Cosmetic skin care methods

Abstract

A cosmetic skin care method for tailored release of free fatty acids on the skin of an individual, the method comprising the step of administering a mixture of triacylglycerols to a skin surface of the individual, in which the constituent triacylglycerols of the mixture are hydrolyzed at different rates on said skin surface by lipases originating from resident commensal Cutibacterium acnes bacteria on said skin surface.

Description

[0001] COSMETIC SKIN CARE METHODS

[0002] Field of the Invention

[0003] The present invention relates to cosmetic skin care methods for tailored release of free fatty acids by resident commensal microbes on the skin of an individual.

[0004] Background of the Invention

[0005] The skin is the largest organ of the body and provides the interface between the external environment and the host. While the skin has many important barrier functions, the two that are absolutely required for survival are the barrier to the movement of water and electrolytes (permeability barrier) and the barrier against invasive and toxic microbes (antimicrobial barrier).

[0006] The permeability barrier is localized to the outer layer of the epidermis, the stratum corneum (SC). The SC consists of corneocytes, keratinocytes that have undergone terminal differentiation, surrounded by a hydrophobic extracellular lipid matrix which provides the principal barrier to the transcutaneous movement of water and electrolytes.

[0007] The lipid matrix is composed primarily of ceramides, cholesterol, and free fatty acids. Free fatty acids are of key importance since they contribute to the structure of the lipid matrix as well as serving as building blocks for the more complex lipids of the lipid matrix such as ceramides. Fatty acids also contribute to the acidification of the SC, promoting its structural integrity and barrier function. They are mainly synthesized de novo by keratinocytes or taken up from the systemic circulation originating from dietary resources.

[0008] The free fatty acids found in the SC are mostly saturated and unbranched with hydrocarbon chain lengths ranging from 16 to 36 carbon atoms. Higher levels of C16 and C18 fatty acids, including unsaturated fatty acids (such as C18:1 and C18:2) have been reported in the more superficial layers of the SC. Studies show that these fatty acids may be more susceptible to removal during cleansing than other lipids such as ceramides. Because maintenance of the bilayer structure of the SC requires specific ratios of ceramide to free fatty acid to cholesterol, such preferential fatty acid removal could eventually result in barrier breakdown, dryness, and irritation. It is an object of the invention to provide cosmetic skin care methods for tailored release of free fatty acids. The methods may be used to deliver skin barrier benefits over a period of time by replenishing and maintaining free fatty acid levels in the SC.

[0009] Summary of the Invention

[0010] The invention provides a cosmetic skin care method for tailored release of free fatty acids on the skin of an individual, the method comprising the step of administering a mixture of triacylglycerols to a skin surface of the individual, in which the constituent triacylglycerols of the mixture are hydrolyzed at different rates on said skin surface by lipases originating from resident commensal Cutibacterium acnes bacteria on said skin surface.

[0011] Detailed Description of the Invention

[0012] As used herein, “cosmetic skin care” means the non-therapeutic regulation and / or improvement of one or more cosmetic qualities of the skin, as opposed to curing, treating, or preventing a disease or disorder. Accordingly, 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.

[0013] Examples of cosmetic skin care benefits in the context of this invention include providing a smoother, more even texture; improving the elasticity or resiliency of the skin; improving the firmness of the skin; improving the hydration status or moisturization of the skin; improving skin barrier properties; and reducing the appearance of redness or skin blotches.

[0014] As used herein, “skin” is understood as the layers which comprise it, from the uppermost layer or stratum corneum to the lowermost layer or hypodermis, both inclusive. These layers are composed of different types of cells such as keratinocytes, fibroblasts, melanocytes, mastocytes, neurons, and adipocytes. The term “skin” also comprises the scalp. Preferably the term “skin” as used herein denotes the epidermis and more preferably the stratum corneum of the epidermis.

[0015] As used herein, the term “resident commensal” denotes a microbe which can normally be found on healthy human skin, whose interactions on the skin are either neutral or beneficial, and which are permanent inhabitants on the surface of the skin, the stratum corneum and within the outer layer of the epidermis and the deeper crevices of the skin and hair follicles. Microbial colonization is differentially shaped by the physiological and topological variation of the skin, and varies systematically among different skin habitats, such as between dry, moist, and sebaceous skin. Resident commensal microbes are characterized in that they can grow and multiply on the skin without invading or damaging the skin tissue. Another characteristic of these microbes is that washing does not easily remove them in deeper skin regions.

[0016] The members of the species C. acnes have been classified into three major genetic lineages, (phylotypes, I, II, and III) based on serological agglutination tests, cell wall sugar analysis, fatty acid profiles, and morphology. These have been assigned to three subspecies as follows: phylotype I as C. acnes subsp. acnes, phylotype II as C. acnes subsp. defendens, and phylotype III as C. acnes subsp. elongatum. Based on 16S rRNA gene analysis, C. acnes strains have also been classified into multiple ribotypes (RTs).

[0017] Studies indicate that C. acnes subspecies acnes (phylotype I) strains (RT1 , RT3, RT4, RT5, and RT8) are more often associated with acne. By contrast, C. acnes subspecies defendens (phylotype II) strains (RT2 and RT6) are more frequently found on healthy skin, particular the RT6 subgroup which has been found to be 99% associated with healthy skin.

[0018] C. acnes subsp. defendens (phylotype II) strains associated with healthy skin display a number of strain specific characteristics at the genetic, transcriptional, and translational levels, which may account for their commensal phenotype and non-association with acne. Elements that may be used to characterise such strains include the presence of a complete set of the CRISPR / Cas genes. Also, C. acnes subsp. defendens (phylotype II) strains associated with healthy skin secrete only low levels of porphyrins and carry a deoR gene that represses porphyrin biosynthesis. There is growing evidence that the colonization of such strains on the skin is not only non-associated with acne but can actually confer benefits to the skin, for example through modulation of immune cell activity and secretion of protective substances.

[0019] The skin can be subdivided into different ecological niches based on physio-chemical properties such as density of sebaceous and sweat glands, level of moisture and oxygen tension. In healthy individuals, C. acnes colonizes these environments at different densities.

[0020] In the method of the invention, the mixture of triacylglycerols may suitably be administered to skin surfaces with the highest density of C. acnes, typically sebaceous sites such as the face. A skin surface may also be treated to enhance growth and / or activity of C. acnes, either prior to or together with the administration of the mixture of triacylglycerols. For example, the skin surface may be treated with probiotics, i.e. live cultures of selected commensal strains of C. acnes bacteria, or a lysate or supernatant thereof. Alternatively, or additionally, the skin surface may be treated with a prebiotic which can support the growth of commensal C. acnes bacteria.

[0021] Preferred prebiotics in the context of this invention have a specific stimulatory impact on the growth of commensal C. acnes bacteria, especially C. acnes subsp defendens (phylotype II) strains which are associated with healthy skin.

[0022] Bacterial growth may be measured by available means and methods for determining the number of cells and / or colonies, for example by staining with an appropriate dye and / or optical means such as densitometry and counting the cells / colonies under the microscope.

[0023] An example of a preferred prebiotic which has been observed to have a specific stimulatory impact on the growth of commensal C. acnes bacteria, especially C. acnes subsp defendens (phylotype II) strains which are associated with healthy skin, is erythritol ((2R,3S)-butan-1 , 2,3,4- tetrol). Studies show that erythritol can support the growth of C. acnes ribotypes (RTs) associated with healthy skin (RT2 and RT6) whilst inhibiting, or not promoting, the growth of C. acnes RTs associated with acne (RT1, RT3, RT4, RT5, and RT8).

[0024] Mixtures of any of the above-described materials may also be used.

[0025] According to the method of the invention, a mixture of triacylglycerols is administered to a skin surface. The constituent triacylglycerols of the mixture are hydrolyzed at different rates by the C. acnes bacteria.

[0026] Preferably the mixture of triacylglycerols is a mixture of (i) one or more saturated homotriacylglycerols of general formula (I):

[0027] RCOO-CH2CH(-OOCR)CH2-OOCR (I) in which each R is the same and represents a saturated alkyl group having 16, 18 or 20 carbon atoms, more preferably a saturated n-alkyl group having 16 or 18 carbon atoms; and (ii) one or more unsaturated homotriacylglycerols of general formula (II):

[0028] R’COO-CH2CH(-OOCR’)CH2-OOCR’ (II) in which each R’ is the same and represents a monounsaturated or diunsaturated alkyl group having 16, 18 or 20 carbon atoms, more preferably a monounsaturated n-alkyl group having 16 or 18 carbon atoms, most preferably a c / s-6- or a c / s-9-monounsaturated n-alkyl group having 16 or 18 carbon atoms.

[0029] A suitable example of a mixture of triacylglycerols which are hydrolyzed at different rates is a mixture containing from 10 to 90% (by weight based on the total weight of the mixture) triolein and / or trisapienate (cis-6-hexadecenoic triglyceride), preferably triolein and trisapienate, with the balance being made up of tripalmitin and / or tristearin, preferably tripalmitin and tristearin. The C. acnes bacteria hydrolyze the triolein and the trisapienate faster than the tripalmitin and the tristearin. Therefore, this mixture may be used to provide short term and longer-term delivery of free fatty acid to the skin.

[0030] The weight ratio of (triolein and trisapienate) to (tripalmitin and tristearin) in the mixture of triacylglycerols will determine the release profile of free fatty acid to the skin. This ratio can be adjusted according to the desired skin benefits as well as the individual’s skin type and skin condition. For an optimum balance of short term and longer-term delivery of free fatty acid to the skin, the weight ratio of (triolein and trisapienate) to (tripalmitin and tristearin) will typically range from about 3:1 to about 1:3 and preferably ranges from about 2:1 to about 1:2. An example of a suitable mixture of triacylglycerols for use in the invention is a mixture of trisapienate, triolein, tripalmitin and tristearin at a weight ratio from about 1 : 1 : 1 :1. A suitable composition which may be used to carry out the method of this invention comprises, in a cosmetically acceptable vehicle, from 0.01 to 10%, preferably from 0.1 to 5% (by weight based on the total weight of the composition) of a mixture of triacylglycerols which is a mixture of trisapienate, triolein, tripalmitin and tristearin at a weight ratio from about 1 : 1 : 1 : 1.

[0031] In addition to the mixture of triacylglycerols described above, the composition may also include, if desired, one or more ingredients to enhance growth and / or activity of C. acnes, such as the probiotics and / or prebiotics as described above.

[0032] For example, the composition may include from 0.01 to 10%, preferably from 0.1 to 5% (by weight based on the total weight of the composition) of a prebiotic having a specific stimulatory impact on the growth of commensal C. acnes subsp defendens (phylotype II) strains, for example erythritol.

[0033] Alternatively, the probiotic and / or prebiotic, if used, may be administered to the desired skin surface in a separate pretreatment step.

[0034] The term “cosmetically acceptable” in the context of this invention means that the vehicle is suitable for topical application to the skin, has good aesthetic properties and will not cause any ingredient compatibility, safety, or toxicity concerns.

[0035] Suitable cosmetically acceptable vehicles 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.

[0036] 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.

[0037] 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. Compositions in the form of an emulsion, and suitable for use in carrying out the method of this invention, typically have an oil phase containing one or more cosmetically acceptable fatty materials which may be liquid or solid at room temperature (25°C).

[0038] In addition to the mixture of triacylglycerols described above, 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 polyols 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); fatty acids containing from 8 to 30 carbon atoms, (such as stearic acid, lauric acid, palmitic acid and oleic acid); vegetable fats (such as cocoa butter, coconut oil, palm oil and shea butter); petroleum-based, natural and 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).

[0039] Compositions in the form of an emulsion, and suitable for use in carrying out the method of this invention, typically have an aqueous phase, which 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. Compositions in the form of an emulsion, and suitable for use in carrying out the method of this invention, generally include surface active ingredients, such as emulsifiers and solubilizers, to enable two or more immiscible components to be combined homogeneously and to help stabilize 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.

[0040] Compositions for use in carrying out the method of this invention may also be formulated in a single-phase carrier such as a hydrophobic or hydrophilic liquid. Suitable hydrophobic liquid carriers include liquid polyorganosiloxanes, mineral oils, hydrogenated polyisobutene, polydecene, paraffins and isoparaffins of at least 10 carbon atoms, aliphatic or aromatic ester oils (such as isopropyl myristate, lauryl myristate, isopropyl palmitate, diisopropyl sebacate, diisopropyl adipate and Ci2 to C15 alkyl benzoates), polyglycol ethers (such as polyglycol butanol ethers) and mixtures thereof. Suitable hydrophilic liquid carriers include water, monohydric or polyhydric aliphatic alcohols having 2 to 8, preferably 2 or 3 carbon atoms (such as ethanol and isopropanol, oligoglycol ethers having 2 to 5 repeat units (such as dipropylene glycol) and mixtures thereof.

[0041] Liquid form compositions for use in carrying out the method of this invention may be thickened, for example using one or more water soluble or colloidally water-soluble polymeric thickening agents. Suitable water soluble or colloidally water-soluble polymeric thickening agents include 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.

[0042] Solid form compositions for use in carrying out the method of this invention, such as gels and sticks, generally include one or more structurants, in an amount ranging from about 1 % to about 35% (by weight based on the total weight of the composition), depending upon the desired product consistency. Examples of structurants include fatty acid gelling agents selected from saturated fatty acids or hydroxy acids containing from about 8 to 30 carbon atoms and their salts, esters or amides (such as sodium and potassium stearate, 12- hydroxy stearic acid, esters of 12-hydroxystearic acid and amides of 12-hydroxystearic acid); saturated, unsubstituted monohydric fatty alcohols containing from about 8 to 30 carbon atoms (such as cetyl alcohol, myristyl alcohol and stearyl alcohol); acyl amino acid derivatives such as N-lauroyl-L-glutamic acid di-n-butylamide; amide derivatives of di or tribasic carboxylic acids such as alkyl N,N' dialkylsuccinimide; inorganic particulate thickening agents selected from siliceous and alumino- siliceous materials (such as fumed silicas, bentonites, hectorites, colloidal magnesium aluminum silicates and organoclays such as stearalkonium bentonite, disteardimonium hectorite, quaternium 90-bentonite), quaternium-18 bentonite and quaternium-18 hectorite); and petroleum-based, natural and synthetic waxes (such as lanolin wax, beeswax, carnauba wax, candelilla wax, castor wax, montan wax, paraffin wax, lignite wax, microcrystalline waxes, ceresin, ozokerite, polymethylene and polyethylene waxes).

[0043] Combinations of any of the above-described materials or product forms may also be used.

[0044] Compositions for use in carrying out the method of this invention may include additional skin care actives for improving the physical and / or aesthetic characteristics of the skin.

[0045] Examples of additional skin care actives include vitamins, minerals and / or antioxidants, skin anti-hyperpigmentation agents, sunscreens, anti-irritants, exfoliating agents, and mixtures thereof.

[0046] Suitable vitamins, minerals and / or antioxidants 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 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.

[0047] Suitable skin anti-hyperpigmentation agents include natural botanical agents derived from plant materials (such as Arctostaphylos patula and Arctostaphylos viscida extracts, Emblica officinalis extract, Mitracarpus 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).

[0048] Suitable sunscreens 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 methoxydibenzoyl methane, drometrizole trisiloxane, menthyl anthranilate and inorganic UV-absorbing particles (such as zinc oxide and titanium dioxide).

[0049] Suitable anti-irritants 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).

[0050] Suitable exfoliating agents 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).

[0051] Mixtures of any of the above-described materials may also be used.

[0052] Compositions for use in carrying out the method of this invention may also include additional functional ingredients for improving the physical and / or aesthetic characteristics of the composition.

[0053] Examples of suitable additional functional ingredients 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 aluminum 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.

[0054] Mixtures of any of the above-described materials may also be used.

[0055] Suitably, in carrying out the method of this invention, the composition as defined above is applied to the desired region of treatment of the skin. Generally, an amount corresponding to about 1 to 2 ml of the composition is applied uniformly over the desired region of treatment of the skin, once or twice daily for a period of at least 7 (seven) days, preferably at least 30 (thirty) days.

[0056] Compositions for use in carrying out the method of this 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.

[0057] The invention will be further illustrated by the following, non-limiting Examples.

[0058] EXAMPLES

[0059] A study was conducted to investigate the contribution of Cutibacterium acnes (ATCC 6919) lipases to triglyceride hydrolysis and fatty acid release by LC-MS / MS in a targeted mass- spectrometry (TQD). A triglycerides mix was prepared including trisapienate, tripalmitin, tristearin, triolein and the amount of the respective fatty acid (sapienic acid, palmitic acid, stearic acid, oleic acid) released was measured.

[0060] Test inoculum was prepared in recommended growth media for 24 hours at 37°C under anaerobic conditions. Inoculum was centrifuged and 40 ml supernatant (liquid media) containing Cutibacterium acnes lipases transferred to new vial with 3ml of 0.2% triglycerides mix in glycerol (140pg / ml).

[0061] To measure the triglyceride hydrolysis overtime, an aliquot of 1ml was collected after different incubation time (TO, 1 h, 2h, 4h, 5h, 24h, 48h, 5 days and 9 days). After the incubation period, lipids were extracted from the samples by adding a combination of methanol: chloroform (1 :2) to each sample. The amount of triglyceride hydrolysis and fatty acid released was quantified by LC- MS / MS in a targeted mass-spectrometry (TQD), using known standards as reference.

[0062] The following Table 1 shows the percentage of triglycerides hydrolysis and fatty acid release by Cutibacterium acnes lipases.

[0063] Table 1

[0064] It can be seen from the results that C. acnes lipases efficiently released sapienic acid from trisapienate, palmitic acid from tripalmitin, stearic acid from tristearin and oleic acid from triolein, however the triglycerides’ hydrolysis happens at different rates. Therefore, this represents a route for the controlled release of free fatty acids through bacterial hydrolysis of triglycerides.

[0065] The following Table illustrates a skin care lotion for application to skin for tailored release of free fatty acids according to the present invention.

[0066] (1)Mixture oftrisapienate, triolein, tripalmitin and tristearin at a weight ratio of 1: 1: 1: 1.

Claims

Claims1. A composition for use in a method for tailored release of free fatty acids on the skin of an individual, the composition comprising, in a cosmetically acceptable vehicle: (i) from 0.01 to 10% (by weight based on the total weight of the composition) of a mixture of triacylglycerols which is a mixture containing from 10 to 90% (by weight based on the total weight of the mixture) triolein and trisapienate, with the balance being made up of tripalmitin and tristearin ; and (ii) optionally, from 0.01 to 10% (by weight based on the total weight of the composition) of a prebiotic having a specific stimulatory impact on the growth of commensal C. acnes bacteria.

2. A composition according to claim 1, in which the prebiotic is erythritol.

3. A composition according to claim 1 or claim 2, in which the weight ratio of (triolein and trisapienate) to (tripalmitin and tristearin) in the mixture of triacylglycerols ranges from 3:1 to 1 :3.

4. A composition according to claim 3 in which the mixture of triacylglycerols is a mixture of trisapienate, triolein, tripalmitin and tristearin at a weight ratio from about 1 : 1 :1 : 1.

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