Stable Skin Care Emulsion and Method of Using the Same

Abstract

Sucrose esters, such as sucrose laurate and sucrose dilaurate, are known to be extremely difficult to emulsify in oil-in-water emulsions and tend to destabilize these types of emulsions. It has now been discovered that by combining sucrose esters with certain hydrophobically modified aqueous rheology modifiers and nonionic stearic acid derivative emulsifiers, emulsion stability can be significantly improved.

Description

Technical Field

[0001] The present disclosure generally relates to improving the stability of emulsions containing destabilizing components. More specifically, the present disclosure is directed to improving the stability of skin care composition emulsions containing emulsion-destabilizing sucrose esters.

Background Art

[0002] The skin is the first line of defense against environmental damage that can potentially harm sensitive underlying tissues and organs. For example, the skin maintains a relatively water-impermeable barrier between the living organism and its environment to prevent dehydration. Additionally, the skin plays an important role in a person's physical appearance. Generally, most people desire skin that looks younger and healthier. For some of these people, visible signs of skin aging such as thin skin, wrinkles, and age spots are undesirable reminders of the loss of youth. As a result, treating the signs of skin aging has become a rapidly growing industry in a youth-conscious society. Treatments range from cosmetic creams and moisturizers to various forms of plastic surgery.

[0003] A number of skin care agents, both natural and synthetic, are known for use in skin care compositions for treating a variety of skin conditions, particularly those associated with aging. For example, U.S. Patent No. 9,949,917 and U.S. Patent Application Publication No. 2005 / 0220726 disclose cosmetic compositions containing sucrose fatty acid esters such as sucrose laurate, sucrose dilaurate, and sucrose trilaurate for use as skin whitening agents. However, when the skin care composition is provided in the form of an emulsion, these sucrose fatty acid esters can destabilize the emulsion due to their emulsifying properties (i.e., due to the hydrophilic and lipophilic moieties in these compounds). The instability of the emulsion can manifest in a wide variety of forms (e.g., aggregation, creaming, sedimentation, or coalescence), all of which are generally undesirable in a skin care composition.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] Therefore, it is desirable to provide a skin care composition in the form of an emulsion that contains sucrose fatty acid esters as a skin care agent and has desirable stability.

Means for Solving the Problems

[0006] A skin care composition with improved emulsion stability is disclosed herein, which comprises from about 0.0001% to about 10% by weight of a sucrose ester selected from sucrose laurate, sucrose dilaurate, sucrose trilaurate, and combinations thereof; from about 0.01% to about 5% by weight of a hydrophobically modified aqueous rheology modifier; from about 0.005% to about 5% by weight of a nonionic stearic acid derivative emulsifier; and a dermatologically acceptable carrier in the form of an oil-in-water emulsion. Also disclosed herein are methods for preparing and using the novel compositions.

Brief Description of the Drawings

[0007]

Figure 1

Figure 2

Figure 3

Mode for Carrying Out the Invention

[0008] It is known to use sucrose fatty acid esters in skin care compositions. However, at least some sucrose fatty acid esters, such as sucrose laurate and sucrose dilaurate, can destabilize the oil phase of emulsions, particularly oil-in-water emulsions. Surprisingly, it has now been discovered that by selecting specific emulsifiers and rheology modifiers, the stability of emulsions containing sucrose fatty acid esters can be significantly improved. Specifically, by selecting a hydrophobically modified aqueous rheology modifier and a suitable nonionic medium- to long-chain fatty acid derivative emulsifier (e.g., an emulsifier derived from stearic acid), the emulsion stability can be significantly improved in the presence of sucrose esters.

[0009] References to "embodiments" and the like in this specification mean that the specific materials, features, structures, and / or characteristics described in connection with those embodiments are included in at least one embodiment, optionally in a number of embodiments, but do not mean that the described materials, features, structures, and / or characteristics are incorporated into all embodiments. Further, the materials, features, structures, and / or characteristics may be combined in any suitable manner across different embodiments, and the materials, features, structures, and / or characteristics may be excluded from or substituted for those described. Accordingly, the embodiments and aspects described in this specification may include or be combined with elements or components of other embodiments and / or aspects, even if not explicitly illustrated in combination, unless otherwise noted or incompatibility is mentioned.

[0010] In all embodiments, unless otherwise specifically noted, all percentages of components are based on the weight of the cosmetic composition. Unless otherwise specifically noted, all ratios are by weight. The number of significant digits does not represent a limitation on the quantity being expressed nor a limitation on the accuracy of the measured value. Unless otherwise specifically indicated, all quantities are understood to be modified by the word "about". Unless otherwise indicated, all measurements are understood to be made at approximately 25°C under ambient conditions, where "ambient conditions" means conditions of about 1 atmosphere and a relative humidity of about 50%. All numerical ranges are inclusive and combinable to form sub-ranges not explicitly disclosed. For example, the upper and lower range limits separated are compatible in creating further ranges.

[0011] The composition of the present invention can contain, consist essentially of, or consist of the essential components and optional components described herein. As used herein, "consisting essentially of" means that a composition or component can contain only additional components that do not substantially change the basic and novel characteristics of the claimed composition or method. As used in this specification and the appended claims, the singular forms "a", "an", and "the" are intended to include the plural forms as well, unless the context clearly dictates otherwise.

[0012] Definitions "About" refers to a range equal to plus or minus twenty percent (±20%) or a lower value (e.g., 15%, less than 10%, or even less than 5%) of the recited value, modifying a particular value.

[0013] "Agent" refers to a material intended to provide a particular benefit or function, as well as any of its components. For example, a skin softening agent is a material (e.g., an aliphatic alcohol) intended to provide a skin softening benefit to the skin, and a thickening agent is generally a material aimed at increasing the viscosity of a composition.

[0014] When used in connection with a composition, "applying" or "application" means applying or spreading the composition of this specification onto a body surface such as the skin or hair.

[0015] "Cosmetic composition" means a composition containing cosmetic agents and intended for non-therapeutic (i.e., non-medical) use. Examples of cosmetic compositions include color cosmetics (e.g., foundation, lipstick, concealer, and mascara), skin care compositions (e.g., moisturizers and sunscreens), personal care compositions (e.g., rinse-off and non-rinse-off body soaps and bar soaps), and hair care compositions (e.g., shampoos and conditioners).

[0016] As used herein, "derivative" means an amide, ether, ester, amino, carboxyl, acetyl, and / or alcohol derivative of a given compound.

[0017] "Effective amount" means an amount of a compound and composition sufficient to significantly induce a positive benefit to a keratinous tissue over the course of a treatment period. The positive benefit can be a health, appearance, and / or tactile benefit, including, independently or in combination, the benefits disclosed herein.

[0018] "Emulsion stability" and variations thereof refer to the ability of an emulsion to resist changes in its properties over time. The changes may be physical or chemical, and may be visible or invisible. For example, lack of emulsion stability can manifest as visible phase separation (i.e., creaming or sedimentation). In another example, emulsion instability can manifest as an (invisible to the human eye) coalescence of droplets in the dispersed phase that results in a change in viscosity or flow characteristics. Emulsion stability is characterized herein as an instability index, which can be determined according to a photocentrifugation test described in more detail below.

[0019] "Skin care" means to regulate and / or improve the skin condition (e.g., skin health, appearance, or texture / tactility). Some non-limiting examples of improving the skin condition include improving the appearance and / or tactile sensation of the skin by providing a smoother and more uniform appearance and / or tactile sensation; increasing the thickness of one or more layers of the skin; improving the elasticity or resilience of the skin; improving the firmness of the skin; reducing the greasy, shiny, and / or dull appearance of the skin, improving the moisture content or hydration of the skin, improving the appearance of fine lines and / or wrinkles, improving skin exfoliation or flaking, plumping the skin, improving skin barrier properties, improving the skin color, reducing the appearance of redness or skin blemishes, and / or improving the brightness, gloss, or transparency of the skin.

[0020] "Skin care active substance" means a compound or combination of compounds that, when applied to the skin, provides acute and / or chronic benefits to the skin or to a type of cell commonly found in the skin. A skin care active substance can regulate and / or improve the skin or skin-related cells (e.g., improve skin elasticity, moisture content, skin barrier function, and / or cell metabolism).

[0021] "Skin care composition" means a composition that contains a skin care active substance and regulates and / or improves the skin condition.

[0022] "Treatment period", as used herein, means the length and / or frequency of time that a material or composition is applied to the target skin surface.

[0023] Composition The compositions herein are in the form of emulsions (e.g., oil-in-water emulsions) containing a sucrose ester, a hydrophobically modified aqueous rheology modifier, a nonionic medium- to long-chain fatty acid derivative emulsifier, and a dermatologically acceptable carrier in the form of an oil-in-water emulsion. The combination of the rheology modifier and the sucrose ester is selected to provide an emulsion with improved stability. The stable emulsions herein have an instability index of less than 5% (e.g., less than 4%, less than 3%, less than 2%, less than 1%, or even less than 0.5%). The stable emulsions herein have a relative instability of less than 25% (e.g., less than 20%, less than 15%, or even less than 10%) when normalized against a negative control. Stable emulsions can include very stable emulsions and partially stable emulsions, both of which can be acceptable to consumers. Suitable methods for determining the instability index are described in more detail below.

[0024] The compositions of the present specification may optionally include one or more additional skin actives or other components of the types commonly included in topical skin care compositions. For example, the compositions of the present specification may include a skin softening agent or an aliphatic alcohol (e.g., hexyldecanol) that acts as a skin softening agent. When the composition includes an aliphatic alcohol, the combination of sucrose ester and aliphatic alcohol may be selected to provide a synergistic improvement in cellular ATP production, as described, for example, in co-pending U.S. Patent Application No. 63 / 125,011, filed December 14, 2020, by Hakozaki et al. and entitled "Method of Treating Oxidative Stress in Skin and Compositions Therefor".

[0025] The skin care compositions of the present specification may be prepared using conventional methods. However, in some cases, it may be difficult to solubilize the sucrose ester in the composition using conventional methods. In these cases, it may be desirable to solubilize the sucrose ester in a two-step dilution process using a glycol premix or other suitable solubilizing agent and then add this to the composition. An example of this process is described in co-pending U.S. Patent Application No. 63 / 124,870, filed December 14, 2020, by Tanaka et al. and entitled "Cosmetic Compositions Comprising Sucrose Esters and Solvents".

[0026] In contrast to similar types of skin compositions known to have a surfactant system with an HLB of 12 or higher (e.g., greater than 13, 14, or 15), the compositions herein may have a surfactant system with an HLB of less than 10. In comparative compositions, when the HLB of the surfactant system drops below 10, the composition (i.e., the emulsion) can become unstable. However, as shown in the examples below, simply adjusting the HLB value is not sufficient to overcome the instability observed when sucrose esters are present in the composition. Therefore, it can be important to specifically select a suitable combination of components to ensure emulsion stability.

[0027] The compositions herein may be cosmetic compositions, pharmaceutical compositions, or cosmeceutical compositions suitable for use in keratinous tissues (e.g., skin, hair, and nails), and may be provided in various product forms including, but not limited to, solutions, suspensions, lotions, creams, gels, toners, sticks, sprays, aerosols, ointments, cleansing liquid cleansers and solid bars, pastes, foams, mousses, shaving creams, wipes, strips, patches, electric patches, hydrogels, film-forming products, facial and skin masks (with and without insoluble sheets), foundations, eyeliners, and eye shadows, etc. makeup. In some cases, the form of the composition may follow a particular dermatologically acceptable carrier selected (i.e., an oil-in-water (O / W) emulsion). It may be particularly desirable to provide the present composition as a skin cream, lotion, serum, or essence.

[0028] Sucrose ester The compositions of the present specification contain an effective amount of an ester of sucrose and a fatty acid, and the fatty acid is selected from those having 12 to 24 carbon atoms (for example, 12 to 22 carbon atoms or 12 to 18 carbon atoms). Particularly suitable fatty acids can be selected from those having a saturated alkyl group. In some cases, the sucrose ester is selected from the group consisting of sucrose laurate, sucrose dilaurate, sucrose trilaurate, derivatives thereof, and combinations thereof. As used herein, "sucrose laurate" means a compound having the formula C 24 H 44 O 12 and CAS#25339-99-5. "Sucrose dilaurate" means a compound having the formula C 36 H 66 O 13 and CAS#25915-57-5, and "sucrose trilaurate" means a compound having the formula C 48 H 88 O 14 and CAS#94031-23-9. The sucrose ester may be present in the composition at 0.0001 wt% to 15 wt% (for example, 0.0002 wt% to 10 wt%, 0.001 wt% to 15 wt%, 0.025 wt% to 10 wt%, 0.05 wt% to 7 wt%, 0.05 wt% to 5 wt%, or even 0.1 wt% to 3 wt%).

[0029] In some cases, the sucrose ester may be a blend of two or more sucrose esters, and the two or more sucrose esters may be present in a ratio of 1:10 to 1:1 (e.g., 1:7, 1:5, 1:3, or 1:2) of any one sucrose ester to another sucrose ester. In some cases, the sucrose ester may be a blend of sucrose laurate and sucrose dilaurate, where sucrose laurate is present at 50 wt% to 80 wt% of the sucrose ester and sucrose dilaurate is present at 20 wt% to 45 wt% of the sucrose ester. Alternatively, the sucrose ester may be a blend of sucrose laurate, sucrose dilaurate, and sucrose trilaurate, where sucrose dilaurate is present at 35 wt% or more of the sucrose ester. A particularly preferred example of the sucrose ester for use herein is BC10034 from BASF®, which is a blend of sucrose laurate and sucrose dilaurate. The BC10034 sucrose ester material may have a ratio of sucrose laurate to sucrose dilaurate in the range of 3:1 to 3:2.

[0030] Dermatologically acceptable carrier The compositions disclosed herein include a dermatologically acceptable carrier (sometimes referred to as a "carrier"). The phrase "dermatologically acceptable carrier" means that the carrier is suitable for topical application to keratinous tissues, has good aesthetic properties, is compatible with the active substances in the composition, and does not give rise to any undue concerns regarding safety or toxicity. In one embodiment, the carrier is present at a level of about 50 wt% to about 99 wt%, about 60 wt% to about 98 wt%, about 70 wt% to about 98 wt%, or alternatively about 80 wt% to about 95 wt%.

[0031] The carrier in this specification is in the form of an oil-in-water emulsion. That is, the emulsion has a continuous aqueous phase and a dispersed oil phase. The oil phase may include silicone oil, non-silicone oil (such as hydrocarbon oil, ester, ether, etc.), and mixtures thereof. The aqueous phase may include water and / or water-soluble or water-miscible components (such as polyols like ethanol, glycerin, humectants, conditioning agents, antibacterial agents, wetting agents, and / or other skin care actives). The O / W emulsion can provide a light and non-greasy sensory feel. A preferred O / W emulsion in this specification may include a continuous aqueous phase of more than 50% by weight of the composition, and the balance may be the dispersed oil phase. The aqueous phase may include 1% to 99% water based on the weight of the aqueous phase together with any water-soluble and / or water-miscible components. In these cases, the dispersed oil phase will typically be present at less than 30% by weight of the composition (such as 1% to 20%, 2% to 15%, 3% to 12%, 4% to 10%, or even 5% to 8%) to help avoid some of the undesirable tactile effects of the oily composition. The oil phase may include one or more volatile and / or non-volatile oils (such as vegetable oil, silicone oil, and / or hydrocarbon oil). Some non-limiting examples of oils that may be suitable for use in this composition are disclosed in U.S. Patent No. 9,446,265 and U.S. Patent Application Publication No. 2015 / 0196464.

[0032] The carrier may contain one or more dermatologically acceptable hydrophilic diluents. As used herein, "diluent" includes materials that can disperse, dissolve, or otherwise incorporate materials such as sucrose esters. Hydrophilic diluents include water, lower monohydric alcohols (such as C 1 ~C 4) and organic hydrophilic diluents such as low molecular weight glycols and polyols, including propylene glycol, polyethylene glycol (e.g., molecular weight 200 - 600 g / mol), polypropylene glycol (e.g., molecular weight 425 - 2025 g / mol), glycerol, butylene glycol, 1,2,4 - butanetriol, sorbitol ester, 1,2,6 - hexanetriol, ethanol, isopropanol, sorbitol ester, butanediol, ether propanol, ethoxylated ether, propoxylated ether, and combinations thereof.

[0033] Rheology modifier The compositions of the present specification contain 0.05% - 5% of a hydrophobically modified aqueous rheology modifier (e.g., a thickening agent) to provide the compositions with suitable rheology, stability, and skin feel characteristics. Some non - limiting examples of rheology modifiers that may be suitable for use in the present specification include cross - linked polyacrylate polymers such as PEMULEN EZ - 4U, PEMULEN TR - 1, PEMULEN TR - 2, and certain ULTREZ brand acrylate / C10 - 30 alkyl acrylate crosspolymers (all available from Lubrizol®). Other examples include acrylate vinyl isodecanoate crosspolymers such as STABYLEN 30 sold by 3V Sigma®, polyacrylate crosspolymer - 6 such as SEPIMAX ZEN sold by Seppic®, and sodium polyacryloyldimethyltaurate such as ARISTOFLEX SILK sold by Clariant. In some cases, polyacrylamide - based thickeners such as the SEPIGEL 305 brand polyacrylamide thickener may destabilize the emulsion, so it may be desirable to exclude these types of thickeners.

[0034] The rheology modifier of the composition of the present specification may contain medium-chain to long-chain fatty acid derivative emulsifiers (for example, fatty acid chains of about 12 to 20 carbons, alternatively 16 to 20 carbons). In some examples, the emulsifier may include nonionic medium-chain to long-chain fatty acid derivative emulsifiers such as steareth-2, steareth-21, PEG-100 stearate, glyceryl-25 pyrrolidone carboxylic acid isostearate, and combinations thereof. The "emulsifier derived from stearic acid" refers to an emulsifier in which at least one of the lipophilic domains of the surfactant is composed of a saturated 18-carbon chain (similar to stearic acid). These emulsifiers typically contain stearate, steareth, or isostearate in their chemical names and are often derived from stearic acid combined with other chemical moieties. Particularly preferred emulsifiers include stearic acid-derived emulsifiers having a hydrophilic-lipophilic balance (HLB) of 14 or more. The emulsifier may be present in the composition at 0.05% to 5% (for example, 0.1% to 4%, 0.5% to 3%, or even 1% to 2%). In some cases, it may be desirable to exclude certain polyether-modified silicone emulsifiers such as PEG-11 methyl ether dimethicone, PEG-12 dimethicone, PEG / PPG 19 / 19 dimethicone, or other PEGylated dimethicones that can destabilize the oil-in-water emulsion.

[0035] Optional component. The compositions of the present specification may include one or more optional components known for use in topical skin care compositions, provided that the optional components do not alter such that they cannot tolerate the desired benefits of the present composition. Specifically, the optional components should not introduce unwanted instability to the emulsion. For example, it may be desirable to select optional components that do not form complexes with other components in the composition, particularly pH-sensitive components such as vitamin B3 compounds, salicylates, and peptides. When optional skin care actives are included in the present composition, it may be desirable to select skin care actives that function via a biological pathway different from other skin actives present in the composition such that the actives do not interfere with each other.

[0036] Optional components, if included, must be suitable for use in contact with human skin tissue without undue toxicity, incompatibility, instability, allergic response, etc. If present, optional components may be included in an amount of about 0.001 wt% to 50 wt% (e.g., 0.01 wt% to 40 wt%, 0.1 wt% to 30 wt%, 0.5 wt% to 20 wt%, or 1 wt% to 10 wt%) of the composition. Some non-limiting examples of additional components include vitamins, minerals, peptides and peptide derivatives, sugar amines, sunscreens, oil control agents, microparticles, flavonoid compounds, hair growth regulators, antioxidants and / or antioxidant precursors, preservatives, protease inhibitors, tyrosinase inhibitors, anti-inflammatory agents, moisturizers, keratolytic agents, skin whitening agents, sunburn preventives, sunless tanning agents, lubricants, anti-acne agents, anti-cellulite agents, chelating agents, anti-wrinkle active substances, anti-atrophy active substances, phytosterols and / or phytohormones, N-acyl amino acid compounds, antibacterial agents, and antifungal agents. Some particularly preferred examples of additional components include one or more skin care active substances selected from the group consisting of vitamin B3 compounds (e.g., niacinamide), n-acyl amino acids (e.g., undecylenoyl phenylalanine), vitamin E compounds (e.g., tocopheryl acetate), palmitoylated dipeptides (e.g., palmitoyl-lysine-threonine), palmitoylated pentapeptides (e.g., palmitoyl-lysine-threonine-threonine-lysine-serine), vitamin A compounds (e.g., retinol and retinyl propionate), and combinations thereof.Other non-limiting examples of optional components and / or skin care active substances that may be suitable for use in this specification are described in U.S. Patent Application Publication Nos. 2002 / 0022040, 2003 / 0049212, 2004 / 0175347, 2006 / 0275237, 2007 / 0196344, 2008 / 0181956, 2008 / 0206373, 2010 / 0092408, 2008 / 0206373, 2010 / 0239510, 2010 / 0189669, 2010 / 0272667, 2011 / 0262025, 2011 / 0097286, 2012 / 0197016, 2012 / 0128683, 2012 / 0148515, 2012 / 0156146, and 2013 / 0022557, as well as U.S. Patents Nos. 5,939,082, 5,872,112, 6,492,326, 6,696,049, 6,524,598, 5,972,359, and 6,174,533.

[0037] In some cases, it may be desirable to include aliphatic alcohols in the skin care composition. At least some aliphatic alcohols function as skin softeners, which helps to moisturize the skin. Additionally or alternatively, some aliphatic alcohols such as hexyl decanol may improve the penetration of certain skin active substances (e.g., vitamin B 3 compounds) into the skin and / or may independently provide benefits to the health or appearance of the skin. Aliphatic alcohols are high molecular weight straight-chain primary alcohols having the following general structure,

[0038]

Chemical formula

[0039] Aliphatic alcohols may be natural or synthetic, saturated or unsaturated, branched or straight-chain. Some non-limiting examples of aliphatic alcohols commonly used in skin care compositions include caprylic, capryl, lauryl, myristyl, cetyl, stearyl, and behenyl alcohol. The aliphatic alcohols herein may be generically referred to by the number of carbon atoms in the molecule. For example, "C12 alcohol" refers to an alcohol having 12 carbon atoms in its chain (i.e., dodecanol). Some aliphatic alcohols particularly suitable for use herein include ricinoleate, 12-hydroxystearate, and hexyl decanol. The aliphatic alcohol may be included in the compositions herein at 0.0001% to 15% by weight of the composition (e.g., 0.0002% to 10% by weight, 0.001% to 15% by weight, 0.025% to 10% by weight, 0.05% to 7% by weight, 0.05% to 5% by weight, or even 0.1% to 3% by weight).

[0040] Conditioning agent The compositions of the present specification may contain from 0.1% to 50% by weight of a conditioning agent (e.g., from 0.5% to 30%, from 1% to 20%, or even from 2% to 15%). Adding a conditioning agent can help provide the composition with desirable tactile properties (e.g., a smooth silk-like feel upon application). Some non-limiting examples of conditioning agents include hydrocarbon oils and waxes, silicones, fatty acid derivatives, cholesterol, cholesterol derivatives, diglycerides, triglycerides, vegetable oils, vegetable oil derivatives, acetoglyceride esters, alkyl esters, alkenyl esters, lanolin, wax esters, beeswax derivatives, sterols and phospholipids, their salts, isomers, and derivatives, and combinations thereof. Particularly preferred examples of conditioning agents include volatile or non-volatile silicone fluids such as dimethicone copolyol, dimethylpolysiloxane, diethylpolysiloxane, mixed C1-30 alkylpolysiloxane, phenyl dimethicone, dimethiconol, dimethicone, dimethiconol, silicone crosspolymer, and combinations thereof. Dimethicone may be particularly preferred, as some consumers associate the tactile properties provided by certain dimethicone fluids with good moisturization. Other examples of silicone fluids that may be suitable for use as conditioning agents are described in U.S. Patent No. 5,011,681.

[0041] Method of Use The method includes identifying a target portion of the keratinous tissue (e.g., skin or hair) of a person to be treated and applying an effective amount of a composition to the target portion over the course of a treatment period. The target portion of the keratinous tissue may be the facial skin surface such as the forehead, around the mouth, jaw, around the eye sockets, nose, and / or cheeks), or another body part (e.g., hands, arms, legs, back, chest). The target portion of the skin to be treated may be a portion exhibiting signs of oxidative stress or aging such as fine lines, wrinkles, hyperpigmentation, uneven skin tone, and / or other visible skin features typically associated with aging. In some cases, the target portion of the skin may not exhibit visible signs of skin aging, but if the target portion is such that a person typically develops such problems as they age, a user (e.g., a relatively young user) may still desire to target that skin area. In this way, the method may be used as a preventive means for delaying the onset of visible signs of skin aging.

[0042] The skin care composition herein may be applied daily to the target portion of the skin and, if desired, to the surrounding skin at least once a day, twice a day, or more frequently during the treatment period. When applying twice a day, an interval of at least 1 to 12 hours is left between the first and second applications. Typically, the composition is applied in the morning and / or before bedtime at night. When used according to the method herein, the composition may improve the appearance of skin affected by oxidative stress, for example, by increasing ATP production in skin cells.

[0043] The treatment period of the present specification is, ideally, a time sufficient for the combination of sucrose ester and aliphatic alcohol present in the composition to increase ATP production in skin cells under oxidative stress, thereby improving the appearance of visible signs of skin aging. The benefit of ATP production provided by the present method can be shown by a synergistic increase in ATP production as compared to the case of using sucrose ester and aliphatic alcohol individually. In some cases, the present method can provide a synergistic increase in ATP production of at least 5% (e.g., 10%, 15%, 20%, 25%, or more) as compared to the predicted increase in ATP production. The treatment period can last for at least 1 week (e.g., about 2 weeks, 4 weeks, 8 weeks, or even 12 weeks). In some cases, the treatment period will extend over several months (i.e., 3 to 12 months). In some cases, the composition can be applied at least once a day, or even twice a day, over most days of the week (e.g., at least 4 days, 5 days, or 6 days per week) during a treatment period of at least 2 weeks, 4 weeks, 8 weeks, or 12 weeks.

[0044] The step of applying the composition may be achieved by topical application. With respect to the application of the composition, the terms "topical", "topically", or "locally" mean that the composition is delivered to the target area (e.g., wrinkles or fine lines) while minimizing delivery to skin surfaces where treatment is not desired. The composition may be applied to a skin area and gently rubbed in. The form of the composition or dermatologically acceptable carrier should be selected to facilitate topical application. While certain embodiments of the present specification contemplate topical application of the composition to an area, it should be understood that the compositions of the present specification can be applied extensively to one or more skin surfaces. In certain embodiments, the compositions of the present specification may be used as part of a multi-step beauty method, in which the present composition may be applied before and / or after one or more other compositions.

[0045] Optical centrifugation test This test method provides a way to evaluate the emulsion stability of a sample using a dispersion analyzer (e.g., a dispersion analyzer of the LUMiSizer (trademark) brand from LUM GMBH) with baseline and high-temperature aging over time. The sample is placed in a container suitable for testing (e.g., LUM 2mm, polycarbonate rectangular synthetic cell cuvette (LUM GMBH: 110 - 131xx)) and run at 40 °C and 4000 rpm for 1 hour. The accelerated stability test using photo-centrifugation technology is well documented in the literature (e.g., References: Badolato, G.G., et al. "Evaluation of long-term stability of model emulsions by multi-sample analytical centrifugation." Surface and interfacial forces - from fundamentals to applications. Springer, Berlin, Heidelberg, 2008. 66 - 73). This method involves centrifuging the sample while irradiating it with near-infrared or blue light parallel to the entire sample cell. The transmitted light is detected by a CCD sensor and converted into an extinction profile. Changes in light transmittance during centrifugation indicate multiple instability mechanisms such as sedimentation, creaming, aggregation, and / or emulsion coalescence. For emulsions, both sedimentation and creaming can be observed by increasing the transmittance either at the top (sedimentation) or at the bottom (creaming) of the sample, based on the relative density of the phase separation. For example, Figure 1 shows an O / W emulsion exhibiting sedimentation, which is observed as a low-density oil separating from the remaining emulsion under centrifugation at the top of the sample. In contrast, Figure 2 shows an example of a stable O / W emulsion.

[0046] The instability of an emulsion measured via opto-centrifugation can be quantified by an instability index (Detloff, T., T. Sobisch, and D. Lerche. "Instability index." Dispersion Letters Technical 4 (2013): 1-4.). The instability index is based on the increase in light transmittance, also known as clarification, which is caused by either sedimentation or creaming. The index is a dimensionless number between 0 and 1, where "0" indicates no change during centrifugation and complete stability, and "1" indicates complete instability as shown by the change in light transmittance across the region of interest. The dimensionless index can be multiplied by 100% to express the instability index as a percentage. This index provides a relative ranking of the stability for the different samples tested. The measured instability index can be normalized against a negative control to provide a more useful indicator of emulsion stability.

[0047] The instability index can be calculated using a suitable software tool (e.g., SEPView® software or equivalent) according to the following equations. Equation 1 is used to calculate the clarification (the difference between the initial transmittance and the subsequent transmittance). Equation 2 is used to calculate the change in clarification up to a specific time for profile i, which is calculated as the sum of the incremental clarifications within the region of interest. Equation 3 is used to calculate the maximum possible clarification. Equation 4 calculates the instability index as the change in transmittance divided by the maximum possible change within the region of interest.

[0048]

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[0049]

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[0050]

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[0051]

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[0052]

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[0053]

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[0054] As can be seen from the formula, the instability index is a relative ranking based on the region of interest with respect to the maximum clarification possible in the region of interest. For the instability index measurements reported herein, since the absolute value of the instability index is affected by the selected region of interest, the region of interest is taken for the entire sample cell. As a result, relative comparisons for a given region of interest may be of more interest than the reported absolute values. The relative comparison can be provided by normalizing the observed instability index with respect to a control.

[0055] In addition to the instability index, the rate of change of the instability index indicates the separation kinetics. This can be evaluated by plotting the instability index against time. This rate of change is also related to the rate of sedimentation or creaming that can be quantified based on Stokes' law. As described above, the sedimentation rate is defined by Stokes' law as shown in Equation 5. In the formula, v is the velocity, ρ is the density, r is the particle size, η is the dynamic viscosity of the continuous phase, g is the gravity, α is the particle concentration, and RCA is the relative centrifugal acceleration.

[0056]

Number

[0057] Although not limited by theory, the main cause of emulsion instability is the change in the droplet radius r from the coalescence caused by the sucrose ester, which is considered to correlate with a faster sedimentation rate.

[0058] Examples and Combinations Example 1: Formulation Table 1 below provides examples of stable emulsion skin care compositions containing sucrose esters. The exemplary compositions can be prepared as follows. A sucrose ester premix is prepared by combining sucrose ester, pentylene glycol, and water and mixing until the sucrose ester is completely dissolved. Heat may be used if necessary to assist in the dissolution of the sucrose ester. Separately, an aqueous phase is prepared by dispersing a thickener and a polymeric emulsifier in the aqueous phase. After the thickener is dispersed and homogenized, any additional emulsifier (e.g., a high HLB emulsifier) is added to the aqueous phase. The remaining aqueous phase components are added and the pH is adjusted as desired (e.g., pH 5 - 7). In a separate container, the oil phase components are combined and mixed while heating if necessary (e.g., to melt any solid materials) until homogeneous. Next, the oil phase is emulsified into the aqueous phase by slowly adding the oil phase with mixing, and mixing is continued until the emulsion is completely homogeneous. After the emulsion is completely homogeneous, any remaining components are added with mixing until homogeneous. The sucrose ester premix phase can be added to the batch either before or after the emulsification step and then mixed until the batch is homogeneous.

[0059] [Table 1-1]

[0060] [Table 1-2]

[0061]

Table 2

[0062] Example 2 - Variation of instability index This example shows the effect on the instability index of various emulsifiers and rheology modifiers. In this example, stability test samples were prepared as described in Example 1 and tested according to the above-described photo-centrifugation method. The instability index was quantified by selecting the regions of interest at the air / liquid interface and at the bottom of the sample for whole cell analysis using software of the Lum GMBH SEPView® brand. After aging at 50 °C for 2 weeks, the instability index values of each test composition and the control were determined. As described above, a stable emulsion has an instability index of less than 5% (e.g., less than 4%, less than 3%, less than 2%, less than 1%, or even less than 0.5%). A partially stable emulsion is seen when minimal oil separation is observed in the sample after the photo-centrifugation test and / or there is creaming, typically observed in the range of 2.5% - 5% of the instability index. A very stable emulsion is seen when no oil separation is observed in the sample after the photo-centrifugation test, typically observed in the range of less than 2.5%, alternatively less than 2%. Partially stable emulsions may be acceptable to consumers but may be slightly less preferred compared to very stable emulsions. The compositions tested are listed in Table 2 below. Composition A, which does not contain a non-ionic stearic acid-derived emulsifier, is used as a negative control. The results of the instability index were normalized against the negative control.

[0063]

Table 3-1

[0064]

Table 3-2

[0065] The results of the tests are summarized in Table 3 below and shown in Figure 3. As seen in Table 3 and Figure 3, Composition H of the present invention containing a suitable combination of sucrose esters, hydrophobically modified polymer thickeners (e.g., Pemulen (trademark)), and nonionic stearic acid-derived emulsifiers was the most stable composition compared to the comparative examples. Composition H exhibited an instability index of less than 1% and a relative instability index of less than 5% when normalized against the negative control.

[0066] Example C was also stable and, in combination with sucrose dilaurate, had a lower level of hexyl decanol compared to A and B.

[0067] Partially stable formulations were observed by using nonionic stearic acid-derived emulsifiers in the presence of reduced hydrophobically modified polymer thickener Carbopol Ultrez 20 (trademark), which was less effective the more hydrophobically modified polymer Pemulen TR-1 (trademark) was increased.

[0068]

Table 4

[0069] Example 3 - Sucrose esters destabilize the O / W emulsion. This example demonstrates the destabilizing effect that sucrose esters can have on an O / W emulsion skin care composition by comparing a test composition containing sucrose dilaurate with a control composition that does not contain sucrose dilaurate. Both the test composition and the control composition are O / W emulsions and were identical in all respects except that the test composition contained 1% sucrose dilaurate (BC10034 from BASF®). The compositions were prepared according to the method described in Example 1 and tested according to the light centrifugation test described above. Samples were prepared in a LUM 2 mm polycarbonate rectangular synthesis cell and run on a LUMISIZER® brand dispersion analyzer at 4000 RPM for 1 hour at a constant temperature of 40 °C while measuring and sampling every 10 seconds. Analysis was performed using Lum GMBH SEPView® software and the instability index was quantified by selecting the relevant region of interest for all sample cells. The instability index values for each composition were determined after aging at 50 °C for 2 weeks as in the previous examples. The results of the test are summarized in Table 4 below. As can be seen in Table 4, the addition of sucrose esters to the O / W emulsion composition resulted in significant instability compared to the control.

[0070]

Table 5

[0071] Example 4 - Importance of the selection of rheology modifiers and emulsifiers. This example shows the importance of selecting suitable rheology modifiers and emulsifiers to overcome the instability of emulsions caused by sucrose esters. The dosage response of polysorbate - 20, a well - known ethoxylated sorbitol ester emulsifier, was carried out to re - balance the existing sucrose dilaurate and HLB. It was found that a simple re - balancing of the HLB of the emulsifier with polysorbate - 20 was insufficient to stabilize the oil - in - water emulsion even at a 10% polysorbate - 20 level, as shown in Tables 5 and 6. Also, it was found that using a hydrophobically modified rheology modifier such as Pemulen TR - 1 (trademark) alone was not sufficient to fully stabilize the emulsion. Surprisingly, the combination of a hydrophobically modified rheology modifier (e.g., Pemulen (trademark), Stabylen 30 (trademark), Sepimax Zen (trademark), Aristoflex Silk (trademark)) and a stearic acid derivative emulsifier (e.g., PEG - 100 stearate, stearess - 2 / stearess - 21 blend, and / or glyceryl - 25 PCA isostearate) was able to properly stabilize the emulsion, and it was found that combining the hydrophobically modified rheology modifier with the stearic acid derivative emulsifier in a specific combination resulted in an improved dosage response of increasing stability, as shown in Table 7.

[0072] The HLB experimental compositions are shown in Table 5. The basic formulation was modified by varying the level of polysorbate - 20. Test samples of each composition were prepared according to the method described in Example 1 and tested according to the above - mentioned light centrifugation test method. The basic composition does not contain sucrose ester, while the test compositions contain 1% sucrose ester and various amounts of polysorbate - 20. The results of the tests are summarized in Table 6.

[0073] [Table 6] + Balance it to pH 5.5 to 6.5. * Sucrose Ester (SE) premix was used only in the test composition. 1. ELDEW PS-203 available from Ajinomoto (registered trademark) 2. KSG-16 available from Shin-Etsu (registered trademark) 3. KF-6011 available from Shin-Etsu (registered trademark) 4. BC10034 available from BASF (registered trademark) 5. CARBOPOL ULTREZ 20 available from Lubrizol (registered trademark) 6. SEPIGEL 305 available from Seppic (registered trademark) 7. SEPIWHITE available from Seppic (registered trademark)

[0074]

Table 7

[0075] Table 7A, Table 7B, and Table 7C provide compositions of additional examples and comparative examples of the present invention and show the importance of selecting appropriate combinations of sucrose esters, hydrophobically modified aqueous rheology modifiers, and non-ionic stearic acid-derived emulsifiers. Composition A is used as a positive control, and Composition B is used as a negative control. The example compositions in Tables 7A to 7C were prepared using the methods described herein.

[0076]

Table 8

[0077]

Table 9

[0078]

Table 10

[0079] In addition to determining the instability indices of Compositions A - T, visual observations were also made to explain the emulsion stability or instability. The following Table 7D provides a summary of the visual observations made for each composition.

[0080]

Table 11

[0081] The dimensions and values disclosed in this specification should not be understood to be strictly limited to the exact numerical values recited. Instead, unless otherwise indicated, each such dimension is intended to mean both the recited value and the functionally equivalent range surrounding that value. For example, a dimension disclosed as "40 mm" is intended to mean "about 40 mm".

[0082] All documents cited herein, including any patents or patent applications that are cross-referenced or related, and any patent applications or patents for which this application claims priority or the benefit thereof, are hereby incorporated by reference in their entirety, unless expressly excluded or limited. The citation of any document shall not be construed as an admission that such document is prior art with respect to any invention disclosed or claimed herein, or that it teaches, suggests, or discloses any such invention, either alone or in combination with any other reference(s). Further, in the event of any conflict between any meaning or definition of a term in this document and any meaning or definition of the same term in a document incorporated by reference, the meaning or definition given to the term in this document shall apply.

[0083] Although specific embodiments of the invention have been illustrated and described, it will be apparent to those skilled in the art that various other changes and modifications can be made without departing from the spirit and scope of the invention. Accordingly, all such changes and modifications that fall within the scope of the invention are intended to be covered by the appended claims.

Claims

1. A skin care composition with improved emulsion stability, comprising: a) 0.0001% to 10% by weight of a sucrose ester selected from sucrose laurate, sucrose dilaurate, sucrose trilaurate, and combinations thereof; b) 0.30% to 5% by weight of a hydrophobically modified aqueous rheology modifier; c) 0.005% to 5% by weight of a nonionic fatty acid derivative emulsifier; d) a dermatologically acceptable carrier in the form of an oil-in-water emulsion; e) 0.0001% to 10% by weight of an aliphatic alcohol and wherein the sucrose ester comprises 50% to 80% by weight of sucrose laurate and 20% to 45% by weight of sucrose dilaurate of the sucrose ester; wherein the hydrophobically modified aqueous rheology modifier is an acrylate-based rheology modifier, and the acrylate-based rheology modifier is selected from the group consisting of acrylate / C10-30 alkyl acrylate crosspolymer, acrylate isodecyl vinyl crosspolymer, and combinations thereof; wherein the nonionic fatty acid derivative emulsifier is selected from the group consisting of steareth-2, steareth-21, PEG-100 stearate, and glyceryl isostearate pyrrolidone carboxylate; wherein the carrier comprises a dispersed oil phase and a continuous aqueous phase, and the continuous aqueous phase comprises a water-soluble or water-miscible component selected from the group consisting of water and / or ethanol, polyol, humectant, conditioning agent, antibacterial agent, wetting agent, and / or other skin care active substances; A skin care composition wherein the aliphatic alcohol is hexyl decanol.

2. The skin care composition according to claim 1, which exhibits an instability index value of less than 10% according to the photocentrifugation test.

3. The skin care composition according to claim 2, which exhibits a normalized instability index value of less than 20% compared to the negative control.

4. The skin care composition according to any one of claims 1 to 3, wherein the composition does not contain a polyether-modified silicone emulsifier.

5. The skin care composition according to any one of claims 1 to 4, further comprising an additional component selected from the group consisting of vitamins, minerals, peptides, sugar amines, sunscreen agents, oil control agents, flavonoid compounds, antioxidants, preservatives, protease inhibitors, tyrosinase inhibitors, anti-inflammatory agents, humectants, keratolytic agents, skin whitening agents, lubricants, anti-acne active substances, chelating agents, anti-wrinkle active substances, anti-atrophy active substances, phytosterols, N-acyl amino acid compounds, antibacterial agents, and antifungal agents, conditioning agents, emulsifiers, rheology modifiers, and combinations thereof.

6. The skin care composition according to claim 5, wherein the additional component is a skin care active substance selected from the group consisting of vitamin B3 compounds, undecylenoyl phenylalanine, vitamin E compounds, palmitoylated dipeptides, palmitoylated pentapeptides, vitamin A compounds, and combinations thereof.

7. The skin care composition according to claim 6, further comprising an emulsifier selected from the group consisting of PEG-100 stearate, steareth-2, steareth-21, and glyceryl isostearate pyrrolidone carboxylate.

8. A method for cosmetically treating skin, comprising: a) identifying a target portion of the skin to be treated; and b) applying the composition according to any one of claims 1 to 7 to the target portion of the skin over the course of a treatment period.

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