Method for preparing lipid nanoparticle cosmetic composition comprising ultrasonication and high-pressure homogenization steps

Abstract

The present invention relates to a method for manufacturing an LNP-type cosmetic composition, and more specifically, to a method for manufacturing an LNP-type cosmetic composition in which the LNP particle size is uniformly controlled and the retinal capture efficiency is improved by including an ultrasonic treatment step and a high-pressure homogenization step.

Description

Technology Field

[0001] The present invention relates to a method for manufacturing an LNP-type cosmetic composition, and more specifically, to a method for manufacturing an LNP-type cosmetic composition in which the LNP particle size is uniformly controlled and the retinal capture efficiency is improved by including an ultrasonic treatment step and a high-pressure homogenization step. Background Technology

[0002] Retinoids are a group of compounds collectively referring to Vitamin A and its derivatives, known to exert various effects on the physiological functions of the skin. Retinoids are widely used as active ingredients in cosmetics to exhibit anti-aging effects, such as wrinkle reduction, improved skin elasticity, and alleviation of pigmentation.

[0003] Retinal, also referred to as retinalaldehyde, is a compound corresponding to an intermediate oxidation step between retinol and retinoic acid. Since retinal requires one fewer enzymatic step for conversion to retinoic acid compared to retinol, it can exhibit biological activity more rapidly than retinol at the same concentration. The molecular structure of retinal consists of a polyene chain in which four isoprenoid units are connected to a cyclohexenyl ring and a terminal aldehyde group. The polyene chain contains multiple conjugated double bonds, and due to these structural characteristics, retinal may undergo photoisomerization, oxidative decomposition, and polymerization reactions when exposed to ultraviolet rays, heat, and oxygen.

[0004] Lipid nanoparticles (LNPs) are nanometer-sized lipid particles formed by the self-assembly of phospholipids and other lipid components in an aqueous environment, forming a continuous lipid matrix or a multi-lipid layer structure. The double-membrane structure of LNPs is similar to biological membranes and possesses both hydrophobic and hydrophilic regions, enabling the encapsulation of various active ingredients. Lipid-soluble active ingredients are encapsulated in the hydrophobic regions of the double membrane, while water-soluble active ingredients can be encapsulated in the internal aqueous phase. Lipid nanoparticles (LNPs) protect the encapsulated active ingredients from the external environment and, upon application to the skin, can facilitate transdermal delivery of the active ingredients through fusion with the skin's lipid layer.

[0005] Lecithin is a representative phospholipid source used in the manufacture of LNPs. Lecithin is extracted from sources such as soybeans and egg yolks, and consists mainly of phosphatidylcholine, as well as phosphatidylethanolamine and phosphatidylinositol. The membrane fluidity and stability of the double membrane of LNPs formed from lecithin can be controlled by the addition of cholesterol. Cholesterol can be inserted between phospholipid molecules to increase the membrane packing density and inhibit phase transitions caused by temperature changes, thereby improving the structural stability of the LNP.

[0006] Surfactants are amphiphilic compounds that adsorb to the interface between the oil and water phases, lowering interfacial energy and improving the stability of the dispersion system. Nonionic surfactants are widely used in cosmetics because they cause less skin irritation and have excellent compatibility with other ingredients compared to ionic surfactants. Polysorbates are polyoxyethylene derivatives of sorbitan fatty acid esters, and their emulsification properties can vary depending on their HLB value. Polyglyceryl fatty acid esters are esters of polyglycerin and fatty acids, and they can have various HLB values ​​depending on the degree of polymerization of the polyglycerin and the type of fatty acid.

[0007] Diols are compounds containing two hydroxyl groups within a molecule that are used in cosmetics as moisturizers, solvents, and preservative adjuvants. Propylene glycol, butylene glycol, pentylene glycol, and hexanediol are representative diols used in cosmetics. Diols contribute to maintaining skin moisture due to their high ability to form hydrogen bonds, and some diols exhibit effects that inhibit the growth of microorganisms.

[0008] Ultrasonic treatment is a process that induces cavitation by applying high-frequency sound waves to a liquid medium. The generation and collapse of microbubbles produced by cavitation generate locally high shear forces and heat, which can reduce the particle size of the dispersion system. High-pressure homogenization is a process that reduces particle size through shear forces, collisions, and cavitation by passing the dispersion system through a narrow gap under high pressure. Ultrasonic treatment and high-pressure homogenization are representative microfabrication processes used in the manufacture of nano-dispersions such as LNPs and nanoemulsions. The problem to be solved

[0009] The problem that the present invention aims to solve may be to improve the photostability and oxidation stability of retinal to ensure long-term stability within the composition.

[0010] Another problem that the present invention aims to solve may be to provide a formulation capable of maintaining dispersion stability, color stability, and particle structure while containing a high concentration of retinal.

[0011] Another problem that the present invention aims to solve may be to provide a skin-friendly composition that maintains efficacy on the skin while alleviating the skin irritation of retinal.

[0012] Another problem that the present invention aims to solve may be to stabilize the double membrane structure of LNP while suppressing particle flotation, aggregation, and separation in formulations containing high concentrations of diol and multiple surfactants.

[0013] Another problem that the present invention aims to solve may be to optimize the lipid membrane composition, aqueous composition, and surfactant combination to improve the skin penetration and absorption rate of retinal. means of solving the problem

[0014] According to one aspect of the present invention, an LNP-type cosmetic composition may be provided, comprising: retinal; a lipid membrane composition comprising lecithin, cholesterol, and lauric acid; tocopherol; a surfactant composition comprising polyglyceryl-10 oleate, polysorbate 20, and polysorbate 80; an aqueous composition comprising purified water, isopentyldiol, 1,2-hexanediol, glycerin, and sucrose; and ethylhexylglycerin, wherein the retinal is encapsulated in an LNP formed by the lipid membrane composition.

[0015] For example, an LNP-type cosmetic composition may be provided in which the content of the retinal is 0.5 to 5.0 weight% relative to the total weight of the composition.

[0016] For example, an LNP-type cosmetic composition may be provided in which the weight ratio of the lecithin, the cholesterol, and the lauric acid is 10.0 : 0.1 : 0.1 : 0.4.

[0017] For example, an LNP-type cosmetic composition may be provided in which the polyglyceryl-10 oleate, the polysorbate 20, and the polysorbate 80 are each included in an amount of 1.0 to 3.0 weight% relative to the total weight of the composition.

[0018] For example, an LNP-type cosmetic composition may be provided in which the isopentyldiol is included in an amount of 15 to 25 weight% relative to the total weight of the composition, and the 1,2-hexanediol is included in an amount of 5 to 15 weight% relative to the total weight of the composition.

[0019] For example, an LNP-type cosmetic composition may be provided in which the content of the tocopherol is 0.3 to 1.0 weight% relative to the total weight of the composition.

[0020] For example, an LNP-type cosmetic composition may be provided in which the glycerin is included in an amount of 5 to 15 weight% relative to the total weight of the composition, and the sucrose is included in an amount of 5 to 15 weight% relative to the total weight of the composition.

[0021] For example, an LNP-type cosmetic composition may be provided in which the content of the ethylhexylglycerin is 0.3 to 1.0 weight% relative to the total weight of the composition.

[0022] For example, an LNP-type cosmetic composition may be provided, wherein the average particle size of the LNP is 50 to 300 nm.

[0023] For example, an LNP-type cosmetic composition may be provided that further comprises ferulic acid.

[0024] For example, an LNP-type cosmetic composition may be provided in which the content of the ferulic acid is 0.1 to 1.0 weight% relative to the total weight of the composition.

[0025] For example, an LNP-type cosmetic composition may be provided that further comprises ascorbyl palmitate.

[0026] For example, an LNP-type cosmetic composition may be provided in which the content of the ascorbyl palmitate is 0.1 to 1.0 weight% relative to the total weight of the composition.

[0027] For example, an LNP-type cosmetic composition may be provided, further comprising ferulic acid and ascorbyl palmitate.

[0028] For example, an LNP-type cosmetic composition may be provided that additionally includes ectoin.

[0029] For example, an LNP-type cosmetic composition may be provided in which the content of the ectoin is 0.1 to 3.0 weight% relative to the total weight of the composition.

[0030] For example, an LNP-type cosmetic composition may be provided that further comprises hydroxyectoin.

[0031] For example, an LNP-type cosmetic composition may be provided in which the content of the hydroxyectoin is 0.1 to 2.0 weight% relative to the total weight of the composition.

[0032] For example, it additionally includes fullerenol, said fullerenol is C 60 (OH) n An LNP-type cosmetic composition may be provided having a structure in which n is an integer from 20 to 30.

[0033] For example, an LNP-type cosmetic composition may be provided in which the content of the fullerenol is 0.001 to 0.05 weight% relative to the total weight of the composition.

[0034] For example, an LNP-type cosmetic composition may be provided, further comprising ferulic acid, ascorbyl palmitate, ectoin, and fullerenol.

[0035] According to another aspect of the present invention, a method for preparing an LNP-type cosmetic composition may be provided, comprising: an oil phase preparation step of preparing an oil phase by mixing lecithin, cholesterol, lauric acid, tocopherol, and retinal; a water phase preparation step of preparing a water phase by mixing purified water, isopentyldiol, 1,2-hexanediol, glycerin, and sucrose; an LNP formation step of mixing and homogenizing the oil phase and the water phase to form an LNP; and an additive blending step of adding polyglyceryl-10 oleate, polysorbate 20, polysorbate 80, and ethylhexylglycerin.

[0036] For example, a method for preparing an LNP-type cosmetic composition may be provided, wherein in the above oil phase preparation step, the content of the retinal is 0.5 to 5.0 weight% relative to the total weight of the composition.

[0037] For example, a method for preparing an LNP-type cosmetic composition may be provided, wherein in the above oil phase preparation step, the weight ratio of the lecithin, the cholesterol, and the lauric acid is 1.0 : 0.1 to 0.4 : 0.1 to 0.4.

[0038] For example, a method for manufacturing an LNP-type cosmetic composition may be provided, wherein the LNP forming step comprises: an ultrasonic treatment step of applying ultrasound to a mixture of the oil phase and the aqueous phase; and a high-pressure homogenization step of performing high-pressure homogenization on the mixture that has undergone the ultrasonic treatment step.

[0039] For example, a method for manufacturing an LNP-type cosmetic composition may be provided, wherein in the ultrasonic treatment step, the frequency of the ultrasound is 15 to 50 kHz and the treatment time is 3 to 20 minutes.

[0040] For example, a method for manufacturing an LNP-type cosmetic composition may be provided, wherein in the high-pressure homogenization step, the homogenization pressure is 500 to 1,500 bar and the number of homogenization cycles is 1 to 7 times.

[0041] For example, a method for preparing an LNP-type cosmetic composition may be provided, wherein ferulic acid and ascorbyl palmitate are additionally mixed in the above oil phase preparation step.

[0042] For example, a method for preparing an LNP-type cosmetic composition may be provided, wherein ectoin and hydroxyectoin are additionally mixed in the above-mentioned aqueous preparation step.

[0043] For example, in the above oil phase manufacturing step, fullerenol is additionally mixed, and said fullerenol is C 60 (OH) n A method for manufacturing an LNP-type cosmetic composition having a structure, wherein n is an integer from 20 to 30, may be provided. Effects of the invention

[0044] The LNP-type cosmetic composition according to the present invention contains a high concentration of retinal while maintaining the stability of retinal during long-term storage.

[0045] The LNP-type cosmetic composition according to the present invention can improve the photostability and oxidative stability of retinal through a combination of an LNP double-membrane lipid composition, an antioxidant, and a high-content diol-based aqueous composition.

[0046] The LNP-type cosmetic composition according to the present invention has a structure in which retinal is encapsulated in LNP, so skin irritation can be alleviated despite the use of high concentrations of retinal.

[0047] The LNP-type cosmetic composition according to the present invention can ensure long-term stability of the formulation by improving LNP dispersion stability through a combination of three types of surfactants.

[0048] The LNP-type cosmetic composition according to the present invention can improve the skin penetration and delivery efficiency of retinal through the LNP structure.

[0049] The LNP-type cosmetic composition according to the present invention may further improve the stability of retinal by additionally including one or more of ferulic acid, ascorbyl palmitate, ectoin, hydroxyectoin, and fullerenol.

[0050] The method for manufacturing an LNP-type cosmetic composition according to the present invention can uniformly control the LNP particle size and improve retinal capture efficiency through a two-step homogenization process including ultrasonic treatment and high-pressure homogenization. Brief explanation of the drawing

[0051] FIG. 1 is a flowchart showing a method for preparing an LNP-type cosmetic composition according to one embodiment of the present invention. Figure 2 is a DLS analysis report measuring the particle size distribution and autocorrelation function (ACF) of an LNP-type cosmetic composition prepared according to Example 1 of the present invention. Specific details for implementing the invention

[0052] In one aspect of the present invention, an LNP-type cosmetic composition may comprise retinal, a lipid membrane composition, tocopherol, a surfactant composition, an aqueous composition, and ethylhexylglycerin, and the retinal may be captured in an LNP formed by the lipid membrane composition.

[0053] In one aspect of the present invention, the retinal may be a vitamin A-based retinoid also referred to as retinalaldehyde. The retinal is converted into retinoic acid in vivo and may be involved in promoting cell turnover, improving wrinkles and elasticity, and alleviating pigmentation. Since the conversion rate of the retinal to retinoic acid is faster than that of retinol, it may have high biological activity on the skin. Since the retinal has a conjugated double bond structure within its molecule, it may decompose, discolor, and experience a decrease in potency when exposed to light, heat, and oxygen. When used at high concentrations, the retinal may cause skin irritation such as erythema and stinging. In the present invention, the retinal can be protected from the external environment and skin irritation can be alleviated by encapsulating it in LNP.

[0054] In one embodiment, the lipid membrane composition may include lecithin, cholesterol, and lauric acid. The lecithin is a phospholipid with phosphatidylcholine as its main component and can form a double membrane structure by self-assembly in an aqueous environment. The double membrane structure constitutes the basic framework of the LNP and can encapsulate fat-soluble active ingredients such as retinal. The cholesterol is a sterol compound that can be inserted between the phospholipid molecules of the double membrane to control the fluidity of the membrane. The cholesterol can improve the mechanical strength and durability of the double membrane and provide structural stability to the LNP by suppressing phase transitions due to temperature changes. The lauric acid is a saturated fatty acid with 12 carbon atoms that can control the packing density of the double membrane. The lauric acid can influence the skin delivery efficiency of retinal by controlling the fluidity and permeability of the double membrane.

[0055] For example, the lecithin, cholesterol, and lauric acid may be combined in a weight ratio of 1.0:0.2:0.2.

[0056] In one embodiment, the tocopherol may be a fat-soluble antioxidant of the vitamin E family. The tocopherol can terminate a chain oxidation reaction by donating hydrogen to lipid peroxide radicals through phenolic hydroxyl groups. The tocopherol can inhibit the oxidation of the unsaturated fatty acids of the lipid membrane composition and the conjugated double bonds of the retinal. The tocopherol can be distributed within the double membrane of the LNP to prevent oxidative damage to the membrane components.

[0057] In one embodiment, the surfactant composition may include polyglyceryl-10 oleate, polysorbate 20, and polysorbate 80. The polyglyceryl-10 oleate may be a nonionic surfactant as an ester of polyglycerin and oleic acid. The polyglyceryl-10 oleate may be suitable for stabilizing oil-in-water type emulsions, having an HLB value in the range of about 14 to 16. The polysorbate 20 may be a polyoxyethylene derivative of sorbitan monolaurate, having an HLB value in the range of about 16 to 17. The polysorbate 80 may be a polyoxyethylene derivative of sorbitan monooleate, having an HLB value in the range of about 15. Since the three types of surfactants have different HLB values ​​and molecular structures, when used in combination, they are arranged complementarily at the oil-water interface to lower the interfacial energy. The above surfactant composition can be adsorbed onto the surface of the LNP particles to prevent aggregation and bonding between particles.

[0058] For example, the polyglyceryl-10 oleate, the polysorbate 20, and the polysorbate 80 can be combined in equal weight ratios.

[0059] In one embodiment, the aqueous composition may include purified water, isopentyldiol, 1,2-hexanediol, glycerin, and sucrose. The purified water may be a base constituting the continuous phase of the aqueous phase. The isopentyldiol is a branched diol with 5 carbon atoms and may have a moisturizing effect and an antibacterial auxiliary effect. The isopentyldiol has low skin irritation and a light feel, and may have little stickiness even when formulated at a high concentration. The 1,2-hexanediol is a straight-chain diol with 6 carbon atoms and may have a moisturizing effect, an antibacterial auxiliary effect, and a solvent function. When formulated in high amounts, the isopentyldiol and the 1,2-hexanediol may contribute to maintaining the osmotic pressure balance inside and outside the LNP. The glycerin is a triol with 3 carbon atoms and may contribute to skin moisturization due to its high hygroscopicity. The above sucrose is a disaccharide and can function as a osmotic pressure regulator and a cryoprotectant during the freeze-drying of the above LNP. The above sucrose can stabilize the membrane structure by forming hydrogen bonds with the phospholipid head groups of the above LNP double membrane.

[0060] For example, the isopentyldiol may be blended at 20% by weight relative to the total weight of the composition, and the 1,2-hexanediol may be blended at 10% by weight, resulting in a total diol content of 30% by weight. The glycerin and the sucrose may each be blended at 10% by weight.

[0061] In one embodiment, the ethylhexylglycerin may be an ethylhexyl ether derivative of glycerin. The ethylhexylglycerin may assist the preservation effect of the composition through a bacteriostatic action. The ethylhexylglycerin has a skin conditioning effect and may contribute to alleviating skin irritation caused by the retinal.

[0062] In one embodiment, the LNP may be a closed vesicle formed by self-assembling a double membrane composed of the lecithin, cholesterol, and lauric acid in an aqueous medium. The LNP may be in the form of a single-layer vesicle or a multilayer vesicle. The retinal may be captured within the double membrane of the LNP or in a hydrophobic core. The retinal captured in the LNP may be shielded from light, heat, and oxygen of the external environment, thereby improving stability. Since the LNP is similar to the lipid structure of the stratum corneum of the skin, it has high skin affinity and can promote transdermal absorption of the retinal.

[0063] In one aspect of the present invention, the content of the retinal may be 0.5 to 5.0 weight% relative to the total weight of the composition. If the content of the retinal is less than 0.5 weight%, the physiological activity effect on the skin may not be sufficient. If the content of the retinal exceeds 5.0 weight%, skin irritation may increase and it may be difficult to ensure stability within the composition.

[0064] In one embodiment, the content of the retinal may be 0.8 to 1.5 weight percent relative to the total weight of the composition.

[0065] For example, the content of the retinal may be 1.0% by weight relative to the total weight of the composition. The 1.0% by weight retinal content may be set considering the balance of physiological activity and stability for the skin.

[0066] In one aspect of the present invention, the weight ratio of the lecithin, the cholesterol, and the lauric acid may be 1.0 : 0.1 to 0.4 : 0.1 to 0.4. The weight ratio may affect the structural stability, fluidity, and permeability of the LNP double membrane.

[0067] In one embodiment, if the ratio of cholesterol is less than 0.1, the mechanical strength of the double membrane may not be sufficient. If the ratio of cholesterol exceeds 0.4, the fluidity of the double membrane may be excessively reduced, which may decrease the release efficiency of the retinal. If the ratio of lauric acid is less than 0.1, the permeability control effect of the double membrane may not be sufficient. If the ratio of lauric acid exceeds 0.4, the packing density of the double membrane may become excessively loose, which may reduce LNP stability.

[0068] For example, the weight ratio of the lecithin, cholesterol, and lauric acid may be 1.0 : 0.2 : 0.2.

[0069] In one aspect of the present invention, the polyglyceryl-10 oleate, the polysorbate 20, and the polysorbate 80 may each be included in an amount of 1.0 to 3.0 weight% relative to the total weight of the composition. If the content of each of the surfactants is less than 1.0 weight%, the LNP dispersion stabilization effect may not be sufficient. If the content of each of the surfactants exceeds 3.0 weight%, skin irritation may increase or the viscosity of the formulation may change excessively.

[0070] In one embodiment, the three types of surfactants are blended in equal amounts, so that the total surfactant content is 3.0 to 9.0 weight% relative to the total weight of the composition.

[0071] For example, the polyglyceryl-10 oleate, the polysorbate 20, and the polysorbate 80 may each be blended at 2.0% by weight relative to the total weight of the composition to have a total surfactant content of 6.0% by weight.

[0072] In one aspect of the present invention, the isopentyldiol may be included in an amount of 15 to 25 weight% relative to the total weight of the composition, and the 1,2-hexanediol may be included in an amount of 5 to 15 weight% relative to the total weight of the composition. The diol-based components may contribute to moisturizing effects, maintaining osmotic pressure balance, and controlling the viscosity of the composition.

[0073] In one embodiment, if the content of the isopentyldiol is less than 15% by weight, the effect of maintaining osmotic pressure balance may not be sufficient. If the content of the isopentyldiol exceeds 25% by weight, the usability of the composition may be reduced. If the content of the 1,2-hexanediol is less than 5% by weight, the moisturizing and antibacterial auxiliary effects may not be sufficient. If the content of the 1,2-hexanediol exceeds 15% by weight, skin irritation may increase.

[0074] For example, the isopentyldiol may be formulated at 20% by weight relative to the total weight of the composition, and the 1,2-hexanediol may be formulated at 10% by weight.

[0075] In one aspect of the present invention, the content of the tocopherol may be 0.3 to 1.0 weight% relative to the total weight of the composition. If the content of the tocopherol is less than 0.3 weight%, the antioxidant effect on the retinal and the lipid membrane composition may not be sufficient. If the content of the tocopherol exceeds 1.0 weight%, it may affect the color or scent of the composition.

[0076] In one embodiment, the content of the tocopherol may be 0.4 to 0.7 weight% relative to the total weight of the composition.

[0077] For example, the content of the tocopherol may be 0.5% by weight relative to the total weight of the composition.

[0078] In one aspect of the present invention, the glycerin may be included in an amount of 5 to 15 weight percent based on the total weight of the composition, and the sucrose may be included in an amount of 5 to 15 weight percent based on the total weight of the composition. The glycerin and the sucrose may perform moisturizing and osmotic pressure regulating functions in the aqueous composition.

[0079] In one embodiment, if the content of glycerin is less than 5% by weight, the skin moisturizing effect may not be sufficient. If the content of glycerin exceeds 15% by weight, the stickiness of the composition may increase. If the content of sucrose is less than 5% by weight, the LNP film stabilization effect may not be sufficient. If the content of sucrose exceeds 15% by weight, the viscosity of the composition may increase excessively.

[0080] For example, the glycerin may be blended at 10% by weight relative to the total weight of the composition, and the sucrose may be blended at 10% by weight.

[0081] In one aspect of the present invention, the content of ethylhexylglycerin may be 0.3 to 1.0 weight% relative to the total weight of the composition. If the content of ethylhexylglycerin is less than 0.3 weight%, the preservative aid effect may not be sufficient. If the content of ethylhexylglycerin exceeds 1.0 weight%, skin irritation may occur.

[0082] In one embodiment, the content of the ethylhexylglycerin may be 0.4 to 0.7 weight% relative to the total weight of the composition.

[0083] For example, the content of the ethylhexylglycerin may be 0.5% by weight relative to the total weight of the composition.

[0084] In one aspect of the present invention, the average particle size of the LNP may be 50 to 300 nm. If the average particle size of the LNP is less than 50 nm, the capture efficiency of the retinal may be reduced. If the average particle size of the LNP exceeds 300 nm, the skin penetration efficiency may be reduced and the appearance stability of the formulation may be reduced.

[0085] In one embodiment, the average particle size of the LNP may be 80 to 200 nm. The particle size within this range may be suitable for balancing the capture efficiency and skin penetration efficiency of the retinal.

[0086] For example, the average particle size of the LNP may be 100 to 150 nm. The average particle size may be measured by dynamic light scattering or laser diffraction.

[0087] In one aspect of the present invention, the LNP-type cosmetic composition may further comprise ferulic acid. The ferulic acid may be a phenolic compound having the chemical name 4-hydroxy-3-methoxycinnamic acid. The ferulic acid has ultraviolet absorption properties and may contribute to inhibiting the photodegradation of the retinal.

[0088] In one embodiment, the ferulic acid may exhibit radical scavenging activity through phenolic hydroxyl groups. The ferulic acid may form an antioxidant network when combined with the tocopherol. The ferulic acid may regenerate the antioxidant activity of the tocopherol by reducing the tocopherol radicals generated after the tocopherol donates hydrogen to radicals.

[0089] For example, the ferulic acid can absorb ultraviolet light in the UVA region, with a maximum absorption wavelength in the range of about 320 to 330 nm. The ultraviolet absorption characteristic can contribute to inhibiting the isomerization or decomposition of the conjugated double bond of the retinal by ultraviolet light.

[0090] In one aspect of the present invention, the content of the ferulic acid may be 0.1 to 1.0 weight% relative to the total weight of the composition. If the content of the ferulic acid is less than 0.1 weight%, the ultraviolet absorption and antioxidant effects may not be sufficient. If the content of the ferulic acid exceeds 1.0 weight%, a change in color or solubility problems may occur in the composition.

[0091] In one embodiment, the content of the ferulic acid may be 0.2 to 0.7 weight% relative to the total weight of the composition.

[0092] For example, the content of the ferulic acid may be 0.3 to 0.5 weight percent relative to the total weight of the composition.

[0093] In one aspect of the present invention, the LNP-type cosmetic composition may further comprise ascorbyl palmitate. The ascorbyl palmitate may be a fat-soluble vitamin C derivative as an ester of ascorbic acid and palmitic acid. Since the ascorbyl palmitate is fat-soluble, it may be distributed within the double membrane of the LNP.

[0094] In one embodiment, the ascorbyl palmitate has reducing power and can reduce oxidized tocopherol to regenerate the antioxidant activity of the tocopherol. When the ascorbyl palmitate is used in combination with the ferulic acid and the tocopherol, it can form an antioxidant regeneration cycle.

[0095] For example, when the above ascorbyl palmitate, the above tocopherol, and the above ferulic acid are used in combination, a chain regeneration mechanism may be formed in which the tocopherol neutralizes radicals, the ferulic acid regenerates the tocopherol, and the ascorbyl palmitate reduces the oxidized ferulic acid.

[0096] In one aspect of the present invention, the content of ascorbyl palmitate may be 0.1 to 1.0 weight% relative to the total weight of the composition. If the content of ascorbyl palmitate is less than 0.1 weight%, the antioxidant regenerative effect may not be sufficient. If the content of ascorbyl palmitate exceeds 1.0 weight%, it may affect the stability of the composition.

[0097] In one embodiment, the content of the ascorbyl palmitate may be 0.2 to 0.7 weight% relative to the total weight of the composition.

[0098] For example, the content of the ascorbyl palmitate may be 0.3 to 0.5 weight percent relative to the total weight of the composition.

[0099] In one aspect of the present invention, the LNP-type cosmetic composition may further comprise ferulic acid and ascorbyl palmitate. The ferulic acid and the ascorbyl palmitate may form an antioxidant complex together with the tocopherol.

[0100] In one embodiment, the antioxidant complex composed of the tocopherol, the ferulic acid, and the ascorbyl palmitate can inhibit the oxidative degradation of the retinal and prevent lipid peroxidation of the LNP double membrane. The antioxidant complex can extend the duration of antioxidant activity compared to the use of the individual components alone.

[0101] For example, 0.5% by weight of the tocopherol, 0.3 to 0.5% by weight of the ferulic acid, and 0.3 to 0.5% by weight of the ascorbyl palmitate may be combined.

[0102] In one aspect of the present invention, the LNP-type cosmetic composition may further comprise ectoin. The ectoin may be a cyclic amino acid derivative with the chemical name 1,4,5,6-tetrahydro-2-methyl-4-pyrimidinecarboxylic acid. The ectoin may be a natural osmotic protective substance derived from the halophilic microorganism *Halomonas elongata*.

[0103] In one embodiment, the ectoin has the ability to form a hydration layer and can form a hydration shell around it by strongly binding to water molecules. The hydration layer is formed around the aldehyde group of the retinal and can inhibit hydrolysis reactions. The ectoin can contribute to maintaining the structural stability of the LNP by buffering osmotic stress in a high-content diol environment.

[0104] For example, the above ectoin is a compatible solute that microorganisms biosynthesize to survive in extreme environments and can have the function of protecting proteins and lipid membranes from environmental stress. This function can be applied to the stabilization of the retinal and the LNP structure in the above LNP-type cosmetic composition.

[0105] In one aspect of the present invention, the content of ectoin may be 0.1 to 3.0 weight% relative to the total weight of the composition. If the content of ectoin is less than 0.1 weight%, the formation of a hydration layer and the osmotic stress buffering effect may not be sufficient. If the content of ectoin exceeds 3.0 weight%, the cost of the composition increases and further improvement of effects may be limited.

[0106] In one embodiment, the content of ectoin may be 0.3 to 2.0 weight% relative to the total weight of the composition.

[0107] For example, the content of the ectoin may be 0.5 to 1.5 weight percent relative to the total weight of the composition.

[0108] In one aspect of the present invention, the LNP-type cosmetic composition may additionally include hydroxyectoin together with the ectoin. The hydroxyectoin may be a derivative in which a hydroxyl group is introduced at the 5-position of the ectoin. The chemical name of the hydroxyectoin may be 5-hydroxy-1,4,5,6-tetrahydro-2-methyl-4-pyrimidinecarboxylic acid.

[0109] In one embodiment, the hydroxyectoin may have higher thermal stability than the ectoin. The hydroxyectoin may have increased hydrogen bond formation ability through additional hydroxyl groups, thereby increasing the density of the hydration layer. The combined use of the ectoin and the hydroxyectoin can improve the stability and persistence of the hydration layer.

[0110] For example, the ectoin and the hydroxyectoin may be combined in a weight ratio of 1:0.3 to 1:1.

[0111] In one aspect of the present invention, the content of the hydroxyectoin may be 0.1 to 2.0 weight% relative to the total weight of the composition. If the content of the hydroxyectoin is less than 0.1 weight%, the combined effect with the ectoin may not be sufficient. If the content of the hydroxyectoin exceeds 2.0 weight%, further improvement in effect may be limited.

[0112] In one embodiment, the content of the hydroxyectoin may be 0.2 to 1.0 weight% relative to the total weight of the composition.

[0113] For example, the content of the hydroxyectoin may be 0.3 to 0.7 weight% relative to the total weight of the composition.

[0114] In one aspect of the present invention, the LNP-type cosmetic composition may further comprise fullerenol. The fullerenol is a hydroxyl derivative of fullerene, C 60 It may be a compound in which multiple hydroxyl groups are bonded to the carbon cage structure of. The fullerenol is C 60 C with n hydroxyl groups attached 60 (OH) n It has a structure, and the above n can be an integer from 20 to 30.

[0115] In one embodiment, the fullerenol has a spherical carbon structure containing a plurality of conjugated double bonds, so it may have a high radical scavenging ability. Since the fullerenol can simultaneously neutralize a plurality of radicals per molecule, it may have a higher radical neutralization efficiency compared to general antioxidants. The fullerenol can inhibit the oxidative decomposition of the retinal by scavenging peroxide radicals generated around the conjugated double bonds of the retinal.

[0116] For example, the fullerenol can be dissolved in the aqueous phase by being made water-soluble through hydroxyl groups. The fullerenol can be distributed on the double membrane surface of the LNP or in the aqueous phase to neutralize reactive oxygen species introduced from outside the LNP.

[0117] In one aspect of the present invention, the content of the fullerenol may be 0.001 to 0.05 weight% relative to the total weight of the composition. Since the fullerenol has high radical scavenging efficiency, it can be effective even at a low content. If the content of the fullerenol is less than 0.001 weight%, the antioxidant effect may not be sufficient. If the content of the fullerenol exceeds 0.05 weight%, it may affect the color of the composition or the cost may increase excessively.

[0118] In one embodiment, the content of the fullerenol may be 0.003 to 0.03 weight% relative to the total weight of the composition.

[0119] For example, the content of the fullerenol may be 0.005 to 0.01 weight% relative to the total weight of the composition.

[0120] In one aspect of the present invention, the LNP-type cosmetic composition may further comprise ferulic acid, ascorbyl palmitate, ectoin, and fullerenol. These components may form a multi-stabilization system together with the tocopherol.

[0121] In one embodiment, the tocopherol, the ferulic acid, and the ascorbyl palmitate form an antioxidant regeneration cycle, and the fullerenol can enhance the antioxidant effect through polyvalent radical scavenging. The ectoin can inhibit the hydrolysis of the retinal and buffer osmotic stress by forming a hydration layer.

[0122] For example, 0.5% by weight of the tocopherol, 0.3 to 0.5% by weight of the ferulic acid, 0.3 to 0.5% by weight of the ascorbyl palmitate, 0.5 to 1.5% by weight of the ectoin, and 0.005 to 0.01% by weight of the fullerenol may be combined.

[0123] Description of Fig. 1

[0124] FIG. 1 may be a flowchart illustrating a method for manufacturing an LNP-type cosmetic composition according to an embodiment of the present invention. Referring to FIG. 1, the manufacturing method may include an oil phase manufacturing step, a water phase manufacturing step, an LNP formation step, and an additive blending step. The oil phase manufacturing step and the water phase manufacturing step may be performed sequentially or in parallel. The LNP formation step may include a process of mixing and homogenizing the oil phase and the water phase. The additive blending step may be performed after the LNP formation step.

[0125] In one aspect of the present invention, a method for preparing an LNP-type cosmetic composition may include an oil phase preparation step, a water phase preparation step, an LNP formation step, and an additive blending step. Each step of the preparation method may refer to the flowchart illustrated in FIG. 1.

[0126] In one embodiment, the oil phase preparation step may be a step of preparing an oil phase by mixing lecithin, cholesterol, lauric acid, tocopherol, and retinal. In the oil phase preparation step, the lipid membrane composition components may be heated and melted at a temperature of 40 to 70°C. The retinal may be added and mixed after the lipid membrane composition components are melted. The oil phase preparation step may be performed under light-blocking conditions.

[0127] In one embodiment, the aqueous phase preparation step may be a step of preparing an aqueous phase by mixing purified water, isopentyldiol, 1,2-hexanediol, glycerin, and sucrose. In the aqueous phase preparation step, the sucrose may be dissolved under heating. The aqueous phase may be controlled to a temperature similar to that of the oil phase before being mixed with the oil phase.

[0128] In one embodiment, the LNP forming step may be a step of forming an LNP by mixing and homogenizing the oil phase and the aqueous phase. In the LNP forming step, the oil phase may be stirred while being slowly added to the aqueous phase. The homogenization may be performed using a homogenizer, an ultrasonic device, or a high-pressure homogenizer.

[0129] In one embodiment, the additive blending step may be a step of adding polyglyceryl-10 oleate, polysorbate 20, polysorbate 80, and ethylhexylglycerin. The additive blending step may be performed after the LNP dispersion formed in the LNP formation step has been cooled to room temperature. The surfactant composition may impart dispersion stability to the LNP particles.

[0130] For example, the oil phase manufacturing step may be performed at 50 to 60°C, the aqueous phase manufacturing step may be performed at 50 to 60°C, the LNP forming step may be performed at 45 to 55°C, and the additive blending step may be performed at 25 to 35°C.

[0131] In one aspect of the present invention, the content of the retinal in the oil phase manufacturing step may be 0.5 to 5.0 weight% relative to the total weight of the composition.

[0132] In one embodiment, the content of the retinal may be 0.8 to 1.5 weight percent relative to the total weight of the composition.

[0133] For example, the content of the retinal may be 1.0% by weight relative to the total weight of the composition.

[0134] In one aspect of the present invention, in the oil phase manufacturing step, the weight ratio of the lecithin, the cholesterol, and the lauric acid may be 1.0 : 0.1 to 0.4 : 0.1 to 0.4.

[0135] In one embodiment, the weight ratio may affect the structural characteristics of the LNP double membrane.

[0136] For example, the weight ratio of the lecithin, cholesterol, and lauric acid may be 1.0 : 0.2 : 0.2.

[0137] In one aspect of the present invention, the LNP forming step may include an ultrasonic treatment step and a high-pressure homogenization step. The two-step homogenization process may contribute to uniformly controlling the particle size of the LNP and improving the capture efficiency of the retinal.

[0138] In one embodiment, the ultrasonic treatment step may be a step of applying ultrasound to the mixture of the oil phase and the water phase. In the ultrasonic treatment step, the ultrasonic energy may induce cavitation in the mixture to induce the micronization of droplets and the initial formation of LNPs. The high-pressure homogenization step may be a step of performing high-pressure homogenization on the mixture that has undergone the ultrasonic treatment step. In the high-pressure homogenization step, the shear force and collision energy caused by the high pressure may further reduce and homogenize the particle size of the LNPs.

[0139] For example, after the ultrasonic treatment step, the average particle size of the LNP may be 200 to 500 nm, and after the high-pressure homogenization step, the average particle size of the LNP may be reduced to 50 to 150 nm.

[0140] In one aspect of the present invention, in the ultrasonic treatment step, the frequency of the ultrasound may be 15 to 50 kHz, and the treatment time may be 3 to 20 minutes. If the frequency is less than 15 kHz, the cavitation effect may not be sufficient. If the frequency exceeds 50 kHz, the cavitation intensity may decrease, and the micronization efficiency may be reduced. If the treatment time is less than 3 minutes, homogenization may not be sufficient. If the treatment time exceeds 20 minutes, decomposition of the retinal may occur due to excessive energy input.

[0141] In one embodiment, the frequency of the ultrasound may be 20 to 40 kHz, and the processing time may be 5 to 15 minutes.

[0142] For example, the frequency of the ultrasound may be 25 to 35 kHz, and the processing time may be 8 to 12 minutes.

[0143] In one aspect of the present invention, in the high-pressure homogenization step, the homogenization pressure may be 500 to 1,500 bar, and the number of homogenization cycles may be 1 to 7. If the homogenization pressure is less than 500 bar, the particle size reduction effect may not be sufficient. If the homogenization pressure exceeds 1,500 bar, the LNP structure may be destroyed due to excessive shear force. If the number of homogenization cycles is less than 1, homogenization is not performed, and the particle size distribution may be non-uniform; if the number of homogenization cycles is less than 2, the particle size distribution may still be non-uniform. If the number of homogenization cycles exceeds 7, the additional particle size reduction effect is limited and process efficiency may decrease.

[0144] In one embodiment, the homogenization pressure may be 800 to 1,200 bar, and the number of homogenization cycles may be 3 to 5 times.

[0145] For example, the homogenization pressure may be 900 to 1,100 bar, and the number of homogenization cycles may be 3 to 4 times.

[0146] In one aspect of the present invention, ferulic acid and ascorbyl palmitate may be additionally mixed in the oil phase preparation step. Since the ferulic acid and ascorbyl palmitate have fat-soluble properties, they can be dissolved in the oil phase.

[0147] In one embodiment, the ferulic acid and the ascorbyl palmitate may be combined with the tocopherol in the oil phase to form an antioxidant complex. The antioxidant complex may inhibit the oxidation of the retinal in the oil phase.

[0148] For example, 0.3 to 0.5 weight% of the ferulic acid and 0.3 to 0.5 weight% of the ascorbyl palmitate may be mixed in the oil phase preparation step.

[0149] In one aspect of the present invention, ectoin and hydroxyectoin may be further mixed in the aqueous phase preparation step. Since the ectoin and hydroxyectoin have water-soluble properties, they can be dissolved in the aqueous phase.

[0150] In one embodiment, the ectoin and the hydroxyectoin form a hydration layer in the aqueous phase to provide a hydration shell on the surface of the LNP even after the LNP formation step.

[0151] For example, 0.5 to 1.5 weight% of the ectoin and 0.3 to 0.7 weight% of the hydroxyectoin may be mixed in the aqueous phase preparation step.

[0152] In one aspect of the present invention, fullerenol may be additionally mixed in the oil phase manufacturing step. The fullerenol is C 60 C with n hydroxyl groups attached 60 (OH) n It has a structure, and the above n can be an integer from 20 to 30.

[0153] In one embodiment, the fullerenol may be dispersed in the oil phase or the aqueous phase. Since the fullerenol has a plurality of hydroxyl groups, it may exhibit water solubility, but when dispersed in the oil phase, it may be distributed adjacent to the double membrane of the LNP.

[0154] For example, 0.005 to 0.01 weight percent of the fullerenol may be mixed in the oil phase preparation step. The fullerenol may be added and dispersed after the other components of the oil phase have been dissolved.

[0155] The present invention will be explained in more detail below using examples. However, the following examples are intended only to explain the structure and effects of the present invention and are not intended to limit the scope of the invention.

[0156] Examples 1 to 4

[0157] LNP-type cosmetic compositions were prepared by varying the content of retinal. Example 1 used 0.5 wt% retinal, Example 2 used 1.0 wt% retinal, Example 3 used 1.5 wt% retinal, and Example 4 used 2.0 wt% retinal.

[0158] In the oil phase preparation step, 1.0 wt% lecithin, 0.2 wt% cholesterol, 0.2 wt% lauric acid, and 0.5 wt% tocopherol were heated and dissolved at 55°C. After the lipid membrane components were completely dissolved, retinal in an amount corresponding to each example was added and uniformly mixed under light-shielding conditions to prepare the oil phase.

[0159] In the aqueous phase preparation step, purified water, 20.0 wt% isopentyldiol, 10.0 wt% 1,2-hexanediol, 10.0 wt% glycerin, and 10.0 wt% sucrose were mixed while heating at 55°C to prepare the aqueous phase. The content of purified water was adjusted according to the retinal content to 41.1 wt% for Example 1, 40.6 wt% for Example 2, 40.1 wt% for Example 3, and 39.6 wt% for Example 4, so that the total sum was 100 wt%.

[0160] In the LNP formation step, the oil phase was slowly added to the aqueous phase while homogenizing with a homomixer at 8,000 rpm for 10 minutes to form the LNP.

[0161] In the additive formulation step, the LNP dispersion was cooled to 35°C or lower, and then 2.0% by weight of polyglyceryl-10 oleate, 2.0% by weight of polysorbate 20, 2.0% by weight of polysorbate 80, and 0.5% by weight of ethylhexylglycerin were added and uniformly mixed to complete the LNP-type cosmetic composition.

[0162] Referring to Figure 2, the peaks appear singly in almost the same region in the intensity distribution as well as the volume and number distributions, which proves that a very clean LNP was formed with almost no large particles or fine impurities present in the formulation. In addition, the fact that the Fitting Curve (ACF) in Figure 2 exhibits a smooth decay shape without noise suggests that the concentration of the sample was appropriate during measurement and that the Brownian motion of the particles was very stable.

[0163] Examples 5 to 7

[0164] LNP-type cosmetic compositions were prepared by varying the content of three types of surfactants. In Example 5, polyglyceryl-10 oleate, polysorbate 20, and polysorbate 80 were each used at 1.0 wt%, in Example 6 at 2.0 wt%, and in Example 7 at 3.0 wt%.

[0165] The oil phase manufacturing step and the water phase manufacturing step were performed in the same manner as in Example 2. 1.0 wt% of retinal was used.

[0166] The LNP formation step was performed in the same manner as in Example 2.

[0167] In the additive formulation step, the LNP dispersion was cooled to 35°C or lower, and then polyglyceryl-10 oleate, polysorbate 20, and polysorbate 80 were added in amounts corresponding to each example. Ethylhexylglycerin was added at 0.5% by weight. The content of purified water was adjusted according to the total amount of surfactant to 43.6% by weight for Example 5, 40.6% by weight for Example 6, and 37.6% by weight for Example 7, so that the total sum was 100% by weight.

[0168] Examples 8 to 10

[0169] LNP-type cosmetic compositions were prepared by varying the content of isopentyldiol and 1,2-hexanediol. Example 8 used 15.0 wt% isopentyldiol and 5.0 wt% 1,2-hexanediol, Example 9 used 20.0 wt% isopentyldiol and 10.0 wt% 1,2-hexanediol, and Example 10 used 25.0 wt% isopentyldiol and 15.0 wt% 1,2-hexanediol.

[0170] The oil phase manufacturing step was performed in the same manner as in Example 2. 1.0 wt% of retinal was used.

[0171] In the aqueous phase preparation step, purified water, isopentyldiol and 1,2-hexanediol in amounts corresponding to each example, 10.0 wt% glycerin, and 10.0 wt% sucrose were mixed while heating at 55°C to prepare the aqueous phase. The content of purified water was adjusted according to the total amount of diol to 50.6 wt% for Example 8, 40.6 wt% for Example 9, and 30.6 wt% for Example 10.

[0172] The LNP formation step and the additive blending step were performed in the same manner as in Example 2.

[0173] Examples 11 to 13

[0174] LNP-type cosmetic compositions were prepared by varying the content of ferulic acid. Example 11 used 0.1 wt% ferulic acid, Example 12 used 0.5 wt% ferulic acid, and Example 13 used 1.0 wt% ferulic acid.

[0175] In the oil phase preparation step, ferulic acid in an amount corresponding to each example was additionally added to the oil phase composition of Example 2. The oil phase was prepared by heating and dissolving ferulic acid at 55°C together with 1.0 wt% lecithin, 0.2 wt% cholesterol, 0.2 wt% lauric acid, 0.5 wt% tocopherol, and 1.0 wt% retinal.

[0176] In the aqueous phase preparation step, the content of purified water was adjusted according to the ferulic acid content to 40.5 wt% for Example 11, 40.1 wt% for Example 12, and 39.6 wt% for Example 13. The other aqueous phase composition was the same as in Example 2, using 20.0 wt% isopentyldiol, 10.0 wt% 1,2-hexanediol, 10.0 wt% glycerin, and 10.0 wt% sucrose.

[0177] The LNP formation step and the additive blending step were performed in the same manner as in Example 2.

[0178] Examples 14 to 16

[0179] LNP-type cosmetic compositions were prepared by varying the content of ectoin. Example 14 used 0.5 wt% ectoin, Example 15 used 1.0 wt% ectoin, and Example 16 used 2.0 wt% ectoin.

[0180] The oil phase manufacturing step was performed in the same manner as in Example 2.

[0181] In the aqueous phase preparation step, ectoin in an amount corresponding to each example was additionally added to the aqueous phase composition of Example 2. A aqueous phase was prepared by mixing purified water, 20.0 wt% isopentyldiol, 10.0 wt% 1,2-hexanediol, 10.0 wt% glycerin, 10.0 wt% sucrose, and ectoin while heating at 55°C. The content of purified water was adjusted according to the ectoin content to 40.1 wt% for Example 14, 39.6 wt% for Example 15, and 38.6 wt% for Example 16.

[0182] The LNP formation step and the additive blending step were performed in the same manner as in Example 2.

[0183] Example 17

[0184] An LNP-type cosmetic composition was prepared by using ectoin and hydroxyectoin in combination. 1.0 wt% of ectoin and 0.5 wt% of hydroxyectoin were used.

[0185] The oil phase manufacturing step was performed in the same manner as in Example 2.

[0186] In the aqueous phase preparation step, 1.0 wt% of ectoin and 0.5 wt% of hydroxyectoin were additionally added to the aqueous phase composition of Example 2. An aqueous phase was prepared by mixing 39.1 wt% of purified water, 20.0 wt% of isopentyldiol, 10.0 wt% of 1,2-hexanediol, 10.0 wt% of glycerin, 10.0 wt% of sucrose, 1.0 wt% of ectoin, and 0.5 wt% of hydroxyectoin while heating at 55°C.

[0187] The LNP formation step and the additive blending step were performed in the same manner as in Example 2.

[0188] Examples 18 to 20

[0190] LNP-type cosmetic compositions were prepared by varying the content of fullerenol. Example 18 used 0.001 wt% fullerenol, Example 19 used 0.005 wt% fullerenol, and Example 20 used 0.01 wt% fullerenol. The fullerenol is C 60 (OH) 24 It used one that has the structure of.

[0191] In the oil phase preparation step, fullerenol in an amount corresponding to each example was additionally added to the oil phase composition of Example 2. Lecithin 1.0 wt%, cholesterol 0.2 wt%, lauric acid 0.2 wt%, tocopherol 0.5 wt%, and retinal 1.0 wt% were heated and dissolved at 55°C, then fullerenol was added and uniformly dispersed to prepare the oil phase.

[0192] In the aqueous phase preparation step, the content of purified water was adjusted according to the fullerenol content to 40.599 wt% for Example 18, 40.595 wt% for Example 19, and 40.59 wt% for Example 20. The other aqueous phase compositions were the same as in Example 2.

[0193] The LNP formation step and the additive blending step were performed in the same manner as in Example 2.

[0194] Example 21

[0195] An LNP-type cosmetic composition containing ferulic acid, ascorbyl palmitate, ectoin, hydroxyectoin, and fullerenol was prepared.

[0196] In the oil phase preparation step, the oil phase was prepared by heating and melting 1.0 wt% lecithin, 0.2 wt% cholesterol, 0.2 wt% lauric acid, 0.5 wt% tocopherol, 1.0 wt% retinal, 0.4 wt% ferulic acid, 0.4 wt% ascorbyl palmitate, and 0.005 wt% fullerenol at 55°C. The fullerenol is C 60 (OH) 24 It used one that has the structure of.

[0197] In the aqueous phase preparation step, 37.295 wt% of purified water, 20.0 wt% of isopentyldiol, 10.0 wt% of 1,2-hexanediol, 10.0 wt% of glycerin, 10.0 wt% of sucrose, 1.0 wt% of ectoin, and 0.5 wt% of hydroxyectoin were mixed while heating at 55°C to prepare the aqueous phase.

[0198] The LNP formation step and the additive blending step were performed in the same manner as in Example 2. 2.0 wt% of polyglyceryl-10 oleate, 2.0 wt% of polysorbate 20, 2.0 wt% of polysorbate 80, and 0.5 wt% of ethylhexylglycerin were added.

[0199] Example 22

[0200] An LNP-type cosmetic composition was prepared by applying a two-stage homogenization process. The oil phase preparation and water phase preparation stages were carried out using the same method and composition as in Example 2. In the LNP formation stage, the oil phase was slowly added to the water phase while performing ultrasonic treatment as a first step. The ultrasonic treatment was performed for 10 minutes at a frequency of 25 kHz. After ultrasonic treatment, high-pressure homogenization was performed as a second step using a high-pressure homogenizer. High-pressure homogenization was repeated three times at a pressure of 1,000 bar. The additive blending stage was carried out using the same method as in Example 2.

[0201] Example 23

[0202] An LNP-type cosmetic composition was prepared by applying a two-step homogenization process to a composition containing a multi-stabilization system. The oil phase preparation step and the water phase preparation step were performed using the same method and composition as in Example 21. The LNP formation step applied the same two-step homogenization process as in Example 22. While slowly adding the oil phase to the water phase, ultrasonic treatment was performed first at a frequency of 25 kHz for 10 minutes. After ultrasonic treatment, high-pressure homogenization was performed three times at a pressure of 1,000 bar as a second step. The additive blending step was performed using the same method as in Example 21.

[0203] Comparative Examples 1 and 2

[0204] An LNP-type cosmetic composition was prepared by setting the retinal content outside the range of the present invention. Comparative Example 1 used 0.3 wt% of retinal, and Comparative Example 2 used 5.5 wt% of retinal. The oil phase preparation step, water phase preparation step, LNP formation step, and additive blending step were performed in the same manner as in Example 2. The content of purified water was adjusted according to the retinal content to 41.3 wt% for Comparative Example 1 and 36.1 wt% for Comparative Example 2 so that the total sum was 100 wt%.

[0205] Comparative Example 3

[0206] An LNP-type cosmetic composition was prepared using a single surfactant instead of three types of surfactants. Polysorbate 80 at 6.0 wt% was used alone. The oil phase preparation step, the aqueous phase preparation step, and the LNP formation step were performed in the same manner as in Example 2. In the additive blending step, the LNP dispersion was cooled to 35°C or lower, then 6.0 wt% of polysorbate 80 and 0.5 wt% of ethylhexylglycerin were added and uniformly mixed. The content of purified water was set to 40.6 wt%, the same as in Example 2.

[0207] Comparative Example 4

[0208] An LNP-type cosmetic composition was prepared by setting the content of isopentyldiol and 1,2-hexanediol lower than the range of the present invention. 5.0 wt% of isopentyldiol and 3.0 wt% of 1,2-hexanediol were used. The oil phase preparation step was performed in the same manner as in Example 2. In the aqueous phase preparation step, 62.6 wt% of purified water, 5.0 wt% of isopentyldiol, 3.0 wt% of 1,2-hexanediol, 10.0 wt% of glycerin, and 10.0 wt% of sucrose were mixed while heating at 55°C to prepare the aqueous phase. The LNP formation step and the additive blending step were performed in the same manner as in Example 2.

[0209] Comparative Example 5

[0210] An emulsion-type cosmetic composition that does not contain lecithin and thus does not form LNP was prepared. In the oil phase preparation step, 0.2 wt% cholesterol, 0.2 wt% lauric acid, 0.5 wt% tocopherol, and 1.0 wt% retinal were heated and dissolved at 55°C to prepare the oil phase. No lecithin was added. In the aqueous phase preparation step, 41.6 wt% purified water, 20.0 wt% isopentyldiol, 10.0 wt% 1,2-hexanediol, 10.0 wt% glycerin, and 10.0 wt% sucrose were mixed while heating at 55°C to prepare the aqueous phase. In the emulsion formation step, the oil phase was slowly added to the aqueous phase while homogenizing with a homomixer at 8,000 rpm for 10 minutes to form an emulsion. In the additive mixing step, after cooling the emulsion to 35°C or lower, 2.0 wt% of polyglyceryl-10 oleate, 2.0 wt% of polysorbate 20, 2.0 wt% of polysorbate 80, and 0.5 wt% of ethylhexylglycerin were added and uniformly mixed.

[0211] Comparative Examples 6 and 7

[0212] An LNP-type cosmetic composition was prepared by setting the content of ferulic acid outside the scope of the present invention. Comparative Example 6 used 0.05 wt% of ferulic acid, and Comparative Example 7 used 1.5 wt% of ferulic acid. In the oil phase preparation step, the same method as in Example 12 was used, except that the content of ferulic acid was changed as described above. In the aqueous phase preparation step, the content of purified water was adjusted to 40.55 wt% for Comparative Example 6 and 39.1 wt% for Comparative Example 7. The other aqueous phase compositions were the same as in Example 2. The LNP formation step and the additive blending step were performed in the same way as in Example 2.

[0213] Comparative Examples 8 and 9

[0214] An LNP-type cosmetic composition was prepared by setting the ectoin content outside the scope of the present invention. Comparative Example 8 used 0.05 wt% of ectoin, and Comparative Example 9 used 4.0 wt% of ectoin. The oil phase preparation step was performed in the same manner as in Example 2. The aqueous phase preparation step was performed in the same manner as in Example 15, except that the ectoin content was changed as described above. The content of purified water was adjusted to 40.55 wt% for Comparative Example 8 and 36.6 wt% for Comparative Example 9. The LNP formation step and the additive blending step were performed in the same manner as in Example 2.

[0215] Experimental Example 1: Photostability Evaluation

[0216] The photostability of retinal was evaluated for the compositions prepared in Examples 1 to 23 and Comparative Examples 1 to 9. Each composition was placed in a clear glass container and irradiated under a UV lamp for 48 hours. The UV irradiation condition was 2.0 mW / cm² at a UVA wavelength of 340 nm. 2 The intensity was set to [value]. The retinal content before and after UV irradiation was quantified using high-performance liquid chromatography to calculate the retinal retention rate.

[0217] As a result of evaluating photostability according to changes in retinal content, Example 1 had a retinal retention rate of 78.2%, Example 2 had 82.5%, Example 3 had 81.8%, and Example 4 had 80.3%. Comparative Example 1 had 75.1%, and Comparative Example 2 had 68.4%.

[0218] As a result of evaluating photostability according to changes in surfactant content, Example 5 had a retinal retention rate of 79.3%, Example 6 had 82.5%, and Example 7 had 83.1%. Comparative Example 3 had 72.6%.

[0219] As a result of evaluating photostability according to changes in diol content, Example 8 had a retinal retention rate of 77.4%, Example 9 had 82.5%, and Example 10 had 83.8%. Comparative Example 4 had 69.2%.

[0220] As a result of the photostability evaluation based on whether LNP was formed, Comparative Example 5 had a retinal retention rate of 58.3%. As a result of the photostability evaluation based on changes in ferulic acid content, Example 11 had a retinal retention rate of 84.7%, Example 12 had 89.2%, and Example 13 had 90.1%. Comparative Example 6 had 83.1% and Comparative Example 7 had 87.5%, but discoloration of the composition was observed in Comparative Example 7.

[0221] As a result of evaluating photostability according to changes in fullerenol content, Example 18 had a retinal retention rate of 85.6%, Example 19 had 88.9%, and Example 20 had 90.8%.

[0222] As a result of the optical stability evaluation following the application of a multi-stabilization system, Example 21 had a retinal retention rate of 93.5%, and Example 23 had 94.2%.

[0223] Experimental Example 2: Evaluation of Thermal Stability and Oxidation Stability

[0224] The thermal stability and oxidation stability of retinal were evaluated for the compositions prepared in Examples 1 to 23 and Comparative Examples 1 to 9. Each composition was placed in a sealed container and stored in a 45°C incubator for 4 weeks. The retinal content before and after storage was quantified using high-performance liquid chromatography to calculate the retinal retention rate.

[0225] As a result of evaluating thermal stability according to changes in retinal content, Example 1 had a retinal retention rate of 81.5%, Example 2 had 85.2%, Example 3 had 84.6%, and Example 4 had 82.1%. Comparative Example 1 had 79.3%, and Comparative Example 2 had 71.8%.

[0226] As a result of evaluating thermal stability according to changes in surfactant content, Example 5 had a retinal retention rate of 82.4%, Example 6 had 85.2%, and Example 7 had 85.8%. Comparative Example 3 had 76.1%.

[0227] As a result of evaluating thermal stability according to changes in diol content, Example 8 had a retinal retention rate of 80.2%, Example 9 had 85.2%, and Example 10 had 86.4%. Comparative Example 4 had 72.5%.

[0228] As a result of the thermal stability evaluation based on whether LNP was formed, Comparative Example 5 had a retinal retention rate of 63.7%.

[0229] As a result of evaluating thermal stability according to changes in ectoin content, Example 14 had a retinal retention rate of 87.3%, Example 15 had 89.8%, and Example 16 had 91.2%. Comparative Example 8 had 85.4% and Comparative Example 9 had 90.5%, but a change in the viscosity of the composition was observed in Comparative Example 9.

[0230] As a result of evaluating thermal stability with the combined use of ectoin and hydroxyectoin, Example 17 had a retinal retention rate of 92.4%.

[0231] As a result of evaluating thermal stability according to changes in fullerenol content, Example 18 had a retinal retention rate of 87.1%, Example 19 had 89.5%, and Example 20 had 90.9%.

[0232] As a result of the thermal stability evaluation following the application of a multi-stabilization system, Example 21 had a retinal retention rate of 94.8%, and Example 23 had 95.3%.

[0233] Experimental Example 3: Measurement of LNP Particle Size and Distribution

[0234] The average particle size and particle size distribution of LNP were measured for the compositions prepared in Examples 1 to 10, Example 22, Example 23, and Comparative Examples 1 to 5. The average particle size and polydispersity index were measured using dynamic light scattering. The measurement temperature was set to 25°C, and each sample was measured after diluting it 100 times with purified water.

[0235] Specifically, a light scattering particle size analyzer (e.g., Otsuka Electronics’ ELS-Z series, etc.) was used as the measuring equipment, and the measurement temperature was set to 25.0℃, the refractive index of the dispersion medium (purified water) to 1.3328, and the viscosity to 0.8878 cP to ensure the precision of the analysis. For the particle size analysis algorithm, the cumulant analysis method was applied to calculate the average particle size (Z-average diameter) and the polydispersity index (PDI).

[0236] As shown in Fig. 2, the particle size analysis results of Example 1 exhibited a very narrow and uniform monodisperse form. As a result of measuring particle size according to changes in retinal content, Example 1 had an average particle size of 144.7 nm and a polydispersity index of 0.080. Example 2 had an average particle size of 172.5 nm and a polydispersity index of 0.22. Example 3 had an average particle size of 178.1 nm and a polydispersity index of 0.25. Example 4 had an average particle size of 185.6 nm and a polydispersity index of 0.27. Comparative Example 1 had an average particle size of 165.2 nm and a polydispersity index of 0.23. Comparative Example 2 had an average particle size of 198.4 nm and a polydispersity index of 0.31.

[0237] Figure 2 is a report on the particle size analysis results of an LNP-type cosmetic composition prepared according to Example 1 of the present invention. Referring to Figure 2, the LNP of Example 1 formed a nano-size with an average particle size of 144.7 nm and simultaneously exhibited an extremely low polydispersity index (PDI) of 0.080. In particular, a single peak was observed with a very narrow full-width value in all graphs of intensity distribution, volume distribution, and number distribution, which proves that particles in a very uniform monodisperse state were formed through the manufacturing process of the present invention. Furthermore, the fact that the autocorrelation function (ACF) fitting curve exhibits a smooth decay shape without noise supports the statistically very high reliability of the measured data.

[0238] The PDI value of Example 1 was measured to be 0.080, which indicates a high degree of monodispersity that is extremely rare in conventional nanoparticle dispersion systems. This uniformity is achieved by the unique process of the present invention, which combines high-pressure homogenization and ultrasonic treatment, and plays a key role in inhibiting particle aggregation or sedimentation during long-term storage.

[0239] As a result of measuring particle size according to changes in surfactant content, Example 5 had an average particle size of 195.8 nm and a polydispersity index of 0.28. Example 6 had an average particle size of 172.5 nm and a polydispersity index of 0.22. Example 7 had an average particle size of 158.3 nm and a polydispersity index of 0.19. Comparative Example 3 had an average particle size of 215.6 nm and a polydispersity index of 0.35.

[0240] As a result of measuring particle size according to changes in diol content, Example 8 had an average particle size of 182.4 nm and a polydispersity index of 0.26. Example 9 had an average particle size of 172.5 nm and a polydispersity index of 0.22. Example 10 had an average particle size of 165.7 nm and a polydispersity index of 0.20. Comparative Example 4 had an average particle size of 225.3 nm and a polydispersity index of 0.38.

[0241] As a result of measuring particle size according to whether LNP was formed, Comparative Example 5 had an average emulsion droplet size of 856.2 nm and a polydispersity index of 0.52.

[0242] As a result of measuring particle size following the application of a two-step homogenization process, Example 22 had an average particle size of 98.5 nm and a polydispersity index of 0.15. Example 23 had an average particle size of 95.2 nm and a polydispersity index of 0.14.

[0243] In general lipid nanoparticle formulations, a PDI value of 0.2 or less is considered uniform; however, the PDI value of 0.080 achieved in Example 1 of the present invention signifies a 'super-uniform' state in which the particle size distribution is extremely concentrated. Such results are difficult to achieve solely through the combination of ingredients and are attributed to the synergistic effect of the optimized two-step process combination of ultrasonic treatment and high-pressure homogenization presented in the present invention. This uniformity of particles is a key factor in dramatically improving the physical stability of the formulation by suppressing coalescence or precipitation between particles during long-term storage.

[0244] Experimental Example 4: Long-term stability evaluation

[0245] Long-term storage stability was evaluated for the compositions prepared in Examples 1 to 23 and Comparative Examples 1 to 9. Each composition was placed in a light-shielding container and stored at 25°C for 12 weeks, during which changes in appearance, phase separation, degree of discoloration, and scent were observed. Appearance stability was evaluated on a 0 to 5-point scale, where 5 points indicated no change, 4 points indicated minor change, 3 points indicated slight change, 2 points indicated moderate change, 1 point indicated severe change, and 0 points indicated a change that makes the product unusable.

[0246] As a result of the long-term stability evaluation according to changes in retinal content, Example 1 had an appearance stability score of 4.5 points, and no phase separation or discoloration was observed. Example 2 had a score of 4.8 points, and no phase separation or discoloration was observed. Example 3 had a score of 4.6 points, and no phase separation or discoloration was observed. Example 4 had a score of 4.3 points, and slight yellowing was observed. Comparative Example 1 had a score of 4.2 points, and no phase separation or discoloration was observed. Comparative Example 2 had a score of 3.1 points, and phase separation and yellowing were observed.

[0247] As a result of evaluating long-term stability according to changes in surfactant content, Example 5 had an appearance stability score of 4.0 points and slight creaming was observed. Example 6 had a score of 4.8 points and no phase separation or discoloration was observed. Example 7 had a score of 4.9 points and no phase separation or discoloration was observed. Comparative Example 3 had a score of 2.8 points and upper layer separation was observed.

[0248] As a result of evaluating long-term stability according to changes in diol content, Example 8 had an appearance stability score of 4.2 points and a slight increase in turbidity was observed. Example 9 had a score of 4.8 points and no phase separation or discoloration was observed. Example 10 had a score of 4.7 points and no phase separation or discoloration was observed. Comparative Example 4 had a score of 2.5 points and phase separation and precipitation were observed.

[0249] As a result of the long-term stability evaluation based on whether LNP was formed, Comparative Example 5 had an appearance stability score of 1.8 points, and phase separation, precipitation, and discoloration were observed.

[0250] As a result of evaluating long-term stability according to changes in ferulic acid content, Example 11 had an appearance stability score of 4.6 points, Example 12 had 4.9 points, and Example 13 had 4.7 points. Comparative Example 6 had 4.5 points, Comparative Example 7 had 3.5 points, and yellowing was observed.

[0251] As a result of the long-term stability evaluation according to the change in ectoin content, Example 14 had an appearance stability score of 4.7 points, Example 15 had 4.9 points, and Example 16 had 4.8 points. Comparative Example 8 had 4.4 points and Comparative Example 9 had 4.0 points, and an increase in viscosity was observed.

[0252] As a result of the long-term stability evaluation following the application of a multi-stabilization system, Example 21 had an appearance stability score of 5.0 points, and Example 23 had a score of 5.0 points.

[0253] Experimental Example 5: Skin Irritation Evaluation

[0254] Skin irritation was evaluated for the compositions prepared in Examples 2, 4, 12, 17, 21, and 23, as well as Comparative Examples 2 and 5. A human patch test was conducted on 15 healthy adult men and women. 20 µL of each composition was applied to a pin chamber and closed for 24 hours on the inner skin of the upper arm. Skin reactions were observed at 30 minutes and 24 hours after patch removal. Skin irritation scores were evaluated on a 0 to 4-point scale according to the criteria of the International Contact Dermatitis Study Group, where 0 indicates no reaction, 1 indicates mild erythema, 2 indicates distinct erythema, 3 indicates erythema and papules, and 4 indicates erythema and vesicles. The mean irritation index was calculated by dividing the sum of the irritation scores of all subjects by the number of subjects.

[0255] Example 2, containing 1.0 wt% retinal, had an average irritation index of 0.27 at 30 minutes after patch removal and 0.13 at 24 hours. Example 4, containing 2.0 wt% retinal, had an average irritation index of 0.53 at 30 minutes after patch removal and 0.33 at 24 hours.

[0256] Example 12, containing ferulic acid, had an average irritation index of 0.20 at 30 minutes after patch removal and 0.07 at 24 hours.

[0257] Example 17, containing ectoin and hydroxyectoin, had an average irritation index of 0.13 at 30 minutes after patch removal and 0.00 at 24 hours.

[0258] Example 21, which includes a multi-stabilization system, had an average irritation index of 0.07 at 30 minutes after patch removal and 0.00 at 24 hours. Example 23 had an average irritation index of 0.07 at 30 minutes after patch removal and 0.00 at 24 hours.

[0259] Comparative Example 2, containing 2.5% by weight of retinal, had an average irritation index of 1.13 at 30 minutes after patch removal and 0.73 at 24 hours.

[0260] Comparative Example 5, which did not form LNP, had an average stimulation index of 0.93 at 30 minutes after patch removal and 0.60 at 24 hours.

[0261] Experimental Example 6: Skin Penetration Evaluation

[0262] Skin penetration rates were evaluated for the compositions prepared in Examples 2, 9, 21, 22, and 23, and Comparative Examples 4 and 5. The penetration rate of retinal through an artificial skin membrane was measured using a Franz diffusion cell. A Strat-M membrane was used as the artificial skin membrane, and a phosphate-buffered saline solution with a pH of 7.4 was used as the aqueous solution. 500 µL of each composition was applied to a donor chamber, and penetration experiments were performed at 32°C for 24 hours. Receptor solutions were collected at 6, 12, and 24 hours, and the retinal content was quantified using high-performance liquid chromatography. The cumulative penetration amount was calculated as the amount of retinal penetrated per unit area.

[0263] Example 2 showed a cumulative penetration amount of 12.5 μg / cm² after 6 hours. 2 It was, and at 12 hours it was 28.3 μg / cm² 2 It was, and at 24 hours, 45.6 μg / cm² 2 It was.

[0264] Example 9, which has a high diol content, had a cumulative penetration amount of 12.5 μg / cm³ after 6 hours. 2 It was, and at 12 hours it was 28.3 μg / cm² 2 It was, and at 24 hours, 45.6 μg / cm² 2 It was.

[0265] Example 21, which includes a multi-stabilization system, has a cumulative penetration amount of 14.2 g / cm³ at the elapsed time of 6 hours. 2 It was, and at 12 hours it was 32.1 μg / cm² 2 It was, and at 24 hours, 51.8 μg / cm² 2 It was.

[0266] Example 22, to which a two-stage homogenization process was applied, had a cumulative penetration amount of 18.7 μg / cm³ after 6 hours. 2 It was, and at 12 hours it was 41.5 μg / cm² 2It was, and at 24 hours, it was 68.2 μg / cm³ 2 It was.

[0267] Example 23, which applied both a multi-stabilization system and a two-stage homogenization process, had a cumulative penetration amount of 20.3 μg / cm³ after 6 hours. 2 It was, and at 12 hours it was 45.8 μg / cm² 2 It was, and at 24 hours, 74.5 μg / cm² 2 It was.

[0268] Comparative Example 4, with a low diol content, had a cumulative penetration amount of 8.3 g / cm² after 6 hours. 2 It was, and at 12 hours it was 18.9 μg / cm² 2 It was, and at 24 hours, 31.2 μg / cm² 2 It was.

[0269] Comparative Example 5, which did not form LNP, had a cumulative penetration amount of 5.1 g / cm³ after 6 hours. 2 It was, and at 12 hours it was 12.4 μg / cm² 2 It was, and at 24 hours, 21.8 μg / cm² 2 It was.

[0270] Although embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and it will be obvious to those skilled in the art that various modifications and variations are possible within the scope of the technical concept of the present invention as described in the claims.

Claims

Claim 1 A method for preparing an LNP-type cosmetic composition, comprising: an oil phase preparation step of preparing an oil phase by mixing lecithin, cholesterol, lauric acid, tocopherol, and retinal; a water phase preparation step of preparing a water phase by mixing purified water, isopentyldiol, 1,2-hexanediol, glycerin, and sucrose; an LNP formation step of mixing and homogenizing the oil phase and the water phase to form an LNP; and an additive blending step of adding polyglyceryl-10 oleate, polysorbate 20, polysorbate 80, and ethylhexylglycerin; wherein the LNP formation step comprises: an ultrasonic treatment step of applying ultrasound to a mixture of the oil phase and the water phase; and a high-pressure homogenization step of performing high-pressure homogenization on the mixture that has undergone the ultrasonic treatment step. Claim 2 A method for preparing an LNP-type cosmetic composition according to claim 1, wherein, in the oil phase preparation step, the content of the retinal is 0.5 to 5.0 weight% relative to the total weight of the composition. Claim 3 A method for preparing an LNP-type cosmetic composition according to claim 1, wherein, in the oil phase preparation step, the weight ratio of the lecithin, the cholesterol, and the lauric acid is 1.0 : 0.1 to 0.4 : 0.1 to 0.

4. Claim 4 A method for preparing an LNP-type cosmetic composition according to claim 1, wherein, in the ultrasonic treatment step, the frequency of the ultrasound is 15 to 50 kHz and the treatment time is 3 to 20 minutes. Claim 5 A method for preparing an LNP-type cosmetic composition according to claim 1, wherein ferulic acid and ascorbyl palmitate are additionally mixed in the oil phase preparation step. Claim 6 A method for preparing an LNP-type cosmetic composition according to claim 1, wherein, in the aqueous phase preparation step, ectoin and hydroxyectoin are additionally mixed.

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