Paramylon particles, additive for epicutaneous agent, epicutaneous agent, and production method for paramylon particles

Abstract

Paramylon particles exhibiting a volume-based cumulative particle size distribution curve in which the 50% cumulative diameter (D50) and the 90% cumulative diameter (D90) are such that D50 is 1-10 µm, inclusive, and D90 / D50 is 3.0 or less.

Description

Paramylon particles, additives for topical skin preparations, topical skin preparations, and method for producing paramylon particles

[0001] The present invention relates to paramylon particles, an additive for a topical skin preparation, a topical skin preparation, and a method for producing paramylon particles.

[0002] Conventionally, microplastic beads such as methyl methacrylate crosspolymer particles have been used to improve the feel of cosmetics on the skin. For example, Patent Document 1 describes a UV light protection composition using methyl methacrylate crosspolymer. However, methyl methacrylate crosspolymer particles have the problem of low biodegradability and are a petroleum-derived compound. Therefore, in the cosmetics field, there has been a recent trend toward using raw materials derived from plants or living organisms from a sustainability perspective.

[0003] Meanwhile, in recent years, Euglena, a type of photosynthetic microorganism and a type of microalga, has attracted attention for producing substances with various health benefits, and paramylon, a polysaccharide contained in Euglena, is being investigated for use in the fields of pharmaceuticals, health foods, and the like (see Patent Documents 2 and 3).

[0004] JP 2003-206223 A JP 2021-193956 A JP 2023-076299 A

[0005] Paramylon is usually isolated from cultured Euglena cells and purified into fine particles for use. However, conventional paramylon particles tend to fuse together and form large clumps, which can cause stickiness and roughness when formulated into external skin preparations such as cosmetics.

[0006] Therefore, an object of the present invention is to provide paramylon particles that prevent fusion between particles and that, when formulated into a skin topical preparation, can reduce stickiness and roughness.

[0007] The present disclosure provides the following [1] to [9].

[0008] [1] Paramylon particles, in which, in a cumulative particle size distribution curve based on volume, the 50% cumulative diameter (D50) and the 90% cumulative diameter (D90) are D50 of 1 μm or more and 10 μm or less, and the D90 / D50 ratio is 3.0 or less. [2] An additive for a topical skin preparation comprising the paramylon particles according to [1]. [3] A topical skin preparation containing the additive for a topical skin preparation according to [2]. [4] The topical skin preparation according to [3], which is for use in cosmetics or quasi-drugs. [5] A method for producing the paramylon particles according to [1], wherein the HSP value is 25 (MPa １／２ ) A manufacturing method comprising a step of grinding coarse paramylon particles with or without the use of the following solvent. [6] The manufacturing method according to [5], wherein the boiling point of the solvent is 50°C or higher and 120°C or lower. [7] Use of the paramylon particles according to [1] for addition to a topical skin preparation (application). [8] Use of the paramylon particles according to [1] as an additive for a topical skin preparation (application). [9] Use of a composition containing the paramylon particles according to [1] as a topical skin preparation (application).

[0009] According to the present invention, it is possible to provide paramylon particles that are prevented from fusing together and that, when formulated into a skin topical preparation, can reduce stickiness and roughness.

[0010] Figure 1 is an SEM image of paramylon particles A. Figure 2 is an SEM image of paramylon particles B. Figure 3 is an SEM image of paramylon particles C.

[0011] Hereinafter, embodiments of the present invention will be described in detail, but the present invention is not limited to the following embodiments.

[0012] In the paramylon particles according to the embodiment, the 50% cumulative diameter (D50) and the 90% cumulative diameter (D90) in a volume-based cumulative particle size distribution curve are such that the D50 is 1 μm or more and 10 μm or less (sometimes expressed as "1 to 10 μm"; the same applies below), and the D90 / D50 is 3.0 or less.

[0013] Paramylon is a polysaccharide (β-1,3-glucan) produced as an intracellular storage substance unique to Euglena (Euglena gracilis). Within Euglena cells, it exists as paramylon granules, which are aggregates of multiple glucan molecules (three chain-like β-1,3-glucans forming a right-handed triple helix structure) (see, for example, Food Sci Nutr. 2023;11:953-962).

[0014] β-1,3-glucan refers to a polysaccharide structure in which glucose is linked by β1,3 bonds, and paramylon is said to have approximately 2,000 glucose bonds.

[0015] Paramylon particles according to the embodiment are particles made of paramylon extracted from Euglena cells and are distinct from paramylon granules present within Euglena cells. These paramylon particles are aggregates of the above-described glucan molecules, and the β-1,3-glucan that constitutes the glucan molecules may be unbranched or branched chains.

[0016] The paramylon particles according to the embodiment may have any shape, but have specific limitations on their particle size distribution. That is, while the shape of the paramylon particles may be any shape, such as spherical or oblate spheroid (flat spheroid), the particle size distribution of the paramylon particles is quite different from that of naturally occurring particles or particles produced by conventional methods.

[0017] That is, in the cumulative particle size distribution curve based on volume, the 50% cumulative diameter (D50) and the 90% cumulative diameter (D90) are characterized in that D50 is 1 μm or more and 10 μm or less, and D90 / D50 is 3.0 or less. By having such a particle size distribution, when formulated into a skin topical preparation, it becomes possible to reduce stickiness and roughness. Note that D90 / D50 may be 2 or less.

[0018] The 50% cumulative diameter (D50) refers to the particle diameter at the point where the cumulative curve is 50% when the cumulative particle size distribution curve (cumulative curve) is calculated assuming the total volume of the particle population to be 100%, and the 90% cumulative diameter (D90) refers to the particle diameter at the point where the cumulative curve is 90%. The cumulative particle size distribution curve is preferably based on a laser diffraction scattering method.

[0019] The paramylon particles according to the embodiment have a small particle size and a narrow D50 range of 1 μm to 10 μm. Furthermore, because the D90 / D50 ratio is a low value of 3.0 or less, the number of paramylon particles with a particle size larger than the particle size corresponding to D50 is very small.

[0020] When unfused and fused paramylon particles are mixed, the particle size distribution curve (horizontal axis: particle size, vertical axis: frequency) will have a peak at a position corresponding to the particle size of the unfused paramylon particles, as well as a peak at a position corresponding to the particle size of the fused paramylon particles, resulting in a large D90 / D50 value (corresponding to a D90 / D50 value exceeding 3.0). In contrast, the paramylon particles according to the embodiment have a D90 / D50 of 3.0 or less, meaning that they are substantially free of fused large paramylon particles, and the particle size distribution curve will show a single sharp peak at a position corresponding to the particle size of the unfused paramylon particles. Note that because the paramylon particles according to the embodiment have such a size and particle size distribution, they can also be called paramylon microparticles.

[0021] The D50 of the paramylon particles may be 2 μm or more, 3 μm or more, or 3.5 μm or more, or 9 μm or less, 8 μm or less, or 7 μm or less, or 2 to 9 μm, 2 to 8 μm, 2 to 7 μm, 3 to 9 μm, 3 to 8 μm, 3 to 7 μm, 3.5 to 9 μm, 3.5 to 8 μm, or 3.5 to 7 μm.

[0022] The D90 / D50 of the paramylon particles may be 0.2 or more, 0.5 or more, or 1 or more, and may be 2.5 or less, 2.3 or less, 2.1 or less, 2.0 or less, 1.5 or less, 1.4 or less, or 1.3 or less. Alternatively, it may be 0.2 to 3.0, 0.2 to 2.5, 0.2 to 2.3, 0.2 to 2.1, 0.2 to 2.0, 0.2 to 1.5, 0.2 to 1.4, 0.2 to 1.3, 0.5 to 3.0, 0.5 to 2.5, 0.5 to 2.3, 0.5 to 2.1, 0.5 to 2.0, 0.5 to 1.5, 0.5 to 1.4, 0.5 to 1.3, 1 to 3.0, 1 to 2.5, 1 to 2.3, 1 to 2.1, 1 to 2.0, 1 to 1.5, 1 to 1.4, or 1 to 1.3.

[0023] By ensuring that D50 and D90 / D50 are within the above ranges, stickiness and roughness can be further reduced when the paramylon particles are formulated into an external skin preparation.

[0024] The above-mentioned paramylon particles can be added to topical skin preparations. That is, the paramylon particles can be used as an additive for topical skin preparations. Topical skin preparations refer to compositions applied to the skin, and include cosmetics, fragrances, cosmetics, pharmaceuticals, and quasi-drugs. Topical skin preparations are preferably cosmetics or quasi-drugs. Cosmetics include sunscreens. The sunscreen may be an oil-in-water (O / W) sunscreen or a water-in-oil (W / O) sunscreen. When paramylon particles have an oblate spherical shape, the flat shape can be expected to have a light-blocking effect, making them useful as an additive for sunscreens.

[0025] The topical skin preparation contains ingredients that topical skin preparations typically contain, depending on the type of topical skin preparation, and in addition to these ingredients, it also contains paramylon particles.

[0026] Examples of ingredients typically contained in topical skin preparations include aqueous components, oily components, surfactants, moisturizers, thickeners, powder components, preservatives, antioxidants, chelating agents, fragrances, film-forming agents, and solvents.

[0027] Examples of aqueous components include water (distilled water, purified water, hot spring water, deep sea water, etc.), water-soluble solvents, and mixtures thereof.

[0028] Examples of oily components include fats and oils, waxes, hydrocarbon oils, vegetable oils, ester oils, higher alcohols, higher fatty acids, silicone oils, and oil-soluble ultraviolet absorbers. Examples of oil-based components other than oil-soluble UV absorbers include liquid oils and fats such as linseed oil, camellia oil, macadamia nut oil, corn oil, olive oil, avocado oil, camellia oil, castor oil, safflower oil, apricot kernel oil, cinnamon oil, jojoba oil, grape oil, almond oil, rapeseed oil, sesame oil, sunflower oil, wheat germ oil, rice germ oil, rice bran oil, cottonseed oil, soybean oil, peanut oil, tea seed oil, evening primrose oil, egg yolk oil, cod liver oil, triglycerin, glyceryl trioctanoate, and glyceryl triisopalmitate; octanoic acid esters such as cetyl octanoate, isooctanoic acid esters such as glyceryl tri-2-ethylhexanoate and pentaerythritol tetra-2-ethylhexanoate, lauric acid esters such as hexyl laurate, and myristates such as isopropyl myristate and octyldodecyl myristate. acid esters, palmitic acid esters such as octyl palmitate, stearic acid esters such as isocetyl stearate, isostearic acid esters such as isopropyl isostearate, isopalmitic acid esters such as octyl isopalmitate, oleic acid esters such as isodecyl oleate, adipic acid diesters such as diisopropyl adipate, sebacate diesters such as diethyl sebacate, ester oils such as diisostearyl malate and macadamia nut fatty acid phytosteryl; hydrocarbon oils such as liquid paraffin, isododecane, and squalane; silicone oils such as methylpolysiloxane (e.g., dimethicone), methylphenylpolysiloxane, methylhydrogenpolysiloxane, and methylcyclopolysiloxane (e.g., cyclopentasiloxane).The oil-soluble UV absorber is not particularly limited, but specific examples include organic UV absorbers such as ethylhexyl methoxycinnamate, octocrylene, dimethicodiethyl benzalmalonate, polysilicon-15, t-butyl methoxydibenzoylmethane, ethylhexyl triazone, diethylamino hydroxybenzoyl hexyl benzoate, bisethylhexyloxyphenol methoxyphenyl triazine, oxybenzone-3, methylene bisbenzotriazolyl tetramethylbutylphenol, phenylbenzimidazole sulfonic acid, homosalate, and ethylhexyl salicylate. The oil component can be used alone or in combination of two or more.

[0029] Examples of surfactants include anionic surfactants, cationic surfactants, amphoteric surfactants, nonionic surfactants, and silicone surfactants. Surfactants can be used singly or in combination of two or more. Examples of nonionic surfactants include polyglyceryl-5 stearate and polyglyceryl stearate. Examples of silicone surfactants include polyoxyalkylene-modified silicone, polyoxyalkylene / alkyl-co-modified silicone, polyglycerin-modified silicone, and polyglycerin / alkyl-co-modified silicone. Specific examples of silicone surfactants include PEG-9 polydimethylsiloxyethyl dimethicone and PEG-10 dimethicone.

[0030] Examples of moisturizing agents include saturated monohydric alcohols having from 1 to 3 carbon atoms, such as ethanol and isopropyl alcohol, polyhydric alcohols, such as 1,3-butylene glycol, dipropylene glycol, glycerin, 1,2-pentanediol, 1,2-propanediol, 1,3-propanediol, isoprene glycol, polyglycerin, sorbitol, and mannitol, and sodium hyaluronate. These moisturizing agents can be used alone or in combination of two or more.

[0031] Examples of thickeners that can be used include polysaccharide thickeners, organic clay minerals, acrylic acid amide copolymers, polyacrylic acid-based water-soluble polymers, cellulose-based thickeners, and other thickeners. These thickeners can be used alone or in combination. Examples of polysaccharide thickeners include pectin, guar gum, xanthan gum, carrageenan, gellan gum, gum arabic, and locust bean gum. Examples of clay minerals include magnesium aluminum silicate, magnesium sodium silicate, bentonite, aluminum silicate, and sodium silicate. Examples of organic clay minerals include dimethyl distearammonium hectorite, dimethyl alkyl ammonium hectorite, benzyl dimethyl stearyl ammonium hectorite, and magnesium aluminum silicate treated with distearyl dimethyl ammonium chloride. Examples of acrylic acid amide copolymers include polyacrylamide, (hydroxyethyl acrylate / sodium acryloyldimethyltaurate) copolymer, (sodium acrylate / sodium acryloyldimethyltaurate) copolymer, (ammonium acryloyldimethyltaurate / VP) copolymer, (ammonium acryloyldimethyltaurate / beheneth-25 methacrylate) crosspolymer, polyacrylate crosspolymer-11, and sodium polyacryloyldimethyltaurate. Examples of polyacrylic acid-based water-soluble polymers include acrylic acid-based polymers such as polyacrylic acid, carboxyvinyl polymer, alkyl-modified carboxyvinyl polymer, polyacrylic acid amide, and acrylamide / acrylic acid copolymer. These acrylic acid-based polymers are typically neutralized with sodium hydroxide, potassium hydroxide, triethanolamine, triethylamine, basic amino acids such as lysine and arginine, or the like. Examples of cellulose-based thickeners include methylcellulose, ethylcellulose, carboxymethylcellulose, cellulose gum (sodium carboxymethylcellulose), hydroxyethyl cellulose, hydroxypropyl cellulose, hydroxypropylmethylcellulose, crystalline cellulose, and cellulose nanofiber. Other thickeners include chitin nanofiber, paramylon nanofiber, sodium chloride (Na chloride), etc.

[0032] The powder component may be a known powder used in cosmetics, such as an extender powder or a color pigment. The powder component may be used alone or in combination of two or more. Examples of the powder component include ultraviolet scattering agents such as fine particle titanium oxide and fine particle zinc oxide. While both untreated and hydrophobically treated ultraviolet scattering agents can be used as the ultraviolet scattering agent, ultraviolet scattering agents that have been hydrophobically treated with a surface treatment agent are preferred. Examples of surface treatment agents that can be used include those commonly used in the cosmetic field, such as dimethicone, silicones such as alkyl-modified silicone, alkoxysilanes such as octyltriethoxysilane, dextrin fatty acid esters such as dextrin palmitate, fatty acids such as stearic acid, metal soaps such as aluminum stearate, and amino acids such as N-acylglutamic acid.

[0033] Examples of color pigments, which are powder components, include red iron oxide, yellow iron oxide, black iron oxide, cobalt oxide, chromium oxide, ultramarine, Prussian blue, titanium oxide, zinc oxide, pearl pigments, organic pigments, natural dyes (carmine, safflower, etc.), etc. The color pigments can be used alone or in combination of two or more.

[0034] As the preservative, known preservatives used in cosmetics such as caprylyl glycol and phenoxyethanol can be used. The preservatives can be used alone or in combination of two or more. Examples of the preservative include phenoxyethanol.

[0035] As the chelating agent, known chelating agents used in cosmetics such as disodium salt of ethylenediaminetetraacetic acid (EDTA-2Na) can be used. The chelating agents can be used alone or in combination of two or more.

[0036] Examples of the solvent include 1,2-hexanediol, 1,2-pentanediol, 1,3-butylene glycol, 2-octyldodecanol, PEG-6, PEG-8, and diethylhexyl sebacate.

[0037] As the film-forming agent, a known film-forming agent used in cosmetics, such as a mixture of trimethylsiloxysilicate and dimethicone, can be used. The film-forming agents can be used alone or in combination of two or more.

[0038] In addition to the above-mentioned ingredients, the topical skin preparation may contain, as needed, ingredients commonly used in quasi-drugs and cosmetics, such as whitening agents, alcohols, powdered ingredients, aqueous surfactants, etc. The topical skin preparation can be produced by a conventional method.

[0039] Application to the skin can be carried out by methods commonly used for quasi-drugs or cosmetics, such as applying or spraying the product as a liquid onto the skin, or contacting the product with the skin in a state where it is impregnated into a nonwoven fabric or the like.

[0040] The quasi-drugs may be in the form of liquid, cream, spray, etc., and the cosmetics may be in the form of lotion, serum, cream, emulsion, etc.

[0041] Paramylon particles have an HSP value of 25 (MPa １／２ ) can be produced by a method including a step of grinding coarse paramylon particles with or without the use of the following solvents. Coarse paramylon particles can be obtained from Euglena by separation, isolation, or purification according to conventional methods. Paramylon particles refer to particles having (1) a D50 of 1 μm or more and 10 μm or less, and (2) a D90 / D50 ratio of 3.0 or less, while coarse paramylon particles refer to particles having (3) a D50 of more than 10 μm and / or (4) a D90 / D50 ratio of more than 3.0. Coarse paramylon particles typically have a D50 of about 2 to 5 μm and a D90 / D50 ratio of about 9.

[0042] Paramylon particles can be produced by pulverizing the coarse paramylon particles so that the particle size distribution falls within the desired range. １／２) By producing paramylon particles using a method that includes a step of pulverizing coarse paramylon particles with the following solvent, fusion of paramylon particles can be prevented and production efficiency can be improved. Furthermore, by producing paramylon particles using a method that includes a step of pulverizing coarse paramylon particles without using the solvent, the step of removing the solvent is unnecessary, thereby improving production efficiency.

[0043] The pulverization method may be a ball mill, a bead mill, a jet mill, or the like, and may be either a wet pulverization or a dry pulverization.

[0044] When pulverizing using a ball mill or bead mill, beads and coarse paramylon particles can be placed in a pulverizing container, sealed, and pulverized. Known materials such as alumina, zirconia, stainless steel, and glass can be used as the material for the beads. Bead diameters of, for example, 5 mm, 2 mm, 1 mm, and 0.5 mm can be used. The HSP value is 25 (MPa １／２ When grinding with a solvent of the following formula, a grinding vessel is used, and 100 g of glass beads (diameter: 5 mm, for example) is mixed with 1 to 10 g of coarse paramylon particles and a solution with an HSP value of 25 (MPa). １／２ ) 10 to 30 g of the following solvent is added and sealed, and the coarse paramylon particles can be pulverized using a ball mill (rotor mixer). The pulverization time can be determined appropriately depending on the type and amount of beads and the rotation speed, but is usually 10 minutes to 20 hours.

[0045] The HSP value is the Hansen Solubility Parameter, which is a value used to predict the solubility of a substance (Polymer Handbook 4th edition, John Wiley & Sons, Inc., VII / 698-VII / 701, 1999).

[0046] HSP value is 25 (MPa １／２ ) or less solvent, 1-propanol (HSP value: 24.6 (MPa １／２ )), 2-propanol (HSP value: 23.5 (MPa １／２ )), ethyl acetate (HSP value: 18.2 (MPa１／２ )), cyclohexane (HSP value: 16.8 (MPa １／２ )), n-hexane (HSP value: 14.9 (MPa １／２ )) and the like. The HSP value of the solvent is 20 (MPa １／２ ) or less, or 18 (MPa １／２ ) or less, fusion of paramylon particles can be more effectively prevented. １／２ )

[0047] After grinding, the HSP value was 25 (MPa １／２ ) It is preferable to remove at least a portion of the solvent and the beads described below. Methods for removing at least a portion of the solvent include methods such as drying by heating. The boiling point of the solvent may be 50°C or higher and 120°C or lower, 60°C or higher and 110°C or lower, or 70°C or higher and 100°C or lower. By ensuring that the boiling point of the solvent is within the above range, the solvent can be efficiently removed during the production of paramylon particles, improving production efficiency.

[0048] When pulverizing using a jet mill, the raw materials may be pulverized by colliding with each other, or by colliding with a collision plate. The pulverizer used may also be a pulverizer-classifier that also has a classification function. A pulverization method using a pulverizer-classifier that has both pulverization and classification functions can obtain the desired product in a single process.

[0049] Paramylon particles may be produced by a method including a step of crushing coarse paramylon particles and then classifying the resulting paramylon particles. Methods for classifying paramylon particles include sieving and wind (airflow) classification.

[0050] The paramylon coarse particles used in producing paramylon particles may be surface-treated for the purpose of hydrophobization. Paramylon particles with hydrophobized surfaces can be obtained by producing paramylon particles using surface-treated paramylon coarse particles. Paramylon particles with hydrophobized surfaces may also be prepared by subjecting non-surface-treated paramylon particles to surface treatment. By hydrophobizing the surfaces of paramylon particles, improved usability (non-stickiness) is expected when used as an additive for topical skin preparations.

[0051] Surface treatments include polysiloxane treatment, alkylsilane treatment, alkyltitanate treatment, and acrylic silicone copolymer treatment, and can be selected according to the oil used. Compounds used in polysiloxane treatment include methicone and hydrogen dimethicone. Compounds used in alkylsilane treatment include triethoxycaprylylsilane. Compounds used in alkyltitanate treatment include isopropyl stearoyl titanate.

[0052] As a surface treatment method for the paramylon coarse particles, the HSP value is 25 (MPa １／２ ) Paramylon particles can be obtained by mixing coarse paramylon particles with a solution prepared by dissolving a compound used for surface treatment in the following solvent, pulverizing the coarse paramylon particles so that the particle size distribution falls within the desired range, and then removing the solvent. Alternatively, paramylon particles can be produced by a method that includes a step of mixing and pulverizing the compound used for surface treatment with coarse paramylon particles without using the solvent, thereby eliminating the need for a step of removing the solvent and improving production efficiency.

[0053] On the other hand, when using a water-soluble compound such as an organic acid, the organic acid (salt) dissolved in water is mixed with the paramylon coarse particles, and then a flocculant is added to obtain paramylon coarse particles that have been surface-treated with an organic acid salt. The surface-treated paramylon coarse particles have an HSP value of 25 (MPa １／２ ) Paramylon particles can be obtained by a method including a step of grinding with the following solvents. Examples of organic acids (salts) include stearic acid (salts) and myristic acid (salts), and examples of flocculants include polyvalent metal salts such as calcium chloride, magnesium chloride, and aluminum salts. The term "acid (salt)" means "acid or its salt."

[0054] The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples.

[0055] [Preparation of Paramylon Particles] (Paramylon Particles A) 5.0 g of coarse paramylon particles (manufactured by Eugleed Co., Ltd.), 90 g of glass beads (diameter: 5 mm), and 25 g of cyclohexane were placed in a 100 mL sample tube and sealed. The sample tube was placed on a rotor mixer (manufactured by AS ONE Corporation, model number: VMR-5R) rotating at 60 rpm, and pulverized for 10 hours. After pulverization, the glass beads were removed from the liquid in the sample tube using a sieve, and the paramylon particles were filtered out and further dried with hot air at 80°C for 4 hours to obtain paramylon particles A.

[0056] The coarse paramylon particles used in the examples were obtained from a resistant strain of Euglena (Euglena gracilis Z strain NIES48). The resistant strain has acquired tolerance to a culture medium with a high glucose concentration through the acclimation step. Therefore, even if Euglena is cultured in a culture medium with a high glucose concentration of more than 2% and not more than 8% during the growth step, the growth rate is not reduced or inhibited, and Euglena can be grown stably and efficiently. This allows for stable and efficient production of paramylon.

[0057] (Paramylon Particles B) Paramylon particles B were obtained in the same manner as paramylon particles A, except that 25 g of ion-exchanged water was used instead of cyclohexane.

[0058] (Paramylon Particles C) The untreated coarse paramylon particles used in the preparation of paramylon particles A were prepared as paramylon particles C.

[0059] (Paramylon Particles D) Paramylon coarse particles (manufactured by Eugleed Co., Ltd.) were finely pulverized using a supersonic jet pulverizer LJ-3 (manufactured by Nippon Pneumatic Mfg. Co., Ltd.) at a pulverization pressure of 0.6 MPa.

[0060] (Paramylon Particles E Surface-Treated with Calcium Stearate) 40 g of water, 0.3 g of stearic acid, and 0.42 g of 10% sodium hydroxide aqueous solution were charged into a 100 mL reactor and heated to 80°C with stirring until dissolved. 10.0 g of paramylon coarse particles (manufactured by Eugleed Co., Ltd.) was then added. Next, 5.9 g of 1% calcium chloride aqueous solution was gradually added dropwise while stirring vigorously. After the addition, stirring was continued for 10 minutes. Water was added to the resulting mixture, which was then centrifuged. The precipitated particles were then collected and dried. The resulting powder was solidified, so it was pulverized. The resulting powder, 10 g of 5 mm diameter glass beads, and 15 g of cyclohexane were placed in a 50 mL sample tube and vigorously shaken for 30 minutes using a paint shaker. The mixture was then filtered and dried to obtain paramylon particles E surface-treated with calcium stearate.

[0061] (Paramylon particles F surface-treated with methicone) 8 g of normal pentane, 0.15 g of methicone (KF-99-P, manufactured by Shin-Etsu Chemical Co., Ltd.), and 8.0 g of coarse paramylon particles (manufactured by Eugleed Co., Ltd.) were added to a 100 mL reactor. After reacting at 60°C for 1 hour with stirring, the temperature was gradually increased while distilling off the normal pentane, and the mixture was maintained at 120°C for 6 hours. The resulting powder was pulverized in the same manner as paramylon particles E, to obtain paramylon particles F surface-treated with methicone.

[0062] (Paramylon particles G surface-treated with hydrogen dimethicone) 8 g of normal pentane, 0.15 g of hydrogen dimethicone (KF-9901, manufactured by Shin-Etsu Chemical Co., Ltd.), and 8.0 g of coarse paramylon particles (manufactured by Eugleed Co., Ltd.) were added to a 100 mL reactor. After reacting at 60°C for 1 hour with stirring, the temperature was gradually increased while distilling off the pentane, and the mixture was maintained at 120°C for 6 hours. The resulting powder was designated paramylon particles G surface-treated with hydrogen dimethicone.

[0063] (Paramylon Particles H Surface-Treated with Hydrogen Dimethicone) Paramylon Particles G were pulverized in the same manner as paramylon Particles E to obtain paramylon Particles H surface-treated with hydrogen dimethicone.

[0064] (Paramylon Particles I Surface-Treated with Triethoxycaprylylsilane) 7 g of isopropanol, 0.18 g of triethoxycaprylylsilane (AES-3083, manufactured by Shin-Etsu Chemical Co., Ltd.), 0.3 g of water, 1.0 g of 28% aqueous ammonia, and 6.0 g of coarse paramylon particles (manufactured by Eugleed Co., Ltd.) were added to a 100 mL reactor and reacted at 80°C for 4 hours with stirring. Water was added to the resulting mixture, which was then centrifuged. The precipitated particles were then collected and dried. The resulting powder was pulverized in the same manner as for paramylon particles E to obtain paramylon particles I surface-treated with triethoxycaprylylsilane.

[0065] Paramylon particles A to C were subjected to SEM observation using an electron microscope (manufactured by JEOL Ltd., model number: JCM-6000). The results are shown in Figures 1 to 3. Figure 1 is an SEM image of paramylon particle A, Figure 2 is an SEM image of paramylon particle B, and Figure 3 is an SEM image of paramylon particle C.

[0066] The particle size and particle size distribution of paramylon particles A to I were measured under the following measurement conditions. The results are shown in Tables 1 and 2. Note that paramylon particle B aggregated into thin plates and did not easily break down into powder, so its particle size could not be measured. The measurement conditions were as follows: Measurement device: Particle size distribution measurement device (manufactured by Spectris Inc., Malvern Panalytical Division, model: Mastersizer 3000, dry type) Dry laser diffraction scattering method Dispersion pressure: 2.0 bar Venturi: HE venturi Particle refractive index: 1.468 Particle absorption number: 0.01 Particle density: 1.0 g / cm ３ Particle shape: non-spherical Solvent: air Measurement range: 0.1 μm to 3500 μm

[0067] (Measurement of static friction coefficient) The static friction coefficient of paramylon particles A to D was measured under the following measurement conditions. The results are shown in Table 1. Note that paramylon particle B was in the form of a thin plate-like mass, so it was impossible to measure the static friction coefficient. The measurement conditions were as follows: Measuring device: (Trinity Lab Co., Ltd., multi-function static and dynamic friction measuring device, model: TL201Ts) Speed: 10 mm / sec Vertical load: 50 g Movement range: 10 mm

[0068]

[0069]

[0070] [Preparation of Oil-in-Water (O / W) Sunscreen] The following materials were prepared. Purified water, Polyglyceryl-5 stearate and polyglyceryl stearate mixture (Taiyo Chemical Co., Ltd., product name: Sunsoft Alpha-C), 1,3-butylene glycol (Daicel Corporation, product name: 1,3-butylene glycol (UK)), Glycerin (Sakamoto Pharmaceutical Co., Ltd., product name: Cosmetic concentrated glycerin), Diethylhexyl sebacate (Nippon Fine Chemical Co., Ltd., product name: FineNeo-EHS), Dimethicone (Shin-Etsu Chemical Co., Ltd., product name: KF-96A-6cs), Macadamia nut fatty acid phytosteryl (Nippon Fine Chemical Co., Ltd., product name: Plandeool-MAS), Squalane (Nikko Chemicals Co., Ltd., product name: Sugar Squalane), Ammonium acryloyldimethyltaurate / VP copolymer (Clariant, product name: ARISTOFLEX AVC). Phenoxyethanol (manufactured by Yokkaichi Chemical Co., Ltd., product name: Phenoxyethanol-S) Sodium hyaluronate (manufactured by Kewpie Corporation, product name: Hyaluronic acid HA-LQ) Aqueous dispersion of titanium oxide microparticles (manufactured by Sakai Chemical Industry Co., Ltd., product name: DIS-AB-10W, average particle size of titanium oxide: 15 nm, powder concentration: 50%) Aqueous dispersion of zinc oxide microparticles (manufactured by Sakai Chemical Industry Co., Ltd., product name: DIF-AB-33W, average particle size of zinc oxide: 35 nm, powder concentration: 60%) Methyl methacrylate crosspolymer (manufactured by Matsumoto Yushi Pharmaceutical Co., Ltd., product name: Matsumoto Microsphere M-305, average particle size 8 μm)

[0071] The O / W sunscreens of Examples 1 and 2 and Comparative Examples 1 to 3 were prepared according to the following procedure. The amounts (parts by mass) of the components in each sunscreen are shown in Table 3. The amount of purified water in Table 3 indicates the total amount of purified water used in preparing each O / W sunscreen.

[0072] Example 1 First, 28.00 parts by mass of purified water, 2.50 parts by mass of a mixture of polyglyceryl-5 stearate and polyglyceryl stearate, 1.00 parts by mass of 1,3-butylene glycol, and 2.00 parts by mass of glycerin were mixed at 80°C to obtain Mixture 1. Furthermore, 6.00 parts by mass of diethylhexyl sebacate, 1.00 parts by mass of dimethicone, 0.20 parts by mass of phytosteryl macadamiate, and 4.00 parts by mass of squalane were mixed at 80°C to obtain Mixture 2.

[0073] Next, Mixture 2 was added to Mixture 1 and emulsified to obtain an emulsion. A mixture of 14.70 parts by mass of purified water and 0.30 parts by mass of (ammonium acryloyldimethyltaurate / VP) copolymer was added to the obtained emulsion and mixed, and then cooled to 40°C to obtain Mixture 3.

[0074] Next, a mixture of 1.99 parts by mass of purified water and 0.01 parts by mass of sodium hyaluronate and 0.30 parts by mass of phenoxyethanol were added to and mixed with Mixture 3 to obtain Mixture 4.

[0075] Finally, a mixture of 5.00 parts by mass of 1,3-butylene glycol and 5.00 parts by mass of paramylon particles A, 8.00 parts by mass of an aqueous dispersion of titanium oxide microparticles, and 20.00 parts by mass of an aqueous dispersion of zinc oxide microparticles were added to mixture 4 and mixed to prepare a sunscreen.

[0076] Example 2 A sunscreen was prepared in the same manner as in Example 1, except that 5.00 parts by mass of paramylon particles D were used instead of 5.00 parts by mass of paramylon particles A.

[0077] Comparative Example 1 A sunscreen was prepared in the same manner as in Example 1, except that 5.00 parts by mass of purified water was used in place of 5.00 parts by mass of paramylon particles A.

[0078] Comparative Example 2 A sunscreen was prepared in the same manner as in Example 1, except that 5.00 parts by mass of paramylon particles C were used instead of 5.00 parts by mass of paramylon particles A.

[0079] Comparative Example 3 A sunscreen was prepared in the same manner as in Example 1, except that 5.00 parts by mass of methyl methacrylate crosspolymer was used instead of 5.00 parts by mass of paramylon particles A.

[0080]

[0081] [Evaluation test of O / W sunscreens] (Feeling of use (stickiness)) Each sunscreen prepared in Examples 1 and 2 and Comparative Examples 1 to 3 was applied to the skin of 10 expert panels, and the expert panels evaluated the degree of stickiness according to the following evaluation criteria. The results are shown in Table 4. <Evaluation criteria> A: Very good (very excellent lack of stickiness), 9 or more panels rated as good B: Good (excellent lack of stickiness), 3 to 8 panels rated as good C: Poor (sticky), 2 or fewer panels rated as good

[0082] (Feeling when used (roughness)) Each of the sunscreens prepared in Examples 1 and 2 and Comparative Examples 1 to 3 was applied to the skin of 10 expert panels, and the expert panels evaluated the degree of roughness according to the following evaluation criteria. The results are shown in Table 4. <Evaluation criteria> A: Very good (very excellent in terms of lack of roughness), 9 or more panels rated it as good B: Good (excellent in terms of lack of roughness), 3 to 8 panels rated it as good C: Poor (roughness present), 2 or fewer panels rated it as good

[0083] (Storage Stability) Each sunscreen prepared in Examples 1 and 2 and Comparative Examples 1 to 3 was filled into a glass vial and stored in an incubator. Accelerated testing was performed under the following conditions: 5°C for 3 months, 25°C for 3 months, 40°C for 3 months, and 50°C for 1 month. The condition of the sunscreen after the accelerated testing was observed, and changes in appearance and viscosity were evaluated according to the following evaluation criteria. The results are shown in Table 4. <Evaluation Criteria> A: Very good (little change in condition compared to before the test) B: Good (slight change in condition compared to before the test) C: Poor (significant change in condition compared to before the test)

[0084] (UV Protection Performance) Each of the sunscreens prepared in Examples 1 and 2 and Comparative Examples 1 to 3 was applied to a PMMA plate (manufactured by Helio Screen, product name: SB6) at a concentration of 1.3 mg / cm ２ The coating was uniformly applied to a thickness of 100 μm, and then allowed to dry naturally for 15 minutes under light-shielded conditions to form a coating film, thereby preparing a measurement sample. The absorption spectrum (measurement wavelength: 290 to 450 nm) of the prepared measurement sample was measured using an SPF analyzer (manufactured by Labsphere, model: UV-2000S), and the in vitro SPF value and UVAPF value were calculated from the absorption spectrum value. The absorption spectrum was measured at nine points for each measurement sample, and the in vitro SPF value and in vitro UVAPF value were calculated from the respective absorption spectrum values, and the average values ​​of the in vitro SPF values ​​and UVAPF values ​​at the nine points were calculated. Three measurement samples were prepared and measured for each of the sunscreens prepared in Examples 1 and 2 and Comparative Examples 1 to 3, and the average values ​​were used as the in vitro SPF value and in vitro UVAPF value of the measurement sample. The results are shown in Table 4.

[0085] (pH Measurement) Using a pH meter (Model: F-72, manufactured by Horiba, Ltd.), the pH of each of the sunscreen agents prepared in Examples 1 and 2 and Comparative Examples 1 to 3 was measured at 25° C. The results are shown in Table 4.

[0086] (Viscosity Measurement) The viscosity (mPa s) of each sunscreen agent prepared in Examples 1 and 2 and Comparative Examples 1 to 3 was measured using a Brookfield viscometer (manufactured by Toki Sangyo Co., Ltd., model BMII) under the conditions of rotor No. 4, rotation speed: 6 rpm, measurement time: 60 seconds, and temperature: 25° C. The results are shown in Table 4.

[0087]

[0088] [Preparation of Water-in-Oil (W / O) Sunscreen] The following materials were prepared. PEG-9 polydimethylsiloxyethyl dimethicone (Shin-Etsu Chemical Co., Ltd., product name: Silicone KF-6028) PEG-10 dimethicone (Shin-Etsu Chemical Co., Ltd., product name: Silicone KF-6017P) Mixture of trimethylsiloxysilicate and dimethicone (Shin-Etsu Chemical Co., Ltd., product name: Silicone KF-7312K) Isododecane (Nihon Koken Kogyo Co., Ltd., product name: Permethyl 99A) Octyldodecyl myristate (Kyukyu Alcohol Kogyo Co., Ltd., product name: ODM) Dimethicone (Shin-Etsu Chemical Co., Ltd., product name: Silicone KF96A-6cs) Cyclopentasiloxane (Shin-Etsu Chemical Co., Ltd., product name: Silicone KF995) Methyl methacrylate crosspolymer (Matsumoto Oil & Fat Industries Co., Ltd., product name: Matsumoto Microsphere M-305, average particle size 8 μm) Glycerin (manufactured by Miyoshi Oil & Fats Co., Ltd., product name: concentrated glycerin for cosmetics) 1,3-butylene glycol (manufactured by Daicel Corporation, product name: 1,3-butylene glycol (UK)) Sodium chloride (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., product name: sodium chloride) Disodium salt of ethylenediaminetetraacetic acid (EDTA-2Na) (manufactured by Chubu Cherest Co., Ltd., product name: Cherest 2B-SD) Phenoxyethanol (manufactured by Yokkaichi Chemical Industry Co., Ltd., product name: Phenoxyethanol-S) Silicone dispersion of zinc oxide microparticles (manufactured by Sakai Chemical Industry Co., Ltd., product name: DIF-AW4, average particle size of titanium oxide: 20 nm, powder concentration 50%) Silicone dispersion of titanium oxide microparticles (manufactured by Sakai Chemical Industry Co., Ltd., product name: DIS-11A, average particle size of titanium oxide: 15 nm, powder concentration 40%)

[0089] The W / O sunscreen agents of Examples 3 to 6 and Comparative Examples 4 to 6 were prepared according to the following procedure. The amounts (parts by mass) of the components in each sunscreen agent are shown in Tables 5 and 6. The amount of purified water in Tables 5 and 6 indicates the total amount of purified water used in preparing each W / O sunscreen agent.

[0090] Example 3 First, 1.50 parts by weight of PEG-9 polydimethylsiloxyethyl dimethicone, 1.50 parts by weight of PEG-10 dimethicone, 1.00 parts by weight of a mixture of trimethylsiloxysilicate and dimethicone, 9.00 parts by weight of isododecane, 6.00 parts by weight of octyldodecyl myristate, 1.00 parts by weight of dimethicone, and 5.00 parts by weight of paramylon particles E were mixed at room temperature to obtain Mixture 5. Furthermore, 19.15% by weight of purified water, 2.00 parts by weight of glycerin, 3.00 parts by weight of 1,3-butylene glycol, 0.50 parts by weight of Na chloride, 0.05 parts by weight of EDTA-2Na, and 0.30 parts by weight of phenoxyethanol were dissolved and uniformly mixed at 80 ° C., and then cooled to 25 ° C. to obtain Mixture 6.

[0091] Next, Mixture 6 was added to Mixture 5 and emulsified to obtain an emulsion. 30.00 parts by mass of a silicone dispersion of zinc oxide microparticles and 20.00 parts by mass of a silicone dispersion of zinc oxide microparticles were added to the obtained emulsion and mixed to prepare a W / O type sunscreen.

[0092] Example 4 A sunscreen was prepared in the same manner as in Example 3, except that 5.00 parts by mass of paramylon particles F were used instead of 5.00 parts by mass of paramylon particles E.

[0093] Example 5 A sunscreen was prepared in the same manner as in Example 3, except that 5.00 parts by mass of paramylon particles H were used instead of 5.00 parts by mass of paramylon particles E.

[0094] Example 6 A sunscreen was prepared in the same manner as in Example 3, except that 5.00 parts by mass of paramylon particles I were used instead of 5.00 parts by mass of paramylon particles E.

[0095] Comparative Example 4 A sunscreen was prepared in the same manner as in Example 3, except that 5.00 parts by mass of cyclopentasiloxane was used instead of 5.00 parts by mass of paramylon particles E.

[0096] Comparative Example 5 A sunscreen was prepared in the same manner as in Example 3, except that 5.00 parts by mass of paramylon particles G were used instead of 5.00 parts by mass of paramylon particles E.

[0097] Comparative Example 6 A sunscreen was prepared in the same manner as in Example 3, except that 5.00 parts by mass of methyl methacrylate crosspolymer was used instead of 5.00 parts by mass of paramylon particles E.

[0098]

[0099]

[0100] [Evaluation test of W / O type sunscreen agents] (Feeling of use (stickiness)) Each sunscreen agent prepared in Examples 3 to 6 and Comparative Examples 4 to 6 was applied to the skin of 10 expert panels, and the expert panels evaluated the degree of stickiness according to the following evaluation criteria. The results are shown in Table 7. <Evaluation criteria> A: Very good (very excellent lack of stickiness), 9 or more panels rated as good B: Good (excellent lack of stickiness), 4 to 8 panels rated as good C: Fairly good (not sticky), 1 to 3 panels rated as good D: Poor (sticky), 0 panels rated as good

[0101] (Feeling when used (roughness)) Each of the sunscreens prepared in Examples 3 to 6 and Comparative Examples 4 to 6 was applied to the skin of 10 expert panels, and the expert panels evaluated the degree of roughness according to the following evaluation criteria. The results are shown in Table 7. <Evaluation criteria> A: Very good (very excellent lack of roughness), 9 or more panels evaluated as good B: Good (excellent lack of roughness), 4 to 8 panels evaluated as good C: Fairly good (no roughness), 1 to 3 panels evaluated as good D: Poor (sticky), 0 panels evaluated as good

[0102] (Storage Stability) Each sunscreen prepared in Examples 3 to 6 and Comparative Examples 4 to 6 was filled into a glass vial and stored in an incubator. Accelerated testing was performed under the following conditions: 5°C for 1 month, 25°C for 1 month, 40°C for 1 month, and 50°C for 1 month. The condition of the sunscreen after the accelerated testing was observed, and changes in appearance and viscosity were evaluated according to the following evaluation criteria. The results are shown in Table 7. <Evaluation Criteria> A: Very good (little change in condition compared to before the test) B: Good (slight change in condition compared to before the test) C: Poor (significant change in condition compared to before the test)

[0103] (UV Protection Performance) Each sunscreen prepared in Examples 3 to 6 and Comparative Examples 4 to 6 was applied to a PMMA plate (manufactured by Helio Screen, product name: HD6) at a concentration of 1.3 mg / cm ２ The sunscreen was applied uniformly to a thickness of 100 μm and then allowed to dry naturally for 15 minutes under light-shielded conditions to form a coating film, thereby preparing a measurement sample. The in vitro SPF and in vitro UVAPF values ​​of the prepared measurement sample were determined in the same manner as for the measurement samples prepared from the sunscreens of Examples 1 and 2 and Comparative Examples 1 to 3. The results are shown in Table 7.

[0104] (Viscosity Measurement) The viscosity (mPa·s) of each of the sunscreens prepared in Examples 3 to 6 and Comparative Examples 4 to 6 was measured in the same manner as for each of the sunscreens prepared in Examples 1 and 2 and Comparative Examples 1 to 3. The results are shown in Table 7.

[0105]

[0106] Below, examples of topical skin preparations using the paramylon powder or hydrophobized paramylon powder of the present invention are described as Formulation Examples 1 and 2. The topical skin preparations of these Formulation Examples also had reduced stickiness and roughness upon application, providing a good feel when used.

[0107] Formulation Example 1: Calming Lotion Propanediol 12.00% by mass Glycerin 5.00% by mass Bentonite 0.25% by mass Pentylene glycol 1.50% by mass Ethanol 5.00% by mass Citric acid 0.005% by mass Sodium citrate 0.002% by mass Paramylon particles D 1.50% by mass Purified water Balance Total 100.0% by mass

[0108] Formulation Example 2: Skin Care Cream Propanediol 12.00% by mass Glycerin 5.00% by mass Hydroxyethylcellulose 0.05% by mass Polyglyceryl-10 stearate 1.20% by mass Glyceryl stearate 1.50% by mass Behenyl alcohol 4.00% by mass Octyldodecyl myristate 1.00% by mass Squalane 3.00% by mass Pentylene glycol 2.50% by mass Citric acid 0.004% by mass Sodium citrate 0.007% by mass Paramylon particles D 3.00% by mass Purified water Balance Total 100.0% by mass

Claims

1. Paramylon particles, in which, in a volume-based cumulative particle size distribution curve, the 50% cumulative diameter (D50) and the 90% cumulative diameter (D90) are such that the D50 is 1 μm or more and 10 μm or less, and the D90 / D50 is 3.0 or less.

2. An additive for topical skin preparations comprising the paramylon particles described in claim 1.

3. An external preparation for skin, comprising the additive for external preparations for skin described in claim 2.

4. The skin topical preparation according to claim 3, which is for use as a cosmetic or quasi-drug.

5. A method for producing paramylon particles according to claim 1, comprising the steps of: １／２ ) A manufacturing method comprising a step of grinding coarse paramylon particles with or without the use of the following solvent:

6. The manufacturing method according to claim 5, wherein the boiling point of the solvent is 50°C or higher and 120°C or lower.

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