HK1068766B

HK1068766B - Preservative blends containing quaternary ammonium compounds

Info

Publication number: HK1068766B
Application number: HK05101553.2A
Authority: HK
Inventors: Patrick Jay Lutz
Original assignee: Lonza Inc.
Priority date: 2001-03-01
Filing date: 2002-02-28
Publication date: 2007-01-12

Description

Preservative mixtures containing quaternary ammonium compounds

This application claims the rights of U.S. provisional application No. 60/279,082, filed 3/1/2001 and U.S. provisional application No. 60/345,878, filed 10/19/2001, which are both incorporated herein by reference.

Field of the invention

The present invention relates to an antimicrobial composition comprising: (a) (ii) a quaternary ammonium compound, (ii) a polymeric quaternary ammonium compound, or (iii) mixtures thereof and (b) (i) a cyclic or acyclic keto acid or salt thereof, (ii) an aromatic carboxylic acid or salt thereof, or (iii) mixtures thereof.

Background of the invention

Many quatemized compounds (e.g., benzethonium chloride) are known to be effective as antimicrobials and preservatives. However, benzethonium chloride and many other quaternary ammonium compounds are expensive. In addition, when quaternary ammonium compounds are incorporated into anionic formulations, their efficacy will generally be reduced. Accordingly, there is a continuing need to improve antimicrobial and preservative compositions containing low concentrations of quaternary ammonium compounds and maintain their efficacy in anionic formulations.

Summary of the invention

Applicants have discovered that keto acids, aromatic carboxylic acids, and salts thereof synergistically enhance the performance of certain quaternary ammonium biocides. Applicants have also found that mixtures comprising at least one of these quaternary ammonium biocides and a keto acid, an aromatic carboxylic acid, a salt thereof, or mixtures thereof are active in anionic formulations, although these quaternary ammonium biocides are often inactive in anionic formulations.

The present invention provides a composition comprising:

(a) (i) has the formula N⁺R¹R²R³R⁴X^-The quaternary ammonium biocide of (1), wherein R¹And R²Independently unsubstituted or hydroxy-substituted straight-chain or branched C₁-C₄Alkyl, - (CH)₂CH₂O)_mCH₂CH₂OH or- (CH)₂CHCH₃O)_mCH₂CHCH₃OH (wherein m is 1 to 10); r³Is substituted or unsubstituted benzyl, ethylbenzyl, methylnaphthyl or straight-chain or branched C₁-C₂₂An alkyl group; r⁴is-R⁵(O)_n(C₆H₅)R⁶(wherein n is 0 or 1); r⁵Is substituted or unsubstituted C₁-C₈Alkyl or C₁-C₈An alkoxyalkyl group; r⁶Is hydrogen or substituted or unsubstituted,Straight-chain or branched C₁-C₁₂An alkyl group; and X^-Is an anion such as chloride, acetate, borate, propionate, carbonate, bicarbonate or hydroxide,

(ii) polymeric quaternary ammonium biocides, or

(iii) Mixtures thereof; and

(b) (i) a keto acid or salt thereof,

(ii) aromatic carboxylic acid or salt thereof, or

(iii) Mixtures thereof.

The keto acid is preferably a cyclic keto acid. The mixture has synergistic effect.

Another embodiment of the present invention is a method of inhibiting the growth of microorganisms on a substrate by using an antimicrobially or preservative effective amount of a composition of the present invention.

Detailed description of the invention

The term "substituted" as used herein, unless otherwise indicated, includes, but is not limited to, at least one of the following substituents: c₁-C₁₂Alkyl (e.g. C)₁-C₄Alkyl), halogen (e.g., chlorine), nitro, and hydroxyl.

The term "biocide" includes, but is not limited to, bactericides, fungicides, insecticides, and agents that inhibit the growth of and/or kill microorganisms and insects.

The term "anionic formulation" as used herein refers to a formulation comprising one or more anionic compounds (e.g., anionic surfactants).

The keto acid or aromatic carboxylic acid enhances the biocidal efficacy of the quaternary ammonium biocide. These compositions are useful as antimicrobials, fungicides and bactericides and as preservatives in the paper, textile, agricultural and coating industries and in personal care, household, industrial and institutional products. The composition can be used as antisepticThe system is incorporated into a substrate susceptible to microbial growth. For example, the preservative system can be incorporated into or as a personal care product (e.g., shampoo, conditioner, cream, lotion, cosmetic or soap), household product (e.g., fabric softener, laundry detergent and hard surface cleaner), or industrial product (e.g., paint, wood, textile, adhesive, sealant, leather, rope, pulp, plastic, fuel, oil, rubber working fluid, metalworking fluid, starch or mineral pulp (e.g., clay, calcium carbonate or titanium oxide (TiO), for example₃) The slurry of (a)).

Applicants have also found that while quaternary ammonium biocides (e.g., benzethonium chloride) are often inactive in anionic formulations, they are active in such formulations in the presence of keto acids, aromatic carboxylic acids, and salts thereof.

In general, the preservative systems of the present invention function rapidly (e.g., typically reducing the bacterial count by 95, 99, 99.9, or 99.99% within an hour) and maintain their efficacy (e.g., maintaining less than 10cfu/g) over an extended period of time (e.g., at least 28 days).

Quaternary ammonium biocides

According to a preferred embodiment, R⁵is-CH₂CH₂OCH₂CH₂-. More specifically, R⁴Is [2- [2- (4-diisobutylphenoxy) ethoxy]Ethyl radical]. According to another preferred embodiment, R⁴Is benzyl.

Preferred quaternary ammonium biocides include, but are not limited to, benzethonium ([2- [2- (4-diisobutylphenoxy) ethoxy ] ethoxy)]Ethyl radical]Dimethylbenzylammonium) salts (also known as benzethonium salts) such as benzethonium chloride (available from Lonza inc. of Fair land, nj, usa under the designation Hyamine^®1622) And salts of benzalkonium salts, e.g., benzalkonium (available from Lonza inc. of Fair land, new jersey, usa under the designation Barquat^®MB-50 and MB-80). Preferred benzalkonium salts include, but are not limited to, (C)₁₂-C₁₈) Alkyl benzyl dimethyl ammoniumSalt (e.g. chlorinated (C)₁₂-C₁₈) Alkyl benzyl dimethyl ammonium).

According to another preferred embodiment of the invention, the anion X^-Is the anion of a carbonate.

The quaternary ammonium biocide may (but need not) be encapsulated to increase its solubility in the desired solvent or formulation using any method known in the art. For example, the quaternary ammonium biocide may be encapsulated in a cyclodextrin, calixarene (e.g., 4-tert-butylcalix [4] arene), liposome, catezone, or amphoteric betaine polymer.

Polymeric quaternary ammonium biocides

Suitable polymeric quaternary ammonium biocides include, but are not limited to, polymeric quaternary ammonium borates such as those described in U.S. patent nos. 4,970,201 and 5,304,237 (the above patents are incorporated herein by reference) and poly [ oxyethylene (dimethylimino) -ethylene (dimethylimino) (commercially available from Buckman Laboratories, Buckman wscp, montphy, tennessee, usa).

Keto acids

The keto acid may be a cyclic or acyclic keto acid. The term "cyclic ketonic acid" as used herein includes compounds having a ring with a carbonyl-containing group.

Suitable cyclic ketoacids include, but are not limited to, compounds having the formula

And salts thereof, wherein R⁷、R⁸And R⁹Preferably independently of each other is C₁-C₁₀Alkyl radical, C₁-C₁₀Alkenyl radical, C₁-C₁₀Alkenyl, aryl, halogen-substituted aryl or (C)₁-C₁₀Alkyl) aryl. R⁷、R⁸And R⁹Preferably independently of each other is C₁-C₄An alkyl group; or R⁷And R⁸Forming a 5-12 membered ring. Preferred cyclic ketoacids include, but are not limited to, compounds having the formula

And salts thereof. More preferred cyclic ketoacids are dehydroacetic acid and salts thereof (including hydrates thereof), such as sodium dehydroacetate (e.g., sodium dehydroacetate hydrate and sodium dehydroacetate monohydrate).

The cyclic ketonic acid may be, but need not be, encapsulated to increase its solubility in the desired solvent or formulation using any method known in the art. For example, the cyclic keto acid may be encapsulated in a cyclodextrin, calixarene (e.g., 4-tert-butylcalix [4] arene), liposome, catezone, or amphoteric betaine polymer. The cyclic ketonic acid may be encapsulated using any method known in the art.

A preferred combination of cyclic keto acid and quaternary ammonium biocide is dehydroacetic acid or a salt thereof and benzethonium chloride. A more preferred combination is sodium dehydroacetate and benzethonium chloride.

Aromatic carboxylic acids

Suitable aromatic carboxylic acids include, but are not limited to, benzoic acid, derivatives thereof, and salts thereof. According to one embodiment, the aromatic carboxylic acid has the formula

Wherein R is¹⁰And R¹¹Independently is H, -OH or-OC (O) CH₃(ii) a And R is¹²H, Na, K, Ca or Mg. When R is¹²In the case of Ca or Mg, the ratio of aromatic carboxylic acid to Ca or Mg may be 1: 1 or 2: 1。

For example, the aromatic carboxylic acid may be hydroxybenzoic acid, a derivative thereof, or a salt thereof. The preferred hydroxybenzoic acids are salicylic acid and its salts. Suitable salts of salicylic acid include, but are not limited to, sodium salicylate.

Preferred combinations of aromatic carboxylic acids or salts thereof and quaternary ammonium biocides are sodium salicylate and benzethonium chloride.

The composition may comprise a solvent, such as water and a water-miscible solvent, including, but not limited to, alcohols, glycols (e.g., glycerol, diglycerol, butylene glycol, butoxydiglycol, propylene glycol, and dipropylene glycol), esters, ethers, polyethers, and any combination of any of the above. For example, the solvent may comprise water and an alcohol, such as phenoxyethanol and/or benzyl alcohol.

Other additives known to those of ordinary skill in the art may be included in the composition. Suitable additives include, but are not limited to, preservatives, solubilizers, chelating agents (e.g., ethylenediaminetetraacetic acid (EDTA) and salts thereof) and zeolites, surfactants (e.g., cationic, anionic, nonionic, and amphoteric surfactants), antioxidants (e.g., Butylated Hydroxyanisole (BHA) and Butylated Hydroxytoluene (BHT)), amine oxides, tertiary amines, zinc compounds, hydrotropes, fluorides, magnesium salts, calcium salts, carboxylic acids, phosphates, phosphonates, formaldehyde donors, glycereth-7, myristyl myristate, glutaraldehyde, biguanides, natural products (e.g., geraniol, usnic acid, and tea tree oil), and any combination of any of the above.

Suitable preservatives include, but are not limited to, quaternary ammonium chlorides, quaternary ammonium carbonates, benzalkonium, iodine-containing compounds (e.g., 3-iodo-2-propynyl butylcarbamate (IPBC)), hydantoins (e.g., dimethyl hydantoin and halogenated hydantoins), isothiazolinones (isothiazololinones), parabens (e.g., methyl paraben, ethyl paraben and propyl paraben), chloroxylenol, chlorohexidine, phenoxyethanol, benzyl alcohol, phenylethyl alcohol, benzoic acid and salts thereof, chlorobutanol, sorbic acid and salts thereof, triclosan, triclocarban, or any combination of any of the above,

typically, the composition is a water or oil based system, not an emulsion. In oil based systems, it is preferred that the quaternary ammonium biocide is not encapsulated and that the keto acid is not a hydrate. Suitable solvents for oil-based systems are phenoxyethanol and/or benzyl alcohol.

The composition may be a liquid or a solid.

Generally, the weight ratio of (1) the keto acid, aromatic carboxylic acid or salt thereof, or mixture thereof, to (2) the quaternary ammonium biocide, polymeric quaternary ammonium biocide, or mixture thereof is in the range of about 0.00056: 1 to about 1990: 1, preferably between about 0.0056: 1 to about 1400: 1.

To prepare a formulation containing the composition of the present invention, a concentrate is generally first prepared. Table a illustrates the components in a typical concentrate and the ranges in which the components are present based on 100% total weight of the concentrate.

TABLE A

Range	Quaternary ammonium biocides, polymeric quaternary ammonium biocides or mixtures thereof	Keto acid, aromatic carboxylic acid, salt thereof or mixture thereof
Range			In general	About 0.05 to about 90%	About 0.05 to about 99.5%
Preference is given to	About 0.5 to about 40%	About 0.50 to about 70%	In general	About 0.05 to about 90%	About 0.05 to about 99.5%
Preference is given to	About 0.5 to about 40%	About 0.50 to about 70%	More preferably	About 1 to about 20%	About 5 to about 40%

The concentrate is diluted before use, preferably with the same solvent as used in the concentrate. Typically, the use dilution of the composition contains a biocidal, fungicidal or bactericidal effective amount of (1) a quaternary ammonium biocide and/or polymeric quaternary ammonium biocide (i.e., component (a)) and/or (2) a mixture of components (a) and (b) (where component (b) is a keto acid, an aromatic carboxylic acid or salt thereof, or a mixture thereof). Typically, the use dilution will also contain an amount of a keto acid or salt thereof, an aromatic carboxylic acid or salt thereof, or a mixture thereof (i.e., component (b)) effective to enhance (or enhance) the biocidal, fungicidal, or bactericidal effect. Generally, the use dilution contains about 0.0001% by weight or 0.01% to about 2% by weight of the concentrate. According to a preferred embodiment, the use dilution contains about 0.1 to about 1% by weight of the concentrate. Table B illustrates the components in the use dilution and the general ranges in which the components are present based on 100% total weight of the use dilution.

TABLE B

Range	Quaternary ammonium biocides, polymeric quaternary ammonium biocides or mixtures thereof	Keto acid, aromatic carboxylic acid, salt thereof or mixture thereof
Range			In general	About 0.00005 to about 0.45%	About 0.00005 to about 0.5%
Preference is given to	About 0.0005 to about 0.2%	About 0.0005 to about 0.35%	In general	About 0.00005 to about 0.45%	About 0.00005 to about 0.5%
Preference is given to	About 0.0005 to about 0.2%	About 0.0005 to about 0.35%	More preferably	About 0.001 to about 0.1%	About 0.005 to about 0.2%

Yet another preferred embodiment is a preservative formulation comprising dehydroacetic acid, benzethonium chloride, salicylic acid, and optional non-essential ingredients benzoic acid, phenoxyethanol, and benzyl alcohol, which may or may not be present. The formulation in concentrated form may contain, based upon 100% total weight of the preservative formulation, about 5 to about 40% by weight dehydroacetic acid, about 1 to about 20% by weight benzethonium chloride, about 2.5 to about 20% by weight salicylic acid, and, optionally, minor ingredients, about 2.5 to about 20% by weight benzoic acid, about 20 to about 50% by weight phenoxyethanol, and about 5 to about 50% by weight benzyl alcohol. A more preferred embodiment of the preservative formulation contains about 10% by weight dehydroacetic acid, about 5% by weight benzethonium chloride and about 10% by weight salicylic acid and, optionally, other optional ingredients, about 10% by weight benzoic acid, about 35% by weight phenoxyethanol and about 30% by weight benzyl alcohol, based upon 100% total weight of the preservative formulation.

Another embodiment of the invention is a method of inhibiting the growth of microorganisms, bacteria (e.g., staphylococcus aureus (s. aureus, ATCC #6538), pseudomonas aeruginosa (p. aeruginosa, ATCC #9027), and escherichia coli (e.coli, ATCC #8739)) and/or fungi (e.g., candida albicans and Aspergillus niger)) on a substrate by applying an antimicrobially, bactericidally or fungicidally effective amount of a composition of the invention to the substrate. The composition may be applied to the substrate by any method known in the art including, but not limited to, brushing, dipping, soaking, vacuum dipping, and pressure treatment.

The compositions of the present invention may be prepared by mixing a keto acid or salt thereof and/or an aromatic carboxylic acid or salt thereof, a quaternary ammonium biocide, a polymeric quaternary ammonium biocide, a solvent and additives. The mixture may be heated or stirred to accelerate mixing.

Description of the preferred embodiments

The following examples illustrate the invention without limiting it. All parts and percentages are by weight unless otherwise indicated.

Example 1

Each anionic shampoo sample in table 1 below was tested as follows. A standardized mixed bacterial solution was prepared according to the following procedure. 3 agar needle cultures of Staphylococcus aureus (ATCC #6538), Pseudomonas aeruginosa (ATCC #9027) and Escherichia coli (ATCC #8739) were each cultured at about 35 ℃ for about 24 hours. Each needle culture was then washed with 3mL of sterile 0.85% saline solution. The washes of 3 needle-punched cultures were pooled together to form a mixture of organisms. The absorbance of the organism mixture at 530nm was adjusted to about 1.00 by adding a salt solution. The spectrometer was calibrated with a blank sample of saline solution. A measured amount of 5mL of the organism mixture was mixed together to give a standardized mixed bacterial solution. Subsequently, 40g of each shampoo sample was inoculated with 0.2mL of standardized mixed bacterial solution and mixed. 1g of the mixture was added to a sterile 20X 150mm screw-cap tube.

Add 9mL of sterile D/E neutralizer broth to the tube and mix to form 10^-1And (4) diluting the product. Preparation with phosphate buffered Water Up to 10^-6Dilution series dilutions. Serial dilutions were plated on tryptic soy agar and incubated at about 35 ℃ for 2 days. Bacterial counts were taken after 0 and 14 days. The results are shown in table 1.

Anionic protein shampoo compositions comprise 35% by weight sodium lauryl ether sulfate, 25% by weight triethanolamine lauryl sulfate, 3% by weight coconut oil diethanolamide (cocamideDEA), 1% by weight hydrolyzed collagen (available from HormelFoods, austin, mn, usa under the designation Polypro 5000^TM) And 36 wt.% deionized water.

Sodium dehydroacetate monohydrate, sodium salicylate and Hyamine were prepared by mixing appropriate amounts of preservatives with the above anionic protein shampoo compositions^®1622 shampoo sample, and the mixture is heated to about 50 deg.C for about 15 minutes.

TABLE 1

Hair washing agent	Staphylococcus aureus, Pseudomonas aeruginosa, and Escherichia coli (cfu/g)
			Day 0	Day 14
	Anionic protein shampoo compositions without preservative treatment	3.0×10⁶	Day 0	Day 14	3.0×10⁷
0.25% sodium dehydroacetate monohydrate¹And 0.5% Hyamine^®1622^2*		3.0×10⁶	3.0×10⁶	＜10	3.0×10⁷
	0.5% sodium salicylate³And 0.50% Hyamine^®1622^2*	3.0×10⁶	3.0×10⁶	＜10	＜10
0.5% sodium dehydroacetate monohydrate^1*	0.5% sodium salicylate³And 0.50% Hyamine^®1622^2*	3.0×10⁶	3.0×10⁶	4.0×10³	＜10
0.5% sodium dehydroacetate monohydrate^1*	1.0％Hyamine^®1622^2*	3.0×10⁶	3.0×10⁶	4.0×10³	8.5×10⁶
1.0% sodium salicylate^3*	1.0％Hyamine^®1622^2*	3.0×10⁶	3.0×10⁶	5.0×10²	8.5×10⁶

All percentages in table 1 are weight percentages based on 100 wt.% of the total shampoo.

¹Sodium dehydroacetate monohydrate is available from Lonza inc, Fair law, new jersey.

²Hyamine^®1622 Di-isobutoxyethoxyethyldimethylbenzylammonium chloride (benzethonium chloride) is available from Lonza Inc. of Fair Lawn, N.J..

³Sodium salicylate is available from Sigma Chemical co.

^*Concentrations below the indicated preservatives, shampoo containing ≥ 10cfu/g after 14 days.

By the methods described in c.e. kull et al, "mixture of quaternary ammonium compound and long chain fatty acid as antifungal agent", Applied Microbiology, 9: methods for 538-541(1961) calculation of sodium dehydroacetate monohydrate/Hyamine in Table 1^®1622 and sodium salicylate/hydramine^®1622 the synergistic effect of the solution against Staphylococcus aureus, Pseudomonas aeruginosa and Escherichia coli. The value of synergy (synergism value) (Q) in Table 2 was determined_A/Q_a+Q_B/Q_b)。Q_AIs the concentration (in weight percent) of sodium dehydroacetate monohydrate or sodium salicylate that resulted in a 100% retardation of bacterial growth (i.e., resulting in a plate count < 10cfu/g after 14 days). Q_aIs the concentration (in weight percent) of either sodium dehydroacetate monohydrate or sodium salicylate alone required to produce 100% retardation of bacterial growth. Q_BIs Hyamine in a mixture which produced 100% retardation of bacterial growth^®1622 concentration (in weight percent). Q_bIs the Hyamine alone required to produce 100% retardation of bacterial growth^®1622 concentration (in weight percent).

When (Q)_A/Q_a+Q_B/Q_b) When the value of (A) is less than 1, the mixture is synergistically effective. Equal to 1 and greater than 1 (Q)_A/Q_a+Q_B/Q_b) The values of (a) represent the addition and the reaction, respectively.

The results are shown in table 2 below.

TABLE 2

Preservative mixture	Q_A	Q_B	Q_a	Q_b	Q_A/Q_a+Q_B/Q_b
Preservative mixture	Q_A	Q_B	Q_a	Q_b	Q_A/Q_a+Q_B/Q_b	0.25% sodium dehydroacetate monohydrate and 0.50% Hyamine^®1622	0.25％	0.50％	＞0.50％	＞1.00％	＜1
0.5% sodium salicylate and 0.5% hydramine^®1622	0.5％	0.5％	＞1.00％	＞1.00％	＜1		0.25％	0.50％	＞0.50％	＞1.00％	＜1

Example 2

The procedure described in example 1 was repeated with the anionic shampoo in table 3 below. Bacterial counts were taken after 0 and 7 days. Dehydroacetic acid (commercially available from Lonza Inc. of Fair land, nj) and hydramine were prepared by mixing appropriate amounts of preservative and anionic protein shampoo compositions and heating the mixture to about 50 ℃ for about 15 minutes^®1622 shampoo sample. The results are shown in table 3 below.

TABLE 3

Hair washing agent	Staphylococcus aureus, Pseudomonas aeruginosa, and Escherichia coli (cfu/g)
			Day 0	Day 7
	Anionic protein shampoo compositions without preservative treatment	3.0×10⁶	Day 0	Day 7	3.0×10⁷
0.1% dehydroacetic acid and 0.5% Hyamine^®1622		3.0×10⁶	3.0×10⁶	＜10	3.0×10⁷
0.1% dehydroacetic acid and 0.5% Hyamine^®1622	0.2% Dehydroacetic acid	2.5×10⁶	3.0×10⁶	＜10	4.4×10⁴
1.0％Hyamine^®1622	0.2% Dehydroacetic acid	2.5×10⁶	3.0×10⁶	3.0×10⁷	4.4×10⁴

Dehydroacetic acid/Hyamine in Table 3^®1622 the synergistic effect of the mixture against Staphylococcus aureus, Pseudomonas aeruginosa and E.coli was determined by the procedure described in example 1. The results are shown in table 4 below.

TABLE 4

Preservative mixture	Q_A	Q_a	Q_B	Q_b	Q_A/Q_a+Q_B/Q_b
Preservative mixture	Q_A	Q_a	Q_B	Q_b	Q_A/Q_a+Q_B/Q_b	0.1% dehydroacetic acid and 0.5% Hyamine^®1622	0.1％	＞0.2％	0.5％	＞1.0％	＜1

Example 3

The procedure described in example 1 was repeated with the anionic shampoo in table 5 below. Salicylic acid (available from Spectrum Chemical of New Brunswick, N.J.) and Hyamine were prepared by mixing appropriate amounts of preservatives and anionic protein shampoo compositions and heating the mixture to about 50℃ for about 15 minutes^®1622 shampoo sample. The results are shown in table 5 below.

TABLE 5

Hair washing agent	Staphylococcus aureus, Pseudomonas aeruginosa, and Escherichia coli (cfu/g)
			Day 0	Day 14
	Anionic protein shampoo compositions without preservative treatment	3.0×10⁶	Day 0	Day 14	1.0×10⁷
0.1% salicylic acid and 0.5% Hyamine^®1622		3.0×10⁶	3.0×10⁶	＜10	1.0×10⁷
0.1% salicylic acid and 0.5% Hyamine^®1622	1.0％Hyamine^®1622	3.0×10⁶	3.0×10⁶	＜10	8.5×10⁶
0.2% salicylic acid	1.0％Hyamine^®1622	3.0×10⁶	3.1×10⁶	6.5×10⁶	8.5×10⁶

Salicylic acid/Hyamine in Table 5^®1622 the synergistic effect of the solution against Staphylococcus aureus, Pseudomonas aeruginosa and Escherichia coli was determined by the procedure described in example 1. The results are shown in table 6 below.

TABLE 6

Preservative mixture	Q_A	Q_a	Q_B	Q_b	Q_A/Q_a+Q_B/Q_b
Preservative mixture	Q_A	Q_a	Q_B	Q_b	Q_A/Q_a+Q_B/Q_b	0.1% salicylic acid and 0.5% Hyamine^®	0.1％	＞0.2％	0.5％	＞1.0％	＜1

Example 4

Preservative formulations as described in table 7 below were prepared by mixing the ingredients.

TABLE 7

Composition (I)	％(w/w)
Composition (I)	％(w/w)	Dehydroacetic acid	10
Salicylic acid	10	Dehydroacetic acid	10
Salicylic acid	10	Benzoic acid	10
Benzethonium chloride	1	Benzoic acid	10
Benzethonium chloride	1	Phenoxyethanol	37
Benzyl alcohol	32	Phenoxyethanol	37

Example 5

Preservative formulations as described in table 8 below were prepared by mixing the ingredients.

TABLE 8

Composition (I)	％(w/w)
Composition (I)	％(w/w)	Dehydroacetic acid	10
Salicylic acid	10	Dehydroacetic acid	10
Salicylic acid	10	Benzoic acid	10
Benzethonium chloride	5	Benzoic acid	10
Benzethonium chloride	5	Phenoxyethanol	35
Benzyl alcohol	30	Phenoxyethanol	35

Example 6

Each anionic shampoo sample in table 9 below was tested as follows. Standard mixed bacterial solutions were prepared according to the following procedure. 2 agar slant cultures of Candida albicans and 4 agar slant cultures of Aspergillus niger were each cultured at about 25 ℃ for about 48 hours and 7 days, respectively. Each slant culture was washed with 3mL of sterile 0.85% saline solution, collected and immersed in a tissue grinder. A sufficient amount of 0.85% saline solution was added to each slant culture to obtain a visual count of each Candida albicans and Aspergillus niger inoculum under a microscope using a Neubauer hemocytometer. The same volume of standardized inoculum of each of Candida albicans and Aspergillus niger was mixed together to form a standardized mixed fungus solution.

40g of each shampoo sample was inoculated with 0.4mL of standardized mixed fungus solution and mixed. 1g of the mixture was added to a sterile 20X 150mm screw-cap tube.

Add 9mL of sterile D/E neutralizer broth to the tube and mix to form 10^-1And (4) diluting the product. Preparation with phosphate buffered Water Up to 10^-6Dilution series dilutions. Serial dilutions were plated on sabelo glucose agar and incubated at about 25 ℃ for 5 days. Fungal counts were taken after 0 and 14 days. The results are shown in table 9.

Anionic protein shampoo compositions have been described in example 1. Shampoo samples were prepared by mixing appropriate amounts of preservatives and anionic protein shampoo compositions and heating the mixture to about 50 ℃ for about 15 minutes.

TABLE 9

Hair washing agent	Fungus plate count (cfu/g)
	Fungus plate count (cfu/g)		Day 0	Day 14
	Anionic protein shampoo compositions without preservative treatment	1.6×10⁴	Day 0	Day 14	1.5×10⁵
1.0% benzethonium chloride		1.6×10⁴	2.4×10⁵	2.0×10⁴	1.5×10⁵
1.0% benzethonium chloride	0.6% of example 4	2.7×10⁵	2.4×10⁵	2.0×10⁴	1.0×10³
0.6% of example 5	0.6% of example 4	2.7×10⁵	1.1×10⁵	7.0×10¹	1.0×10³

The results in table 9 show that benzethonium chloride is not active in anionic formulations. 1.0% or 10,000ppm benzethonium chloride is not effective in reducing mixed fungi in anionic shampoos. A sample of shampoo containing 0.6% of example 4(60ppm benzethonium chloride) showed a log 2 reduction in fungal plate count. A sample of shampoo containing 0.6% of example 5(300ppm benzethonium chloride) showed a 4 log reduction in fungal plate count. This shows that the preservative mixture of the present invention enhances the fungicidal efficacy of benzethonium chloride in anionic formulations.

Example 7

Each of the skin cream samples in table 10 below was tested according to the procedure described in example 1. The Glyceryl Monostearate (GMS) skin cream described in table 10 was prepared as follows. Polyoxyethylene glycerol monostearate, glyceryl monostearate, cetearyl alcohol, myristyl propionate were mixed in a first vessel and heated to 60 ℃. In a second vessel, glycerol and deionized water were mixed and heated to 60 ℃. The solution in the first container is poured into the second container. The second vessel was maintained at 60 ℃ for 10 minutes. The solution in the second vessel was cooled. The pH of the solution was adjusted to pH 7 with sodium hydroxide to obtain GMS skin cream.

Watch 10

Trade name of ingredient	Chemical name	Amount (% w/w)
Trade name of ingredient	Chemical name	Amount (% w/w)	Aldosperse^®MS-20(Lonza)	Polyoxyethylene (POE) glycerol monostearate	4.00
Aldo^®(Lonza)	Glyceryl monostearate	6.00	Aldosperse^®MS-20(Lonza)	Polyoxyethylene (POE) glycerol monostearate	4.00
Aldo^®(Lonza)	Glyceryl monostearate	6.00	TA 1618(Procter&Gamble)	Cetearyl alcohol	1.50
Lonzest^®143-S(Lonza)	Myristicin propionate	8.00	TA 1618(Procter&Gamble)	Cetearyl alcohol	1.50
Lonzest^®143-S(Lonza)	Myristicin propionate	8.00	Glycon^®G-100(Lonza)	Glycerol	5.00
-	Sterile deionized water	75.50	Glycon^®G-100(Lonza)	Glycerol	5.00
-	Sterile deionized water	75.50	Total of		100.00

A 0.4% sample of example 5 was prepared by mixing the appropriate amount of preservative with GMS cream and heating the mixture to 50 ℃ for 10-15 minutes. The results are shown in table 11 below.

TABLE 11

Skin cream	Staphylococcus aureus, Pseudomonas aeruginosa, and Escherichia coli (cfu/g)
					1 hour	3 hours	24 hours	28 days
	GMS (Gaussian filtered minimum essential oil) cream without preservative treatment	5.3×10⁶	6.3×10⁶	5.0×10⁶	1 hour	3 hours	24 hours	28 days	3.0×10⁶
0.4% of example 5		5.3×10⁶	6.3×10⁶	5.0×10⁶	＜10	＜10	＜10	＜10	3.0×10⁶

Most preservatives have slow efficacy (e.g., requiring 3 or more days to reduce the number of microorganisms), while the preservative systems shown in table 11 work quickly (e.g., typically within 1 hour) and maintain their efficacy over an extended period of time (e.g., within at least 28 days).

All of the above-mentioned patents, applications, articles, publications, and test methods are incorporated herein by reference.

Many modifications of the present invention will come to mind to one skilled in the art to which this invention pertains having the benefit of the teachings presented in the foregoing descriptions. Such obvious variations are intended to be included within the full scope of the appended claims.

Claims

1. Preservative formulation comprising a mixture of the following substances with a synergistic effect:

(a) benzethonium salts; and

(b) at least one of the following:

(i) dehydroacetic acid or a salt thereof; and

(ii) salicylic acid or a salt thereof.

2. A preservative formulation according to claim 1 comprising (i) dehydroacetic acid or a salt thereof and (ii) salicylic acid or a salt thereof.

3. A preservative formulation according to claim 2, further comprising:

(c) benzoic acid or a salt thereof;

(d) phenoxyethanol; and

(e) benzyl alcohol.

4. A preservative formulation according to claim 3, wherein the formulation comprises, based upon 100% total weight of the preservative formulation:

(a)1 to 20 weight percent benzethonium chloride;

(b) (i)5 to 40 weight percent of dehydroacetic acid;

(ii)2.5 to 20 weight percent salicylic acid;

(c)2.5 to 20 weight percent benzoic acid;

(d)20 to 50 weight percent phenoxyethanol; and

(e)5 to 50 wt% of benzyl alcohol.

5. A composition comprising 0.01 to 2 weight percent of the preservative formulation of claim 4.