Cosmetic

Abstract

In the present invention, in order to make polyanions that are to be contained in cosmetics into nanosized particles, polyanion particles are formed by stirring and mixing an aqueous solution containing polyanions and an aqueous solution containing two or more species of metal-derived cations.

Description

cosmetics

[0001] The present invention relates to nanoparticles of polyanions to be incorporated into cosmetics. Furthermore, the present invention relates to the use of polyanion nanoparticles in cosmetic treatments.

[0002] Hyaluronic acid is a kind of water-soluble mucopolysaccharide, and has excellent moisturizing properties, but its molecular weight is large, so it hardly penetrates into the skin.Patent document 1 describes the hyaluronic acid particles, which are prepared by adding sodium chloride or sodium citrate to hyaluronic acid aqueous solution and stirring and mixing with vortex mixer, and the average particle diameter is 200nm or less.This particle is considered to be formed by neutralizing the negative charge of hyaluronic acid by electrolyte such as sodium chloride, and by making the intramolecular or intermolecular hydrogen bond based on hydroxyl group etc. in hyaluronic acid predominantly work.

[0003] Non-Patent Document 1 describes that mixing a polyanion such as hyaluronic acid with a trivalent metal ion forms a macroscopic hydrogel.

[0004] WO 2021 / 033725 International Publication Brochure

[0005] Ana Lucia Ramalho Merce, Luiz Carlos Marques Carrera, Lilian Kelly Santos Romanholi, Maria Angeles Lobo Recio, “Aqueous and solid complexes of iron(III) with hyaluronic acid. Potentiometric titrations and infrared spectroscopy studies”, Journal of Inorganic Biochemistry 89 (2002) 212-218

[0006] Polyanions that are incorporated into cosmetics include those containing carboxylic acids (sodium hyaluronate, xanthan gum, and Tremella fuciformis polysaccharide) and those containing sulfonic acids (sodium chondroitin sulfate and sodium dextran sulfate). The present invention aims to provide such polyanions in a fine particulate form suitable for incorporation into cosmetics. The inventors' tests showed that simply adding one type of electrolyte to hyaluronic acid and stirring the mixture resulted in insufficient reduction in particle size.

[0007] The present inventors have found that mixing hyaluronic acid with minerals of complex composition can significantly reduce particle size. Under similar conditions, nanoparticles were also obtained with hyaluronic acid of different molecular weights and polyanions other than hyaluronic acid. Here, nanoparticles refer to particulate substances with a size (diameter if the particle is spherical) of less than 1 micrometer (μm), that is, a few hundred nanometers (nm) or less. Representative aspects of the invention disclosed in this application are shown below.

[0008] (1) A method for producing polyanionic nanoparticles, comprising stirring and mixing an aqueous solution A containing a polyanion with an aqueous solution B containing at least two kinds of divalent metal cations. (2) The method (1) above, wherein the polyanion in aqueous solution A is one or more anionic polymers selected from hyaluronic acid or a salt thereof, xanthan gum or a salt thereof, chondroitin sulfate or a salt thereof, dextran sulfate or a salt thereof, alginic acid or a salt thereof, carboxymethylcellulose or a salt thereof, or Tremella fuciformis polysaccharide or a salt thereof.

[0009] (3) The method according to (1) or (2) above, wherein aqueous solution B further contains one or more monovalent metal cations. (4) The method according to any one of (1) to (3) above, wherein the concentration of the polyanion after mixing aqueous solutions A and B is 0.35% (w / w) or less, preferably 0.27% or less, more preferably 0.22% or less.

[0010] (5) The method according to any one of (1) to (4) above, wherein the ratio of the number of charges on the divalent metal cation to the number of charges on the polyanion after mixing aqueous solutions A and B is 1.1 or more, preferably 1.2 or more, and more preferably 1.3 or more.

[0011] (6) The method according to any one of (1) to (5) above, wherein aqueous solution B is an aqueous solution containing bittern or CSWII (seawater concentrate). (7) The method according to any one of (1) to (6) above, further comprising a step of further reducing the particle size of the obtained polyanionic nanoparticles, for example, a step of mechanically cutting the polymer chains of the polyanionic nanoparticles.

[0012] (8) The method according to any one of (1) to (7) above, wherein aqueous solution A further contains a preservative (e.g., phenoxyethanol). (9) The method according to any one of (1) to (8) above, wherein the polyanionic nanoparticles have a diameter of 600 nm or less, preferably 500 nm or less, more preferably 400 nm or less, and even more preferably 300 nm or less.

[0013] (10) Nanoparticles containing a polyanion and two or more types of divalent metal ions (and may further contain one or more types of monovalent metal ions), and having a particle size of 600 nm or less, preferably 500 nm or less, more preferably 400 nm or less, and even more preferably 300 nm or less.

[0014] (11) The nanoparticles according to (10), wherein the polyanion is one or more anionic polymers selected from hyaluronic acid or a salt thereof, xanthan gum or a salt thereof, chondroitin sulfate or a salt thereof, dextran sulfate or a salt thereof, alginic acid or a salt thereof, carboxymethylcellulose or a salt thereof, or Tremella fuciformis polysaccharide or a salt thereof.

[0015] (12) Nanoparticles produced by the method according to any one of (1) to (9) above, or according to (10) or (11) above. (13) Nanoparticles according to (12) above, which are cosmetic ingredients.

[0016] (14) The method according to any one of (1) to (9) above, which produces an aqueous composition containing polyanionic nanoparticles. (15) The method according to (7) above, which produces an aqueous composition containing polyanionic nanoparticles with reduced viscosity.

[0017] (16) A method for producing an aqueous composition containing polyanionic nanoparticles, comprising: a step of stirring and mixing an aqueous polyanionic solution A and an aqueous solution B containing two or more types of divalent metal cations to form polyanionic nanoparticles; and a step of cutting the polymer chains of the obtained polyanionic nanoparticles by mechanical force (e.g., mastication, ultrasonic waves, high-speed stirring, spraying, capillary flow, bead milling, impact by collision, etc.).

[0018] (17) The method according to (16) above, wherein the concentration of the polyanion after mixing aqueous solutions A and B is 0.01% to 0.35%, and the ratio of the number of charges of the divalent metal cations to the number of charges of the polyanion is 1.1 or more. (18) The method according to (16) or (17) above, wherein the divalent metal cations contained in aqueous solution B include at least magnesium ions and calcium ions.

[0019] (19) The method according to (18) above, wherein (a) the magnesium ion content of aqueous solution B is 0.1 mol / L to 3.5 mol / L and the calcium ion content is 0.5 mmol / L to 1.0 mol / L, or (b) the magnesium ion content of aqueous solution B is 0.1 mol / L to 5.7 mol / L and the calcium ion content is 0.5 mmol / L to 6.7 mol / L. (20) The method according to (18) or (19) above, wherein aqueous solution B further contains sodium ions and / or potassium ions.

[0020] (21) A cosmetic treatment method, excluding medical procedures, comprising applying to skin or hair a cosmetic preparation produced by the method described in any one of (1) to (9) above or containing the nanoparticles described in (10) or (11) above. (22) A cosmetic treatment method, excluding medical procedures, comprising applying to skin or hair an aqueous composition produced by the method described in (16) above.

[0021] (23) The cosmetic treatment method according to (21) or (22), further comprising applying a solution containing one or more types of trivalent metal ions to the skin or hair. (24) A method for producing a polyanionic hydrogel, comprising: a first step of obtaining a polyanionic nanoparticle dispersion using the method according to any one of (1) to (9) above; and a second step of applying the polyanionic nanoparticle dispersion to a substrate and drying it to produce a polyanionic hydrogel.

[0022] (25) The method according to (24) above, further comprising a third step of reacting a trivalent metal ion with the polyanionic hydrogel. (26) The method according to (25), wherein the reacting a trivalent metal ion with the polyanionic hydrogel comprises contacting a solution containing one or more types of trivalent metal ions with the hydrogel film on the substrate or the hydrogel permeated into the substrate.

[0023] (27) The trivalent metal ion is Fe 3+ and Al 3+ (28) A hydrogel or hydrogel film obtained by the method according to any one of (24) to (27) above.

[0024] (29) A cosmetic treatment method in which hyaluronic acid nanoparticles are applied to the skin or keratinous substrates such as hair and nails to directly prepare or form a hydrogel film, excluding medical procedures. (30) A method in which a hydrogel film is applied to the skin or keratinous substrates such as hair and nails to directly prepare or form a hydrogel film, excluding medical procedures. 3+ and / or Al 3+ The cosmetic treatment method according to (29) above, wherein the elasticity of the hydrogel film is adjusted by treating the film with a solution containing:

[0025] The polyanionic nanoparticles obtained by the present invention can maintain their particulate form while dispersed in a liquid composition, making them suitable for incorporation into external skin preparations, including cosmetics and quasi-drugs. The polyanionic nanoparticles obtained by the present invention are fine particles with a particle diameter of 600 nm or less, and therefore have excellent penetration into skin and hair, making them useful in the treatment and / or care of skin, hair, and nails. In the production method of the present invention, mechanical severing of the polymer chains of the polyanionic nanoparticles further reduces their particle size and the viscosity of liquid compositions containing the polyanionic particles, making them suitable for use in cosmetics to be sprayed from a spray container, for example.

[0026] When the polyanionic nanoparticles of the present invention are dried, the divalent metal ions act as dynamic crosslinkers to form a water-resistant polyanionic hydrogel film, which has the ability to self-regenerate in the presence of water.

[0027] Furthermore, the elasticity of the hydrogel film formed from these nanoparticles can be controlled by adding trivalent metal ions to the film, resulting in a more elastic hydrogel.

[0028] After hyaluronic acid nanoparticles have penetrated the skin, treatment with trivalent metal ions can further crosslink the hyaluronic acid nanoparticles in the stratum corneum, resulting in skin lift and firmness. Furthermore, it can also reduce dark circles under the eyes, solving other skin problems.

[0029] This shows an example of a hydrogel film formed on a glass substrate. This shows the water resistance of hyaluronic acid hydrogel. This shows the self-regenerating ability of hyaluronic acid hydrogel. This shows the penetration of hyaluronic acid nanoparticles into cultured epidermis. This is an explanatory diagram showing the nanoparticle formation of hyaluronic acid using metal ions. This is a microscopic image showing the effect of treatment using hyaluronic acid nanoparticles. A comparison is made between the before treatment (photograph on the left) and the after treatment (photograph on the right). Hyaluronic acid nanoparticles and trivalent metal ions (Fe ３＋ and Al ３＋This shows the effect of using the combined use of Solution B, which contains hyaluronic acid nanoparticles. The order of application is different in the upper and lower figures. Regardless of the order of application, an improvement in skin firmness and luster was observed after treatment (photo on the right) compared to before treatment (photo on the left). This shows the results of underwater AFM observation of hyaluronic acid nanoparticles. The left is a top-view AFM image with height contrast, and the right is an elasticity image acquired at the same time.

[0030] Figure 5 shows a schematic diagram of nanoparticle formation of polyanions (hyaluronic acid is used as an example) using metal ions. Hyaluronic acid has a negative charge in aqueous solution due to the presence of carboxyl groups. Due to electrostatic repulsion based on this negative charge, linear polymers in the hyaluronic acid aqueous solution are fully extended, resulting in large molecular sizes and increased viscosity due to entanglement. ２＋ and Ca ２＋ When these two molecules are combined, ionic bonds form within the molecule to form nanometer-sized particles.

[0031] The invention disclosed herein relates to the production of polyanionic nanoparticles, also known as anionic polymers, using at least two types of metal cations.

[0032] A. Polyanion (anionic polymer) (1) Hyaluronic acid or its salt Hyaluronic acid is an acidic mucopolysaccharide with a repeating structural unit of disaccharides of N-acetyl-D-glucosamine and D-glucuronic acid. There is no particular limitation on the hyaluronic acid that can be used to form nanoparticles according to the present invention. Hyaluronic acid can be extracted and purified by conventional methods from animal tissues such as rooster comb, vitreous body of oxeye, and umbilical cord. It can also be produced by culturing a microorganism that produces hyaluronic acid, that is, by the so-called fermentation method. In the present invention, hyaluronic acid can be obtained by any method, and can be extracted and produced by oneself or commercially available products.

[0033] Preferably, the hyaluronic acid is a water-soluble salt. Examples of water-soluble salts of hyaluronic acid include alkali metal salts such as sodium and potassium. From the viewpoint of versatility and availability, sodium hyaluronate (Na hyaluronate) is preferred. Currently, it is generally obtained by fermentation using lactic acid bacteria Streptococcus zooepidemicus or Streptococcus equi. Sodium hyaluronate is represented by the following chemical formula:

[0034]

[0035] Sodium hyaluronate may be hydrolyzed sodium hyaluronate or sodium hyaluronate in which some of the substituents have been acetylated. Commercially available sodium hyaluronate is readily available to those skilled in the art. Sodium hyaluronate may be used alone or in combination of two or more types. There is no particular restriction on the molecular weight of the sodium hyaluronate that can be used in the present invention, but in cosmetics, sodium hyaluronate with an average molecular weight (GPC) of 10,000 to 2,000,000 is mainly used.

[0036] (2) Xanthan gum Xanthan gum is generally incorporated into cosmetics as a binder, hydrophilic thickener, emulsion stabilizer, emulsifier, skin conditioning agent, etc. Xanthan gum is a polysaccharide composed of repeating units with a main chain of two glucose units, represented by the following chemical formula, and one glucuronic acid and two mannose units bonded to the side chains.

[0037]

[0038] Xanthan gum is obtained by fermenting carbohydrates with Xanthomonas campestris. There are no particular limitations on the xanthan gum that can be used to form nanoparticles according to the present invention. Commercially available xanthan gums are readily available to those skilled in the art. Xanthan gum may be used singly or in combination.

[0039] (3) Sodium Chondroitin Sulfate Sodium chondroitin sulfate, like sodium hyaluronate, is a sodium salt of an acidic mucopolysaccharide that is used in cosmetics for its moisturizing effect by retaining moisture on the skin surface. Sodium chondroitin sulfate is a sodium salt of a glycosaminoglycan (mucopolysaccharide) composed of repeating units of a linear chain of N-acetyl-D-galactosamine (see the right diagram below; when "R: SO3Na and R': H" it becomes N-acetyl-D-galactosamine tetrasulfate, and when "R: H and R': SO3Na" it becomes N-acetyl-D-galactosamine hexasulfate) with a sulfate group (-SO4) attached to the 4th or 6th position, as shown in the chemical formula below, and uronic acid (see the left diagram below).

[0040]

[0041] There are no particular limitations on the sodium chondroitin sulfate that can be used to form nanoparticles according to the present invention. Commercially available sodium chondroitin sulfate is readily available to those skilled in the art. Sodium chondroitin sulfate may be used alone or in combination of two or more types.

[0042] (4) Dextran Sulfate Sodium dextran sulfate is a sodium salt of sulfate ester obtained by sulfating the partial hydrolysis product of dextran, a glucose polymer. Dextran is produced by sucrose fermentation, typically by partially hydrolyzing high-molecular-weight dextran produced by Leuconostoc mesenteroides, a type of lactic acid bacteria, followed by fractionation and purification processes. Dextran sulfate sodium is generally used in skin conditioners and cosmetics for its moisturizing effect and the expected effect of improving peripheral blood flow. There are no particular limitations on the dextran sulfate sodium that can be used to form nanoparticles according to the present invention. Commercially available dextran sulfate sodium is readily available to those skilled in the art. Dextran sulfate sodium may be used alone or in combination.

[0043] (5) Tremella Fuciformis Polysaccharide Tremella fuciformis polysaccharide is obtained by extraction with water, ethanol, BG, or a mixture thereof from the fruiting bodies of the Tremella fuciformis (scientific name: snow fungus), a basidiomycete fungus belonging to the Tremella family. It is a complex polysaccharide typically consisting of a repeating unit in which nine mannose units are linked together via α-1,3 bonds in the main chain, to which D-fucose, D-xylose, and D-glucuronic acid are linked in a 1:4:3 ratio in the side chains. Tremella fuciformis polysaccharide is highly soluble in water and has high water retention and viscosity. There are no particular limitations on the Tremella fuciformis polysaccharide that can be used to form nanoparticles according to the present invention. Commercially available Tremella fuciformis polysaccharides are readily available to those skilled in the art. Tremella fuciformis polysaccharides may be used singly or in combination.

[0044] B. Minerals (Metal-Derived Cations) In the present invention, aqueous solution B used to produce polyanionic nanoparticles is also referred to as "minerals." In the present invention, "minerals" refers to aqueous solutions containing cations derived from two or more different metals. The minerals preferably contain alkaline earth metal salts. The minerals preferably contain divalent metal ions. The minerals preferably contain monovalent and divalent metal ions. The minerals preferably do not contain iron ions. The minerals preferably contain at least Mg ions and Ca ions, with the Mg ion content being, for example, 0.1 mol / L to 5.7 mol / L and the Ca ion content being, for example, 0.5 mmol / L to 6.7 mol / L. The minerals may further contain either Na ions or K ions, or both. While the minerals preferably have a complex composition, such as bittern or CSWII (seawater concentrate), they do not necessarily have to be naturally derived and may be artificially synthesized. In a preferred embodiment, bittern or CSWII (seawater concentrate) can be used after appropriate dilution.

[0045] (1) Nigari (Bittern) Generally, "bittern" refers to the liquid remaining after removing salt from seawater, and has long been widely used as a tofu coagulant. The Kojien dictionary defines "bittern" as "the mother liquor remaining after boiling and purifying seawater." Bittern can be roughly thought of as seawater that has been concentrated 30 to 40 times and most of the sodium chloride removed. Therefore, it is thought that the trace minerals in seawater are concentrated and present in nigari. As a food additive, it is called "crude magnesium chloride from seawater," also known as "crude magnesium chloride from seawater," and is defined as "a substance whose main component is magnesium chloride obtained by precipitating and separating sodium chloride and potassium chloride from seawater."

[0046] (2) Seawater concentrate The seawater concentrate is a deep seawater concentrate described in Japanese Patent No. 5500757, and can be obtained by the manufacturing method described in claim 1 of the patent document. That is, the deep-sea water concentrate can be obtained by a production method including the following steps (1) and (2): (1) treating deep-sea water with a nanofilter membrane capable of removing 90% or more of sulfate ions to obtain NF membrane permeate having a Brix of 2.8 to 3.6, a Mg ion concentration of 300 to 900 mg / L, a Ca ion concentration of 200 to 600 mg / L, and a SO ion concentration of 0 to 300 mg / L; and (2) concentrating the NF membrane permeate obtained in step (1) to obtain an NF membrane permeate concentrate having a Brix of 30.0 to 55.0, a Mg ion concentration of 10,000 to 100,000 mg / L, a Ca ion concentration of 4,000 to 40,000 mg / L, and a SO ion concentration of 0 to 1,000 mg / L, and a Ca ion concentration:Mg ion concentration ratio of 1:0.25 to 1:4. A specific example of a deep seawater concentrate is "Condensed Seawater II (CSW II)," an original ingredient of the applicant (Wamiless Cosmetics Co., Ltd.).

[0047] (3) Composition of Minerals Examples of the composition of metal ions contained in minerals that can be used in the present invention are given below.

[0048]

[0049]

[0050] (4) Artificially synthesized mineral mixtures of reagents, such as those prepared by mixing common salts such as magnesium chloride, calcium chloride, sodium chloride, and potassium chloride, can also be suitably used. Further examples of usable reagent salts are as follows:

[0051] In addition to magnesium chloride, salts that can be used to supply magnesium ions (Mg ions) include magnesium sulfate, magnesium carbonate, magnesium silicate, magnesium phosphate, and organic magnesium salts such as magnesium lactate, magnesium hyaluronate, magnesium ascorbyl phosphate, and magnesium citrate.

[0052] Salts used to supply calcium ions (Ca ions) include calcium chloride, as well as calcium sulfate, calcium bromide, calcium acetate, calcium phosphate, calcium carbonate, calcium silicate, calcium nitrate, calcium hydroxide, and organic calcium acids such as calcium lactate, calcium citrate, calcium gluconate, and calcium succinate.

[0053] In addition to sodium chloride, salts used to supply sodium ions (Na ions) include sodium sulfate, sodium bicarbonate, sodium carbonate, sodium hydroxide which has a pH adjusting function, and organic sodium acids such as sodium lactate, sodium citrate, sodium gluconate, and sodium succinate.

[0054] In addition to potassium chloride, salts used to supply potassium ions (K ions) include potassium sulfate, potassium carbonate, potassium aluminum sulfate, and organic potassium salts such as potassium lactate, potassium dihydrogen phosphate, potassium chondroitin sulfate, potassium hyaluronate, and dipotassium glycyrrhizinate.

[0055] It is also possible to use naturally occurring ion-containing aqueous solutions such as deep sea water as part of the raw materials and adjust the composition to the desired level using the various salts mentioned above.

[0056] Ratio of Charge Number of Divalent Metal Cations to Charge Number of Polyanions (Cation / Anion Ratio) In this application, the ratio of the total charge number contained in the divalent metal cations of minerals to the total charge number of the polyanions is referred to as "charge number of divalent metal cations / charge number of polyanions" or "cation / anion ratio." This ratio is the ratio of the charge number of cations to the charge number of anions after mixing aqueous solutions A and B. The inventors have found that the cation / anion ratio affects the size of polyanionic nanoparticles. The charge number of cations must be in excess of the charge number of anions, i.e., the cation / anion ratio must be greater than 1. As the cation / anion ratio increases, the average particle size of polyanionic nanoparticles tends to decrease. Representative examples of divalent cations include divalent metal ions such as Mg ions and Ca ions.

[0057] The "anionic charge number," which is the number of charges on a polyanion, is calculated using the following formula: Anionic charge number = amount of anionic polymer (g) x (number of anionic functional groups / molecular weight of polyanion repeating unit (g / mol)) For example, if the anionic polymer is sodium hyaluronate, the molecular weight of the monomer consisting of one molecule each of N-acetylglucosamine and glucuronic acid bonded together is used as the repeating unit molecular weight of 401 (g / mol).

[0058] The "cation charge number," which is the number of charges on divalent metal cations, is calculated using the following formula: Cation charge number = mineral amount (g) x (divalent metal cation concentration (mol / L) x number of charges)

[0059] The "ratio of the number of charges on the divalent metal cation to the number of charges on the polyanion" or "cation / anion ratio" is calculated using the following formula: Cation / anion ratio = number of charges on the cation / number of charges on the anion

[0060] In Example 9 described below, by setting the cation / anion ratio to 2, even when the concentration of the polyanion hyaluronic acid was increased to 0.35 (w / w)%, polyanionic nanoparticles with a particle size of about 600 nm could be obtained. In Example 10, even when the cation / anion ratio was reduced to 1.1, if the concentration of the polyanion hyaluronic acid was 0.1 (w / w)%, polyanionic nanoparticles with a particle size of about 600 nm could be obtained. As described below, by undergoing a process of cutting the polymer chain of the polyanion by mechanical force, the particle size can be further reduced to 500 nm or less.

[0061] Therefore, in the present invention, the upper limit of the polyanion concentration is 0.35 (w / w)%. The polyanion concentration can be preferably 0.27% or less, more preferably 0.22% or less. For example, the polyanion concentration can be 0.01 to 0.35%. The lower limit of the cation / anion ratio is 1.1. The cation / anion ratio can be preferably 1.2 or more, more preferably 1.3 or more.

[0062] Particle size of nanoparticles In the present invention, the average particle size of polyanion nanoparticles can be, for example, 600nm or less, or 500nm or less, or 400nm or less, or 300nm or less.Here, the average particle size refers to the Z-average particle size of hyaluronic acid particles, which is optically measured by dynamic light scattering, assuming that the particle shape of hyaluronic acid particles is spherical.This average particle size can be measured, for example, using an instrument such as Malvern Zetasizer Nano ZSP.Since the particle size is measured by dynamic light scattering, it is measured indirectly, not directly.

[0063] In contrast, there are methods for directly observing particles. Scanning probe microscopes (SPMs), such as scanning tunneling microscopes (STMs) and atomic force microscopes (AFMs), allow for the observation of individual particles. See the photograph in Figure 8 for an example.

[0064] Micronization by Mechanical Force The particle size can be further reduced by mechanically cutting the polymer chains of polyanionic nanoparticles obtained by stirring and mixing aqueous solution A containing polyanions and aqueous solution B containing minerals. The cutting of polymer chains by mechanical force is carried out while the polyanionic nanoparticles obtained by stirring and mixing aqueous solutions A and B remain suspended in the liquid. Methods that can be used to mechanically cut the polymer chains of polyanionic nanoparticles include mastication, ultrasonic waves, high-speed stirring, spraying, capillary flow, bead milling, and impact by collision. In particular, it is preferable to use a high-pressure dispersion device that can cause pressurized particles to collide with each other in a liquid to achieve micronization. An example of such a device is the Star Burst wet atomization device manufactured by Sugino Machine. （登録商標） ) are listed.

[0065] Polyanion Hydrogel Film Functional hydrogels can be produced by applying polyanion nanoparticles to a substrate and drying them. Functionality includes water retention, water resistance, and self-regenerating ability. These functions are advantageous when using polyanion hydrogels in cosmetics. Water resistance makes the hydrogel less likely to come off in water. Self-regenerating ability means that even if the hydrogel is scratched, the hydrogel film will regenerate and repair itself with humidity, sweat, etc. These functions ensure long-lasting water retention.

[0066] While not intending to be bound by theory in the interpretation of the present invention, the following may be hypothesized as a mechanism for hydrogel formation and functionality. Divalent metal cation minerals act as crosslinkers for polyanions to form polyanion nanoparticles, which are further concentrated upon drying, increasing the concentrations of polyanions and divalent metal cations and forming a hydrogel film. Therefore, while polyanions (e.g., hyaluronic acid) alone would dissolve in water, the crosslinking by divalent mineral ions renders them less soluble in water, imparting water resistance (see the schematic diagram on the right of Figure 2). Furthermore, because divalent metal ions are dynamic crosslinkers, when the cut surfaces of a hydrogel (film) cut in two are lightly wetted and brought into contact with water, the crosslinks recombine, resulting in self-regeneration of the hydrogel.

[0067] It is known that when polyanions such as hyaluronic acid are mixed with trivalent metal ions, they do not form nanoparticles but form macroscopic hydrogels (Non-Patent Document 1). (Note that, in the present invention, divalent metal ions are suitable for forming nanoparticles.)

[0068] Therefore, the present inventors first prepared a hydrogel by coating and drying nanoparticles formed from divalent metal ions and polyanions (e.g., hyaluronic acid), and then further added trivalent metal ions (e.g., Fe ３＋ , Al ３＋ We found that the addition of trivalent metal ions accelerated gelation and resulted in the formation of more elastic gel films. This result indicates that the elastic modulus of the hydrogel film can be controlled by trivalent metal ions, which is an additional advantage when using polyanionic hydrogels in cosmetics.

[0069] A further aspect of the invention disclosed herein relates to a method for preparing a polyanionic hydrogel, which includes a first step of forming polyanionic nanoparticles by the method described above to obtain a nanoparticle dispersion, and a second step of applying the obtained nanoparticle dispersion to a substrate and drying it to prepare a polyanionic hydrogel.

[0070] The method for preparing the polyanionic hydrogel may further include a third step of reacting trivalent metal ions with the polyanionic hydrogel to further promote gelation. Here, "acting" refers to reacting one or more types of trivalent metal ions (e.g., Fe) with the hydrogel film on the substrate or the hydrogel permeated into the substrate. ３＋ , Al ３＋ ) (for convenience, we will refer to this solution as solution B2, solution B2, and Fe 3+ ・Al 3+ The method includes adding a solution containing trivalent metal ions (sometimes referred to as Solution B containing Fe3+, etc.) to the hydrogel film, thereby bringing the trivalent metal ions into contact with the hydrogel film. A suitable example of a solution containing trivalent metal ions is Skin Refresher Solution B (Fe3+ concentration: 1 mmol / L) from Wamiles Cosmetics, but it is not limited to this. The Yunohana extract described in Patent No. 3967357 may also be used after being appropriately diluted. The solution containing trivalent metal ions is preferably a solution containing iron ions (Fe ３＋ ) and / or aluminum ions (Al ３＋ ), and preferably contains both iron ions and aluminum ions.

[0071] In the method for preparing the polyanionic hydrogel of the present invention, the substrate may be a non-absorbent substrate such as the glass slide used in the examples described below, or a body surface such as skin, hair, or nails. On a glass plate, a removable film-like hydrogel can be formed. In contrast, when polyanionic nanoparticles are applied to the skin, some of the polyanionic nanoparticles penetrate into the skin, while others remain on the epidermis and dry to form a hydrogel on the skin.

[0072] Use of Polyanionic Nanoparticles in Cosmetic Treatments Another aspect of the invention disclosed herein relates to cosmetic preparations containing polyanionic nanoparticles, as well as cosmetic treatment methods (also referred to as cosmetic treatment methods) that involve applying polyanionic nanoparticles to skin or hair.

[0073] In a penetration experiment using cultured epidermis, it was confirmed that both hyaluronic acid nanoparticles and high-pressure-treated hyaluronic acid nanoparticles penetrated the stratum corneum. The high-pressure-treated hyaluronic acid penetrated in greater amounts and penetrated deeper into the stratum corneum. Therefore, high-pressure treatment may or may not be used in the manufacturing process of polyanionic nanoparticles used in cosmetics and beauty treatments.

[0074] The form of the cosmetic containing polyanionic nanoparticles is not particularly limited, but it is generally thought that it is used by applying it to the skin or hair, and it can be in any form such as lotion, cream, gel, mousse, spray, etc. Use by topical application for cosmetic purposes also includes application to the skin or hair and then rinsing it off. As the polyanionic nanoparticles for cosmetic use, hyaluronic acid nanoparticles are preferred, but other polyanions can also be used.

[0075] The cosmetic of the present invention can be used in cosmetic treatments performed by the user or by another person, such as an esthetician. The cosmetic treatment may be performed in a salon or at home. The cosmetic is preferably applied to the skin or hair, and application methods include, but are not limited to, application by hands or fingers, impregnation into nonwoven fabric, and application by spray spray. Any method commonly used in cosmetic treatments can be used depending on the form of the cosmetic.

[0076] The cosmetic of the present invention can be appropriately blended with various commonly used cosmetic ingredients (oils and fats, waxes, hydrocarbons, fatty acids, alcohols, esters, amino acids, vitamins, surfactants, pH adjusters, preservatives, fragrances, moisturizers, powders, ultraviolet absorbers, thickeners, pigments, antioxidants, whitening agents, anti-inflammatory agents, anti-wrinkle agents, agents for improving rough skin, anti-acne medications, alkalis, chelating agents, sequestering agents, etc.) within a range that does not impair the desired effects.

[0077] The cosmetic of the present invention may also contain substances derived from natural products. Examples of such substances include: plum extracts, such as plum root extract and plum fruit distilled water, as described in Japanese Patent No. 4795475; plum juice fermentation liquid, as described in Japanese Patent No. 2526362; steam-distilled water derived from plants, as described in Japanese Patent Application Laid-Open No. 2012-116761, such as steam-distilled water from one or more plants selected from passion fruit, mandarin orange, banana, atemoya, plum, tankan, lemon lime, and ginger; angelica extract, as described in Japanese Patent Application Laid-Open No. 3544505; and seawater-derived yeast culture, as described in Japanese Patent Application Laid-Open No. 2009-029788.

[0078] Cosmetic treatment method using hyaluronic acid nanoparticles and trivalent metal ions in combination After hyaluronic acid nanoparticles are penetrated into the skin, trivalent metal ions (e.g., Fe 3+ and Al 3+ By applying a solution containing hyaluronic acid hydrogel, it is possible to further crosslink the hyaluronic acid hydrogel that has penetrated the stratum corneum, making it more elastic.

[0079] In addition, the nanoparticles that did not penetrate into the skin and remained on the epidermis turned into a hydrogel on the skin by drying, and Fe ３＋ and Al ３＋ These hydrogels also become more elastic when applied with a solution containing , meaning that the elastic modulus of the hydrogel both in and on the skin can be controlled.

[0080] The nanoparticles of the present invention can be used in any form of cosmetic preparation, such as lotion, cream, gel, mousse, spray, etc.

[0081] The present invention will be specifically described below with reference to examples. Note that these examples are for the purpose of illustrating the present invention and are not intended to limit the scope of the present invention.

[0082] Examples 1 to 8, 19 and Comparative Examples 1 to 4 As shown in Table 1, various combinations of component A (aqueous polyanion solution) and component B (mineral) were tested. A was weighed into a beaker and heated to 70°C with a magnetic stirrer while stirring to dissolve the polyanion. B was added to A, and the mixture was cooled to room temperature while stirring. The appearance and particle size were evaluated. The appearance was observed visually, and the z-average particle size (d.nm) was measured using a Malvern Zeta Thermo Nano ZSP.

[0083] Table 1: Combinations

[0084]

[0085] The hyaluronic acid used in the examples was sodium hyaluronate obtained by lactic acid bacteria fermentation (manufacturer: Kikkoman Biochemifa Corporation). In the comparative examples (1-4) and examples 1 and 2, hyaluronic acid (FCH200) with a molecular weight of 1.8 million to 2.2 million was tested.

[0086] In Examples 7 and 8, hyaluronic acid with different molecular weights, namely, hyaluronic acid with a molecular weight of 1.4 million to 1.8 million (FCH150) and hyaluronic acid with a molecular weight of 500,000 to 700,000 (FCH60), were used in the tests.

[0087] In Examples 3-6 and 19-20, polyanions other than hyaluronic acid were tested. Dextran Sulfate Sodium (DST-H) and Dextran Sulfate Sodium (DSV-H) are sodium salts of sulfonated dextran, with average molecular weights of approximately 1500-2400 and approximately 500,000-700,000, respectively (manufacturer: Meito Sangyo Co., Ltd.). Xanthan gum (Keltrol CG-SFT) and sodium chondroitin sulfate are also commercially available products.

[0088] It was shown that no particles were obtained in Comparative Example 1, in which component B (mineral) was not added, and that the particle size decreased in all other examples in which a metal salt (mineral) was added.

[0089] The results of Comparative Examples 2 to 4 show that combining metal salts (minerals) of a single composition reduces particle size, but not sufficiently. The results of Examples 1 and 2 show that a mixture with minerals of complex composition (two or more types of divalent metal salts) can significantly reduce particle size. Bittern was used as the mineral in Example 1, and seawater concentrate was used in Example 2.

[0090] The results of Examples 3 to 8 and 19 to 20 showed that by using seawater concentrate as a mineral, hyaluronic acid with different molecular weights and polyanions other than hyaluronic acid can be nanoparticled, and that nanoparticles can also be formed even when hyaluronic acid and polymers other than hyaluronic acid coexist (Example 20).

[0091] <Examples 9 and 10> Based on the combination of Example 2 (Component A: phenoxyethanol 0.5%, hyaluronic acid (FCH200) 0.2%; Component B: seawater concentrate 0.14%; cation / anion ratio: 1.782; average particle size: 474 nm), tests were conducted by changing the hyaluronic acid concentration and cation / anion ratio, and the appearance and particle size were evaluated. Representative examples are shown in Table 2.

[0092] Table 2. Concentrations and ratios

[0093]

[0094] The results of Example 9 show that particles with an average particle size of 599 nm can be obtained even when the hyaluronic acid concentration is increased up to 0.35%, which is the upper limit of the hyaluronic acid concentration (polyanion concentration).

[0095] The results of Example 10 show that particles with an average particle size of 577 nm can be obtained even when the cation / anion ratio is reduced to 1.1, which is the lower limit of the cation / anion ratio.

[0096] Examples 11 to 13 and Example 21 The nanoparticles obtained in Example 2 were subjected to a polyanionic polymer chain scission treatment using mechanical force. Using different scission conditions, the appearance (visual observation), particle size, and viscosity were evaluated.

[0097] Table 3. Conditions for polymer chain scission by mechanical force

[0098]

[0099] In Examples 11 to 13, a high-pressure dispersion device (Starburst manufactured by Sugino Machine) was used. In Example 21, an ultrasonic dispersion device (ultrasonic homogenizer manufactured by AS ONE) was used. The results of Examples 11 to 13 and Example 21 showed that cutting the polymer chains by mechanical force can further reduce the particle size and also reduce the viscosity of the solution.

[0100] Example 14 and Comparative Example Example 14: Formation of a hydrogel film by drying hyaluronic acid nanoparticles Hyaluronic acid nanoparticles were prepared using the ratio of hyaluronic acid to seawater concentrate shown in Table 4 below.

[0101] 0.5 g of this nanoparticle dispersion was applied to a glass slide and dried to prepare a hydrogel film composed of nanoparticles (Example 14 in Figure 1). In order to fluorescently label the hyaluronic acid nanoparticles shown in Table 4, 0.01% fluorescently labeled hyaluronic acid (manufactured by Iwai Chemicals Co., Ltd.) was added to the hyaluronic acid nanoparticles during their preparation, to prepare fluorescently labeled hyaluronic acid nanoparticles (Table 5).

[0102] A hydrogel film formed from nanoparticles was prepared by applying 0.5 g of this nanoparticle dispersion to a glass slide and drying it. After rinsing the hydrogel film with water and drying it, the glass slide was observed under a fluorescence microscope, revealing that a fluorescent hydrogel film remained on the substrate (Figure 2). This confirmed the formation of a water-resistant hyaluronic acid gel film.

[0103] A hydrogel composed of hyaluronic acid nanoparticles was prepared using 3 g of the nanoparticle dispersion in Table 5 (Figure 3). After dividing the gel into two equal parts with a spatula, the cut surfaces were lightly wetted with water and the two gel pieces were brought into contact with each other. The two gel pieces fused at the fractured surfaces. This demonstrated that the hydrogel composed of hyaluronic acid nanoparticles has the ability to self-regenerate.

[0104] Comparative Example A: A solution was prepared by removing only the seawater concentrate from the formulation shown in Table 5, and the solution was applied to a glass substrate and dried to form a hydrogel film consisting only of hyaluronic acid (Table 6).

[0105] When this hydrogel film was washed with water and dried, it was observed under a fluorescence microscope, and no fluorescence was detected (Figure 2). This result confirmed that the hyaluronic acid hydrogel film made without using seawater concentrate was not water resistant.

[0106] Comparative Example B: A macroscopic hydrogel was prepared using the hydrogel film consisting only of hyaluronic acid prepared in Comparative Example A, and then cut into two equal parts with a spatula. The cut surfaces were lightly wetted with water, and the two gel pieces were brought into contact with each other, but the two gel pieces did not fuse.

[0107] Example 15: Formation of a hydrogel film by drying high-pressure-treated nanoparticles The nanoparticles obtained in Example 14 were dispersed using a high-pressure dispersion device (Starburst manufactured by Sugino Machine). The dispersion conditions were 150 MPa. Smaller nanoparticles were produced compared to Example 14. Z-average particle size (d.nm): 140 nm Viscosity (mPa·s): 3.7 mPa·s A hydrogel film formed from high-pressure-treated nanoparticles was produced by applying 0.5 g of this high-pressure-treated nanoparticle dispersion to a glass slide and drying it (Example 15 in Figure 1).

[0108] The fluorescently labeled hyaluronic acid nanoparticles prepared in Table 6 were subjected to high-pressure treatment at 150 MPa to produce a high-pressure treated fluorescently labeled hyaluronic acid nanoparticle solution (Z-average particle size (d nm): 339 nm, viscosity (mPa s): 3.5 mPa s). 3 g of this solution was dried to produce a hydrogel, and the self-regenerating ability test was performed using the same method as above, demonstrating self-regenerating ability.

[0109] Example 16 and Comparative Example Example 16: Fe nanoparticle hydrogel film 3+Further crosslinking by WAMIRES Cosmetics' Skin Refresher B liquid (Fe 3+ When 10 μl of FeCl3 solution (Fe 3+ The same results were obtained when Al2(SO4)3 solution and potassium alum (KAl(SO4)2) solution were used (both containing Al 3+ The concentration of 1mmol / L also improved the elasticity of the hydrogel film. The following reagents were used: Iron(III) chloride hexahydrate (WAKO) Aluminum sulfate 14-18 hydrate (WAKO)

[0110] Comparative example: Divalent ion Mg 2+ , Ca 2+ , a monovalent ion, Na + , K + was prepared using MgCl2, CaCl2, NaCl, and KCl to a concentration of 1 mmol / L, and 10 μl of the solution was added dropwise to the hydrogel and mixed, but no further increase in the elastic modulus was observed.

[0111] Example 17 and Comparative Example Example 17: Penetration of hyaluronic acid nanoparticles into cultured epidermis Cultured epidermis (J-TEC, LabCyte EPI-MODEL12) was punched out of a cup and allowed to stand at room temperature. After pre-incubation for at least 1 hour, 200 μL each of the fluorescently labeled hyaluronic acid nanoparticle solution prepared in Table 6 and hyaluronic acid nanoparticles prepared by high-pressure treatment of the same were applied to the stratum corneum side. After 18 hours, the cultured epidermis was rinsed three times with PBS (500 μL). The cultured epidermis was embedded in OCT compound (Sakura Finetech Japan), frozen, and frozen sections were prepared and observed under a fluorescence microscope.

[0112] It was shown that both hyaluronic acid nanoparticles and high-pressure-treated hyaluronic acid nanoparticles penetrated into the cultured epidermis (Figure 4). Comparative example: Hyaluronic acid alone, not nanoparticles, did not penetrate into the cultured epidermis (Figure 4).

[0113] <Example 18 and Comparative Example> Example 18: Treatment method using hyaluronic acid nanoparticles When 1 ml of the hyaluronic acid nanoparticle dispersion of Example 14 was sprayed onto half of the face, the skin felt firm and shiny, and when observed under a microscope, it was confirmed that fine irregularities were formed and the skin texture was refined (Figure 6). 3+ and Al 3+ When the B liquid (Skin Refresher B) containing hyaluronic acid nanoparticle dispersion was applied in layers, the firmness and luster of the skin were further improved, and when observed under a microscope, the texture was found to be even finer (Figure 7). Furthermore, after two weeks of continued use, the dark circles under the eyes became lighter. Furthermore, after applying and drying the hyaluronic acid nanoparticles, the above-mentioned Fe 3+ and Al 3+ When I applied Solution B (Skin Refresher B) containing the ingredients to half of my face, I felt my skin become firmer, and after using it for a week, my cheeks were lifted.

[0114] <Examples using other polyanions> When nanoparticles of xanthan gum (Keltrol CG-SFT), dextran sulfate sodium (DSV-H), and chondroitin sulfate sodium were used, hydrogel (film) formation and further crosslinking with trivalent ions were possible, similar to hyaluronic acid nanoparticles.

[0115] Observation of Polyanion Nanoparticles Using a NanoScopeV Dimension Fast Scan Bio scanning probe microscope (SPM), underwater AFM observation of hyaluronic acid nanoparticles was performed using the peak force tapping method with a SiN cantilever under the following conditions: Measurement environment: room temperature, underwater (Milli-Q water) Substrate: smooth surface of PMMA plate (HD6) Scanning range: 2 μm Observation: observed 22 minutes after sample addition Hyaluronic acid nanoparticle composition: sodium hyaluronate (molecular weight 2 million) 0.2% Seawater concentrate (CSW2) 0.14% Preservative (phenoxyethanol) 0.5% Water QS to 100% Mechanical cutting conditions: Apparatus: Starburst Mini (Sugino Machine Co., Ltd.) Pressure: 150 MPa The left side of Figure 8 is a top-view AFM image, with bright areas indicating higher elevations. Many nanoparticles of approximately 50 nm in size (circled numbers 3, 4, 7, and 8) were observed, as well as sheet-like structures of approximately 200 nm in size (circled numbers 1, 2, and 6), which are thought to have aggregated and changed shape due to adsorption to the hydrophobic PMMA substrate. Structures in which some hyaluronic acid nanoparticles were attached to each other (circled numbers 2 and 5) were also observed. The image on the right of Figure 8 is an elastic modulus image, and areas with lower elastic modulus appear darker. It can be seen that the areas where nanoparticles were adsorbed in the image on the left have a lower elastic modulus than the PMMA substrate.

Claims

1. A method for producing polyanion nanoparticles, comprising mixing with stirring an aqueous solution A containing a polyanion and an aqueous solution B containing at least two types of divalent metal cations.

2. The method of claim 1, wherein the polyanion of aqueous solution A is one or more anionic polymers selected from hyaluronic acid or a salt thereof, xanthan gum or a salt thereof, chondroitin sulfate or a salt thereof, dextran sulfate or a salt thereof, alginic acid or a salt thereof, carboxymethylcellulose or a salt thereof, or Tremella fuciformis polysaccharide or a salt thereof.

3. The method of claim 1, wherein aqueous solution B further comprises one or more monovalent metal cations.

4. The method according to claim 1, wherein the concentration of the polyanion after mixing aqueous solutions A and B is 0.35% (w / w) or less.

5. The method according to claim 1, wherein the ratio of the charge number of the divalent metal cation to the charge number of the polyanion after mixing aqueous solutions A and B is 1.1 or more.

6. The method of claim 1, wherein aqueous solution B is an aqueous solution containing bittern or CSWII (seawater concentrate).

7. The method of claim 1, further comprising the step of further reducing the particle size of the polyanionic nanoparticles.

8. The method of claim 1, wherein aqueous solution A further comprises a preservative.

9. The method of claim 1, wherein the polyanionic nanoparticles have a diameter of 600 nm or less.

10. Nanoparticles with a particle diameter of 600 nm or less, containing a polyanion and two or more types of divalent metal ions.

11. The nanoparticles according to claim 10, wherein the polyanion is one or more anionic polymers selected from hyaluronic acid or a salt thereof, xanthan gum or a salt thereof, chondroitin sulfate or a salt thereof, dextran sulfate or a salt thereof, alginic acid or a salt thereof, carboxymethylcellulose or a salt thereof, or Tremella fuciformis polysaccharide or a salt thereof.

12. Nanoparticles produced by the method of any one of claims 1 to 9 or according to claim 10 or 11.

13. The nanoparticles according to claim 12, which are cosmetic ingredients.

14. A method according to any one of claims 1 to 9 for producing an aqueous composition containing polyanionic nanoparticles.

15. The method of claim 7, wherein an aqueous composition containing polyanionic nanoparticles is produced with reduced viscosity.

16. A method for producing an aqueous composition containing polyanionic nanoparticles, comprising the steps of: stirring and mixing an aqueous polyanionic solution A and an aqueous solution B containing two or more types of divalent metal cations to form polyanionic nanoparticles; and mechanically severing the polymer chains of the resulting polyanionic nanoparticles.

17. The method according to claim 16, wherein the concentration of the polyanion after mixing aqueous solutions A and B is 0.01% to 0.35% (w / w) and the ratio of the charge number of the divalent metal cation to the charge number of the polyanion is 1.1 or more.

18. The method according to claim 16, wherein the divalent metal cations contained in aqueous solution B include at least magnesium ions and calcium ions.

19. The method according to claim 18, wherein the magnesium ion content of aqueous solution B is 0.1 to 5.7 mol / L and the calcium ion content is 0.0005 to 6.7 mol / L.

20. The method according to claim 18 or 19, wherein aqueous solution B further contains sodium ions and / or potassium ions.

21. A cosmetic treatment method (excluding medical procedures) comprising applying a cosmetic containing the nanoparticles according to claim 10 to the skin or hair.

22. A cosmetic treatment method (excluding medical procedures) comprising applying to skin or hair the aqueous composition produced by the method of claim 16.

23. A cosmetic treatment method according to claim 21 or 22, further comprising applying to the skin or hair a solution containing one or more trivalent metal ions.

24. A method for producing a polyanionic hydrogel, comprising: a first step of obtaining a polyanionic nanoparticle dispersion using the method according to any one of claims 1 to 9; and a second step of applying the polyanionic nanoparticle dispersion to a substrate and drying it to produce a polyanionic hydrogel.

25. The method of claim 24, further comprising a third step of reacting the polyanionic hydrogel with a trivalent metal ion.

26. The method of claim 25, wherein the step of reacting the polyanionic hydrogel with trivalent metal ions comprises contacting the hydrogel film on the substrate or the hydrogel impregnated within the substrate with a solution containing one or more types of trivalent metal ions.

27. The trivalent metal ion is Fe. ３＋ and Al ３＋ 27. The method of claim 26, wherein either one or both of 28. A hydrogel or hydrogel film obtainable by the method of claim 24.

29. A cosmetic treatment method in which hyaluronic acid nanoparticles are applied to the skin or hair to prepare or form a hydrogel film.

30. Hydrogel film with Fe ３＋ and / or Al ３＋ The cosmetic treatment method according to claim 29, wherein the elasticity of the hydrogel film is adjusted by treating it with a solution containing:

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