Self-tanning compositions and methods containing aromatic sulfonates

Abstract

The present disclosure provides a topical skin care composition comprising (A) a reducing sugar, (B) an aromatic sulfonate having a topological polar surface area (tPSA) less than 100 μm, and (C) a carrier. Also provided is a method for regulating skin color appearance (e.g., hue angle, brightness, saturation), comprising applying the topical skin care composition to the skin. The topical skin care composition, when applied to the skin, can provide a deep, rich, long-lasting sunless tan with an aesthetically pleasing red / bronze hue.

Description

Technical Field

[0001] The present invention relates to a topical skin care composition, in particular, to a topical skin care composition comprising (A) a reducing sugar, (B) an aromatic sulfonate, and (C) a carrier, and a self-tanning method using the topical skin care composition. Background Art

[0002] The "Background Art" section provided herein is for the purpose of summarizing the background of the present disclosure. The work of the named inventors of this application, as well as any description that may not qualify as prior art at the time of filing, is not intended, either explicitly or implicitly, to be admitted as prior art against the present invention, within the scope of this background art section.

[0003] Consumers around the world enjoy spending time in the sun for many reasons, including outdoor recreation, sports, and tanning (darkening of skin color). Unfortunately, exposure to UV radiation is known to have the potential to promote skin cancer. Furthermore, some exposure to UV radiation can lead to uneven skin tone throughout the body. Therefore, there are health and aesthetic incentives for alternative methods that can achieve a natural-looking, even skin tone while avoiding the dangers of sun exposure.

[0004] Despite the known risks, sunbathing remains the most common method of darkening the skin in the United States and the European Union (EU). Sunless tanners and matte moisturizers are also common methods, but many consumers are dissatisfied with these products because the color is often considered unnatural, not dark enough, or fades quickly. For example, many conventional self-tanning products that use dihydroxyacetone (DHA) as a tanning agent produce an undesirable orange tint. In addition to darkening the skin tone, effective tone adjustment is also needed to produce a noticeable tan with a bronze / reddish hue.

[0005] Several skin tanning formulations that utilize azole compounds, pigments (e.g., carmine), cross-linked cationic copolymers, and vanillin polymers to enhance skin coloration have been reported ( U.S. Pat. No. 5,705,145 , U.S. Pat. No. 6,214,322 , U.S. Pat. No. 7,780,954 , and U.S. Pat. No. 7,935,331 , each of which is incorporated herein by reference in its entirety). However, there remains a need for improved formulations that can effectively darken skin tone and transform skin hue. Summary of the Invention

[0006] In view of the foregoing, there exists a need for long-lasting topical skin care compositions that produce darker colors and more pronounced bronze / red tones.

[0007] It is therefore an object of the present invention to provide new topical skin care compositions that meet these criteria.

[0008] Another object of the present invention is a novel method for adjusting the color appearance (eg, brightness, hue angle, saturation) of a subject's skin by topically applying a topical skin care composition to the subject's skin.

[0009] These and other objects that will become apparent from the detailed description below are achieved by the inventors' discovery that the combination of a reducing sugar, an aromatic sulfonate, and a carrier unexpectedly produces a topical skin care composition that promotes a long-lasting, rich, and intense (i.e., dark) tan characterized by a desirable bronze / red hue.

[0010] Therefore, the present invention provides:

[0011] (1) A topical skin care composition comprising:

[0012] (A) about 0.1 to 30 weight % of a reducing sugar relative to the total weight of the topical skin care composition;

[0013] (B) an alkali metal aromatic sulfonate; and

[0014] (C) a carrier,

[0015] The topological polar surface area (tPSA) of the alkali metal aromatic sulfonate (B) is less than and

[0016] The weight ratio of the alkali metal aromatic sulfonate (B) to the reducing sugar (A) ((B):(A)) is 1:20 to 20:1.

[0017] (2) The topical skin care composition according to (1), wherein the alkali metal aromatic sulfonate (B) is an optionally substituted phenyl sulfonate, an optionally substituted naphthyl sulfonate, or both.

[0018] (3) The topical skin care composition according to (1) or (2), wherein the alkali metal aromatic sulfonate (B) has no more than 2 hydrogen bond donor sites.

[0019] (4) The topical skin care composition according to any one of (1) to (3), wherein the alkali metal aromatic sulfonate (B) is sodium 2-naphthalenesulfonate.

[0020] (5) The topical skin care composition according to any one of (1) to (3), wherein the alkali metal aromatic sulfonate (B) is sodium p-toluenesulfonate.

[0021] (6) The topical skin care composition according to any one of (1) to (3), wherein the alkali metal aromatic sulfonate (B) is sodium cumene sulfonate.

[0022] (7) The topical skin care composition according to any one of (1) to (6), wherein the reducing sugar (A) is dihydroxyacetone, erythrulose, or both.

[0023] (8) The topical skin care composition according to any one of (1) to (7), wherein the carrier (C) comprises an aromatic alcohol.

[0024] (9) The topical skin care composition according to any one of (1) to (8), wherein the carrier (C) comprises benzyl alcohol.

[0025] (10) The topical skin care composition according to any one of (1) to (9), further comprising (D) an organic solvent.

[0026] (11) The topical skin care composition according to (10), wherein the organic solvent (D) comprises a polyol.

[0027] (12) The topical skin care composition as described in (11), wherein the polyol is at least one selected from 1,3-propylene glycol, 1,2-propylene glycol, ethylene glycol, glycerol and 1,3-butylene glycol.

[0028] (13) The topical skin care composition according to any one of (10) to (12), wherein the weight ratio of the carrier (C) to the organic solvent (D) ((C):(D)) is from 1:20 to 1:2.

[0029] (14) A topical skin care composition as described in any one of (1) to (13), wherein the weight ratio of the alkali metal aromatic sulfonate (B) to the carrier (C) ((B):(C)) is 1:4 to 4:1.

[0030] (15) The topical skin care composition according to any one of (1) to (14), which is substantially free of a cationic copolymer.

[0031] (16) The topical skin care composition according to any one of (1) to (15), which is in the form of a lotion, cream, gel, spray or foam.

[0032] (17) A method for regulating the skin color of a subject, the method comprising:

[0033] topically applying the topical skin care composition of any one of (1) to (16) to the skin of a subject,

[0034] wherein the topical application reduces or increases the hue angle h° of the color by at least 0.5° compared to before the topical application.

[0035] (18) A method for adjusting the skin color of a subject, the method comprising:

[0036] topically applying the topical skin care composition of any one of (1) to (16) to the skin of a subject,

[0037] The topical application reduces the lightness L* of the color by at least 10% and reduces or increases the hue angle h° of the color by at least 0.5°, respectively, compared to before the topical application.

[0038] (19) The method of (18), wherein the topical skin care composition is topically applied to the subject 1 to 3 times daily for 1 to 7 consecutive days.

[0039] (20) A method for adjusting the color saturation of a subject's skin, the method comprising:

[0040] topically applying the topical skin care composition of any one of (1) to (16) to the skin of a subject,

[0041] wherein the topical application increases the saturation C* of the color by at least 10% compared to before the topical application.

[0042] (21) The method of (20), wherein the topical skin care composition is topically applied to the subject 1 to 3 times daily for 1 to 7 consecutive days.

[0043] (22) A collection of topical skin care products for retail sale, the collection comprising:

[0044] (a) a first topical skin care composition comprising:

[0045] (A) about 0.1 to 30 weight % of a reducing sugar relative to the total weight of the topical skin care composition;

[0046] (B) an alkali metal aromatic sulfonate; and

[0047] (C) a carrier,

[0048] The topological polar surface area (tPSA) of the alkali metal aromatic sulfonate (B) is less than and

[0049] wherein the weight ratio of the alkali metal aromatic sulfonate (B) to the reducing sugar (A) ((B):(A)) is 1:20 to 20:1, and

[0050] (b) a second topical skin care composition comprising:

[0051] (A) about 0.1 to 30 weight % of a reducing sugar relative to the total weight of the topical skin care composition;

[0052] (B) an alkali metal aromatic sulfonate; and

[0053] (C) a carrier,

[0054] The topological polar surface area (tPSA) of the alkali metal aromatic sulfonate (B) is less than and

[0055] wherein the weight ratio of the alkali metal aromatic sulfonate (B) to the reducing sugar (A) ((B):(A)) is 1:20 to 20:1, and

[0056] wherein the amount of reducing sugar (A) present in the first topical skin care composition (a) is less than the amount of reducing sugar (A) present in the second topical skin care composition (b), and wherein the amounts are relative to the total weight of the first and second topical skin care compositions, respectively.

[0057] (23) The collection of (22), wherein the first topical skin care composition (a) and the second topical skin care composition (b) are packaged separately.

[0058] (24) A topical skin care composition comprising:

[0059] (A) about 0.1 to 30 weight % of a reducing sugar relative to the total weight of the topical skin care composition;

[0060] (B) an alkali metal aromatic sulfonate; and

[0061] (C) a carrier,

[0062] The topological polar surface area (tPSA) of the alkali metal aromatic sulfonate (B) is less than

[0063] wherein the reducing sugar (A) is dihydroxyacetone, erythrulose or both,

[0064] wherein the alkali metal aromatic sulfonate (B) is an optionally substituted phenylsulfonate, an optionally substituted naphthylsulfonate, or both,

[0065] wherein the carrier (C) comprises an aromatic alcohol, and

[0066] The weight ratio of the alkali metal aromatic sulfonate (B) to the reducing sugar (A) ((B):(A)) is 1:20 to 20:1.

[0067] (25) The topical skin care composition as described in (24), further comprising (D) an organic solvent.

[0068] (26) A topical skin care composition as described in (24), wherein the weight ratio of the alkali metal aromatic sulfonate (B) to the carrier (C) ((B):(C)) is 1:4 to 4:1.

[0069] (27) The topical skin care composition as described in (24), which is substantially free of cationic copolymers.

[0070] (28) A topical skin care composition comprising:

[0071] (A) about 0.1 to 10 weight percent of a reducing sugar relative to the total weight of the topical skin care composition;

[0072] (B) about 0.1 to 10 weight percent of an alkali metal aromatic sulfonate, relative to the total weight of the topical skin care composition; and

[0073] (C) about 0.1 to 5 weight percent of a carrier relative to the total weight of the topical skin care composition,

[0074] The topological polar surface area (tPSA) of the alkali metal aromatic sulfonate (B) is less than

[0075] wherein the reducing sugar (A) is dihydroxyacetone, erythrulose or both,

[0076] wherein the alkali metal aromatic sulfonate (B) is an optionally substituted phenylsulfonate, an optionally substituted naphthylsulfonate, or both,

[0077] wherein the carrier (C) comprises an aromatic alcohol,

[0078] The weight ratio of the alkali metal aromatic sulfonate (B) to the reducing sugar (A) ((B):(A)) is 1:5 to 5:1.

[0079] (29) The topical skin care composition as described in (28), further comprising (D) an organic solvent.

[0080] (30) A topical skin care composition as described in (28), wherein the weight ratio of the alkali metal aromatic sulfonate (B) to the carrier (C) ((B):(C)) is 1:4 to 4:1.

[0081] (31) The topical skin care composition as described in (28), which is substantially free of cationic copolymers.

[0082] The above paragraphs are provided as a summary and are not intended to limit the scope of the appended claims.The described embodiments and their advantages will be better understood by reference to the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0083] This patent or application file contains at least one drawing executed in color. Copies of this patent or patent application publication with color drawing(s) will be provided by the Office upon request and payment of the necessary fee.

[0084] The present disclosure and its many corresponding advantages will be better understood, so that a full appreciation thereof may be readily obtained, by reference to the following detailed description when considered in conjunction with the accompanying drawings, in which:

[0085] Figure 1A The bar graph shows the change in skin darkness (ΔL*) after four applications (once a day for four days) of a control gel having 2 wt% dihydroxyacetone (DHA) alone ("Control") and a prototype gel containing 2 wt% DHA, 2.5 wt% sodium 2-naphthalenesulfonate (NSA) and 2.5 wt% benzyl alcohol (BA) ("Prototype"), respectively.

[0086] Figure 1B The bar graph shows the change in skin hue angle (Δh°) after 4 applications (once a day for 4 days) of a control gel with 2 wt% DHA ("Control") and a prototype gel containing 2 wt% DHA, 2.5 wt% NSA and 2.5 wt% BA ("Prototype"), respectively.

[0087] Figure 1C The pictures show human skin after 4 applications (once a day for 4 days) of a control gel having 2 wt % of dihydroxyacetone (DHA) alone.

[0088] Figure 1D The pictures show human skin after four applications (once a day for four days) of a prototype gel containing 2 wt% DHA, 2.5 wt% sodium 2-naphthalenesulfonate (NSA) and 2.5 wt% benzyl alcohol (BA).

[0089] Figure 2 The bar graphs show the change in skin tone depth 6 hours and 24 hours after application of a control composition having DHA alone ("A"), a topical skin care composition containing DHA and NSA ("B"), and a topical skin care composition containing DHA and sodium p-toluenesulfonate (pTS) ("C"), respectively.

[0090] Figure 3are color-calibrated images showing human skin after treatment with a control composition having DHA alone ("Control") (upper right circles), after treatment with a topical skin care composition containing DHA and NSA ("NSA") (upper left circles), and after treatment with a topical skin care composition containing DHA and pTS ("pTS") (lower left circles), where color calibration was performed using the CASMATCH method (Bear Medic Co.).

[0091] Figure 4 The bar graphs show changes in skin color depth (ΔL*) after 3-times daily application (once per day for 3 consecutive days) and 7-times daily application (once per day for 7 consecutive days) of a control composition ("A") having DHA alone and a topical skin care composition ("B") containing DHA, NSA and BA, as well as after 3-day regression after 7-times daily application.

[0092] Figure 5 The bar graphs show changes in skin hue angle (Δh°) after 3-times daily application (once per day for 3 consecutive days) and 7-times daily application (once per day for 7 consecutive days) of a control composition ("A") having DHA alone and a topical skin care composition ("B") containing DHA, NSA and BA, as well as after 3 days of fading after 7-times daily application, respectively.

[0093] Figure 6 Schematic diagram showing the preparation process for protein solid gel model studies.

[0094] Figure 7A The picture shows the protein solid gel after treatment with DHA alone.

[0095] Figure 7B The picture shows a protein solid gel 24 hours after treatment with a mixture of DHA and pTS.

[0096] Figure 7C The picture shows a protein solid gel 24 hours after treatment with a mixture of DHA and NSA.

[0097] Figure 7D The bar graphs show the change in darkness of protein solid gels 24 hours after treatment with DHA alone ("control"), a mixture of DHA and NSA ("NSA"), and a mixture of DHA and pTS ("pTS"), respectively.

[0098] Figure 8A The picture shows a protein solid gel 7 hours after administration of DHA alone at a temperature of 40°C and a pH of 5.4.

[0099] Figure 8B The picture shows a protein solid gel 7 hours after application of a mixture of DHA and NSA at a temperature of 40°C and a pH of 5.4.

[0100] Figure 8C The picture shows a protein solid gel 7 hours after application of a mixture of DHA and pTS at a temperature of 40°C and a pH of 5.4.

[0101] Figure 8D The picture shows a protein solid gel 7 hours after application of a mixture of DHA and sodium 4-isopropylbenzenesulfonate at a temperature of 40°C and a pH of 5.4.

[0102] Figure 8E The picture shows a protein solid gel 7 hours after application of a mixture of DHA and poly (sodium 4-styrene sulfonate) at a temperature of 40°C and a pH of 5.4.

[0103] Figure 9 It is part of the chromaticity diagram depicted by the CIE L*C*h° and CIE L*a*b* color space models. DETAILED DESCRIPTION

[0104] In the following description, it is to be understood that other embodiments may be utilized and structural and operational changes may be made without departing from the scope of the present embodiments disclosed herein.

[0105] definition

[0106] As used herein, the terms "a," "an," and the like carry the meaning of "one or more."

[0107] In the description of the present disclosure, when expressing a numerical limitation or a numerical range, the endpoints are included. In addition, all values and sub-ranges within the numerical limitation or numerical range are specifically included as if explicitly written.

[0108] When referring to a topical skin care composition, unless otherwise indicated, the phrase "substantially free" describes that the particular component is present in the topical skin care composition in an amount less than about 1 wt %, preferably less than about 0.5 wt %, more preferably less than about 0.1 wt %, even more preferably less than about 0.05 wt %, and even more preferably 0 wt %, relative to the total weight of the topical skin care composition.

[0109] As used herein, when describing quantities and / or positions, the word "about" may be used to indicate that the value and / or position described is within a reasonably expected range of the value and / or position. For example, a value may have the following values: + / - 0.1% of a specified value (or range of values), + / - 1% of a specified value (or range of values), + / - 2% of a specified value (or range of values), + / - 5% of a specified value (or range of values), or + / - 10% of a specified value (or range of values).

[0110] As used herein, the term "optional" or "optionally" means that the subsequently described event may or may not occur, or the subsequently described component may or may not be present (eg, 0 wt %).

[0111] As used herein, the term "substituted" means that at least one hydrogen atom is replaced with a non-hydrogen group, provided that normal valence is maintained and the resulting compound is stable.

[0112] As used herein, unless otherwise indicated, the term "alkyl" refers to a straight chain, branched chain or cyclic aliphatic moiety having at least 1, preferably at least 2, preferably at least 3, preferably at least 4 carbon atoms and up to 22, preferably up to 20, preferably up to 18, preferably up to 12, preferably up to 8 carbon atoms. Examples of alkyl groups include, but are not limited to, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, pentyl, isopentyl, neopentyl, hexyl, isohexyl, 3-methylpentyl, 2,2-dimethylbutyl, 2,3-dimethylbutyl, lauryl, myristyl, cetyl, stearyl, etc., including Guerbet-type alkyl groups (e.g., 2-methylpentyl, 2-ethylhexyl, 2-propylheptyl, 2-butyloctyl, 2-pentylnonyl, 2-hexyldecyl, 2-heptylundecyl, 2-octyldodecyl, 2-nonyltridecyl, 2-decyltetradecyl, and 2-undecylpentadecyl). Cycloalkyl is a type of cyclized alkyl group. Exemplary cycloalkyl groups include, but are not limited to, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, norbornyl, and adamantyl.

[0113] As used herein, the term "aryl" refers to an aromatic group containing only carbon in the aromatic ring, such as phenyl, biphenyl, naphthyl, anthracenyl, etc. Exemplary aryl groups include, but are not limited to, phenyl, 4-methylphenyl (p-tolyl), 2-methylphenyl, 3-methylphenyl, 4-isopropylphenyl, 2-isopropylphenyl, 3-isopropylphenyl, 4-dodecylphenyl, 4-vinylphenyl, 1-naphthyl, and 2-naphthyl.

[0114] As used herein, the term "heteroaryl" refers to an aryl group in which at least one carbon atom is replaced by a heteroatom (e.g., nitrogen, oxygen, sulfur), and can be, for example, indolyl, furyl, imidazolyl, triazolyl, triazinyl, oxazolyl, isoxazolyl, thiazolyl, isothiazolyl, pyrazolyl, pyrrolyl, pyrazinyl, tetrazolyl, pyridinyl (or its N-oxide), thienyl, pyrimidinyl (or its N-oxide), 1H-indolyl, isoquinolinyl (or its N-oxide), or quinolinyl (or its N-oxide).

[0115] As used herein, the term "alkoxy" refers to a straight or branched chain alkyl group to which an oxygen atom is attached. Exemplary alkoxy groups include, but are not limited to, methoxy, ethoxy, propoxy, isopropoxy, butoxy, isobutoxy, sec-butoxy, tert-butoxy, pentyloxy, isopentyloxy, hexyloxy, heptyloxy, octyloxy, nonyloxy, and decyloxy.

[0116] As used herein, the term "alkoxycarbonyl" refers to an alkoxy group bound to a carbonyl group (ie, >C=O).

[0117] As used herein, the term "halogen" refers to fluorine, chlorine, bromine, and iodine.

[0118] As used herein, the term "skin" refers to the skin found in humans and other mammals. It should be recognized that skin is found in many different parts of the body, and application of the topical skin care compositions of the present invention is not limited to skin found on a particular body part. For example, the topical skin care compositions can be applied to any area of skin intended for self-tanning, including the face, extremities, feet, neck, torso, etc. In addition, the topical skin care compositions can be applied to the entire body as a moisturizer in daily skin care routine.

[0119] Various topical skin care composition ingredients are listed in this disclosure and categorized according to their primary or most desired function, benefit, or use. However, categorizing an ingredient according to a particular function, benefit, or use does not necessarily limit the ingredient to that function, benefit, or use. For example, listing benzyl alcohol as a carrier does not limit the usefulness of benzyl alcohol to that of a carrier, as benzyl alcohol may also impart other beneficial properties, such as acting as a preservative and / or a fragrance.

[0120] Topical skin care compositions

[0121] The present disclosure relates to a self-tanning topical skin care composition that adjusts hue angle, reduces brightness, and increases color saturation of skin appearance. The topical skin care composition is easy to apply and can be used to deepen skin color, transform skin tone, and provide even, long-lasting (fade-resistant) tanning coverage.

[0122] Thus, topical skin care compositions contain components that enable skin tanning and components that facilitate the delivery of the tanning agent and make the topical skin care composition easier to apply, thereby reducing the lightness of the skin and changing the skin's tone. Such compositions typically include the following components: a tanning agent, preferably (A) a reducing sugar, (B) an aromatic sulfonate, (C) a carrier, optionally, (D) an organic solvent, (E) water, (F) a thickener, (G) a preservative, and (H) an acidulant. In a preferred embodiment, all components are compatible with the reducing sugar (i.e., do not react with or cause the reducing sugar to react) and are uniformly dispersed or uniformly dissolved in the topical skin care composition. It has now been surprisingly discovered that adding components such as an aromatic sulfonate (B) and a carrier (C) to the reducing sugar (A) enhances the self-tanning effect of the composition, for example, inducing a change in the skin hue angle (h°) in addition to reducing the lightness (L*) of the skin.

[0123] The topical skin care composition can be a liquid, solution, emulsion, lotion, cream, gel, paste, spray, foam or any other form suitable for topical application to the skin. Preferably, the topical skin care composition is in the form of an emulsion, cream, gel, spray or foam. More preferably, the topical skin care composition is in the form of a cream or gel, which can be applied evenly.

[0124] Tanning agent

[0125] In order to function as an effective self-tanner, the topical skin care compositions herein include a "tanning agent," which is any coloring molecule capable of coloring the skin upon contact with the skin, or any non-coloring molecule capable of reacting with the skin and coloring the skin, and in particular, a molecule capable of darkening the skin so as to resemble the tanning effect achieved by exposing human skin to sunlight (i.e., natural tanning).

[0126] In a preferred embodiment, the tanning agent is (A) a reducing sugar. Certain reducing sugars, such as monosaccharides (e.g., dihydroxyacetone), react with naturally occurring amino acids on the skin surface to form pigmented melanoidins via the Maillard reaction, which cause skin discoloration (Bobin et al. J. Soc. Cosmet. Chem., 35, pages 265-272, 1984; Maillard LC, CR Acad. Sci. 154, 66-68, 1912, each of which is incorporated herein by reference in its entirety).

[0127] Different amino acids react differently with different reducing sugars, producing a variety of shades from yellow to brown. Any reducing sugar that reacts with amino acids found in the skin (e.g., naturally occurring amino acids) to darken the skin can be used as a tanning agent. The reducing sugar (A) can be a monosaccharide, which is an aldose having 2 to 6 carbon atoms, preferably 3 to 5 carbon atoms, more preferably 3 to 4 carbon atoms, and even more preferably 3 carbon atoms, or a ketose having 3 to 6 carbon atoms, preferably 4 to 5 carbon atoms, and more preferably 3 to 4 carbon atoms, including mixtures of these aldoses and / or ketoses. Exemplary reducing sugars include, but are not limited to, dihydroxyacetone (DHA), erythrulose, glycolaldehyde, glyceraldehyde, meso-tartaric aldehyde, glucose, gulose, xylose, fructose, ribose, arabinose, allose, talose, altrose, idose, mannose, galactose, and erythrose. In a preferred embodiment, the reducing sugar (A) is dihydroxyacetone, erythrose or both. Most preferably, the reducing sugar (A) is dihydroxyacetone. For example, dihydroxyacetone can be obtained from EMD Millipore.

[0128] The amount of tanning agent present in the topical skin care composition can vary depending on the desired skin color (e.g., lightness, hue angle, color saturation) and the number and nature of the other components. In some embodiments, the tanning agent is present in an amount of at least about 0.05 wt%, preferably at least about 0.1 wt%, preferably at least about 0.5 wt%, preferably at least about 1 wt%, more preferably at least about 1.5 wt%, even more preferably at least about 1.75 wt%, even more preferably at least about 2 wt%, and up to about 10 wt%, preferably up to about 8 wt%, preferably up to about 6 wt%, preferably up to about 4 wt%, preferably up to about 3.5 wt%, more preferably up to about 3 wt%, even more preferably up to about 2.5 wt%, even more preferably up to about 2.25 wt%, based on the total weight of the topical skin care composition.

[0129] In a preferred embodiment, the topical skin care composition is substantially free of tanning agents other than reducing sugars, including being substantially free, preferably completely free (i.e., 0% by weight) of color-providing synthetic dyes and natural pigments. Alternatively, the topical skin care composition may include other tanning agents, such as synthetic dyes and / or natural pigments, in the amounts previously listed.

[0130] Examples of synthetic dyes that can be added as tanning agents include, but are not limited to, acid dyes (e.g., Yellow No. 203 (D&C Yellow No. 10, Color Index (CI) is CI 47005), Orange No. 205 (D&C Orange No. 4, CI 15510), Red No. 3 (Erythrosine B, CI 45430), Red No. 94 (Rose Bengal, CI 45440), and Red No. 227 (D&C Red No.33, CI 17200)); quinone dyes (e.g., anthraquinone, 1N-methylmorpholiniumpropylamino-4-hydroxyanthraquinone, 1-aminopropylamino-4-methylaminoanthraquinone, 1-aminopropylaminoanthraquinone, 5-β-hydroxyethyl-1,4-diaminoanthraquinone, 2-aminoethylaminoanthraquinone, 1,4-bis(β,γ-dihydroxypropylamino)anthraquinone, lawsone, juglone, alizarin, purpurin, carminic acid, carmine, kermesic acid, spinulosin, Disperse Red 1 5, Solvent Violet 13, Disperse Violet 1, Disperse Violet 4, Disperse Blue 1, Disperse Violet 8, Disperse Blue 3, Disperse Red 11, DisperseBlue 7, Basic Blue 22, Disperse Violet 15, Basic Blue 99); azo dyes (e.g., 1,3-dimethyl-2-[[4-(dimethylamino)phenyl]azo]-1H-imidazolium chloride, 1,3-dimethyl-2-[(4-aminophenyl]azo]-1H-imidazolium chloride, 1-methyl-4-[(methylphenylhydrazono)methyl]pyridinium methylsulfate, Disperse Red 17, Basic Red 22, Basic Red 76, Basic Yellow 57, Basic Brown 16, Basic Brown 17, Disperse Black 9); and indoleamine dyes (e.g., 2-β-hydroxyethylamino-5-[bis(β-4′-hydroxyethyl)amino]anilino-1,4-benzoquinone, 2-β-hydroxyethylamino-5-(2′-methoxy-4′-amino)anilino-1,4-benzoquinone, 3-N-(2′-chloro-4′-hydroxy)phenylacetamido-6-methoxy-1,4-benzoquinoneimine, 3-N-(3′-chloro-4′-methylamino)phenylureido-6-methyl-1,4-benzoquinoneimine, 3-[4′-N-(ethylcarbamoylmethyl)amino]phenylureido-6-methyl-1,4-benzoquinoneimine).

[0131] The topical skin care composition may include natural pigments as tanning agents. Non-limiting examples of natural pigments include caramel, beta-carotene, beetroot extract, blue-green algae, cocoa powder, walnut extract, melanin, and curcumin.

[0132] (B) Aromatic sulfonates

[0133] The topical skin care composition of the present disclosure may include an aromatic sulfonate (B). Preferably, the aromatic sulfonate (B) has the formula (I)

[0134]

[0135] or a solvate thereof, a tautomer thereof, a stereoisomer thereof, or a mixture thereof, wherein (i) R is an optionally substituted aryl group or an optionally substituted heteroaryl group, and (ii) X is a cation selected from a hydrogen ion, an ammonium ion, and an alkali metal ion.

[0136] The term "cation" refers to a positively charged ion, including, but not limited to, hydrogen ions, ammonium ions (i.e., NH4 + ), quaternary ammonium ions (such as tetraethylammonium, tetrabutylammonium), lithium ions, sodium ions, potassium ions and silver ions. Preferably, the aromatic sulfonate (B) is an alkali metal aromatic sulfonate. In a preferred embodiment, X is an alkali metal ion, such as lithium ion, sodium ion and potassium ion. Most preferably, X is a sodium ion.

[0137] Aromatic sulfonate (B) can be optionally substituted phenylsulfonate, optionally substituted naphthylsulfonate or both. In a preferred embodiment, R is an optionally substituted aryl. In some embodiments, R is an optionally substituted phenyl. In some embodiments, R is an optionally substituted naphthyl. R can be an aryl or heteroaryl substituted with at least one substituent, such as an optionally substituted alkyl, alkoxy, alkoxycarbonyl, carboxyl, amino, hydroxyl, sulfhydryl, halogen, cyano and nitro. Alternatively, R can be an unsubstituted aryl or heteroaryl.

[0138] In some embodiments, R is an aryl or heteroaryl substituted by at least one linear, branched or cyclic alkyl group, the alkyl group having at least 1, preferably at least 2, preferably at least 3, preferably at least 4, preferably at least 5 carbon atoms, and having up to 14, preferably up to 12, preferably up to 10, preferably up to 8, preferably up to 6 carbon atoms. In a preferred embodiment, R is an aryl or heteroaryl substituted by at least one linear alkyl group such as methyl, ethyl, n-propyl, n-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, n-decyl and n-dodecyl. In a preferred embodiment, R is substituted by at least one branched alkyl group such as isopropyl, sec-butyl, isobutyl, isobutyl, tert-butyl, isopentyl, neopentyl and isohexyl. Most preferably, R is substituted by methyl or isopropyl.

[0139] Disadvantages of using common reducing sugars (e.g., dihydroxyacetone, erythrulose) alone as tanning agents include insufficient coloration, an undesirable orange undertone, rapid fading, and uneven coverage. It has been unexpectedly discovered that a combination of a reducing sugar (A) (e.g., dihydroxyacetone), an aromatic sulfonate (B), and a carrier (C), as described below, provides an intense, long-lasting artificial tan with an aesthetically pleasing red / bronze hue. Without being bound by theory, it is believed that the aromatic sulfonate (B) in the present invention promotes the advanced Maillard reaction by favoring the polymerization of melanoidins with a higher degree of polymerization and / or conjugation, thereby producing an intensely-colored tan with a hue adjustment and fade resistance.

[0140] Exemplary aromatic sulfonates include, but are not limited to, phenylsulfonates, such as sodium benzenesulfonate, sodium p-toluenesulfonate, sodium cumenesulfonate (i.e., sodium 4-isopropylbenzenesulfonate), sodium 2,3-dimethylbenzenesulfonate, sodium 2,5-dimethylbenzenesulfonate, sodium 2,4,6-trimethylbenzenesulfonate, sodium 4-ethylbenzenesulfonate, sodium 4-propylbenzenesulfonate, sodium 4-tert-butylbenzenesulfonate, sodium 4-chlorobenzenesulfonate, sodium 4-bromobenzenesulfonate, sodium 4-hydroxybenzenesulfonate, sodium dodecylbenzenesulfonate, 3-phenylbenzenesulfonate, sodium 4-propylbenzenesulfonate, sodium 4-tert-butylbenzenesulfonate, sodium 4-chlorobenzenesulfonate, sodium 4-bromobenzenesulfonate, sodium 4-hydroxybenzenesulfonate, sodium dodecylbenzenesulfonate, sodium 3-phenylbenzenesulfonate, sodium 4-propylbenzenesulfonate, sodium 4-tert-butylbenzenesulfonate, sodium 4-chlorobenzenesulfonate, sodium 4-bromobenzenesulfonate, sodium 4-hydroxybenzenesulfonate, sodium 4-do ... Naphthalenesulfonates, for example, sodium 1-naphthalenesulfonate, sodium 2-naphthalenesulfonate, sodium 2-methyl-1-naphthalenesulfonate, sodium 4-methyl-1-naphthalenesulfonate, sodium 2-butyl-1-naphthalenesulfonate, sodium 4-hydroxy-1-naphthalenesulfonate, sodium 4-amino-1-naphthalenesulfonate, sodium 6-hydroxy-2-naphthalenesulfonate and sodium 5-amino-1-naphthalenesulfonate, and mixtures thereof.

[0141] In some embodiments, in addition to the aforementioned aromatic sulfonates, polymers or oligomers containing aromatic sulfonates of formula (I) as repeating units may be used instead or additionally, such as poly(sodium 4-styrene sulfonate), poly(4-polystyrene sulfonic acid) ammonium salt, poly(4-polystyrene sulfonic acid), poly(sodium 2-styrene sulfonate) and sodium polyanetholesulfonate.

[0142] In a preferred embodiment, the aromatic sodium sulfonate (B) is at least one selected from sodium 2-naphthalenesulfonate, sodium p-toluenesulfonate, sodium cumenesulfonate, sodium 4-dodecylbenzenesulfonate and poly(sodium 4-styrenesulfonate), more preferably, at least one selected from sodium 2-naphthalenesulfonate (available from Sugai Chemical), sodium p-toluenesulfonate and sodium cumenesulfonate.

[0143] As used herein, the topological polar surface area (tPSA) of a molecule is defined as the sum of the surface contributions of the polar atoms (e.g., oxygen and nitrogen atoms, and bonded hydrogen atoms) in the molecule. Methods for calculating tPSA are known to those of ordinary skill in the art (see, e.g., Ertl, P., et al., "Fast calculation of molecular polar surface area as a sum of fragment based contributions and its application to the prediction of drug transport properties", J. Med. Chem. 2000, 43, 3714-3717, incorporated herein by reference in its entirety). For example, tPSA can be determined using a desktop computer and commercially available chemical graphics software such as ChemAxon-Marvinview and ChemDraw. Alternatively, tPSA can be found in many chemical databases such as SciFinder.

[0144] The topological polar surface area (tPSA) of the aromatic sulfonate (B) useful in the present disclosure is less than For example, at least about Preferably at least about More preferably, at least about More preferably, at least about and at most about Preferably at most about Preferably at most about Preferably at most about More preferably, at most about More preferably, at most about

[0145] As used herein, a hydrogen bond donor site is a functional group having a hydrogen atom that readily coordinates with an electronegative atom (e.g., oxygen, nitrogen, and sulfur). Exemplary hydrogen bond donor sites include NH functional groups in hydroxyl groups, carboxylic acids, thiols, sulfonic acids, primary amines, secondary amines, and amides. In a preferred embodiment, the aromatic sulfonate (B) has at most 2 hydrogen bond donor sites, preferably at most 1 hydrogen bond donor site, and more preferably 0 hydrogen bond donor sites.

[0146] While not wishing to be bound by theory, aromatic sulfonates (B) having lower tPSA values and / or fewer hydrogen bond donors may have better skin penetration and higher transdermal absorption rates, which are advantageous for self-tanning skin care formulations.

[0147] In some embodiments, the aromatic sulfonate (B) is present in an amount of at least about 0.05 wt%, preferably at least about 0.1 wt%, preferably at least about 0.5 wt%, preferably at least about 1 wt%, more preferably at least about 1.5 wt%, even more preferably at least about 2 wt%, still even more preferably at least about 2.5 wt%, and at most about 10 wt%, preferably at most about 8 wt%, preferably at most about 6 wt%, preferably at most about 5 wt%, preferably at most about 4 wt%, more preferably at most about 3.5 wt%, even more preferably at most about 3 wt%, and even even more preferably at most about 2.75 wt%, based on the total weight of the topical skin care composition.

[0148] (C) Carrier

[0149] The topical skin care compositions of the present disclosure may include a carrier (C), which is a material that facilitates uniform delivery and penetration of the tanning agent (and other components of the topical skin care composition) into the skin, thereby achieving a deeper, richer, and longer-lasting tan.

[0150] Examples of carriers (C) suitable for use in the present invention include, but are not limited to, benzyl alcohol, 2-phenylethanol, phenoxyethanol, methanol, ethanol, n-propanol, isopropanol, n-butanol, sec-butanol, isobutanol, tert-butanol, hexanol, n-octanol, 2-octanol, -2-ethylhexanal, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, and mixtures thereof.

[0151] In some embodiments, the carrier (C) comprises an aromatic alcohol. Due to the presence of a polar end (hydroxyl) and a non-polar end (phenyl), aromatic alcohols (e.g., benzyl alcohol, 2-phenylethanol, phenoxyethanol) can be more effective in transdermal delivery of tanning agents (and other components of the topical skin care composition) than other short-chain alkyl alcohols (e.g., ethanol and n-butanol). In addition, benzyl alcohol is particularly advantageous due to its moderate water solubility, aromatic odor, antibacterial properties, and low toxicity. In a preferred embodiment, the carrier (C) used in the present invention comprises benzyl alcohol, 2-phenylethanol, 1-phenylethanol, phenoxyethanol, or a mixture thereof. Most preferably, the carrier (C) comprises benzyl alcohol, or consists essentially of benzyl alcohol (benzyl alcohol is available from Emerald Kalama Chemical).

[0152] In some embodiments, the amount of carrier (C) present in the topical skin care composition is at least about 0.1 wt%, preferably at least about 0.5 wt%, preferably at least about 1 wt%, preferably at least about 1.5 wt%, preferably at least about 2 wt%, and at most about 5 wt%, preferably at most about 4 wt%, preferably at most about 3 wt%, preferably at most about 2.5 wt%, based on the total weight of the topical skin care composition.

[0153] The weight ratio between the reducing sugar (A) (e.g., dihydroxyacetone), the aromatic sulfonate (B) (e.g., sodium 2-naphthalenesulfonate, sodium p-toluenesulfonate), and the carrier (C) (e.g., benzyl alcohol) can be varied depending on the tanning shade (e.g., darkness, hue angle, color saturation). Typically, however, the weight ratio of aromatic sulfonate (B) to reducing sugar (A) ((B):(A)) is at least 1:20, preferably at least 1:15, preferably at least 1:10, preferably at least 1:8, preferably at least 1:6, preferably at least 1:5, preferably at least 1:4, preferably at least 1:3, more preferably at least 1:2, further more preferably at least 2:3, still further more preferably at least 1:1, and at most 20:1, preferably at most 15:1, preferably at most 10:1, preferably at most 8:1, preferably at most 6:1, preferably at most 5:1, preferably at most 4:1, preferably at most 3:1, more preferably at most 2:1, further more preferably at most 3:2, yet further more preferably at most 5:4.

[0154] In some embodiments, the weight ratio of aromatic sulfonate (B) to carrier (C) ((B):(C)) is at least 1:4, preferably at least 2:7, preferably at least 1:3, preferably at least 2:5, more preferably at least 1:2, further more preferably at least 2:3, yet further more preferably at least 1:1, and at most 4:1, preferably at most 7:2, preferably at most 3:1, preferably at most 5:2, more preferably at most 2:1, further more preferably at most 3:2, yet further more preferably at most 5:4.

[0155] (D) Organic solvents

[0156] The topical skin care composition may optionally include an organic solvent (D) that is structurally different from the carrier (C). The organic solvent (D) may aid in the dissolution of components that are not sufficiently soluble in the aforementioned carrier, adjust the surface properties of the topical skin care composition to enhance processability, viscosity and / or ease of handling, or generally provide a medium suitable for automatic tanning operations. Examples of organic solvents that can be used in the present disclosure include, but are not limited to, polyols such as ethylene glycol, propylene glycol (e.g., 1,3-propylene glycol, 1,2-propylene glycol), butylene glycol (e.g., 1,3-butylene glycol, 1,2-butylene glycol, 1,4-butylene glycol, 2,3-butylene glycol), hexylene glycol, isopentylene glycol, diethylene glycol, dipropylene glycol, glycerol, polyol ethers such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, propylene glycol monomethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether), and C1-C4 lower alkanols such as methanol, ethanol, isopropanol, butanol, and mixtures thereof. In some embodiments, the organic solvent (D) comprises a polyol selected from at least one of 1,3-propylene glycol, 1,2-propylene glycol, ethylene glycol, glycerol and 1,3-butylene glycol (available from OXEA). In a preferred embodiment, the organic solvent (D) is 1,3-propylene glycol.

[0157] Alternatively, a mixture of polyols is used as the organic solvent (D), such as a mixture of a first polyol and a second polyol different from the first polyol. In some embodiments, the first polyol is 1,3-propylene glycol. In some embodiments, the second polyol is glycerol. When a mixture of a first polyol (e.g., 1,3-propylene glycol) and a second polyol (e.g., glycerol) is used, the weight ratio of the first polyol to the second polyol can generally be at least 1:6, preferably at least 1:5, preferably at least 1:4, preferably at least 1:3, more preferably at least 1:2, more preferably at least 1:1, further more preferably from 3:2, further more preferably at least 2:1, and at most 10:1, preferably at most 8:1, preferably at most 6:1, more preferably at most 5:1, further more preferably at most 4:1, further more preferably at most 3:1.

[0158] When present, the organic solvent (D) can be included in the topical skin care composition in an amount ranging from at least about 0.2 wt %, preferably at least about 0.5 wt %, more preferably at least about 1 wt %, more preferably at least about 2 wt %, more preferably at least about 3 wt %, even more preferably at least about 4 wt %, still even more preferably from about 5 wt %, and up to about 20 wt %, preferably up to about 15 wt %, preferably up to about 12 wt %, more preferably up to about 10 wt %, even more preferably up to about 8 wt %, even even more preferably up to about 6 wt %, based on the total weight of the topical skin care composition.

[0159] The weight ratio of carrier (C) (e.g. benzyl alcohol) to organic solvent (D) (e.g. 1,3-propylene glycol, ethylene glycol, glycerol) can range from at least 1:200, preferably at least 1:150, preferably at least 1:100, preferably at least 1:50, preferably at least 1:25, preferably at least 1:20, preferably at least 1:10, more preferably at least 1:8, further more preferably at least 1:6, still further more preferably at least 1:5, and at most 25:1, preferably at most 20:1, preferably at most 15:1, preferably at most 10:1, preferably at most 5:1, preferably at most 3:1, preferably at most 2:1, preferably at most 1:1, more preferably at most 1:2, further more preferably at most 1:3, yet further more preferably at most 1:4.

[0160] (E) Water

[0161] In some embodiments, the topical skin care composition of the present disclosure is an aqueous composition or an oil-in-water (o / w) emulsion in which the continuous phase is aqueous. Therefore, in a preferred embodiment, the topical skin care composition further comprises water (E) in an amount of at least about 10 wt %, preferably at least about 20 wt %, preferably at least about 30 wt %, preferably at least about 40 wt %, more preferably at least about 50 wt %, further more preferably at least about 60 wt %, even further more preferably at least about 70 wt %, and up to about 95 wt %, preferably up to about 90 wt %, more preferably up to about 85 wt %, and even more preferably up to about 80 wt %, based on the total weight of the topical skin care composition.

[0162] (F) Thickener

[0163] The topical skin care composition may optionally include a thickener (F), which may enhance the stability of the composition and provide a consistency that is soothing to the skin upon application.

[0164] Thickener (F) may comprise a copolymer comprising at least one structural unit selected from the group consisting of hydroxyalkyl acrylate, acrylic acid salt, acrylamide, and acryloyldialkyl taurate. Examples of thickening copolymers include copolymers of hydroxyethyl acrylate and sodium acryloyldimethyl taurate, copolymers of acrylic acid ester and sodium acryloyldimethyl taurate, copolymers of acrylamide and acrylic acid ester, and copolymers of acrylic acid, acrylamide, acrylic acid ester, and sodium acryloyldimethyl taurate. Preferably, thickener (F) contains an anionic (co)polymer.

[0165] These thickening copolymers are commercially available, for example, from SEPPIC, France. Exemplary thickeners containing copolymers of hydroxyethyl acrylate and acryloyldimethyl taurate include SEPINOV TM EMT10 (Hydroxyethyl Acrylate / Sodium Acryloyldimethyl Taurate Copolymer), SIMULGEL TM NS (Hydroxyethyl Acrylate / Sodium Acryloyldimethyl Taurate Copolymer, Squalane, Polysorbate 60), SIMULGEL TM FL (Hydroxyethyl Acrylate / Sodium Acryloyldimethyl Taurate Copolymer, Isohexadecane, Polysorbate 60), SEPIPLUS TM S (Hydroxyethyl Acrylate / Sodium Acryloyldimethyl Taurate Copolymer, Polyisobutene, PEG-7 Trimethylolpropane Coconut Ether) and SIMULGEL TM INS100 (hydroxyethyl acrylate / sodium acryloyldimethyl taurate copolymer, isohexadecane, polysorbate 60). Exemplary thickeners containing copolymers of acrylates and acryloyldimethyl taurate include SIMULGEL TMEG (sodium acrylate / sodium acryloyldimethyl taurate copolymer, isohexadecane, polysorbate 80), SIMULGEL TM EPG (sodium acrylate / sodium acryloyldimethyl taurate copolymer, polyisobutene, caprylyl capryl glucoside), and SIMULGEL TM SMS 88 (sodium acrylate / acryloyldimethyltaurate / dimethylacrylamide crosspolymer, isohexadecane, polysorbate 60). Examples of thickeners containing copolymers of acrylamide and acrylate include SEPIPLUS TM 265 (acrylamide / ammonium acrylate copolymer, polyisobutylene, polysorbate 20). Examples of thickeners containing copolymers of acrylic acid, acrylamide, acrylates, and acryloyldimethyl taurate include SEPIPLUS TM 400 (polyacrylate-13, polyisobutylene, polysorbate 20).

[0166] In some embodiments, the thickener (F) comprises a copolymer of hydroxyethyl acrylate and sodium acryloyldimethyl taurate. More preferably, the thickener is SEPIPLUS TM S(Hydroxyethyl Acrylate / Sodium Acryloyldimethyl Taurate Copolymer, Polyisobutene, PEG-7 Trimethylolpropane Coconut Ether).

[0167] In addition to the aforementioned thickening agents, other thickening materials that may be used alternatively or additionally include carbomers (e.g., carbomer 980), C 10-30 Alkyl acrylate crosspolymers (e.g. Pemulen TR-1, Pemulen TR-2 (Acrylates / C 10-30 Alkyl Acrylate Crosspolymer)), SEPIGEL TM 305 (polyacrylamide, C 13-14 Isoparaffin, Laureth-7), SIMULGEL TM A (ammonium polyacrylate, isohexadecane, PEG-40 castor oil), SIMULGEL TM 600 (acrylamide / sodium acryloyldimethyltaurate copolymer, isohexadecane, polysorbate 80), AVC (ammonium acryloyldimethyltaurate / N-vinylpyrrolidone copolymer), AVS (sodium acryloyldimethyltaurate / N-vinylpyrrolidone copolymer) and modified cellulose polymers (eg, hydroxyethylcellulose, methylcellulose).

[0168] As used herein, unless otherwise specified, a cationic copolymer refers to a copolymer comprising a cationic monomer as one of the repeating units, the cationic monomer being methacryloylethyltri(C1-C3 alkyl)ammonium salt or acryloylethyltri(C1-C3 alkyl)ammonium salt (e.g., acryloylethyltrimethylammonium chloride). Exemplary monomers that can be used to form cationic copolymers with methacryloylethyltri(C1-C3 alkyl)ammonium salt or acryloylethyltri(C1-C3 alkyl)ammonium salt include acrylamide, methacrylamide, tris(hydroxymethyl)-acrylamidomethane, and the monomers disclosed in U.S. Pat. No. 7,780,954, which is incorporated herein by reference in its entirety.

[0169] In a preferred embodiment, the topical skin care composition is substantially free of cationic copolymers, including being substantially free, preferably completely free (i.e., 0% by weight), of the aforementioned cationic copolymers, such as acrylamide / acryloylethyltrimethylammonium chloride / tris(hydroxymethyl)-acrylamidomethane copolymer.

[0170] (G) Preservatives

[0171] The topical skin care composition may optionally further include a preservative (G). For example, the preservative may be selected to kill bacteria that may survive or reproduce in the composition, or to prevent degradation or chemical decomposition (such as oxidative degradation) of the composition. Preservatives suitable for cosmetic preparations are well known to those of ordinary skill in the art. In this respect, the preservative selected can vary according to the specific components present in the topical skin care composition. Examples of suitable preservatives include methylparaben, ethylparaben, propylparaben, EDTA or its salts (such as disodium EDTA), phenoxyethanol, DMDM hydantoin, benzyl alcohol, ethyldibromoglutaronitrile-phenoxyethanol / polyquaternium-7 (Euxyl K-400, Calgon), imidazolidinyl urea, diazolidinyl urea, benzalkonium chloride, benzethonium chloride, sodium benzoate, sorbic acid, etc., or a combination thereof.

[0172] Preferably, the preservative (G) is methylparaben and / or ethylparaben, most preferably a mixture of these preservatives. When present, the preservative (G) herein may be included in an amount of up to about 5 wt %, preferably up to about 4 wt %, preferably up to about 3 wt %, preferably up to about 2 wt %, preferably up to about 1 wt %, preferably up to about 0.5 wt %, for example, from about 0.001 wt % to about 3 wt %, or from 0.1 wt % to about 1.5 wt %, or from 0.15 wt % to about 1 wt %, or from 0.3 wt % to about 0.45 wt %, based on the total weight of the topical skin care composition.

[0173] (H) Acidifier

[0174] The topical skin care compositions of the present disclosure may optionally be formulated to include an acidulant (H) for adjusting the pH to a more acidic / less alkaline setting. Additionally, depending on the chemical structure, the acidulant (H) may act as a chelating agent and / or buffer to neutralize minerals, enhance the activity of any preservatives present, and stabilize active ingredients (e.g., tanning agents).

[0175] The acidulant used herein may be an inorganic acid or an organic acid, specifically including, but not limited to, hydrochloric acid, orthophosphoric acid, sulfuric acid, carboxylic acids (e.g., fumaric acid, acetic acid), and α-hydroxy acids (e.g., tartaric acid, citric acid, malic acid, lactic acid, and glycolic acid), and mixtures thereof. When the acidulant contains an α-hydroxy acid functional group, the acidulant may also help exfoliate the skin and soften wrinkles. Preferably, citric acid is used.

[0176] When present, the acidulant (H) can be included herein in an amount of up to about 5 wt %, preferably up to about 4 wt %, preferably up to about 3 wt %, preferably up to about 2 wt %, preferably up to about 1 wt %, for example, from about 0.001 wt % to about 3 wt %, or from 0.02 wt % to about 2 wt %, or from 0.1 wt % to about 1 wt %, or from 0.2 wt % to about 0.5 wt %, based on the total weight of the topical skin care composition. The pH of the topical skin care composition can vary, but is preferably less than 6.5, for example, at least 2, preferably at least 2.5, more preferably at least 3, even more preferably at least 3.5, and at most 6, preferably at most 5, more preferably at most 4.

[0177] Other optional ingredients

[0178] Various optional ingredients commonly used in topical formulations, such as fragrances, propellants, carriers, adjuvants, anti-aging ingredients, proteins, rheology modifiers, dispersants, thickeners, film formers, chelating agents, detergents, vitamins, botanicals, and sunscreens, as well as other types of materials whose presence may be cosmetically, medically, or otherwise desirable, may optionally be included at their usage levels as determined by conventional techniques. For example, the formulations of the topical skin care compositions of the present disclosure may optionally be formulated to include one or more fragrances known to those of ordinary skill in the cosmetic arts to impart a pleasant scent to the topical skin care compositions or to help mask any malodorous components that may be present in the topical skin care compositions.

[0179] In preferred embodiments, the topical skin care compositions are substantially free of such optional ingredients; however, when such ingredients are included, non-limiting examples of materials that may be used include: film-forming materials such as petrolatum, hydrolyzed wheat protein / wheat oligosaccharides (e.g., Cropeptide® from Croda Inc.), W), hydrolyzed corn protein, hydrolyzed wheat gluten, hydrolyzed yeast protein, hydrolyzed vegetable protein, hydrolyzed soy protein, hydrolyzed rice protein, hydrolyzed potato protein; humectants, such as glycereth-7 triacetate (Dermol GL-7-A, Alzo), glycereth-5-lactate, and glycereth-7 diisononanoate; skin conditioning agents and emollients, such as mineral oil, cetearyl alcohol, silicones (e.g., dimethicone, cyclomethicone, phenyl trimethicone, alkyl dimethicone, fluorinated silicones), isononanoates (e.g., ethylhexyl isononanoate, butylene glycol diisononanoate, cetearyl isononanoate, and cetyl isononanoate), and polyethylene glycol derivatives of castor oil, such as PEG-40 castor oil (Surfactol 365, available from Vertellus), PEG-45 castor oil, PEG-50 castor oil, PEG-60 castor oil, and PEG-100 castor oil; surfactants, for example, polyoxyalkylene ethers of fatty alcohols, for example, Laureth-3, Ceteareth-6, Ceteareth-11, Ceteareth-15, Ceteareth-16, Ceteareth-17, Ceteareth-18, Ceteareth-20, Ceteareth-23, Ceteareth-25, Ceteareth-27, Ceteareth-28, Ceteareth-30, Isoceteth-20, Laureth-9 / Myristeth-9, and PPG-3 caprylyl ether, steareths (steareth-2, steareth-4, steareth-6, steareth-7, steareth-10, steareth-11, steareth-13, steareth-15, steareth-20), and polyethylene glycol esters, for example, PEG-14 laurate, PEG-15 laurate, PEG-20 laurate, PEG-32 laurate, PEG-75 laurate, PEG-150 laurate, or other surfactants; and sunscreens or UV light absorbing compounds, for example, octyldimethyl PABA, benzophenone-4, DEA methoxycinnamate, 2-phenyl-benzimidazole-5-sulfonic acid, and triethanolamine salicylate.

[0180] In a preferred embodiment, the topical skin care composition comprises 1-3 wt% of a reducing sugar (A) (e.g., dihydroxyacetone, erythrulose), 1-3 wt% of an aromatic sulfonate (B) (e.g., sodium 2-naphthalenesulfonate, sodium p-toluenesulfonate, or both), 1-3 wt% of a carrier (C) (e.g., benzyl alcohol), 2-8 wt% of an organic solvent (D) (e.g., 1,3-propylene glycol, 1,2-propylene glycol, ethylene glycol, glycerol, 1,3-butylene glycol), and 70-82 wt% of water (E), based on the total weight of the topical skin care composition, respectively. The balance optionally comprises one or more preservatives (G) (e.g., a mixture of methylparaben and ethylparaben), an acidulant (H) (e.g., citric acid), and a thickener (F) (e.g., SEPIPLUS S (hydroxyethyl acrylate / sodium acryloyldimethyl taurate copolymer, polyisobutylene, PEG-7 trimethylolpropane coconut ether)).

[0181] In a preferred embodiment, the topical skin care composition comprises 1-3 wt% of a reducing sugar (A) (e.g., dihydroxyacetone), 1-3 wt% of an aromatic sulfonate (B) (e.g., sodium 2-naphthalenesulfonate, sodium p-toluenesulfonate, or both), 1-3 wt% of a carrier (C) (e.g., benzyl alcohol), 2-8 wt% of an organic solvent (D) (e.g., 1,3-propylene glycol, 1,2-propylene glycol, ethylene glycol, glycerol, 1,3-butylene glycol), 70-82 wt% of water (E), 0.001-1 wt% of a preservative (G) (e.g., a mixture of methylparaben and ethylparaben), 0.001-0.2 wt% of an acidulant (H) (e.g., citric acid), and 1-3 wt% of a thickener (F) (e.g., SEPIPLUS). TM S(Hydroxyethyl Acrylate / Sodium Acryloyldimethyl Taurate Copolymer, Polyisobutene, PEG-7 Trimethylolpropane Coconut Ether)).

[0182] The topical skin care composition of the present invention can be prepared by any method known to those skilled in the art. For example, an aqueous topical skin care composition can be prepared by the following method: (i) in a container of appropriate size, all water-soluble components except the tanning agent (e.g., reducing sugar) are mixed with water, optionally heated (e.g., 40-90° C., preferably 50-85° C., more preferably 75-81° C.), and stirred until homogeneous, (ii) in a separate container, all oil phase ingredients (if any) are mixed, optionally heated (e.g., 40-90° C., preferably 50-85° C., more preferably 75-81° C.), and stirred until homogeneous, (iii) The homogenous mixture from (i) is mixed with the homogenous mixture from (ii) (if any), optionally heated (e.g., 40-90° C., preferably 50-85° C., more preferably 75-81° C.), and stirred until a homogenous aqueous composition or a homogenous oil-in-water emulsion is formed, (iv) the homogenous aqueous composition or the homogenous oil-in-water emulsion is cooled, and (v) upon cooling, a tanning agent (e.g., a reducing sugar) is added to the homogenous aqueous composition or the homogenous oil-in-water emulsion, optionally with stirring under similar conditions as described above, thereby forming a topical skin care composition. If present, a thickener may be added during step (i), or after step (iii) and before the addition of the tanning agent (i.e., before step (v)). Once cooling is complete, the resulting topical skin care composition may be packaged in the desired packaging. Agitation may be provided by a propeller (e.g., a high shear mixer and a high-speed dissolver).

[0183] Automatic tanning method

[0184] In one or more embodiments, the present disclosure provides methods of regulating skin color by topically applying a topical skin care composition to the skin of a subject.

[0185] To achieve an acceptable degree of coloration or tanning, a person desiring such coloration or tanning can apply an effective amount of the topical skin care composition evenly to the desired body surface area over an effective application time. Thus, the topical skin care composition can be used to provide a subtle change in skin color or a more pronounced tanning effect. Furthermore, the methods disclosed herein can produce a rich, dark, aesthetically pleasing, and long-lasting tan on the skin by simultaneously adjusting the hue angle and increasing the saturation and depth of the skin tone.

[0186] The topical skin care composition can be applied topically to wet or dry (dyed) skin. Preferably, the desired skin area is cleansed and / or exfoliated prior to application. During application, the topical skin care composition can be applied directly to the external skin using, for example, the hands, an applicator (e.g., a paper towel, a puff, a roller, or a sprayer). The topical skin care composition can be used as a single treatment to color the skin, or it can be applied in a gradual manner so that the tan of the skin becomes more intense in subsequent applications until the desired degree of coloration is achieved.

[0187] The topical skin care composition can be applied to the desired area as needed, preferably 1 to 4 times per day, more preferably 2 to 3 times per day. Application can be carried out for at least 1 day, preferably at least 2 consecutive days, more preferably at least 3 consecutive days, even more preferably at least 4 consecutive days, and up to 14 consecutive days, preferably up to 7 consecutive days, more preferably up to 6 consecutive days, even more preferably up to 5 consecutive days. Alternatively, application can be carried out intermittently. If desired, application times outside these ranges can be used to vary the degree of coloration.

[0188] The appearance of a color, such as the color of skin, can be expressed in terms of its hue (color), brightness (brightness), and saturation (vividness). Hue is the primary attribute of color perception and is used to represent "unique shades" (e.g., red, yellow, blue), which are perceived as distinct hues. Saturation (also called chroma or visual color) refers to the "purity" of a particular hue. Highly saturated hues have vivid, intense colors, while less saturated hues appear more muted and dull. Without saturation, the hue becomes grayscale. Brightness indicates the perceived brightness or depth of a color. For example, the brighter the image, the greater the amount of light reflected.

[0189] The quantification of these color attributes (hue, saturation, brightness) can be performed using various color models, including the CIE (International Commission on Illumination) L*a*b* (CIELAB) color space model, the CIE L*C*h° (CIEHCL) color space model, the CIE XYZ model, the RGB color model, and the like.

[0190] In some embodiments, skin color in the present invention is measured using the CIE L*a*b* model, where (i) L* represents the lightness of a color, with a value ranging from 0 (black) to 100 (white), (ii) a* represents the red / green value of a color, and (iii) b* represents the yellow / blue value of a color. In some embodiments, skin color in the present invention is measured using the CIE L*C*h* model. oModel measurement, where (i) L* represents the lightness of the color, which is the same as the L* of the CIE L*a*b* model, (ii) C* represents the saturation (chroma), with values ranging from 0 (no saturation) to 60 (full saturation), and (iii) h o Indicates the hue angle. As shown in the chromaticity diagram ( Figure 9 ), the hue angle of skin color in the present invention is expressed in degrees and originates from the +a* axis. Specifically, a hue angle of 0° is red (+a*), and a hue angle of 90° is yellow (+b*). The color properties of skin in the present invention can be measured using a spectrophotometer, such as the CM-700d, CM-2500d, or CM-2600d spectrophotometers manufactured by Konica Minolta.

[0191] The methods of the present invention can transform the skin's color tone after application of a topical skin care composition. In some embodiments, the methods of the present invention can transform the skin's color tone after application of a topical skin care composition. o Decrease or increase by at least about 0.1°, preferably at least about 0.2°, preferably at least about 0.3°, preferably at least about 0.4°, more preferably at least about 0.5°, further more preferably at least about 0.6°, even further more preferably at least about 0.7°, and at most about 2°, preferably at most about 1.5°, preferably at most about 1.2°, more preferably at most about 1°, even more preferably at most about 0.8°.

[0192] Preferably, the method of the invention reduces the hue angle h of the skin color compared to before topical application. o The decrease is, for example, at least about 0.2°, preferably at least about 0.3°, preferably at least about 0.4°, more preferably at least about 0.5°, further more preferably at least about 0.6°, still further more preferably at least about 0.7°, and at most about 1.5°, preferably at most about 1.2°, more preferably at most about 1°, and still more preferably at most about 0.8° (see Figure 5 A reduction in the hue angle of treated skin generally indicates that the topical skin care composition produces a bronze or red hue when applied to the skin.

[0193] The methods of the present invention can darken skin color after application of the topical skin care composition. In some embodiments, the methods of the present invention reduce the lightness L* of skin color by at least about 1%, preferably at least about 2%, preferably at least about 3%, preferably at least about 4%, more preferably at least about 5%, even more preferably at least about 6%, even more preferably at least about 7%, and at most about 20%, preferably at most about 15%, preferably at most about 12%, more preferably at most about 10%, even more preferably at most about 8%, compared to before topical application.

[0194] In a preferred embodiment, the method of the present invention simultaneously changes the hue angle of the treated skin and reduces the brightness according to the above-specified ranges.

[0195] Notably, the combination of a reducing sugar (A) (e.g., dihydroxyacetone, erythrulose), an aromatic sulfonate (B) (e.g., sodium 2-naphthalenesulfonate, sodium p-toluenesulfonate), and a carrier (C) (e.g., benzyl alcohol) produced unexpected tanning results (darker, longer-lasting (i.e., more resistant to fading), more aesthetically pleasing coloration) compared to the use of reducing sugars alone.

[0196] For example, Figure 5 As shown, the use of reducing sugars alone does not significantly reduce the hue angle of treated skin and, in some cases, actually increases the hue angle after prolonged application (e.g., after 7 days of application). However, combining the aromatic sulfonate (B) and carrier (C) with the reducing sugar (A) significantly reduces the hue angle, thereby imparting an aesthetically pleasing red / bronze hue to the treated skin. Figure 4 As shown, the use of reducing sugar alone results in at least 30% less reduction in skin brightness, preferably at least 35% less, more preferably at least 40% less, even more preferably 45% less, and up to 70% more, preferably up to 60% more, and more preferably up to 50% less, than the use of a combination of reducing sugar (A), aromatic sulfonate (B), and carrier (C). In addition, the artificial tan produced by this combination fades significantly slower than the use of reducing sugar alone (e.g., less than about 40% fading vs. at least 80% fading after 3 days of regression).

[0197] The methods of the present invention can be used to adjust the color saturation of the skin. In some embodiments, the methods of the present invention increase the saturation C* of the color of the treated skin by at least about 1%, preferably at least about 2%, preferably at least about 3%, preferably at least about 4%, more preferably at least about 5%, even more preferably at least about 6%, even more preferably at least about 7%, and at most about 20%, preferably at most about 15%, preferably at most about 12%, more preferably at most about 10%, and even more preferably at most about 8%, compared to before topical application.

[0198] The following examples are intended to further illustrate the topical skin care compositions and are not intended to limit the scope of the claims.

[0199] Example

[0200] Topical skin care compositions

[0201] Examples 1-3 below provide several exemplary topical skin care compositions, including comparative compositions, for evaluation of tanning performance. The amounts of each component are expressed as weight percent relative to the total weight of 100%. DHA refers to dihydroxyacetone, available from EMD Millipore. NSA refers to sodium 2-naphthalenesulfonate, available from Sugai Chemical. pTS refers to sodium p-toluenesulfonate. BA refers to benzyl alcohol, available from Kalama. 1,3-Butanediol, methylparaben, ethylparaben, and SEPIPLUS TM S was obtained from Oxea, Ueno, Sharon, and Seppic, respectively. PD refers to propylene glycol. GLY refers to glycerol. * in the following tables indicates that the example is a comparative example.

[0202] Example 1

[0203] Table 1 Exemplary topical skin care compositions

[0204] INCI = International Nomenclature of Cosmetic Ingredients

[0205]

[0206]

[0207]

[0208]

[0209] Preparation method

[0210] An exemplary method for preparing an exemplary topical skin care composition is as follows:

[0211] Part A: First, add deionized water and 1,3-butanediol to the main container and mix thoroughly. Heat the main container to a temperature of 75-81°C. When the main container temperature reaches 75°C, add parabens, BA, and NSA to the main container and mix until clear. Then turn off the heater. Add SEPIPLUS TM S is added to the main container and mixed for about 20 minutes. TM After the mixture thickens, stirring can be increased. The main container is cooled to below 40°C to form Part A.

[0212] Part B: Add deionized water and DHA to a separate container and mix until clear to form Part B.

[0213] After cooling Part A to a temperature below 40°C, add Part B to Part A to form Part AB, which is mixed for about 5 minutes.

[0214] Finally, citric acid is added to part AB to adjust the pH to 3.5-4.0, thereby forming a topical skin care composition.

[0215] Topical skin care composition evaluation method

[0216] (1) Skin test

[0217] The example composition was injected at 2 mg / cm 2 The amount of the test product was applied to the skin. Before application and at different time points after application of the test product specified in each test, the color parameters of the skin (e.g., lightness L*, hue angle h°) were measured, and then the changes in each parameter compared to before application (ΔL*, Δh°) were calculated. Specifically, a CM-2600d manufactured by Konica Minolta, Inc. was used as a spectrophotometer.

[0218] Skin testing can be performed as a consumer home-use study. For example, Figure 4 and Figure 5 Data were collected using the following method. Consumers applied a lotion containing either DHA alone ("Control DHA") or DHA, NSA, and BA ("+NSA / BA") to their arms and legs once daily for 7 days. Color measurements were taken on the arms and legs at baseline (Day 0), on Day 3, and on Day 7. Starting on Day 7, the test group members stopped using the test product. Additional color measurements were taken on the arms and legs on Day 10.

[0219] (2) Protein solid gel model test

[0220] Protein solid gel sample preparation:

[0221] Equipment: Digital balance (accurate to 0.01 g), 600 mL beaker, three 300 mL beakers, large water bath, two stainless steel insulators to fit 300 mL flasks, two microspatulas or tongue depressors, 36 Falcon Petri dishes with lids, and pipettes.

[0222] Materials: Deionized water (DI water), Gelatin A (Gel A) stored on the bench at room temperature, Bovine serum albumin (BSA) (stored in a laboratory refrigerator at 5°C).

[0223] Preparation of Gelatin A Premix:

[0224] (i) Obtain the tare weight of the 600 mL beaker + microspatula / tongue depressor;

[0225] (ii) Add 40 g of gel A to the beaker;

[0226] (iii) Add DI water to the beaker to make a total solution of 200 g;

[0227] (iv) placing the beaker with the solution in a water bath;

[0228] (v) Set the water bath temperature to 60°C;

[0229] (vi) Frequently stir the solution in the beaker slowly using a microspatula / tongue depressor to prevent film formation on the surface of the solution;

[0230] (vii) Mix the solution until homogeneous, which may take 1 hour.

[0231] Preparation of BSA premix:

[0232] (i) Obtain the tare weight of the 300 mL beaker + microspatula / tongue depressor;

[0233] (ii) Add 8 g of BSA to the beaker;

[0234] (iii) Add DI water to the beaker to make a total solution of 200 g;

[0235] (iv) stirring the solution slowly using a microspatula / tongue depressor;

[0236] (v) Stir the solution until homogeneous, which may take 1 hour (do not heat, as BSA degrades at higher temperatures); and

[0237] (vi) Place the remaining two empty 300 mL beakers into a stainless steel insulator and place it in the water bath. If necessary, use weighted rods to hold the beakers in place.

[0238] Prepare the Petri dish:

[0239] (i) Weigh each Petri dish without its lid and record the weight on the side of the dish;

[0240] (ii) Arrange the dishes in order of increasing weight;

[0241] (iii) For a group, label the sides of each petri dish with the same letter and increase by integers, such as Y01, Y02, Y03...Y10, Y11, etc.

[0242] Combination of premixes:

[0243] (i) Once the Gel A and BSA premixes are clear and free of aeration (each premixed with DI water to give a 200 g total solution, see above), stir the Gel A and BSA premixes separately for 2-3 minutes;

[0244] (ii) adding the BSA premix to the Gel A premix by slowly pouring the BSA premix along the inner wall of the beaker containing the Gel A premix, thereby forming a combined protein solution;

[0245] (iii) slowly stirring the combined protein solution for 2 minutes;

[0246] (iv) remove the insulation from the water bath and wipe the outside of the two 300 mL beakers (described in part E of step (vi)) dry with a towel; and

[0247] (v) Add the combined protein solution to two insulated 300 mL beakers by slowly pouring equal amounts of solution down the inside wall of each beaker.

[0248] Preparation of gel slabs:

[0249] Use a pipette to add the desired amount of the combined protein solution to the culture dish. The dish containing the solution is then dried on the bench to form a gel slab.

[0250] Color measurement of protein solid gel:

[0251] Color measurements were performed using image analysis provided by the software ImageJ.

[0252] Whether explicitly recited or not, the present disclosure also contemplates other embodiments "comprising," "consisting of," and "consisting essentially of" the embodiments or elements described herein.

[0253] Obviously, the present invention is susceptible to numerous modifications and variations in light of the above teachings, and it should therefore be understood that within the scope of the appended claims, the present invention may be practiced otherwise than as specifically described herein.

[0254] All patents and other references mentioned above are hereby incorporated by reference in their entirety as if fully set forth.

Claims

1. A topical skin care composition comprising: (A) 0.1 to 30 wt % of a reducing sugar relative to the total weight of the topical skin care composition; (B) alkali metal aromatic sulfonates; and (C) a carrier, wherein the reducing sugar (A) is dihydroxyacetone, erythrulose, or both, and the alkali metal aromatic sulfonate (B) is at least one selected from the group consisting of sodium 2-naphthalenesulfonate, sodium p-toluenesulfonate, sodium cumenesulfonate, sodium 4-dodecylbenzenesulfonate, and poly(sodium 4-styrenesulfonate). The weight ratio of the alkali metal aromatic sulfonate (B) to the reducing sugar (A) ((B):(A)) is 1:3 to 3:

2.

2. The topical skin care composition according to claim 1, wherein the alkali metal aromatic sulfonate (B) is sodium 2-naphthalenesulfonate.

3. The topical skin care composition according to claim 1, wherein the alkali metal aromatic sulfonate (B) is sodium cumene sulfonate.

4. The topical skin care composition according to any one of claims 1 to 3, wherein the weight ratio of the alkali metal aromatic sulfonate (B) to the reducing sugar (A) ((B):(A)) is 1:2 to 5:

4.

5. The topical skin care composition according to any one of claims 1 to 3, wherein the reducing sugar (A) is dihydroxyacetone.

6. The topical skin care composition according to any one of claims 1 to 3, wherein the carrier (C) comprises a aromatic alcohol.

7. The topical skin care composition according to any one of claims 1 to 3, wherein the carrier (C) comprises benzyl alcohol.

8. The topical skin care composition according to any one of claims 1 to 3, further comprising (D) an organic solvent.

9. The topical skin care composition of claim 8, wherein the organic solvent (D) comprises a polyol.

10. The topical skin care composition according to claim 8, wherein the weight ratio of the carrier (C) to the organic solvent (D) ((C):(D)) is 1:20 to 1:

2.

11. The topical skin care composition according to any one of claims 1 to 3, wherein the weight ratio of the alkali metal aromatic sulfonate (B) to the carrier (C) ((B):(C)) is 1:4 to 4:

1.

12. The topical skin care composition of any one of claims 1 to 3, which is substantially free of a cationic copolymer.

13. A method of adjusting skin color in a subject, the method comprising: topically applying the topical skin care composition according to any one of claims 1 to 12 to the skin of the subject, wherein the topical application reduces or increases the hue angle h° of the color by at least 0.5° compared to before the topical application.

14. A method of adjusting skin color in a subject, the method comprising: applying topically the topical skin care composition according to any one of claims 1 to 12 to the skin of a subject, The topical application reduces the lightness L* of the color by at least 10% and reduces or increases the hue angle h° of the color by at least 0.5°, respectively, compared to before the topical application.

15. A method for adjusting the color saturation of a subject's skin, the method comprising: topically applying the topical skin care composition according to any one of claims 1 to 12 to the skin of the subject, wherein the topical application increases the saturation C* of the color by at least 10% compared to before the topical application.

16. A collection of topical skin care products for retail sale, the collection comprising: (a) a first topical skin care composition comprising: (A) 0.1 to 30 wt % of a reducing sugar relative to the total weight of the topical skin care composition; (B) an alkali metal aromatic sulfonate; and (C) a carrier, wherein the reducing sugar (A) is dihydroxyacetone, erythrulose, or both, and the alkali metal aromatic sulfonate (B) is at least one selected from sodium 2-naphthalenesulfonate, sodium p-toluenesulfonate, sodium cumenesulfonate, sodium 4-dodecylbenzenesulfonate, and poly(sodium 4-styrenesulfonate), and wherein the weight ratio of the alkali metal aromatic sulfonate (B) to the reducing sugar (A) ((B):(A)) is 1:3 to 3:2, and (b) a second topical skin care composition comprising: (A) 0.1 to 30 wt % of a reducing sugar relative to the total weight of the topical skin care composition; (B) an alkali metal aromatic sulfonate; and (C) a carrier, wherein the reducing sugar (A) is dihydroxyacetone, erythrulose, or both, and the alkali metal aromatic sulfonate (B) is at least one selected from sodium 2-naphthalenesulfonate, sodium p-toluenesulfonate, sodium cumenesulfonate, sodium 4-dodecylbenzenesulfonate, and poly(sodium 4-styrenesulfonate), and wherein the weight ratio of the alkali metal aromatic sulfonate (B) to the reducing sugar (A) ((B):(A)) is 1:3 to 3:2, and wherein the amount of reducing sugar (A) present in the first topical skin care composition (a) relative to the total weight of the first topical skin care composition is less than the amount of reducing sugar (A) present in the second topical skin care composition (b) relative to the total weight of the second topical skin care composition.

17. The collection of claim 16, wherein the first topical skin care composition (a) and the second topical skin care composition (b) are separately packaged.

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