Patent Application
20200229435
A subject of the present invention is an antibacterial mixture containing 4-(3-ethoxy-4-hydroxyphenyl)butan-2-one and a particular ammonium compound, and also after a cosmetic composition containing such a mixture.
4-(3-Ethoxy-4-hydroxyphenyl)butan-2-one (ketone compound) is a useful substance as a preserving agent for cosmetic compositions, for protecting the compositions against microbial contamination, as described in patent application WO 2011/039445.
However, it is desirable to be able to incorporate said ketone compound in reduced concentration in compositions, especially cosmetic or dermatological compositions, while at the same time maintaining good antimicrobial conservation performance. Combinations of the ketone compound with other preserving agents that have good antimicrobial efficacy are thus sought for this purpose.
The inventors have discovered, unexpectedly, that the combination of 4-(3-ethoxy-4-hydroxyphenyl)butan-2-one with an ammonium compound chosen from a fatty-chain alkyltrimethylammonium salt and an alkyldimethylbenzylammonium salt as defined below, in particular behenyltrimethylammonium chloride or an alkyldimethylbenzylammonium chloride, makes it possible to obtain an antimicrobial mixture with synergistic antimicrobial activity, in particular at least on moulds, especially on Aspergillus niger.
The results of the examples described below show the synergistic antimicrobial activity obtained with the minimum inhibitory concentration (MIC) measurements taken with several mixtures. The antimicrobial activity is considered as being synergistic when the antimicrobial mixture makes it possible to obtain a percentage of strain growth of less than or equal to 25%, or even less than or equal to 20%.
The combination of 4-(3-ethoxy-4-hydroxyphenyl)butan-2-one with a particular fatty-chain alkyltrimethylammonium salt as defined below, in particular behenyltrimethylammonium chloride, makes it possible to obtain an antimicrobial mixture with synergistic antimicrobial activity, in particular on moulds, especially on Aspergillus niger, on yeasts, in particular on Candida albicans, and on gram-negative bacteria, especially on Pseudomonas aeruginosa.
The combination of 4-(3-ethoxy-4-hydroxyphenyl)butan-2-one with an alkyldimethylammonium salt as defined below, in particular an alkyldimethylbenzylammonium chloride, makes it possible to obtain an antimicrobial mixture with synergistic antimicrobial activity, in particular on moulds, especially on Aspergillus niger.
More precisely, a subject of the invention is an antimicrobial mixture comprising, or constituted by (or consisting of), 4-(3-ethoxy-4-hydroxyphenyl)butan-2-one and an ammonium compound chosen from:
i) an alkyltrimethylammonium salt of formula R—N+(CH3)3 X− (I) in which R denotes an alkyl group containing from 20 to 24 carbon atoms, X− denotes a halide ion, in particular chloride or bromide, or a methosulfate ion;
ii) an alkyldimethylbenzylammonium salt of formula (II):
C6H5—CH2—N+(CH3)2R X− (II)
in which R denotes an alkyl radical containing from 8 to 18 carbon atoms,
X− denotes a halide anion such as chloride or bromide.
A subject of the invention is also a composition, especially a cosmetic composition, comprising, in a physiologically acceptable medium, said mixture described previously.
A further subject of the invention is a process for the non-therapeutic cosmetic treatment of keratin materials, comprising the application to the keratin materials of a composition as described previously. The process may be a cosmetic process for caring for or making up or cleansing keratin materials.
A subject of the invention is also a process for conserving a composition comprising a physiologically acceptable medium, in particular a cosmetic or dermatological composition, characterized in that it consists in incorporating into said composition an antimicrobial mixture as described previously.
A subject of the invention is also the use of the antimicrobial mixture described previously for conserving a composition comprising a physiologically acceptable medium.
4-(3-Ethoxy-4-hydroxyphenyl)butan-2-one is a compound of formula:
According to a first embodiment, a subject of the invention is an antimicrobial mixture comprising, or constituted by (or consisting of), 4-(3-ethoxy-4-hydroxyphenyl)butan-2-one and an alkyltrimethylammonium salt of formula R—N+(CH3)3 X− (I) in which R denotes an alkyl group containing from 20 to 24 carbon atoms, X− denotes a halide ion, in particular chloride or bromide, or a methosulfate ion.
For the alkyltrimethylammonium salt of formula (I) described previously, R is preferably a behenyl group.
Preferably, X− is a chloride anion.
Advantageously, the alkyltrimethylammonium salt (I) is behenyltrimethylammonium chloride (INCl name: behentrimonium chloride).
Behenyltrimethylammonium chloride may be used as a mixture at 79% by weight with 18% of isopropyl alcohol and 3% of water sold under the name Genamin KDMF by the company Clariant.
Advantageously, 4-(3-ethoxy-4-hydroxyphenyl)butan-2-one and the trimethylammonium salt (I) are present in said mixture in a content such that the 4-(3-ethoxy-4-hydroxyphenyl)butan-2-one/salt (I) (preferably behenyltrimethylammonium chloride) weight ratio ranges from 0.08 to 80, preferably from 0.45 to 70 and preferentially from 1.5 to 50.
The antimicrobial mixture according to the invention has synergistic antimicrobial activity, in particular on moulds, especially on Aspergillus niger, on yeasts, in particular on Candida albicans, and on gram-negative bacteria, in particular on Pseudomonas aeruginosa.
Preferentially, the antimicrobial mixture according to the invention contains behenyltrimethylammonium chloride.
The antimicrobial mixture may have a 4-(3-ethoxy-4-hydroxyphenyl)butan-2-one/salt (I) (preferably behenyltrimethylammonium chloride) weight ratio ranging from 10 to 60, preferably ranging from 10 to 55 and preferentially ranging from 15 to 40, and better still ranging from 20 to 30. Such a mixture has good antimicrobial activity on yeasts, especially on Candida albicans.
The antimicrobial mixture may have a 4-(3-ethoxy-4-hydroxyphenyl)butan-2-one/salt (I) (preferably behenyltrimethylammonium chloride) weight ratio ranging from 0.08 to 5, preferably ranging from 0.45 to 4.5, preferentially ranging from 0.45 to 3, better still from 0.4 to 2.5, and preferentially ranging from 1.5 to 3. Such a mixture has good antimicrobial activity on moulds, especially on Aspergillus niger.
The antimicrobial mixture may have a 4-(3-ethoxy-4-hydroxyphenyl)butan-2-one/salt (I) (preferably behenyltrimethylammonium chloride) weight ratio ranging from 3 to 80, preferably ranging from 3 to 70, preferentially ranging from 3 to 50 and better still ranging from 3 to 45. Such a mixture has good antimicrobial activity on gram-negative bacteria, especially on Pseudomonas aeruginosa.
According to a second embodiment, a subject of the invention is an antimicrobial mixture comprising, or constituted by (or consisting of), 4-(3-ethoxy-4-hydroxyphenyl)butan-2-one and an alkyldimethylbenzylammonium salt of formula (II):
C6H5—CH2—N+(CH3)2R X− (II)
in which R denotes an alkyl radical containing from 8 to 18 carbon atoms,
X− denotes a halide anion such as chloride or bromide.
For the alkyldimethylbenzylammonium salt of formula (II) described previously, R is preferably an alkyl group comprising from 10 to 16 carbon atoms and preferentially from 12 to 14 carbon atoms.
Preferably, X− is a chloride anion.
Use is preferably made of an alkyldimethylbenzylammonium chloride (INCl name: benzalkonium chloride).
Advantageously, the alkyldimethylbenzylammonium salt is a mixture of lauryldimethylbenzylammonium chloride (compound IIa; R=C12 alkyl) and of myristyldimethylbenzylammonium chloride (compound IIb; R=C14 alkyl).
Use is preferably made of a mixture chosen from:
The percentages indicated are molar percentages relative to the total number of moles of said mixture.
Advantageously, 4-(3-ethoxy-4-hydroxyphenyl)butan-2-one and the alkyldimethylbenzylammonium salt (II) are present in said mixture in contents such that the 4-(3-ethoxy-4-hydroxyphenyl)butan-2-one/salt (II) (preferably an alkyldimethylbenzylammonium chloride) weight ratio ranges from 5 to 120, preferably from 5 to 100, preferentially from 5 to 85, more preferentially from 30 to 85 and in particular from 35 to 85.
The antimicrobial mixture according to the invention has synergistic antimicrobial activity, in particular on moulds, especially on Aspergillus niger.
Preferentially, the antimicrobial mixture according to the invention contains an alkyldimethylbenzylammonium chloride.
A subject of the invention is also a composition comprising, in a physiologically acceptable medium, the antimicrobial mixture described previously.
The term “physiologically acceptable medium” means a medium that is compatible with human keratin materials such as the skin, the scalp, the hair and the nails. Said medium may comprise one or more additional ingredients other than the ketone compound and the ammonium compound described previously.
The compound 4-(3-ethoxy-4-hydroxyphenyl)butan-2-one may be present in the composition according to the invention at an amount ranging from 0.01% to 5% by weight relative to the total weight of the composition, preferably ranging from 0.01% to 3% by weight, preferentially ranging from 0.01% to 2.5% by weight and more preferentially ranging from 0.01% to 2% by weight.
The composition may comprise at least one additional ingredient chosen from water, oils, polyols containing from 2 to 10 carbon atoms, gelling agents, surfactants, film-forming polymers, dyestuffs, fragrances, fillers, UV-screening agents, plant extracts, cosmetic and dermatological active agents, and salts.
The composition according to the invention may comprise an aqueous phase.
The composition may comprise water, which may be present at a content ranging from 5% to 90% by weight relative to the total weight of the composition, and preferably ranging from 35% to 75% by weight.
The composition may also comprise a polyol that is water-miscible at room temperature (25° C.), especially chosen from polyols especially containing from 2 to 10 carbon atoms, preferably containing from 2 to 6 carbon atoms, such as glycerol, propylene glycol, 1,3-propanediol, butylene glycol, pentylene glycol, hexylene glycol, dipropylene glycol, diethylene glycol or diglycerol. Advantageously, the composition according to the invention comprises 1,3-propanediol, especially in a content ranging from 0.1% to 20% by weight, preferably ranging from 0.1% to 10% by weight and preferentially ranging from 0.5% to 5% by weight, relative to the total weight of the composition.
The compositions according to the invention may be in the form of oil-in-water (O/W) emulsions, water-in-oil (W/O) emulsions or multiple emulsions (triple: W/O/W or O/W/O), oily solutions, oily gels, aqueous solutions, aqueous gels, solid compositions. These compositions are prepared according to the usual methods.
The compositions according to the invention may be more or less fluid and may have the appearance of a white or coloured cream, an ointment, a milk, a lotion, a serum, a paste or a foam. They may be optionally applied to the skin in aerosol form. They may also be in solid form, for example in the form of a stick or a compact powder.
The composition according to the invention may especially be in the form of:
A subject of the invention is also a process for preparing a composition, especially a cosmetic or dermatological composition, comprising a step of mixing 4-(3-ethoxy-4-hydroxyphenyl)butan-2-one, the ammonium compound described previously, and one or more additional ingredients, especially cosmetic or dermatological ingredients, such as those described previously.
The invention is illustrated in greater detail in the example that follows. The amounts of the ingredients are expressed as weight percentages.
The demonstration of a synergistic antimicrobial activity effect with a mixture of 4-(3-ethoxy4-hydroxyphenyl)butan-2-one (referred to as substance A) and of ammonium compound (referred to as substance B) is performed by calculating the synergy index (or FIC index).
FIC Index=(MICa with B/MICa)+(MICb with A/MICb)
with:
This formula was described for the first time in the article by F. C. Kull, P. C. Eisman, H. D. Sylwestrowka, and R. L. Mayer, Applied Microbiology 9:538-541, 1961.
For each compound tested alone, the MIC is considered as the first concentration which makes it possible to obtain a microbial growth percentage of less than or equal to 25%.
As regards the combinations tested, MICa with b and MICb with a are the respective concentrations of A and of B in the combinations which make it possible to obtain a microbial growth percentage of less than or equal to 25%.
When the FIC index value is less than or equal to 1, it is considered that the combination of test compounds has a synergistic effect.
The results obtained are summarized in the following tables.
The combination of compounds A and B was tested on the following strains or a part of these strains: Aspergillus niger, Candida albicans, Pseudomonas aeruginosa.
The microbial strain Aspergillus niger ATCC 6275, and a double-concentration Sabouraud broth liquid culture medium supplemented with polyoxyethylenated (20 OE) sorbitan monopalmitate (Tween 40 from Croda) and Phytagel© BioReagent were used.
The microbial strain Candida albicans ATCC 10231 and a double-concentration Sabouraud broth liquid culture medium were used.
The microbial strain Pseudomonas aeruginosa ATCC 9027 and a double-concentration nutritive broth liquid culture medium were used.
A 96-well microplate and an incubation time of 32.5° C. are used.
The incubation time of the microplate is:
For each compound:
A=4-(3-ethoxy-4-hydroxyphenyl)-2-butanone compound
B=behenyltrimethylammonium chloride (as a mixture at 79% by weight with 18% of isopropyl alcohol and 3% of water sold under the name Genamin KDMF by the company Clariant*)
A 10% (weight/volume) stock solution was prepared by mixing 1 g of compound in 9 ml of aqueous 1% agar solution. Successive dilutions were made with the 1% agar solution.
50 μL of each of the daughter solutions obtained containing compound A or B are added to the microplate wells. 100 μL of Sabouraud liquid nutrient broth seeded with the strain Aspergillus niger and 50 μL of aqueous 1% agar solution are also added thereto.
50 μL of each of the daughter solutions obtained containing compound A and 50 μL of each of the daughter solutions obtained containing compound B are added to the microplate wells. 100 μL of Sabouraud liquid nutrient broth seeded at double concentration with the strain Aspergillus niger are also added thereto.
A positive microbial growth control was also prepared. The positive microbial growth control corresponds to a mixture of 100 μL of aqueous 1% agar solution with 100 μL of Sabouraud liquid nutrient broth seeded at double concentration with the strain Aspergillus niger in the absence of compounds A and B.
An absorbance control was performed in parallel on compounds A and B alone. This control corresponds to 100 μL of double concentration sterile Sabouraud liquid nutrient broth+100 μL of double concentration compound A or B.
In the three cases (absorbance control, growth control and test), the final volume present in each of the microplate wells is 200 μL.
In the two cases (test and control), the inoculum represents the concentration of the strain Aspergillus niger present in the final volume of the wells (200 μL) and is between 2 and 6×105 cfu/ml of Aspergillus niger.
The minimum inhibitory concentration (MIC) of each compound A and B alone and in combination was determined in a known manner by means of optical density measurements at a wavelength of 620 nm.
The test as described above (tests, absorbance control and growth control) was performed again to test the combination A+B on the strains Candida albicans and Pseudomonas aeruginosa.
The following results were obtained with
B1=behenyltrimethylammonium chloride (as a mixture at 79% by weight with 18% of isopropyl alcohol and 3% of water sold under the name Genamin KDMF by the company Clariant*)
The results obtained show synergistic inhibitory activity for the mixtures:
i) 0.025% of A and 0.002% of B1, i.e. ratio A/B1=12.5
ii) 0.05% of A and 0.002% of B1, i.e. ratio A/B1=25
iii) 0.1% of A and 0.002% of B1, i.e. ratio A/B1=50
Aspergillus niger
The results obtained show synergistic inhibitory activity for the mixtures:
i) 0.05% of A and 0.4% of B1, i.e. ratio A/B1=0.125
ii) 0.1% of A and 0.4% of B1, i.e. ratio A/B1=0.25
iii) 0.1% of A and 0.2% of B1, i.e. ratio A/B1=0.5
iv) 0.1% of A and 0.1% of B1, i.e. ratio A/B1=1
v) 0.1% of A and 0.049% of B1, i.e. ratio A/B1=2
vi) 0.2% of A and 0.4% of B1, i.e. ratio A/B1=0.5
vii) 0.2% of A and 0.2% of B1, i.e. ratio A/B1=1
viii) 0.2% of A and 0.1% of B1, i.e. ratio A/B1=2
ix) 0.2% of A and 0.049% of B1, i.e. ratio A/B1=4
Pseudomonas aeruginosa
The results obtained show synergistic inhibitory activity for the mixtures:
i) 0.0625% of A and 0.0158% of B1, i.e. ratio A/B1=3.95
ii) 0.125% of A and 0.0158% of B1, i.e. ratio A/B1=7.91
iii) 0.25% of A and 0.0158% of B1, i.e. ratio A/B1=15.82
iv) 0.5% of A and 0.0158% of B1, i.e. ratio A/B1=31.64
v) 0.5% of A and 0.0079% of B1, i.e. ratio A/B1=63.29
The demonstration of a synergistic antimicrobial activity effect with a mixture of 4-(3-ethoxy-4-hydroxyphenyl)butan-2-one (referred to as substance A) and of (C12-C14)alkyldimethylbenzylammonium chloride (referred to as substance B2) is performed according to the protocol described in Example 1, using the strain Aspergillus niger.
B2=(C12-C14)alkyldimethylbenzylammonium chloride=mixture of 70 mol % of benzyldimethyldodecylammonium chloride and 30 mol % of benzyldimethyltetradecylammonium chloride (sold under the name Benzalkonium chloride product No. 12060 by the company Sigma-Aldrich)
The following results were obtained:
Aspergillus niger
The results obtained show synergistic inhibitory activity for the mixtures:
i) 0.05% of A and 0.005% of B2, i.e. ratio A/B2=10
ii) 0.1% of A and 0.005% of B2, i.e. ratio A/B2=20
iii) 0.1% of A and 0.0025% of B2, i.e. ratio A/B2=40
iv) 0.2% of A and 0.005% of B2, i.e. ratio A/B2=40
v) 0.2% of A and 0.0025% of B2, i.e. ratio A/B2=80
| Number | Date | Country | Kind |
|---|---|---|---|
| 1757744 | Aug 2017 | FR | national |
| 1757746 | Aug 2017 | FR | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2018/067300 | 6/27/2018 | WO | 00 |
