WO2024135301A1

WO2024135301A1 - Composition comprising hyaluronic acid-including hydrophobicized nanoparticles

Info

Publication number: WO2024135301A1
Application number: PCT/JP2023/043204
Authority: WO
Inventors: Rui Niimi; Takahiko KASAI; Tatsushi Isojima
Original assignee: L'oreal
Priority date: 2022-12-19
Filing date: 2023-11-28
Publication date: 2024-06-27

Abstract

The present invention relates to a composition comprising: (a) at least one cationic polymer; (b-1) at least one first anionic polymer selected from hyaluronic acids and derivatives thereof; (b-2) at least one second anionic polymer which is different from the (b-1) first anionic polymer; (c) at least one non-polymeric acid or a salt thereof; (d) at least one optional metal salt; (e) at least one fatty acid; and (f) water, under specific conditions. The composition according to the present invention can be stable, and transparent or translucent. Furthermore, the composition according to the present invention can deliver hyaluronic acids and/or hyaluronic acid derivatives deeper into a keratin substance such as skin.

Description

DESCRIPTION

TITLE OF INVENTION

COMPOSITION COMPRISING HYALURONIC ACID-INCLUDING HYDROPHOBICIZED NANOPARTICLES

TECHNICAL FIELD

The present invention relates to a composition including a nanoparticle including hyaluronic acid or salt(s) thereof, as well as a cosmetic process using the composition,

BACKGROUND ART

Hyaluronic acid is a predominant glucosaminoglycan found in the skin. Thus, the fibroblasts synthesize predominantly collagens, matrix glycoproteins other than collagens (fibronectin, laminin), proteoglycans and elastin. The keratinocytes, for their part, synthesize predominantly sulfated glycosaminoglycans and hyaluronic acid. Hyaluronic acid is also called hyaluronan (HA).

Hyaluronic acid is present in a free state in the epidermis and in the dermis and is responsible for turgescence of the skin. This polysaccharide can in fact retain a large volume of water, corresponding to up to 1000 times its weight. In this sense, hyaluronic acid plays an important role in increasing the amounts of water bound in the tissue, and also in the mechanical properties of the skin and in wrinkle formation.

Hyaluronic acid has been widely used as a cosmetic ingredient due to its high moisturizing effects.

JP-A-2014-114272 discloses a complex particle including hyaluronic acid, chitosan, and an anionic polymer other than hyaluronic acid.

DISCLOSURE OF INVENTION

It has been found that a complex particle including hyaluronic acid, such as that disclosed in JP-A-2014-114272, sometimes has difficulty in penetrating into a keratin substance such as skin.

Further, in some cases, a composition including such a complex particle is required to be stable without causing precipitations, and transparent or translucent with a lower level of turbidity. Furthermore, it is preferable for the complex particle to be small such that it has a nano-meter size (less than 1,000 nm), in terms of the penetration ability into a keratin substance such as skin.

Thus, an objective of the present invention is to provide a stable, transparent or translucent composition, comprising a hyaluronic acid-including nanoparticle, which could deliver hyaluronic acid deeper into a keratin substance such as skin.

The above objective of the present invention can be achieved by a composition, preferably a cosmetic composition, and more preferably a skin cosmetic composition, comprising nanoparticles comprising:

(a) at least one cationic polymer;

(b-1) at least one first anionic polymer selected from hyaluronic acids and derivatives thereof;

(b-2) at least one second anionic polymer which is different from the (b-1) first anionic polymer;

(c) at least one non-polymeric acid or a salt thereof;

(d) at least one optional metal salt; and

(e) at least one fatty acid, and

(f) water, wherein the amount of the nanoparticles is from 0.01% to 0.58% by weight, preferably from 0.05% to 0.57% by weight, and more preferably from 0.1% to 0.56% by weight, relative to the total weight of the composition, the weight ratio of the amount of the (a) cationic polymer(s) relative to the total weight of the nanoparticles is from 0.06 to 0.25, the weight ratio of the amount of the (b-2) second anionic polymer relative to the total weight of the nanoparticles is 0.26 or more, the weight ratio of the amount of the (c) non-polymeric acid(s) or salt(s) thereof relative to the total weight of the nanoparticles is 0.03 or more, the weight ratio of the amount of the (d) optional metal salt(s) relative to the total weight of the nanoparticles is 0.30 or less, and the weight ratio of the amount of the (e) fatty acid(s) relative to the total weight of the nanoparticles is 0.001 or more.

The (a) cationic polymer may have at least one positively chargeable and/or positively charged moiety selected from the group consisting of a primary, secondary or tertiary amino group, a quaternary ammonium group, a guanidine group, a biguanide group, an imidazole group, an imino group, and a pyridyl group.

The (a) cationic polymer may be selected from the group consisting of cyclopolymers of alkyldiallylamine and cyclopolymers of dialkyldiallylammonium such as (co)polydiallyldialkyl ammonium chloride, (co)polyamines such as chitosans and (co)polylysines, cationic (co)polyaminoacids such as collagen and arginine/lysine polypeptide, cationic cellulose polymers, and salts thereof.

The weight ratio of the amount of the (a) cationic polymer(s) relative to the total weight of the nanoparticles in the composition according to the present invention may be from 0.06 to 0.24, preferably from 0.07 to 0.22, and more preferably from 0,08 to 0.20.

The (b-1) first anionic polymer may have a molecular weight of 2,000 kDa or less, preferably 1,000 kDa or less, and more preferably 100 kDa or less.

The weight ratio of the amount of the (b-1) first anionic polymer(s) relative to the total weight of the nanoparticles in the composition according to the present invention may be from 0.01 to 0.8, preferably from 0.02 to 0.7, and more preferably from 0,03 to 0.6.

The (b-2) second anionic polymer may be selected from the group consisting of carrageenan, pectin and a mixture thereof. The weight ratio of the amount of the (b-2) second anionic polymer(s) relative to the total weight of the nanoparticles in the composition according to the present invention may be from 0.26 to 0.9, preferably from 0,28 to 0.8, and more preferably from 0.30 to 0.7.

The (c) non-polymeric acid or salt(s) thereof may be selected from the group consisting of phytic acid, citric acid, lactic acid and a mixture thereof.

The weight ratio of the amount of the (c) non-polymeric acid(s) or salt(s) thereof relative to the total weight of the nanoparticles in the composition according the present invention may be from 0.03 to 0.6, preferably from 0.035 to 0.5, and more preferably from 0.04 to 0.4.

The (d) optional metal salt may be selected from polyvalent metal salts, preferably divalent metal salts, more preferably calcium salts such as calcium chloride and calcium pyrrolidone carboxylate, and magnesium salts such as magnesium chloride.

The weight ratio of the amount of the (d) optional metal salt relative to the total weight of the nanoparticles in the composition according to the present invention may be from 0.001 to 0.30, preferably from 0.005 to 0.25, and more preferably from 0.01 to 0,20.

The (e) fatty acid may be selected from C₄-C₂₂, preferably C₆-C₂₀, more preferably C₈-C₁₈ saturated and unsaturated, linear or branched fatty acids.

The weight ratio of the amount of the (e) fatty acid relative to the total weight of the nanoparticles in the composition according to the present invention may be from 0.001 to 0.4, preferably from 0.002 to 0.3, and more preferably from 0.003 to 0.2.

The amount of the (f) water in the composition according to the present invention may be from 50% to 95% by weight, preferably from 60% to 90% by weight, and more preferably from 70% to 85% by weight, relative to the total weight of the composition.

The present invention also relates to a cosmetic process for a keratin substance such as skin, comprising: applying to the keratin substance the composition according to the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION

After diligent research, the inventors have discovered that it is possible to provide a stable, transparent or translucent composition, comprising a hyaluronic acid-including nanoparticle, which could deliver hyaluronic acid deeper into a keratin substance such as skin.

Thus, the composition according to the present invention which is preferably a cosmetic composition, and more preferably a skin cosmetic composition, comprises nanoparticles comprising:

(a) at least one cationic polymer;

(c) at least one non-polymeric acid or a salt thereof; (d) at least one optional metal salt; and

(e) at least one fatty acid, and

(f) water, wherein the amount of the nanoparticles is from 0.01% to 0.58% by weight, preferably from 0.05% to 0.57% by weight, and more preferably from 0.1% to 0.56% by weight, relative to the total weight of the composition, the weight ratio of the amount of the (a) cationic polymer(s) relative to the total weight of the nanoparticles is from 0.06 to 0.25, the weight ratio of the amount of the (b-2) second anionic polymer relative to the total weight of the nanoparticles is 0,26 or more, the weight ratio of the amount of the (c) non-polymeric acid(s) or salt(s) thereof relative to the total weight of the nanoparticles is 0.03 or more, the weight ratio of the amount of the (d) optional metal salt(s) relative to the total weight of the nanoparticles is 0.30 or less, and the weight ratio of the amount of the (e) fatty acid(s) relative to the total weight of the nanoparticles is 0.001 or more.

The term “nanoparticle” means a particle with a size or diameter of less than 1 ,000 nm. The size or diameter of the nanoparticle can be measured by a dynamic light scattering method. This particle diameter may be based on a volume average diameter.

The composition according to the present invention can include nanoparticles comprising the (a) cationic polymer(s), the (b-1) first anionic polymer(s), the (b-2) second anionic polymer(s), the (c) non-polymeric acid(s) or salt(s) thereof, the (d) optional metal salt(s), and the (e) fatty acid(s). The (b-1) first anionic polymer is selected from hyaluronic acids and derivatives thereof. Thus, the nanoparticles include at least one hyaluronic acid and/or at least one hyaluronic acid derivative.

The nanoparticles can be polyion complex particles which are formed by polyion complex(es).

The (a) cationic polymer can be hydrophobicized by the (e) fatty acid. The cationic group such as a quaternary ammonium group in the (a) cationic polymer can ionically interact with the carboxylic group, which is anionic, of the (f) fatty acid. As the (e) fatty acid has a hydrophobic moiety, the (a) cationic polymer can be ionically hydrophobicized and can have sufficient hydrophobicity. Thus, the nanoparticles including the (a) cationic polymer can be hydrophobicized by the (e) fatty acid. Surprisingly, the hydrophobicized nanoparticles can penetrate into deeper into a keratin substance such as skin, as compared to non- hydrophobicized nanoparticles.

The nanoparticles can exert cosmetic effects based on the hyaluronic acid and/or hyaluronic acid derivative. Thus, the composition according to the present invention can provide cosmetic effects, such as moisturizing effects, based on the hyaluronic acid and/or hyaluronic acid derivative.

The composition according to the present invention can be stable, and transparent or translucent. Furthermore, the composition according to the present invention can include hyaluronic acid-including nanoparticles with enhanced penetration capability into a keratin substance such as skin, Thus, the composition according to the present invention can deliver hyaluronic acids and/or hyaluronic acid derivatives deeper into a keratin substance such as skin.

Hereinafter, the composition, process, and the like according to the present invention will be explained in a more detailed manner.

[Nanoparticle]

The composition according to the present invention includes nanoparticles including:

(a) at least one cationic polymer,

(c) at least one non-polymeric acid or a salt thereof;

(d) at least one optional metal salt; and

(e) at least one fatty acid.

The above ingredients (a) to (e), in particular mainly the ingredients (a), (b-1), (b-2) and (c) can form a polyion complex. The polyion complex can be in the form of a nanoparticle.

Two or more different types of nanoparticles may be present in combination. Thus, a single type of a nanoparticle or a combination of different types of nanoparticles may be present in the composition according to the present invention.

The size or diameter of the nanoparticle may be from 5 nm to 500 nrn, preferably from 10 nm to 400 nm, more preferably from 20 nm to 300 nm, and even more preferably from 30 nm to 200 mu. The size of diameter may be a volume-based average size or diameter.

The amount of the nanoparticles in the composition according to the present invention is from 0.01% to 0.58% by weight, preferably from 0.05% to 0.57% by weight, more preferably from 0.1% to 0.56% by weight, and even more preferably from 0.2% to 0.55% by weight, relative to the total weight of the composition.

(Cationic Polymer)

The composition according to the present invention includes (a) at least one cationic polymer. Two or more different types of cationic polymers may be used in combination. Thus, a single type of a cationic polymer or a combination of different types of cationic polymers may be used.

The (a) cationic polymer has a positive charge density. The charge density of the (a) cationic polymer may be from 0.01 meq/g to 20 meq/g, preferably from 0.05 to 15 meq/g, and more preferably from 0.1 to 10 meq/g.

It may be preferable that the molecular weight of the (a) cationic polymer be 500 or more, preferably 1,000 or more, more preferably 2,000 or more, and even more preferably 3,000 or more. Unless otherwise defined in the descriptions, “molecular weight” means a weight average molecular weight. The (a) cationic polymer may have at least one positively chargeable and/or positively charged moiety selected from the group consisting of a primary, secondary or tertiary amino group, a quaternary ammonium group, a guanidine group, a biguanide group, an imidazole group, an imino group, and a pyridyl group. The term “(primary) amino group” here means an -NH₂ group.

The (a) cationic polymer may be a homopolymer or a copolymer. The term “copolymer” is understood to mean both copolymers obtained from two kinds of monomers and those obtained from more than two kinds of monomers, such as terpolymers obtained from three kinds of monomers.

The (a) cationic polymer may be selected from natural and synthetic cationic polymers. Nonlimiting examples of the (a) cationic polymer are as follows.

(1) Homopolymers and copolymers derived from acrylic or methacrylic esters and amides and comprising at least one unit chosen from units of the following formulas:

wherein:

R₁ and R₂, which may be identical or different, are chosen from hydrogen and alkyl groups comprising from 1 to 6 carbon atoms, for instance, methyl and ethyl groups;

R₃, which may be identical or different, is chosen from hydrogen and CH₃; the symbols A, which may be identical or different, are chosen from linear or branched alkyl groups comprising from 1 to 6 carbon atoms, for example, from 2 to 3 carbon atoms, and hydroxyalkyl groups comprising from 1 to 4 carbon atoms; R₄, R₅, and R₆, which may be identical or different, are chosen from alkyl groups comprising from 1 to 18 carbon atoms and benzyl groups, and in at least one embodiment, alkyl groups comprising from 1 to 6 carbon atoms; and

X is an anion derived from an inorganic or organic acid, such as methosulphate anions and halides, for instance chloride and bromide.

The copolymers of family (1) above may also comprise at least one unit derived from comonomers which may be chosen from acrylamides, methacrylamides, diacetone acrylamides, acrylamides and methacrylamides substituted on the nitrogen atom with (C₁-C₄) lower alkyl groups, groups derived from acrylic or methacrylic acids and esters thereof, vinyllactams such as vinylpyrrolidone and vinylcaprolactam, and vinyl esters.

Examples of copolymers of family (1) include, but are not limited to: copolymers of acrylamide and of dimethylaminoethyl methacrylate quaternized with dimethyl sulphate or with a dimethyl halide, copolymers of acrylamide and of methacryloyloxyethyltrimethylammonium chloride described, for example, in European Patent Application No. 0 080 976, copolymers of acrylamide and of methacryloyloxyethyltrimethylammonium metho sulphate, quaternized or nonquaternized vinylpyrrolidone/dialkylaminoalkyl acrylate or methacrylate copolymers, described, for example, in French Patent Nos. 2 077 143 and 2 393 573, dimethylaminoethyl methacrylate/vinylcaprolactam/vinylpyrrolidone terpolymers, vinylpyrrolidone/methacrylamidopropyldimethylamine copolymers, quaternized vinylpyrrolidone/dimethylaminopropylmethacrylamide copolymers, and crosslinked methacryloyloxy(C₁-C₄)alkyltri(C₁-C₄)alkyla monium salt polymers such as the polymers obtained by homopolymerization of dimethylaminoethyl methacrylate quaternized with methyl chloride, or by copolymerization of acrylamide with dimethylaminoethyl methacrylate quaternized with methyl chloride, the homopolymerization or copolymerization being followed by crosslinking with a compound containing an olefinic unsaturation, for example, methylenebisacrylamide.

(2) Cationic cellulose polymers such as cellulose ether derivatives comprising one or more quaternary ammonium groups described, for example, in French Patent No, 1 492 597, such as the polymers sold under the names "JR" (JR 400, JR 125, JR 30M) or "LR" (LR 400, LR 30M) by the company Union Carbide Corporation. These polymers are also defined in the CTFA dictionary as quaternary ammoniums of hydroxyethylcellulose that have reacted with an epoxide substituted with a trimethylammonium group.

It is preferable that the cationic cellulose polymers have at least one quaternary ammonium group, preferably a quaternary trialkyl ammonium group, and more preferably a quaternary trimethyl ammonium group.

The quaternary ammonium group may be present in a quaternary ammonium group- containing group which may be represented by the following chemical formula (I):

wherein each of R₁ and R₂ denotes a C₁-C₃ alkyl group, preferably a methyl or ethyl group, and more preferably a methyl group,

R₃ denotes a C₁-C₂₄ alkyl group, preferably a methyl or ethyl group, and more preferably methyl group,

X- denotes an anion, preferably a halide, and more preferably a chloride, n denotes an integer from 0-30, preferably 0-10, and more preferably 0, and R₄ denotes a C₁-C₄ alkylene group, preferably an ethylene or propylene group.

The leftmost ether bond (-O-) in the above chemical formula (I) can attach to the sugar ring of the polysaccharide.

It is preferable that the quaternary ammonium group-containing group be -O-CH₂-CH(OH)- CH₂-N⁺(CH₃)3.

(3) Cationic cellulose polymers such as cellulose copolymers and cellulose derivatives grafted with a water-soluble monomer of quaternary ammonium, and described, for example, in U.S. Pat. No. 4,131,576, such as hydroxyalkylcelluloses, for instance, hydroxymethyl-, hydroxyethyl-, and hydroxypropylcelluloses grafted, for example, with a salt chosen from methacryloylethyltrimethylammonium, methacrylamidopropyltrimethylammonium, and dimethyldiallylammonium salts.

Commercial products corresponding to these polymers include, for example, the products sold under the name "Celquat® L 200" and "Celquat® H 100" by the company National Starch.

(4) Non-cellulose-based cationic polysaccharides described in U.S. Pat. Nos. 3,589,578 and 4,031,307, such as guar gums comprising cationic trialkylammonium groups, cationic hyaluronic acid, and dextran hydroxypropyl trimonium chloride. Guar gums modified with a salt, for example the chloride, of 2,3 -epoxypropyltrimethylammonium (guar hydroxypropyltrimonium chloride) may also be used.

Such products are sold, for instance, under the trade names JAGUAR® C13 S, JAGUAR® Cl 5, JAGUAR® Cl 7, and JAGUAR® Cl 62 by the company MEYHALL.

(5) Polymers comprising piperazinyl units and divalent alkylene or hydroxyalkylene groups comprising straight or branched chains, optionally interrupted with at least one entity chosen from oxygen, sulphur, nitrogen, aromatic rings, and heterocyclic rings, and also the oxidation and/or quaternization products of these polymers. Such polymers are described, for example, in French Patent Nos. 2 162 025 and 2 280 361.

(6) Water-soluble polyamino amides prepared, for example, by polycondensation of an acidic compound with a polyamine; these polyamino amides possibly being crosslinked with an entity chosen from epihalohydrins; diepoxides; dianhydrides; unsaturated dianhydrides; bisunsaturated derivatives; bishalohydrins; bisazetidiniums; bishaloacyidiamines; bisalkyl halides; oligomers resulting from the reaction of a difunctional compound which is reactive with an entity chosen from bishalohydrins, bisazetidiniums, bishaloacyidiamines, bisalkyl halides, epihalohydrins, diepoxides, and bisunsaturated derivatives; the crosslinking agent being used in an amount ranging from 0.025 to 0.35 mol per amine group of the polyamino amide; these polyamino amides optionally being alkylated or, if they comprise at least one tertiary amine function, they may be quaternized. Such polymers are described, for example, in French Patent Nos. 2 252 840 and 2 368 508. (7) Polyamino amide derivatives resulting from the condensation of polyalkylene polyamines with polycarboxylic acids, followed by alkylation with difunctional agents, for example, adipic acid/dialkylaminohydroxyalkyldialkylenetriamine polymers in which the alkyl group comprises from 1 to 4 carbon atoms, such as methyl, ethyl, and propyl groups, and the alkylene group comprises from 1 to 4 carbon atoms, such as an ethylene group. Such polymers are described, for instance, in French Patent No. 1 583 363. In at least one embodiment, these derivatives may be chosen from adipic acid/dimethylaminohydroxypropyldiethylenetriamine polymers.

(8) Polymers obtained by reaction of a polyalkylene polyamine comprising two primary amine groups and at least one secondary amine group, with a dicarboxylic acid chosen from diglycolic acid and saturated aliphatic dicarboxylic acids comprising from 3 to 8 carbon atoms. The molar ratio of the polyalkylene polyamine to the dicarboxylic acid may range from 0.8:1 to 1.4:1; the polyamino amide resulting therefrom being reacted with epichlorohydrin in a molar ratio of epichlorohydrin relative to the secondary amine group of the polyamino amide ranging from 0.5:1 to 1.8:1. Such polymers are described, for example, in U.S. Pat. Nos. 3,227,615 and 2,961,347.

(9) Cyclopolymers of alkyldiallylamine and cyclopolymers of dialkyldiallyl-ammonium, such as homopolymers and copolymers comprising, as the main constituent of the chain, at least one unit chosen from units of formulas (la) and (lb):

wherein: k and t, which may be identical or different, are equal to 0 or 1, the sum k+t being equal to 1;

R12 is chosen from hydrogen and methyl groups; R₁₀ and Rii, which may be identical or different, are chosen from alkyl groups comprising from 1 to 6 carbon atoms, hydroxyalkyl groups in which the alkyl group comprises, for example, from 1 to 5 carbon atoms, and lower (C₁-C₄)amidoalkyl groups, or R₁₀ and R₁₁ may form, together with the nitrogen atom to which they are attached, heterocyclic groups such as piperidinyl and morpholinyl; and

Y' is an anion such as bromide, chloride, acetate, borate, citrate, tartrate, bisulphate, bisulphite, sulphate, and phosphate. These polymers are described, for example, in French , Patent No. 2 080 759 and in its Certificate of Addition 2 190 406.

In one embodiment, R₁₀ and R₁₁, which may be identical or different, are chosen from alkyl groups comprising from 1 to 4 carbon atoms.

Examples of such polymers include, but are not limited to, (co)polydially Idialkyl ammonium chloride such as the dimethyidiallylammonium chloride homopolymer sold under the name "MERQUAT® 100" by the company CALGON (and its homologues of low weight-average molecular mass) and the copolymers of diallyldimethylammonium chloride and of acrylamide sold under the name "MERQUAT® 550".

Quaternary diammonium polymers comprising at least one repeating unit of formula (II):

wherein: R₁₃, R₁₄, RIS, and Ri6, which may be identical or different, are chosen from aliphatic, alicyclic, and arylaliphatic groups comprising from 1 to 20 carbon atoms and lower hydroxyalkyl aliphatic groups, or alternatively R₁₃, R₁₄, Ris, and Ri6 may form, together or separately, with the nitrogen atoms to which they are attached, heterocycles optionally comprising a second heteroatom other than nitrogen, or alternatively R₁₃, R₁₄, R₁₅, and R₁₆, which may be identical or different, are chosen from linear or branched C₁-C₆ alkyl groups substituted with at least one group chosen from nitrile groups, ester groups, acyl groups, amide groups, -CO-O-R₁₇-E groups, and -CO-NH-R₁₇-E groups, wherein R₁₇ is an alkylene group and E is a quaternary ammonium group;

Ai and B i , which may be identical or different, are chosen from polymethylene groups comprising from 2 to 20 carbon atoms, which may be linear or branched, saturated or unsaturated, and which may comprise, linked or intercalated in the main chain, at least one entity chosen from aromatic rings, oxygen, sulphur, sulphoxide groups, sulphone groups, disulphide groups, amino groups, alkylamino groups, hydroxyl groups, quaternary ammonium groups, ureido groups, amide groups, and ester groups, and

X" is an anion derived from an inorganic or organic acid;

Ai, R₁₃, and Ris may form, together with the two nitrogen atoms to which they are attached, a piperazine ring; if Ai is chosen from linear or branched, saturated or unsaturated alkylene or hydroxyalkylene groups, Bi may be chosen from:

-(CH₂)_n-CO-E'-OC-(CH₂)_n- wherein E' is chosen from: a) glycol residues of formula -O-Z-O-, wherein Z is chosen from linear or branched hydrocarbon-based groups and groups of the following formulas:

-(CH₂-CH₂-O)_X-CH₂-CH₂-

- [CH₂-CH(CH₃)-O]_y-CH₂-CH(CH₃)- wherein x and y, which may be identical or different, are chosen from integers ranging from 1 to 4, which represent a defined and unique degree of polymerization, and numbers ranging from 1 to 4, which represent an average degree of polymerization; b) bis-secondary diamine residue such as piperazine derivatives; c) bis-primary diamine residues of formula -NH-Y-NH-, wherein Y is chosen from linear or branched hydrocarbon-based groups and the divalent group -CH₂-CH₂-S-S-CH₂-CH_2-; and d) ureylene groups of formula -NH-CO-NH-.

In at least one embodiment, X' is an anion such as chloride or bromide.

Polymers of this type are described, for example, in French Patent Nos. 2 320 330; 2 270 846; 2 316 271 ; 2 336 434; and 2 413 907 and U.S. Pat. Nos. 2,273,780; 2,375,853; 2,388,614; 2,454,547; 3,206,462; 2,261,002; 2,271,378; 3,874,870; 4,001,432; 3,929,990; 3,966,904;

4,005,193; 4,025,617; 4,025,627; 4,025,653; 4,026,945; and 4,027,020.

Non-limiting examples of such polymers include those comprising at least one repeating unit of formula (III):

wherein R₁₃, R₁₄, R₁₅, and R₁₆, which may be identical or different, are chosen from alkyl and hydroxyalkyl groups comprising from 1 to 4 carbon atoms, n and p, which may be identical or different, are integers ranging from 2 to 20, and X" is an anion derived from an inorganic or organic acid.

(11) Poly quaternary ammonium polymers comprising units of formula (IV):

wherein:

R₁₈, R₁₉, R₂₀, and R₂₁, which may be identical or different, are chosen from hydrogen, methyl groups, ethyl groups, propyl groups, P-hydroxyethyl groups, P-hydroxypropyl groups, -CH₂CH₂(OCH₂CH₂)_POH groups, wherein p is chosen from integers ranging from 0 to 6, with the proviso that R₁₈, R₁₉, R₂₀, and R₂₁ are not simultaneously hydrogen, r and s, which may be identical or different, are chosen from integers ranging from 1 to 6, q is chosen from integers ranging from 0 to 34, X" is an anion such as a halide, and

A is chosen from radicals of dihalides and -CH₂-CH₂-O-CH₂-CH₂-.

Such compounds are described, for instance, in European Patent Application No. 0 122 324.

(12) Quaternary polymers of vinylpyrrolidone and of vinylimidazole.

Other examples of suitable cationic polymers include, but are not limited to, cationic proteins and cationic protein hydrolysates, polyalkyleneimines, such as polyethyleneimines, polymers comprising units chosen from vinylpyridine and vinylpyridinium units, condensates of polyamines and of epichlorohydrin, quaternary polyureylenes, and chitin derivatives.

According to one embodiment of the present invention, the (a) at least one cationic polymer is chosen from cellulose ether derivatives comprising quaternary ammonium groups, such as the products sold under the name "JR 400" by the company UNION CARBIDE CORPORATION, cationic cyclopolymers, for instance, the homo-polymers and copolymers of dimethyldiallylammonium chloride sold under the names MERQUAT® 100, MERQUAT® 550, and MERQUAT® S by the company CALGON, guar gums modified with a 2,3 -epoxypropyltrimethylammonium salt, and quaternary polymers of vinylpyrrolidone and of vinylimidazole.

(13) Polyamines

As the (a) cationic polymer, it is also possible to use (co)polyamines, which may be homopolymers or copolymers, with a plurality of amino groups. The amino group may be a primary, secondary, tertiary or quaternary amino group. The amino group may be present in a polymer backbone or a pendent group, if present, of the (co)polyamines.

As an example of the (co)polyamines, mention may be made of chitosans, (co)polyallylamines, (co)polyvinylamines, (co)polyanilines, (co)polyvinylimidazoles, (co)polydimethylaminoethylenemethacrylates, (co)polyvinylpyridines such as (co)poly-l- methyl-2-vinylpyridines, (co)polyimines such as (co) polyethyleneimines, (co)polypyridines such as (co)poly(quaternary pyridines), (co)polybiguanides such as (co)polyaminopropyl biguanides, (co)polylysines, (co)polyornithines, (co)polyarginines, (co)polyhistidines, aminodextrans, aminocelluloses, amino(co)polyvinylacetals, and salts thereof.

As the (co)polyamines, it is preferable to use (co)polylysines. Polylysine is well known. Polylysine can be a natural homopolymer of L-lysine that can be produced by bacterial fermentation. For example, polylysine can be s-Poly-L-lysine, typically used as a natural preservative in food products. Polylysine is a polyelectrolyte which is soluble in polar solvents such as water, propylene glycol and glycerol, Polylysine is commercially available in various forms, such as poly D-lysine and poly L-lysine. Polylysine can be in salt and/or solution form.

Arginine/lysine polypeptide may also be used. (14) Cationic Polyaminoacids

As the (a) cationic polymer, it may be possible use cationic polyaminoacids, which may be cationic homopolymers or copolymers, with a plurality of amino groups and carboxyl groups. The amino group may be a primary, secondary, tertiary or quaternary amino group. The amino group may be present in a polymer backbone or a pendent group, if present, of the cationic polyaminoacids. The carboxyl group may be present in a pendent group, if present, of the cationic polyaminoacids.

As examples of the cationic polyaminoacids, mention may be made of cationized collagen, cationized gelatin, steardimonium hydroxypropyl hydrolyzed wheat protein, cocodimonium hydroxypropyl hydrolyzed wheat protein, hydroxypropyltrimonium hydrolyzed conchiolin protein, steardimonium hydroxypropyl hydrolyzed soy protein, hydroxypropyltrimonium hydrolyzed soy protein, cocodimonium hydroxypropyl hydrolyzed soy protein, and the like.

(15) Cationic Starches

As the (a) cationic polymer, mention may also be made of cationic starches.

As examples of the cationic starches, mention may be made of starches modified with a 2,3- epoxypropyltrimethylammonium salt (e.g. chloride), such as the product known as starch hydroxypropyltrimonium chloride according to the INCI nomenclature and sold under the name SENSOMER C1-50 from Ondeo or Pencare™ DP 1015 from Ingredion,

(16) Cationic Gum

As the (a) cationic polymer, mention may also be made of cationic gums.

The gums may be, for example, selected from the group consisting of cassia gum, karaya gum, konjac gum, gum tragacanth, tara gum, acacia gum and gum arabic.

Examples of cationic gums include cationic poly galactomannan derivatives such as guar gum derivatives and cassia gum derivatives, e.g., CTFA: Guar Hydroxypropyltrimonium Chloride, Hydroxypropyl Guar Hydroxypropyltrimonium Chloride, and Cassia Hydroxypropyltrimonium Chloride. Guar hydroxypropyltrimonium chloride is commercially available under the Jaguar™ trade name series from Rhodia Inc. and the N-Hance trade name series from Ashland Inc. Cassia Hydroxypropyltrimonium Chloride is commercially available under the Sensomer™ CT-250 and Sensomer™ CT-400 trademarks from Lubrizol Advanced Materials, Inc. or the ClearHance™ from Ashland Inc.

The following descriptions relate to preferable embodiments of the (a) cationic polymer.

It may be preferable that the (a) cationic polymer be selected from the group consisting of cyclopolymers of alkyldiallylamine and cyclopolymers of dialkyldiallylammonium such as (co)polydiallyldialkyl ammonium chloride, (co)polyamines such as chitosans and (co)polylysines, cationic (co)polyaminoacids such as cationized collagen and arginine/lysine polypeptide, cationic cellulose polymers, and salts thereof.

It may be more preferable that the (a) cationic polymer be selected from the group consisting of polylysines such as poly-a-lysine and poly-8-lysine, arginine/lysine polypeptide, polyquaternium-4, polyquaternium-10, polyquaternium-24, polyquaternium-67, starch hydroxypropyl trimonium chloride, cassia hydroxypropyltrimonium chloride, chitosans such as chitosan, and a mixture thereof.

It may be even more preferable that the (a) cationic polymer be selected from polylysines such as poly-a-lysine and poly-ε-lysine, arginine/lysine polypeptide, chitosans such as chitosan, and a mixture thereof.

The weight ratio of the amount of the (a) cationic polymer(s) relative to the total weight of the nanoparticles in the composition according to the present invention is from 0.06 to 0,25.

The weight ratio of the amount of the (a) cationic polymer(s) relative to the total weight of the nanoparticles in the composition according to the present invention may be from 0.06 to 0.24, preferably from 0.07 to 0.22, and more preferably from 0.08 to 0.20.

(Anionic Polymer)

The composition according to the present invention includes:

(b-1) at least one first anionic polymer selected from hyaluronic acids and derivatives thereof; and

(b-2) at least one second anionic polymer which is different from the (b-1) first anionic polymer.

Two or more different types of anionic polymers may be used in combination for each of the (b-1) first anionic polymer and the (b-2) second anionic polymer. Thus, a single type of an anionic polymer or a combination of different types of anionic polymers may be used for each of the (b-1) first anionic polymer and the (b-2) second anionic polymer,

The (b-1) first anionic polymer and the (b-2) second anionic polymer have a negative charge density. The charge density of each of the (b-1) first anionic polymer and the (b-2) second anionic polymer may be from 0.1 meq/g to 20 meq/g, preferably from 1 to 15 meq/g, and more preferably from 4 to 10 meq/g.

First Anionic Polymer:

According to the present invention, the (b-1) first anionic polymer is selected from hyaluronic acids and derivatives thereof.

Hyaluronic acid can be represented by the following chemical formula.

In the context of the present invention, the term "hyaluronic acid" covers in particular the basic unit of hyaluronic acid of formula:

It is the smallest fraction of hyaluronic acid comprising a disaccharide dimer, namely D- glucuronic acid and N-acetylglucosamine.

The term "hyaluronic acid and derivatives thereof also comprises, in the context of the present invention, a linear polymer comprising the polymeric unit described above, linked together in the chain via alternating β(1 ,4) and β( 1 ,3) glycosidic linkages, having a molecular weight (MW) that can range between 380 and 13,000,000 daltons. Unless otherwise defined in the descriptions, “molecular weight” means a weight average molecular weight. This molecular weight depends in large part on the source from which the hyaluronic acid is obtained and/or on the preparation methods.

The term "hyaluronic acid and derivatives thereof' also comprises, in the context of the present invention, hyaluronic acid salts. As the salts, mention may be made of alkaline metal salts such as sodium salts and potassium salts, alkaline earth metal salts such as magnesium salts, ammonium salts, and mixtures thereof.

In the natural state, hyaluronic acid is present in pericellular gels, in the base substance of the connective tissues of vertebrate organs such as the dermis and epithelial tissues, and in particular in the epidermis, in the synovial fluid of the joints, in the vitreous humor, in the human umbilical cord and in the crista galli apophysis.

Thus, the term "hyaluronic acid and derivatives thereof comprises all the fractions or subunits of hyaluronic acid having a molecular weight in particular within the molecular weight range mentioned above.

In the context of the present invention, hyaluronic acid fractions which do not have an inflammatory activity are preferably used.

By way of illustration of the various hyaluronic acid fractions, reference may be made to the document "Hyaluronan fragments: an information-rich system", R. Stern et al., European Journal of Cell Biology 58 (2006) 699-715, which reviews the listed biological activities of hyaluronic acid according to its molecular weight.

The molecular weight of the (b-1) first anionic polymer, i.e., hyaluronic acid or a derivative thereof may be 2,000 kDa or less, preferably 1,000 kDa or less, and more preferably 100 kDa or less. The molecular weight of the (b-1) first anionic polymer, i.e,, hyaluronic acid or a derivative thereof may be 0.4 kDa or more, preferably 1 kDa or more, and more preferably 10 kDa or more.

The molecular weight of the (b-1) first anionic polymer, i.e., hyaluronic acid or a derivative thereof may be from 0.4 to 2,000 kDa, preferably from 1 to 1,000 kDa, and more preferably 10 to 100 kDa.

Finally, the term "hyaluronic acid and derivatives thereof' also comprises hyaluronic acid esters, in particular those in which all or some of the carboxylic groups of the acid functions are esterified with oxyethylenated alkyls or alcohols, containing from 1 to 20 carbon atoms, in particular with a degree of substitution at the level of the D-glucuronic acid of the hyaluronic acid ranging from 0.5 to 50%.

Mention may in particular be made of methyl, ethyl, n-propyl, n-pentyl, benzyl and dodecyl esters of hyaluronic acid. Such esters have in particular been described in D. Campoccia et al. "Semisynthetic resorbable materials from hyaluronan esterification", Biomaterials 19 (1998) 2101-2127.

The hyaluronic acid derivative may be, for example, acetylated hyaluronic acid or a salt thereof such as sodium acetylated hyaluronate.

The molecular weights indicated above are also valid for the hyaluronic acid esters.

The weight ratio of the amount of the (b-1) first anionic polymer(s) relative to the total weight of the nanoparticles in the composition according to the present invention may be 0.01 or more, preferably 0.02 or more, and more preferably 0.03 or more.

The weight ratio of the amount of the (b-1) first anionic polymer(s) relative to the total weight of the nanoparticles in the composition according to the present invention may be 0.8 or less, preferably 0.7 or less, and more preferably 0.6 or less.

The weight ratio of the amount of the (b-1) first anionic polymer(s) relative to the total weight of the nanoparticles in the composition according to the present invention may be from 0.01 to 0.8, preferably from 0.02 to 0.7, and more preferably from 0.03 to 0.6.

Second Anionic Polymer:

The (b-2) second anionic polymer is different from the (b-1) first anionic polymer.

The molecular weight of the (b-2) second anionic polymer may be 1 ,000 or more, preferably 10,000 or more, more preferably 50,000 or more, and even more preferably 100,000 or more. Unless otherwise defined in the descriptions, “molecular weight” means a weight average molecular weight.

The (b-2) second anionic polymer may have at least one negatively chargeable and/or negatively charged moiety selected from the group consisting of a sulfuric group, a sulfate group, a sulfonic group, a sulfonate group, a phosphoric group, a phosphate group, a phosphonic group, a phosphonate group, a carboxylic group, and a carboxylate group. The (b-2) second anionic polymer may be a homopolymer or a copolymer. The term “copolymer” is understood to mean both copolymers obtained from two kinds of monomers and those obtained from more than two kinds of monomers, such as terpolymers obtained from three kinds of monomers.

The (b-2) second anionic polymer may be selected from natural and synthetic anionic polymers.

The (b-2) second anionic polymer may comprise at least one hydrophobic chain.

The (b-2) second anionic polymer, which may comprise at least one hydrophobic chain, may be obtained by copolymerization of a monomer (a) chosen from carboxylic acids comprising α,β-ethylenic unsaturation (monomer a’) and 2-acrylamido-2-methylpropanesulphonic acid (monomer a”) with a non-surface-active monomer (b) comprising an ethylenic unsaturation other than (a) and/or a monomer (c) comprising an ethylenic unsaturation resulting from the reaction of an acrylic monomer comprising an a,|3-monoethylenic unsaturation or of an isocyanate monomer comprising a monoethylenic unsaturation with a monohydric nonionic amphiphilic component or with a primary or secondary fatty amine.

Thus, the anionic polymer with at least one hydrophobic chain may be obtained by two synthetic routes:

- either by copolymerization of the monomers (a’) and (c), or (a’), (b) and (c), or (a”) and (c), or (a”), (b) and (c),

- or by modification (and in particular esterification or amidation) of a copolymer formed from the monomers (a’) or from the monomers (a’) and (b), or (a”) and (b), by a monohydric nonionic amphiphilic compound or a primary or secondary fatty amine.

Mention may in particular be made, as 2-acrylamido-2-methylpropanesulphonic acid copolymers, of those disclosed in the article “Micelle formation of random copolymers of sodium 2-(acrylamido)-2-methylpropanesulfonate and nonionic surfactant macromonomer in water as studied by fluorescence and dynamic light scattering - Macromolecules, 2000, Vol. 33, No. 10 - 3694-3704” and in applications EP-A-0 750 899 and EP-A-1 069 172.

The carboxylic acid comprising an a,|3-monoethylenic unsaturation constituting the monomer (a’) can be chosen from numerous acids and in particular from acrylic acid, methacrylic acid, crotonic acid, itaconic acid and maleic acid. It is preferably acrylic or methacrylic acid.

The copolymer can comprise a monomer (b) comprising a monoethylenic unsaturation which does not have a surfactant property. The preferred monomers are those which give waterinsoluble polymers when they are homopolymerized. They can be chosen, for example, from C₁-C₄ alkyl acrylates and methacrylates, such as methyl acrylate, ethyl acrylate, butyl acrylate or the corresponding methacrylates. The more particularly preferred monomers are methyl acrylate and ethyl acrylate. The other monomers which can be used are, for example, styrene, vinyltoluene, vinyl acetate, acrylonitrile and vinylidene chloride. Unreactive monomers are preferred, these monomers being those in which the single ethylenic group is the only group which is reactive under the polymerization conditions. However, monomers that comprise groups which react under the effect of heat, such as hydroxyethyl acrylate, can optionally be used. The monomer (c) is obtained by reaction of an acrylic monomer comprising α,β- monoethylenic unsaturation, such as (a), or of an isocyanate monomer comprising monoethylenic unsaturation with a monohydric nonionic amphiphilic compound or a primary or secondary fatty amine,

The monohydric nonionic amphiphilic compounds or the primary or secondary fatty amines used to produce the nonionic monomer (c) are well known. The monohydric nonionic amphiphilic compounds are generally alkoxylated hydrophobic compounds comprising an alkylene oxide forming the hydrophilic part of the molecule. The hydrophobic compounds are generally composed of an aliphatic alcohol or an alkylphenol, in which compounds a carbonaceous chain comprising at least six carbon atoms constitutes the hydrophobic part of the amphiphilic compound,

The preferred monohydric nonionic amphiphilic compounds are compounds having the following formula (V):

R-(OCH₂CHR’)_m-(OCH₂CH₂)_n-OH (V) in which R is chosen from alkyl or alkylene groups comprising from 6 to 30 carbon atoms and alkylaryl groups having alkyl radicals comprising from 8 to 30 carbon atoms, R’ is chosen from alkyl groups comprising from 1 to 4 carbon atoms, n is a mean number ranging from approximately 1 to 150 and m is a mean number ranging from approximately 0 to 50, provided that n is at least as great as m.

Preferably, in the compounds of formula (V), the R group is chosen from alkyl groups comprising from 12 to 26 carbon atoms and alkylphenyl groups in which the alkyl group is C₈-C₁₃; the R’ group is the methyl group; m = 0 and n = 1 to 25.

The preferred primary and secondary fatty amines are composed of one or two alkyl chains comprising from 6 to 30 carbon atoms.

The monomer used to form the nonionic urethane monomer (c) can be chosen from highly varied compounds. Use may be made of any compound comprising a copolymerizable unsaturation, such as an acrylic, methacrylic or allylic unsaturation. The monomer (c) can be obtained in particular from an isocyanate comprising a monoethylenic unsaturation, such as, in particular, a,a-dimethyl-m-isopropenylbenzyl isocyanate.

The monomer (c) can be chosen in particular from acrylates, methacrylates or itaconates of oxyethylenated (1 to 50 EO) C₆-C₃₀ fatty alcohol, such as steareth-20 methacrylate, oxyethylenated (25 EO) behenyl methacrylate, oxyethylenated (20 EO) monocetyl itaconate, oxyethylenated (20 EO) monostearyl itaconate or the acrylate modified by polyoxyethylenated (25 EO) C₁₂-C₂₄ alcohols and from dimethyl-m-isopropenylbenzyl isocyanates of oxyethylenated (1 to 50 EO) C₆-C₃₀ fatty alcohol, such as, in particular, the dimethyl-m-isopropenylbenzyl isocyanate of oxyethylenated behenyl alcohol.

According to a specific embodiment of the present invention, the (b-2) second anionic polymer is chosen from acrylic terpolymers obtained from (a) a carboxylic acid comprising an α,β-ethylenic unsaturation, (b) a non-surface-active monomer comprising an ethylenic unsaturation other than (a), and (c) a nonionic urethane monomer which is the reaction product of a monohydric nonionic amphiphilic compound with an isocyanate comprising a monoethylenic unsaturation.

Mention may in particular be made, as the anionic polymers comprising at least one hydrophobic chain, of the acrylic acid/ethyl acrylate/alkyl acrylate terpolymer, such as the product as a 30% aqueous dispersion sold under the name Acusol 823 by Rohm & Haas; the acrylates/steareth-20 methacrylate copolymer, such as the product sold under the name Aculyn 22 by Rohm & Haas; the (meth)acrylic acid/ethyl acrylate/oxyethylenated (25 EO) behenyl methacrylate terpolymer, such as the product as an aqueous emulsion sold under the name Aculyn 28 by Rohm & Haas; the acrylic acid/oxyethylenated (20 EO) monocetyl itaconate copolymer, such as the product as a 30% aqueous dispersion sold under the name Structure 3001 by National Starch; the acrylic acid/oxyethylenated (20 EO) monostearyl itaconate copolymer, such as the product as a 30% aqueous dispersion sold under the name Structure 2001 by National Starch; the acrylates/acrylate modified by polyoxyethylenated (25 EO) C₁₂-C₂₄ alcohol copolymer, such as the 30-32% copolymer latex sold under the name Synthalen W2000 by 3V SA; or the methacrylic acid/methyl acrylate/dimethyl-meta- isopropenylbenzyl isocyanate of ethoxylated behenyl alcohol terpolymer, such as the product as a 24% aqueous dispersion and comprising 40 ethylene oxide groups disclosed in the document EP-A-0 173 109.

The (b-2) second anionic polymers may also be Polyester-5, such as the product sold under the name of Eastman AQ™ 55S Polymer by EASTMAN CHEMICAL having a chemical formula below.

A: dicarboxylic acid moiety

G: glycol moiety

SO₃'Na⁺: sodium sulfo group

OH: hydroxyl group

It may be preferable that the (b-2) second anionic polymer be selected from the group consisting of polysaccharides such as carrageenan (e.g., i-carrageenan, and A-carrageenan), pectin, alginic acid (algin), and cellulose polymers (e.g., carboxymethylcellulose), anionic (co)polyaminoacids such as (co)polyglutamic acids, (co)poly(meth)acrylic acids, (co)polyamic acids, (co)polystyrene sulfonate, (co)poly(vinyl sulfate), dextran sulfate, chondroitin sulfate, (co)polymaleic acids, (co)polyfumaric acids, maleic acid (co)polymers, and salts thereof.

The maleic acid copolymer may comprise one or more maleic acid comonomers, and one or more comonomers chosen from vinyl acetate, vinyl alcohol, vinylpyrrolidone, olefins comprising from 2 to 20 carbon atoms, and styrene.

Thus, the "maleic acid copolymer" is understood to mean any polymer obtained by copolymerization of one or more maleic acid comonomers and of one or more comonomers chosen from vinyl acetate, vinyl alcohol, vinylpyrrolidone, olefins comprising from 2 to 20 carbon atoms, such as octadecene, ethylene, isobutylene, diisobutylene or isooctylene, and styrene, the maleic acid comonomers optionally being partially or completely hydrolysed. Use will preferably be made of hydrophilic polymers, that is to say polymers having a solubility of water of greater than or equal to 2 g/1.

In an advantageous aspect of the present invention, the maleic acid copolymer may have a molar fraction of maleic acid units of between 0.1 and 1 and preferably between 0.4 and 0.9.

The weight-average molar mass of the maleic acid copolymer may be between 1,000 and 500,000 and preferably between 1,000 and 50,000.

It is preferable that the maleic acid copolymer be a styrene/maleic acid copolymer, and more preferably sodium styrene/maleic acid copolymer.

Use will preferably be made of a copolymer of styrene and of maleic acid in a 50/50 ratio.

Use may be made, for example, of the styrene/maleic acid (50/50) copolymer, in the form of an ammonium salt at 30% in water, sold under the reference SMA1000H® by Cray Valley or the styrene/maleic acid (50/50) copolymer, in the form of a sodium salt at 40% in water, sold under the reference SMAlOOOHNa® by Cray Valley.

It may be preferable that the (b-2) second anionic polymer be selected from the group consisting of carrageenan such as ι-carrageenan and Λ-carrageenan, algin, chondroitin sulfate, pectin, and a mixture thereof.

It may be more preferable that the (b-2) second anionic polymer be selected from the group consisting of carrageenan, pectin and a mixture thereof.

The weight ratio of the amount of the (b-2) second anionic polymer(s) relative to the total weight of the nanoparticles in the composition according to the present invention is 0.26 or more, preferably 0.28 or more, and more preferably 0.30 or more.

The weight ratio of the amount of the (b-2) second anionic polymer(s) relative to the total weight of the nanoparticles in the composition according to the present invention may be 0.9 or less, preferably 0.8 or less, and more preferably 0.7 or less.

The weight ratio of the amount of the (b-2) second anionic polymer(s) relative to the total weight of the nanoparticles in the composition according to the present invention may be from 0.26 to 0.9, preferably from 0.28 to 0.8, and more preferably from 0.30 to 0.7.

(Non-Polymeric Acid)

The composition according to the present invention includes (c) at least one non-polymeric acid or salt(s) thereof. Two or more different types of non-polymeric acids or salts thereof may be used in combination. Thus, a single type of a non-polymeric acid or a salt thereof or a combination of different types of non-polymeric acids or salts thereof may be used.

The (c) non-polymeric acid(s) or salt(s) thereof may be selected from monovalent non- polymeric acids and salts thereof, polyvalent (e.g., divalent or trivalent) non-polymeric acids and salts thereof, and mixtures thereof. The monovalent polymeric acids may have only one pKa value. On the other hand, the polyvalent non-polymeric acids may have two or more pKa values. The pKa value (acid dissociation constant) is well known to those skilled in the art, and should be determined at a constant temperature such as 25°C.

The (c) non-polymeric acid or salt(s) thereof can be included in the nanoparticles which may be a polyion complex. The polyvalent non-polymeric acid or salt(s) thereof can function as a crosslinker for the (a) cationic polymer, or the (a) cationic polymer and the (b-1) first anionic polymer and/or the (b-2) second anionic polymer.

The term “non-polymeric” here means that the acid is not obtained by polymerizing two or more monomers, Therefore, the non-polymeric acid does not correspond to an acid obtained by polymerizing two or more monomers such as polycarboxylic acid.

It is preferable that the molecular weight of the (c) non-polymeric acid or salt(s) thereof be 1,000 or less, preferably 800 or less, and more preferably 700 or less.

The term "salt" here means a salt formed by addition of suitable base(s) to the non-polymeric acid, which may be obtained from a reaction with the non-polymeric acid with the base(s) according to methods known to those skilled in the art. As the salt, mention may be made of metal salts, for example salts with alkaline metal such as Na and K, and salts with alkaline earth metal such as Mg and Ca, and ammonium salts.

The (c) non-polymeric acid or salt(s) thereof may be an organic or inorganic acid or salt(s) thereof, and preferably a hydrophilic or water-soluble organic acid or salt(s) thereof.

The monovalent non-polymeric acid has a single acid group which may be selected from the group consisting of a carboxylic group, a sulfuric group, a sulfonic group, a phosphoric group, a phosphonic group, or a phenolic hydroxyl group.

The polyvalent non-polymeric acid has at least two acid groups which may be selected from the group consisting of a carboxylic group, a sulfuric group, a sulfonic group, a phosphoric group, a phosphonic group, a phenolic hydroxyl group, and a mixture thereof.

The monovalent non-polymeric acid may preferably be selected from monovalent carboxylic acids.

In one embodiment, the monovalent non-polymeric acid may be selected from hydroxyl acids, and preferably alpha-hydroxy acids. As the alpha-hydroxy acids, mention may be made of, for example, lactic acid and glycolic acid.

The polyvalent non-polymeric acid or a salt thereof may be selected from the group consisting of oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, fumaric acid, maleic acid, malic acid, citric acid, aconitic acid, oxaloacetic acid, tartaric acid, and salts thereof; aspartic acid, glutamic acid, and salts thereof; terephthalylidene dicamphor sulfonic acid or salts thereof (Mexoryl SX), Benzophenone-9; phytic acid, and salts thereof; Red 2 (Amaranth), Red 102 (New Coccine), Yellow 5 (Tartrazine), Yellow 6 (Sunset Yellow FCF), Green 3 (Fast Green FCF), Blue 1 (Brilliant Blue FCF), Blue 2 (Indigo Carmine), Red 201 (Lithol Rubine B), Red 202 (Lithol Rubine BCA), Red 204 (Lake Red CBA), Red 206 (Lithol Red CA), Red 207 (Lithol Red BA), Red 208 (Lithol Red SR), Red 219 (Brilliant Lake Red R), Red 220 (Deep Maroon), Red 227 (Fast Acid Magenta), Yellow 203 (Quinoline Yellow WS), Green 201 (Alizanine Cyanine Green F), Green 204 (Pyranine Cone), Green 205 (Light Green SF Yellowish), Blue 203 (Patent Blue CA), Blue 205 (Alfazurine FG), Red 401 (Violamine R), Red 405 (Permanent Re F5R), Red 502 (Ponceau 3R), Red 503 (Ponceau R), Red 504 (Ponceau SX), Green 401 (Naphtol Green B), Green 402 (Guinea Green B), and Black 401 (Naphtol Blue Black); folic acid, ascorbic acid, erythorbic acid, and salts thereof; cystine and salts thereof; EDTA and salts thereof; glycyrrhizin and salts thereof; and a mixture thereof.

It may be preferable that the polyvalent non-polymeric acid or a salt thereof be selected from the group consisting of terephthalylidene dicamphor sulfonic acid and salts thereof (Mexoryl SX), Yellow 6 (Sunset Yellow FCF), ascorbic acid, phytic acid and salts thereof, and a mixture thereof,

The (c) non-polymeric acid or a salt thereof may be selected from the group consisting of phytic acid, citric acid, lactic acid and a mixture thereof.

The weight ratio of the amount of the (c) non-polymeric acid(s) or salt(s) thereof relative to the total weight of the nanoparticles in the composition according to the present invention is 0.03 or more, preferably 0,035 or more, and more preferably 0.04 or more.

The weight ratio of the amount of the (c) non-polymeric acid(s) or salt(s) thereof relative to the total weight of the nanoparticles in the composition according to the present invention may be 0.6 or less, preferably 0.5 or less, and more preferably 0.4 or less.

The weight ratio of the amount of the (c) non-polymeric acid(s) or salt(s) thereof relative to the total weight of the nanoparticles in the composition according to the present invention may be from 0.03 to 0.6, preferably from 0.035 to 0.5, and more preferably from 0.04 to 0.4.

[Metal Salt]

The composition according to the present invention may comprise (d) at least one metal salt. Two or more metal salts may be used in combination.

The (d) at least one metal salt is an optional ingredient. Thus, the nanoparticles may not comprise the (d) metal salt.

The term “metal salt” here means a cosmetically-acceptable water-soluble salt that provides cationic ions in an aqueous medium. The metal salt used in the composition of the present invention is preferably selected from polyvalent metal salts, such as divalent or trivalent metal salts, and is more preferably selected from divalent metal salts such as calcium, magnesium, and zinc salts. Calcium salts, such as calcium chloride, calcium pyrrolidone carboxylate (PCA), calcium acetate, calcium aspartate, calcium lactate, are preferred. Among others, calcium chloride and calcium pyrrolidone carboxylate are most preferable.

The (d) metal salt may be selected from polyvalent metal salts, preferably divalent metal salts, more preferably calcium salts such as calcium chloride and calcium pyrrolidone carboxylate, and magnesium salts such as magnesium chloride. The weight ratio of the amount of the (d) metal salt(s) relative to the total weight of the nanoparticles in the composition according to the present invention may be 0,001 or more, preferably 0,005 or more, and more preferably 0.01 or more.

The weight ratio of the amount of the (d) metal salt(s) relative to the total weight of the nanoparticles in the composition according to the present invention is 0.30 or less, preferably 0.25 or less, and more preferably 0.20 or less.

The weight ratio of the amount of the (d) metal salt relative to the total weight of the nanoparticles in the composition according to the present invention may be from 0.001 to 0.30, preferably from 0.005 to 0.25, and more preferably from 0.01 to 0.20,

[Fatty Acid]

The composition according to the present invention comprises (e) at least one fatty acid. If two or more fatty acids are used, they may be the same or different.

The term “fatty acid” here means a carboxylic acid with a long aliphatic carbon chain.

The (e) fatty acid has at least 4 carbon atoms, preferably at least 6 carbon atoms, and more preferably at least 8 carbon atoms. The (e) fatty acid may comprise up to 24 carbon atoms, preferably up to 22 carbon atoms, and more preferably up to 20 carbon atoms. It is preferable that the (e) fatty acid be selected from C₄-C₂₄ fatty acid, more preferably C₆-C₂₂ fatty acid, and even more preferably C₈-C₂₀ fatty acid.

The (e) fatty acid may be selected from saturated fatty acids which may be linear or branched.

As the saturated fatty acid, mention may be made of, for example, caprylic acid (C₈), pelargonic acid (C₉), capric acid (C₁₀), lauric acid (C₁₂), myristic acid (C₁₄), pentadecanoic acid (C₁₅), palmitic acid (C₁₆), heptadecanoic acid (C₁₇), stearic acid (C₁₈), isostearic acid (C₁₈), nonadecanoic acid (C₁₉), arachidic acid (C₂₀), behenic acid (C₂₂), and lignoceric acid (C₂₄).

The (e) fatty acid may be selected from unsaturated fatty acids which may be linear or branched.

As the unsaturated, linear or branched fatty acids, mono-unsaturated, linear or branched fatty acids or polyunsaturated, linear or branched fatty acids may be used. As the unsaturated moiety of the unsaturated, linear or branched fatty acids, a carbon-carbon double bond or a carbon-carbon triple bond may be mentioned.

As the unsaturated fatty acid, mention may be made of, for example, myristoleic acid (C₁₄), palmitoleic acid (C₁₆), oleic acid (C₁₈), linoleic acid (C₁₈), linolenic acid (C₁₈), elaidic acid (C₁₈), arachidonic acid (C₂₀), eicosenoic acid (C₂₀), erucic acid (C₂₂), and nervonic acid (C₂₄).

In a preferred embodiment, the (e) fatty acid may be selected from saturated or unsaturated, linear or branched fatty acids. Thus, the (e) fatty acid may be selected from C₄-C₂₂, preferably C₆-C₂₀, more preferably C₈-C₁₈ saturated and unsaturated, linear or branched fatty acids. The (e) fatty acid may be selected from the group consisting of caprylic acid, capric acid, oleic acid, linoleic acid, myristic acid, stearic acid, isostearic acid, behenic acid, and mixtures thereof.

The (e) fatty acid may be in the form of a free acid or in the form of a salt thereof. As a salt of the fatty acid, mention may be made of an inorganic salt such as an alkali metal salt (a sodium salt, a potassium salt, or the like) and an alkaline earth metal salt (a magnesium salt, a calcium salt, or the like); and an organic salt such as an ammonium salt (a quaternary ammonium salt or the like) and an amine salt (a triethanolamine salt, a triethylamine salt, or the like). A single type of fatty acid salt or a combination of different type of fatty acid salts may be used. Further, a combination of one or more fatty acid in the form of a free acid and one or more fatty acid in the form of a salt may be used, in which one or more type of salts may also be used.

The weight ratio of the amount of the (e) fatty acid(s) relative to the total weight of the nanoparticles in the composition according to the present invention is 0.001 or more, preferably 0.002 or more, and more preferably 0.003 or more.

The weight ratio of the amount of the (e) fatty acid(s) relative to the total weight of the nanoparticles in the composition according to the present invention may be 0.4 or less, preferably 0,3 or less, and more preferably 0,2 or less.

The weight ratio of the amount of the (e) fatty acid(s) relative to the total weight of the nanoparticles in the composition according to the present invention may range from 0.001 to 0.4, preferably from 0.002 to 0.3, and more preferably from 0.003 to 0.2.

[Water]

The composition according to the present invention includes (f) water.

The amount of the (f) water in the composition according to the present invention may be 50% by weight or more, preferably 60% by weight or more, and more preferably 70% by weight or more, relative to the total weight of the composition.

The amount of the (f) water in the composition according to the present invention may be 95% by weight or less, preferably 90% by weight or less, and more preferably 85% by weight or less, relative to the total weight of the composition.

[pH]

The pH of the composition according to the present invention may be from 3 to 9, preferably from 3.3 to 8.5, and more preferably from 3.5 to 8.

At a pH of from 3 to 9, the polyion complex formed by the ingredients (a) to (e), in particular the ingredients (a), (b-1), (b-2) and (c) can be very stable. The pH of the composition according to the present invention may be adjusted by adding at least one alkaline agent and/or at least one acid, other than the (c) non-polymeric acid or salt(s) thereof, The pH of the composition according to the present invention may also be adjusted by adding at least one buffering agent.

(Alkaline Agent)

The composition according to the present invention may comprise at least one alkaline agent. Two or more alkaline agents may be used in combination. Thus, a single type of alkaline agent or a combination of different types of alkaline agents may be used.

The alkaline agent may be an inorganic alkaline agent. It is preferable that the inorganic alkaline agent be selected from the group consisting of ammonia; alkaline metal hydroxides; alkaline earth metal hydroxides; alkaline metal phosphates and monohydrogenophosphates such as sodium phosphate or sodium monohydrogen phosphate.

As examples of the inorganic alkaline metal hydroxides, mention may be made of sodium hydroxide and potassium hydroxide. As examples of the alkaline earth metal hydroxides, mention may be made of calcium hydroxide and magnesium hydroxide. As an inorganic alkaline agent, sodium hydroxide is preferable.

The alkaline agent may be an organic alkaline agent. It is preferable that the organic alkaline agent be selected from the group consisting of monoamines and derivatives thereof; diamines and derivatives thereof; polyamines and derivatives thereof; basic amino acids and derivatives thereof; oligomers of basic amino acids and derivatives thereof; polymers of basic amino acids and derivatives thereof; urea and derivatives thereof; and guanidine and derivatives thereof.

As examples of the organic alkaline agents, mention may be made of alkanolamines such as mono-, di- and tri-ethanolamine, and isopropanolamine; urea, guanidine and their derivatives; basic amino acids such as lysine, ornithine or arginine; and diamines such as those described by the structure below:

wherein R denotes an alkylene such as propylene, optionally substituted by a hydroxyl or a C₁-C₄ alkyl radical, and R₁, R₂, R₃ and R₄ independently denote a hydrogen atom, an alkyl radical or a C₁-C₄ hydroxyalkyl radical, which may be exemplified by 1,3-propanediamine and derivatives thereof. Arginine, urea and monoethanolamine are preferable.

The alkaline agent(s) may be used in a total amount of from 0,01% to 15% by weight, preferably from 0.02% to 10% by weight, more preferably from 0.03% to 5% by weight, relative to the total weight of the composition, depending on their solubility.

(Acid)

The composition according to the present invention may comprise at least one acid. Two or more acids may be used in combination. Thus, a single type of acid or a combination of different types of acids may be used. As the acid, mention may be made of any inorganic or organic acids, preferably inorganic acids, which are commonly used in cosmetic products. A monovalent acid and/or a polyvalent acid may be used. A monovalent acid such as sulfuric acid, phosphoric acid and hydrochloric acid (HC1) may be used. HC1 is preferable.

The acid(s) may be used in a total amount of from 0.01% to 15% by weight, preferably from 0.02% to 10% by weight, more preferably from 0.03% to 5% by weight, relative to the total weight of the composition, depending on their solubility.

(Buffering Agent)

The composition according to the present invention may comprise at least one buffering agent. Two or more buffering agents may be used in combination. Thus, a single type of buffering agent or a combination of different types of buffering agents may be used.

As the buffering agent, mention may be made of an acetate buffer (for example, acetic acid + sodium acetate), a phosphate buffer (for example, sodium dihydrogen phosphate + di-sodium hydrogen phosphate), a citrate buffer (for example, citric acid + sodium citrate), a borate buffer (for example, boric acid + sodium borate), a tartrate buffer (for example, tartaric acid + sodium tartrate dihydrate), a Tris buffer (for example, tris(hydroxymethyl)aminomethane), and a Hepes buffer (4-(2-hydroxyethyl)-l -piperazineethanesulfonic acid).

[Optional Ingredients]

The composition according to the present invention may comprise, in addition to the aforementioned essential ingredients, at least one optional ingredient typically employed in cosmetics, which may be selected from, specifically, oils, surfactants or emulsifiers, hydrophilic or lipophilic thickeners, organic volatile or non-volatile solvents such as polyols, in particular glycerin and glycols, silicones and silicone derivatives, natural extracts derived from animals or vegetables, waxes, fillers, UV filters, and the like, within a range which does not impair the effects of the present invention.

The composition according to the present invention may comprise the above optional ingredient(s) in an amount of from 0.01% to 50% by weight, preferably from 0.05% to 30% by weight, and more preferably from 0.1% to 10% by weight, relative to the total weight of the composition.

However, it is preferable that the composition according to the present invention include a very limited amount of surfactant(s) or emulsifier(s). The amount of the surfactant(s) or emulsifier(s) in the composition according to the present invention may be 1% by weight or less, preferably 0.1% by weight or less, and more preferably 0.01% by weight or less, relative to the total weight of the composition. It is in particular preferable that the composition according to the present invention includes no surfactant or emulsifier.

[Composition]

The composition according to the present invention can be prepared by mixing the essential ingredient(s) as explained above, and optional ingredient(s), if necessary, as explained above. The method and means to mix the above essential and optional ingredients are not limited. Any conventional method and means can be used to mix the above essential and optional ingredients to prepare the composition according to the present invention.

The composition according to the present invention may be intended to be used as a cosmetic composition. Thus, the cosmetic composition according to the present invention may be intended for application onto a keratin substance. Keratin substance here means a material containing keratin as a main constituent element, and examples thereof include the skin, scalp, nails, lips, hair, and the like, Thus, it is preferable that the cosmetic composition according to the present invention be used for a cosmetic process for the keratin substance, in particular skin.

The composition according to the present invention can be transparent or translucent, preferably transparent.

The transparency may be measured by measuring the turbidity (for example, turbidity can be measured with a 2100Q (marketed by Hach Company) having a round cell (25 mm in diameter and 60 mm height) and a tungsten filament lamp which can emit visible light (between 400 and 800 nm, preferably from 400 to 500 nm). The measurement can be performed on the undiluted composition. The blank may be determined with distilled water.

The composition according to the present invention may have a turbidity of 300 NTU or less, preferably 200 NTU or less, more preferably 100 NTU or less, and even more preferably 50 NTU or less.

[Cosmetic Process and Use]

The present invention also relates to: a cosmetic process for a keratin substance such as skin, comprising: applying to the keratin substance the composition according to the present invention.

The cosmetic process here means a non-therapeutic cosmetic method for caring for and/or making up the surface of a keratin substance such as skin.

The cosmetic process according to the present invention can provide a keratin substance such as skin with cosmetic effects derived from hyaluronic acid and/or hyaluronic acid derivative. For example, the cosmetic process according to the present invention can provide a keratin substance such as skin with moisturizing effects,

The present invention may also relate to a use of (e) at least one fatty acid in a composition comprising:

(a) at least one cationic polymer;

(c) at least one non-polymeric acid or a salt thereof; and

(d) at least one optional metal salt; and

(f) water, wherein the ingredients (a), (b-1), (b-2), (c), (d) and (e) are capable of forming nanoparticles, the amount of which is from 0,01% to 0.58% by weight, preferably from 0.05% to 0.57% by weight, and more preferably from 0.1% to 0.56% by weight, relative to the total weight of the composition, the weight ratio of the amount of the (a) cationic polymer(s) relative to the total weight of the nanoparticles is from 0.06 to 0.25, the weight ratio of the amount of the (b-2) second anionic polymer relative to the total weight of the nanoparticles is 0.26 or more, the weight ratio of the amount of the (c) non-polymeric acid(s) or salt(s) thereof relative to the total weight of the nanoparticles is 0.03 or more, the weight ratio of the amount of the (d) optional metal salt(s) relative to the total weight of the nanoparticles is 0.30 or less, and the weight ratio of the amount of the (e) fatty acid(s) relative to the total weight of the nanoparticles is 0.001 or more, in order to enhance the penetration ability of the nanoparticles into a keratin substance such as skin.

The above use can deliver hyaluronic acid and/or hyaluronic acid derivative deeper into a keratin substance such as skin. Therefore, the above use according to the present invention can provide a keratin substance such as skin with cosmetic effects derived from hyaluronic acid and/or hyaluronic acid derivative. For example, the use according to the present invention can provide a keratin substance such as skin with moisturizing effects.

EXAMPLES

The present invention will be described in a more detailed manner by way of examples. However, they should not be construed as limiting the scope of the present invention.

[Example 1 and Comparative Example 1]

[Preparation]

Each of the compositions according to Example 1 and Comparative Example 1 was prepared by mixing the ingredients shown in Table 1. The numerical values for the amounts of the ingredients in Table 1 are all based on “% by weight” as active materials.

The compositions according to Example 1 and Comparative Example 1 included nanoparticles including hyaluronic acid. The “HANP” in Table 1 is an abbreviation of Hyaluronic Acid Nano-Particle. The (a) to (f) in Table 1 correspond to those in the claims. Table 1

[Evaluations]

(Skin Depth Penetrated by Hyaluronic Acid)

Penetration test experiments were performed using a Franz diffusion cell (Hanson) with a dermatomed human skin provided from Biopredic International (France). This equipment was composed of a donor part and a receptor part, with the dermatomed human skin between the donor and receptor parts. The receptor part with a predetermined volume was filled with a receiving solution (phosphate buffer solution at a pH of 7) maintained at a temperature of 32°C, which was continuously stirred with a small magnetic bar. Each of the compositions according to Example 1 and Comparative Example 1 was spread with a spatula on the membrane of the donor part with an amount of 30 mg/cm². After 24 hours, the dermatomed human skin was removed and cryosectioned, and the penetration depth of HANP was measured by the cross-sectional observation with a fluorescence microscope.

The results are shown in the line labeled “Skin Depth Penetrated by Hyaluronic Acid (μm)” in Table 1.

(Appearance) The aspect of the compositions according to Example 1 and Comparative Example 1 was visually evaluated at room temperature (25°C) in accordance with the following criteria.

Good: Transparent

Poor: Turbid

The results are shown in the line labelled “Appearance” in Table 1.

(Particle Size)

The particle size or diameter of the HANP in the compositions according to Example 1 and Comparative Example 1 was measured by a particle size analyzer ELSZ-2000 by Otsuka Electronics Co., Ltd. at room temperature (25°C).

The results are shown in the line labelled “Particle Size (nm)” in Table 1.

(Turbidity)

The turbidity of the compositions according to Example 1 and Comparative Example 1 was measure by a turbidity meter 2100Q (Hach Company) at room temperature (25°C).

The results are shown in the line labelled “Turbidity (NTU)” in Table 1.

(Summary)

The experimental data shown in Table 1 demonstrate that HANP hydrophobicized with fatty acid penetrated deeper into the skin than HANP without being hydrophobicized.

Thus, the nanoparticles in the composition according to the present invention, including (e) at least one fatty acid, can penetrate deeper into the skin.

[Examples 2-6 and Comparative Example 2]

[Preparation]

Each of the compositions according to Examples 2-6 and Comparative Example 2 was prepared by mixing the ingredients shown in Table 2. The numerical values for the amounts of the ingredients in Table 2 are all based on “% by weight” as active materials.

The compositions according to Examples 2-6 and Comparative Example 2 included particles including hyaluronic acid. The “HANP” in Table 2 is an abbreviation of Hyaluronic Acid Nano-Particle. The (a) to (f) in Table 2 correspond to those in the claims. Table 2

[Evaluations]

(Appearance)

The aspect of the compositions according to Examples 2-6 and Comparative Example 2 was visually evaluated at room temperature (25°C) in accordance with the following criteria.

Good: Transparent

Poor: Precipitation was observed

The results are shown in the line labelled “Appearance” in Table 2.

(Particle Size)

The particle size or diameter of the HANP in the compositions according to Examples 2-6 and Comparative Example 2 was measured by a particle size analyzer ELSZ-2000 by Otsuka Electronics Co., Ltd. at room temperature (25°C),

The results are shown in the line labelled “Particle Size (nm)” in Table 2.

(Turbidity)

The turbidity of the compositions according to Examples 2-6 and Comparative Example 2 was measure by a turbidity meter 2100Q (Hach Company) at room temperature (25°C).

The results are shown in the line labelled “Turbidity (NTU)” in Table 2.

(Summary)

The experimental data shown in Table 2 demonstrate that if the amount of the nanoparticles is 0.59% by weight or more, relative to the total weight of the composition, precipitations occur.

[Reference Example 1 and Examples 7-11]

[Preparation]

Each of the compositions according to Reference Example 1 and Examples 7-11 was prepared by mixing the ingredients shown in Table 3. The numerical values for the amounts of the ingredients in Table 3 are all based on “% by weight” as active materials.

The compositions according to Reference Example 1 and Examples 7-11 included particles including hyaluronic acid (except for Reference Example 1). The “HANP” in Table 3 is an abbreviation of Hyaluronic Acid Nano-Particle. The (a) to (f) in Table 3 correspond to those in the claims. Table3

[Evaluations]

(Appearance)

The aspect of the compositions according to Reference Example 1 and Examples 7-11 was visually evaluated at room temperature (25°C) in accordance with the following criteria.

Good: Transparent

Poor: Turbid

The results are shown in the line labelled “Appearance” in Table 3.

(Particle Size)

The particle size or diameter of the HANP in the compositions according to Reference Example 1 and Examples 7-11 was measured by a particle size analyzer ELSZ-2000 by Otsuka Electronics Co., Ltd. at room temperature (25°C).

The results are shown in the line labelled “Particle Size (nm)” in Table 3.

(Turbidity)

The turbidity of the compositions according to Reference Example 1 and Examples 7-11 was measure by a turbidity meter 2100Q (Hach Company) at room temperature (25°C).

The results are shown in the line labelled “Turbidity (NTU)” in Table 3.

(Summary)

The experimental data shown in Table 3 demonstrate that nanoparticles can be prepared without depending on the amount of the (b-1) first anionic polymer.

However, if no (b-1) first anionic polymer is used (Reference Example 1), cosmetic effects derived from the (b-1) first anionic polymer cannot be obtained.

[Examples 12-15 and Comparative Examples 3-6]

[Preparation]

Each of the compositions according to Examples 12-15 and Comparative Examples 3-6 was prepared by mixing the ingredients shown in Table 4. The numerical values for the amounts of the ingredients in Table 4 are all based on “% by weight” as active materials.

The compositions according to Examples 12-15 and Comparative Examples 3-6 included particles including hyaluronic acid. The “HANP” in Table 4 is an abbreviation of Hyaluronic Acid Nano-Particle. The (a) to (f) in Table 4 correspond to those in the claims.

[Evaluations]

(Appearance)

The aspect of the compositions according to Examples 12-15 and Comparative Examples 3-6 was visually evaluated at room temperature (25°C) in accordance with the following criteria.

Good: Transparent

Poor: Turbid

The results are shown in the line labelled “Appearance” in Table 4.

(Particle Size)

The particle size or diameter of the HANP in the compositions according to Examples 12-15 and Comparative Examples 3-6 was measured by a particle size analyzer ELSZ-2000 by Otsuka Electronics Co., Ltd. at room temperature (25°C).

The results are shown in the line labelled “Particle Size (nm)” in Table 4.

(Turbidity)

The turbidity of the compositions according to Examples 12-15 and Comparative Examples 3- 6 was measure by a turbidity meter 2100Q (Hach Company) at room temperature (25°C).

The results are shown in the line labelled “Turbidity (NTU)” in Table 4.

(Summary)

The experimental data shown in Table 4 demonstrate that if the weight ratio of the amount of the (b-2) second anionic polymer, relative to the total weight of the nanoparticles, is 0.254 or less, the appearance of a composition including the nanoparticles becomes turbid (not transparent).

[Examples 16-20 and Comparative Examples 7-9]

[Preparation]

Each of the compositions according to Examples 16-20 and Comparative Examples 7-9 was prepared by mixing the ingredients shown in Table 5. The numerical values for the amounts of the ingredients in Table 5 are all based on “% by weight” as active materials.

The compositions according to Examples 16-20 and Comparative Examples 7-9 included particles including hyaluronic acid. The “HANP” in Table 5 is an abbreviation of Hyaluronic Acid Nano-Particle. The (a) to (f) in Table 5 correspond to those in the claims. Tables

[Evaluations]

(Appearance)

The aspect of the compositions according to Examples 16-20 and Comparative Examples 7-9 was visually evaluated at room temperature (25°C) in accordance with the following criteria.

Good: Transparent

Poor: Precipitation was observed

The results are shown in the line labelled “Appearance” in Table 5.

(Particle Size)

The particle size or diameter of the HANP in the compositions according to Examples 16-20 and Comparative Examples 7-9 was measured by a particle size analyzer ELSZ-2000 by Otsuka Electronics Co., Ltd. at room temperature (25°C).

The results are shown in the line labelled “Particle Size (nm)” in Table 5.

NA (Not Available) in Table 5 means that no nanoparticles were found.

(Turbidity)

The turbidity of the compositions according to Examples 16-20 and Comparative Examples 7- 9 was measure by a turbidity meter 2100Q (Hach Company) at room temperature (25°C).

The results are shown in the line labelled “Turbidity (NTU)” in Table 5.

(Summary)

The experimental data shown in Table 5 demonstrate that if the weight ratio of the amount of the (a) cationic polymer, relative to the total weight of particles, is 0,057 or less, the particles cannot have a nano-size (less than 1000 nm), and that if the weight ratio of the amount of the (a) cationic polymer, relative to the total weight of particles, is 0.258 or more, precipitates occur and the turbidity of a composition including the particles becomes too high.

[Examples 21-26 and Comparative Examples 10-11]

[Preparation]

Each of the compositions according to Examples 21-26 and Comparative Examples 10-11 was prepared by mixing the ingredients shown in Table 6. The numerical values for the amounts of the ingredients in Table 6 are all based on “% by weight” as active materials.

The compositions according to Examples 21-26 and Comparative Examples 10-11 included particles including hyaluronic acid, The “HANP” in Table 6 is an abbreviation of Hyaluronic Acid Nano-Particle. The (a) to (f) in Table 6 correspond to those in the claims. Tableo

[Evaluations]

(Appearance)

The aspect of the compositions according to Examples 21-26 and Comparative Examples 10- 11 was visually evaluated at room temperature (25°C) in accordance with the following criteria.

Good: Transparent

Poor: Gel

The results are shown in the line labelled “Appearance” in Table 6.

(Particle Size)

The particle size or diameter of the HANP in the compositions according to Examples 21-26 and Comparative Examples 10-11 was measured by a particle size analyzer ELSZ-2000 by Otsuka Electronics Co., Ltd. at room temperature (25°C).

The results are shown in the line labelled “Particle Size (nm)” in Table 6.

NA (Not Available) in Table 6 means that no nanoparticles were found.

(Turbidity)

The turbidity of the compositions according to Examples 21-26 and Comparative Examples 10-11 was measure by a turbidity meter 2100Q (Hach Company) at room temperature (25°C).

The results are shown in the line labelled “Turbidity (NTU)” in Table 6.

(Summary)

The experimental data shown in Table 6 demonstrate that if the weight ratio of the amount of the (c) non-polymeric acid(s) or salt(s) thereof, relative to the total weight of particles, is 0.022 or less, the particles cannot have a nano-size (less than 1000 nm), and that if the amount of the (c) non-polymeric acid(s) or salt(s) is zero, a gel is formed.

[Examples 27-32 and Comparative Examples 12-13]

[Preparation]

Each of the compositions according to Examples 27-32 and Comparative Examples 12-13 was prepared by mixing the ingredients shown in Table 7. The numerical values for the amounts of the ingredients in Table 7 are all based on “% by weight” as active materials.

The compositions according to Examples 27-32 and Comparative Examples 12-13 included particles including hyaluronic acid. The “HANP” in Table 7 is an abbreviation of Hyaluronic Acid Nano-Particle. The (a) to (f) in Table 7 correspond to those in the claims.

[Evaluations]

(Appearance)

The aspect of the compositions according to Examples 27-32 and Comparative Examples 12- 13 was visually evaluated at room temperature (25°C) in accordance with the following criteria.

Good: Transparent

Poor: Precipitation was observed

The results are shown in the line labelled “Appearance” in Table 7.

(Particle Size)

The particle size or diameter of the HANP in the compositions according to Examples 27-32 and Comparative Examples 12-13 was measured by a particle size analyzer ELSZ-2000 by Otsuka Electronics Co., Ltd. at room temperature (25°C).

The results are shown in the line labelled “Particle Size (nm)” in Table 7.

(Turbidity)

The turbidity of the compositions according to Examples 27-32 and Comparative Examples 12-13 was measure by a turbidity meter 2100Q (Hach Company) at room temperature (25°C).

The results are shown in the line labelled “Turbidity (NTU)” in Table 7.

(Summary)

The experimental data shown in Table 7 demonstrate that if the weight ratio of the amount of the (d) metal salt, relative to the total weight of particles, is 0.323 or more, the particles cannot have a nano-size (less than 1000 nm), and precipitations occur.

[Reference Example 2 and Examples 33-39]

[Preparation]

Each of the compositions according to Reference Example 2 and Examples 33-39 was prepared by mixing the ingredients shown in Table 8. The numerical values for the amounts of the ingredients in Table 8 are all based on “% by weight” as active materials.

The compositions according to Reference Example 2 and Examples 33-39 included nanoparticles including hyaluronic acid. The “HANP” in Table 8 is an abbreviation of Hyaluronic Acid Nano-Particle. The (a) to (f) in Table 8 correspond to those in the claims. Table8

[Evaluations]

(Appearance)

The aspect of the compositions according to Reference Example 2 and Examples 33-39 was visually evaluated at room temperature (25°C) in accordance with the following criteria.

Good: Transparent

Poor: Turbid

The results are shown in the line labelled “Appearance” in Table 8.

(Particle Size)

The particle size or diameter of the HANP in the compositions according to Reference Example 2 and Example 33-39 was measured by a particle size analyzer ELSZ-2000 by Otsuka Electronics Co., Ltd. at room temperature (25°C).

The results are shown in the line labelled “Particle Size (nm)” in Table 8.

(Turbidity)

The turbidity of the compositions according to Reference Example 2 and Examples 33-39 was measure by a turbidity meter 2100Q (Hach Company) at room temperature (25°C).

The results are shown in the line labelled “Turbidity (NTU)” in Table 8.

(Summary)

The experimental data shown in Table 8 demonstrate that nanoparticles can be prepared, without depending on the amount of the (e) fatty acid.

However, if no (e) fatty acid is used (Reference Example 2), skin penetration improvement effects derived from the (e) fatty acid cannot be obtained.

[Examples 40-44]

[Preparation]

Each of the compositions according to Examples 40-44 was prepared by mixing the ingredients shown in Table 9. The numerical values for the amounts of the ingredients in Table 9 are all based on “% by weight” as active materials.

The compositions according to Examples 40-44 included nanoparticles including hyaluronic acid. The “HANP” in Table 9 is an abbreviation of Hyaluronic Acid Nano-Particle. The (a) to (f) in Table 9 correspond to those in the claims. Tabled

[Evaluations]

(Appearance)

The aspect of the compositions according to Examples 40-44 was visually evaluated at room temperature (25°C) in accordance with the following criteria.

Good: Transparent

Poor: Turbid

The results are shown in the line labelled “Appearance” in Table 9.

(Particle Size)

The particle size or diameter of the HANP in the compositions according to Example 40-44 was measured by a particle size analyzer ELSZ-2000 by Otsuka Electronics Co., Ltd. at room temperature (25°C).

The results are shown in the line labelled “Particle Size (nm)” in Table 9.

(Turbidity)

The turbidity of the compositions according to Examples 40-44 was measure by a turbidity meter 2100Q (Hach Company) at room temperature (25°C).

The results are shown in the line labelled “Turbidity (NTU)” in Table 9.

(Summary)

The experimental data shown in Table 9 demonstrate that a variety of hyaluronic acids can be used as the (b-1) first anionic polymer.

[Examples 45-54]

[Preparation]

Each of the compositions according to Examples 45-54 was prepared by mixing the ingredients shown in Table 10. The numerical values for the amounts of the ingredients in Table 10 are all based on “% by weight” as active materials.

The compositions according to Examples 45-54 included nanoparticles including hyaluronic acid. The “HANP” in Table 10 is an abbreviation of Hyaluronic Acid Nano-Particle. The (a) to (f) in Table 10 correspond to those in the claims.

(continued)

(continued')

[Evaluations]

(Appearance)

The aspect of the compositions according to Examples 45-54 was visually evaluated at room temperature (25°C) in accordance with the following criteria.

Good: Transparent

Poor: Turbid

The results are shown in the line labelled “Appearance” in Table 10.

(Particle Size)

The particle size or diameter of the HANP in the compositions according to Example 45-55 was measured by a particle size analyzer ELSZ-2000 by Otsuka Electronics Co., Ltd. at room temperature (25 °C).

The results are shown in the line labelled “Particle Size (nm)” in Table 10.

(Turbidity)

The turbidity of the compositions according to Examples 45-55 was measure by a turbidity meter 2100Q (Hach Company) at room temperature (25°C).

The results are shown in the line labelled “Turbidity (NTU)” in Table 10.

(Summary)

The experimental data shown in Table 10 demonstrate that a variety of (a) cationic polymers, (b-2) second anionic polymers, (c) non-polymeric acid or salt(s) thereof, (d) metal salts, and (e) fatty acids can be used.

Claims

1. A composition, preferably a cosmetic composition, and more preferably a skin cosmetic composition, comprising nanoparticles comprising:

(a) at least one cationic polymer;

(c) at least one non-polymeric acid or a salt thereof;

(d) at least one optional metal salt; and

(e) at least one fatty acid, and

(f) water, wherein the amount of the nanoparticles is from 0.01% to 0,58% by weight, preferably from 0.05% to 0.57% by weight, and more preferably from 0.1% to 0.56% by weight, relative to the total weight of the composition, the weight ratio of the amount of the (a) cationic polymer(s) relative to the total weight of the nanoparticles is from 0.06 to 0.25, the weight ratio of the amount of the (b-2) second anionic polymer relative to the total weight of the nanoparticles is 0.26 or more, the weight ratio of the amount of the (c) non-polymeric acid(s) or salt(s) thereof relative to the total weight of the nanoparticles is 0.03 or more, the weight ratio of the amount of the (d) optional metal salt(s) relative to the total weight of the nanoparticles is 0.30 or less, and the weight ratio of the amount of the (e) fatty acid(s) relative to the total weight of the nanoparticles is 0.001 or more.

2. The composition according to Claim 1 , wherein the (a) cationic polymer has at least one positively chargeable and/or positively charged moiety selected from the group consisting of a primary, secondary or tertiary amino group, a quaternary ammonium group, a guanidine group, a biguanide group, an imidazole group, an imino group, and a pyridyl group.

3. The composition according to Claim 1 or 2, wherein the (a) cationic polymer is selected from the group consisting of cyclopolymers of alkyldiallylamine and cyclopolymers of dialkyldiallylammonium such as (co)polydiallyldialkyl ammonium chloride, (co)polyamines such as chitosans and (co)polylysines, cationic (co)polyaminoacids such as collagen and arginine/lysine polypeptide, cationic cellulose polymers, and salts thereof.

4. The composition according to any one of Claims 1 to 3, wherein the weight ratio of the amount of the (a) cationic polymer(s) relative to the total weight of the nanoparticles in the composition is from 0.06 to 0.24, preferably from 0.07 to 0,22, and more preferably from 0.08 to 0.20.

5. The composition according to any one of Claims 1 to 4, wherein the (b-1) first anionic polymer has a molecular weight of 2,000 kDa or less, preferably 1,000 kDa or less, and more preferably 100 kDa or less.

6. The composition according to any one of Claims 1 to 5, wherein the weight ratio of the amount of the (b-1) first anionic polymer(s) relative to the total weight of the nanoparticles in the composition is from 0.01 to 0.8, preferably from 0.02 to 0.7, and more preferably from 0.03 to 0.6.

7. The composition according to any one of Claims 1 to 6, wherein the (b-2) second anionic polymer is selected from the group consisting of carrageenan, pectin and a mixture thereof.

8. The composition according to any one of Claims 1 to 7, wherein the weight ratio of the amount of the (b-2) second anionic polymer(s) relative to the total weight of the nanoparticles in the composition is from 0.26 to 0,9, preferably from 0.28 to 0.8, and more preferably from 0.30 to 0.7.

9. The composition according to any one of Claims 1 to 8, wherein the (c) non- polymeric acid or salt(s) thereof is selected from the group consisting of phytic acid, citric acid, lactic acid and a mixture thereof.

10. The composition according to any one of Claims 1 to 9, wherein the weight ratio of the amount of the (c) non-polymeric acid(s) or salt(s) thereof relative to the total weight of the nanoparticles in the composition is from 0.03 to 0.6, preferably from 0.035 to 0.5, and more preferably from 0.04 to 0.4.

11. The composition according to any one of Claims 1 to 10, wherein the (d) optional metal salt is selected from polyvalent metal salts, preferably divalent metal salts, more preferably calcium salts such as calcium chloride and calcium pyrrolidone carboxylate, and magnesium salts such as magnesium chloride.

12. The composition according to any one of Claims 1 to 11, wherein the weight ratio of the amount of the (d) optional metal salt relative to the total weight of the nanoparticles in the composition is from 0.001 to 0.30, preferably from 0.005 to 0.25, and more preferably from 0.01 to 0.20.

13. The composition according to any one of Claims 1 to 12, wherein the (e) fatty acid is selected from C₄-C₂₂, preferably C₆-C₂₀, more preferably C₈-C₁₈ saturated and unsaturated, linear or branched fatty acids.

14. The composition according to any one of Claims 1 to 13, wherein the weight ratio of the amount of the (e) fatty acid relative to the total weight of the nanoparticles in the composition is from 0.001 to 0.4, preferably from 0.002 to 0.3, and more preferably from 0.003 to 0.2.

15. The composition according to any one of Claims 1 to 14, wherein the amount of the (f) water in the composition is from 50% to 95% by weight, preferably from 60% to 90% by weight, and more preferably from 70% to 85% by weight, relative to the total weight of the composition. , A cosmetic process for a keratin substance such as skin, comprising applying to the keratin substance the composition according to any one of Claims 1 to 15.