UV protection agent

Abstract

To provide a UV protection agent that can protect against a wide range of wavelengths at low doses, and a topical skin preparation containing the same.SOLUTION: A UV protection agent that contains 2-methylphenyl p-methoxycinnamate (MMPC) particulates with a 50 vol.% particle size (D50) of 50 to 1,000 nm in a cumulative frequency distribution, and a UV absorber capable of absorbing UV-A, and water. There is also provided a topical skin preparation containing the UV protection agent.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to an ultraviolet protection agent, and more particularly to an ultraviolet protection agent containing highly dispersible 2-methylphenyl paramethoxycinnamate microparticles, an ultraviolet absorber having ultraviolet A absorption ability, and water, as well as an external skin preparation containing said ultraviolet protection agent. [Background technology]

[0002] As awareness of the harmful effects of ultraviolet rays on the skin has spread, the demand for ultraviolet protection agents has increased in the cosmetics field and other fields, and products containing ultraviolet protection agents are being used in a variety of product forms. Ultraviolet rays are classified according to their wavelength into long-wavelength UVA (320-400 nm), medium-wavelength UVB (280-320 nm), and short-wavelength UVC (100-280 nm). UVA and UVB rays reach the earth's surface without being absorbed much by the ozone layer, and are the ones that can affect humans, so measures must be taken to deal with them. UV protection agents are broadly divided into UV absorbers and UV scattering agents. For the former type of UV absorbers, UVB absorbers have mainly been used to efficiently suppress UVB, which causes instant sunburn. In recent years, with the growing awareness of preventing photoaging, attention has been focused on protection against UVA, which penetrates deeper into the dermis of the skin and causes spots, wrinkles, and skin cancer due to DNA damage, and there is a growing demand for UVA absorbers. For example, 2-methylphenyl paramethoxycinnamate has been proposed, which has ultraviolet light absorption mainly in the UVB region and also in the UVA region (Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 4229979 Summary of the Invention [Problem to be solved by the invention]

[0004] As described above, in skin topical preparations such as sunscreens, there is a demand for UV protection agents that can protect not only against short-wavelength UVB but also against longer-wavelength UVA, and the search for compounds that have both UVA and UVB absorption capabilities, the combined use of compounds with UVA absorption capabilities and compounds with UVB absorption capabilities, and the combined use of these compounds (UV absorbers) and UV scattering agents are being considered. Until now, in order to obtain the desired UV protection capabilities that meet the standards for cosmetics related to UV protection in the wide UV wavelength range of UVA and UVB, it was necessary to incorporate UV protection agents in high concentrations. This resulted in problems such as increased skin irritation and white cast of the incorporated ingredients, and there is a demand for UV protection agents that can protect against UV rays in smaller amounts.

[0005] An object of the present invention is to provide an ultraviolet protection agent capable of providing protection over a wide wavelength range with a small amount of the agent, and an external skin preparation containing the same. [Means for solving the problem]

[0006] As a result of intensive research by the present inventors to solve the above problems, they have found that by combining 2-methylphenyl paramethoxycinnamate (MMPC), which has an absorption range in the UVB region, with an ultraviolet absorber having ultraviolet A wave absorption ability, it is possible to achieve high ultraviolet protection ability over a wide ultraviolet wavelength range, even when the amount of MMPC used is the same as that of an existing UVB absorber, and in particular, by microparticulating MMPC to an average particle size of less than 1 μm and using it in a form that contains water, it is possible to provide an external skin preparation that has the above-mentioned ultraviolet protection ability and is also rich in moisture and has a refreshing feel when used, thereby completing the present invention.

[0007] That is, in a first aspect, the present invention provides a method for determining a particle diameter distribution of 50% by volume (D 50 The present invention relates to an ultraviolet protection agent comprising 2-methylphenyl paramethoxycinnamate (MMPC) fine particles having a wavelength of 50 to 1,000 nm, an ultraviolet absorber having ultraviolet A wave absorbing ability, and water. As a second aspect, the ultraviolet absorbing agent having ultraviolet A absorbing ability is methylene bisbenzotriazolyl tetramethylbutylphenol (MBBT), 4-tert-butyl-4'-methoxydibenzoylmethane (BMDBM), 2-4[4-(diethylamino)-2-hydroxybenzoyl]hexyl benzoate, dihydroxydimethoxybenzophenone disulfonate sodium salt (oxybenzone-9), dimethoxybenzylidene dioxoimidazolidinepropionate 2-ethylhexyl, terephthalide dicamphor sulfonic acid, oxothiazolidine dibenzoate ... the ultraviolet protection agent according to the first aspect being at least one selected from the group consisting of benzophenone, dihydroxybenzophenone (oxybenzone-1), 2,2',4,4'-tetrahydroxybenzophenone (oxybenzone-2), 2-hydroxy-4-methoxybenzophenone (oxybenzone-3), 2,2'-dihydroxy-4,4'-dimethoxybenzophenone (oxybenzone-6), drometrizole trisiloxane, 4-bisethylhexyloxyphenol methoxyphenyl triazine, and trisbiphenyl triazine. As a third aspect, the MMPC microparticles have a 50% volume particle diameter (D 50 ) is 100 to 500 nm. As a fourth aspect, the present invention relates to the ultraviolet protection agent according to any one of the first to third aspects, in which the MMPC fine particles and the ultraviolet absorber having ultraviolet A absorbing ability are contained in a mass ratio of 5:1 to 1:5. As a fifth aspect, the present invention relates to the ultraviolet protection agent according to any one of the first to fourth aspects, further comprising metal oxide fine particles having an average particle size of 1 to 1,000 nm. As a sixth aspect, the present invention relates to the ultraviolet protection agent according to any one of the first to fifth aspects, further comprising a surfactant. According to a seventh aspect, the present invention relates to the ultraviolet protection agent according to any one of the first to sixth aspects, in which the MMPC fine particles are in the form of an aqueous dispersion of MMPC fine particles. According to an eighth aspect, the present invention relates to an external preparation for skin containing the ultraviolet protection agent according to any one of the first to seventh aspects. As a ninth aspect, the present invention relates to the external skin preparation according to the eighth aspect, which is a cosmetic preparation. Effect of the Invention

[0008] The ultraviolet protection agent of the present invention can provide high ultraviolet protection effect over a wide wavelength range even when incorporated in a small amount, compared to the case where existing UVB absorbents are used. Furthermore, the UV protection agent of the present invention comprises 2-methylphenyl paramethoxycinnamate (MMPC) microparticles, an UV absorber capable of absorbing UV-A rays, and water, thereby making it possible to provide an external skin preparation that is less sticky and has an excellent feel when used. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 shows the particle size distribution of MMPC crystals. [Diagram 2] FIG. 2 shows the particle size distribution of the MMPC fine particles after pulverization. [Diagram 3] FIG. 3 shows the UV protection spectrum of an ointment containing 4-tert-butyl-4'-methoxydibenzoylmethane (BMDBM) in combination with MMPC, or an ointment containing BMDBM in combination with 2-ethylhexyl 4-methoxycinnamate (EHMC). DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] [UV protection agent] The ultraviolet protection agent of the present invention contains 2-methylphenyl paramethoxycinnamate (hereinafter also referred to as MMPC) fine particles, an ultraviolet absorber having ultraviolet A absorbing ability, and water. The present invention will be further described below, but it is not limited to the embodiments and specific examples described in this specification, and various changes and modifications are possible within the scope of the technical idea described in the claims.

[0011] 《2-Methylphenyl paramethoxycinnamate (MMPC)》 The ultraviolet protection agent of the present invention contains 2-methylphenyl paramethoxycinnamate (MMPC) fine particles as an ultraviolet absorbing agent. MMPC is a compound represented by the following general formula I, and is a white crystal with a melting point of 93 to 94° C. MMPC has strong absorption ability in the UVA range and has an ultraviolet light suppressing effect with absorption ability extending to the UVB range. [ka]

[0012] The MMPC microparticles according to the present invention have a 50% volume particle diameter (D 50 ) of 50 to 1,000 nm can be used. The 50% volume particle size in the present invention can be a 50% volume diameter value based on the volume measured by dynamic light scattering. Preferably, the particle diameter of the MMPC microparticles (D 50 ) may be between 100 and 500 nm, or may be between 150 and 350 nm. The shape of the MMPC fine particles is not particularly limited, and may be, for example, spherical, polyhedral, angular, hollow, rod-like, plate-like, or irregular.

[0013] The MMP microparticles are obtained by pulverizing MMPC bulk powder into fine particles, which generally have a size of about 10 μm to 500 μm. As a method for reducing raw powder to fine particles by grinding, wet grinding using a media agitator grinder can be used. In this method, a liquid containing the material to be ground is agitated together with grinding media consisting of tiny beads, and the material is ground and dispersed by the shearing force of the media to obtain nano-level fine particles. Media agitator grinders are classified according to the grinding media used and the target particle size, and are known by names such as ball mills, bead mills, sand mills, and basket mills.

[0014] The MMPC microparticles may be used in the form of a dispersion in water. An aqueous dispersion of MMPC microparticles can be obtained by pulverizing MMPC bulk powder by the above-mentioned wet pulverization. In this case, the concentration of MMPC in the aqueous dispersion is not particularly limited, but can be, for example, 1 to 50% by mass, and can be 10 to 30% by mass. If the concentration of MMPC is too high, the viscosity of the aqueous dispersion increases, making it difficult to uniformly disperse MMPC, and if the concentration of MMPC is too low, the concentration of MMPC in the final product, which is an external preparation for skin, decreases. Therefore, the concentration of MMPC may be selected according to the purpose.

[0015] <Ultraviolet absorbing agent> The ultraviolet absorbing agent having ultraviolet A (UVA) absorbing ability contained in the ultraviolet ray protection agent of the present invention is In this case, any ultraviolet absorbing agent (ultraviolet absorbing compound) that can be applied to external preparations for the skin can be used without any restrictions.

[0016] Examples of ultraviolet absorbers having UVA absorbing ability include methylenebisbenzotriazolyltetramethylbutylphenol (MBBT), 4-tert-butyl-4'-methoxydibenzoylmethane (BMDBM), hexyl 2-4[4-(diethylamino)-2-hydroxybenzoyl]benzoate, sodium dihydroxydimethoxybenzophenone disulfonate (oxybenzone-9), 2-ethylhexyl dimethoxybenzylidene dioxoimidazolidinepropionate, terephthalidenedicamphorsulfonic acid, and oxothiazolidine. Examples of ultraviolet absorbers that are believed to absorb both UVA and UVB rays include dihydroxybenzophenone (oxybenzone-1), 2,2',4,4'-tetrahydroxybenzophenone (oxybenzone-2), 2-hydroxy-4-methoxybenzophenone (oxybenzone-3), 2,2'-dihydroxy-4,4'-dimethoxybenzophenone (oxybenzone-6), drometrizole trisiloxane, 4-bisethylhexyloxyphenol methoxyphenyl triazine, and trisbiphenyl triazine. These ultraviolet absorbing agents having UVA absorbing ability may be used alone or in combination of two or more.

[0017] The ultraviolet protection agent of the present invention must contain the above-mentioned ultraviolet absorber having UVA absorption ability, but it may also contain ultraviolet absorbers other than those mentioned above, for example, ultraviolet absorbers having UVB absorption ability, as long as the effects of the present invention are not impaired. Examples of ultraviolet absorbers having UVB absorption ability include 2-ethylhexyl paramethoxycinnamate (EHMC), 2-ethylhexyl salicylate, hydroxymethoxybenzophenone sulfonic acid and its hydrate (oxybenzone-4), and 2-cyano-3,3-diphenyl-2-propenoic acid 2-ethylhexyl ester (octocrylene).

[0018] In the ultraviolet protection agent of the present invention, the blending amount of the MMPC microparticles and the ultraviolet absorber having UVA absorption ability can be, for example, in a mass ratio of MMPC microparticles:ultraviolet absorber having UVA absorption ability=5:1 to 1:5, for example, 5:1 to 1:3, or 5:1 to 1:1, etc.

[0019] <Metal oxide fine particles> The ultraviolet protection agent according to the present invention may contain metal oxide fine particles having an average particle size of 1 to 1,000 nm.

[0020] Metal oxide fine particles can be used as an ultraviolet scattering agent in the technical field, and for example, fine particles of a metal oxide selected from the group consisting of aluminum oxide, titanium oxide, zinc oxide, and zirconium oxide can be used. These may be used alone or in combination of two or more kinds, or may be a composite oxide of two or more kinds of metals. The shape of the metal oxide fine particles is not particularly limited, and may be, for example, spherical, polyhedral, angular, hollow, core-shell, porous, rod-like, plate-like, or irregular.

[0021] In addition, the metal oxide fine particles are preferably surface-treated to be hydrophilic, since this improves the dispersibility in water, and the hydrophilic treatment can be carried out by a conventional method. For example, the surface of the fine particles may be coated with silica.

[0022] The metal oxide fine particles used in the present invention are preferably fine particles whose surfaces are coated with silica. For example, silica-coated titanium oxide or silica-coated zinc oxide that has been microparticulated to an average particle size of 1 to 1000 nm can be used.

[0023] The amount of metal oxide fine particles is not particularly limited, and can be, for example, 1 to 200% by mass, 20 to 100% by mass, or 30 to 50% by mass, based on the amount (mass) of the MMPC. If the amount of metal oxide fine particles is small, the desired ultraviolet scattering effect cannot be obtained, i.e., the benefit of the incorporation cannot be obtained, and if the amount is too large, it may cause white residue when applied to the skin, and may deteriorate the feeling of use.

[0024] <Surfactants> The ultraviolet protection agent according to the present invention may contain a surfactant. The use of a surfactant can enhance the dispersibility of the MMPC fine particles and metal oxide fine particles in water, and can maintain the dispersed state stably and satisfactorily. The surfactants that can be used in the present invention are not particularly limited, but taking into consideration application to topical skin preparations, examples of surfactants that have low skin irritation and low toxicity, such as nonionic surfactants, can be mentioned. Specific examples include polyglycerin fatty acid esters, polyoxyethylene glycerin fatty acid esters, polyoxyethylene sorbitan fatty acid esters, polyoxyethylene sorbit fatty acid esters, polyoxyethylene hydrogenated castor oil, polyoxyethylene alkyl ethers, polyoxyethylene polyoxypropylene alkyl ethers, polyethylene glycol fatty acid esters, alkyl (poly)glucosides, alkyl alkanolamides, etc. Among these, polyoxyethylene sorbitan monooleate (20EO), polyoxyethylene hydrogenated castor oil, decyl glycoside, polyglyceryl laurate, polyoxyethylene lauryl ether, polyethylene glycol monolaurate, etc. can be mentioned, which are also suitable from the viewpoint of being liquid at room temperature. The HLB value of the surfactant can be, for example, 10 or more, taking into consideration dispersion in water.

[0025] The amount of the surfactant is not particularly limited, but may be, for example, 1 to 100% by mass, or 5 to 30% by mass, relative to the amount (mass) of the MMPC. If the amount of the surfactant is too small, the desired effect of improving dispersibility cannot be obtained, and if the amount is too large, it may cause stickiness when applied to the skin, thereby worsening the feel when used.

[0026] [External skin preparations] The UV protection agent of the present invention is suitable for use in external preparations for the skin, and such external preparations for the skin are also within the scope of the present invention. When the UV protection agent of the present invention is incorporated into a topical skin preparation, the amount to be incorporated may be determined appropriately depending on the desired UV absorption ability, but typically, the combined amount of MMPC microparticles and UV absorber having UVA absorption ability can be incorporated in an amount, for example, of 0.001 to 30% by mass, 0.01 to 15% by mass, or 1 to 15% by mass, relative to the total mass of the topical skin preparation.

[0027] The skin topical preparation of the present invention can be applied without being limited to the forms that have been used so far in medicines, quasi-drugs, cosmetics, etc. For example, the product forms include ointments, creams, milky lotions, liquids, gels, sprays, and patches, and can also be applied to various medicines, quasi-drugs, and cosmetics, such as lotions, beauty serums, sunscreens, lipsticks, face colors, eyeliners, hair sprays, hair tonics, and hair liquids.

[0028] In addition to the MMPC microparticles, ultraviolet absorbers having UVA absorbing ability, metal oxide microparticles, and surfactants, the topical skin preparations of the present invention can contain ingredients that can usually be incorporated into pharmaceuticals, quasi-drugs, and cosmetics, such as ultraviolet absorbers other than MMPC, water-soluble bases, solvents, moisturizers, water-soluble polymers, thickeners, oils and fats, hydrocarbons, higher fatty acids, higher alcohols, lower alcohols, polyhydric alcohols, esters, silicones, film-forming agents, chelating agents, sugars, amino acids, organic amines, pH adjusters, stabilizers, antioxidants, fragrances, colorants, etc.

[0029] <Water-soluble base> The water-soluble base is expected to improve the dispersibility of the MMPC microparticles. Water-soluble bases that can be used in the present invention are not particularly limited, but examples thereof include alcohols and glycols such as ethanol, polyethylene glycol, propylene glycol, 1,3-butylene glycol, dipropylene glycol, glycerin, and sorbitol; water-soluble polymers such as carrageenan, xanthan gum, pectin, pullulan, methyl cellulose, ethyl cellulose, methylhydroxypropyl cellulose, hydroxyethyl cellulose, carboxyvinyl polymer, (acrylates / alkyl acrylate (C10-30)) crosspolymer, and acrylates copolymer; etc. The water-soluble polymers also function as thickeners. EXAMPLES

[0030] The present invention will be described in more detail below with reference to examples of the present invention, but the present invention is not limited to these. Note that all blend amounts are shown in mass %.

[0031] [Reference example 1] 50 g of 2-methylphenyl paramethoxycinnamate crystals and 450 g of purified water were mixed to obtain a mixture, which was then wet-pulverized and dispersed in two stages using a bead mill (Labostar (registered trademark) Mini LMZ015, Ashizawa Finetech Co., Ltd.) with zirconia beads of diameters of 0.1 mm and 0.05 mm to obtain a white dispersion containing dispersed MMPC fine particles.

[0032] The particle size distribution of the resulting white dispersion containing dispersed MMPC particles was measured using a particle size distribution analyzer, Microtrack UPA150ST (dynamic light scattering (DLS) method), manufactured by Microtrack Bell Co., Ltd. (formerly Nikkiso Co., Ltd.). The particle size distribution of the MMPC crystals before milling was measured using a Microtrack MT3300EXII (laser diffraction / scattering method). FIG. 1 shows the particle size distribution of the MMPC crystals before grinding, and FIG. 2 shows the particle size distribution of the white dispersion (MMPC fine particles after grinding). As shown in Figs. 1 and 2, the MMPC crystals before milling have a particle size of approximately 10 µm to 500 µm, and the 50% by volume particle size in the cumulative frequency distribution (D 50 ) is 104.9 μm (Figure 1), whereas the MMPC fine particles after crushing have a particle size of approximately 50 nm to 2000 nm, and the 50% particle size in the cumulative frequency distribution (D 50 ) was confirmed to be 263 nm (Figure 2).

[0033] [Example 1 to Example 5] The ingredients were mixed according to the formulations shown in Tables 1 and 2 below to obtain emulsions of Examples 1 to 5. For the obtained emulsions of Examples 1 to 5, the SPF values ​​were measured in vitro based on the following <UV protection effect: evaluation method>. The results are shown in Table 2.

[0034] <UV Inhibition Effect: Evaluation Method> The resulting formulation was diluted to 1.3 mg / cm 2The solution was evenly applied onto a Helioplate HD6 (manufactured by Helioscreen) so that the solution was as shown in the figure, and the sample was placed evenly in small spots. The sample was then spread lightly for the first 30 seconds, and then rubbed in vigorously for the remaining 30 seconds. The solution was then left in a dark place for 15 minutes to prepare the measurement sample. The SPF value was measured in vitro using an SPF analyzer (SPF-290S, manufactured by Optometrics).

[0035] [Table 1]

[0036] [Table 2]

[0037] As shown in Table 2, the UVA absorber methylene bisbenzotriazolyl tetramethylbutylphenol ( MBBT The SPF value of the emulsion of Example 2, which contains 50% Tinosorb M, is 4.47. The SPF value of the emulsion of Example 3, which contains mortar-ground MMPC, is 7.11. The SPF value of the emulsion of Example 4, which contains 50% MMPC fine particles (50 volume % particle diameter (D 50 The lotion of Example 4, which contained MMPC microparticles and Tinosorb M, had an SPF value of 42.43. The lotion of Example 5, which contained MMPC microparticles and Tinosorb M, had an SPF value of 56.32. Compared with Examples 2 and 4, it was confirmed that the combined use of these products synergistically improved the SPF value.

[0038] [Example 6 to Example 7] Using an ointment base, MMPC microparticles (D 50 The ointment of Example 6 was prepared containing MMPC (2.5% by mass), BMDBM (1.5% by mass), and titanium oxide (7.5% by mass). In addition, the ointment of Example 7 was prepared using the same ingredients and procedures as in Example 6, except that the MMPC microparticles in the ointment of Example 6 were replaced with 2.5 mass% of 2-ethylhexyl 4-methoxycinnamate (EHMC), a general-purpose UVB absorber.

[0039] The UV protection spectra of the ointments of Examples 6 and 7 are shown in Figure 3. In Figure 3, the horizontal axis indicates the absorption wavelength, and the vertical axis indicates the reciprocal of the transmittance (MPF). As shown in FIG. 3, in Example 6, in which MMPC and BMDBM were used in combination, the MPF was 10 or more over the wavelength range of 320 nm to 360 nm, that is, the amount of transmitted light in this wavelength range was 10% or less of the incident light (see the shaded area in FIG. 3). On the other hand, in Example 7, in which EHMC was used in place of MMPC in combination with BMDBM, an MPF ​​of 10 or more could not be achieved over the wavelength range of 320 nm to 360 nm.

[0040] [Examples 8 to 11, 12 to 15] The components were mixed according to the formulations shown in Table 3 or Table 4 below to obtain emulsions of Examples 8 to 11 and Examples 12 to 15. In the examples shown below, the MMPC microparticles could be blended in the form of an aqueous dispersion of MMPC microparticles. For the obtained emulsions of Examples 8 to 11 and Examples 12 to 15, the SPF values ​​were measured in vitro using an SPF analyzer (SPF-290S, manufactured by Optometrics) in the same manner as in the above <UV protection effect: evaluation method>. In addition, for Examples 12 to 15, the UVA / UVB ratio (UVA (320 to 400 nm) and UVB (290 The ratio of absorbance at 100 nm to 320 nm was calculated. The results obtained are shown in Tables 3 and 4, respectively.

[0041] [Table 3]

[0042] [Table 4]

[0043] As shown in Table 3, it was confirmed that the SPF value tended to increase depending on the amount of MMPC microparticles blended. As shown in Table 4, this formulation showed the maximum SPF value at a concentration where the MMPC microparticle content was about 8%. In addition, the UVA / UVB ratio was close to 0.5 for all formulations, confirming that these are formulations with ultraviolet absorbing capabilities over a wide absorption range.

[0044] [Examples 16 to 19, 20 to 23] The ingredients were mixed according to the formulations shown in Table 5 or Table 6 below to obtain emulsions of Examples 16 to 19 and Examples 20 to 23. The SPF values ​​of the obtained emulsions of Examples 16 to 19 and Examples 20 to 23 were measured in vitro using an SPF analyzer (SPF-290S, manufactured by Optometrics) in the same manner as in the above <UV protection effect: evaluation method>. In addition, for Examples 20 to 23, the UVA / UVB ratio (the ratio of absorbance of UVA (320 to 400 nm) to UVB (290 to 320 nm)) was calculated. The results obtained are shown in Tables 5 and 6, respectively.

[0045] [Table 5]

[0046] [Table 6]

[0047] As shown in Table 5, Tinosorb M ( MBBT It was confirmed that the SPF value tended to increase depending on the amount of MBBT (MBBT content: 0-3%). As shown in Table 6, this formulation (MBBT content: 0-4.5%) showed the maximum SPF value at a concentration where the MBBT content was about 3%. Also, it was confirmed that Examples 21 to 23 had a UVA / UVB ratio close to 0.5, making them formulations with ultraviolet absorbing ability over a wide absorption range.

[0048] [Example 24 to Example 26] The ingredients were mixed according to the formulation shown in Table 7 below to obtain creams of Examples 24 to 26. For the obtained creams of Examples 24 to 26, the SPF values ​​were measured in vitro using an SPF analyzer (SPF-290S, manufactured by Optometrics) in the same manner as in the above <UV protection effect: evaluation method>, and the UVA / UVB ratio (the ratio of absorbance of UVA (320-400 nm) to UVB (290-320 nm)) was calculated. The results are also shown in Table 7.

[0049] [Table 7]

[0050] As shown in Table 7, in this formulation, the preparations of Examples 24 and 25 showed high SPF values ​​even at a concentration of 5% MMPC microparticles, and the UVA / UVB was approximately 0.5±0.1, confirming that these are preparations with ultraviolet absorbing ability over a wide absorption range. On the other hand, the SPF value of Example 26, which contained 2-ethylhexyl 4-methoxycinnamate (EHMC), a general-purpose UVB absorber, instead of MMPC microparticles, was inferior to the SPF value of Example 25, which contained the same amount of MMPC microparticles, and was also lower than the SPF value of Example 24, which contained 5% MMPC microparticles.

Claims

1. 50% by volume particle diameter in cumulative frequency distribution (D ５０ 2-methylphenyl paramethoxycinnamate (MMPC) microparticles having a diameter of 50 to 1,000 nm; methylene bisbenzotriazolyl tetramethylbutylphenol (MBBT); and water.

2. The MMPC microparticles have a 50% by volume particle diameter (D ５０ ) is 100 to 500 nm; The ultraviolet protection agent according to claim 1 .

3. The MMPC microparticles and methylene bisbenzotriazolyl tetramethylbutylphenol (MBBT) are contained in a mass ratio of 5:1 to 1:

5. The ultraviolet protection agent according to claim 1 or 2.

4. The ultraviolet protection agent according to claim 1 , further comprising metal oxide fine particles having an average particle size of 1 to 1,000 nm.

5. The ultraviolet protection agent according to claim 1 , further comprising a surfactant.

6. The MMPC microparticles are in the form of an aqueous dispersion of MMPC microparticles. The ultraviolet protection agent according to any one of claims 1 to 5.

7. 7. A skin external preparation comprising the ultraviolet protection agent according to claim 1.

8. The external skin preparation according to claim 7, which is a cosmetic preparation.

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