Skin care benefits from cosmetic compositions

Abstract

The non-therapeutic use of a water-in-oil emulsion stick composition comprising a humectant for boosting the natural level of ceramides in the human skin.

Description

[0001] Skin Care benefits from Cosmetic Compositions

[0002] Field of Invention

[0003] The invention is concerned with the use of cosmetic compositions for giving skin care benefits; in particular, it is concerned with boosting the natural level of ceramides present within the skin.

[0004] Background

[0005] There are numerous cosmetic treatments available for giving skin care benefits. Many of these focus on skin hydration and the prevention of dryness. In recent years, there has been a particular interest in augmenting the skin’s content of ceramides present within the skin. Ceramides are a group of lipids naturally present with human skin that help seal in moisture of protect the skin’s natural barrier.

[0006] Ceramides are present in a wide range of skin care products, including many sold under the CeraVe brand, such as CeraVe Moisturising Lotion. They are also present in cosmetic products sold under the Dove brand, such as Dove Ceramide Intense Repair conditioner. They have also been disclosed in numerous patent publications concerning cosmetic compositions.

[0007] WO 2017 / 116950 A1 (L’Oreal, 2017) discloses cosmetic compositions in the form of an emulsion comprising at least one ceramide, cholesterol and oils.

[0008] EP 3,741,353 B1 (LG Household & Health Care Ltd., 2014) discloses cosmetic compositions comprising ceramide-accommodating particles prepared by mixing an oil phase part comprising a ceramide and phytosphingosine with an aqueous phase part.

[0009] US 11896688 BB (Kao, 2024) discloses water-in-oil emulsion compositions comprising a ceramide and other ingredients common to cosmetic compositions. The present invention is concerned with the use of cosmetic compositions for increasing the natural level of ceramides within the skin, i.e., without the need for topical application of ceramides themselves. The present invention is particularly concerned with the use of water-in-oil emulsions stick compositions for the above purpose, especially when the composition is a deodorant or antiperspirant composition.

[0010] Water-in-oil emulsion sticks are a well-known cosmetic composition format. This format has been used for antiperspirant stick compositions and other cosmetic sticks.

[0011] US 6,139,824 (L’Oreal, 2000) discloses water-in-oil emulsion sticks comprising potassium alum in the aqueous phase and in which the oil phase is gelled with polyethylene.

[0012] WO 2001 / 85119 (Unilever, 2001) discloses antiperspirant water-in-oil emulsions in which the oil phase is structured with an ester wax.

[0013] WO 2022 / 013101 (Unilever, 2022) discloses solid water-in-oil emulsion stick compositions comprising an aluminium sesquichlorohydrate antiperspirant active, an oil phase, an emulsifier, a solidifying agent and a polyol selected from glycerol, propylene glycol and selected PEG oligomers.

[0014] Summary of Invention

[0015] The invention is concerned with the use of water-in-oil emulsion stick compositions for boosting the natural level of ceramides within the human skin.

[0016] It is an object of the invention to boost the natural level of ceramides within the skin. It is a particular object of the invention to boost their level within the skin after the skin has been stressed, whether by physical or chemical means. This may alternatively be described as a means to help the skin recover its natural ceramide levels after they have been depleted by stress.

[0017] Physical stress to the skin may be caused by abrasive treatments, in particular shaving, which commonly causes redness or soreness. Another cause of physical stress is chafing, when the skins rubs against itself or clothing. Skin-to-skin chafing may occur in the underarms or in other areas of the body, such as the inner thighs or buttocks. Hence, the invention may be of particular value when the composition is suitable for application to the whole body; for example, a whole body deodorant or antiperspirant.

[0018] Chemical stress to the skin may be caused by irritant chemical application, including the application of surfactants, in particular anionic surfactants. Other ingredients that can lead to chemical stress include allergens and sensitisers.

[0019] It is a particular object to boost the natural level of ceramides within the skin by topical application of a water-in-oil emulsion stick composition comprising a humectant.

[0020] In certain embodiments of the invention, it is an object to additionally provide deodorancy benefits to the human body.

[0021] In certain embodiments of the invention, it is an object to additionally provide antiperspirancy benefits to the human body.

[0022] In a first aspect of the invention, there is provided the use of a water-in-oil emulsion stick composition comprising a humectant for boosting the natural level of ceramides in the human skin.

[0023] In a second aspect of the invention, there is provided the use of a composition as described in the first aspect of the invention for additionally boosting the level of another selected benefit agent within the skin, the benefit agent being selected from hyaluronic acid and caspases.

[0024] 11 n a third aspect of the invention, there is provided the use of a composition as described in the first or second aspect of the invention for additionally deodorising the human skin.

[0025] In a fourth aspect of the invention, there is provided the use of a composition as described in the first, second or third aspect of the invention for additionally reducing perspiration on the surface of the human skin. Detailed

[0026] The stratum corneum (SC) is the uppermost layer of the skin, composed of from 5 to 30 cellular layers. The main unit of the SC is the corneocyte, a cell filled by a hydrophilic mass of keratin filaments and surrounded by a lipid-rich extracellular matrix. One of the most important intercellular lipids surrounding the corneocytes are ceramides, representing 50% of the total lipidic mass of the SC. Intercellular lipids, including ceramides, help to maintain skin hydration. In addition, they represent a physical barrier protecting the epidermis. Hence, ceramides are a significant skin benefit agent.

[0027] Hyaluronic acid (HA) is a skin benefit agent which is a polymer of disaccharides, themselves composed of D-glucuronic acid and D-N-acetylglucosamine, linked via alternating p-1 ,4 and p-1 ,3 glycosidic bonds. HA is a major component of skin, where it is involved in several processes, including tissue hydration and repair and fibroblast proliferation. HA is a key component of the extracellular matrix helping to maintain the integrity of the epidermis and the dermis.

[0028] Caspases are a family of skin benefit agents that participate in apoptosis, a natural biological process of self-destruction of cells. Caspase 14 is the only activated caspase found in the epidermal barrier and is cleaved during the terminal differentiation and cell death of keratinocytes which results in improved skin barrier formation.

[0029] In preferred embodiments, the present invention boosts the natural level of hyaluronic acid and ceramides in the human skin.

[0030] In particularly preferred embodiments, the present invention boosts the natural level of ceramides, hyaluronic acid and caspases, in particular Caspase 14, in the human skin.

[0031] Herein, the word “boosting” is intended to mean increasing in amount or concentration. In preferred embodiments, the boosting is by an amount significant at the 95% level of confidence. This is the case whether the “boosting” referred to is to the level of ceramides, hyaluronic acid, caspases, or any combination thereof. Herein, features expressed as “preferred” with regard to a particular aspect of the invention should be understood to be preferred with regard to each aspect of the invention (likewise, features expressed as “more preferred”, “particularly preferred” or “most preferred”). “Preferred” features typically aid the delivery of one or more of the objects of the invention.

[0032] Herein, preferred features of the invention are particularly preferred when used in combination with other preferred features (likewise, features expressed as “more preferred”, “particularly preferred” or “most preferred”).

[0033] Herein, “ambient conditions” refer to 20°C and 1 atmosphere pressure, unless otherwise indicated.

[0034] Herein, “water insoluble” refers to materials having a solubility in water of less than 0.1 g / 100g, under ambient conditions.

[0035] Herein, all percentages, ratios and amounts are by weight, unless otherwise indicated.

[0036] Herein, amounts and concentrations of ingredients are percentages by weight of the total composition, unless otherwise indicated.

[0037] Herein, references to amounts of components such as “deodorant active” or “rheological modifier” relate to the total amount of such components present in the composition.

[0038] Herein, the word “comprising” is intended to mean “including” but not necessarily “consisting of’, i.e. , it is non-exhaustive.

[0039] Herein, all uses, methods and compositions should be understood to mean cosmetic uses, methods and compositions; that is to say, non-therapeutic uses, methods and compositions. Herein, references to the dermis refer in particular to the papillary dermis, the top level of the dermis located immediately below the epidermis.

[0040] Herein, Caspase 14 is used as representative of the wider class of cysteine proteases known as caspases. Caspases are natural and essential skin enzymes involved in skin barrier repair and / or regeneration. Caspases benefit skin condition by their presence and action.

[0041] In accordance with the invention, the water-in-oil emulsion stick composition used to boost ceramide levels can do so without itself comprising ceramides. Indeed, it is preferred that compositions used in the invention exclude, i.e. are free from, ceramides.

[0042] In aspects of the invention wherein hyaluronic acid levels are boosted, the water-in-oil emulsion stick composition can be effective without itself comprising hyaluronic acid. Indeed, it is preferred that compositions used in the invention exclude, i.e. are free from, hyaluronic acid.

[0043] In aspects of the invention wherein caspases are boosted, the water-in-oil emulsion stick composition can be effective without itself comprising caspases. Indeed, it is preferred that compositions used in the invention exclude, i.e. are free from, caspases.

[0044] The water-in-oil emulsion stick composition is preferably an antiperspirant stick, i.e. a stick comprising an antiperspirant active that leads to a reduction in perspiration on the surface of the human body following topical application.

[0045] Stick compositions used in the invention are preferably solidified with a structuring agent, typically giving a water-in-oil emulsion stick.

[0046] Herein, “solidified” refers to a state of matter incapable of flow at a temperature of 25°C and a pressure of 1 atmosphere.

[0047] The structuring agent employed in emulsion sticks used in the invention may be a single structurant or a mixture of structurants. The amount of the structuring agent used is preferably from 5%, more preferably from 7% and most preferably from 8%. The upper amount is preferably up to 25%, more preferably up to 20% and most preferably up to 15%. The preferred ranges of solidifying agent may be selected from any of the lower and upper amounts indicated in this paragraph.

[0048] The structuring agent mentioned immediately above is preferably a wax. More preferably the structuring agent is a polyolefin wax, in particular a polyethylene wax. Such waxes are typically synthetic waxes, i.e. waxes synthesised from olefins in the case of polyolefin waxes and waxes synthesised from ethylene in the case of polyethylene waxes.

[0049] The aqueous phase of water-in-oil emulsions used in accordance with the invention typically comprises from 30 to 68% of the total composition. Preferably, it comprises from 40 to 65% and more preferably from 45 to 60% of the total composition.

[0050] A preferred additional component of compositions used in accordance with the invention is an antiperspirant active. Such an active is preferably an astringent aluminium salt or aluminium-zirconium salt. Such salts are typically dissolved in the aqueous disperse phase of the emulsion and are commonly present in emulsion sticks used in accordance with the invention.

[0051] We have found that it is very difficult to formulate hyaluronic acid with antiperspirant actives, due incompatibility issues. Hence, the use of a water-in-oil emulsion stick composition to boost hyaluronic acid levels in addition to ceramide levels, when applied together with an antiperspirant active is particularly innovative. This is particularly true when an antiperspirant active comprising aluminium is involved, as is the case with most commercial antiperspirant compositions.

[0052] A preferred antiperspirant active is aluminium sesquichlorohydrate (ASCH). ASCH has the chemical formula of AI2OH4.4CI1.6 to AI2OH4.9CI1.1. Most commercial ASCH samples are of chemical formula AI2OH4.7CI1.3 to AI2OH4.9CI1.1 and it is particularly preferred to use actives of this formula. Particularly preferred AP actives comprise calcium and particularly preferred actives also comprise an amino acid, in particular glycine. Such actives are described in WO 2014 / 187685 (Unilever, 2014). The calcium is typically added in the form of calcium chloride. It is especially preferred that such actives are calcium-activated ASCH salts.

[0053] AP actives that are complexes with glycine are preferred, particularly when they also comprise calcium and / or are activated by calcium.

[0054] In certain especially preferred embodiments, a calcium-activated ASCH glycine complex is used.

[0055] The proportion of antiperspirant salt is calculated excluding the weight of any water of hydration but including any complexing agent that may be present, such as glycine and any activating agent, such as calcium chloride.

[0056] The weight concentration of the antiperspirant salt in the aqueous phase is commonly not higher than 50% and is advantageously at least 10%. In preferred embodiments its weight concentration is from 15 to 40% and in more preferred embodiments it is from 20 to 30%.

[0057] The weight of antiperspirant salt in the entire composition is usually at least 6% and is commonly up to 30%. The range of antiperspirant salt concentration for the composition is preferably from 8% to 25% and more preferably from 10 to 20%.

[0058] In preferred embodiments, the water-in-oil emulsion stick composition is used for boosting hyaluronic acid levels in the human skin and delivering an antiperspirancy benefit, i.e. , a reduction in perspiration on the surface of the human skin.

[0059] An essential component in compositions used in the invention is a humectant, preferably selected from glycerol and / or a PEG oligomer of weight average molecular weight of from 180 to 420. Glycerol is an especially preferred humectant. The humectant may enhance the skin care properties of the composition. The humectant is present at a preferred level of from 1 to 25%, more preferably from 5 to 22% and most preferably from 10 to 20%, these levels being particularly relevant when the humectant is glycerol.

[0060] A preferred additional component in compositions used in the invention is a water soluble vitamin, such as Vitamin B3 or niacinamide. Such vitamins are present at a level at a preferred level of from 0.1 to 8%, more preferably from 0.5 to 6% and most preferably from 1 to 5% by weight of the total composition. Such vitamins may enhance the skin care properties of the composition.

[0061] A preferred additional component in compositions used in the invention is a fragrance oil, alternatively known as a perfume oil. The fragrance oil may comprise a single fragrance component or, more commonly, a plurality of fragrance components. Herein, fragrance oils impart an odour, preferably a pleasant odour, to the composition. Preferably, the fragrance oil imparts a pleasant odour to the surface of the human body the composition is applied to the same.

[0062] The amount of fragrance oil in the composition is preferably up to 3%, advantageously is at least 0.5% and particularly preferably from 0.8% to 2%.

[0063] In certain embodiments, it is preferred to include an oil, other than a fragrance oil, that has a relatively low viscosity, by which is meant less 250 cS (mm2.s’1). Such oils, termed “non-fragrance oils”, can improve the sensory properties of the composition on application and can lead to other benefits such as emolliency.

[0064] Preferred non-fragrance oils are alkyl ether oils having a boiling point of above 100°C and especially above 150°C, including polyalkyleneglycol alkyl ethers. Such ethers desirably comprise between 10 and 20 ethylene glycol or propylene glycol units and the alkyl group commonly contains from 4 to 20 carbon atoms. The preferred ether oils include polypropylene glycol alkyl ethers such as PPG-14-butylether and PPG-15-stearyl ether.

[0065] Other preferred non-fragrance are triglyceride oils. The triglyceride oils commonly comprise the alkyl residues of aliphatic C?to Cis acids, the total number of carbon atoms being selected in conjunction with the extent of olefinic unsaturation and / or branching to enable the triglyceride to be liquid at 20°C. Particularly preferably, in the triglyceride oil the alkyl residues are linear Cis groups having one, two or three olefinic degrees of unsaturation, two or three being optionally conjugated, many of which are extractable from plants (or their synthetic analogues), including triglycerides of oleic acid, linoleic acid, conjugated linoleic acids, linolenic acid, petroselenic acid, ricinoleic acid, linolenelaidic acid, trans 7-octadecenoic acid, parinaric acid, pinolenic acid, punicic acid, petroselenic acid and stearidonic acid.

[0066] Suitable oils can include those derived from unsaturated Cis acids, including coriander seed oil, impatiens balsimina seed oil, parinarium laurinarium kernel fat oil, sabastiana brasilinensis seed oil, dehydrated castor seed oil, borage seed oil, evening primrose oil, aquilegia vulgaris oil, sunflower (seed) oil and safflower oil. Other suitable oils are obtainable from hemp, and maize corn oil. An especially preferred oil by virtue of its characteristics is sunflower (seed) oil.

[0067] Further suitable oils, that can also be emollient oils, comprise alkyl or alkyl-aryl ester oils having a boiling point of above 150°C (and a melting point of below 20°C). Such ester oils include oils containing one or two alkyl groups of 12 to 24 carbon atoms length, including isopropyl myristate, isopropyl palmitate and myristyl palmitate. Other nonvolatile ester oils include alkyl or aryl benzoates such C12-15 alkyl benzoate, for example Finsolv TN™ or Finsolv Sun™.

[0068] Other components that may be included in composition used in the invention include those described in the following paragraphs.

[0069] Wash-off agents may be included, often in an amount of up to 10%, to assist in the removal of the formulation from skin or clothing. Such wash-off agents are typically nonionic surfactants such as esters or ethers containing a Cs to C22 alkyl moiety and a hydrophilic moiety comprising a polyoxyalkylene group (POE or POP).

[0070] Skin-feel improvers (e.g. talc or finely divided high molecular weight polyethylene), may be included, typically in an amount from 1 up to 10%. An optional component is a preservative system, such as sodium benzoate / citric acid and / or an antioxidant such BHT (butyl hydroxy toluene), each typically in an amount of from 0.01 to 0.5%.

[0071] Examples

[0072] The following Examples are illustrative of the invention and non-limiting as to its scope.

[0073] The preparation of the Examples in Table 1 involved a preliminary step of ‘activating’ the ASCH with calcium chloride and glycine to give an “activated ASCH” (AASCH) solution. In this preliminary step, the ASCH, calcium chloride and glycine were heated together with the water for 2 hours at 87°C. The final solution comprised 27.0% ACH, 3.4% calcium chloride and 2.6% glycine.

[0074] The aqueous solution of AASCH prepared as described above was used to prepare Example P1 by methods known in the art. Example P1 had good solidity and stability.

[0075] The Example was tested in the following 3-day study. The results are indicated at the base of Table 1.

[0076] Human skin explants of average diameter 12 mm were prepared from tissue removed in an abdominoplasty procedure. The explants were kept in survival in BEM culture medium (BIO-EC’s bespoke Explant medium) at 37°C in a humid, 5% CO2 atmosphere.

[0077] On day 1 of the study, a selection of the explants were treated topically with a paper disk soaked with a 1.25% w / w aqueous solution of sodium dodecyl sulphate (SDS), to induce irritation stress in the explants. Doing this partially depletes ceramides in the epidermal barrier and increases the sensitivity of the explants to subsequent treatments. It also enables the subsequently applied treatments to be tested as to their ability to help skin recover from stress events. The paper disks were removed after 24 hours of contact and the products to be tested were applied immediately afterwards.

[0078] Example P1 was applied topically at 2 mg per 1 cm2explant and spread using a spatula. The product was applied both to explants that had been stressed with SLS as described above and explants that had not been so stressed. The culture medium was half renewed (1 ml) on day 1 and fully renewed (2 ml) on day 2. Control explants did not receive any treatment except the culture medium renewal.

[0079] On day 3 of the study, FFPE (formal-fixed paraffin-embedded) skin sections of the explants were prepared. These were sliced into 5 micron sections using a microtone.

[0080] Ceramide immunostaining was performed with an anti-ceramides monoclonal antibody (Glycobiotech, ref. MAB_0013, clone S58-9) diluted at 1 :400 in PBS, BSA 0.3% overnight at room temperature, with a biotin / streptavidin amplifying system and revealed by VIP (Vector laboratories, Ref. SK-4600), a substrate of peroxidase giving a violet stain once oxidised. The immunostaining was assessed by microscopical observation and semiquantified by image analysis as above.

[0081] Hyaluronic acid immunostaining of the FFPE sections was performed with a biotinylated hyaluronic acid binding protein (HABP, Amsbio ref. AMS.HKD.BC41) diluted at 1:400 in PBS, BSA 0.3% for 1 hour at room temperature, with a biotin / streptavidin amplifying system and revealed by VIP (Vector laboratories, Ref. SK-4600), a substrate of peroxidase giving a violet stain once oxidised. The immunostaining was assessed by microscopical observation and semi-quantified by image analysis using the software cellSens (Olympus).

[0082] Caspase 14 immunostaining was performed with a monoclonal anti-Caspase 14 antibody (Santa Cruz, ref. sc-48336, clone D-10) diluted at 1:400 in PBS, BSA 0.3% for 1 hour at room temperature using Vectastain Kit vector amplifying system streptavidin / biotin and revealed by VIP (Vector, Ref. SK-4600). The immunostaining was assessed by microscopical observation and semi-quantified by image analysis as above.

[0083] Samples from the explants were analysed and a comparison made between those treated with the Example indicated in Table 1 and control samples treated as described above. The average results and standard deviations (n = 9) are given at the base of Table 1. The skin benefit agent levels quoted refer to the percentage of the sample surface on which the skin benefit agent was found to be present. Table 1 The healthy, i.e. unstressed, control samples showed 22.2% HA staining in the epidermis. Treatment with P1 increased this to 31.2%, an increase of 40%, significant at the 95% level.

[0084] The SDS-stressed controlled showed a reduced HA staining of 9.8% in the epidermis. Treatment with P1 increased this to 13.0%, an increase of 32%, which was not significant at the 95% level.

[0085] The healthy, i.e. unstressed, control samples showed 45.8% HA staining in the papillary dermis. Treatment with P1 increased this to 54.1%, an increase of 18%, significant at the 95% level.

[0086] The SDS-stressed controlled showed a reduced HA staining of 18.6% in the papillary dermis. Treatment with P1 increased this to 35.3%, an increase of 90%, which was significant at the 99% level.

[0087] The healthy, i.e. unstressed, control samples showed 29.8% ceramide staining in the stratum corneum. Treatment with P1 increased this to 38.2%, an increase of 28%, significant at the 99% level.

[0088] The SDS-stressed control samples showed a reduced ceramide staining of 15.2% in the stratum corneum. Treatment with P1 increased this to 30.9%, an increase of 103%, significant at the 99% level.

[0089] The healthy, i.e. unstressed, control samples showed 34.4% Caspase 14 staining in the stratum corneum and the granular layer. Treatment with P1 increased this to 44.5%, an increase of 30%, significant at the 99% level.

[0090] In summary, the water-in-oil stick composition P1 led to:

[0091] • Increased HA levels in both unstressed and stressed skin (epidermis and papillary dermis);

[0092] • Increased ceramide levels in both unstressed and stressed skin (stratum corneum); • Increased Caspase 14 levels in unstressed skin (stratum corneum and granular layer).

[0093] Clearly, water-in-oil stick compositions offer significantly increased levels of key skin benefit agents.

Claims

Claims1. The non-therapeutic use of a water-in-oil emulsion stick composition comprising a humectant for boosting the natural level of ceramides in the human skin.

2. The non-therapeutic use of a water-in-oil emulsion stick according to claim 1 , wherein the composition excludes ceramides.

3. The non-therapeutic use of a water-in-oil emulsion stick according to claim 1 or claim 2 for boosting the natural level of hyaluronic acid in the human skin.

4. The non-therapeutic use of a water-in-oil emulsion stick according to claim 3, wherein the composition excludes hyaluronic acid.

5. The non-therapeutic use of a water-in-oil emulsion stick according to any one of the preceding claims for additionally boosting the natural level of caspases in the human skin.

6. The non-therapeutic use of a water-in-oil emulsion stick according to any one of the preceding claims, wherein the composition excludes caspases.

7. The non-therapeutic use of a water-in-oil emulsion stick according to any of the preceding claims, for aiding the recovery of natural ceramide and / or hyaluronic levels in damaged or stressed human skin.

8. The non-therapeutic use of a water-in-oil emulsion stick composition according to any one of the preceding claims, wherein the composition comprises an antiperspirant active.

9. The non-therapeutic use of a water-in-oil emulsion stick composition according to claim 6, wherein the antiperspirant active is an astringent aluminium salt or aluminium-zirconium salt.

10. The non-therapeutic use of a water-in-oil emulsion stick composition according to claim 7, wherein the antiperspirant active is aluminium sesquichlorohydrate activated by an amino acid and a water-soluble calcium salt.

11. The non-therapeutic use of a water-in-oil emulsion stick composition according to any one of the preceding claims, wherein the composition comprises an ether oil and / or an ester oil.

12. The non-therapeutic use of a water-in-oil emulsion stick composition according to any one of the preceding claims, wherein the composition comprises glycerol.

13. The non-therapeutic use of a water-in-oil emulsion stick composition according to claim 10, wherein the glycerol is present at from 5 to 22% by weight.

14. The non-therapeutic use of a water-in-oil emulsion stick composition according to any one of the preceding claims, wherein the composition is structured with a hydrocarbon wax.

15. The non-therapeutic use of a water-in-oil emulsion stick according to claim 14, wherein the hydrocarbon wax is a polyethylene wax.

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