WO2014097361A1

WO2014097361A1 - Method for reducing skin pore appearance and mattifying skin and an aqueous composition containing fusiform particles for skincare

Info

Publication number: WO2014097361A1
Application number: PCT/JP2012/008179
Authority: WO
Inventors: David Amar; Makoto Saito
Original assignee: L'oreal
Priority date: 2012-12-20
Filing date: 2012-12-20
Publication date: 2014-06-26
Also published as: JP2016504267A; BR112015014544A2; CN104955523A

Abstract

A method for reducing skin pore appearance and/or mattifying skin, an aqueous skincare composition containing fusiform particles, and a method for taking care of and/or for treating oily skin are provided. The fusiform particles are made of an organosilicone having a crosslinked polysiloxane structure and an average diameter along a major axis L₁ of approximately 0.05 to 20 micrometers, an average diameter along a minor axis L₂ of approximately 0.03 to 15 micrometers, L₁/L₂ being approximately 1.1 to 3.3, and the aqueous skincare composition are used in the methods.

Description

METHOD FOR REDUCING SKIN PORE APPEARANCE AND MATTIFYING SKIN AND AN AQUEOUS COMPOSITION CONTAINING FUSIFORM PARTICLES FOR SKINCARE

The present invention relates to a method for reducing skin pore appearance and/or mattifying skin and an aqueous skincare composition containing fusiform, or "rugby ball"-shaped, particles, in particular for reducing skin pore appearance and for mattifying skin. The present invention also relates to a method for taking care of and/or for treating oily skin.

Oily skin is regarded as one of the greatest beauty concerns due to the shiny appearance and pore visibility associated with this skin type. While there are already many skincare products on the market for oily skin as well as methods for reducing pore appearance or for mattifying the skin, methods and skincare products with even greater mattifying effect and pore appearance reducing effect continue to be in demand. The object of the present invention is therefore to provide a method for reducing skin pore appearance and/or mattifying skin, an aqueous skincare composition, in particular for reducing skin pore appearance and for mattifying skin, and a method for taking care of and/or for treating oily skin.

In view of the demand for new methods and skincare products with greater skin mattifying effect and pore appearance reducing effect, the present inventors tested various compounds to be used in aqueous skincare compositions, and discovered that aqueous compositions containing a particular amount of fusiform particles, which are particles with a "rugby ball" shape, markedly mattified skin and reduced the appearance of pores. The present invention was thus achieved.
The fusiform particles and the manufacture thereof are described in, for example, Patent Document 3.

While compositions containing fusiform particles for cosmetic use have been proposed (Patent Document 1 and Patent Document 2), these compositions are particularly directed to make-up, contains a much higher amount of fusiform particles, and achieves effects such as good transparency and less powdery appearance which are completely different from the effects of the present invention.

Patent Document 1 WO 2010/109545
Patent Document 2 WO 2010/109546
Patent Document 3 JP-A 2003-171465

In the present specification, unless otherwise specified, an aqueous composition according to the present invention is a composition that comprises at least 90 wt% hydrophilic ingredients including water, preferably at least 95 wt% hydrophilic ingredients, and more preferably at least 99 wt% hydrophilic ingredients. While a lipophilic ingredient may also be included in the aqueous composition according to the present invention, the concentration of the lipophilic ingredient is kept to at most 1 wt%. In addition, when the aqueous composition is in the form of an aqueous gel, the composition comprises at least one gelling ingredient in a concentration of at least 0.01 wt%. The term "mattifying" means reducing the shiny appearance of the skin, due in part to the presence of sebum. Moreover, a physiologically acceptable medium is preferably a cosmetically or dermatologically acceptable medium, in particular a cosmetically acceptable medium. For the purpose of the present invention, the term "physiologically acceptable medium" is intended to denote a medium that is suitable for the application of a composition to a keratin material, in particular the skin.
Furthermore, the term "to treat oily skin" means, for example to decrease a shininess score measured by SAMBA (Bossa Nova Technologies) and/or to decrease a sebum score measured by Sebumter (Courage Khazaka). In addition, skin pore appearance reduction means reducing the appearance of pore number and/or size as measured using Dermascore (original device) in combination with Dermapore software.

The term "fusiform" in this specification refers to a "rugby ball" shape that is basically a sphere extended in one direction so that there is a major axis along which a fusiform particle has the largest diameter L₁ which is between approximately 0.05 micrometers and approximately 20 micrometers and a minor axis L₂ perpendicular to the major axis along which the fusiform particle has the smallest diameter which is between approximately 0.03 micrometers and approximately 15 micrometers, L₁/L₂ being between approximately 1.1 and approximately 3.3.

The present invention provides a method for reducing skin pore appearance and/or for mattifying skin, in which an aqueous composition comprising fusiform particles in a physiologically acceptable medium is used. The present invention also provides an aqueous skincare composition comprising at most 5 wt% fusiform particles in a physiologically acceptable medium. The method of the present invention markedly mattifies the skin and reduces the appearance of pores on the skin. Moreover, the skin feels fresh and clean after applying the aqueous skincare composition of the present invention. As such, the method and aqueous skincare composition of the present application are particularly suitable for taking care of and/or for treating oily skin.

Figure 1A shows a bar graph and table comparing shininess scores obtained by using a reference example and an aqueous skincare composition (Example 1) according to the present invention.
Figure 1B shows a bar graph and table comparing sebum scores obtained by using the reference example and the aqueous skincare composition of Figure 1A.
Figure 2A shows a bar graph and table comparing shininess scores obtained by using aqueous skincare compositions of the present invention containing different amounts of fusiform particles (Examples 2, 3 and 4).
Figure 2B shows a bar graph and table comparing sebum scored obtained by using the aqueous skincare compositions of Figure 2A.
Figure 2C shows a graph and table comparing the maximum pore size measured after using the aqueous skincare compositions of Figure 2A.
Figure 3 shows a graph and table comparing mattifying scores over time obtained by using Example 2 and an aqueous skincare composition which contains a low amount of a lipophilic ingredient according to the present invention (Example 5).

Modes for Carrying Out the Present Invention

An embodiment of the present invention provides a method for reducing skin pore appearance and/or for mattifying skin, comprising:
- applying to the skin, an aqueous composition comprising in a physiologically acceptable medium, fusiform particles being made of organosilicone having a crosslinked polysiloxane structure and an average diameter along a major axis L₁ of approximately 0.05 to 20 micrometers, an average diameter along a minor axis L₂ of approximately 0.03 to 15 micrometers, L₁/L₂ being approximately 1.1 to 3.3.
The above method may further comprise the steps of cleansing the skin before applying the composition and allowing the composition to dry after being applied. Moreover, the aqueous composition in the method may be in the form of an aqueous solution or an aqueous gel composition.

In the above embodiment, pore appearance reduction consists of reducing the appearance of pore number and/or size. According to the present invention, the amount of the fusiform particles in the aqueous composition is kept in a range of 0.1 to 10 wt%, preferably 0.1 to 5 wt%, and more preferably 0.5 to 3 wt%. In addition to this particular amount of the fusiform particles, the aqueous composition according to the present invention contains no or a low amount of lipophilic ingredients. These features enable the method of the present application to efficiently mattify the skin, reduce sebum and reduce the appearance of pores without resulting in an unnaturally powdery or slippery finish. In addition, according to the present method, the skin, after applying the aqueous composition, feels fresh and clean.

The organosilicone material having a crosslinked polysiloxane structure used for the fusiform particles preferably comprises, or is composed of, units of formula (I): SiO₂, and of formula (II): R¹SiO_1.5, wherein R¹ denotes an organic group having a carbon atom directly connected to the silicon atom. The organic group can be a reactive organic group or an unreactive organic group and preferably an unreactive organic group.

The organosilicone material having a crosslinked polysiloxane structure preferably comprises first, second and third siloxane units respectively represented by formula (I): SiO₂, formula (II): R¹SiO_1.5 and formula (III): R²R³SiO, wherein R¹, R² and R³ are any one of organic groups, same or different, having a carbon atom directly linked to a silicon atom. R² and R³ may be either a non-reactive organic group or an organic group having no reactive group or a reactive organic group or an organic group having a reactive group, independently. However, at least one of R² and R³ is preferably a reactive organic group or an organic group having a reactive group.

The unreactive organic group mentioned above can be a C₁-C₄ alkyl group, in particular a methyl, ethyl, propyl or butyl group, or a phenyl group and preferably a methyl group.
The reactive organic group can be an epoxy group, a (meth)acryloyloxy group, an alkenyl group, a mercaptoalkyl, aminoalkyl or haloalkyl group, a glyceroxy group, a ureido group or a cyano group, and is preferably an epoxy group, a (meth)acryloyloxy group, an alkenyl group, a mercaptoalkyl or aminoalkyl group. The reactive organic group generally comprises 2 to 6 carbon atoms, in particular 2 to 4 carbon atoms.

As the epoxy group, mention may be made of a 2-glycidoxyethyl group, a 3-glycidoxypropyl group or a 2-(3,4-epoxycyclohexyl)propyl group.
As the (meth)acryloyloxy group, mention may be made of a 3-methacryloyloxypropyl group or a 3-acryloyloxypropyl group.
As the alkenyl group, mention may be made of a vinyl, allyl or isopropenyl group.
As the mercaptoalkyl group, mention may be made of a mercaptopropyl or mercaptoethyl group.

As the aminoalkyl group, mention may be made of a 3-[(2-aminoethyl)amino]propyl group, a 3-aminopropyl group or an N,N-dimethylaminopropyl group. As the haloalkyl group, mention may be made of a 3-chloropropyl group or a trifluoropropyl group. As the glyceroxy group, mention may be made of a 3-glyceroxypropyl group or a 2-glyceroxyethyl group. As the ureido group, mention may be made of a 2-ureidoethyl group. As the cyano group, mention may be made of a cyanopropyl or cyanoethyl group.
Preferably, in the unit of formula (II), R¹ denotes a methyl group.
Advantageously, the organosilicone material comprises the units (I) and (II) according to a unit (I)/unit (II) molar ratio ranging from 30/70 to 50/50, preferably ranging from 35/65 to 45/55.
Also advantageously, the organosilicone material comprises the units (I), (II) and (III) so that the molar ratio of the molar sum of the first siloxane unit (I) and the second unit (II) over the third siloxane unit (III) is between 99:1 to 50:50, more preferably between 90:10 to 60:40, approximately. The molar ratio of the first siloxane unit (I) with respect to the second siloxane unit (II) may preferably be between 23:77 and 40:60, approximately.

The organosilicone particles can in particular be obtained according to a process comprising:
(a) the introduction into an aqueous medium, in the presence of at least one hydrolysis catalyst and optionally of at least one surfactant, of a compound (IV) of formula SiX₄ and of a compound (V) of formula R⁴SiY₃, where X and Y denote, independently of one another, a C₁-C₄ alkoxy group, an alkoxyethoxy group including a C₁-C₄ alkoxy group, a C₂-C₄ acyloxy group, an N,N-dialkylamino group including a C₁-C₄ alkyl group, a hydroxyl group, a halogen atom or a hydrogen atom and R denotes an organic group comprising a carbon atom connected directly to the silicon atom; and
(b) the operation in which the mixture resulting from stage (a) is brought into contact with an aqueous solution including at least one polymerization catalyst and optionally at least one surfactant, at a temperature of between 30 and 85 degree Celsius, for at least two hours.

Stage (a) corresponds to a hydrolysis reaction and stage (b) corresponds to a condensation reaction.
In stage (a), the molar ratio of the compound (IV) to the compound (V) generally ranges from 30/70 to 50/50, advantageously from 35/65 to 45/45, and is preferentially 40/60. The ratio by weight of the water to the total of the compounds (IV) and (V) preferably ranges from 10/90 to 70/30. The order of introduction of the compounds (IV) and (V) generally depends on their rate of hydrolysis. The temperature of the hydrolysis reaction generally ranges from 0 to 40 degree Celsius and usually does not exceed 30 degree Celsius in order to prevent premature condensation of the compounds.
The organosilicone particles can also be obtained according to a process comprising:
(a) the introduction into an aqueous medium, in the presence of at least one hydrolysis catalyst, of a silanol group forming silicon compound (IV) of formula SiX₄, of a silanol group forming silicon compound (V) of formula R⁴SiY₃, and of a silanol group forming silicon compound (VI) of formula R⁵R⁶SiZ₂, at a molar ratio for the silanol group forming silicon compound (IV) and the silanol group forming silicon compound (V): the silanol group forming silicon compound (VI) to be 99:1 to 50:50, preferably 90:10 to 60:40 so that the silanol group forming silicon compounds are hydrolyzed to generate a silanol compound (it is further preferred that the silanol forming silicon compounds of formula (IV) and (V) be at a molar ratio of 23:77 to 40:60); and
(b) causing condensing reaction of the generated silanol compound in an aqueous medium in the presence of at least one hydrolysis catalyst.

With respect to the X, Y and Z groups of the compounds (IV), (V) and (VI):
as the C₁-C₄ alkoxy group, mention may be made of a methoxy or ethoxy group;
as the alkoxyethoxy group including a C₁-C₄ alkoxy group, mention may be made of a methoxyethoxy or butoxyethoxy group;
as the C₂-C₄ acyloxy group, mention may be made of an acetoxy or propionyloxy group;
as the N,N-dialkylamino group including a C₁-C₄ alkyl group, mention may be made of a dimethylamino or diethylamino group; and
as the halogen atom, mention may be made of a chlorine or bromine atom.

Examples of compounds of formula (IV) include tetramethoxysilane, tetraethoxysilane, tetrabutoxysilane, trimethoxyethoxysilane, tributoxy-ethoxysilane, tetraacetoxysilane, tetrapropioxysilane, tetra(dimethylamino)silane, tetra(diethylamino)silane, silanetetraol, chlorosilanetriol, dichlorodisilanol, tetrachlorosilane and chlorotrihydrosilane. The compound of formula (IV) is preferably chosen from tetra-methoxysilane, tetraethoxysilane, tetrabutoxysilane and mixtures thereof.

The compound of formula (IV), after the polymerization reaction, results in the formation of the units of formula (I). The compound of formula (V), after the polymerization reaction, results in the formation of the units of formula (II). The R group in formula (V) has the same definition as the R¹ group in formula (II).

Examples of compounds of formula (V) comprising an unreactive organic group R include methyltrimethoxysilane, ethyltriethoxysilane, propyltributoxysilane, butyltributoxysilane, phenyltri-methoxyethoxysilane, methyltributoxyethoxysilane, methyltriacetoxysilane, methyltripropioxysilane, methyltri(dimethylamino)silane, methyltri(diethyl-amino)silane, methylsilanetriol, methylchlorodisilanol, methyltrichlorosilane and methyltrihydrosilane.

Examples of compounds of formula (V) comprising a reactive organic group R include:
silanes having an epoxy group, such as (3-glycidoxy-propyl)trimethoxysilane, (3-glycidoxypropyl)triethoxy-silane, [2-(3,4-epoxycyclohexyl)ethyl]trimethoxy-silane, (3-glycidoxypropyl)methyldimethoxysilane, (2-glycidoxy-ethyl)methyldimethoxysilane, (3-glycidoxypropyl)di-methylmethoxysilane and (2-glycidoxyethyl)dimethyl-methoxysilane;
silanes having a (meth)acryloyloxy group, such as (3-methacryloyloxypropyl)trimethoxysilane and (3-acryl-oyloxypropyl)trimethoxysilane;
silanes having an alkenyl group, such as vinyltri-methoxysilane, allyltrimethoxysilane and isopropenyltri-methoxysilane;
silanes having a mercapto group, such as mercapto-propyltrimethoxysilane and mercaptoethyltrimethoxy-silane;
silanes having an aminoalkyl group, such as (3-amino-propyl)trimethoxysilane, (3-[(2-aminoethyl)amino]-propyl)trimethoxysilane, (N,N-dimethylaminopropyl)tri-methoxysilane and (N,N-dimethylaminoethyl)trimethoxy-silane;
silanes having a haloalkyl group, such as (3-chloro-propyl)trimethoxysilane and trifluoropropyltrimethoxy-silane;
silanes having a glyceroxy group, such as (3-glyceroxy-propyl)trimethoxysilane and di(3-glyceroxypropyl)di-methoxysilane;
silanes having a ureido group, such as (3-ureido-propyl)trimethoxysilane, (3-ureidopropyl)methyldi-methoxysilane and (3-ureidopropyl)dimethylmethoxy-silane; and
silanes having a cyano group, such as cyanopropyltri-methoxysilane, cyanopropylmethyldimethoxysilane and cyanopropyldimethylmethoxysilane.

The compound of formula (V) comprising a reactive organic group R is preferably chosen from silanes having an epoxy group, silanes having a (meth)acryloyloxy group, silanes having an alkenyl group, silanes having a mercapto group or silanes having an aminoalkyl group.

Examples of compounds (IV) and (V) which are preferred for the implementation of the present invention are respectively tetraethoxysilane and methyltri-methoxysilane.
The hydrolysis and polymerization catalysts may be independently a basic catalyst, such as sodium hydroxide, potassium hydroxide, sodium carbonate, sodium hydrogencarbonate or an amine (such as ammonia, trimethylamine, triethylamine or tetramethyl-ammonium hydroxide), or may be an acidic catalyst chosen from organic acids, such as citric acid, acetic acid, methanesulphonic acid, p-toluenesulphonic acid, dodecylbenzenesulphonic acid and dodecylsulphonic acid, and inorganic acids, such as hydrochloric acid, sulphuric acid or phosphoric acid. In the presence of the catalyst, the surfactant used is preferably a nonionic or anionic surfactant or a mixture of the two. Sodium dodecyl-benzenesulphonate can be used as an anionic surfactant. The end of the hydrolysis is marked by the disappearance of products (IV) and (V), which are insoluble in water, and the production of a homogeneous liquid layer.
The silanol forming silicon compound of formula (VI) results in siloxane unit (III). The group Z in formula (VI) may be selected from the list of groups for group X in formula (IV). R⁵ and R⁶ in formula (VI) may be selected from list of groups for R² and R³ in formula (III).

The catalyst in the condensation stage (b) may be the same catalyst in the hydrolysis stage or another catalyst chosen from those mentioned above.
On conclusion of this process, a suspension of fine organosilicone particles in water is obtained, and the particles can optionally be separated from the medium subsequently. The process described above can thus comprise an additional stage of filtration, for example, on a membrane filter, of the product resulting from stage (b), optionally followed by a stage of centrifuging the filtrate, intended to separate the particles from the liquid medium, and then by a stage of drying the particles. Other separation methods can, of course, be employed.

In a particular embodiment of the present invention, R¹ and at least one of R² and R³ are selected from the group consisting of epoxy groupm, (meth)acryloxy group, alkenyl group, mercaptoalkyl group, aminoalkyl group and organic groups having any one of the preceding groups. In another embodiment of the present invention, the fusiform particles have slits along their major axes.

Another embodiment of the present invention provides an aqueous skincare composition, in particular for reducing skin pore appearance and/or for mattifying skin, comprising in a physiologically acceptable medium, at most 5 wt% fusiform particles, wherein the fusiform particles are made of an organosilicone having a crosslinked polysiloxane structure and have an average diameter along a major axis L₁ of approximately 0.05 to 20 micrometers, an average diameter along a minor axis L₂ of approximately 0.03 to 15 micrometers, L₁/L₂ being approximately 1.1 to 3.3.

In the above embodiment of the present invention, the fusiform particles are preferably present in the aqueous composition at approximately 0.5 to 4 wt%, and preferably at 0.5 to 3 wt%, and more preferably at 1 to 2 wt%. Moreover, the composition is preferably in the form of an aqueous solution or an aqueous gel composition. The fusiform particles are as defined above.

Another embodiment of the present invention provides a method for taking care of and/or for treating oily skin, said method comprising:
- applying to the skin of an individual in need thereof, in particular the skin of the face of the individual, an aqueous composition comprising fusiform particles in an amount as defined above.

The aqueous composition according to the present invention may further comprise at least one compound selected from water, hydrophilic solvents, lipophilic solvents, oils, waxes and pasty fatty substances and mixtures thereof, the lipophilic substances being in an amount of at most 1 wt%. The water may be floral water, such as cornflower water and/or mineral water such as eau de Vittel, eau de Lucase or eau de La Roche Posay and/or spring water. The oils may be chosen from volatile or non-volatile hydrocarbon-based oils of animal, plant or mineral origin, synthetic oils, silicone oils and fluoro oils, and mixtures thereof.

The aqueous composition according to the present invention may further comprise at least one active compound, at least one filler, and/or another cosmetically acceptable ingredient.

The active compound may be selected from Peumus boldus leaf extract, disodium EDTA, Capryloyl salicyclic acid and potassium hydroxide. The filler may be selected from the group consisting of talc, mica, silica, kaolin, powders formed of polyamide, of poly-beta-alanine and of polyethylene, powders formed of tetrafluoro-ethylene polymers, lauryllysine, starch, boron nitride, polymeric hollow microspheres of poly(vinylidene chloride)/acrylonitrile or of acrylic acid copolymers, silicone resin microbeads, particles formed of polyorgano-siloxane elastomers, precipitated calcium carbonate, magnesium carbonate, basic magnesium carbonate, hydroxyapatite, barium sulphate, aluminium oxides, polyurethane powders, composite fillers, hollow silica microspheres, glass or ceramic microcapsules, or metal soaps derived from organic carboxylic acids having from 8 to 22 carbon atoms, preferably from 12 to 18 carbon atoms, for example zinc stearate, magnesium stearate, lithium stearate, zinc laurate and magnesium myristate.

The cosmetically acceptable ingredient may be selected from the group consisting of waxes, preservatives, cosmetic active principles, moisturizing agents, UV screening agents, thickeners, water, surfactants, binders and fragrances.

The composition according to the invention may further comprise at least one other conventional cosmetic ingredient that is compatible with the aqueous composition, and can be chosen from gelling and/or thickening agents, antioxidants, fragrances, preservatives, neutralizing agents, sunscreens, vitamins, moisturizing agents, self-tanning compounds, antiwrinkle active agents, emollients, hydrophilic or lipophilic active principles, agents for combating pollution or free radicals, sequestering agents, film-forming agents, nonelastomeric surfactants, dermo-decontracting active agents, soothing agents, agents which stimulate the synthesis of dermal or epidermal macromolecules and/or which prevent their decomposition, antiglycation agents, agents which combat irritation, desquamating agents, depigmenting, antipigmenting or propigmenting agents, NO-synthase inhibitors, agents which stimulate the proliferation of fibroblasts or keratinocytes and/or the differentiation of keratinocytes, agents which act on the microcirculation, agents which act on the energy metabolism of cells, healing agents, and mixtures thereof.

The aqueous composition according to the present invention may also comprise a mixture of water and of water-miscible organic solvent(s) (miscibility with water of greater than 50 wt% at 25 degree Celsius), for instance monoalcohols containing from 1 to 5 carbon atoms such as ethanol and isopropanol, glycols containing from 2 to 8 carbon atoms such as glycerol, propylene glycol, 1,3-butylene glycol, dipropylene glycol or diethylene glycol, glycol ethers such as mono-, di- or tripropylene glycol (C₁ to C₄)alkyl ethers and mono-, di- or triethylene glycol (C₁ to C₄)alkyl ethers, C₃ to C₄ ketones and C₂ to C₄ aldehydes, and mixtures thereof.

The aqueous phase (water and optionally the water-miscible organic solvent(s)) may also comprise stabilizers, for instance sodium chloride, magnesium dichloride and magnesium sulfate.

Examples

Herebelow, the present invention shall be explained in further detail with examples; however, the present invention is not limited thereto.

(Shininess-Reducing and Sebum-Reducing Effects of NLK-602)
Example 1 and Reference
Example 1 and Reference were prepared according to Table 1.
Table 1

(Shininess Score Measurement)
To evaluate the shininess-reducing effect of NLK-602, pictures of the entire faces of male subjects were taken using SAMBA (Bossa Nova Technologies), and a bare skin shininess score (T₀) was determined for each individual by image processing of the SAMBA pictures using SHIVA software. The subjects were then divided into two groups, Reference was applied to the faces of one group and Example 1 was applied to the faces of the other group. The amount applied to the face of each subject was 2 ml of the example for half of the face, and this amount was used for all of the examples (including Examples 2, 3 and 4 below). The compositions were left for 30 minutes. Shininess scores were determined again at the end of the 30-minute period (T₃₀). The scores at T₃₀ were converted to percentages relative to respective scores at T₀ (T₀ being 100.0%). The results were compared using student's t test to determine whether there was any significant difference between the T₀ and T₃₀ shininess scores.

(Sebum Score Measurement)
To determine the sebum-reducing effect of NLK-602, bare skin sebum scores (T₀) of the foreheads of at least six male subjects were first determined using Sebumeter (Courage-Khazaka). The subjects were then divided into two groups, Reference was applied to the foreheads of one group and Example 1 was applied to the foreheads of the other group. The compositions were left for 30 minutes. Sebum scores were determined again at the end of the 30-minute period (T₃₀). The scores at T₃₀ were converted to percentages relative to respective scores at T₀ (T₀ being 100.0%). The results were compared using student's t test to determine whether there was any significant difference between the T₀ and T₃₀ sebum scores.

The results of the shininess and sebum score measurements are summarized in Figure 1, and clearly indicate a significant decrease in both the shininess score and sebum score with the application of Example 1 containing NLK-602. In contrast, the shininess and sebum scores were not significantly decreased by the application of Reference.

(Effective Concentration Range of NLK-602)
Examples 2, 3 and 4
Next, the shininess- and sebum-reducing effects of NLK-602 were evaluated across a range of concentrations of NLK-602. Examples 2, 3 and 4 were prepared according to Table 2.

Table 2

Shininess scores and sebum scores were measured at T₀ and T₃₀ in the manner described above. The results are respectively summarized in Figure 2A and B, and demonstrate a dose-dependent decrease in the shininess score with increasing concentrations of NLK-602. While 1 wt% NLK-602 did not result in a significant change, 2 wt% and 5 wt% NLK-602 decreased the shininess score significantly. On the other hand, all three concentrations of NLK-602 decreased the sebum score significantly.

(Maximum Pore Size Measurement)
In addition to the shininess and sebum scores, the effects of Examples 2, 3 and 4 on maximum pore size were evaluated. Before application of the compositions, pictures of both cheeks of male subjects were taken using Dermascore (original device by L'Oreal), and the pictures were image processed by Dermapore software to determine the maximum pore size of each individual at T₀ (bare skin). The subjects were divided into three groups and Examples 2, 3 and 4 were applied to the cheeks of subjects in respective groups. The compositions were left for 30 minutes, and maximum pore size was determined again at the end of the 30-minute period (T₃₀). The maximum pore sizes at T₃₀ were expressed as percentages relative to respective pore sizes at T₀ (T₀ being 100.0%). The results were compared using student's t test to determine whether there was any significant difference between the T₀ and T₃₀ maximum pore sizes. The results of the maximum pore size measurement are summarized in Figure 2C. As can be seen from Figure 2C, Examples 2 and 3 both resulted in a significant decrease in the maximum pore size, and Example 4 also exhibited a decrease, though non-significant, in the maximum pore size.

(Inclusion of Lipophilic Ingredient)
While the above examples contained only hydrophilic ingredients, the present invention is not limited thereto. Example 5 was prepared with a lipophilic ingredient, dimethicone, according to Table 3, and compared with Example 2 with respect to their mattifying effects. Mattifying scores were measured as described below.
Table 3

(Mattifying Score Measurement)
Examples 2 and 5 were applied to pieces of contrast paper (Erichsen; Type 24/5), each forming a 50-micrometer layer thereon. The samples were left for 20 minutes, 2 hours, and 6 hours, and intensities of specular reflection light and diffused reflection light were measured by goniophotometer (Murakami) at each time point. Using a BaSO₄ layer as a standard matte surface, an ideal mattifying value was set using the formula below.

Intensity of specular reflection (BaSO₄)/Intensity of diffused reflection (BaSO₄) = 100%

The values obtained using Examples 2 and 5 were then compared to the ideal mattifying value to determine whether the presence of a lipophilic ingredient affected the mattifying effect of NLK-602-containing compositions. The results are summarized in Figure 3. As can be seen from Figure 3, Examples 2 and 5 exhibited similar trends in terms of their mattifying scores across the time points, indicating that a lipophilic ingredient can be included without compromising the desired mattifying effect.

The present invention has been explained with reference to the examples above. As can be seen from the experimental results, the aqueous compositions of the examples exhibited markedly greater mattifying effect and pore minimizing effect than that of the reference. These examples are only exemplifications of specific possibilities, and those skilled in the art will recognize that various modifications are possible, and that such modifications are also covered by the present invention.

Claims

A method for reducing skin pore appearance and/or for mattifying skin, comprising:
applying to the skin, an aqueous composition comprising in a physiologically acceptable medium, fusiform particles being made of an organosilicone having a crosslinked polysiloxane structure and an average diameter along a major axis L₁ of approximately 0.05 to 20 micrometers, an average diameter along a minor axis L₂ of approximately 0.03 to 15 micrometers, L₁/L₂ being approximately 1.1 to 3.3.
The method of claim 1, further comprising the steps of:
cleansing the skin before applying the composition; and
allowing the composition to dry after being applied.
The method according to claim 1 or 2, wherein said aqueous composition is in the form of an aqueous solution or an aqueous gel composition.
The method according to any one of claims 1 to 3, wherein the pore appearance reduction consists of reducing the appearance of pore number and/or size.
The method according to any one of claims 1 to 4, wherein the composition comprise 0.1 to 10 wt%, preferably 0.1 to 5 wt%, and more preferably 0.5 to 3 wt% of said fusiform particles.
The method according to any one of claims 1 to 5, wherein the crosslinked polysiloxane comprises first, second and third siloxane units which are SiO₂, R¹SiO_1.5 and R²R³SiO, respectively, wherein R¹, R² and R³ are any one of organic groups, same or different, having a carbon atom directly linked to a silicon atom.
The method according to claim 6, wherein molar ratio of the molar sum of the first siloxane unit and the second unit over the third siloxane unit is between 99:1 to 50:50, preferably between 90:10 to 60:40, approximately.
The method according to claim 6 or 7, wherein molar ratio of the first siloxane unit with respect to the second siloxane unit is between 23:77 and 40:60, approximately.
The method according to any one of claims 6 to 8, wherein R¹ and at least one of R² and R³ are selected from the group consisting of epoxy group, (meth)acryloxy group, alkenyl group, mercaptoalkyl group, aminoalkyl group and organic groups having any one of preceding groups.
The method according to any one of claims 1 to 9, wherein the fusiform particles have slits along their major axes.
An aqueous skincare composition, in particular for reducing skin pore appearance and/or for mattifying skin, comprising in a physiologically acceptable medium, at most 5 wt% fusiform particles, wherein the fusiform particles are made of an organosilicone having a crosslinked polysiloxane structure and have an average diameter along a major axis L₁ of approximately 0.05 to 20 micrometers, an average diameter along a minor axis L₂ of approximately 0.03 to 15 micrometers, L₁/L₂ being approximately 1.1 to 3.3.
The aqueous composition according to claim 11, wherein the fusiform particles are present at approximately 0.5 to 4 wt%, and preferably at 0.5 to 3 wt%, and more preferably at 1 to 2 wt%.
The aqueous composition according to any one of claims 11 or 12, wherein the composition is in the form of an aqueous solution or an aqueous gel composition.
The aqueous composition according to any one of claims 11 to 13, wherein the fusiform particles are as defined in any one of claims 6 to 10.
A method for taking care of and/or for treating oily skin, said method comprising:
applying to the skin of an individual in need thereof, in particular the skin of the face of the individual, an aqueous composition as defined in any one of claims 1 to 14.