US2987435A - Germicidal compositions - Google Patents

Description

assmss Patented June 6, 1961 2,987,435 GERMICIDAL COMPOSITIONS Thomas Gwyn Davies, Vaucluse, New South Wales, Australia, and Doreen Lois Wedderburn, London, England, assignors to Lever Brothers Company, New York, N.Y., a corporation of Maine No Drawing. Filed Aug. 6, 1958, Ser. No. "753,419 Claims priority, application Great Britain Aug. 8, 1957 9 Claims. (Cl. 16718) This invention relates to germicidal compositions which are also bleaching agents.

Quaternary ammonium salts are widely used for their germicidal properties and are especially valuable not only because they show high germicidal activity against both gram positive and gram negative organisms in dilute solution, but also because of their stability, lack of odor and lack of toxicity. When a substrate material is treated with a solution of a quaternary salt and the material is then washed with water, the. material generally retains a proportion of the germicidal activity of-the quaternary salt against gram positive organisms, but retains very little, if any, activity against gram negative organisms: the gram positive germicidal properties can thus be said to be substantive to the substrate material, while the gram negative germicidal properties are not substantive.

It has now been discovered that when a quaternary ammonium salt is incorporated in a hypochlorite solution that the substantive gram positive germicidal proper-v ties are enhanced synergistically and the formerly nonsubstantive gram negative germicidal properties become substantive and also are synergistically enhanced. Substantive is used in the normal sense to mean that the quaternary ammonium compounds and their germicidal properties are substantially permanently attached to the material. It has been found that when proteinaceous and cellulosic materials are treated with a quaternary ammonium salt in conjunction with an aqueous sodium hypochlorite solution, for example, they retain after washing synergistically better germicidal properties than when a quaternary ammonium salt is used alone. Moreover, the sodium hypochlorite retains its bleaching properties.

The compositions of the invention accordingly comprise a hypochlorite solution in which is incorporated a germicidal qua-ternary ammonium salt.

The hypochlorite solution will normally be aqueous sodium hypochlorite solution, though other hypochlorites, for instance potassium and calcium hypochlorites' or mixtures thereof, can also be used. Commercial hypochlorite bleaching solutionsare suitable.

wQuaternary ammonium salts which are suitable are those which have a substantial germicidal activity, for example benzalkonium chloride (which is a mixture of alkyldimethylbenzylammonium chlorides in which the allgyls range from C l-1 to C H cetyl pyridinium bromide, cetyl trimethylammonium chloride and fi-(p-tertoctylphenoxyethyl) diethyl benzylammonium chloride. Other substances which can be used are lauryl pyridinium chloride and dodecylbenzyltrimethylammonium chloride. The compositions of the invention are conveniently obtained by adding the quaternary ammonium salt, as such or in aqueous solution, to an aqueous hypochlorite solution, and mixing the components together. Preferably the materialsadde'd are such that the composition obtained' contains the equivalent of at least 0.1% by weight of available chlorine and 0.01% quaternaryammonium salt. Very suitable are composi-' tions based on sodium hypochlorite solution containing from :l to by weight of available chlorine. Preferably from 0.05 lto 20 parts of quaternary ammonium salt are incorporated for each part by weight of chlorine, It is'convenient to prepare a composition which is relatively by weight of concentrated, and which can be diluted with water before use. An aqueous sodium hypochlorite solution containing 0.25 to 1.5%, for instance 0.5 or 1%, by weight of available chlorine to which is added a suitable amount of quaternary ammonium salt, for instance 5% (or 2.5 to 7.5%) of the salt by weight of the solution is very suitable for use as a germicidal bleaching agent after 40 told dilution. The relative proportions of hypochlorite and quaternary ammonium salt which are suitable in any given instance will depend upon the particular use to which the composition is to be put, and accordingly upon the extent of bleaching and germicidal properties which are desired.

When a quaternary ammonium salt is added to a relatively concentrated hypochlorite solution, there is usually some form of phase separation: a cloudy liquid or emulsion may be obtained which on standing may separate into two layers; alternatively, a crystalline precipitate may be thrown down after standing for some time. This may be due to complex formation between the ingredients of the composition. The degree of inhomogeneity will depend not only on the concentrations and the nature of the ingredients used, but also on the age of the composition. Unwanted inhomogeneity can be avoided by using suitable concentrations of the ingredients, or in some cases by adding dispersing agents.

The invention also includes a process in which materials are treated by contacting them with a composition of the invention. The process is particularly suitable for use with keratinous fibers, for instance human haid and wool, and with cellulosic fibers. It has further been discovered that the synergistically enhanced substantive germicidal properties can be given to the material by bringing the two components of the compositions of the invention (that is, the hypochlorite and the quaternary ammonium salt) together on the material itself. Thus the hypochlorite and the quaternary ammonium salt can be used successively to treat the material to which the properties are to be given. For instance the material can betreated first wit han aqueous hypochlorite solution containing 0.1% (or 0.5% or 1%) available chlorine and then with a 0.02% aqueous benzalkonium chloride solu tion. Such processes are also within the scope of the invention.

The invention is illustrated by the following examples.

EXAMPLE 1 'To 10 g. of an aqueous sodium hypochlorite solution containing 5% by weight of available chlorine was addedby weight aqueous solution of benz' alkonium chloride (a benzyl'dimethyl alkylammonium '1 g. of a 50% chloride in which the alkyl group is a long'chain alkyl group having an The composition obtained on shaking the two components together was a cloudy liquid containing 4.5% by weight of available chlorine and 4.5% by weight of benzalkom'um chloride, representing a composition according to the invention.

The synergistically enhanced substantive germicidal properties of the composition towards cotton poplin fabric was tested as follows. A strip of a cotton poplin (0.5 g.)

' was immersed in the composition 100 cc.) for 5 minutes,

containing 5% available-chlorine and washed and dried. in the same way,

removed and washed 3 times with distilled water cc.), and dried. Three 1 cm. squares were cut from the' strip and placed one each on the surface of three agar plates seeded respectively with the organisms Ps. fluorescens, Staph. albus andStreptococcus bovis.

(The first of these organisms is gram negative and the others are gram positive.) Simultaneously squares of poplin treated by immersion in aqueous sodium hypochlorite solution and also squares similarly treated with average length of 13 carbon atoms);

Zone of inhibition (mm.)

Treatment of poplin 1 Ps. fluo- Staph. Strep.

T8SC6TLS albus bovis Hypochlorite "l -i i 1 0.5 Ben'zalkonium chloride 0 6 3 Hypochlorite and benzalko um c oride 6 11 8 The synergistically enhanced substantive germicidal properties of the composition containing hypochlorite and benzalkonium chloride are clearly shown.

The composition was further tested for its activity on dilution by treatment of cotton poplin in the same way as described above, but with '5 fold, 10 fold, 20 fold and 40 fold dilutions of the composition with distilled water, using the organisms Ps. fluorescens and Staph. albus. Similar tests were carried out with corresponding dilutions of benzalkonium chloride and sodium hypochlorite separately. The zone tests in each instance showed a synergistic effect between the two components in the composition, giving synergistic residual germicidal activity against the two organisms.

EXAMBLE 2 Test A The synergistically enhanced substantive germicidal properties of this composition towards cotton poplin was tested using the procedure of Example 1. The results were as follows:

Distance of inhibition (mm.)

Treatment of poplin r Ps. fluo- Staph. Strep. Tescens albux bovzs Hypochlorite 1 o. t 0 Benzalkonium chloride 0 6 3 Hypochlorite and benzalkoninrn chloride 6 10 9 Test B The synergi'stically enhanced substantive germicidal properties of the composition towards hair was next tested by the following procedure. A l g. sampleof human hair was immersed for minutes in 100 cc. of a solution prepared by diluting 10 cc. of the composition with water (that is, at 10 fold dilution); The hair was then removed, washed three times 'with distilled .water and dried. Different quantities of the treated hair (1, 25, 50, 100 and 150 mg.) were 'theuWeighed out and placed in bottles containing 20 cc. of Rogosa broth which had been inoculated with '1 cc. of aturbid culture of L'acto bacillus casei, a gram positive lactic acid producing organism; the broth containinghair wasjin'cubated at 37 C. for 24'hour1sand the pH'or" the broth then measured. i

Further samples of hair were prepared as described above but using difierent treating solutions, namely a solution prepared by diluting 20 cc. of the composition to cc. with distilled water (that is, at 5 fold dilution); solutions prepared by diluting 10 cc. and 20 cc. respectively of an aqueous solution of sodium hypochlorite containing 5% by weight of available chlorine to 100 cc., and solutions prepared by diluting 10 cc. and 20 cc. respectively of an aqueous solution containing 0.5 by weight of benzalkonium' chloride to 100. cc". These samples were added in weighed amounts to tubes of Rogosa'broth, incubated and the pH of the, broth measured after 24 hours as before. Control experiments in which no hair was placed in the inoculated broth or in which the inoculated broth was refrigerated were also carried out. These were accordingly upper and lower limit controls. The results were as follows:

pH of incubated broth according to-amount of hair added Treatment of hair (mg) (At 10 fold dilution):

Hypochlorite and benzalkonium chloride 5.15 5. 30 5. 35 5. 40 5. 50 Hypochlorite alone 5. 20 5. 20 Benzalkonium chloride alone 5; 15 5'. 20 5. 25 5. 25 5. 25 (At 5fo1d dilution):

Hypochlorite and benzalkonium chl0ride 5.15 5. 32 6. 47 5. 55 5.65 Hypochlorite alone 5. 20 Benzalkonium chloride a1 5. 25 5. 25 5.25 5. 30

The incubated control broth had a pH of 5.07, while the refrigerated control had a pH of 5.80. p

The extent of reduction of acidity, or increase of, pH, in the broth containing treated hair is a measure of the reduction in activity, and hence in, growth, of the Lactobacillus, and is thus a measure of the germicidal properties retained by the treated hair. The superior results obtained with treatment of hair using the composition of the invention as compared with its separate ingredients are clearly shown.

' Test C In another test, the synergistically enhanced substantive germicidal activity of the composition towards cotton poplin fabric was compared with that of benzalkonium chloride alone using the following procedure. Cotton poplin was immersed for 5 minutes in'the composition containing 5% of available chlorine and 05% of benzalkonium chloride further diluted 10 fold with distilled water; then removed, washed well with distilled water and dried.- -Another sample of cotton poplin was similarly treated except that it was immersed in 0.5% benzalkonium chloride solution diluted 10 told without any hypochlorite. The two copies of treated poplin were cut up and weighed out into two sets of bottles containing 20 cc. of nutrient broth, in varying amounts (1, 5, '10 and 50 mg. respec tively). A bottle containing broth with no added poplin and one with unseeded broth were prepared as controls.

The bottles were each seeded with 0.1 odor-Staph. albus and incubated at 37 C. for 24 hours. "The turbidity ofeach broth sample was then determined using a nephelorneter, and gave an estimate of the relative numbers of bacteria present and hence of the germicidal activity retainedby the treated fabric. The results were as follows.

EXAMPLE 3 ried out using 10 fold and 100 fold dilutions with distilled water for treatment of the poplin. Similar tests were conducted using 5% aqueous benzalkonium chloride solution without any hypochlon'te. The zones of inhibition were measured as in Example 1. I

Organism Staph. albus I Ps. fluorescem Dilutlon.

Nil I 10 fold I100 fold Nil Distance of inhibition (mm) Composition used:

Quaternary (5%) with no hypochlorite 9 8 5. 5

Quaternary 4.5% 5116 E551 ehlorite:

It Will be seen that even when as little as one part by weight of available chlorine was present to ten parts by EXAMPLE 4 This example illustrates four compositions of the inven 'on containing difl erent quaternary ammonium salts, and compares their synergistically enhanced substantive germicidal activity with that of each of their ingredients, against four different organisms. .The quaternary ammonium salts employed were (A) benzalkonium chloride, (B) 13- (p-tert.octylphenoxyethyl) diethyl benzylammonium chloride, (C) cetyl pyridinium bromide, and (D) cetyl trimethylammonium chloride. The compositions were obtained by adding 4% by weight of quaternary ammonium salt to a sodium hypochlorite solution containing by weight of available chlorine: a cloudy solution or emulsion was obtained in each case, except with cetyl pyridinium bromide, which gave a clear yellow solution.

Cotton poplin squares were treated using the procedure of Example 1 and employing the dilferent compositions; agar plates seeded with the organisms Staph. albus, Strep. bovis, B. c011 and Ps. fluorescens were used (the first two of these are gram positive and the last two gram negative). Squares of poplin were treated with a sodium hypochlorite solution containing 5% by weight of available chlorine, with each of the compositions, and with aqueous 4% by weight solutions of each of the quaternary ammonium salts alone. The results were as follows.

Distance of inhibition (mm.) Treatment Staph. Strep. 8. e011 Ps. flualbus bouts orescem Hypoehlorite alone 1 1 1 1 Quaternary salt (A) with hypoehlo- 13 7 2 8 rite alone. 6 3 0 0 Quaternary salt (B) with hypochlo- 11 6 2 2 rite alone. 1 6 1 0 0 Quaternary salt (0) with hypochlo- 10 8 10 5 rite alone. 5 4 0 0 Quaternary salt (D) with hypochlo- 5 4 3 2 rite alone. 2.5 1 0 0 EXAMPLE 5, p

The synergism between benzalkonium chloride (B.A.C.) and pure 10% sodium hypochlorite solution and also between'cetyl trimethyl ammonium bromide, Cetavlon, calculated as C H (CH NBr and pure 10% sodium hypochlorite solution were investigated using the following procedure.

A piece of cotton poplin (0.5 g.) was shaken in 100 cc. of test solution for two minutes, washed three times with 100 cc. distilled water and dried overnight. Squares (1 cm.) of the treated poplin were then laid on plates interfor 24 hours at 37 C.

Test solutions used contained '(a) quaternary salt, (b) hypochlorite, (c)- quaternary and hypochlorite, and the results are given in the following table.

Zones of Inhibition in Millimeters Pseudo- Staph. Strep. monas B. al us bovis fluorescolt lia e 2 g 9 2. 5 1 0 NaOOl. 2.5 0 0 0 0 L25 15 11 2.5 2.5 NaOC-l 10 1 0 1 0 getggllom- 12 7 4 0 0 a a. +Oetavlon +5 12 12 1 4 aOOL. 5 0 0 0 0 Oetggllonu 2 g 5 4 0 0 +Cetavlon +2.5 10 11 1 4 Na0OI 2.5 0 0 0 0 oet ng on 2. 2 6 5 0 0 a +Oetavlon +1.25 8 10 1 2 The results show conclusively a synergistic effect. This fibrous materials as well as to bleach said materials. The

1. A process of cleaning and disinfecting a material which comprises the steps of contacting said material with 7 a solution of sodium hypochlorite containing from 0.45% to about 5% of available chlorine and thereafter contacting said material with an aqueous solution containing from about 0.05% to about 5.0% by weight of benzalkonium chloride.

2. The process of cleaning and disinfecting a material wherein the material is contacted with a germicidal composition comprising sodium hypochlorite and benzalkonium chloride, the sodium hypochlorite being present in an amount suflicient to provide from about 0.45% to about 5.0% by weight of available chlorine, and the benz alkoniurn chloride being present in an amount ranging from about 0.5%, to about 5.0% by weight.

3. A process as set forth in claim 2, wherein the material is a keratinous fiber.

4. A process as set forth in claim 2, wherein'the material is a cellulosic'fiber.

5. A germicidal composition comprising sodium hypochlorite and benzalkonium chloride, the sodium hypochlorite providing from about 0.45% to about 5 .0% by weight of available chlorine, and said benzalkonium chloride being present in an amount ranging from about 0.5% to about 5.0% byweight.

6. A germicidal composition comprising sodium hypochl-orite and cetyl trimethyl ammonium bromide wherein the weight ratio of the cetyl trimethyl ammonium bromide to the available chlorine from the sodium hypochlorite is approximately 1:1.

7. -A gernucidal composition comprisin'g'sodium hypo 8 chlorite Iand '18-(p tertoctylphenoxyethyl) diethyl benzylammonium chloride'wherein the weight ratio of the henzylammonium chloride wherein the weightratiopf the benzyl'ammonium chlorideto the availablechlorine from the sodium hypochloriteisapproximately 4:5.

8. A germicidal composition comprising sodium hypochlorite and cetyl pyridinium bnomide wherein the weight ratio of the cetyl pyridinium bromide to the available chlorine from the sodium hypochlorite is approximately 4:5.

9. A germicidal composition comprising sodium hypochlorite and cetyl trimethyl ammonium chloride wherein the weight ratio of the cetyl trimethyl ammonium chlorride to the available chlorine from the hypochlorite is approximately 4:5.

References Cited in the file of thispatent UNITED STATES PATENTS [Halvorson Nov. 25, 1941 Kalusdian May 25, 1943 OTHER REFERENCES Soap Journal, September 1956, vol. 22, p. 58.

UNiTED STATQS PATENT OFFICE oE'rEieM or Patent No. 2,987,435 June 6,

Thomas Gwyn Davies etall certified that error appears in the above numbered pat- It is hereby the said Letters Patent, should read as ent requiring correction and that corrected below Column 2 line 30, for haid" read hair line 40 for "wit han" read with an column 8, lines 3 and 4 strike out "wherein the weight ratio of the benzylammonium choride".

(SEAL) Attest:

DAVID L. LADD Commissioner of Patents ERNEST W. SWIDER Attesting Officer USCOMM-DC" UN iTED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 2,987,435 June 6 1961 i Thomas Gwyn Davies et a1 error appears in the above numbered pat- It is hereby certified Chat t'bers Patent. should read as ent requiring correction and that the said Le "corrected below.

line 30, for "haid" read hair line 40,

column 8, lines 3 and 4,

of the benzylammonium Column 2 for "wit han" read with an strike out "wherein the weight ratio choride".

(SEAL) Attest:

ERNEST W. SWIDER Attesting Officer DAVID L. LADD Commissioner of Patents USCOMM-DC-

Claims (1)

1. A PROCESS OF CLEANING AND DISINFECTING A MATERIAL WHICH COMPRISES THE STEPS OF CONTACTING SAID MATERIAL WITH A SOLUTION OF SODIUM HYPOCHLORITE CONTAINING FROM 0.45% TO ABOUT 5% OF AVAILABLE CHLORINE AND THEREAFTER CONTACTING SAID MATERIAL WITH AN AQUEOUS SOLUTION CONTAINING FROM ABOUT 0.05% TO ABOUT 5.0% BY WEIGHT OF BENZALKONIUM CHLORIDE.