WO2022131141A1

WO2022131141A1 - Multi-phase composition comprising alpha hydroxy acid

Info

Publication number: WO2022131141A1
Application number: PCT/JP2021/045427
Authority: WO
Inventors: Mutsue HASHIMOTO; Wei Wang
Original assignee: L'oreal
Priority date: 2020-12-14
Filing date: 2021-12-03
Publication date: 2022-06-23

Abstract

The present invention relates to a multi-phase cosmetic composition comprising at least one oily phase and at least one water phase, comprising: (a) at least one polar oil, (b) at least one non-polar oil, (c) at least one alpha hydroxy acid, and (d) water, wherein the amount of the oily phase ranges from 4 to 10% by weight relative to the total weight of the composition; the weight ratio of the (a) polar oil to the (b) non-polar oil is more than 1, the amount of the (c) alpha hydroxy acid ranges from 1.5 to 5% by weight relative to the total weight of the composition, and the oily phase and the water phase form two separate layers at rest.

Description

DESCRIPTION

TITLE OF INVENTION

MULTI-PHASE COMPOSITION COMPRISING ALPHA HYDROXY ACID

TECHNICAL FIELD

The present invention relates to a multi-phase composition comprising at least one alpha hydroxy acid, preferably a cosmetic composition comprising the same.

BACKGROUND ART

Multi-phase compositions comprising a water phase and an oily phase have a benefit in their usability thanks to their low viscosity. In addition, they have another benefit in their appearance since they do not show a whitish appearance as emulsion compositions do.

For example, WO 2014/098254 discloses an anhydrous cosmetic composition, comprising: (a) at least one oily phase including at least one oil; (b) at least one alcohol phase including at least one alcohol; and (c) at least one nonionic surfactant phase including at least one nonionic surfactant, wherein the nonionic surfactant is selected from esters of polyols with fatty acids with a saturated or unsaturated chain containing for example from 8 to 24 carbon atoms, preferably 12 to 22 carbon atoms, and alkoxylated derivatives thereof with a number of alkyleneoxides of from 10 to 200.

Also, EP 3157949 Al discloses an anhydrous composition comprising: at least one oily phase (A) comprising at least one oil, at least one anhydrous non-oily phase (B) comprising at least one . polyol, at least one nonionic surfactant (i) having an HLB higher than 9, at least one nonionic surfactant (ii) having an HLB less than or equal to 9 in a quantity of at least 0.2% by weight relative to the weight of the anhydrous composition; wherein the nonionic surfactant (i) and the nonionic surfactant (ii) are present in the composition in a weight ratio of from 5.5 to 12.5, and wherein said phases (A) and (B) are visually distinctive from each other.

Hydroxy acid, such as alpha-hydroxy acid (AHA) is commonly used as an exfoliant/peeling agent in the cosmetics and dermatology fields. It is well known that AHA activates the protease in the stratum comeum to enhance the degradation of comeodesmosomes, while in the dermis layer, AHA can promote collagen formation. This subsequently leads to desquamation of skin, which improves the condition of skin. Furthermore, it has been reported that AHA also decreases facial pores and blackheads, most likely by targeting enzyme activation and protein functions linked to sebum production.

On the other hand, although the alpha hydroxyl acids at high concentration would result in a significant improvement of skin texture, it is also known the alpha hydroxyl acids bring about considerable discomfort upon application and after application (redness, stinging, and/or burning sensation). So far, there has been no report of formulations which suppresses skin discomfort while comprising alpha hydroxy acids at high concentration.

DISCLOSURE OF INVENTION

An objective of the present invention is to provide a multi-phase composition which can provide a good feeling on application to a keratinous substance such as skin and a great improvement in texture, while it suppresses a sensation of discomfort after application.

The above objective of the present invention can be achieved by a multi-phase cosmetic composition comprising at least one oily phase and at least one water phase, comprising:

(a) at least one polar oil,

(b) at least one non-polar oil,

(c) at least one alpha hydroxy acid, and

(d) water, wherein the amount of the oily phase ranges from 4 to 10% by weight relative to the total weight of the composition; the weight ratio of the (a) polar oil to the (b) non-polar oil is more than 1 , the amount of the (c) alpha hydroxy acid ranges from 1.5 to 5% by weight relative to the total weight of the composition, and the oily phase and the water phase form two separate layers at rest.

The (a) polar oils may comprise at least one ether oil.

The ether oil may be represented by the following formula:

R¹-O-R² wherein each of R¹ and R² independently denotes a linear, branched or cyclic C4-C24 alkyl group, preferably C₆-C ₁₈ alkyl group, and more preferably C₈-C₁₂ alkyl group.

The (b) non-polar oil may comprise at least one hydrocarbon oil.

The (b) non-polar oil may comprise at least one natural oil.

The weight ratio of the (a) polar oil to the (b) non-polar oil may be 1 or more, more preferably 1.5 or more, and even more preferably 2 or more, and in particular 2.3 or more, and/or may be 10 or less, preferably 7 or less, more preferably 5 or less, even more preferably 4 or less, and in particular 3 or less.

The (c) alpha hydroxy acid may comprise at least one alkyl alpha hydroxy acid.

The amount of the (a) polar oil may be 2% by weight or more, preferably 3% by weight or more, more preferably 4% by weight or more, and even more preferably 4.5% by weight or more, and/or may be 9.5% or less, preferably 9% by weight or less, more preferably 8% by weight or less, even more preferably 7% by weight or less, relative to the total weight of the composition.

The amount of the (b) non-polar oil may be 0.5% by weight or more, preferably 1% by weight or more, more preferably 1.5% by weight or more, and even more preferably 1.8% by weight or more, and/or may be 5% or less, preferably 4% by weight or less, more preferably 3% by weight or less, even more preferably 2% by weight or less, relative to the total weight of the composition.

The composition may be a bi-phase composition.

The composition may further comprise at least one cosmetically active ingredient. The composition may further comprise at least one cosmetically acceptable hydrophilic organic solvent.

The composition may comprise one or more particulate materials in an amount of less than 5% by weight or less, preferably 3% by weight or less, more preferably 1% by weight or less, even more preferably 0.5% by weight or less, and in particular 0.1% by weight or less, relative to the total weight of the composition, or the composition is free of any particulate materials.

The composition may comprise one or more surfactants in an amount of less than 5% by weight or less, preferably 3% by weight or less, more preferably 1% by weight or less, even more preferably 0.5% by weight or less, and in particular 0.1% by weight or less, relative to the total weight of the composition, or the composition is free of any surfactants.

The present invention also relates to a non-therapeutic cosmetic process for caring for and/or conditioning keratinous substances, such as skin, comprising: applying onto the keratinous substances a multi-phase cosmetic composition comprising at least one oily phase and at least one water phase, comprising:

(a) at least one polar oil,

(b) at least one non-polar oil,

(c) at least one alpha hydroxy acid, and

(d) water, wherein the amount of the oily phase ranges from 4 to 10% by weight relative to the total weight of the composition; the weight ratio of the (a) polar oil to the (b) non-polar oil is more than 1 , the amount of the (c) alpha hydroxy acid ranges from 1.5 to 5% by weight relative to the total weight of the composition, and the oily phase arid the water phase form two separate layers at rest.

BEST MODE FOR CARRYING OUT THE INVENTION

After diligent research, the inventors have surprisingly discovered that a combination of specific types of oils in a specific amount ratio can suppress skin discomfort due to an alpha hydroxy acid at a high concentration and provide a good sensation on application, thus completing the present invention.

Thus, the composition according to the present invention is a multi-phase cosmetic composition comprising at least one oily phase and at least one water phase, comprising:

(a) at least one polar oil

(b) at least one non-polar oil,

(c) at least one alpha hydroxy acid, and

(d) water, wherein the amount of the oily phase ranges from 4 to 10% by weight relative to the total weight of the composition; the weight ratio of the (a) polar oil to the (b) non-polar oil is more than 1 , the amount of the (c) alpha hydroxy acid ranges from 1.5 to 5% by weight relative to the total weight of the compo sition, and the oily phase and the water phase form two separate layers at rest. Hereinafter, the composition, process, and use according to the present invention will be explained in a more detailed manner.

[Composition]

The composition may be a cosmetic composition, preferably a cosmetic composition for a keratinous substance, and more preferably a cosmetic composition for caring for and/or conditioning a keratinous substance. The keratinous substance here means a material containing keratin as a main constituent element, and examples thereof include the skin, scalp, lips, and the like, and in particular skin.

The composition according to the present invention has a multi-phase form. The term “multi-phase” herein means a composition comprising at least two separate layers at rest, wherein each layer comprises or consists of a water phase, an oily phase, or an emulsion phase, such as a water-in-oil emulsion or an oil-in water emulsion phase. The multi-phase composition according to the present invention comprises at least a water phase and an oily phase, and preferably consists of a water phase and an oily phase. Therefore, the water phase of the composition forms a water layer at rest, and the oily phase of the composition forms an oily layer at rest, wherein the water layer and the oily layer are visually and/or macroscopically separated at rest in the composition.

In one preferred embodiment of the present invention, the composition can be a bi-phase composition comprising only two phases of a water phase and an oily phase, and the oily phase forms an oily layer and the water phase forms a water layer, which are visually and/or macroscopically separated at rest. The bi-phase composition according to the present invention has only two visually distinct layers at rest, the layers consisting of the continuous water phase and the continuous oily phase, respectively.

The term “water phase” here means a phase that is liquid at room temperature (25°C), comprising water and optionally comprising hydrophilic, water-soluble, or water-dispersible substances.

The term “oily phase” here means a phase that is liquid at room temperature, comprising at least one liquid oil at room temperature (25 °C) and atmospheric pressure (10⁵ Pa) and optionally comprising lipophilic, oil-soluble, or oil-dispersible substances. The term “liquid” means that a substance is liquid at 25°C under 1 atm.

The composition according to the present invention is intended for use after mixing each phase homogenously, for example, by simply shaking it. The composition according to the present invention may preferably be used as a skin-care cosmetic composition, in particular a leave-on type peeling composition. The composition according to the present invention may be intended for application onto a keratinous substance, preferably skin.

The amount of the water phase in the composition according to the present invention may be 50% by weight or more, preferably 60% by weight or more, more preferably 70% by weight, even more preferably 80% by weight or more, and in particular 85% by weight or more, and/or may be 99% by weight or less, preferably 97% by weight or less, more preferably 95% by weight or less, and even more preferably 93% by weight or less, relative to the total weight of the composition.

The amount of the oily phase ranges from 4 to 10% by weight relative to the total weight of the composition. The amount of the oily phase may preferably be 5% by weight or more, and more preferably 6% by weight or more, and/or may preferably be 9.5% by weight or less, and more preferably 9% by weight or less, relative to the total weight of the composition.

The composition according to the present invention comprises (a) at least one polar oil, (b) at least one non-polar oil, (c) at least one alpha hydroxy acid, and (d) water. The ingredients in the composition will be described in a detailed manner below.

(Polar Oil)

The composition according to the present invention comprises (a) at least one polar oil. A single type of the polar oil may be used, but two or more different types of the polar oils may be used in combination.

The (a) polar oil forms the oily phase of the present invention. Therefore, the oily phase of the present invention comprises at least one (a) polar oil. Therefore, the (a) polar oil forms an oily layer at rest in the composition.

The (a) polar oil may be selected from an ether oil, an ester oil, a silicone oil, fatty alcohol, and their combinations.

The ether oil may be volatile or non-volatile, preferably non-volatile.

It may be preferable to use, as the ether oil, dialkyl ethers such as those represented by the following formula:

R¹-O-R² wherein each of R¹ and R² independently denotes a linear, branched or cyclic C₄-C₂₄ alkyl group, preferably C₆-C₁₈ alkyl group, and more preferably C₈-C₁₂ alkyl group. It may be preferable that R¹ and R² be the same.

As the linear alkyl group, mention may be made of a butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, a nonyl group, a decyl group, an undecyl group, a dodecyl group, a tridecyl group, a tetradecyl group, a pentadecyl group, a hexadecyl group, a heptadecyl group, an octadecyl group, a nonadecyl group, an eicosyl group, a behenyl group, a docosyl group, a tricosyl group, and a tetracosyl group.

As the branched alkyl group, mention may be made of a 1 -methylpropyl group, a 2-methylpropyl group, at-butyl group, a 1,1 -dimethylpropyl group, a 3 -methylhexyl group, a 5-methylhexyl group, a 1 -ethylhexyl group, a 2-ethylhexylgroup, a 1 -butylpentyl group, a 5 -methyloctyl group, a

1 -ethylhexyl group, a 2-ethylhexyl group, a 1 -butylpentyl group, a 5 -methyloctyl group, a

2-butyloctyl group, an isotridecyl group, a 2-pentylnonyl group, a 2-hexyldecyl group, an isostearyl group, a 2-heptylundecyl group, a 2-octyldodecyl group, a 1,3-dimethylbutyl group, a

1-(l-methylethyl)-2-methylpropyl group, a 1,1,3,3-tetramethylbutyl group, a 3,5,5-trimethylhexyl group, a 1 -(2 -methylpropyl)-3 -methylbutyl group, a 3,7-dimethyloctyyl group, and a

2-(l,3,3-trimethylbutyl)-5,7,7-trimethyloctyl group.

As the cyclic alkyl group, mention may be made of a cyclohexyl group, a 3 -methylcyclohexyl group, and a 3,3,5-trimethylcyclohexyl group.

It may be preferable that the ether oil be selected from the group consisting of dicaprylyl ether, dicapryl ether, dilauryl ether, diisostearyl ether, dioctyl ether, nonyl phenyl ether, dodecyl dimethylbutyl ether, cetyl dimethylbutyl ether, cetyl isobutyl ether, and mixtures thereof.

It may be more preferable that the ether oil be selected from the group consisting of dicaprylyl ether, dicapryl ether, dilauryl ether, diisostearyl ether, dioctyl ether, and mixtures thereof.

The ester oils are liquid esters of saturated or unsaturated, linear or branched C₁-C₂₆ aliphatic monoacids or polyacids and of saturated or unsaturated, linear or branched C₁-C₂₆ aliphatic monoalcohols or polyalcohols, the total number of carbon atoms of the esters being greater than or equal to 10.

Preferably, for the esters of monoalcohols, at least one from among the alcohol and the acid from which the esters of the present invention are derived is branched.

Among the monoesters of monoacids and of monoalcohols, mention may be made of ethyl palmitate, ethyl hexyl palmitate, isopropyl palmitate, dicaprylyl carbonate, alkyl myristates such as isopropyl myristate or ethyl myristate, isocetyl stearate, 2-ethylhexyl isononanoate, isononyl isononanoate, isodecyl neopentanoate, and isostearyl neopentanoate.

Esters of C₄-C₂₂ dicarboxylic or tricarboxylic acids and of C₁-C₂₂ alcohols, and esters of monocarboxylic, dicarboxylic, or tricarboxylic acids and of non-sugar C₄-C₂₆ dihydroxy, trihydroxy, tetrahydroxy, or pentahydroxy alcohols may also be used.

Mention may especially be made of: diethyl sebacate; isopropyl lauroyl sarcosinate; diisopropyl sebacate; bis(2-ethylhexyl) sebacate; diisopropyl adipate; di-n-propyl adipate; dioctyl adipate; bis(2 -ethylhexyl) adipate; diisostearyl adipate; bis(2 -ethylhexyl) maleate; triisopropyl citrate; triisocetyl citrate; triisostearyl citrate; glyceryl trilactate; glyceryl trioctanoate; trioctyldodecyl citrate; trioleyl citrate; neopentyl glycol diheptanoate; diethylene glycol diisononanoate.

As ester oils, one can use sugar esters and diesters of C₆-C₃₀ and preferably C₁₂-C₂₂ fatty acids.

It is recalled that the term “sugar” means oxygen-bearing hydrocarbon-based compounds containing several alcohol functions, with or without aldehyde or ketone functions, and which comprise at least 4 carbon atoms. These sugars may be monosaccharides, oligosaccharides, or polysaccharides.

Examples of suitable sugars that may be mentioned include sucrose (or saccharose), glucose, galactose, ribose, fucose, maltose, fructose, mannose, arabinose, xylose, and lactose, and derivatives thereof, especially alkyl derivatives, such as methyl derivatives, for instance methylglucose.

The sugar esters of fatty acids may be chosen especially from the group comprising the esters or mixtures of esters of sugars described previously and of linear or branched, saturated or unsaturated C₆-C₃₀ and preferably C₁₂-C₂₂ fatty acids. If they are unsaturated, these compounds may have one to three conjugated or non-conjugated carbon-carbon double bonds.

The esters according to this variant may also be selected from monoesters, diesters, triesters, tetraesters, and polyesters, and mixtures thereof.

These esters may be, for example, oleates, laurates, palmitates, myristates, behenates, cocoates, stearates, linoleates, linolenates, caprates, and arachidonates, or mixtures thereof such as, especially, oleopalmitate, oleostearate, and palmitostearate mixed esters, as well as pentaerythrityl tetraethyl hexanoate.

More particularly, use is made of monoesters and diesters and especially sucrose, glucose, or methylglucose monooleates or dioleates, stearates, behenates, oleopalmitates, linoleates, linolenates, and oleostearates.

An example that may be mentioned is the product sold under the name Glucate® DO by the company Amerchol, which is a methylglucose dioleate.

As examples of preferable ester oils, mention may be made of, for example, diisopropyl adipate, dioctyl adipate, 2-ethylhexyl hexanoate, ethyl laurate, cetyl octanoate, octyldodecyl octanoate, isodecyl neopentanoate, myristyl propionate, 2-ethylhexyl 2-ethylhexanoate, 2-ethylhexyl octanoate, 2-ethylhexyl caprylate/caprate, methyl palmitate, ethyl palmitate, isopropyl palmitate, dicaprylyl carbonate, isopropyl lauroyl sarcosinate, isononyl isononanoate, ethylhexyl palmitate, isohexyl laurate, hexyl laurate, isocetyl stearate, isopropyl isostearate, isopropyl myristate, isodecyl oleate, glyceryl tri(2-ethylhexanoate), pentaerythrithyl tetra(2-ethylhexanoate), 2-ethylhexyl succinate, diethyl sebacate, and mixtures thereof.

As examples of silicone oils, mention may be made of, for example, linear organopolysiloxanes such as dimethylpolysiloxane, methylphenylpolysiloxane, methylhydrogenpolysiloxane, and the like; cyclic organopolysiloxanes such as cyclohexasiloxane, octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane, dodecamethylcyclohexasiloxane, and the like; and mixtures thereof.

Preferably, the silicone oil is chosen from liquid polydialkylsiloxanes, especially liquid polydimethylsiloxanes (PDMS) and liquid polyorganosiloxanes comprising at least one aryl group.

These silicone oils may also be organomodified. The organomodified silicones that can be used in accordance with the present invention are silicone oils as defined above and comprise in their structure one or more organofunctional groups attached via a hydrocarbon-based group.

Organopolysiloxanes are defined in greater detail in Walter Noll’s Chemistry and Technology of Silicones (1968), Academic Press. They may be volatile or non-volatile.

When they are volatile, the silicones are more particularly chosen from those having a boiling point of between 60°C and 260°C.

Non-volatile polydialkylsiloxanes may also be used. These non-volatile silicones are more particularly chosen from polydialkylsiloxanes, among which mention may be made mainly of polydimethylsiloxanes containing trimethylsilyl end groups.

Among these polydialkylsiloxanes, mention may be made, in a non-limiting manner, of the following commercial products: the Silbione® oils of the 47 and 70 047 series or the Mirasil® oils sold by Rhodia, for instance the oil 70047 V 500000; the oils of the Mirasil® series sold by the company Rhodia; the oils of the 200 series from the company Dow Coming, such as DC200 with a viscosity of 60 000 mm²/s; and the Viscasil® oils from General Electric and certain oils of the SF series (SF 96, SF 18) from General Electric.

Mention may also be made of polydimethylsiloxanes containing dimethylsilanol end groups known under the name dimethiconol (CTFA), such as the oils of the 48 series from the company Rhodia.

Among the silicones containing aryl groups, mention may be made of polydiarylsiloxanes, especially polydiphenylsiloxanes and polyalkylarylsiloxanes such as phenyl silicone oil.

Examples that may be mentioned include the products sold under the following names: the Silbione® oils of the 70641 series from Rhodia; the oils of the Rhodorsil® 70 633 and 763 series from Rhodia; the oil Dow Coming 556 Cosmetic Grade Fluid from Dow Coming; the silicones of the PK series from Bayer, such as the product PK20; certain oils of the SF series from General Electric, such as SF 1023, SF 1154, SF 1250, and SF 1265.

As the phenyl silicone oil, phenyl trimethicone is preferable.

The organomodified liquid silicones may especially contain polyethyleneoxy and/or polypropyleneoxy groups. Mention may thus be made of the silicone KF-6017 proposed by Shin-Etsu, and the oils Silwet® L722 and L77 from the company Union Carbide.

The term “fatty” in the fatty alcohol means the inclusion of a relatively large number of carbon atoms. Thus, alcohols which have 4 or more, preferably 6 or more, and more preferably 12 or more carbon atoms are encompassed within the scope of fatty alcohols. The fatty alcohol may be saturated or unsaturated. The fatty alcohol may be linear or branched.

The fatty alcohol may have the structure R-OH wherein R is chosen from saturated and unsaturated, linear and branched radicals containing from 4 to 40 carbon atoms, preferably from 6 to 30 carbon atoms, and more preferably from 12 to 20 carbon atoms. In at least one embodiment, R may be chosen from C₁₂-C₂₀ alkyl and C₁₂-C₂₀ alkenyl groups. R may or may not be substituted with at least one hydroxyl group.

As examples of the fatty alcohol, mention may be made of lauryl alcohol, cetyl alcohol, stearyl alcohol, isostearyl alcohol, behenyl alcohol, undecylenyl alcohol, myristyl alcohol, octyldodecanol, hexyldecanol, oleyl alcohol, linoleyl alcohol, palmitoleyl alcohol, arachidonyl alcohol, erucyl alcohol, and mixtures thereof.

It is preferable that the fatty alcohol be a saturated fatty alcohol.

Thus, the fatty alcohol may be selected from straight or branched, saturated or unsaturated C₆-C₃₀ alcohols, preferably straight or branched, saturated C₆-C₃₀ alcohols, and more preferably straight or branched, saturated C₁₂-C₂₀ alcohols.

The term “saturated fatty alcohol” here means an alcohol having a long aliphatic saturated carbon chain. It is preferable that the saturated fatty alcohol be selected from any linear or branched, saturated C₆-C₃₀ fatty alcohols. Among the linear or branched, saturated C₆-C₃₀ fatty alcohols, linear or branched, saturated C₁₂-C₂₀ fatty alcohols may preferably be used. Any linear or branched, saturated C₁₆-C₂₀ fatty alcohols may be more preferably used. Branched C₁₆-C₂₀ fatty alcohols may be even more preferably used.

As examples of saturated fatty alcohols, mention may be made of lauryl alcohol, cetyl alcohol, stearyl alcohol, isostearyl alcohol, behenyl alcohol, undecylenyl alcohol, myristyl alcohol, octyldodecanol, hexyldecanol, and mixtures thereof. In one embodiment, cetyl alcohol, stearyl alcohol, octyldodecanol, hexyldecanol, or a mixture thereof (e.g., cetearyl alcohol) as well as behenyl alcohol, can be used as a saturated fatty alcohol.

In one preferred embodiment of the present invention, the (a) polar oil is selected from ether oils as mentioned above.

The (a) polar oil(s) may be present in an amount of 1% by weight or more, more preferably 2% by weight or more, even more preferably 3% by weight or more, and in particular 4% by weight or more, and/or may be present in an amount of 9% by weight or less, preferably 8% by weight or less, more preferably 7.5% by weight or less, and in particular 7% by weight or less, relative to the total weight of the composition.

(Non-polar Oil)

The composition according to the present invention comprises (b) at least one non-polar oil. A single type of the non-polar oil may be used, but two or more different types of the non-polar oils may be used in combination.

The (b) non-polar oil forms the oily phase of the present invention. Therefore, the oily phase of the present invention comprises at least one (b) non-polar oil. Therefore, the (b) non-polar oil forms an oily layer at rest in the composition.

The (b) non-polar oil may be selected from hydrocarbon oils.

Hydrocarbon oils may be chosen from: linear or branched, optionally cyclic, C₆-C₁₆ lower alkanes. Examples that may be mentioned include hexane, undecane, dodecane, tridecane, and isoparaffins, for instance isohexadecane, isododecane, and isodecane; and linear or branched hydrocarbons containing more than 16 carbon atoms, such as liquid paraffins, liquid petroleum jelly, polydecenes and hydrogenated polyisobutenes such as Parleam®, and squalane.

As preferable examples of hydrocarbon oils, mention may be made of, for example, linear or branched hydrocarbons such as isohexadecane, isododecane, squalane, mineral oil (e.g., liquid paraffin), paraffin, vaseline or petrolatum, naphthalenes, and the like; hydrogenated polyisobutene, isoeicosan, and decene/butene copolymer; and mixtures thereof.

In one preferred embodiment of the present invention, the (b) non-polar oil may be selected from those of natural oils, for example oils of plant origin, such as squalene and triglycerides.

In yet another preferred embodiment of the present invention, the oily phase of the composition comprises a combination of the (a) polar oil selected from ether oils and the (b) non-polar oil selected from hydrocarbon oils, such as explained above.

In yet another preferred embodiment of the present invention, the oily phase of the composition comprises a combination of the (a) polar oil selected from ether oils and the (b) non-polar oil selected from natural oils, such as explained above.

The (b) non-polar oil(s) may be present in an amount of 0.5% by weight or more, more preferably 1% by weight or more, even more preferably 1.5% by weight or more, and in particular 1.8% by weight or more, and/or may be present in an amount of 8% by weight or less, preferably 6% by weight or less, more preferably 5% by weight or less, and in particular 3% by weight or less, relative to the total weight of the composition.

In the present invention, the weight ratio of the (a) polar oil to the (b) non-polar oil in the composition is more than 0.5. In preferred embodiments of the present invention, the weight ratio of the (a) polar oil to the (b) non-polar oil in the composition may be 1 or more, more preferably 1.5 or more, and even more preferably 2 or more, and in particular 2.3 or more, and/or may be 10 or less, preferably 7 or less, more preferably 5 or less, even more preferably 4 or less, and in particular 3 or less.

(Alpha Hydroxy Acid)

The composition according to the present invention may comprise at least one (c) alpha hydroxy acid. A single type of alpha hydroxy acid may be used, but two or more different types of the alpha hydroxy acids may be used in combination.

The (c) alpha hydroxy acid forms the water phase of the present invention. Therefore, the water phase of the present invention comprises at least one (c) alpha hydroxy acid. Therefore, the (c) alpha hydroxy acid forms a water layer at rest in the composition.

The term “alpha hydroxy acid”, “a-hydroxy acid”, or “AHA” here means a carboxylic acid which has at least one hydroxyl group on the adjacent (alpha) carbon atom.

The α-hydroxy acid may be represented by the following chemical formula:

(R_a)(R_b)C(OH)COOH where R_a and R_b are H, F, Cl, Br, I, alkyl, aralkyl or aryl group of saturated or unsaturated, isomeric or non-isomeric, straight or branched chain or cyclic form, having 1 to 25 carbon atoms, and in addition R_a and R_b may carry OH, CHO, COOH and alkoxyl group having 1 to 9 carbon atoms.

The hydrogen atom attached to the carbon atom may be substituted by F, Cl, Br, I, or a lower alkyl, aralkyl, aryl or alkoxyl group having 1 to 9 carbon atoms. The alpha hydroxy acid may be present as a free acid or in lactone form, or in a partial salt form with an organic base or an inorganic alkali. The alpha hydroxy acids may exist as stereoisomers such as D, L, DL and meso forms.

When R_a and R_b are alkyl, they independently can be within any of the groups of C₁-C₅, C₆-C₁₀, C₁₁ -C ₁₅ , C ₁₆-C₂₀, C₂₁ -C₂₅ and C₂₆-C₂₉. Compounds within the above chemical formula thus include all of the possible combinations of R_a and R_b. Included within the foregoing is a subgenus of compounds having R_a and R_b independently selected from C₁-C₁₂,

Typical alkyl, aralkyl, aryl and alkoxyl groups for R_a and R_b include methyl, ethyl, propyl, propyl, isopropyl, butyl, pentyl, octyl, lauryl, stearyl, benzyl, phenyl, methoxyl, and ethoxyl.

The alpha hydroxy acids of the first group may be subdivided into

( 1 ) alkyl alpha hydroxy acids, (2) aralkyl and aryl alpha hydroxy acids,

(3) polyhydroxy alpha hydroxy acids,

(4) polycarboxylic alpha hydroxy acids, and

(5) miscellaneous alpha hydroxy acids. The following are representative alpha hydroxy acids in each subgroup.

(1) Alkyl Alpha Hydroxy Acids: 2-hydroxyethanoic acid (glycolic acid), 2-hydroxypropanoic acid (lactic acid), 2-methyl 2-hydroxypropanoic acid (methyllactic acid), 2-hydroxybutanoic acid, 2-hydroxypentanoic acid, 2-hydroxyhexanoic acid, 2-hydroxyheptanoic acid, 2-hydroxyoctanoic acid, 2-hydroxynonanoic acid, 2-hydroxydecanoic acid, 2-hydroxyundecanoic acid, 2-hydroxydodecanoic acid, 2-hydroxytetradecanoic acid, 2-hydroxyhexadecanoic acid, 2-hydroxyoctadecanoic acid, 2-hydroxyeicosanoic acid (alpha hydroxyarachidonic acid), 2-hydroxytetraeicosanoic acid (cerebronic acid), 2-hydroxytetraeicosenoic acid (alpha hydroxynervonic acid) and 2,4-dihydroxy-3,3-dimethylbutanoic acid (pantoic acid) (2) Aralkyl and Aryl Alpha Hydroxy Acids: 2-phenyl 2-hydroxyethanoic acid (mandelic acid);

2,2-diphenyl 2-hydroxyethanoic acid (benzilic acid), 3 -phenyl 2-hydroxypropanoic acid (phenyllactic acid), 2-phenyl 2-methyl 2-hydroxyethanoic acid (atrolactic acid) and 4-hydroxymandelic acid.

(3) Polyhydroxy Alpha Hydroxy Acids: 2,3-dihydroxypropanoic acid (glyceric acid); 2,3,4-trihydroxybutanoic acid (isomers; erythronic acid, threonic acid);

2,3,4,5-tetrahydroxypentanoic acid (isomers; ribonic acid, arabinoic acid, xylonic acid, lyxonic acid); 2,3,4,5,6-pentahydroxyhexanoic acid (isomers; allonic acid, altronic acid, gluconic acid, mannoic acid, gulonic acid, idonic acid, galactonic acid, talonic acid);

2,3,4,5,6,7-hexahydroxyheptanoic acid (isomers; glucoheptonic acid, galactoheptonic acid, mannoheptonic acid, etc.)

(4) Polycarboxylic Alpha Hydroxy Acids: 2-hydroxypropane- 1,3 -dioic acid (tartronic acid);

2-hydroxybutane- 1,4-dioic acid (malic acid); 2-hydroxy-2-methylbutane- 1,4-dioic acid (citramalic acid); 2, 3 -dihydroxybutane- 1,4-dioic acid (tartaric acid); 2, 3, 4-trihydroxypentane- 1,5-dioic acid (isomers; ribaric acid, arabaric acid, xylaric acid, lyxaric acid); 2,3,4,5-tetrahydroxyhexane-l,6-dioic acid (isomers; glucaric acid, galactaric acid, mannaric acid, allaric acid, altraric acid, gularic acid, idaric acid, talaric acid);

2-hydroxy-l,2,3-propanetricarboxylic acid (citric acid); 1 -hydroxy- 1, 2, 3 -propanetricarboxylic acid (isocitric acid); 1 -hydroxy- 1, 2, 4-butanetricarboxylic acid (homoisocitric acid);

2-hydroxy-3-hexadecyl-l,2,3-propanetricarboxylic acid (n-hexadecyl citric acid; agaricic acid). (5) Miscellaneous Alpha Hydroxy Acids: glyceruronic acid, erythruronic acid, threuronic acid;

2,3,4-trihydroxypentanuronic acids (isomers; riburonic acid, arabinuronic acid, xyluronic acid, lyxuronic acid); 2,3,4,5-tetrahydroxyhexanuronic acid (isomers; alluronic acid, altruronic acid, glucuronic acid, mannuronic acid, guluronic acid, iduronic acid, galacturonic acid, taluronic acid); 2,3,4,5,6-pentahydroxyheptanuronic acid (isomers; alloheptanuronic acid, altroheptanuronic acid, glucoheptanuronic acid, mannoheptanuronic acid, guloheptanuronic acid, idoheptanuronic acid, galactoheptanuronic acid, taloheptanuronic acid).

The alpha hydroxy acid may be selected from, for example, the group consisting of glycolic acid, lactic acid, malic acid, citric acid, tartaric acid, mandelic acid, gluconic acid and mixtures thereof, preferably from the group consisting of glycolic acid, lactic acid and mixtures thereof, more preferably from glycolic acid.

The (c) alpha hydroxy acid(s) is(are) present in the composition in an amount of 1.5 to 5% by weight relative to the total weight of the composition. In preferred embodiments of the present invention, the (c) alpha hydroxy acid(s) may be present in an amount of 2% by weight or more, more preferably 3% by weight or more, even more preferably 3.5% by weight or more, and in particular 4% by weight or more, and/or may be present in an amount of 4.8% by weight or less, preferably 4.6% by weight or less, and in particular 4.4% by weight or less, relative to the total weight of the composition.

(Water)

The composition according to the present invention comprises (d) water. The water forms the water phase of the present invention. Therefore, the water phase of the composition comprises water. The (e) water forms a water layer at rest in the composition.

The (d) water may be present in an amount of 50% by weight or more, preferably 55% by weight or more, more preferably 60% by weight or more, even more preferably 65% by weight or more, preferentially 70% by weight or more, and in particular 75% by weight or more, and/or may be present in an amount of 95% by weight or less, preferably 90% by weight or less, more preferably 85% by weight or less, and in particular 80% by weight or less, relative to the total weight of the composition.

(Hydrophilic Organic Solvent)

The composition according to the present invention may comprise at least one cosmetically acceptable hydrophilic organic solvent,

The term “hydrophilic” here means substances having a solubility of at least 1 g/L, preferably at least 10 g/L, and more preferably at least 100 g/L, in water at room temperature (25°C) and atmospheric pressure (10⁵ Pa). Therefore, the cosmetically acceptable hydrophilic organic solvent is included in the water phase, if present.

The cosmetically acceptable hydrophilic organic solvent(s) may include, for example, substantially linear or branched lower mono-alcohols having from 1 to 8 carbon atoms, such as ethanol, propanol, butanol, isopropanol, and isobutanol; aromatic alcohols, such as benzyl alcohol and phenylethyl alcohol; polyols or polyol ethers, such as propylene glycol, dipropylene glycol, isoprene glycol, butylene glycol, glycerine, propanediol, pentylene glycol, caprylyl glycol, sorbitol, ethylene glycol monomethyl, monoethyl and monobutyl ethers, propylene glycol ethers, propylene glycol monomethylether, diethylene glycol alkyl ethers, such as diethylene glycol monoethylether or monobutylether; polyethylene glycols, such as PEG-4, PEG-6, and PEG-8, and their derivatives, and a combination thereof.

The amount of the cosmetically acceptable hydrophilic organic solvent(s) in the composition according to the present invention may be from 1% by weight or more, preferably 3% by weight or more, more preferably 5% by weight or more, even more preferably 7% by weight or more, and in particular 10% by weight or more, and/or may be 30% by weight or less, preferably 20% by weight or less, and more preferably 15% by weight or less, relative to the total weight of the composition. (pH Adjusting Agent)

The pH of the composition according to the present invention may be adjusted to the desired value using at least one pH adjusting agent, such as an acidifying or a basifying agent, for example, which are commonly used in cosmetic products.

The pH of the composition according to the present invention may be 8.0 or less, preferably 7.0 or less, more preferably 6.0 or less, even more preferably 5.0 or less, and in particular 4.5 or less, and/or may be 2.5 or more, preferably 3.0 or more, more preferably 3.5 or more, and in particular 4.0 or more at 25°C.

Among the acidifying agents, mention may be made, by way of example, of mineral or organic acids such as hydrochloric acid, ortho-phosphoric acid, sulfuric acid, carboxylic acids such as acetic acid, tartaric acid, citric acid, and lactic acid, and sulfonic acids.

Among the basifying agents, mention may be made, by way of example, of hydroxides of an alkali metal or an alkaline-earth metal, for instance sodium hydroxide or potassium hydroxide; quaternary ammonium hydroxides and guanidinium hydroxide; alkali metal silicates, such as sodium metasilicates; amino acids, preferably basic amino acids, such as arginine, lysine, ornithine, citrulline and histidine; carbonates and bicarbonates, particularly of a primary amine, secondary amine or tertiary amine, of an alkali metal or alkaline-earth metal, or of ammonium; and the compounds of the following formula:

in which

W is a C₁-C₆ alkylene residue optionally substituted with a hydroxyl group or a C₁-C₆ alkyl group; Rx, Ry, Rz and Rt, which may be identical or different, represent a hydrogen atom or a C₁-C₆ alkyl, C₁-C₆ hydroxyalkyl or C₁-C₆ aminoalkyl group. Mention may especially be made of 1 ,3 -diaminopropane, 1 ,3 -diamino-2 -propanol, spermine and spermidine.

The pH adjusting agent(s) may be used in an amount ranging from 0.001% to 15% by weight, preferably from 0.01% to 12% by weight, and more preferably from 0.1% to 10% by weight, relative to the total weight of the composition.

(Active Ingredient)

The composition according to the present invention may comprise at least one optional cosmetically active ingredient. The term “active ingredient” used herein means an organic compound having any cosmetic or dermatological effects on a keratinous substance, such as skin. Well-known cosmetic active ingredients in the cosmetic field can be used as the optional active ingredients. Preferably, the additional cosmetic ingredient is an active ingredient for caring for or conditioning keratinous substances, such as skin. For example, the active ingredients are for improving a condition of keratinous substances, such as skin.

Preferably the cosmetically active ingredient is included in the water phase, if present.

As the skin- whitening ingredients, mention can be made of, for example, L-ascorbic acids and their derivatives, a salicylic acid and their derivatives, such as alkoxysalicylic acids, hydroquinone glycosides and their derivatives, tranexamic acids and their derivatives, resorcinol derivatives, koji acids and their derivatives, cinnamaldehyde or its derivatives, and ellagic acid. As the antiaging ingredients, mention can be made, for example, vitamins such as retinol, and saponin, and allantoin. As the antioxidant ingredients, mention can be made of, for example, carotenoids such as β-cryptoxanthin, and tocopherol and its derivatives, and flavonoids.

The amount of the optional active ingredient(s) in the composition according to the present invention may be from 0.01% by weight or more, preferably 0.05% by weight or more, more preferably 0.1% by weight or more, and even more preferably 0.15% by weight or more, and may be 10% by weight or less, preferably 5% by weight or less, more preferably 3% by weight or less, and even more preferably 1% by weight or less, relative to the total weight of the composition.

(Adjuvants)

The composition according to the present invention may also comprise any adjuvant(s) usually used in the field of cosmetics, chosen, for example, from anionic, cationic, nonionic or amphoteric polymers, anionic, cationic, nonionic or amphoteric surfactants, hydrophobic organic solvents, gums, resins, thickeners, antioxidants, buffers, organic or inorganic fillers, preserving agents, such as phenoxyethanol, co-preservatives, opacifying agents, fragrances, neutralizers, antiseptics, UV-screening agents, stabilizers or electrolytes, such as sodium chloride, chelating agents, dispersing agents, dyes and/or pigments, emollients or collagen-protecting agents, and mixtures thereof.

The adjuvants may be present in the composition of the present invention in an amount preferably ranging from 0.01% to 30% by weight, preferably from 0.1% to 20% by weight, and more preferably from 0.5% to 10% by weight, relative to the total weight of the composition.

In another preferred embodiment of the present invention, the composition preferably includes one or more particulate materials, such as fillers, in an amount of less than 5% by weight or less, preferably 3% by weight or less, more preferably 1% by weight or less, even more preferably 0.5% by weight or less, and in particular 0.1% by weight or less, relative to the total weight of the composition,. In another preferred embodiment of the present invention, the composition is free of any particulate materials.

In another preferred embodiment of the present invention, the composition preferably includes one or more surfactants in an amount of less than 5% by weight or less, preferably 3% by weight or less, more preferably 1% by weight or less, even more preferably 0.5% by weight or less, and in particular 0.1% by weight or less, relative to the total weight of the composition,. In another preferred embodiment of the present invention, the composition is free of any surfactants.

The composition according to the present invention can be prepared by mixing the above-described essential and optional ingredients in a conventional manner. It is possible to further comprise mixing any of the optional ingredients and heating the composition until an ingredient is dissolved.

[Cosmetic Process and Method]

The present invention also relates to a non-therapeutic method or process, preferably a cosmetic method or process, and more preferably a cosmetic method or process for caring for and/or conditioning keratinous substances, such as skin, scalp, and lips, in particular skin, comprising: applying onto the keratinous substance a multi-phase cosmetic composition comprising at least one oily phase and at least one water phase, comprising:

(a) at least one polar oil,

(b) at least one non-polar oil,

(c) at least one alpha hydroxy acid, and

(a) at least one ether oil,

(b) at least one hydrocarbon oil or natural oil, which is an non-polar oil,

(c) at least one alpha hydroxy acid, and

The process or method according to the present invention can further comprise another step of mixing the water phase and the oily phase of the present invention prior to the application on the keratinous substance, so as to be a homogenous composition.

The same explanations for the composition, the (a) polar oil, the (b) non-polar oil, the (c) alpha hydroxy acid, and the (d) water in the composition according to the present invention above can be applied to the composition, the (a) polar oil, the (b) non-polar oil, the (c) alpha hydroxy acid, and the (d) water for the method, process, and use according to the present invention. The composition used in the process, method, and use according to the present invention may include any of the optional ingredients as explained above for the composition according to the present invention.

EXAMPLES

The present invention will be described in more detail by way of examples which however should not be construed as limiting the scope of the present invention.

[Compositions]

Homogeneous solution compositions according to the Examples and Comparative Examples were prepared by mixing the ingredients as listed in Tables 1 to 4 with a magnetic stirrer at room temperature (25°C). The numerical values for the amounts of the ingredients shown in Table 1 are all based on “% by weight” as active raw materials.

[Evaluation]

(Skin Discomfort)

Each of the compositions was shaken 10 times in a container so as to be homogenous and then was applied on panel members’ facial skin (n=6) with a cotton pad and in a controlled amount. Skin discomfort sensation, such as redness, stinging, and/or burning sensation, for each composition was assessed after the application under the following criteria.

Very Good: No skin discomfort

Good: Slight skin discomfort but acceptable

Poor: Skin discomfort

Very Poor: Obvious skin discomfort

(Skin Sensation on Application)

Each of the compositions was shaken 10 times in a container so as to be homogenous and then was applied on panel members’ facial skin (n=6) with a cotton pad and in a controlled amount. Skin sensation on application was evaluated for each compositions under the following criteria.

Very Good: Moist but not greasy

Good: Moist but slightly greasy

Poor: No moist but greasy feeling

Very Poor: No moist feeling at all but very greasy feeling

(Skin Texture Improvement)

The skin texture improvement after application was evaluated by a trained expert protocol. Each of the compositions was shaken 10 times in a container so as to be homogenous and then was applied on panel members’ facial skin (n=6) with a cotton pad and in a controlled amount. Skin texture improvement for each composition was assessed after two weeks from the application under the following criteria.

Good: Significant improvement

Poor: No improvement at all

(Formula Structure)

The appearance of each of the compositions was observed with the naked eye to determine whether it has a multi-phase (bi-phase) structure or not.

The results are shown in Table 1 below. Table 1

As can be seen from Table 1 , the compositions according to the Eexamples, which include the specific combination of the (a) polar oil, the (b) non-polar oil, the (c) alpha hydroxy acid, and the (d) water in the specific amounts according to the present invention, showed excellent skin sensation on application and great improvement in skin texture after application, while it suppressed skin discomfort due to the alpha hydroxy acid at a high concentration.

On the other hand, the composition according to Comparative Example 1, which does not include alpha hydroxy acid, did not show improvement in skin texture at all. The composition according to Comparative Example 2, which does not include oils, did not show a tolerable suppression of skin discomfort and provided an uncomfortable feeling on application. The composition according to Comparative Example 3, which includes a polar oil and a non-polar oil in a weight ratio out of the scope of the present invention, and the composition according to Comparative Example 4, which does not include a non-polar oil, did not show a good feeling on application. The composition according to Comparative Example 5, which does not include a polar oil and a non-polar oil and the total oil concentration is less than 4%, and the composition according to Comparative Example 7, which includes an alpha hydroxy acid in a too high concentration, did not suppress skin discomfort after application. The composition according to Comparative Example 6, which includes an oily phase in a too high concentration, did not show a comfortable skin sensation on application due to a greasy feeling.

Accordingly, it can be concluded that the compositions according to the present invention are very suitable as cosmetic compositions for caring and/or conditioning keratinous substances, such as skin, since they can provide cosmetic effects and a satisfactory sensation on application, while it can suppress skin discomfort.

Claims

1. A multi-phase cosmetic composition comprising at least one oily phase and at least one water phase, comprising:

(a) at least one polar oil,

(b) at least one non-polar oil,

(c) at least one alpha hydroxy acid, and

2. The composition according to Claim 1 , wherein the (a) polar oils comprises at least one ether oil.

3. The composition according to Claim 2, wherein the ether oil is represented by the following formula:

R¹-O-R² wherein each of R¹ and R² independently denotes a linear, branched or cyclic C₄-C₂₄ alkyl group, preferably C₆-C₁₈ alkyl group, and more preferably C8-C₁₂ alkyl group.

4. The composition according to any one of the preceding claims, wherein the (b) non-polar oil comprises at least one hydrocarbon oil.

5. The composition according to any one of the preceding claims, wherein the (b) non-polar oil Comprises at least one natural oil.

6. The composition according to any one of the preceding claims, wherein the weight ratio of the (a) polar oil to the (b) non-polar oil is 1 or more, more preferably 1.5 or more, and even more preferably 2 or more, and in particular 2.3 or more, and/or is 10 or less, preferably 7 or less, more preferably 5 or less, even more preferably 4 or less, and in particular 3 or less.

7. The composition according to any one of the preceding claims, wherein the (c) alpha hydroxy acid comprises at least one alkyl alpha hydroxy acid.

8. The composition according to any one of the preceding claims, wherein the amount of the (a) polar oil is 2% by weight or more, preferably 3% by weight or more, more preferably 4% by weight or more, and even more preferably 4.5% by weight or more, and/or is 9.5% or less, preferably 9% by weight or less, more preferably 8% by weight or less, even more preferably 7% by weight or less, relative to the total weight of the composition.

9. The composition according to any one of the preceding claims, wherein the amount of the (b) non-polar oil is 0.5% by weight or more, preferably 1% by weight or more, more preferably 1.5% by weight or more, and even more preferably 1.8% by weight or more, and/or is 5% or less, preferably 4% by weight or less, more preferably 3% by weight or less, even more preferably 2% by weight or less, relative to the total weight of the composition.

10. The composition according to any one of the preceding claims, wherein the composition is a bi-phase composition.

11. The composition according to any one of the preceding claims, wherein the composition further comprises at least one cosmetically active ingredient.

12. The composition according to any one of the preceding claims, wherein the composition further comprises at least one cosmetically acceptable hydrophilic organic solvent.

13. The composition according to any one of the preceding claims, wherein the composition comprises one or more particulate materials in an amount of less than 5% by weight or less, preferably 3% by weight or less, more preferably 1% by weight or less, even more preferably 0.5% by weight or less, and in particular 0.1% by weight or less, relative to the total weight of the composition, or the composition is free of any particulate materials.

14. The composition according to any one of the preceding claims, wherein the composition comprises one or more surfactants in an amount of less than 5% by weight or less, preferably 3% by weight or less, more preferably 1% by weight or less, even more preferably 0.5% by weight or less, and in particular 0.1% by weight or less, relative to the total weight of the composition, or the composition is free of any surfactants.

15. A non-therapeutic cosmetic process for caring for and/or conditioning keratinous substances, such as skin, comprising: applying onto the keratinous substances a multi-phase cosmetic composition comprising at least one oily phase and at least one water phase, comprising:

(a) at least one polar oil,

(b) at least one non-polar oil,

(c) at least one alpha hydroxy acid, and

(d) water, wherein the amount of the oily phase ranges from 4 to 10% by weight relative to the total weight of the composition; the weight ratio of the (a) polar oil to the (b) non-polar oil is more than 1, the amount of the (c) alpha hydroxy acid ranges from 1.5 to 5% by weight relative to the total weight of the composition, and the oily phase and the water phase form two separate layers at rest.