Low-irritant cosmetic composition comprising high concentration retinoid

Abstract

The present invention relates to a cosmetic composition containing a high concentration of retinoid to improve wrinkled skin, and more specifically, relates to a cholesteric liquid crystal cosmetic composition containing retinol, the composition having an excellent wrinkle-improving effect by containing a high concentration of retinoid while also being significantly less irritating to the skin.

Description

Hypoallergenic cosmetic composition containing high concentrations of retinoids

[0001] The present invention relates to a cosmetic composition containing a high concentration of retinoid to improve wrinkled skin, and specifically, to a retinoid-containing cholesteric liquid crystal cosmetic composition containing a high concentration of retinoid that has excellent wrinkle-improving effects while significantly reducing skin irritation.

[0002] Generally, liquid crystals refer to various structures existing in an intermediate state between solid and liquid, and in the cosmetics industry, they are used for moisturizing, stabilizing active substances, and regulating delivery systems. Lipophilic liquid crystals refer to lamellar liquid crystals formed by organic molecules, such as surfactants, which possess both hydrophilic and lipophilic (hydrophobic) parts; these molecules are arranged in a specific pattern where the hydrophilic parts align with each other and the hydrophobic parts align with each other to form multiple layers. Lamellar liquid crystals are generated at the interface when water-containing emulsions are prepared, thereby stabilizing the emulsion. Furthermore, possessing a structure similar to the composition of lipids between biological cell membranes, they function as a protective skin barrier, provide moisturizing effects, enhance the preservation stability of various water-soluble and oil-soluble active ingredients, and serve as an effective delivery medium.

[0003] Examples of stabilizing active ingredients using lamellar liquid crystals include a cosmetic composition in which an oil-soluble active substance is stabilized (KR 10-0320087) and a liquid crystal gel in which retinyl palmitate is stabilized and a cosmetic composition containing the same (KR 10-0146221). KR 10-0320087 relates to a cosmetic composition in which retinol and its derivatives are stabilized. It is characterized by being prepared in a non-aqueous solvent having a lamellar liquid crystal structure to prevent retinol and its derivatives from being destabilized by ultraviolet rays and temperature, and then added to an oil-in-water type emulsion base. Since the active ingredient is slowly released by the lamellar liquid crystals, this composition can partially alleviate skin irritation caused by retinol, but there is a problem that it is insufficient at high concentrations rather than low concentrations.

[0004] Thermotropic liquid crystals are formed by changes in temperature; cholesteric liquid crystals, a type of thermotropic liquid crystal, possess unique optical properties such as interference colors and high optical rotation when circularly polarized light is applied under white light, and these properties are utilized in the cosmetics industry.

[0005] Liquid crystals are also classified into smectic, nematic, and cholesteric liquid crystals depending on their arrangement method. When cholesteric liquid crystals are formed, they reflect light in the visible light spectrum and can be seen with the naked eye.

[0006] Retinol is a type of Vitamin A, also known as pure vitamin. It is an FDA-approved ingredient for its wrinkle-reducing and anti-aging effects and is widely used in functional anti-aging cosmetics. However, retinol often causes skin irritation. Since the likelihood of irritation varies significantly from person to person and the exact mechanism of its occurrence has not yet been fully elucidated, it is currently common practice to determine the presence of irritation by directly using retinol products.

[0007] Skin irritation caused by retinol manifests as a complex combination of various inflammatory reactions, such as itching, stinging, and burning sensations, as well as erythema and edema. Therefore, relying solely on a single anti-inflammatory ingredient to alleviate this irritation is insufficient. In other words, to apply the anti-aging benefits of retinol to a wider range of people, the development of hypoallergenic cosmetics that minimize skin irritation must be prioritized.

[0008] One objective of the present invention is to provide a cholesteric liquid crystal cosmetic composition containing a high concentration of retinoid for the improvement of acne, pigmentation, keratinization, or wrinkles, while significantly reducing skin irritation.

[0009] Another objective of the present invention is to provide a cosmetic composition and a quasi-drug composition comprising the above composition as an active ingredient.

[0010] The present invention provides a cholesteric liquid crystal composition comprising cholesteryl isostearate, cholesteryl nonanoate, cholesteryl chloride, and cholesteryl stearate; and a low-irritation cosmetic composition comprising a retinoid.

[0011] The present invention provides a cholesteric liquid crystal composition comprising cholesteryl isostearate, cholesteryl nonanoate, cholesteryl chloride, and cholesteryl stearate; and a low-irritation topical quasi-drug composition comprising a retinoid.

[0012] In addition, the present invention provides a cholesteric liquid crystal composition comprising cholesteryl isostearate, cholesteryl nonanoate, cholesteryl chloride, and cholesteryl stearate; and a pharmaceutical composition for the treatment and prevention of skin diseases comprising a retinoid.

[0013] The cosmetic composition according to the present invention contains a high concentration of retinoid components, thereby providing an excellent effect in improving skin wrinkles while significantly reducing skin irritation.

[0014] The present invention will be described in more detail below.

[0015] In the present invention, "cholesteric liquid crystal" refers to a composition comprising cholesteryl isostearate, cholesteryl nonanoate, cholesteryl chloride, and cholesteryl stearate. Cholesteric liquid crystal is highly effective for moisturizing the skin and can protect the skin from external stimuli without side effects, so it can be used to improve the skin barrier of damaged skin.

[0016] In the present invention, "retinoid" is a term encompassing all components derived from Vitamin A, including retinoic acid, retinol, and retinal. In the present invention, as the retinoid, preferably an irritating retinoid, and more preferably retinol, may be used. Retinoids are effective in improving skin aging, managing acne and pores, and alleviating pigmentation.

[0017] To address the skin irritation issues that may arise when retinol is included in high concentrations, the inventors incorporated retinol within a layered structure of cholesteric liquid crystals. As a result, they confirmed the effect of improved skin irritation through a sustained-release (SR) formulation that controls the amount and speed of retinol release into the skin upon application, thereby completing the present invention.

[0018] Accordingly, the present invention provides a cholesteric liquid crystal composition comprising cholesteryl isostearate, cholesteryl nonanoate, cholesteryl chloride, and cholesteryl stearate; and a low-irritation cosmetic composition comprising a retinoid.

[0019] More preferably, the cholesteric liquid crystal composition may consist of cholesteryl isostearate, cholesteryl nonanoate, cholesteryl chloride, and cholesteryl stearate.

[0020] The above cholesteric liquid crystal composition may have a weight ratio of cholesteryl isostearate : cholesteryl nonanoate : cholesteryl chloride : cholesteryl stearate of 35~65 : 15~35 : 10~25 : 0.1~10, more specifically 35~55 : 15~35 : 15~20 : 0.5~5, and more preferably 50~60 : 20~30 : 10~20 : 0.5~2, and the sum of each weight ratio may satisfy 100.

[0021] The above cholesteric liquid crystal composition comprises, based on the total weight of the cosmetic composition, 30 to 95 wt%, 40 to 95 wt%, 50 to 95 wt%, 60 to 95 wt%, 65 to 95 wt%, 70 to 95 wt%, 75 to 95 wt%, 80 to 95 wt%, 30 to 90 wt%, 40 to 90 wt%, 50 to 90 wt%, 60 to 90 wt%, 65 to 90 wt%, 70 to 90 wt%, 75 to 90 wt%, 80 to 90 wt%, 30 to 88 wt%, 40 to 88 wt%, 50 to 88 wt%, 60 to 88 wt%, 65 to 88 wt%, 70 to 88 wt%, 75 to 88 wt%. It may contain 80 to 88 weight percent.

[0022] Preferably, the cosmetic composition of the present invention may comprise, in addition to the cholesteric liquid crystal, 0.5 to 3 weight% of an emulsifier, 3 to 40 weight% of an oil, 0.2 to 3 weight% of an anti-inflammatory agent, and 0.1 to 3 weight% of an antioxidant.

[0023] The above retinoid may be included in an amount of 0.075 to 3 weight percent based on the total weight of the cosmetic composition, but is not limited thereto. For example, 0.075 to 3 wt%, 0.1 to 3 wt%, 0.2 to 3 wt%, 0.3 to 3 wt%, 0.4 to 3 wt%, 0.5 to 3 wt%, 0.075 to 2.5 wt%, 0.1 to 2.5 wt%, 0.2 to 2.5 wt%, 0.3 to 2.5 wt%, 0.4 to 2.5 wt%, 0.5 to 2.5 wt%, 0.075 to 2 wt%, 0.1 to 2 wt%, 0.2 to 2 wt%, 0.3 to 2 wt%, 0.4 to 2 wt%, 0.5 to 2 wt%, 0.075 to 1.5 wt%, 0.1 to 1.5 wt%, 0.2 to 1.5 wt%, 0.3 to It may be 1.5 wt%, 0.4 to 1.5 wt%, 0.5 to 1.5 wt%, 0.075 to 1 wt%, 0.1 to 1 wt%, 0.2 to 1 wt%, 0.3 to 1 wt%, 0.4 to 1 wt%, or 0.5 to 1 wt%.

[0024] The composition of the present invention substantially does not contain water. More specifically, it may contain less than 1 weight% of water, less than 0.5 weight%, less than 0.1 weight%, or less than 0.01 weight%, and preferably may be anhydrous, but is not limited thereto.

[0025] Since the content of the emulsifier used in the hypoallergenic cosmetic composition of the high-concentration retinoid-containing cholesteric liquid crystal of the present invention can affect formulation stability, it is preferable to use 0.5 to 3% by weight relative to the total weight of the composition. The emulsifier may be a synthetic surfactant or a natural surfactant, and for example, in the present invention, hydrogenated lecithin, a natural surfactant, was used.

[0026] The oil of the present invention is not particularly limited in type, and conventional oils used in cosmetic compositions may be used. Specifically, esters such as octyldodecyl isostearate, neopentyl glycol diethylhexanoate, neopentyl glycol diisononanoate, neopentyl glycol diisostearate, and triethylhexanoin; vegetable oils such as avocado oil, wheat germ oil, rosehip oil, almond oil, olive oil, castor oil, camellia oil, corn oil, safflower oil, soybean oil, rapeseed oil, macadamia nut oil, jojoba oil, palm oil, and coconut oil; and C8-12 acid triglyceride, C12-18 acid triglyceride, and caprylic / capric triglyceride may be used alone or in combination with two or more types of oils.

[0027] The anti-inflammatory agent of the present invention may be one or more selected from the group consisting of stearyl glycyrrhetinate, glycyrrhetinic acid, hydroxyphenylpropamidobenzoic acid, 4-t-butyl cyclohexanol, and omega-9, but is not limited thereto.

[0028] The antioxidant of the present invention may be one or more selected from the group consisting of tocopherol, tocopherol acetate, ascorbyl palmitate, ascorbyl stearate, ascorbillinoleate, ascorbyl tetraisopalmitate, butylated hydroxytoluene, and pentaerythrityl tetra-di-t-butylhydroxy hydrocinnamate, but is not limited thereto.

[0029] According to one embodiment of the present invention, to evaluate skin irritation of Examples 1 to 3, in which retinol at a concentration of 0.3 to 1.5 weight% is contained in a cholesteric liquid crystal, and Comparative Examples 1 to 3, in which the same amount of retinol as the examples is contained without a cholesteric liquid crystal, an evaluation was conducted using a human patch test method.

[0030] As a result, as shown in Table 4, in the case of Examples 1 to 3 according to the present invention, it was observed that the skin release amount of retinol upon application was controlled by encapsulating retinol within a cholesteric liquid crystal layered structure, thereby significantly reducing irritation. In particular, even when the retinol content was 1.0 wt% or more, the irritation index was evaluated to be 0.2 or less, confirming that it is low-irritation. On the other hand, it was confirmed that significant skin irritation occurred when a cholesteric liquid crystal composition was not used, as in Comparative Examples 1 and 3. In particular, it was found that Comparative Examples 7 to 9, which are O / W emulsion formulations containing a lamellar liquid crystal base, exhibited very high skin irritation compared to Comparative Examples 1 to 3, which are anhydrous oil formulations. From the above results, it was confirmed that when a cholesteric liquid crystal composition is used, skin irritation is significantly improved even when the retinol component is included at a high concentration, and thus, a composition safe for the skin can be provided.

[0031] The composition of the present invention may be used to improve acne, pigmentation, keratinization, or wrinkles.

[0032] In one embodiment of the present invention, the cosmetic composition is not particularly limited in its formulation and can be appropriately selected according to the purpose. For example, it may be prepared in one or more formulations selected from the group consisting of skin lotion, skin softener, skin toner, lotion, milk lotion, moisture lotion, nourishing lotion, massage cream, nourishing cream, moisture cream, hand cream, foundation, makeup base, primer, essence, nourishing essence, pack, soap, peeling gel, peeling pack, peeling cream, cleansing foam, cleansing lotion, cleansing cream, cleansing gel, cleansing oil, body lotion, and body cleanser.

[0033] The present invention provides a cholesteric liquid crystal composition comprising cholesteryl isostearate, cholesteryl nonanoate, cholesteryl chloride, and cholesteryl stearate; and a low-irritation topical quasi-drug composition comprising a retinoid.

[0034] The above cholesteric liquid crystal composition may consist of cholesteryl isostearate, cholesteryl nonanoate, cholesteryl chloride, and cholesteryl stearate.

[0035] In one embodiment of the present invention, "quasi-drug" refers to an article corresponding to one of the following: fibers, rubber products, or similar items used for the purpose of treating, alleviating, managing, or preventing diseases in humans or animals; items similar thereto that have a weak effect on the human body or do not act directly on the human body and are not instruments or machines; and preparations used for sterilization, insecticidal, and similar purposes for the prevention of infectious diseases; excluding articles used for the purpose of diagnosing, treating, alleviating, managing, or preventing diseases in humans or animals that are not instruments, machines, or devices, and articles used for the purpose of exerting pharmacological effects on the structure and function of humans or animals that are not instruments, machines, or devices. Furthermore, the above quasi-drug may include external skin preparations or personal hygiene products.

[0036] The above external skin preparations are not specifically limited thereto, but specifically may be manufactured and used in the form of ointments, lotions, sprays, patches, creams, powders, suspensions, gels, or gels. The above personal hygiene products are not specifically limited thereto, but specifically may be soap, cosmetics, wet wipes, tissues, shampoo, skin cream, face cream, toothpaste, lipstick, perfume, makeup, foundation, blush, mascara, eyeshadow, sunscreen lotion, hair care products, air freshener gel, or cleansing gel. In addition, other examples of the quasi-drug composition of the present invention include disinfectant cleansers, shower foams, mouthwash, wet wipes, detergent soaps, hand washes, humidifier fillers, masks, ointments, or filter fillers.

[0037] The present invention provides a cholesteric liquid crystal composition comprising cholesteryl isostearate, cholesteryl nonanoate, cholesteryl chloride, and cholesteryl stearate; and a pharmaceutical composition for the treatment and prevention of skin diseases comprising a retinoid.

[0038] The above cholesteric liquid crystal composition may consist of cholesteryl isostearate, cholesteryl nonanoate, cholesteryl chloride, and cholesteryl stearate.

[0039] The above skin disease may be selected from the group consisting of acne and psoriasis, but is not limited thereto.

[0040] The above pharmaceutical composition may further include a suitable carrier, excipient, or diluent commonly used in the manufacture of pharmaceutical compositions.

[0041] Examples of carriers, excipients, or diluents usable in the present invention include lactose, dextrose, sucrose, sorbitol, mannitol, xylitol, erythritol, maltitol, starch, acacia gum, alginate, gelatin, calcium phosphate, calcium silicate, cellulose, methyl cellulose, microcrystalline cellulose, polyvinylpyrrolidone, water, methylhydroxybenzoate, propylhydroxybenzoate, talc, magnesium stearate, or mineral oil.

[0042] The pharmaceutical composition according to the present invention can be formulated and used in the form of oral formulations such as powders, granules, tablets, capsules, suspensions, emulsions, syrups, and aerosols, external formulations, suppositories, and sterile injectable solutions, respectively, according to conventional methods.

[0043] When formulating, it is prepared using diluents or excipients such as commonly used fillers, extenders, binders, wetting agents, disintegrants, and surfactants. Solid dosage forms for oral administration include tablets, pills, powders, granules, and capsules, and these solid dosage forms may be prepared by mixing the above compound with at least one excipient, for example, starch, calcium carbonate, sucrose or lactose, gelatin, etc.

[0044] In addition to simple excipients, lubricants such as magnesium stearate and talc are also used. Liquid formulations for oral administration include suspensions, oral liquids, emulsions, and syrups, and in addition to commonly used simple diluents such as water and liquid paraffin, various excipients, such as humectants, sweeteners, flavorings, and preservatives, may be included.

[0045] Preparations for parenteral administration include sterile aqueous solutions, non-aqueous solvents, suspensions, emulsions, lyophilized preparations, and suppositories. As non-aqueous solvents and suspensions, propylene glycol, polyethylene glycol, vegetable oils such as olive oil, and injectable esters such as ethyl oleate may be used. As bases for suppositories, Witepsol, Macrogol, Tween 61, cocoa paste, laurin paste, glycerogelatin, etc. may be used.

[0046] In addition, the present invention provides a method for preventing or alleviating skin irritation derived from retinoids.

[0047] The above method may be a method of locally applying a composition comprising a cholesteric liquid crystal composition including cholesteryl isostearate, cholesteryl nonanoate, cholesteryl chloride, and cholesteryl stearate, and a retinoid to a target.

[0048] Hereinafter, examples and test examples will be described in detail to aid in understanding the present invention. However, the examples and test examples according to the present invention may be modified in various different forms, and the scope of the present invention should not be interpreted as being limited to the following examples and test examples. The examples and test examples of the present invention are provided by way of example to more completely explain the present invention to those with average knowledge in the art.

[0049] <Preparation Example>

[0050] 1. Preparation of Examples 1 to 3 and Comparative Examples 1 to 3

[0051] According to the composition of Table 1 below, Examples 1 to 3 were prepared by weighing raw materials 2 to 8 and a cholesteric liquid crystal composition consisting of 18 g of cholesteryl chloride, 55 g of cholesteryl isostearate, 26 g of cholesteryl nonanoate, and 1 g of cholesteryl stearate into a beaker, heating to 75–80°C, and then uniformly mixing using a paddle mixer for 30 minutes. Subsequently, the mixture was cooled to 50°C, then raw material 9, retinol, was added and mixed for another 10 minutes. Afterward, the mixture was cooled to 25°C and degassed to prepare a retinol-containing cholesteric liquid crystal cosmetic. Comparative Examples 1 to 3 were prepared by replacing the cholesteric liquid crystal composition with caprylic / capric triglyceride and using the same method to prepare a retinol-containing oil cosmetic.

[0052] Raw Material Name (Weight %) Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Comparative Example 3 1 Cholesteric Liquid Crystal Composition 86.285.585.0---2 Caprylic / Capric Triglyceride 10.010.010.096.295.595.03 Stearyl Glycyrrhetinate 0.50.50.50.50.50.54 Tocopherol 0.50.50.50.50.50.55 Hydrogenated Lecithin 1.01.01.01.01.01.06 Stearyl Alcohol 0.50.50.50.50.50.57 Behenic Acid 0.50.50.50.50.50.58 Dimethicone 0.50.50.50.50.50.59 Retinol 0.31.01.50.31.01.5

[0053] 2. Preparation of Comparative Examples 4 to 6

[0054] To verify whether the same effect would be observed with lamellar liquid crystals rather than cholesteric liquid crystals, a lamellar liquid crystal base containing retinol was prepared. Specifically, raw materials 1 to 5 were weighed into a beaker according to the composition of Table 2 below and heated to 85–90°C to dissolve them. Subsequently, the homomixer was set to 300–400 rpm and stirred while cooling to 65–70°C. Then, while continuing to stir, raw material 6, retinol, was slowly added and emulsified for 4–6 minutes. Subsequently, the mixture was cooled to 50–55°C and then naturally cooled to room temperature to prepare a lamellar liquid crystal base containing retinol.

[0055] Ingredient Name (Weight %) Comparative Example 4 Comparative Example 5 Comparative Example 6 1. Propylene Glycol Total 100 Total 100 Total 100 2. Ceramide 10.0 10.0 10.0 3. Cholesterol 6.0 6.0 6.0 4. Cetostearyl Alcohol 4.0 4.0 4.0 5. PEG-15 Oleate 15.0 15.0 15.0 6. Retinol 3.0 10.0 15.0

[0056] 3. Preparation of Comparative Examples 7 to 9

[0057] An emulsion composition was prepared using a lamellar liquid crystal base containing retinol, prepared according to Table 2. According to the composition of Table 3 below, raw materials 1 to 7 were weighed into a beaker, heated to 72–75°C, and then uniformly mixed using a homomixer to prepare an oil phase. Separately, raw materials 8 to 14 were weighed into a beaker, heated to 72–75°C, and then uniformly mixed using a homomixer to prepare a water phase. Subsequently, the oil phase was slowly added to the water phase, and the mixture was emulsified at 6,000 rpm for 10 minutes while maintaining the temperature at 72–75°C. Then, the mixture was cooled to 45–50°C, the lamellar liquid crystal base (raw material 15) was added, and the mixture was further emulsified at 5,000 rpm for 5 minutes, followed by degassing and cooling to prepare a retinol cosmetic.

[0058] Ingredient Name (Weight%) Comparative Example 7 Comparative Example 8 Comparative Example 9 1 Cetostearyl Alcohol 1.0 1.0 1.02 Glyceryl Stearate 1.0 1.0 1.03 PEG-100 Stearate 1.0 1.0 1.04 Sorbitan Sesquistearate 1.5 1.5 1.55 Hexyldecyl Ethylhexanoate 5.0 5.0 5.06 Caprylic / Capric Glycerides 4.0 4.0 4.07 Triethylhexanoin 3.0 3.0 3.08 Purified Water to 100 to 100 to 1009 Dipropylene Glycol 10.010.010.010 Glycerin 8.08.08.011 Glycereth-265.05.05.012 Carbomer 0.10.10.113 Triethanolamine 0.10.10.114 Preservative appropriate amount appropriate amount appropriate amount 15 Lamellar Liquid Crystal Base 10 (Comparative Example 4) 10 (Comparative Example 5) 10 (Comparative Example 6)

[0059] <Test Example 1> Skin Irritation Evaluation 1: Human Occlusive Patch Evaluation

[0060] A human patch test was conducted to evaluate whether the retinol cosmetic formulations of Examples 1 to 3 and Comparative Examples 1 to 3 caused skin irritation. The evaluation was performed on 50 healthy adult men and women in accordance with the CTFA guidelines (The Cosmetic, Toility and Fragrance Association, Inc. Washington, DC, 20036, 1991). Specifically, 25 µl of the Example or Comparative Example was applied to a Finn Chamber, placed on the test site (the back of the human body), and secured with tape. After the patch was applied for 48 hours, the chamber was removed, and after another 2 hours had elapsed, the skin reaction at the test site was evaluated according to the following criteria. The skin irritation index was then calculated according to Equation 1, and the results are shown in Table 5.

[0061] [Assessment Criteria] Irritation Index Assessment Criteria - No erythema or specific phenomena ± Slightly redder than surroundings + Significantly redder than surroundings ++ Severely redder and swollen than surroundings

[0062] [Mathematical Formula 1] Stimulation Index = [{(±) number × 1} + {(+) number × 2} + {(++) number × 3}] ÷ Number of Test Subjects

[0063] Stimulation Index (STEM) Sample Subject Count Assessment Result + + + ± - Example 1 50 --- 500.00 Example 2 50 -- 4460.08 Example 3 50 -- 8420.16 Comparative Example 1 50 18410.20 Comparative Example 2 50 2515280.62 Comparative Example 3 50 5103051.30 Comparative Example 7 50 2612 -0.6 Comparative Example 8 50 151520 -1.9 Comparative Example 9 50 301010 -2.4

[0064] As shown in Table 5 above, in the case of Examples 1 to 3 according to the present invention, by using a cholesteric liquid crystal composition as a base and encapsulating retinol within a cholesteric liquid crystal layered structure, the amount of retinol released into the skin upon application was controlled. This significantly reduced irritation, confirming that it did not cause skin irritation. In particular, even when the retinol content was high at 1.0 weight% or more, the irritation index was evaluated to be 0.2 or lower, confirming that it was low-irritation. In contrast, as in Comparative Examples 1 to 3, it was confirmed that significant skin irritation occurred when a cholesteric liquid crystal composition was not used. Furthermore, it was confirmed that the O / W emulsion containing a lamellar liquid crystal base exhibited very high skin irritation compared to Comparative Examples 1 and 3, which were anhydrous oil formulations. From the above results, it was confirmed that using a cholesteric liquid crystal composition can demonstrate an effect of significantly improving skin irritation even when containing a high concentration of retinol.

[0065] <Test Example 2> Skin Irritation Evaluation 2: Cumulative Patch Evaluation

[0066] To more precisely compare and evaluate the skin irritation of Examples 1 and 2 and Comparative Examples 1 and 2, a Repeated Open Application Test was conducted on 20 adult men and women. Specifically, 25 mg of the sample was applied daily for 7 days to the fold of the inner elbow twice a day (9 a.m. and 7 p.m.), and the skin condition was checked before the application of the sample every morning.

[0067] The skin irritation test evaluated direct skin irritation by assigning a score of None / Doubtful / Weak / Moderate / Strong through visual evaluation by an expert.

[0068] The neurosensory irritation test was a method of confirming the probability of occurrence of sting, itching, and burning felt by subjects as sensors, with ≤ 0.3 : non-sting / itching, 0.3 < S ≤ 1.0 : slight sting / itching, 1.0 < S ≤ 2.0 : moderate sting / itching, and 2.0 < : severe sting / itching.

[0069] The visual skin irritation and nerve irritation levels over time were evaluated and are shown in Tables 6 and 7, respectively.

[0070] Sample Irritation test (Irritation index, Erythema, Edema, Papule, etc.) Day 1 Day 2 Day 3 Day 4 Day 7 Example 10.000.000.000.050.05 Example 20.000.050.080.050.08 Comparative Example 10.080.180.200.200.34 Comparative Example 20.180.220.400.550.60

[0071] Sample Neurosensory irritation test (Irritation Index) Day 1 Day 2 Day 3 Day 4 Day 7 Example 10.000.000.000.000.05 Example 20.050.000.000.050.05 Comparative Example 10.280.220.220.220.39 Comparative Example 20.280.300.400.550.65

[0072] As shown in Tables 6 and 7, when Examples 1 and 2 according to the present invention were used, there was no concern regarding irritation, and it was confirmed that they were less irritating compared to Comparative Examples 1 and 2 in both visual and sensory stimulation evaluations. From the above results, it was confirmed that the cosmetic composition of the present invention causes significantly less skin irritation even when retinol is used at a high concentration.

[0073] <Test Example 3> Wrinkle Improvement Evaluation

[0074] The wrinkle-improving effect of the present invention prepared according to Examples 1 and 2 above was evaluated. The evaluation was conducted on 30 adult women aged 45 to under 65. Specifically, the evaluators were instructed to apply the sample to the left and right nasolabial folds in the evening for 6 weeks. During the first 2 weeks, the samples were applied every other day, and from the 3rd week until the end of the evaluation, they were applied daily. At the same time, wrinkles were measured using Antera 3D every 2 weeks, and the overall size of the fine wrinkles of the nasolabial folds was calculated. The overall size of the fine wrinkles refers to the value obtained by dividing the total volume of the area with a lower height compared to the surface area during Antera measurement by the total area, and the wrinkle improvement rate (%) was calculated according to the following Equation 2 and is shown in Table 8.

[0075] [Mathematical Formula 2]

[0076] (Week 0 wrinkle overall size - Week 6 wrinkle overall size) ÷ (Week 0 wrinkle overall size) × 100

[0077] Sample Example 1 Example 2 Wrinkle Improvement Rate (%) 34.8 52.8

[0078] As confirmed in Table 8, it was confirmed that skin wrinkles were significantly improved when using a hypoallergenic cosmetic product of high-concentration retinol-containing cholesteric liquid crystal prepared according to the present invention.

[0079] Foregoing, specific parts of the present invention have been described in detail. It will be apparent to those skilled in the art that such specific descriptions are merely preferred embodiments and do not limit the scope of the invention. Accordingly, the actual scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A cholesteric liquid crystal composition comprising cholesteryl isostearate, cholesteryl nonanoate, cholesteryl chloride, and cholesteryl stearate; and Hypoallergenic cosmetic composition containing retinoids.

2. A low-irritation cosmetic composition according to claim 1, characterized in that the weight ratio of cholesteryl isostearate : cholesteryl nonanoate : cholesteryl chloride : cholesteryl stearate is 35~65 : 15~35 : 10~25 : 0.1~10, and the sum of each weight ratio satisfies 100.

3. A low-irritation cosmetic composition according to claim 1, characterized in that the cholesteric liquid crystal composition is included in an amount of 30 to 90 weight% based on the total weight of the cosmetic composition.

4. A low-irritation cosmetic composition according to claim 1, characterized in that the retinoid is included in an amount of 0.1 to 3 weight% based on the total weight of the cosmetic composition.

5. A low-irritation cosmetic composition according to claim 1, characterized in that the composition is anhydrous.

6. A hypoallergenic cosmetic composition according to claim 1, characterized in that the composition is for improving acne, pigmentation, keratinization, or wrinkles.

7. A cholesteric liquid crystal composition comprising cholesteryl isostearate, cholesteryl nonanoate, cholesteryl chloride, and cholesteryl stearate; and A hypoallergenic topical quasi-drug composition containing a retinoid.

8. A cholesteric liquid crystal composition comprising cholesteryl isostearate, cholesteryl nonanoate, cholesteryl chloride, and cholesteryl stearate; and A pharmaceutical composition for the treatment and prevention of skin diseases containing retinoids.

9. A pharmaceutical composition for the treatment and prevention of skin diseases, wherein, in paragraph 8, the skin disease is selected from the group consisting of acne and psoriasis.