Topical skin care compositions with c16:1 fatty acid

Abstract

The invention provides a topical skin care composition comprising: (i) one or more C16:1 fatty acids including sapienic acid, and (ii) 12-hydroxystearic acid; in which the weight ratio of (i):(ii) ranges from 10:1 to 1:10, in which the total amount of C16:1 fatty acid ranges from 0.01 to 5% (by weight based on the total weight of the composition), and in which the amount of sapienic acid ranges from 0.01 to 5% (by weight based on the total weight of the composition), and in which the amount of 12-hydroxystearic acid ranges from 0.01 to 5% (by weight based on the total weight of the composition). The composition of the invention has enhanced efficacy against S. aureus and can be used for the maintenance or restoration of a healthy skin microbiome. The compositions can be used in the treatment of atopic dermatitis.

Description

[0001] TOPICAL SKIN CARE COMPOSITIONS WITH C16:1 FATTY ACID

[0002] Field of the Invention

[0003] The present invention relates to topical skin care compositions with C16:1 fatty acid and their use for the maintenance or restoration of a healthy skin microbiome.

[0004] Background of the Invention

[0005] The skin is the body’s largest and most exposed organ system. Recent estimates of the epithelial surface area, accounting for hair follicles and sweat glands, suggest an expanse as large as 30m2. This vast region is densely populated with microorganisms that interact and compete to colonize and survive. These microorganisms, their combined genetic material, and the environment in which they live collectively form the human skin microbiome.

[0006] Within the Staphylococcus genus, the most common skin commensals are members of the coagulase-negative Staphylococci (CoNS). The skin of healthy individuals is colonized by a mixture of these CoNS, present at different ratios depending on whether the site is dry, moist, or sebaceous. The most frequently isolated and best characterized CoNS from human skin is Staphylococcus epidermidis.

[0007] CoNS play a pivotal role in the orchestration of cutaneous homeostasis and immune competence. Studies show that CoNS can drive epidermal barrier development, educate, or tune the cutaneous immune response, and produce a variety of antimicrobial molecules to promote barrier function and integrity.

[0008] Dysregulation of these systems can disrupt the structure of the microbial community, a condition known as “dysbiosis”. Dysbiosis refers to the lack of balance among microbial communities and is correlated with skin pathologies such as atopic dermatitis (AD). Dysbiosis is also correlated with non-pathological conditions such as sensitive, dry, and rough skin.

[0009] Microbial dysbiosis in AD is characterized by a reduced microbial diversity, specifically manifested as a decrease in the genera Cutibacterium, Streptococcus, Acinetobacter, Corynebacterium and Prevotella, and a marked increase of Staphylococcus, especially of S. aureus. The reduced microbial diversity is particularly evident during severe flares of the disease, with the reported composition of Staphylococcus usually reduced to a single S. aureus strain.

[0010] The main intervention strategies used for the treatment of S. aureus involve topical antimicrobials and / or systemic antibiotics. Although such treatments are usually effective, they may also deplete or eliminate beneficial commensals such as Staphylococcus epidermidis and other CoNS. Hence, more targeted approaches are needed that aim to restore a healthy skin microbiome and promote the recovery of commensals.

[0011] Recent studies indicate that C16 monounsaturated fatty acids (hexadecenoic acid, C16:1) such as 6-c / s-C16:1 (sapienic acid) possess a selective antibacterial activity against S. aureus. Sapienic acid, which is present in human sebum, is considered to control the skin microbiota as a natural antimicrobial agent. Indeed, the level of sapienic acid is lower in atopic dermatitis patients than in healthy individuals and is inversely correlated to the abundance of S. aureus.

[0012] The present inventors have found that enhanced efficacy against S. aureus can be obtained when C16:1 fatty acids such as sapienic acid are combined with certain actives.

[0013] Summary of the Invention

[0014] The invention provides a topical skin care composition comprising:

[0015] (i) from 0.01 to 10 wt.% (by weight based on the total weight of the composition) of one or more C16:1 fatty acids, and

[0016] (ii) from 0.01 to 10 wt.% (by weight based on the total weight of the composition) of 12-hydroxystearic acid;

[0017] in which the weight ratio of (i):(ii) ranges from 10:1 to 1:10.

[0018] The invention also provides a cosmetic, non-therapeutic method for balancing the relative abundance of Staphylococcus strains within the skin microbiome, the method comprising the step of topically applying the composition as described above to the skin.

[0019] The invention also provides the cosmetic, non-therapeutic use of the composition as described above for balancing the relative abundance of Staphylococcus strains within the skin microbiome. The invention also provides the composition as described above for use in the treatment of skin pathologies associated with S. aureus overgrowth, such as atopic dermatitis (AD).

[0020] Detailed Description of the Invention

[0021] The term "topical application" means to apply the skin care composition onto the surface of the skin.

[0022] The term “C16:1 fatty acid” as used herein refers to a fatty acid with a hydrocarbyl chain having 16 carbon atoms and one carbon-carbon double bond.

[0023] In the composition of the invention, the C16:1 fatty acid may be used in the free acid form or in the form of a derivative such as a salt or ester. Examples of salts or esters include ammonium, sodium, potassium, magnesium, or calcium salts, lower (C1-4) alkyl esters (e.g. methyl or ethyl esters), and mono-, di- or triglycerides. Preferably the C16:1 fatty acid is used in the free acid form.

[0024] The C16:1 fatty acid may suitably correspond to general formula (I):

[0025] CH3(CH2)mCH=CH(CH2)nCOOH (I)

[0026] in which m is an integer ranging from 1 to 11, n is an integer ranging from 1 to 1 and m+n = 12. Preferably m ranges from 4 to 9. Preferably the double bond is of the Z-configuration,

[0027] Specific examples of preferred C16:1 fatty acids of general formula (I) for use in compositions of the invention include (Z)-hexadec-6-enoic acid (also termed 16:1n-10 or sapienic acid), (Z)-hexadec-7-enoic acid (also termed 16:1n-9 or hypogeic acid) and (Z)-hexadec-9-enoic acid (also termed 16:1n-7 or palmitoleic acid). Sources of these materials include marine oils, microbial ferments, and botanical oils such as macadamia (Macadamia integrifolia) nut oil, sea buckthorn (Hippophae rhamnoides) pulp oil and Thunbergia alata seed oil.

[0028] Sapienic acid and hypogeic acid are particularly preferred for use in compositions of the invention, in view of their higher selectivity towards S. aureus than palmitoleic acid. Sapienic acid and hypogeic acid each have an antimicrobial activity against S. aureus which is over 100-fold higher than that for S. epidermidis. Sapienic acid is most preferred since this has the highest antimicrobial activity whilst also demonstrating selectivity against S. aureus. Mixtures of any of the above-described materials may also be used.

[0029] The composition of the invention will typically contain from about 0.01 to about 5%, such as about 0.1 to 2% (by weight based on the total weight of the composition) of C16:1 fatty acid.

[0030] The composition of the invention will preferably contain from about 0.01 to about 5%, such as about 0.1 to 2% (by weight based on the total weight of the composition) of total C16:1 fatty acid and from about 0.01 to about 5%, such as about 0.1 to 2% (by weight based on the total weight of the composition) of sapienic acid, hypogeic acid and palmitoleic acid or a mixture thereof.

[0031] The composition of the invention will more preferably contain from about 0.01 to about 5%, such as about 0.1 to 2% (by weight based on the total weight of the composition) of total C16:1 fatty acid, and from about 0.01 to about 5%, such as about 0.1 to 2% (by weight based on the total weight of the composition) of sapienic acid.

[0032] 12-hydroxystearic acid conforms generally to the following structural formula (II):

[0033]

[0034] The composition of the invention will typically contain from about 0.01 to about 5% and preferably contains from about 0.1 to 2% of 12-hydroxystearic acid.

[0035] In the composition of the invention, the weight ratio of total C16:1 fatty acid to 12-hydroxystearic acid typically ranges from about 5:1 to about 1:5, preferably from about 3:1 to about 1:3 and most preferably about 1.5:1 to about 1:1.5.

[0036] In preferred compositions of the invention, the weight ratio of total C16:1 fatty acid to 12-hydroxystearic acid ranges from about 5:1 to about 1:5, preferably from about 3:1 to about 1:3 and most preferably about 1.5:1 to about 1:1.5 and the weight ratio of sapienic acid to 12- hydroxystearic acid ranges from about 5:1 to about 1:5, preferably from about 3:1 to about 1:3 and most preferably about 1.5:1 to about 1:1.5.

[0037] Product Forms

[0038] Topical skin care compositions of the invention are preferably cosmetic compositions. As used herein, “cosmetic compositions” denotes compositions which are used to regulate and / or improve cosmetic qualities of the skin (as opposed to curing, treating, or preventing a disease or disorder). Such cosmetic qualities are subject to regulation and / or improvement both in healthy subjects as well as those which present diseases or disorders of the skin (such as psoriasis, lichen planus, folliculitis, or atopic dermatitis).

[0039] Examples of regulating and / or improving cosmetic qualities of the skin include reducing skin malodour, providing a smoother, more even skin texture; improving the hydration status or moisturization of the skin; improving skin barrier properties; reducing skin sensitivity and reducing the appearance of redness or skin blotches.

[0040] Compositions of the invention can be formulated in a variety of forms for topical application and will generally include a cosmetically acceptable vehicle. The term “cosmetically acceptable” means that the vehicle is suitable for topical application to the skin, has good aesthetic properties, is compatible with the other ingredients, and will not cause any safety or toxicity concerns.

[0041] The vehicle may comprise an aqueous phase, an oil phase, an alcohol, a silicone phase, or a mixture thereof, and may be in the form of an emulsion. Emulsions can have a range of consistencies including thin lotions (which may also be suitable for spray or aerosol delivery), creamy lotions, light creams, and heavy creams.

[0042] Exemplary emulsions include water-in-oil emulsions, oil-in-water emulsions, silicone-in-water emulsions, water-in-silicone emulsions, polyol-in-silicone emulsions, silicone-in-polyol emulsions, polyol-in-oil emulsions, oil-in-polyol emulsions, wax-in-water emulsions, and water-oil-water triple emulsions. Preferred emulsions include oil-in-water emulsions and water-in-oil emulsions. Topical skin care compositions of the invention which are in the form of an emulsion typically have an oil phase containing at one or more cosmetically acceptable fatty materials which may be liquid or solid at room temperature (25°C).

[0043] Suitable cosmetically acceptable fatty materials include naturally derived oils (such as sunflower oil, borage oil, soybean oil, castor oil, olive oil and almond oil); esters of monoalcohols or of glycols with monocarboxylic or polycarboxylic acids, at least one of the alcohols and / or acids comprising at least one hydrocarbon-based chain containing at least 6 carbon atoms (such as octyl palmitate, isopropyl myristate, isopropyl palmitate, isopropyl isostearate, hexyl laurate, isohexyl laurate, isohexyl palmitate, decyl oleate, isodecyl oleate, hexadecyl stearate, decyl stearate, dihexyldecyl adipate, lauryl lactate, myristyl lactate, cetyl lactate, oleyl stearate, oleyl oleate, oleyl myristate, lauryl acetate, cetyl propionate, isononyl isononanoate, propylene glycol dicaprate, diisopropyl adipate, dibutyl adipate, and oleyl adipate); ethers (such as dicapryl ether); fatty alcohols (such as cetyl alcohol, stearyl alcohol and behenyl alcohol); isoparaffins (such as isooctane, isododecane and isohexadecane); silicone oils (such as dimethicones, cyclic silicones, and polysiloxanes); and hydrocarbon oils (such as mineral oil, petrolatum and polyisobutene); saturated fatty acids containing from 8 to 30 carbon atoms, (such as stearic acid, lauric acid and palmitic acid); vegetable fats (such as cocoa butter, coconut oil, palm oil and shea butter) ; natural or synthetic waxes (such as lanolin wax, beeswax, carnauba wax, candelilla wax, paraffin wax, lignite wax, microcrystalline waxes, ceresin, ozokerite, and polyethylene waxes), hydrogenated oils which are solid at 25° C (such as hydrogenated castor oil, hydrogenated jojoba oil, hydrogenated palm oil, hydrogenated tallow and hydrogenated coconut oil) and fatty esters that are solid at 25°C (such as C20-40 alkyl stearate).

[0044] Mixtures of any of the above-described materials may also be used.

[0045] Topical skin care compositions of the invention which are in the form of an emulsion typically have an aqueous phase, with the amount of water in such an emulsion suitably ranging from about 5 to about 95%, preferably from about 35 to about 80% (by weight based on the total weight of the composition). The aqueous phase may also include one or more organic liquids that are miscible with water at room temperature (25°C). Exemplary water-miscible organic liquids include monohydric and polyhydric alcohols and derivatives thereof such as C2-C6 alkanols (such as ethanol and isopropanol); C2-C10 glycols and polyols (such as glycerol, propylene glycol, butylene glycol, pentylene glycol, hexylene glycol, caprylyl glycol, dipropylene glycol, and diethylene glycol); C3-C16 glycol ethers (such as mono-, di-, or tripropylene glycol (C1-C4) alkyl ethers and mono-, di-, or triethylene glycol (C1-C4) alkyl ethers) and polyethylene glycol having 2 to 12 oxyethylene units.

[0046] Topical skin care compositions of the invention which are in the form of an emulsion generally include emulsifiers and solubilizers, to enable two or more immiscible components to be combined homogeneously and to help stabilize the composition. The amount of emulsifier and solubilizer in such an emulsion suitably ranges from about 0.1 to about 30%, preferably from about 1 to about 8% (by weight based on the total weight of the composition). Emulsifiers that may be used to form O / W or W / O emulsions include sorbitan oleate, sorbitan sesquioleate, sorbitan isostearate, sorbitan trioleate, PEG-20 sorbitan isostearate, polyglyceryl-3-diisostearate, polyglycerol esters of oleic / isostearic acid, polyglyceryl-6 hexaricinolate, polyglyceryl-4-oleate, polyglyceryl-4 oleate / PEG-8 propylene glycol cocoate, polyglyceryl-2 dipolyhydroxystearate, PEG-30 dipolyhydroxystearate, oleamide DEA, TEA myristate, TEA stearate, magnesium stearate, sodium stearate, potassium laurate, potassium ricinoleate, sodium cocoate, sodium tallowate, potassium castorate, sodium oleate, cetyl phosphate, diethanolamine cetyl phosphate, potassium cetyl phosphate, sodium glyceryl oleate phosphate, dimethicone copolyol, cetyl dimethicone copolyol, octyldimethicone ethoxyglucoside copolyol, dimethicone copolyol crosspolymer and laurylmethicone copolyol.

[0047] Mixtures of any of the above-described materials may also be used.

[0048] Topical skin care compositions of the invention may also take the form of a skin cleanser incorporating one or more cleansing surfactants which, when combined with water and mechanically agitated, generate a foam or lather. The amount of cleansing surfactant suitably ranges from about 5 to about 40%, preferably from about 10 to about 35% (by weight based on the total weight of the composition). Exemplary cleansing surfactants include anionic surfactants such as ammonium lauroyl sarcosinate, sodium trideceth sulfate, sodium lauroyl sarcosinate, sodium myristoyl sarcosinate, ammonium laureth sulfate, sodium laureth sulfate, ammonium lauryl sulfate, sodium lauryl sulfate, ammonium cocoyl isethionate, sodium cocoyl isethionate, sodium lauroyl isethionate, sodium cocoyl glycinate, sodium lauroyl glycinate, sodium methyl cocoyl taurate, sodium methyl lauroyl taurate, sodium methyl oleoyl taurate, sodium cetyl sulfate, sodium lauroyl lactylate and triethanolamine lauroyl lactylate and mixtures thereof; nonionic surfactants such as lauramine oxide, cocoamine oxide, decyl polyglucose, lauryl polyglucose, sucrose cocoate and sucrose laurate and mixtures thereof; and amphoteric surfactants such as disodium lauroamphodiacetate, sodium lauroamphoacetate, cetyl dimethyl betaine, cocoamidopropyl betaine and cocoamidopropyl hydroxy sultaine and mixtures thereof. Mixtures of any of the above-described materials may also be used.

[0049] Topical skin care compositions of the invention may also be formulated in a single-phase carrier such as water and / or one or more water miscible organic liquids (such as the monohydric and polyhydric alcohols and derivatives thereof described above).

[0050] Topical skin care compositions of the invention may also be formulated in solid forms such as gels or sticks.

[0051] Combinations of any of the above-described product forms may also be used.

[0052] Skin Care Actives

[0053] Topical skin care compositions of the invention may include additional skin care actives (for improving the physical and / or aesthetic characteristics of the skin). Examples of additional skin care actives which are suitable for use in the invention include vitamins, minerals and / or antioxidants, emollients, humectants, skin anti-hyperpigmentation agents, sunscreens, antiirritants, exfoliating agents, and mixtures thereof.

[0054] Vitamins, minerals and / or antioxidants suitable for use in compositions of the invention include natural botanical antioxidants derived from plant materials such as fruits, vegetables, herbs and spices (such as goji berry, white tea, rosemary, green tea, grape seed and lemongrass extracts); vitamin A and its precursors or derivatives (such as beta-carotene, retinyl palmitate); vitamin B3 and its precursors or derivatives (such as niacinamide); vitamin B5 and its precursors or derivatives (such as panthenol and its precursors or derivatives); vitamin C and its precursors or derivatives (such as tetrahexyldecyl ascorbate, ascorbyl palmitate); vitamin E and its precursors or derivatives (such as d-alpha-tocopherol, tocopheryl acetate); vitamin K and its precursors or derivatives; selenium and its derivatives (such as L-selenomethionine); and alpha lipoic acid.

[0055] Emollients suitable for use in compositions of the invention act to increase and maintain moisture in the skin by providing a protective coating to impede epidermal water loss. Examples of emollients include C10-20 fatty alcohols and acids (such as cetyl, myristyl, palmitic and stearyl alcohols and acids); and C10-40 hydrocarbons (such as mineral oil, petroleum jelly, squalene and isoparaffins).

[0056] Humectants suitable for use in compositions of the invention act to increase and maintain moisture in the skin by attracting water to the stratum corneum of the epidermis. Examples of humectants include amino acids, chondroitin sulfate, glycerin, diglycerin, triglycerin, polyglycerin, polypropylene glycol, polyethylene glycol, ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, hexylene glycol, 1,3-butylene glycol, 1,4-butylene glycol, ethylene glycol monoalkyl ether, diethylene glycol monoalkyl ether, erythritol, fructose, glucose, maltose, sucrose, lactose, xylose, inositol, lactitol, xylitol, sorbitol, mannitol, maltitol, panthenol, pentaerythritol, 1,2,6-hexanetriol, honey, hyaluronic acid, hydrogenated honey, hydrogenated starch hydrolysate, natural moisturization factor, PEG-15 butanediol, polyglyceryl sorbitol, sodium and potassium salts of pyrollidone carboxylic acid, sodium glucuronate, trehalose and urea.

[0057] Skin anti-hyperpigmentation agents suitable for use in compositions of the invention include natural botanical agents derived from plant materials (such as Arctostaphylos

[0058] patula and Arctostaphylos viscida extracts, Emblica officinalis extract, Mitracarpus

[0059] scaber extract, Uva ursi (bearberry) extract, Morus bombycis (mulberry) extract, Morus alba (white mulberry) extract, Broussonetia papyrifera (paper mulberry) extract, licorice extract, acerola cherry extract, Chlorella vulgaris extract, Aloe ferrox extract and Rumex occidentalis extract); synthetic or natural sugar amines (such as glucosamine, N-acetyl glucosamine, glucosamine sulfate, mannosamine, N-acetyl mannosamine, galactosamine, N-acetyl galactosamine and their hydrochloride salts); retinoids (such as retinol, retinal, retinoic acid and C2-20 esters of retinol such as retinyl palmitate, retinyl acetate, retinyl propionate, retinyl linoleate and retinyl oleate); kojic acid and C2-20 esters thereof (such as kojic acid monobutyrate, kojic acid monocaprate, kojic acid monopalmitate, kojic acid monostearate and kojic acid monobenzoate); hydroquinone, hydroquinone monomethyl ether, hydroquinone monoethyl ether, hydroquinone monobenzyl ether, a and p-arbutin, deoxyarbutin (4-[(tetrahydro-2H-pyran-2-yl)oxy]phenol), mequinol (4-hydroxyanisole), glutathione, cysteine, N-acetyl-L-cysteine, azelaic acid, magnesium ascorbyl phosphate, sodium ascorbyl phosphate, peroxides (such as hydrogen peroxide, zinc peroxide, sodium peroxide and benzoyl peroxide); 3-aminotyrosine, glycyrrhizinic acid and 4-substituted resorcinol derivatives (such as 4-methyl resorcinol, 4-ethyl resorcinol, 4-propyl resorcinol, 4-isopropyl resorcinol, 4-butyl resorcinol, 4-pentyl resorcinol, 4-hexyl resorcinol, 4-heptyl resorcinol, 4-octyl resorcinol, 4-nonyl resorcinol, 4-decyl resorcinol, 4- undecyl resorcinol, 4-dodecyl resorcinol, 4-cyclopentyl resorcinol, 4-cyclohexyl resorcinol, 4-cycloheptyl resorcinol, and 4-cyclooctyl resorcinol).

[0060] Sunscreens suitable for use in compositions of the invention protect the skin from ultraviolet (UV) solar radiation falling within both the UVB region (between 290nm to 320 nm wavelengths) and the UVA region (between 320nm and 400nm wavelengths). Examples of sunscreens include methoxycinnamate derivatives (such as octyl methoxycinnamate and isoamyl methoxycinnamate); camphor derivatives (such as 4-methyl benzylidene camphor, camphor benzalkonium methosulfate, and terephthalylidene dicamphor sulfonic acid); salicylate derivatives (such as octyl salicylate and homosalate); sulfonic acid derivatives (such as phenylbenzimidazole sulfonic acid); benzone derivatives (such as dioxybenzone, sulisobenzone, and oxybenzone); benzoic acid derivatives (such as aminobenzoic acid and octyldimethyl para-amino benzoic acid); octocrylene, diethylhexyl butamido triazone, octyl triazone, butyl methoxydi benzoyl methane, drometrizole trisiloxane, menthyl anthranilate and inorganic UV-absorbing particles (such as zinc oxide and titanium dioxide).

[0061] Anti-irritants suitable for use in compositions of the invention include allantoin, aloe vera, a- bisabolol, caffeine, chamomile extract, Cola nitada extract, cucumber extract, dipotassium glycyrrhizinate, glycyrrhizic acid, green tea extract, lecithin or hydrogenated lecithin, licorice extract, Avena sativa (oat) meal extract, tea tree oil, salicylic acid, acetylsalicylic acid, strontium acetate, strontium chloride, strontium nitrate, fatty acids with anti-irritant properties (such as linoleic acid and linolenic acid) and aromatic aldehydes with anti-irritant properties (such as 4-methoxy benzaldehyde, 4-ethoxy benzaldehyde, 4-butoxy benzaldehyde and 4-pentoxy benzaldehyde).

[0062] Exfoliating agents suitable for use in compositions of the invention include benzoyl peroxide, benzoic acid, 3-hydroxy benzoic acid, salicylic acid, acetic acid, trichloroacetic acid, 1-pyrrolidone-5-carboxylic acid, a-hydroxy acids (such as glycolic acid, lactic acid, malic acid, tartaric acid, and citric acid); p-hydroxy acids (such as p-hydroxybutyric acid); a-keto acids (such as pyruvic acid, 2-oxopropanoic acid, 2-oxobutanoic acid and 2-oxopentanoic acid); and oxa acids (such as 3,6,9-trioxaundecanedioic acid).

[0063] Mixtures of any of the above-described materials may also be used. Functional

[0064] Topical skin care compositions of the invention may include additional functional ingredients (for improving the physical and / or aesthetic characteristics of the composition).

[0065] Examples of additional functional ingredients which are suitable for use in compositions of the invention may include water soluble or colloidally water soluble polymeric thickening agents (such as hydroxyethyl cellulose, methyl cellulose, hydroxypropyl methyl cellulose, polyquaternium-10, carrageenan, guar gum, hydroxypropyl guar gum, xanthan gum, polyvinylalcohol, acrylic acid / ethyl acrylate copolymers, carboxyvinyl polymers, cross-linked polyacrylate polymers and polyacrylamide polymers); structurant clays (such as magnesium aluminum silicate, attapulgite, bentonite, montmorillonite and hectorite); inorganic pigments (such as titanium oxide, zirconium oxide, cerium oxide zinc oxide, iron oxide, chromium oxide and ferric blue); organic pigments (such as carbon black and barium, strontium, calcium, and aluminium lakes); pearlescent agents (such as mica coated with titanium oxide and / or iron oxide); dyes, preservatives (such as disodium EDTA, benzyl alcohol, methyl paraben, phenoxyethanol, propylparaben, ethylparaben, butylparaben and isobutylparaben); pH adjusters and fragrances.

[0066] Mixtures of any of the above-described materials may also be used.

[0067] Packaging and Use

[0068] The above-described topical skin care composition of the invention may be packaged in a suitable container to suit its viscosity and intended use by the consumer. For example, a lotion or a cream can be packaged in a bottle or a roll-ball applicator, or a propellant-driven aerosol device or a container fitted with a pump suitable for finger operation. When the composition is a cream, it can simply be stored in a non-deformable bottle or squeeze container, such as a tube or a lidded jar.

[0069] The composition is suitably applied to the skin at the rate of one or two applications per day. Generally, an amount corresponding to about 1 to 2 ml of the composition per application is applied uniformly over the area of treatment twice daily for a period of at least 7 (seven) days, more preferably at least 30 (thirty) days.

[0070] The invention will be further illustrated by the following, non-limiting Examples. EXAMPLES

[0071] A Minimum Inhibitory Concentration (MIC) test was carried out to evaluate the antimicrobial efficacy of a combination of sapienic acid and 12-hydroxystearic acid against Staphylococcus aureus.

[0072] MIC is defined as the absolute lowest concentration of active that provides complete microbial growth inhibition as indicated by the colour change of Alamar blue under the tested conditions.

[0073] 2% (w / v) stock solutions of test actives were prepared with DMSO. 200pL of stock solution was dispensed into the first column of 96 well plates. 100pL from column 1 was serially diluted down to column 10 in 100pL sterile distilled water. Bacterial cultures were prepared at a titre of 1x108CFU / mL and following a 150x dilution into the corresponding growth medium, 100pL of bacteria / medium mix was added to test wells. The plates were inoculated at 37°C for 24 hours. Plates were visually checked to determine the visual MIC alongside an absorbance reading of 620nm taken before and after incubation to confirm the results. Growth was indicated by Alamar blue used at a concentration of 10% well volume. MIC was determined as the lowest concentration with a fluorescence value that matches or close to the fluorescence value of the negative control. This was obtained following incubation by subtracting the 0-hour read from the post- incubation read (24 hours).

[0074] In addition to the test actives, the following controls were used:

[0075] Positive control: 100pL of bacteria / medium mix and 100pL of sterile distilled water Negative control: 100pL of sterile medium and 100pL of sterile distilled water.

[0076] DMSO control: To assess the specific impact of DMSO on the viability of tested bacteria, DMSO diluted to 50% in sterile distilled water was used to match the DMSO concentrations used for solubilising the test actives.

[0077] The results are shown in the following Table 1: Table 1

[0078]

[0079] The results demonstrate that 12-hydroxystearic acid perse does not provide an appreciable antimicrobial activity against S. aureus. However, the admixture of 12-hydroxystearic acid with sapienic acid according to the invention provides a significant improvement in the MIC for S. aureus of sapienic acid.

[0080] The following Table 2 illustrates a skin care lotion according to the present invention.

[0081] Table 2

[0082]

Claims

Claims1. A topical skin care composition comprising:(i) one or more C16:1 fatty acids including sapienic acid, and(ii)12-hydroxystearic acid;in which the weight ratio of (i):(ii) ranges from 10:1 to 1:10, in which the total amount of C16:1 fatty acid ranges from 0.01 to 5% (by weight based on the total weight of the composition), and in which the amount of sapienic acid ranges from 0.01 to 5% (by weight based on the total weight of the composition), and in which the amount of 12- hydroxystearic acid ranges from 0.01 to 5% (by weight based on the total weight of the composition).

2. A composition according to claim 1, in which the weight ratio of C16:1 fatty acid to 12- hydroxystearic acid ranges from 1.5:1 to 1:1.5.

3. A composition according to claim 2, in in which the weight ratio of sapienic acid to 12- hydroxystearic acid ranges from 1.5:1 to 1:1.5.

4. A composition according to any one of claims 1 to 3, for use in the treatment of atopic dermatitis.

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