Organic ultraviolet blocking agent capsule having effect of improving ultraviolet blocking efficiency

Abstract

The invention relates to an organic ultraviolet blocking agent inorganic encapsulation technology for improving aging stability and ultraviolet blocking efficiency and a preparation method of the organic ultraviolet blocking agent inorganic encapsulation technology. According to the present invention, the organic UV filtering agent is encapsulated through the encapsulation reaction of the encapsulation component, and the stabilization condition of the prepared microcapsule emulsion is achieved, such that the high temperature and the aging stability can be ensured.

Description

Technical Field

[0001] The invention relates to an organic ultraviolet blocking agent capsule with excellent ultraviolet blocking efficiency. Background Art

[0002] Due to the depletion of the ozone layer caused by environmental pollution, the amount of ultraviolet rays has increased, and as the number of people who enjoy outdoor sports such as golf, mountain climbing, and fishing has increased, the demand for ultraviolet blockers has increased significantly. In particular, the demand for maintaining healthy skin from skin cancer to aging is increasing, and a lot of research on ultraviolet blockers is being carried out to meet these demands.

[0003] Organic UV filters in UV blockers absorb UV rays and prevent them from penetrating the skin. However, since UV filters may cause skin irritation and penetrate into the skin, various technologies for encapsulating organic UV filters have been published to prevent this.

[0004] A typical encapsulation method is to mix an oil phase consisting of an organic UV blocker and a silica precursor in an aqueous phase dispersed with a surfactant, and prepare a core-shell structure capsule in which the organic UV blocker is surrounded by silica through high-speed emulsification and silica reaction.

[0005] At this time, the capsules exist in the form of an emulsion dispersed in the aqueous phase. However, as time passes, the capsules aggregate to form curds or react with silanol remaining in the aqueous phase to gel in the solvent, making it difficult to ensure the stability of the capsules over time.

[0006] Therefore, the prior art requires surface treatment of the capsule surface, or additional freeze drying and powdering and redispersion in a solvent. As an example, the patent publication JP2007-501143 proposes a method of encapsulating an organic UV filter, freeze drying and powdering, and mixing it into a binder again when applied to a dosage form.

[0007] The present invention therefore aims to produce microcapsules containing organic UV filters and to ensure the high temperature and time stability of the microcapsules.

[0008] [Prior art literature]

[0009] [Patent Document]

[0010] 1. Japanese Patent Publication No. 2007-501143 Summary of the invention

[0011] Technical issues

[0012] The present invention relates to microcapsules with improved temporal stability and ultraviolet blocking efficiency and a preparation method thereof.

[0013] Technical Solution

[0014] The present invention provides a method for preparing microcapsules, comprising:

[0015] a step of mixing a continuous phase comprising an emulsifier with a dispersed phase comprising an organic UV filter and an encapsulated ingredient to prepare an emulsion;

[0016] a step of correcting the difference in specific gravity between the continuous phase and the dispersed phase; and

[0017] The step of adding an organic acid to the emulsion.

[0018] In addition, the present invention provides a microcapsule prepared by the above preparation method.

[0019] In addition, the present invention provides a method for preparing microcapsules, comprising the step of mixing a continuous phase containing an emulsifier with a dispersed phase containing an organic UV filter and an encapsulated component to prepare an emulsion, characterized in that it comprises:

[0020] a step of correcting the difference in specific gravity between the continuous phase and the dispersed phase; and

[0021] The step of adding an organic acid to the emulsion.

[0022] Effects of the Invention

[0023] In the present invention, by preparing microcapsules encapsulating an organic UV filter, the ultraviolet blocking efficiency can be improved and the temporal stability of the capsule can be ensured. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 is a schematic diagram of a method for preparing microcapsules according to an example of the present invention.

[0025] Figure 2 are photographs of microcapsules prepared in Examples and Comparative Examples of the present invention.

[0026] Figure 3 : is a graph showing the skin absorbability of sunscreens according to whether or not the microcapsules of the present invention are included. DETAILED DESCRIPTION

[0027] The present invention relates to a method for preparing microcapsules, comprising:

[0028] a step of mixing a continuous phase containing an emulsifier with a dispersed phase containing an organic UV filter and an encapsulated ingredient to prepare an emulsion (hereinafter, step 1); and

[0029] a step of correcting the difference in specific gravity between the continuous phase and the dispersed phase (hereinafter, step 2); and

[0030] A step of adding an organic acid to the emulsion (hereinafter referred to as step 3).

[0031] Hereinafter, the configuration of the present invention will be described in detail.

[0032] When it is said that a certain part “comprises” a certain constituent element, this means that other constituent elements may be further included, rather than excluding other constituent elements, unless otherwise specifically stated.

[0033] In the present invention, step 1 is a step of preparing an emulsion by mixing a continuous phase and a dispersed phase.

[0034] In the present invention, the continuous phase contains an emulsifier. The emulsifier can promote the encapsulation reaction of the encapsulation component described below.

[0035] In a specific example, the emulsifier may include a tertiary amine cationic surfactant. The above-mentioned tertiary amine cationic surfactant may be one or more selected from the group consisting of DTAB (dodecyltrimethylammonium bromide), TTAB (tetradecyltrimethylammonium bromide), CTAB (cetyltrimethylammonium bromide), CTMS (cetyltrimethylammoniummethosulfate), STMS (stearyltrimethylammoniummethosulfate), BTMS (behentrimoniummethosulfate) and dipalmitoylethyl dimonium chloride. In the present invention, as an emulsifier, dipalmitoylethyl dimonium chloride (dipalmitoylethyl dimonium chloride) can be used, that is, Quat EQG. The dipalmitoyloxyethyl dimethyl ammonium chloride can not only promote the encapsulation reaction of the encapsulation component, but also further improve the temporal stability of the prepared microcapsules.

[0036] In a specific example, the content of the above-mentioned emulsifier is not particularly limited, and can be 0.05 to 5% by weight, 1 to 3% by weight, or 1 to 2% by weight relative to the total weight of the components used in the preparation of the microcapsules. If the content is less than 0.05% by weight, there is a concern that capsules may agglomerate, and if it exceeds 5% by weight, a large amount of foam may be generated during the preparation of the emulsion, resulting in capsule emulsification or failure of capsules to form normally. Within the above content range, the dispersion stability of the emulsion can be ensured by preventing the coalescence of the above-mentioned microcapsules.

[0037] In a specific example, the solvent of the continuous phase is not particularly limited as long as it can dissolve the emulsifier, and water can be used in the present invention.

[0038] In the present invention, the dispersed phase comprises the organic UV filters and the encapsulated ingredients.

[0039] In the present invention, the organic UV filter refers to a component including an organic compound that blocks or absorbs ultraviolet rays, and may refer to an organic ultraviolet blocking component commonly used in the art.

[0040] The organic UV filter is used as an active ingredient. The active ingredient is a substance that is expected to maintain its activity through the generated capsule, and the active ingredient can then express its activity by destroying the outer wall of the capsule. In the present invention, as an active ingredient, in addition to the organic UV filter, one or more selected from the group consisting of additional ultraviolet blocking ingredients, fragrances, dyes, catalysts and drugs may be further included.

[0041] In a specific example, the organic UV filter can be selected from ethylhexyl salicylate, avobenzone, p-aminobenzoic acid, bemotrizinol, benzophenone-9, bexophenome-3, bisoctrizole, 3-(4-methylbenzylidene)-camphor, cinoxate, diethylamino hydroxybenzoylhexyl benzoate, dioxybenzone, drometrizole trisiloxane, ecamsule, ethylhexyl triazone, and 1,2-dihydroxybenzoyl benzoate. At least one selected from the group consisting of triazone, homosalate, menthyl anthranilate, octocrylene, octyl salicylate, isotrizinol, isopentenyl-4-methoxycinnamate, octyl-dimethyl-p-aminobenzoic acid, octyl-methoxycinnamate, oxybenzone, polysilicone-15 and trolamine salicylate.

[0042] In a specific example, the content of the organic UV filter is not particularly limited, and can be used in an amount of 1 to 80 wt %, 3 to 65 wt %, or 5 to 50 wt % relative to the total weight of the components used in the preparation of the microcapsules.

[0043] In the present invention, the encapsulating component may constitute the outer wall (ie, shell) of the microcapsule. These encapsulating components may include one or more selected from the group consisting of a silica precursor, a titania precursor, and a zirconia precursor.

[0044] In a specific example, the encapsulated component may include one or more compounds selected from the group consisting of compounds represented by the following Chemical Formulas 1 to 4.

[0045] [Chemical formula 1]

[0046]

[0047] [Chemical formula 2]

[0048]

[0049] [Chemical formula 3]

[0050]

[0051] [Chemical formula 4]

[0052]

[0053] In the above chemical formulas 1 to 4, A may be silicon, titanium or zirconium, R1 to R4 may each independently be hydrogen or an alkyl group having 1 to 8 carbon atoms with a terminal substituted or unsubstituted functional group, and the above functional group may include amine, hydroxyl, amide, carboxyl, vinyl, epoxy, phenyl or mercapto, etc.

[0054] In a specific example, the silica precursor may include one or more selected from the group consisting of tetraethyl orthosilicate (TEOS), tetramethyl orthosilicate, tetrapropyl orthosilicate, tetrabutyl orthosilicate, dimethyldimethoxysilicate, trimethylmethoxysilicate, methyltrimethoxysilicate, trimethylethoxysilicate, butyltrimethoxysilicate, N-propyltrimethoxysilane, N-octyltrimethoxysilane, aminopropyltrimethoxysilicate, phenyltrimethoxysilane and 3-mercaptopropyltrimethoxysilane.

[0055] In a specific example, the titanium oxide precursor may include one or more selected from the group consisting of titanium methoxide, titanium ethoxide, and titanium butoxide.

[0056] In addition, in a specific example, the zirconium oxide precursor may include one or more selected from the group consisting of zirconium methoxide, zirconium ethoxide, and zirconium butoxide.

[0057] In a specific example, the content of the encapsulation component is not particularly limited, and can be 0.001 to 30 wt%, 0.01 to 25 wt%, or 0.1 to 20 wt% relative to the total weight of the components used in the preparation of the microcapsules. If the content of the encapsulation component is less than 0.001 wt%, there is a concern that even if the encapsulation reaction occurs, the outer wall of the capsule is formed too thin to be maintained, and if it exceeds 30 parts by weight, there is a concern that the distinction between the dispersed phase and the continuous phase becomes blurred, thereby causing a problem that the capsule cannot be formed.

[0058] In a specific example, a silica precursor, a titania precursor, and a zirconia precursor can be converted into silica, titania, and zirconia, respectively, through an encapsulation reaction.

[0059] In a specific example, the solvent of the dispersed phase is not particularly limited as long as it is a solvent that is not mixed and miscible with the continuous phase. When water is used as the solvent of the continuous phase, the solvent of the dispersed phase can be selected from the group consisting of hydrocarbon solvents; solvents containing ether groups; solvents containing ester groups; solvents containing ketone groups; solvents containing benzene; halogenated alkane solvents; and silicone solvents.

[0060] The hydrocarbon solvent can be selected from compounds with linear or nonlinear structures, such as pentane, hexane, cyclohexane, heptane, octane, isododecane and dodecane, the solvent containing an ether group can be selected from ethyl ether, butyl ether and methyl-t-butyl ether, and the solvent containing an ester group can be selected from ethyl acetate, butyl acetate and ethyl butyrate. In addition, the solvent containing a ketone group may be methyl ethyl ketone, the solvent containing benzene may be selected from benzene, toluene and xylene, the haloalkane type solvent may be selected from dichloromethane, dichloroethane, chloroform and carbon tetrachloride, and the silicone type solvent may be selected from dimethicone and cyclomethicone.

[0061] In the present invention, the emulsion may be prepared by mixing the above-mentioned continuous phase and dispersed phase.

[0062] In a specific example, the content of the dispersed phase may be 1 to 60 parts by weight, 2 to 50 parts by weight, or 3 to 40 parts by weight based on the mixed weight (100 parts by weight) of the dispersed phase and the continuous phase.

[0063] In a specific example, the step 1 can be performed by adding the dispersed phase to the continuous phase, and the step can be performed under stirring.

[0064] In one embodiment, the stirring may be performed at 1 to 16,000 RPM, 5 to 13,000 RPM, or 10 to 10,000 RPM at 20 to 30° C., or at room temperature.

[0065] In the present invention, step 2 is a step of correcting the difference in specific gravity between the continuous phase and the dispersed phase. Through the above steps, the specific gravity can be corrected to be similar to that of the continuous phase, thereby solving the problem of floating or sedimentation.

[0066] Microcapsules containing organic UV filters are in a form of being emulsified and dispersed in an aqueous phase (i.e., continuous phase) solvent by an emulsifier. At this time, there is a difference in specific gravity between the capsules and the aqueous phase solvent, so that the capsules sink or float on the top, resulting in a problem of stability over time. In addition, if the capsules float or sink, the microcapsules begin to aggregate, the emulsion gels, and a curd is formed.

[0067] In the present invention, in order to prevent this phenomenon, a sugar compound or oil can be added to the emulsion to correct the specific gravity difference. Alternatively, the specific gravity difference can be adjusted by adding the sugar compound or oil to the dispersed phase before preparing the emulsion. By correcting the specific gravity difference, the temporal stability of the capsule can be ensured.

[0068] In a specific example, the type of the above-mentioned sugar compound is not particularly limited, and one or more selected from the group consisting of monosaccharides of fructose, glucose, galactose, mannoheptulose and sedoheptulose; disaccharides of sucrose, lactose, maltose, trehalose and cellobiose; and polysaccharides of cellulose, starch, glycogen, chitin, arabinoxylan and pectin can be used.

[0069] In a specific example, the content of the sugar compound is not particularly limited and may vary according to the specific gravity of the ingredients used in the preparation of the microcapsules. If the specific gravity of the capsule is greater than the continuous phase, the capsule may sink, and if the specific gravity of the capsule is less than the continuous phase, a phenomenon of creaming may occur in which the capsule floats on the top. At this time, if the specific gravity of the capsule is greater than the continuous phase and precipitation occurs, the precipitation of the capsule can also be prevented by increasing the specific gravity of the continuous phase by the sugar compound. For example, the content of the above-mentioned sugar compound may be 0.001 to 30% by weight, 0.5 to 20% by weight, or 1 to 10% by weight relative to the total weight of the ingredients used in the preparation of the microcapsules.

[0070] In a specific example, the type of the above-mentioned oil is not particularly limited as long as it is an oil component that can be generally used in human products. Specifically, the above-mentioned oil can use one or more of the oils that can be generally used in human products, such as vegetable oils, hydrocarbon oils, ester oils, silicone oils and synthetic oils. As a specific example of the above-mentioned oil, it can be selected from green tea seed oil, argania spinosa kernel oil, olive oil, sunflower seed oil, jojoba seed oil, camellia seed oil, Queensland macadamia nut oil (Macadamia Integrifolia Nut Oil) Oil), monascus extract, sweet almond oil, castor oil, octyldodecanol, polyglyceryl-2 triisostearate, diisostearyl malate, cetyl ethylhexanoate, tridecyl trimellitate, squalane, trioctyldodecanol citrate, pentaerythrityl tetraisostearate, caprylic / capric triglyceride, caprylyl methicone, diphenyl dimethicone, diphenylsiloxyphenyl trimethicone, isostearic acid, dicaprylyl carbonate, C12-15 alkyl benzoate, dibutyl adipate, isononyl isononanoate, isodecyl neopentanoate phytosteryl / isostearyl / cetyl / stearyl / behenyl dimer dilinoleate Dimerdilinoleate), Shea Butter, Ethylhexyl Methoxycinnamate, Stearalkonium Hectorite, Acrylates / Dimethicone Copolymer, Polyisobutene, Hydrogenated Polyisobutene, Hydrogenated Castor Oil Dimer Linoleate, Polyglyceryl-2 Isostearate / Dimer Linoleate Copolymer, Bis-behenyl / isostearyl / phytosteryl dimer dilinoleyl dimer dilinoleate, Hydrogenated Castor Oil Isostearate, Macadamia Ternifolia Seed Oil, Polyglyceryl-6 Esters Behenate, Limnanthes Da-lactone, Jojoba Esters, Dipentaerythrityl Hexahydroxystearate / Hexastearate / Hexarosinate At least one of the group consisting of hexahydroxystearate / hexastearate / hexarosinate), dimer linoleic acid / butylene glycol copolymer, ethylene / propylene / styrene copolymer, butylene / ethylene / styrene copolymer, petroleum grease, polydimethylsiloxane crosspolymer and polydimethylsiloxane / vinyl polydimethylsiloxane crosspolymer. Preferably, two or more oils with different specific gravities among the above oils can be mixed to adjust the specific gravity difference.For example, the oil may be contained in an amount of 0.001 to 30 wt %, 0.5 to 20 wt %, or 1 to 10 wt % relative to the total weight of the ingredients used in the preparation of the microcapsules.

[0071] In a specific example, the above step 1 and the above step 2 can be performed simultaneously.

[0072] In the present invention, the emulsion can be encapsulated just after preparation, and the encapsulation can be continued until the reactive groups of the capsule wall disappear. As an example, the encapsulation is a sol-gel reaction in which a silica precursor is cured into silica, and the sol-gel reaction can be used in the sense of a hydrolysis and curing reaction of the silica precursor. Specifically, the encapsulation of the silica precursor can form silanol by a hydrolysis reaction and cure the silanol by a condensation reaction.

[0073] In the present invention, as a step before step 3 described later, a step of aging the emulsion may be further included. The aging process can provide sufficient conditions for forming a shell as the outer wall of the microcapsule, thereby ensuring the durability of the microcapsule and making it less likely to be broken by external pressure.

[0074] In a specific example, the aging may be performed at 20 to 30° C. or at room temperature for 1 to 10 days, 1 to 5 days, or 2 to 4 days.

[0075] In the present invention, step 3 is a step of adding an organic acid to the emulsion. In the present invention, the organic acid can be used to improve the stability of the microcapsules.

[0076] It is known that in the encapsulation reaction, if the reaction environment is acidic, the condensation reaction is dominant over the hydrolysis reaction, and if the reaction environment is alkaline, the hydrolysis reaction is dominant.

[0077] As an example, in the present invention, by adding an appropriate amount of organic acid to the emulsion, the condensation reaction can be promoted, and the curing reaction of silanol on the capsule wall can be dominated, thereby improving the stability of the capsule.

[0078] In a specific example, the type of organic acid is not particularly limited, and one or more selected from the group consisting of citric acid, lactic acid, acetic acid, formic acid, oxalic acid, succinic acid, carbonic acid, benzoic acid, acetic acid, ascorbic acid, carboxylic acid, sulfinic acid, sulfonic acid, fumaric acid, malic acid, butyric acid, propionic acid and stearic acid can be used.

[0079] In a specific example, the content of the organic acid is not particularly limited, and may be 0.05 to 10 wt%, 0.3 to 8 wt%, or 0.5 to 5 wt% relative to the total weight of the components used in the preparation of the microcapsules. If it is less than 0.05 wt%, gelation of the emulsion will occur, and if it exceeds 10 wt%, the acidity of the emulsion will increase, and the hydrolysis reaction of the silica precursor will dominate, resulting in the inability to firmly form the capsule wall, so there is a concern that the stability of the microcapsules will be reduced.

[0080] In the present invention, microcapsules can be prepared by the above steps. Specifically, when a silica precursor is used as an encapsulation component, such as Figure 1 As shown, a stable microcapsule containing an active ingredient can be prepared by hydrolysis and curing reaction of a silica precursor at the interface between a continuous phase and a dispersed phase. Specifically, since the silica precursor contains an alkoxy group, it is initially mixed in the dispersed phase as a core material, but if hydrolysis occurs at the emulsion interface, the silica precursor becomes hydrophilic and accumulates at the interface. During this process, a curing reaction occurs to form a solid outer wall.

[0081] In the present invention, the stability of microcapsules can be improved by using organic acids, so that the prepared capsule emulsion can ensure high temperature and time stability by itself without the need for additional processes of surface treatment of the capsule surface and / or freeze drying.

[0082] In addition, the present invention relates to microcapsules prepared by the above-mentioned method for preparing microcapsules.

[0083] In a specific example, the diameter of the microcapsule may be 0.01 to 500 μm, 0.1 to 100 μm, or 0.5 to 5 μm. If the diameter is less than 0.01 μm, there is a concern that the function of blocking ultraviolet rays and protecting the skin is reduced, and if it exceeds 500 μm, there is a concern that the stability is reduced due to the unity of the capsule.

[0084] In one specific example, the microcapsules according to the present invention can maintain a dispersed state for more than 2 weeks without precipitation or gelation even at a high temperature of 50°C.

[0085] In addition, the present invention relates to an ultraviolet blocker comprising the above microcapsules. The dosage form of the above ultraviolet blocker can be cream, lotion, ointment, powder, etc., and there is no limitation as long as it is a dosage form that can be used in the dosage form of ultraviolet blockers.

[0086] In a specific example, the content of the microcapsules in the ultraviolet blocker may be 0.5 to 20 parts by weight or 1 to 15 parts by weight relative to the total weight (100 parts by weight).

[0087] In addition, the present invention provides a method for preparing microcapsules, comprising the step of mixing a continuous phase containing an emulsifier with a dispersed phase containing an organic UV filter and an encapsulated component to prepare an emulsion, characterized in that it comprises:

[0088] a step of correcting the difference in specific gravity between the continuous phase and the dispersed phase; and

[0089] The step of adding an organic acid to the emulsion.

[0090] Hereinafter, the present invention will be described in detail by way of examples. The following examples are only used to illustrate the present invention, and the scope of the present invention is not limited to the following examples. This example is provided to make the disclosure of the present invention complete and to fully inform the scope of the invention to those of ordinary skill in the art to which the present invention belongs, and the present invention is defined only by the scope of the claims. The raw materials used in the present invention are purchased from raw material companies that can usually be purchased.

[0091] Implementation

[0092] Example

[0093] Example 1 and Comparative Examples 1 to 3. Preparation of microcapsules containing organic UV filters

[0094] Microcapsules of Examples and Comparative Examples were prepared according to the components and contents (weight %) described in Table 1 below.

[0095] [Table 1]

[0096]

[0097] The preparation methods of the microcapsules according to Example 1 and Comparative Example 1 are as follows.

[0098] ① Prepare a continuous phase by dissolving an emulsifier in distilled water at room temperature. At the same time, prepare a dispersed phase by mixing a silica precursor and an organic UV filter at room temperature.

[0099] ② Slowly add the dispersed phase into the continuous phase and stir at 8000 rpm for 10 minutes to form an emulsified emulsion.

[0100] ③After that, slowly add sucrose into the emulsion and stir for 30 minutes.

[0101] ④ The emulsified emulsion is aged at room temperature for 3 days.

[0102] ⑤After that, add citric acid.

[0103] The preparation methods of the microcapsules according to Example 2, Comparative Examples 2 and 3 are as follows.

[0104] ① Prepare a continuous phase by dissolving an emulsifier in distilled water at room temperature. At the same time, prepare a dispersed phase by mixing a silica precursor, oil and an organic UV filter at room temperature.

[0105] ② Slowly add the dispersed phase into the continuous phase and stir at 8000 rpm for 10 minutes to form an emulsified emulsion.

[0106] ③ The emulsified emulsion is aged at room temperature for 3 days.

[0107] ④After that, add citric acid.

[0108] Comparative Example 4. Preparation of microcapsules containing organic UV filters

[0109] Microcapsules were prepared according to the method of Example 1, except that the process of aging the emulsified emulsion at room temperature for 3 days (ie, ④ in the preparation method of Example 1) was not performed.

[0110] Experimental Example 1. Comparison of high temperature and time stability

[0111] The temporal stability of the microcapsules prepared in the above examples and comparative examples was compared.

[0112] When the microcapsules were stored at 50° C. and 50% humidity, it was observed whether gelation or precipitation occurred in the emulsion, that is, whether the microcapsules in the water phase maintained a dispersed state.

[0113] The results are shown in Table 2.

[0114] [Table 2]

[0115] distinguish Example 1 Example 2 Comparative Example 1 Comparative Example 2 Comparative Example 3 50℃ stability 2 weeks stable 2 weeks stable Day 4 Sedimentation Day 1 Sedimentation First day of floating

[0116] Immediately after preparation, the microcapsules of Examples 1 to 2 and Comparative Examples 1 to 3 all appeared in a milky white to light yellow non-viscous emulsion state. After 1 day, in Comparative Example 2, capsules precipitated out from the bottom of the emulsion and formed lumps, and in Comparative Example 1, precipitates and gels were formed on the 4th day. Since the density of the capsules of Comparative Example 3 was low, they floated on the first day. On the other hand, the microcapsules of Examples 1 and 2 did not precipitate or gel until 2 weeks at high temperature.

[0117] Based on the above results, it can be confirmed that the dosage form stability of the emulsion can be ensured by formulating the emulsifier, sugar compound and organic acid in appropriate amounts.

[0118] Experimental Example 2: Observation of the morphology of microcapsules

[0119] It was confirmed whether the microcapsules prepared in the above examples and comparative examples were normally formed. Specifically, after the microcapsules were prepared, the morphology of the microcapsules was observed using an optical microscope.

[0120] The observation results are shown in Figure 2 In. On Figure 2 In the figure, (a) shows the morphology of the microcapsules prepared in Example 1, and (b) shows the morphology of the microcapsules prepared in Comparative Example 4.

[0121] like Figure 2 As shown in FIG. 1 , it can be confirmed that the microcapsules of Example 1 form particles of uniform size of about 1 μm ( Figure 2 (a)), while for the microcapsules of Comparative Example 4 without the aging process, the silica precursor is not cured to silica and the shell is formed in a short time, so the capsule shape cannot be maintained and is easily broken ( Figure 2 (b)).

[0122] Experimental Example 3: Measurement of the average particle size of microcapsules

[0123] The average particle size of the microcapsules prepared in Examples and Comparative Examples was measured using Mastersizer 3000 (Malvern).

[0124] The average particle size was measured for the first time after the preparation of the microcapsules and for the second time 4 weeks after the preparation to confirm the particle size change, that is, the temporal stability of the capsules.

[0125] The above measurement results are shown in Table 3 below.

[0126] [Table 3]

[0127] sample Average particle size (first time, μm) Average particle size (second time, μm) Example 1.07 1.56 Comparative Example 2 2.33 5.81

[0128] As shown in Table 3, it can be confirmed that the appropriate particle size of the capsule according to the present invention is 0.5 to 5 μm in diameter, and the temporal stability of the microcapsules prepared in Comparative Example 2 is reduced.

[0129] Experimental Example 4: Evaluation of UV Blocking Index (SPF and PA)

[0130] The ultraviolet light blocking ability of the microcapsules prepared in Example 1 was confirmed.

[0131] Oil-in-water sunscreens of Preparation Examples 1 to 3 were prepared according to the ingredients and contents in Table 4 below, and their ultraviolet blocking abilities were evaluated.

[0132] In the microcapsules of Example 1 and Comparative Example 4, the content of the organic UV filter was 50 wt %, and if it was added to Preparation Examples 1 to 3 at 10 wt %, the UV filters contained in the above Preparation Examples were all the same, 5 wt %.

[0133] 1. Preparation of O / W Sunscreen

[0134] [Table 4]

[0135]

[0136] The preparation method is as follows.

[0137] 1) Components 2 (organic UV filter, ethylhexyl salicylate) and 3 were completely dissolved and dispersed at 75° C. to prepare an oil phase.

[0138] 2) Components 4 to 8 were uniformly dispersed using a disperser, and then heated to 75° C. to prepare a water phase.

[0139] 3) The oil phase was slowly added to the water phase and emulsified using a homomixer at 8,000 rpm for 10 minutes.

[0140] 4) After cooling to 50°C, component 1 was added and mixed at 5,000 rpm for 1 minute.

[0141] 5) Cool to 30°C and degas.

[0142] 2. Evaluation method of UV blocking ability

[0143] In vitro SPF values ​​were measured by the following method. The samples were concentrated at 1.3 mg / cm 2 The film was coated on a PMMA plate (HelioScreen Labs, France) with a thickness of 1000 nm, dried for 15 minutes, and then measured by SPF-290S (Optometrics Corporation, USA). The average value of the in vitro SPF and PA values ​​measured at 6 different locations on the PMMA plate was used.

[0144] The measurement results are shown in Table 5 below.

[0145] [Table 5]

[0146] project Preparation Example 1 Preparation Example 2 Preparation Example 3 SPF 7.86 14.89 7.70 PA 6.71 12.28 6.93

[0147] As shown in Table 5 above, it can be confirmed that for Preparation Example 2 containing the microcapsules of Example 1, the SPF increased by about 89% and the PA increased by about 83% compared to the UV blocking index of Preparation Example 1 without the microcapsules. This means that when the organic UV filter is encapsulated and applied to the dosage form, the UV blocking ability is greatly increased compared to the existing emulsified dosage form.

[0148] In addition, it was confirmed that Preparation Example 3, in which the capsules of Comparative Example 3 without aging were prepared, had no significant difference in ultraviolet shielding ability compared with Preparation Example 1. This means that the capsules were not formed normally and therefore had no effect as capsules.

[0149] 3. Evaluation of skin penetration of organic UV filters

[0150] The skin penetration of organic UV filters according to whether or not microcapsules were used was measured.

[0151] The sunscreens according to Preparation Examples 1 and 2 were applied to pig skin, and the penetration content of the organic UV filters was compared by skin layer.

[0152] First, PBS / EtOH (8 / 2v / v) was loaded into a Franz cell as a reservoir solution, and then pig skin 2.5 (cm) x 2.5 (cm) was placed on the upper part of the diffusion cell with keratin as the upper part, and then the upper part of the diffusion cell was clamped and fixed with a clamp. After that, a piston pipette was used to evenly apply 40μm sunscreen on the keratin. Then it was placed in a basket and incubated overnight in a constant temperature and humidity chamber at 37°C. The next day, the pig skin was peeled off, divided into each tissue (keratin, epidermis and dermis), and then a certain amount of ethanol was added and crushed with a tissue crusher. After that, the liquid was extracted and the absorbance was measured with a UV spectrometer to analyze the content of organic UV filters passed through each tissue.

[0153] The results are shown in Figure 3 middle.

[0154] like Figure 3 As shown, the amount of organic UV filter permeated in all tissue layers was very small for Preparation Example 2. It was confirmed that a large amount of organic UV filter permeated for Preparation Example 1. Thus, it was confirmed that the safety of the skin can be improved by using the microcapsules according to the present invention.

[0155] Industrial Availability

[0156] In the present invention, by preparing microcapsules encapsulating an organic UV filter, the ultraviolet blocking efficiency can be improved and the temporal stability of the capsule can be ensured.

Claims

1. A method for preparing microcapsules, comprising: a step of mixing a continuous phase comprising an emulsifier with a dispersed phase comprising an organic UV filter and an encapsulated ingredient to prepare an emulsion; a step of correcting the difference in specific gravity between the continuous phase and the dispersed phase; and The step of adding an organic acid to the emulsion.

2. The method for preparing microcapsules according to claim 1, wherein: Emulsifiers include tertiary amine type cationic surfactants.

3. The method for preparing microcapsules according to claim 1, wherein: The emulsifier includes one or more selected from the group consisting of DTAB (Dodecyltrimethylammoniumbromide), TTAB (Tetradecyltrimethylammoniumbromide), CTAB (Cetyltrimethylammoniumbromide), CTMS (Cetyltrimethylammoniummethosulfate), STMS (Stearyltrimethylammoniummethosulfate), BTMS (BehentrimoniumMethosulfate) and DipalmitoylethylDimoniumChloride.

4. The method for preparing microcapsules according to claim 1, wherein: The emulsifier is present in an amount of 0.05 to 5% by weight relative to the total weight of the ingredients used in the preparation of the microcapsules.

5. The method for preparing microcapsules according to claim 1, wherein: The encapsulated component includes one or more selected from the group consisting of a silica precursor, a titania precursor, and a zirconia precursor.

6. The method for preparing microcapsules according to claim 1, wherein: The specific gravity difference is corrected by adding a sugar compound or oil in the step of correcting the specific gravity difference between the continuous phase and the dispersed phase.

7. The method for preparing microcapsules according to claim 6, wherein: The sugar compound includes one or more selected from the group consisting of monosaccharides of fructose, glucose, galactose, mannoheptulose and sedoheptulose; disaccharides of sucrose, lactose, maltose, trehalose and cellobiose; and polysaccharides of cellulose, starch, glycogen, chitin, arabinoxylan and pectin.

8. The method for preparing microcapsules according to claim 6, wherein: The content of the sugar compound is 0.001 to 30% by weight relative to the total weight of the ingredients used in the preparation of the microcapsules.

9. The method for preparing microcapsules according to claim 1, wherein: Further comprising the step of aging the emulsion before adding the organic acid.

10. The method for preparing microcapsules according to claim 9, wherein: Aging is performed at 20 to 30°C for 1 to 10 days.

11. The method for preparing microcapsules according to claim 1, wherein: The organic acid includes one or more selected from the group consisting of citric acid, lactic acid, acetic acid, formic acid, oxalic acid, succinic acid, carbonic acid, benzoic acid, acetic acid, ascorbic acid, carboxylic acid, sulfinic acid, sulfonic acid, fumaric acid, malic acid, butyric acid, propionic acid and stearic acid.

12. The method for preparing microcapsules according to claim 1, wherein: The organic acid is present in an amount of 0.05 to 10% by weight relative to the total weight of the ingredients used in the preparation of the microcapsules.

13. A microcapsule prepared by the preparation method according to claim 1, The diameter is 0.01 to 500 μm.

14. A method for preparing microcapsules, comprising the step of mixing a continuous phase comprising an emulsifier with a dispersed phase comprising an organic UV filter and an encapsulated component to prepare an emulsion, characterized in that: include: The step of correcting the difference in specific gravity between the continuous phase and the dispersed phase; as well as The step of adding an organic acid to the emulsion.

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