fatty acids esterified with isethionic acid and neutralized with sodium hydroxide. Further examples are given in Surface Active Agents and Detergents (Vol. I and II by Schwartz, Perry and Berch).

Suitable ncnionic detergent surfactants are. generally disclosed m U.S. Pat. 3,929,678, Laughlin et al., issued Dec. 30, 1975, at column 13, line 14 through column 16, line 6, incorpoirated herein by reference. Exemplary, non-limiting classes of useful nonionic surfactants are listed below.

The polyethylene, polypropylene, and polybutylene oxide condensates of alkyl phenols. In general, the polyethylene oxide condensates axe preferred. These compounds include the condensation products of alkyl phenols having an alkyl group containing from about 6 to about 12 carbon atoms in either a *

straight chain or branched chain configuration with the alkaline oxide. These compounds are commonly referred to as alkyl phenoL alkoxylates, (e.g., alkyl phenol ethoxylates).

The condensation products of aliphatic alcohols with from about L to about 25 moles of ethylene oxide. The alkyl chain of tae aliphatic alcohol can either be straight or branches, primary or secondary, and generally contains from about 8 to about 22 carbon atoms. Particularly preferred are the condensation products of alcohols having an alkyl group containing from about 10 to about 20 carbon atoms with from about 2 to about 18 moles of ethylene oxide per mole of alcohol.

The condensation products of ethylene oxide with a hydrophobic base farmed by the condensation of propylene oxide with propylene glycol.’ Examples of compounds of this type.include certain of the commercially-available Pluronic TM surfactants. marketed by BASF.

The condensation products of ethylene , oxide with the product resulting from the, reaction of propylene’oxide and , V :·? . , ( . h·'/ . -. i* .:- r - .4_ |___N . _ J <. __ * . J_ w * _ . _ t *' · ethylenediamine

Examples of this type of. nonipnic

-?r,G Λ

AP/P/ 9 8 / 0 1 3 4 1

AP υ Ο 9 3 5

2S surfactairt. include certain of the commercial) y available Tetronic TM compounds, marketed by BASF.

Semi-jjolar nonionic surfactants are a special category of nonionic surfactants which include water-soluble amine oxides containing one alkyl moiety of from about 10 to about 18 carbon atoms and 2 moieties selected from the group consisting of alkyl groups and hydroxyalkyl groups containing from about 1 to about 3 carbon atoms; water-soluble phosphine oxides containing one alkyl moiety of from about 10 to about 18 carbon atoms and 2 moieties selected from the group consisting of alkyl groups and hydroxyalkyi groups containing from about 1 to about 3 carbon atoms; and water-soluble sulfoxides containing one alkyl moiety of from about 10 to about 18 carbon atoms 31 and a moiety selected from the group consisting of alkyl and hydroxyalkyl moieties of from about 1 to about 3 carbon atoms.

Semi-polar nonionic detergent surfactants include the amine oxide surfactants having the formula

ΟΤ

R³(OR⁴)XN(R⁵)2 ©

AP/P/ 9 8/01341 wherein R³ is an alkyl, hydroxyalkyi, or alkyl phenyl group or mixtures thereof containing from about 8 to about 22 carbon atoms; R⁴ is an alkylene or hydroxyalkylene group containing from about 2 to about 3 carbon atoms or mixtures thereof; x is from 0 to about 3; and each R⁵ is an alkyl or hydroxyalkyi group containing from about 1 to about 3 carbon atoms or a polyethylene oxide group containing from about 1 to about 3 ethylene oxide groups. The R⁵ groups can be attached to each other, e.g., through an oxygen or nitrogen atom, to' lonn a ring structure. These amine oxide surfactants in particular include CjqCxb alkyl dimethyl amine oxides and Cq-Ci₂ alkoxy ethyl £>·;' . ·: ·'.'·· ί v:.-'.'.'OS’ ”,, · axhydroxy ethyl amine oxides. ........

Alkyi polysaccharides disclosed in u/sV Pat .' 4,565,647, • ·· · . · · '·/,····-· , ·. .... -s, .·. 1 .·; ·.··., .. · _f. ,·<

Llenado, issued Jan. 21, 1986, having a hydrophobic group containing from about 6 to about 30 carbon atoms, preferably

AP U0935 from about 10 to about 16 carbon atoms and a polysaccharide, e.g., a poL/glycoside, hydrophilic group containing from about 1,3 co about 10, preferably from about 1.3 to about 3, most preferably from about 1.3 to about 2.7 saccharide units. Any reducing saccharide containing 5 or 6 carbon atoms can be used, e.g., glucose, galactose and galactosyl moieties can be substituted for the glucosyl moieties. (Optionally the hydrophobic group is attached at the 2-, 3-, 4-, etc. positions, thus giving a glucose or galactose as opposed to a glucoeide or galactoside). The intersaccharide bonds can be, e.g., between the one position of the additional saccharide units and the 2-, 3-, 4-, and/or 6- positions on the preceding saccharide units.

Fatty acid amide surfactants having the formula:

O

R⁶-C-N(R⁷)₂ wherein R^e is an alkyl group containing from about 7 to about 21 (preferably from about 9 to about 17) carbon atoms and each R⁷ is selected from the group consisting of hydrogen, Ci~C₄ alky J , C2.-C4 hydroxyalkyl, and —(C₂H4O)_XH where x varies from about 1 to about 3.

In addition to the above, if desired, corrosion inhibitors at very minor levels can be used, i.e. at levels of .01% to .1% on a weight basis. Suitable corrosion inhibitors can include those available and known, for example, complex fatty amine salts such as η,n’dibutylthiourea, etc.

Honionic ether linked surfactants are preferred such as Laureth®23 or Laureth®4.

In addition to all of the above, as is well understood by those skilled in the art, other minors can be employed to make the basic composition more pharmaceutically elegant.

AP/P/ 98 / 0 1 3 4 1

For example*, odorants can be added at very minor levels as can dyeri, diluents such as alcohol, buffers, etc. With the exception of diluents such as alcohols which are used at

ΑΡ υ ο 9 3 5 higher levels, the levels of these minors are generally not more than ..001% to .01% by weight.

The composition can be used as a sterilant for medical and dental equipment, implanted medical and dental devices and appliances, can be used as a disinfectant for inanimate surfaces, can be used as an antiseptic for skin disinfection, such as for patient preoperative skin disinfection or health personnel, a hand wash, may be used as a disinfectant, for contact lenses, an oral disinfectant or antiseptic, and can be used generally for conventional, intermediate and low level disinfection, and as a sterilant in industrial applications.

Packaging of the composition is not complex. It may be prepackaged in dry form if desired with instructions for mixing solutions on the spot, or it may be prepackaged in solution form.·, ideally in two packages (one the peroxide and one the organic acid component) to be mixed at point of use. This enhances freshness and accuracy of compliance with directions.

The following examples are offered to illustrate, but not limit, the process of the present invention and to demonstrate the surprising result that satisfactory results in comparison with acetic acid can be achieved with weaker longer chain acids such as succinic acid.

ί

Historically, the Environmental Protection Agency regulates germicides in the United States, and the test for a sterilizing claim (a sterilant) by a liquid germicide is the Association of Official Analytical Chemists (AOAC) Sporicidal Activity of Disinfectants Test 966.04. This test exposes spores dried onto carrier surfaces to the germicide. To make a label claim as a sterilant, a germicide must produce 720 sterile cylinders of 720 total cylinders within a specified, exposure time and temperature range. A legal definition of sterilant in the United States is one that can pass this test. In the following tests peroxide composition alone was compared with an acetic acid composition alone and with sodium acetate composition with regard to ability to

AP/P/ 98/01341

ΑΡ ο υ 9 3 5 sterilize carriers labeled with spores according to the methods of the AOAC Sporicidal Test.

TABLE I

Humber of Positive (+)

Cylinders per Total

Number Tested. 30 Min. Percent sterile

Formulation	Exposure at 20±i'C.	cylinders
6% * pH	4.7 20/20	Zero
6% H₂O₂ +
0.5% Acetic pH 2.7	Acid 2/20	90%
0.5% Acetic pH 2.8	Acid 20/20	Zero
6% H₂O₂ +
0.5% sodium pH €.7	Acetate 20/20	Zero

0.5% Sodium Acetate. 20/20 Zero pH 7.7

This lest was repeated with some modifications in an attempt tc· sterilize 100% of the C.sporogenes-labeled cylinders. The results were as follows.

AP/P/ 9 8 / 0 1 3 4 1

30			TABLE II
			Number of Positive	Percent
		Time in Min.	Cylinders (+) Per	Sterile
	Formulation	at 2o±l*c	Total Humber Tested	Cylinders
35	8% H₂O₂	30	20/20	Zero
	pH 4.5
	8% H₂O₂ +	10	9/20	55%
	2% Acetic Acid	20	0/20	100%
40	pH 2.4	30	0/20	100%
	8% H₂O₂ +	10	10/20	50%
	1% Acetic Acid	20	8/20	60%
	Ph 2.6	30	0/20	100%
45
	8% H₂O₂ +	10	11/20	45%
	0.5% Acetic Acid 20	9/20	55%
	pH 2.7	30	0/20	100%
50	2% Acetic Acid	30	20/20	Zero
	pH 2.7

AP 00935

Tests were done at ambient conditions comparing the rapid sporicidal activity of hydrogen peroxide in combination with the carboxylic acids acetic, malonic, succinic, glutaric and citric acids. Compositions from the data are reported in

Table III.

TABLE III

Sterilization of C.sporogenes-labeled porcelain cylinders by io formulations of H2O2 plus acetic, malonic, or succinic acid.

Percentage of Twenty ExpoBure Time c.sporog-enes-labeled

Formulation Min. sc 20 *c cylinders sterilized

8% plus	10	50%
1% acetic acid	20	80
pa 2.5	30	100
8% S₂O₂ Pl^us	10	zero %
1% malonic acid	20	40
pH 1.8	30	85
8% ^h2°2 Pl^U8	10	S%
0.5% malonic acid 20	25
pH 1.9	30	100
8% H₂O₂ plus	10	Zero %
1% succinic acid 20	IS
pH 2.4	30	95
Furthe r	tests	combined H2°2 with	glutaric acid and
citric acid.	The	results are shown in	Table IV and V.

AP/P/ 9 8 / 0 1 3 4 1 > . 14

ΑΡ ϋ ϋ 9 3 5

TABLE IV

Sterilizat.ion of C.sporogenes-labeled porcelain cylinders by

formulations of H2O2 plus acetic, glutaric, and citric acid.
5 roiroulation	pe Exposure Time Value Hin. x 20* C	Percentage of Twenty c.sporogenes-labeled cylinders sterilized

10	S% H₂O₂ plus 0.2M Acetic	2.4	20 30	100% 100
	Acid
15		4.3	20	100%
			30	100

	2.2	20	100
20	6% H2°2 Pl^G:i	30	100
	0.2 M Glutartc
	Acid
	5.0	20	• Zero
		30	zero
25
	1.9	20	zero
	8% H₂°2 Pl^Ui3	30	zero
	0.2M citric
30	Acid
	G.e	20	zero
		30	zero

AP/P/ 9 8/01341

v. ^Γ:ί

ΑΡ 00935

TABLE V

Surviving Colonies of Wet Spores of B.subtilis After Exposure to Formulations of Η2θ2 Plus Acetic Acid, Glutaric Acid, or Citric Acid.

Formulation	pH Value	Exposure Time Min. x 20’	Surviving Colonies of B.suhtilis at Dilution Factors
5X10¹	Sxio²	5X1O³	5x10 ⁴	5x10 ⁵
s% h₂o₂ plus		15		19	1	Zero	Zero
0.2 M Acetic	2.8	30	Zero	Zero	zero
Acid		€0	Zero	zero	Zero
		IS		236	121	26	1
	4.4	30	zero	Zero	zero
		60	zero	zero	Zero
B% HjOj pi*¹⁸		15	CONF -	CONF	CONF	265	70
o.2M Glutaric:	2.6	30		25	13
		60	Zero	Zero	Zero
	5.0	15	CONF	CONF	CONF	TNTC	101
		30		TNTC	206	39
		60	Zero	Zero	Zero
8» H₂O₂ pl™'		15	CONF	CONF	CONF	TNTC	198
o.2X citric	2.0	30	CONF	CONF	CONF	TNTC
		60	CONF	CONF	TNTC
	€.4	15	CONF	CONF	CONF	CONF	283
		30	CONF	CONF	CONF	CONF
		60	CONF	CONF	CONF

AP/P/ 9 8 / 0 1 3 4 1

CONF = confluent = la excess of 1000 colonies all touching togather (confluent).

TNTC = Too numerous to count = 300-1000 colonies/plate.

The following example in Table VI compares the rate of kill of B.aubtilia spores by formulations of H2O2 plus acetic, malonic, or succinic acid. The test method was wet spores of 3. aubtilia in suspension (not on carriers) . This is a quantitative test that allows comparison of formulations with more precision than a qualitative (sterile or not

AP 00935

TABLE VI

Formula

Number

D—values in Hin.*

Formula Description pH

1.	8% H₂O₂	+ 0.21J (1.2%) acetic acid.	pH	2.7	7.5
2-	8% H₂O₂	•t- 0.21J (1.2%) acetic acid,	pa	4.2	8.5
3.	8« H₂O₂	+ 0.2J1 (2.1%) malonic acid,	PH	1.8	8.5
4.	8% ^2^2	+ 0.2M (2.1%) malonic acid,	PH	3.0	7.8
S.	8% H₂O₂	+ 0.2M (2.4%) succinic acid.	PH	2.4	6.0
6.	8% R₂O₂	ι- 0.2M (2.4%) succinic acid.	PH	4.2	9.0

•The D-valu<i:i were calculated as the time to kill four log_lc of B.auistillB divided by four.

The general conclusion is that combinations of 8% H₂O₂plus acetic, malonic, or succinic acid surprisingly have about the same rate of kill of B.subtilis spores (wet) in suspension. The more acid pH values of about 2-3 were · consistently killing faster than the less acid pH values of above 4.

The tests shown in Tables VII and VIII measure the relationshi p between increasing concentrations of acetic or succinic acid plus 8% H₂O₂ and the rate of kill of wet spores of B.subtilis. The test using suspensions of wet spores of B.subtilis, and measuring surviving spores as a function of exposure time to various formulations is a quantitative test that is better able to measure small differences between formulations than the AOAC Sporicidal Test. All tests were at 20±l’C.

•AP/P/ 98/01341

Acetic Acid:

The formulations tested with acetic acid, and D-value results were as follows: .,,. . ,

·. · '·. ·· .‘./tl·’; ' · .. ·;

AP 00935

TABLE VII

	Formula Humber	Formula Description	pH Value	D-value
5	1.	B% H₂o₂ 1. oh (6%) Acetic Acid 0.5% BioTerge as-40	4.2	less than 3 Min.
10	2.	8% H₂O₂ 0.5M (3%) Acetic Acid 0.5% BioTerge AS-40	4.2	3.5 Min.
15	3 .	8% H₂O₂ 0.25M (1.5%) Acetic Acid 4.3 0.5% BioTerge AS-40	3.7S Min.
20	4.	8% ®2^2 0.125M (0*75%) Acetic	Acid 4.3	4.0 Hin.

0.5% BioTerge AS—40

BioTerge Is a 'trademark of Stepan Company and is a sodium olefin 25 sulfonate

The formulations tested with succinic acid, and D-value results were as follows in Table VIII:

30		TABLE VIII
	Formula Number	Formula Description pH Value D-value
35	1.	8% h₂o₂ less l.OM (11.8%) succinic Acid 4.3 0.5% BioTerge AS-40	than 3	Min.
40	2.	8% H₂O₂ 0.5M (5.9%) succinic Aoid 4.2 0.5% BioTerge as-40	3.5	Min.
45	3.	8« H₂C₂ 0.25M (2.95%) Succinic Acid 4.2 0.5% BioTerge as-40	3.5	Min.
50	4.	8% ®2θ2 0.125K (1-47%) succinic Acid 4-2 0.5% BioTerge AS-40	3.0	Min.

AP/P/ 9 8/ 0 1 3 4 1

I

ΑΡ υ υ 9 3 5

As demonstrated in Tables VII and VIII at equal molarities, and equal ρΣΙ values of about 4.2, there is vejy little difference between acetic acid and succinic acid to enhance spore kill In combination with 8% H₂°2 ^an<^ BioTerge AS-40.

As one covers a range from a high of 1.0H to a low of

0.125M, an eight-fold difference, the rate of spore kill changes very little from the slowest rate of about 4.0 min. to the fastest rate of about 3.0 min. The change is consistent with 1.0M acetic or succinic acid always showing a faster spore kill than lesser concentrations, but it is a very small change.

8% H₂0₂ (2.35M) plus 1% (0.17M) acetic acid, or plus 0.2M acetic acid at pH 2.5 (all of the acetic acid in the acid form), or pH - 4.3 (about half of the acetic acid in the

IS acid form, and half as sodium acetate) killed spores of

C.sporogenes and B.subtilis within 30 min. at 20±l^eC. More B.subtilis spores were killed within 15 min. at the lower pH (about 2.5) than at the higher pH (about 4.3), but complete kill happened within 30 min. for both pH values.

8% H₂0₂ plus 0.5% malonic acid or 0.5% succinic acid cooh-ch₂-cooh cooh-ch₂-ch^-cooh

Malonic Acid Succinic Acid all at pH 3.8 - 2.4 sterilized porcelain cylinders labeled with C.sporogenes within 30 min. at 20±l'C.

8% H₂0₂ Pl^us 0-2M glutaric acid (COOH-CH₂-CH₂-CH₂-COOH) was less active than succinic acid, and more active than citric acid. 8% H₂O₂ plus 0.2ig glutaric acid at pH 2.2 -2.6 killed wet B.subtilis spores within 60 min. at 20±l*c, but not within 30 min., and sterilized C.sporogenes dried onto porcelain cylinders within 30 min. at 20±l*C, pH 2.2, but not at pH 5ΣΌ (where half of the glutaric acid exists as the acid ·'····,,,*,, ....... · I . · 'and‘half exists as the sodium salt).' ' ' 8% H₂O₂plus 0.2M citric acid, a tricarboxylic acid,

COOB—CH₂—COHCOOH-CB₂—COOH / did not' kill “wet B fsubtilis ' spores ⁼ at’ all within-60 xiiin. at ^Oi'i-C'either at'pH^;2‘fo or 6.4. Similarly, 8% H₂°2 plus’όί2Μ citric acid at pH ^ri?9 or 6.6

I fr £ I 0 t 8 6 /d/dV

ΑΡ υ υ 9 3 5 could not sterilize any C. sporoyenes-labeled cylinders at 20±l’C.

The above tests lead to the following observations:

The initial testing was performed because of the similar structural chemistry between peracetic acid (CH3-COOOH) and acetic acid (CH3-COOH). The following formulations were tested: (1) 6% H₂O₂, pH 4.7, (2) 6% H₂O₂ +0.5¾ acetic acid, pH 2.7, (3) 6% Η₂θ₂ ⁺ ®«5% sodium acetate, pH 6.7, (4) 0.5% acetic acid, pH 2.8, and (5) 0.5% sodium acetate, pH 7.7. Unglazed porcelain cylinders labeled with approx. 10⁶ dry spores of Clostridium sporogrenes according to the methods of the AOAC Sporicidal Test 966.04 were exposed to these above five formulations for 30 min. at 20+l*C. Of a total of 20 spore-labe.Led cylinders, 18 were sterilized when exposed to 6% H₂O₂ + 0.5% acetic acid (Formula #2 above). None (zero) of 20 were sterilized when similarly exposed to the other formulas.

Two cylinders from a total of 20 tested were not sterilized by formula #2 above. Next tested were increased concentrations of H₂O2 ^anc* acetic acid for ability to sterilize dry cylinders labeled with C.sporogenes. 8% H₂O₂ plus 2% acetic acid sterilized within 20 min. at 20±l°C, 8% H₂O₂ pl^us 1% acetic acid, and also 8% H₂0₂ plus 0.5% acetic acid sterilized within 30 min. at 20±l’C.

The above tests were then expanded to determine if other weak di- or poly carboxylic acids could act synergisiically with H₂C>2 rapid sporicidal activity. The dicarboxylic acids, malonic (COOH-CH₂-COQH), and succinic (COOH-CH₂-CH₂COQH) were tested. 8% H₂O₂ plus 1% acetic acid, pH 2.5, sterilized within 3Q min. at 20±l*C. 8% H₂0₂ plus 1% malonic acid, .pH 1.8,. sterilized .17 _rcylinders put of 20 within 30 min. at 20il’C, and 8% H₂O₂ plus„0.5% succinic acid.pH :2.4, sterilized 19 cylinders out of ..20...within 30 min. at 20±l’C. The .test .was C.sporogenes an porcelain cylinders.

.Η₂θ2 plus ..the weak carboxylic ..acids produce _;a formula with acidic pH values of 2-3. However, the carboxylic acids can act aa buffers by taking them up to a pH value where half

AP/P/ 9 8 / 0 1 3 4 1

AP u u 9 3 5 of the molecules are in the acid form (CH3-COOH) and half of the molecules are the conjugate base (CH3-COO^-) . These higher pH values (pH 4-5) might be more compatible with materials than the lower pH values. 8% H₂O₂ pl^us θ·2 M citric acid (a tricarboxylic acid) did not sterilize C.sporogenes-labeled cylinders at pH 1.9 or 6.6. 8% H2O2 plus 0.2 M glutaric acid (COOH-CH₂“CH2-CH₂-COOH). did sterilize within 30 min. at 20±l^eC at pH 2.2, but not at pH 5.0. 0% H₂O₂ plus 0.2 M succinic acid (COOH-CH₂-CH₂-COOH) sterilized within 30 min. at 2041’C at both pH 1.8 and 3.0.

8% H₂O₂ plus 0.2 M acetic acid sterilized within 30 min. at 20±l’C at both pH 2-7 and 4.2. These studies were all against C.sporogenes-labeled cylinders.

Studies have been performed using these formulations against Bacillus subtilis spores both in the form of dry spores carried on porcelain cylinders, or wet spores in suspension. The results against B.subtilis are consistent with results against C.sporogenes as follows: 8% H₂O₂ plus 0.2 M citric acid at pH 2.0 or 6.4 did not kill wet spores of B.subtilis within 60 min. at 20±l’C. 8% H₂0₂ plus 0.2 H acetic acid (pH 2.7 or pH 4.2) killed wet or dry B.subtilis within 30 min. at 20±l°C. 8% H₂0₂ + 0.2 M malonic killed wet spores of B.subtilis faster at pH 1.8 than at pH 3.0- 8%

H₂O₂ + 0.2 M succinic acid at pH 2.4 killed wet or dry spores of B.subtil is, but was less effective at pH 4.2. 8% H₂O₂ plus 0.2 M glutaric acid was more effective against wet spores of B.subtilis at pH 2.6 than at pH 5.0. The specific test results are described below.

This example compares the rate of kill of B. subtilis spores by iormulations of H₂O₂ plus acetic, malonic, or succinic acid. The test method utilized wet spores of B.subtilis in suspension (not on carriers). This is a'' quantitative test 'that allows comparison of formulations with more precision than a. qualitative (sterile or not sterile) ¹ *- , \ ‘s' ' “ ' ' ?? ι · · r,_t. ₍ ·» · · - ,, , . I . ·/ /··, test such as the AOAC Sporicidal Test. The starting^ number of cells of B.subtilis was very highat about 3 . lklO⁸’cellsi

AP/P/ 9 8 / 0 1 3 4 1

AP u U 9 3 5

It required about 60 min. of exposure time at 20±l^eC to kill, all of these cells.

The results were as follows:

TABLE IX

Formula

Dumber

Formula Description pH D-values in Min.

10	1.	8«	h₂o·,
	2.	8%	h₂o-,
	3.	8%	«2°;:
	4 .	B%
	5.	8%
15	6.	8%	^h2°;>

+ 0.2M (1.2%) + 0.2^ (1.2%) + 0.2M (2.1%) + 0.2M (2.1%) + 0.2M (2.4%) + 0.2M (2.4%)

The D-valuefi were divided by :: our.

acetic acid, acetic acid, malonic acid, malonic acid, succinic acid, succinic acid,

pH	2.7	7.5
PH	4.2	8.5
PH	1-8	8.5
PH	3.0	7.8
PH	2.4	6.0
PH	4.2	9.0

kill four log₁₀ of B.subtllis calculated as the time to

The general conclusion is that combinations of 8% H2O2 plus acetic, malonic, or succinic acid have about the same rate of kill of B.subtilis spores (wet) in suspension. The more acid pH values of about 2-3 were consistently killing faster than the less acid pH values of about 4.

Next, three formulations of 8% H2°2 (^a 2.00 succinic acid formulation, a pH 4.35 succinic acid formulation, and a pH 4 .23 acetic acid formulation) were placed into plastic trays with loose-fitting plastic lids. Various combinations of stainless steel instruments, endoscope parts, and respiratory care equipment were soaked in the formulations for fourteen days at ambient temperature (22±2’C). Two marketed disinfectants (2% alkaline glutaraldehyde, and 0.25% quaternary ammonium compounds in 15% isopropanol) were also ueed in the study for comparison.

After- fourteen days of continuous soaking in the H2O2 formulations, quality Sklarlite® stainless steel instruments appeared unchanged. Less expensive, poorly-plated instruments became mildly tarnished by the three H2O2 formulations. By comparison, the .quality Skarlite® instruments had become slightly rusted by 2% alkaline gluteraldehyde and extremely rusted by the alcohol

AP/P/ 9 8 / 0 1 3 4 1

AP 00935 h₂o disinfectant- With one exception, the endoscope parts and respiratory care equipment appeared unchanged by any of the ^h2°2 ⁺ carboxylic acid formulations. The details of the test are reported below.

The study of this example was limited to visual observations of materials compatibility with the formulations as previously described. In particular, the formulations used were:

Formulation #1 8% H₂O₂

0.5 M Acetic Acid 0.25% Bio-Terge AS-4 0 detergent 0.25 M Na03

Prepared with USP purified deionized pH 4.23

Formulation #2

8% H₂0₂

0.5 M Succinic Acid

0.25% Bio-Terge AS-40 detergent 0.5 M NaOH

Prepared with USP purified deionized pH 4.35 25

Formulation #3

8% H₂O₂

0.5 M Succinic Acid 0.25% Bio-Terge AS-40 detergent 30 Prepared with USP purified deionized pH 2.00

The materials were soaked in the above test formulas or in: .. ., .... .......

₃₅ ·- - · · . · · · .·· ·· 0.25% quaternary ammonium chloride in_;15% isopropanol, or 2% alkaline glutaraldehyde. .

h₂o h₂o dr>

X £

<

AP 00935

The items soaked were:

Eight Carabro plastic trays with loose-fitting plastic lids;

Five Sklarlite® stainless steel Halsted Mosq. STR 5

Hemostats. Sklar Hospital Catalog #23-2105. New?

Three pair of inexpensive scissors, poorly plated, but otherwise in good condition with no tarnish;

One set of respiratory care equipment:

a Y” plastic connector a face mask an endotracheal tube a section of a blue latex breathing bag

Two sets of endoscope parts, the first being:

insertion tube, bending rubber, biopsy channel, pliable »

1/3 id connector, hard « 1/2 id connector, and hard » 1/2 di am. cap.

The second set was an insertion tube, bending rubber, biopsy channel, hard « 1/2 id connector, hard »= 1/2” diem, cap, and hard » 1/2 diam. cap with stainless steel opening.

All parts were new or in good condition at the start.

Two hundred ml of disinfectant and various instruments, parts, and equipment were placed into eight plastic trays. The traye were covered and left at ambient temperature (22± 2’C) for fourteen days. Observations were made at various intervals throughout the fourteen day time. The results are reported in Table X, below.

Results:

TABKg X

Observations of Materials Compatibility Exposure Thue to Disinfectant

Die infect ant instrument Day 2 Day 3 Day € Day. 9 Day 14

2% Alkaline ' Henoetate N.C. ~ N.'c? '^: N.C. ' ^; alight “slight glutaraldehyde rust in rust in hinge hinge

AP/P/18/01341

AP 00935

0.25% quaternary ammonium chloride in 15% iaoproponol	Hemostata	N.C.	2-3 mm rust spot in hinge	major rust in hinge	major rust in hinge	major rust in hinge
Formulation #1
0% H₂O₂ 0.5 ;4	Hemostata	N.C.	N.C.	N.C.	N.C.	N.C.
Acetic Acid					-
Q.25% Bio-	Scissors	N.C.	N.C.	Mild	Tarnish	Tarnish
Terge AS-40				tarnish	on	on
0.25M NaOH					'handle	handle
pH = 4.23					&	£
					hinges	hinges
Formulation 13
	Hemoatats	R.C.	N.C.	N.C.	N.C.	N.C.

0.5 M succinic Acid

0.25% BioTerge AS-40 pH = 2.00	Scissors	N.C.	N.C.	Mild tarnish	Tarnish on handle & hinges	Tarnieh on handle & hinges
Formulation f2
8% H₂O₂	Hemostata	N.C.	N.C.	N.C.	N.C.	N.C.

0.5 M Succinic Acid

AP/P/ 9 8 / 0 1 3 4 1

0.25% Bio-	scissors	N.C.	slight	Mild	Tarnish	Tarnish
Terge as-40	-		tarnish	tarnish	on	on
0.5 M NaOH			in		handle	handle
pH = 4.35			hinge		&	&
					hinges	hinges

Formulation #2

8« H₂O₂	Y	N.C.	N.C.	N.C.	N.C.	N.C
0.5 M Sueeinic	Connector	N.C.	N.C.	N.C.	N.C.	N.C
Aaid	Face Mask
0.25% Bia-	Endo-	N.C.	N.C.	N.C.	N.C.	N.C
Tergs AS-40	tracheal
0.5 M NaOH	Tube
pH - 4.35	Breathing . Tube	N.C.	N.C.	N.C.	N.C.	N.C

ΑΡ υύ93 5

Formulation 8% H2°2	insertion Tube	N.C.	N.C.	N.C.	N.C.	N.C.
0.5 M succinicAcid	Biopsy channel	N.C.	N.C.	N.C.	N.C.	N.C.
0.25% BioTarge AS—40	Bending Rubber	N.C.	N.C.	N.C.	N.C.	N.C.
pH = 2.00	Pliable connector	N.C.	N.C.	N.C.	N.C.	Broke into small pieces
	Hard Connector	N.C.	N.C.	N.C.	N.C.	N.C.
	Hard cap	N.C.	N.C.	N.C.	N.C.	N.C.

Formulation
8% HjOj	insertion	N.C.	N.C.	N.C.	N.C.	N.C.
0.5 M succinic	Tube
Acid	Biopsy	N.C.	N.C.	N.C.	N.C.	N.C.
0.25% Bio-	channel
Terge AS-40	Bending	N.C.	N.C.	N.C.	N.C.	N.C.
0.5 M NaOH	Rubber
pH - 4.35	Hard cap	N.C-	N.C.	N.C.	N.C.	N.C.
	Hard	N.C.	N.C.	N.C.	N.C.	N.C.
	connector
	Hard Cap	N.C.	N.C.	N.C.	N.C.	N.C.

AP/P/ 9 8 / 0 1 3 4 1 with stainless steel opening

N.C. = No Change

As seen from data in Table X, formulations 1, 2 and 3 did not cause any apparent changes to the quality Sklarlite® instruments. The formulations did cause some tarnishing of the poorly-plated instruments. The pH 2.00 8% H2O2, succinic acid formulation caused more tarnishing than the other two formulations.

In comparison, 2% alkaline gluteraldehyde caused minor rusting of the quality Sklarlite® hemostats, and 0.25% quaternary ammonium chloride in 15% isopropanol caused major rusting of the Sklarlite® hemostats.

The pB 2.00, 8% H2O2, succinio acid formulation did cause major disintegration of one piece, the pliable endoscope connector, which fell apart when squeezed slightly. It was not known whether this aberation was caused by the nature of the elastomer of this single part or not. However, ^s' AP ο u 9 ό 5 no other parts during testing showed any damage by succinic acid compositions.

Formulations 2 and 3 did not cause any apparent change to the other endoscope parts. Formulation 2 did not cause any apparent, change to the respiratory care equipment.

While not wishing to be bound by a theory of why the invention works, the data in the above examples demonstrates an apparent reaction and a synergistic relationship between hydrogen pel oxide specifically and certain of the described carboxylic acids. It probably extends to peroxides in general that, release hydroxyl free radicals that together cause rapid kill of bacterial spores and all other microbes at ambient (approximately 18^eC-24^eC) temperatures. There is no need for heating, and moreover the kill is generally accomplished within 30 min. It also suggests that a reaction product may be formed in situ which could be isolated and itself usee, as the quick acting sterilant, and thus the invention contemplates such an embodiment as being within its scope.

It therefore can be seen that the invention accomplishes all of its stated objectives.

Claims

What is claimed is:

AP UU935

Hilling now particularly des<·riht?d and •jsccriained niy/our said inven:!<·Τ v hut manner the same is m be ρ,.·>

< Uv.’wilUC tlli.lt What i. v,\‘ ckliiB is

1. A low odor, aqueous quick acting room temperature disinfecting and/or sterilization solution having a pH within

5 the range cf from about 2.0 to about 6.0, comprising: from about 1% tc about 30% by weight of a peroxide; and from about, 1% to about 30% by weight of water soluble organic acid or salt form thereof, selected from the group consisting of C3 or higher mono carboxylic acids and di- or poly, carboxylic

10 acids of up to C^2 chain length, or mixtures thereof.
2. The aeneous disinfecting and/or sterilizing solutions of v— claim 1 wherein the water soluble organic acid or salt form thereof is selected from the group consisting of malonic

15 acxd, and succinic acid, or mixtures thereof.
3. An aqueous disinfecting and/or sterilizing solution of QO claim 2 wherein the peroxide has a concentration of from .

about 1.0% by weight to about 12% by weight.

20 £
4. An aqueous disinfecting and/or sterilization solution of < claim 1 wherein the peroxide capable of releasing hydroxyl free radicals is selected from the group consisting of hydrogen peroxide, alkyl peroxides, aryl peroxides, ozonides,

25 and alkylidine peroxides.
5. A low odor aqueous quick acting, relatively non-toxic room temperature disinfecting and/or sterilization solution having a pH within the range of from about 2.0 to about 6.0,

30 comprising : from about 1.0% to about 30% by weight of a peroxide capable of releasing hydroxyl free radicals; from about 1.0% to about 30% by weight of a water soluble organic acid or a salt form thereof, selected from the group consisting of C3 or higher mono and dicarboxylic acids of up

35 to C32 chain length; and from about 0.1% to about 1.0% by weight of a peroxide and organic acid compatible anionic or nonionic surfactant.

AP 00935
6. The aqueous disinfecting and/or sterilizing solution of claim 5 wherein the water soluble organic acid or salt form thereof is selected from the group consisting of malonic acid

5 and succinic acid or mixtures thereof.
7. A process of quick action room temperature disinfecting of medical instruments without damaging the instruments, comprising: contacting at room temperature the instruments

10 for a sterilizing effective amount of time with an odor-free aqueous disinfecting solution having a pH within the range of from about 2.0 to about 6.0 which consists essentially of from about 1.0% by weight to about 30.0% by weight of hydrogen peroxide and from about 1.0% by weight to 30.0% by

IS weight of a low odor water soluble organic acid or a salt form thereof selected from the group consisting of malonic and succinic acids or mixtures thereof.
8. The piocess of claim 7 wherein the organic acid is succinic acid.

TO o

co
9. The process of claim 7 wherein the aqueous disinfecting solution contains a peroxide and organic acid compatible surfactant.