Skin whitening composition

Abstract

The present invention relates to a personal care composition that lightens the skin. In particular, the present invention relates to a topical composition that is effective against hyperpigmentation. This is achieved by including hydroxystearic acid (HSA) and tetrahydroxypropylethylenediamine (THPE) in the topical composition. The efficacy is further enhanced by including niacinamide.

Description

[Technical field]

[0001] The present invention relates to personal care compositions, in particular topical compositions that are effective in reducing melanin synthesis to lighten the skin. [Background technology]

[0002] Most people consider the appearance of their skin, especially on the face, as one of the important indicators of their own beauty and health. Thus, having a light, blemish-free, even skin tone is desired by many. The degree and evenness of skin pigmentation is affected by factors such as age, hormonal changes, acne outbreaks, and exposure to sunlight and air pollution. These can cause hyperpigmentation of certain localized areas of the skin, such as age spots, freckles, or dark circles under the eyes. Many believe that certain lifestyle factors, such as hydration (amount of water consumed), type of food, and amount and quality of sleep, also affect the appearance of the skin. People know that even if they make changes such as living a healthier lifestyle, it will take a long time to even out the appearance of their skin, so they turn to cosmetic solutions that temporarily solve the blemishes on their skin. They also want such products to reduce the darkening of the skin caused by exposure to sunlight. To meet this need, many attempts have been made to develop products that reduce pigment production in melanocytes.

[0003] The inventors have been working in this field for many years, have filed several patent applications, and have manufactured and marketed various cosmetic products. In this invention, the inventors were specifically looking for a cost-effective solution to this problem that could be achieved using commonly used cosmetic ingredients to impart an even and bright skin tone.

[0004] The present inventors have recognized that certain hydroxystearic acids (HSA), such as 12-hydroxystearic acid, provide a skin whitening effect, and for example, WO09153169 discloses skin whitening additives and compositions comprising at least one hetero-substituted saturated or unsaturated fatty acid. The compositions disclosed therein have been found to be suitable for topical application and may include 12-hydroxystearic acid, ricinoleic acid, or both. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] WO09153169 Summary of the Invention [Problem to be solved by the invention]

[0006] During the course of extensive experimentation in this field, the inventors were searching for certain commonly available and inexpensive active substances that would interact with HSA to enhance the effect of reducing melanin in the skin, and even provide a synergistic effect. The inventors came across tetrahydroxypropylethylenediamine (THPE), a commonly used chelating agent, and found that combining it with HSA enhanced efficacy. THPE has been reported to be a skin darkening substance, and for example, US2011 / 0081305 discloses a composition comprising skin lightening resorcinol and a skin darkening substance. The composition disclosed therein can be applied topically to the skin to treat signs of aging.

[0007] It is therefore an object of the present invention to provide a solution to hyperpigmentation, uneven skin appearance and sun-induced darkening, thereby resulting in a brighter and more even skin appearance.

[0008] It is yet another object of the present invention to provide a cost-effective solution. [Means for solving the problem]

[0009] The first aspect of the present invention is (i) 0.1 to 4.0% tetrahydroxypropylethylenediamine; (ii) hydroxystearic acid, preferably 12-hydroxystearic acid; and (iii) Cosmetically acceptable carriers The present invention relates to a skin whitening composition comprising:

[0010] Another aspect of the invention relates to a method for lightening the skin, comprising applying to the skin a composition according to any one of the claims. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] These and other aspects, features and advantages will become apparent to those skilled in the art upon reading the following detailed description and the appended claims. For the avoidance of doubt, any feature of one aspect of the present invention may be utilized in any other aspect of the present invention. The expression "comprising" is intended to mean "including" but not necessarily "consisting" or "composed of". In other words, the steps or options described need not be all-inclusive. It should be noted that the examples described below are intended to clarify the invention and are not intended to limit the invention to those examples themselves. Similarly, unless otherwise indicated, all percentages are weight / weight percents. Except in the examples and comparative examples, or unless expressly indicated, all numbers in this Detailed Description and Claims describing amounts of materials or reaction conditions, physical properties and / or uses of materials should be understood as being modified by the word "about". Numerical ranges expressed in the format "from x to y" are understood to include x and y. It is understood that when multiple preferred ranges for a particular feature are described in the format "from x to y," all ranges combining the different endpoints are also contemplated.

[0012] The topical compositions of the present invention are intended for use in personal care or cosmetic applications and may also be referred to as personal care or cosmetic compositions. "Personal care compositions" as used herein is meant to include compositions for topical application, i.e., application to the external surface of human skin and / or hair. Such compositions may be classified as leave-on or wash-off, and include products that are applied to the human body for appearance improvement, cleansing, odor control, or general beauty. The compositions are preferably leave-on. The compositions of the present invention in the leave-on form may be in the form of a gel, emulsion, lotion, or cream. A preferred composition is a cream. It is believed that the compositions may be wash-off, i.e., compositions used to cleanse the skin. Such compositions generally contain a large amount of surfactants. They are usually diluted in a large amount of water and applied to the skin or hair, with a large amount of foam. The composition is then rinsed off with a large amount of water, during which the oils and dirt removed from the cleaning agent micellize in the rinse water, leaving the skin surface cleaner than before the cleaning operation.

[0013] "Skin" as used herein includes the skin of the face and body (eg, neck, chest, back, arms, armpits, hands, feet and scalp), particularly exposed areas thereof.

[0014] The compositions of the present invention include tetrahydroxypropylethylenediamine (THPE) having the formula:

[0015] [ka]

[0016] THPE is contained in an amount of 0.1 to 4.0% by weight, preferably 0.5 to 2% by weight, of the composition.

[0017] The composition of the present invention comprises hydroxystearic acid. The hydroxystearic acid is preferably 10-hydroxystearic acid, 12-hydroxystearic acid or trihydroxystearic acid (e.g., 9,10,13-trihydroxystearic acid) or trihydroxystearin, or a compound which upon decomposition produces one or more molecules of hydroxystearic acid or hydroxystearic acid compounds, such as a mono-, di- or triester of glycerol and hydroxystearic acid. Of these, 10-hydroxystearic acid, 12-hydroxystearic acid and 9,10,13-trihydroxystearic acid are more preferred, and 12-hydroxystearic acid (12-HSA) is the most preferred. 12-HSA has the following structure:

[0018] [ka]

[0019] Hydroxystearic acid is comprised in an amount of 0.1 to 5% by weight of the composition, more preferably 0.2 to 4% by weight, even more preferably 0.5 to 2% by weight.

[0020] The compositions preferably include niacinamide, also known as nicotinamide and pyridine-3-carboxamide, which is the active water-soluble form of vitamin B3. When included, the compositions of the present invention will contain an effective amount of niacinamide, typically at a concentration of 0.1-3%, more preferably 0.5-2% by weight of the composition.

[0021] The composition may include an organic sunscreen selected from one or both of UVA and UVB sunscreens. Sunscreens include materials commonly used to block ultraviolet radiation. Exemplary compounds are derivatives of PABA, cinnamic acid, and salicylic acid. For example, avobenzophenone (Parsol 1789®), octyl methoxycinnamate, and 2-hydroxy-4-methoxybenzophenone (also known as oxybenzone) can be used. Octyl methoxycinnamate and 2-hydroxy-4-methoxybenzophenone are commercially available under the trade names Parsol MCX and Benzophenone-3, respectively. The exact amount of sunscreen used in the composition can vary depending on the degree of protection desired from the sun's ultraviolet radiation. Additives that reflect or scatter the sun's rays can also be used. These additives include oxides such as zinc oxide and titanium dioxide.

[0022] The compositions of the present invention may further comprise a cosmetically acceptable carrier which may act as a diluent, dispersant and / or carrier for the active substances used in the composition to facilitate their distribution when the composition is applied to the skin. Cosmetically acceptable vehicles suitable for use in the present invention may be aqueous, non-aqueous or emulsions; aqueous or emulsions, with water-in-oil or oil-in-water emulsions being most preferred. When water is present, it typically constitutes the remainder of the composition. Preferably, water is present in a concentration of 5-99% by weight of the composition, more preferably 20-80% by weight, even more preferably 40-80% by weight.

[0023] Leave-on Compositions The leave-on composition of the invention can be provided in the form of a cream, lotion or gel, preferably in the form of a cream. A preferred form of the solid composition is a cream, even more preferably having a vanishing cream base. The vanishing cream base comprises 3-25% by weight of a fatty acid. Optionally, the composition may comprise 0.1-10% by weight of a soap. If present, the fatty acid is preferably a C10-C22 fatty acid, more preferably a C16-C18 fatty acid. Most preferably, the fatty acid is stearic acid or palmitic acid or a mixture thereof, and the soap is preferably a potassium salt of a fatty acid mixture. The fatty acid is often substantially (generally about 90-95%) hystric acid, which is a mixture of 45% stearic acid and 55% palmitic acid. The most preferred cream is a cream comprising 3-25% by weight of a fatty acid and 0.1-10% by weight of a soap.

[0024] Preferably, the composition comprises an emollient. Examples of emollients that may be used in the leave-on composition include stearyl alcohol, glyceryl monoricinoleate, mink oil, isopropyl isostearate, isobutyl palmitate, isocetyl stearate, oleyl alcohol, isopropyl laurate, hexyl laurate, decyl oleate, octadecane-2-ol, isocetyl alcohol, eicosanyl alcohol, behenyl alcohol, cetyl palmitate, silicone oils such as dimethylpolysiloxane, di-n-butyl sebacate, isopropyl myristate, palmitic acid, glyceryl stearate ... Examples of suitable oils include isopropyl acetate, isopropyl stearate, butyl stearate, polyethylene glycol, triethylene glycol, lanolin, cocoa butter, corn oil, cottonseed oil, olive oil, palm kernel oil, rapeseed oil, safflower seed oil, evening primrose oil, soybean oil, sunflower seed oil, avocado oil, sesame seed oil, coconut oil, peanut oil, castor oil, acetylated lanolin alcohol, petrolatum, mineral oil, butyl myristate, isopropyl linoleate, lauryl lactate, myristyl lactate, decyl oleate, myristyl myristate, and mixtures thereof.

[0025] Preferably, the composition includes a solvent. Examples of solvents that can be used in the composition include ethyl alcohol, isopropanol, acetone, ethylene glycol monoethyl ether, diethylene glycol monobutyl ether, diethylene glycol monoethyl ether, and mixtures thereof. The composition can include a polyhydric alcohol selected from one or more of glycerin, 1,3-butylene glycol, propylene glycol, 1,3-propanediol, pentylene glycol, hexylene glycol, and sorbitol.

[0026] Preferably, the composition comprises a powder. Examples of powders that can be used in the composition include chalk, talc, fuller's earth, kaolin, starch, gums, colloidal silica, sodium polyacrylate, tetraalkyl and / or trialkylaryl ammonium smectites, chemically modified magnesium aluminum silicate, organically modified montmorillonite clay, hydrated aluminum silicate, fumed silica, carboxyvinyl polymers, sodium carboxymethylcellulose, ethylene glycol monostearate, and mixtures thereof.

[0027] Preferably, the composition includes a preservative to prevent the growth of potentially harmful microorganisms. Examples of ingredients that can be used as preservatives in the composition include alkyl esters of para-hydroxybenzoic acid, hydantoin derivatives, propionate salts, and various quaternary ammonium compounds. More preferably, ingredients that can be used as preservatives in the composition include sodium benzoate, iodopropynyl butylcarbamate, methylisothiazolinone, iodopropynyl butylcarbamate, phenoxyethanol, methylparaben, propylparaben, imidazolidinyl urea, sodium dehydroacetate, ethylhexylglycerin, benzyl alcohol, alkanediols, and mixtures thereof. When present in the composition, the preservative is preferably added in an amount of 0.001-5% by weight, more preferably 0.01-3% by weight, most preferably 0.02-2% by weight, and even most preferably 0.25-1.5% by weight.

[0028] Preferably, the composition contains a wide range of other optional ingredients including antioxidants, binders, buffers, colorants, astringents, fragrances, opacifiers, conditioners, exfoliants, pH adjusting agents, skin feel agents, skin emollients, and skin healing agents.

[0029] The packaging of the compositions of the present invention can be a patch, bottle, tube, roll-ball applicator, propellant-driven aerosol device, squeeze container, or jar with a lid.

[0030] Wash-off Composition When provided for wash-off purposes, the compositions of the present invention may take the form of a liquid, lotion, cream, foam, scrub, gel, shampoo, conditioner, hand wash, facial cleanser, or body wash product.

[0031] The cosmetically acceptable carrier in this case generally comprises water in addition to the surfactant. Particularly preferred surfactants are anionic surfactants such as soaps. The soaps for preparing the cleansing compositions of the present invention are preferably C8-C 24 Soap, preferably C 10 -C 20 Soap, most preferably C 12 -C 18 It is a soap. The cation of the soap can be an alkali metal, an alkaline earth metal, or ammonium. Preferably, the cation of the soap is selected from sodium, potassium, or ammonium. More preferably, the cation of the soap is sodium or potassium. Fatty acids derived from other suitable oils / fats such as peanut, soybean, tallow, palm, palm kernel, etc., can also be used in other desired proportions. The cosmetically acceptable carrier in this form generally forms 80-99% by weight of the cleansing composition.

[0032] When present, the anionic surfactant, e.g., soap, is preferably present in an amount of 1-90% by weight of the cleansing composition, preferably 10-85% by weight, more preferably 25-75% by weight. The cleansing composition is preferably in solid or semi-solid form, most preferably in solid form. A preferred solid composition is in the form of a bar of soap.

[0033] The other anionic surfactants are preferably selected from alkyl ether sulfates, primary alkyl sulfates, secondary alkyl sulfonates, alkyl benzene sulfonates, or ethoxylated alkyl sulfates. Preferred non-soap anionic surfactants in the cleansing composition are alkyl ether sulfates, preferably those having 1 to 3 ethylene oxide groups from natural or synthetic sources and / or sulfonic acids. Particularly preferred is sodium lauryl ether sulfate. Alkyl polyglucosides may also be present in the composition, preferably C6-C 16 The carbon chain length is

[0034] Preferred cleansing compositions may contain other known ingredients such as fragrances, pigments, preservatives, emollients, sunscreens, gelling agents and thickeners. The selection of these ingredients depends mostly on the format of the composition. Water is the preferred carrier. When water is present, it is preferably present at least 1% by weight of the composition, more preferably at least 2% by weight, and even more preferably at least 5% by weight. When water is the carrier, preferred cleansing compositions contain 10-50% by weight, more preferably 12-40% by weight, and even more preferably 12-25% by weight of water.

[0035] The cleansing compositions of the present invention may also be delivered via moisturizing bars or moisturizing liquid compositions. Moisturizing bar compositions comprising fatty acyl isethionates (e.g., cocyl isethionate) are particularly preferred.

[0036] Fatty acyl isethionate (e.g., cocoyl isethionate) surfactant "products" are defined as mixtures of anionic acyl isethionate surfactants and fatty acids / fatty acid soaps. They are highly desirable in personal care, particularly skin or hair cleansing products, due to their high lathering, skin-friendly, and good emollient properties. Typically, fatty acid isethionate surfactant products are prepared by esterification of fatty acids or by the addition of C8-C 20 The fatty acyl isethionate is prepared by reacting a fatty acid chloride having a carbon chain length of 100 to 200 nm with an isethionate salt. A typical surfactant product containing fatty acyl isethionate salt contains, in addition to the isethionate salt, about 40-95% by weight of the acid isethionate salt, and 5-50% by weight, typically 10-40% by weight, of free fatty acid, in addition to the isethionate salt, typically less than 5% and trace amounts (less than 2% by weight) of other additives. Such compositions may also contain alkyl taurates, such as alkyl taurate amides. Such alkyl taurate amides may be prepared by reacting taurine, methyl taurine, or the corresponding taurate salts (e.g., NH2CH2CH2SO3M + , where M + The alkyl taurate amides can be prepared by reaction with sodium or potassium counterions and appropriate fatty acids. Preferred alkyl taurate amides include sodium methyl cocoyl taurate and sodium methyl lauroyl taurate. Fatty acid soaps may be included in the range of 5-15% by weight. Other surfactants such as betaine may be included in the range of 1-5% by weight. Water is typically included in the range of 2-8% by weight of the composition.

[0037] Additionally, the wash-off compositions of the present invention may contain polyhydric alcohols. The polyhydric alcohols described above as useful in the leave-on forms can also be used in the wash-off forms.

[0038] In a second aspect, the present invention relates to the use of a composition according to the invention for skin whitening.

[0039] In a third aspect, the present invention relates to a method for lightening human skin, comprising the step of applying to the skin a composition according to the present invention.

[0040] The invention is illustrated by the following non-limiting examples. EXAMPLES

[0041] Example AB, 1: Melanin Inhibition by Skin Cleansing Compositions The effects of a combination of active ingredients such as 58% 12HSA (Example B) and 1.58% 12HSA + 2% THPE (Example-1) were compared to a control formulation (Example-A) that did not contain either of the two active ingredients. The base formulation (Example-A) is shown in Table-1 below.

[0042] Table-1 [Table 1]

[0043] Formulations A, B, and 1 were tested for % inhibition of melanin using the protocol provided below. 3D Model Cleansing Protocol: Day 0: Episkin RHPE (skin type: VI) tissue was removed from the transport plate and placed into a new 24-well plate containing 450 μL of maintenance medium (provided by Episkin).

[0044] Day 1: After 18 hours ± 2 hours of incubation in a 37°C, 5% CO2 incubator, the tissues were removed from the plates and the spent medium was stored at -80°C. The tissues were transferred to a new 24-well plate containing 450 μL of growth medium (provided by Episkin). A nylon mesh (provided by Episkin) was prepared for application of the activator by diluting the formulation 1:1 with distilled water and adding approximately 2 mg of the formulation onto the mesh using a 1 mL syringe and applying evenly to ensure even coverage of the mesh. The coated mesh was placed on top of the tissue for 20 seconds. After 20 seconds, the mesh was removed and the tissue was washed twice with distilled water for 20 seconds and incubation continued for 48 hours in a 37°C, 5% CO2 incubator. Day 3: Tissues were transferred to a new 24-well plate containing 450 μL of fresh growth medium. Then, application of the formulations outlined on day 1 was repeated. Day 5: The steps from day 3 were repeated. Day 7: The tissues were washed with distilled water and melanin content estimation and MTT assay were performed.

[0045] Melanin content estimation : The tissue was transferred to a 1.5 mL Eppendorf tube containing 150 μL of Solvable (Tissue and Gel Solubilizer 0.5M - Packard Bioscience Co. Cat. No. 6NE9100). The tube was then incubated at 60°C for 12-16 hours with gentle shaking. After complete dissolution, the tube was left at room temperature for 30 minutes. The tube was then centrifuged at 1000 rpm for 10 minutes. 100 μL of the supernatant was then transferred to a 384-well plate and a spectrophotometer OD reading at 490 nm was taken to measure the melanin content in the samples.

[0046] The results in terms of % melanin inhibition are summarized in Table 2 below.

[0047] Table 2: Melanin Inhibition Rate [Table 2]

[0048] The data in the table above shows that the inclusion of 1.58% 12HSA and 2% THPE significantly improved melanin suppression compared to the control sample.

[0049] Example CF,2:12 Effect of combination of HSA, THPE, and niacinamide on melanin synthesis in melanocyte cells in vitro Using the active substances shown in Table 3, experiments on melanocyte cells were carried out according to the following procedure. 1. Plate human primary melanocytes at 5 × 10 per well in a 24-well plate with fresh Melanocyte Growth Medium (MGM). 4 The seeds were sown at a density of 1000 x 1000 mm. 2. 24 hours after seeding, cells were treated with active agents in fresh MGM medium and incubated in a 5% CO2 / 37°C incubator for 72 hours. After 3.72 hours of incubation, melanin estimation was performed.

[0050] Melanin content estimation: Cell culture spent medium was removed and cells were washed once with 200 μL of 1× PBS. After washing, 120 μL / well of MCA (Melanin Content Assay) reagent (10% DMSO in 1N NaOH) was added and incubated at 60°C for 1 h in a shaker incubator. Then, 100 μL of this lysate was transferred to a new 384-well plate and the absorbance was measured spectrophotometrically at 405 nm using a microplate reader.

[0051] Table-3 [Table 3]

[0052] The data in Table 3 above shows that the inclusion of niacinamide in addition to THPE and hydroxystearic acid further enhances melanin inhibition, resulting in more even pigmentation and an overall lighter skin tone.

Claims

1. (i) 0.1-4.0% tetrahydroxypropylethylenediamine; (ii) hydroxystearic acid, preferably 12-hydroxystearic acid; and (iii) A cosmetically acceptable carrier.

1. A skin whitening composition comprising:

2. The composition of claim 1 comprising 0.1 to 5% hydroxystearic acid.

3. The composition of claim 1 or 2, further comprising niacinamide.

4. The composition of claim 3 comprising 0.1 to 3% niacinamide.

5. A leave-on composition according to any one of the preceding claims, wherein the cosmetically acceptable carrier is in the form of a gel, emulsion, lotion or cream.

6. The composition according to claim 5 in the form of a cream.

7. The composition of claim 6, wherein the cream comprises 3-25% by weight of fatty acids and 0.1-10% by weight of soap.

8. A wash-off type composition according to any one of claims 1 to 4, wherein the cosmetically acceptable carrier comprises water and a surfactant.

9. 2. A composition according to any one of the preceding claims, wherein the cosmetically acceptable carrier comprises a polyhydric alcohol.

10. 10. The composition of claim 9, wherein the polyhydric alcohol is selected from one or more of glycerin, 1,3-butylene glycol, propylene glycol, 1,3-propanediol, pentylene glycol, hexylene glycol, and sorbitol.

11. 2. The composition of any one of the preceding claims, further comprising an organic sunscreen selected from one or both of a UVA sunscreen and a UVB sunscreen.

12. A method for providing shine to skin comprising the step of applying to the skin a composition according to any one of the preceding claims.

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