Skin care benefit cosmetic compositions

Abstract

A cosmetic composition comprising water, dipropylene glycol, a structuring agent and lactic acid or salt thereof.

Description

[0001] Skin Care Benefit Cosmetic Compositions

[0002] Field of Invention

[0003] The invention is concerned with cosmetic compositions capable of boosting the level of a selected natural skin care agent within the skin, via topical application; the selected natural skin care agent being hyaluronic acid (HA).

[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 hyaluronic acid (HA), a natural component of the human body having very high water retention properties.

[0006] HA may be formulated into a wide range of cosmetic skin care compositions and has been claimed to give numerous skin care benefits.

[0007] EP 2,347,755 B1 (Evonik, 2018) discloses cosmetic compositions comprising HA and other active ingredients for reducing skin wrinkles and / or the reduction of the depth of skin pores.

[0008] WO 2023 / 018959 (Roc Opco LLC, 2023) discloses anhydrous cosmetic compositions comprising HA for use in improving skin qualities, in particular hydration.

[0009] The present invention is concerned not with the delivery of HA to the skin, but rather the boosting of the level of HA naturally present within the skin by the topically application of particular cosmetic compositions comprising water, specified glycols, a structuring agent and lactic acid or salt thereof.

[0010] WO 2017 / 182358 (Unilever, 2017) discloses deodorant stick compositions comprising water, propylene glycol (PG), dipropylene glycol (DPG), structurant and glycerol. US 2011 / 300091 discloses a stick that includes as a solvent a glycol or a mixture of glycols. The preferred stick uses a ratio of DPG to PG at a ratio close to 1 :1. 2.

[0011] US 2010 / 0158841 discloses a clear stick that includes DPG and PG at a ratio of 1.78:1.

[0012] US 5,863,524 discloses a stick comprising a polyhydric alcohol. A preferred polyhydric alcohol mixture is predominantly PG with a minor amount of dipropylene 2 5 glycol.

[0013] Summary of Invention

[0014] It is an object of the invention to provide a cosmetic composition comprising water, specified glycols, a structuring agent and lactic acid or salt thereof. It is a particular object of the invention to provide such compositions that are solid sticks suitable for topical application to the skin of the human body.

[0015] In preferred embodiments, the cosmetic composition according to the invention is suitable for all over body topical application, including both underarm areas and more intimate areas.

[0016] It is an object of the invention to provide a cosmetic composition that can boost the natural level of HA within the skin by topical application.

[0017] In certain embodiments of the invention, it is an object to provide deodorancy benefits to the human body and also boost the natural level of HA within the skin.

[0018] In certain embodiments of the invention, it is an object to provide antiperspirancy benefits to the human body and also boost the natural level of HA within the skin.

[0019] In a first aspect of the invention, there is provided a cosmetic composition comprising water, dipropylene glycol (DPG), propylene glycol (PG), a structuring agent and lactic acid or salt thereof, wherein the weight ratio of DPG to PG is greater than 5:1. In a second aspect of the invention, there is provided a method of boosting hyaluronic acid levels within the skin, said method comprising the topical application of a cosmetic composition according to the first aspect of the invention. In preferred embodiments, this method also produces deodorancy and / or antiperspirancy benefits.

[0020] In a third aspect of the invention, there is provided the use of a cosmetic composition according to the first aspect of the invention for boosting hyaluronic acid levels in the human skin.

[0021] In a fourth aspect of the invention, there is provided the use of a cosmetic composition according to the third aspect of the invention for additionally delivering a deodorancy benefit to the surface of the human body.

[0022] Detailed Description

[0023] 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.

[0024] 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”).

[0025] Herein, “ambient conditions” refer to 20°C and 1 atmosphere pressure, unless otherwise indicated.

[0026] Herein, “water insoluble” refers to materials having a solubility in water of less than 0.1 g / 100g, under ambient conditions.

[0027] Herein, all percentages, ratios and amounts are by weight, unless otherwise indicated. Herein, amounts and concentrations of ingredients are percentages by weight of the total composition, unless otherwise indicated.

[0028] Herein, references to amounts of components such as “structuring agent” or “glycol” relate to the total amount of such components present in the composition.

[0029] Herein, the word “comprising” is intended to mean “including” but not necessarily “consisting of”, i.e. , it is non-exhaustive.

[0030] Herein, all uses, methods and compositions should be understood to be cosmetic uses, methods and compositions; that is to say, non-therapeutic uses, methods and compositions.

[0031] Herein, references to the dermis refer in particular to the papillary dermis, the top level of the dermis located immediately below the epidermis.

[0032] The total amount of lactic acid and salts thereof is preferably at least 0.1 , more preferably at least 0.5% and most preferably at least 1 %. At the upper levels of incorporation, the lactic acid and salts thereof is preferably 20% or less, more preferably 12% or less and most preferably 6% or less. Preferred ranges may be formed from any of the lower and upper incorporation preferences indicated in this paragraph; e.g., from 0.5 to 20%.

[0033] Surprisingly, the promotion or boosting of HA levels within the skin can be done by topical application of a composition according to the invention that does not itself comprise HA. Indeed, it is preferred that compositions of the invention exclude, i.e. are free from, HA.

[0034] The structuring agent used in compositions of the invention typically serves to solidify the composition, producing a solid cosmetic stick composition.

[0035] Herein, “solid” and “solidified” refer to a state of matter incapable of flow at a temperature of 25°C and a pressure of 1 atmosphere. The structuring agent may be a single structural or a mixture of structurants. Preferably, the structurant is present at from 0.5 to 15%, more preferably 1 to 10 wt.% and most preferably from 2 to 8%.

[0036] The structuring agent is preferably a C12 to C24 fatty acid or salt thereof. More preferably the structuring agent is a C16 to C18 fatty acid and most preferably it is sodium stearate.

[0037] In compositions according to the invention, the ratio of DPG to PG is greater than 5:1. Preferably it is from 5.5:1 to 10:1 , more preferably from 6:1 to 10:1 , and most preferably from 7:1 to 10:1.

[0038] The total level of DPG and PG is preferably from 30 to 70%, more preferably from 35 to 60% and most preferably from 40 to 50%. DPG is preferably present at from 25 to 55%, more preferably from 30 to 50% and most preferably from 35 to 45%. PG is preferably present at from 3 to 10%, more preferably from 4 to 8% and most preferably from 4.5 to 6.5%. Each of the preference levels for DPG may be combined with each of the preference levels for PG. These amounts and ratios help with the sensory properties of the product and the deodorancy benefit that it delivers.

[0039] Water is an essential component of compositions of the invention. The content of water is preferably from 18 to 40%, more preferably from 20 to 36% and most preferably from 22 to 36%, these amounts helping to reduce or eliminate insoluble matter in the stick.

[0040] The ratio of water to glycols is preferably from 20: 80 to 50: 50 and more preferably from 25: 75 to 45: 55, these ratios helping to reduce or eliminate insoluble matter in the stick.

[0041] A preferred additional component in compositions used in the invention is a humectant 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. When employed, 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. In compositions of the invention, glycerol is an especially preferred additional component. In such compositions, the ratio of dipropylene glycol to glycerol is preferably from 1:1 to 3:1 , more preferably from 1.5:1 to 2.75:1, and most preferably from 2:1 to 2.5:1. The amount of glycerol is preferably from 1 to 25%, more preferably from 5 to 22% and most preferably from 10 to 20%. These preferred ratios aid with the sensory properties of the product.

[0042] The cosmetic composition is suitable for topical application. In preferred embodiments, the water-in-oil emulsion stick composition is suitable for all over body topical application, including both underarm areas and more intimate areas. Preferred compositions, in particular those suitable for all over body use, do not comprise any aluminium-containing antiperspirant active.

[0043] Compositions according to the invention are preferably homogeneous and / or single phase compositions.

[0044] In preferred embodiments the cosmetic composition is used for boosting hyaluronic acid levels in the human skin and delivering a deodorancy benefit.

[0045] Surprisingly, we have found that boosting hyaluronic acid levels and deodorising human skin may be achieved by compositions of the invention without the use of an additional deodorant active.

[0046] A preferred additional component in compositions used in the invention, and particularly in emulsion compositions, 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.

[0047] 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.

[0048] 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%.

[0049] 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.

[0050] 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.

[0051] 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.

[0052] 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.

[0053] 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™.

[0054] Other components that may be included in composition used in the invention include those described in the following paragraphs.

[0055] 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).

[0056] 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%.

[0057] 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%.

[0058] Examples

[0059] The following Examples are illustrative of the invention and non-limiting as to its scope.

[0060] The deodorant stick compositions indicated in Table 1 were prepared by methods known in the art. They differed only in the presence of potassium lactate in one and its replacement by water in the other. The Examples had good solidity and stability. The Examples / products were tested in the following 3-day study. The results are indicated at the base of Table 1.

[0061] 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.

[0062] On day 1 of the study, 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 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. Products were applied topically at 2 mg per 1 cm2explant and spread using a spatula. 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.

[0063] 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. 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).

[0064] Samples from the epidermal layer and papillary dermis layer of the skin were analysed and a comparison made between those treated with the Examples 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 HA levels quoted refer to the percentage of the sample surface on which HA was found to be present. Table 1

[0065] Treatment with the 1.25% SLS solution reduced the hyaluronic acid level of the epidermis by 43% by day 3 of the study: from 22.1% coverage to 12.5% coverage. When the explants were post-treated with P4, the HA level was increased by 64% compared with the SLS treatment alone. When the explants were post-treated with P1 , the HA level was increased by 48% compared with the SLS treatment alone. Both of these results were significant at the 99%; however, the difference between the two treatments was only directional.

[0066] Treatment with the 1.25% SLS solution reduced the hyaluronic acid level of the dermis by 24% by day 3 of the study: from 47.8% coverage to 36.2% coverage. When the explants were post-treated with P4, the HA level was not significantly effected compared with the SLS treatment alone. When the explants were post-treated with P1 , the HA level was increased by 26% compared with the SLS treatment alone, this difference being significant at the 95% level. This result shows how an aqueous polyol mixture comprising potassium lactate can increase HA levels in the skin.

Claims

Claims1. A cosmetic composition comprising water, dipropylene glycol (DPG), propylene glycol (PG), a structuring agent and lactic acid or salt thereof, wherein the weight ratio of DPG to PG is greater than 5:1.

2. A cosmetic composition according to any one of the preceding claims, wherein the structuring agent is a fatty acid soap.

3. A cosmetic composition according to claim 2, wherein the fatty acid soap is sodium stearate.

4. A cosmetic composition according to any one of the preceding claims, comprising a humectant selected from glycerol and / or a PEG oligomer of weight average molecular weight of from 180 to 420.

5. A cosmetic composition according to claim 5, comprising glycerol at from 5 to 22% by weight.

6. A cosmetic composition according to any one of the preceding claims, comprising an additional deodorant active.

7. A cosmetic composition according to any one of the preceding claims which is suitable for all over body use.

8. A cosmetic composition according to claim 7 or claim 8, comprising a nonaluminium antiperspirant active.

9. A method of boosting hyaluronic acid levels within the skin, said method comprising the topical application of a cosmetic composition according to any one of the preceding claims.

10. The use of a cosmetic composition according to any one of the preceding claims for boosting hyaluronic acid levels in the human skin.

11. The use of a cosmetic composition according to claim 11 , wherein a deodorancy benefit is also delivered to the skin of the human body.

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