Lamellar structure regeneration agent

Abstract

Disclosed is a novel lamellar structure regeneration agent for the stratum corneum. A lamellar structure regeneration agent according to the present invention contains hydrolyzed sericin as an active ingredient. The lamellar structure regeneration agent according to the present invention has the effect of regenerating a lamellar structure of intercellular lipids in the stratum corneum of the skin. The lamellar structure regeneration agent preferably further contains tocopheryl phosphate and / or a trisaccharide. The trisaccharide is preferably raffinose.

Description

Lamellar structure regenerator

[0001] The present invention relates to a lamellar structure regenerating agent, and more particularly to a lamellar structure regenerating agent that regenerates the lamellar structure of intercellular lipids in the stratum corneum.

[0002] The intercellular lipids in the stratum corneum exist in a lamellar structure, which is known to contribute to the skin's barrier function and stratum corneum's moisture retention mechanism. Therefore, the normal formation of lamellar structures in the stratum corneum is essential for maintaining skin moisture and stratum corneum flexibility.

[0003] As a technology focusing on regenerating the lamellar structure of intercellular lipids in the stratum corneum, for example, Japanese Patent Laid-Open Publication No. 2006-045186 (Patent Document 1) discloses a lamellar structure regenerating agent for skin stratum corneum cells containing glucose and / or raffinose, and a lamellar structure regenerating agent for skin stratum corneum cells containing glucose and oligosaccharides.

[0004] Sericin, a silk protein, contains many hydrophilic amino acids and has excellent biocompatibility, leading to its potential applications in food, cosmetics, pharmaceuticals, and other fields, with some applications already in practical use.

[0005] The present applicant has previously proposed a surfactant comprising sericin (JP 2008-221209 A (Patent Document 2)). Furthermore, the applicant has discovered that in a liquid crystal emulsification method, adding hydrolyzed sericin to a liquid crystal phase containing lecithin and a polyhydric alcohol in advance stabilizes a lamellar liquid crystal structure, and that applying a topical skin preparation having a lamellar liquid crystal structure to the skin improves the skin's barrier function (WO 2018 / 020903 (Patent Document 3)).

[0006] However, there is no description or suggestion of the effect of hydrolyzed sericin itself on the lamellar structure of stratum corneum intercellular lipids, specifically, the ability to regenerate the lamellar structure of stratum corneum intercellular lipids, without the hydrolyzed sericin itself necessarily being included in a composition having a lamellar structure.

[0007] JP 2006-045186 A JP 2008-221209 A International Publication No. 2018 / 020903

[0008] The present inventors have now discovered that hydrolyzed sericin has the ability to regenerate the lamellar structure of intercellular lipids in the stratum corneum (lamellar structure regeneration ability), and the present invention is based on this discovery.

[0009] Therefore, an object of the present invention is to provide a novel lamellar structure regenerating agent, as well as a novel use of hydrolyzed sericin and a method using the same.

[0010] The agent for regenerating the lamellar structure in the stratum corneum according to the present invention contains hydrolyzed sericin as an active ingredient.

[0011] The present invention also provides use of hydrolyzed sericin for regenerating the lamellar structure in the stratum corneum.

[0012] Furthermore, the present invention provides a method for regenerating the lamellar structure in the stratum corneum, which comprises applying the agent for regenerating the lamellar structure in the stratum corneum according to the present invention to skin.

[0013] 1 is a graph showing the effect of regenerating the lamellar structure of intercellular lipids in the stratum corneum. 2 is a graph showing the rate of change in stratum corneum moisture content. 3 is a graph showing the rate of change in transepidermal water loss.

[0014] Lamellar Structure Regenerating Agent The lamellar structure regenerating agent of the present invention has the effect of regenerating the lamellar structure. In the present invention, the term "regenerating the lamellar structure" is used to mean not only promoting the formation of a new lamellar structure but also acting on a state in which the lamellar structure has been lost or is about to be lost, thereby reconstructing the lamellar structure.

[0015] Furthermore, the lamellar structure regenerating agent of the present invention is not limited to lamellar structures in intercellular lipids of the stratum corneum in human skin, but can also be applied to lamellar structures in intercellular lipids similar to those of the stratum corneum in other organisms, and even in vitro. Therefore, in the present invention, the term "lamellar structure in the stratum corneum" is used to mean not only the lamellar structure in intercellular lipids of the stratum corneum in the skin of a living organism, but also the lamellar structure in intercellular lipids similar to those of the stratum corneum formed in vitro.

[0016] The mechanism by which the lamellar structure regenerating agent of the present invention regenerates the lamellar structure in the stratum corneum is unclear, but is thought to be as follows. However, the following explanation is merely a theoretical consideration, and the present invention is not limited to this mechanism. Hydrolyzed sericin has the ability to adsorb to the oil-water interface and functions as a hydrophilic surfactant. Because the lamellar structure of stratum corneum intercellular lipids is formed from lipid molecules primarily composed of ceramide and water, it is thought that hydrolyzed sericin, an amphiphilic substance, easily interacts with stratum corneum intercellular lipids. The hydrophilic portion of hydrolyzed sericin interacts with water and the hydrophilic groups of ceramide, and the hydrophobic portion of hydrolyzed sericin interacts with the hydrophobic groups of ceramide, thereby achieving the effect of regenerating the lamellar structure. Furthermore, it is thought that the hydrolyzed sericin is selectively positioned in the water layer of the lamellar structure of stratum corneum intercellular lipids, thereby regenerating the original lamellar structure.

[0017] Hydrolyzed Sericin The agent for regenerating a lamellar structure in the stratum corneum according to the present invention (hereinafter sometimes simply referred to as "lamellar structure regenerating agent") comprises hydrolyzed sericin as an active ingredient.

[0018] The hydrolyzed sericin used in the present invention is readily available as a hydrolyzate from silkworm cocoons, raw silk, or the like. For example, the hydrolyzed sericin used in the present invention can be obtained by partially hydrolyzing and eluting sericin from raw materials such as silkworm cocoons or raw silk using methods such as high-temperature, high-pressure water hydrolysis using water or physiological saline; acid hydrolysis using hydrochloric acid, sulfuric acid, or phosphoric acid; alkaline hydrolysis using sodium hydroxide or sodium carbonate; or enzymatic hydrolysis using microbial or plant-derived proteases. According to one aspect of the present invention, the hydrolyzed sericin obtained by the above method may be purified according to known protein separation and purification techniques to obtain a high-purity aqueous solution of sericin hydrolyzate, which can be used as the hydrolyzed sericin in the present invention. Furthermore, the hydrolyzed sericin may be dried to a solid by methods such as hot air drying, vacuum drying, or freeze-drying.

[0019] According to one preferred embodiment of the present invention, the hydrolyzed sericin contains 20 to 40 mol% serine as an amino acid composition. A serine content of 20 mol% or more allows the various functions and effects of sericin, particularly its moisturizing effect, to be fully achieved. The amino acid composition can be determined, for example, by post-column derivatization-fluorescence detection using a high-performance liquid chromatograph amino acid analysis system LC-10 (Shimadzu Corporation).

[0020] According to one preferred embodiment of the present invention, the weight-average molecular weight of the hydrolyzed sericin is preferably 3,000 to 45,000, and more preferably 10,000 to 30,000. A weight-average molecular weight of 3,000 or more facilitates the restoration of the lamellar structure of intercellular lipids in the stratum corneum. Furthermore, a weight-average molecular weight of 45,000 or less is advantageous in maintaining the stability of the lamellar structure restoration agent, preventing deterioration in handleability due to a decrease in the water solubility of the hydrolyzed sericin itself and precipitation of the hydrolyzed sericin over time. The weight-average molecular weight can be determined, for example, by GPC analysis using a high-performance liquid chromatograph CLASS-LC10 (Shimadzu Corporation).

[0021] The amount of hydrolyzed sericin contained in the lamellar structure regenerating agent according to the present invention is not particularly limited, and can be appropriately adjusted depending on the formulation of the lamellar structure regenerating agent and the composition ratio of other ingredients.

[0022] According to one aspect of the present invention, the amount of hydrolyzed sericin contained in the lamellar structure regenerating agent is preferably 0.001 to 5% by mass, and more preferably 0.1 to 5% by mass, based on the total amount of the lamellar structure regenerating agent. A content of 0.001% by mass or more efficiently achieves the effect of regenerating the lamellar structure of intercellular lipids in the stratum corneum. Furthermore, a content of 5% by mass or less can suppress stickiness of the lamellar structure regenerating agent, resulting in an excellent feel when used. Furthermore, by keeping the amount of hydrolyzed sericin within the above range, the effects of the stability over time of the lamellar structure regenerating agent and the ease of handling during preparation of the lamellar structure regenerating agent can be achieved.

[0023] The hydrolyzed sericin used in the present invention has an amino acid composition similar to that of natural moisturizing factors, and contains a high proportion of amino acids with hydroxyl groups and amino acids with carboxyl groups. Therefore, the lamellar structure regenerating agent of the present invention is highly hydrophilic, and is expected to have a high effect of improving the skin environment (moisture content) of the stratum corneum while also enhancing adhesion to the skin.

[0024] Tocopheryl Phosphate and Trisaccharides According to a preferred embodiment of the present invention, the lamellar structure regenerating agent further contains tocopheryl phosphate and / or trisaccharide. The inclusion of tocopheryl phosphate and / or trisaccharide enhances the effect of regenerating the lamellar structure of intercellular lipids in the stratum corneum. That is, according to this embodiment of the present invention, a synergistic effect between hydrolyzed sericin and tocopheryl phosphate and / or trisaccharide is exerted, specifically enhancing the effect of regenerating the lamellar structure of intercellular lipids in the stratum corneum. Furthermore, by enhancing the effect of regenerating the lamellar structure, it is possible to advantageously reduce the content of hydrolyzed sericin, tocopheryl phosphate, and / or trisaccharide. Furthermore, trisaccharides can sometimes impart stickiness to compositions containing them, but this can be reduced, thereby improving the feel of the lamellar structure regenerating agent when used. Furthermore, a low content of these components is advantageous from a cost perspective.

[0025] Tocopheryl phosphate, an amphiphilic substance, is thought to interact easily with intercellular lipids of the stratum corneum, similar to hydrolyzed sericin. Sodium tocopheryl phosphate, a tocopheryl phosphate, is an anionic amphiphilic substance with a different balance of hydrophilic and hydrophobic groups than hydrolyzed sericin. Therefore, it exhibits a different interaction with ceramides and water than hydrolyzed sericin. Therefore, the coexistence of hydrolyzed sericin and tocopheryl phosphate is thought to improve the effect of regenerating the lamellar structure. Furthermore, the hydrophilic properties of trisaccharides are thought to act primarily on the hydrophilic portions of water and hydrolyzed sericin, thereby assisting in the stabilization of the lamellar structure. Furthermore, the placement of hydrolyzed sericin and trisaccharides in the aqueous layer of the lamellar structure, and the placement of tocopheryl phosphate in the lipid layer of the lamellar structure, is thought to regenerate the lamellar structure inherent to the stratum corneum, consisting of an aqueous layer and a lipid layer. Note that these explanations of the mechanism of action are merely theoretical considerations and do not limit the scope of the present invention.

[0026] The tocopheryl phosphate used in the lamellar structure regenerating agent according to the present invention is not particularly limited, and examples include sodium salts, potassium salts, triethanolamine salts, etc. These tocopheryl phosphates can be used alone or in combination of two or more. According to a preferred embodiment of the present invention, the sodium salt is preferred from the viewpoint of a synergistic effect with hydrolyzed sericin. Commercially available tocopheryl phosphates can also be used, such as dl-α-tocopheryl phosphate sodium (product name: vitamin E sodium phosphate (TPNa)) from Resonac Co., Ltd. TPNa is a mixture of monosodium and disodium salts of dl-α-tocopheryl phosphate.

[0027] The amount of tocopheryl phosphate contained in the lamellar structure regenerating agent according to the present invention is not particularly limited and can be appropriately adjusted depending on the formulation of the lamellar structure regenerating agent and the composition ratio of other ingredients. According to one aspect of the present invention, the content of tocopheryl phosphate contained in the lamellar structure regenerating agent is preferably 0.0001 to 1 mass% and more preferably 0.001 to 0.1 mass% based on the total amount of the lamellar structure regenerating agent. One of the features of the present invention is that the effect of adding tocopheryl phosphate is achieved with such an extremely small amount. A content of 0.0001 mass% or more can enhance the effect of lamellar structure regeneration. A content of 1 mass% or less can particularly improve the stability over time of the lamellar structure regenerating agent.

[0028] The trisaccharide used in the lamellar structure regenerating agent of the present invention is not particularly limited, and examples thereof include raffinose, fucosyllactose, kestose, etc. These trisaccharides can be used alone or in combination of two or more. In a preferred embodiment of the present invention, raffinose is preferred from the viewpoint of synergistic effects with hydrolyzed sericin.

[0029] The amount of trisaccharide contained in the lamellar structure regenerator of the present invention is not particularly limited and can be adjusted appropriately depending on the formulation of the lamellar structure regenerator and the composition ratio of other ingredients. According to one aspect of the present invention, the content of trisaccharide contained in the lamellar structure regenerator is preferably 0.00001 to 2% by mass, more preferably 0.00005 to 1% by mass, and even more preferably 0.0001 to 1% by mass, based on the total amount of the lamellar structure regenerator. The fact that the effect of adding trisaccharide is achieved with such an extremely small amount is one of the features of the present invention. A content of 0.00001% by mass or more can enhance the effect of lamellar structure regeneration. A content of 2% by mass or less can improve the stability of the lamellar structure regenerator over time. Furthermore, by setting the amount of trisaccharide within the above range, the stickiness of the lamellar structure regenerator can be suppressed, resulting in an excellent feel when used.

[0030] According to a preferred embodiment of the present invention, when the lamellar structure regenerating agent of the present invention contains hydrolyzed sericin and tocopheryl phosphate, the mass ratio thereof is in the range of 1:0.001-1, preferably 1:0.01-1; when the agent contains hydrolyzed sericin and trisaccharide, the mass ratio thereof is in the range of 1:0.0005-200, preferably 1:0.0005-100; and when the agent contains hydrolyzed sericin, tocopheryl phosphate, and trisaccharide, the mass ratio thereof is in the range of 1:0.001-1:0.0005-200, preferably 1:0.01-1:0.0005-100, thereby enabling the synergistic effect of these components to be more effectively exerted.

[0031] Other Components The lamellar structure regenerating agent according to the present invention may be appropriately blended with oils, moisturizers, UV absorbers, emulsifiers, thickeners, surfactants, chelating agents, oily components, polyhydric alcohols, alcohols, thickeners, colorants, vitamins, antioxidants, anti-inflammatory agents, pH adjusters, antibacterial agents, preservatives, extracts derived from animals, plants, fish and shellfish, or microorganisms, fragrances, etc., as needed, within the scope that does not impair the effects of the present invention.

[0032] By adding the various components described above to the lamellar structure regenerating agent of the present invention, it is expected that the agent will provide effects such as moisturizing, cell activation, anti-aging, and rough skin improvement, depending on the components.

[0033] The lamellar structure regenerating agent of the present invention can be used as is, or can be added to other compositions as an additive for regenerating the lamellar structure of intercellular lipids. Therefore, the lamellar structure regenerating agent of the present invention may be provided as a topical skin preparation, cosmetic, quasi-drug, or pharmaceutical product for the purpose of regenerating the lamellar structure of intercellular lipids. According to one aspect of the present invention, cosmetics, quasi-drugs, pharmaceutical products, etc. are preferred, with cosmetics and quasi-drugs being more preferred due to their everyday use, and skin care cosmetics and makeup cosmetics being even more preferred. Furthermore, the formulation of the agent is not particularly limited as long as it does not impair the effects of the present invention, and may be appropriately selected from, for example, lotions, serums, emulsions, creams, gels, packs, sprays, roll-on products, sticks, soaps, sheets, mousses, ointments, foundations, lip balms, bath additives, hair tonics, soaps, facial cleansers, body shampoos, etc.

[0034] Another aspect of the present invention provides a use of hydrolyzed sericin for regenerating lamellar structure in the stratum corneum. Furthermore, as described above, hydrolyzed sericin can be used in combination with tocopheryl phosphate and / or a trisaccharide. Therefore, the present invention provides a use of hydrolyzed sericin in combination with tocopheryl phosphate and / or a trisaccharide. In this aspect, the trisaccharide is preferably raffinose.

[0035] Another aspect of the present invention provides a method for regenerating the lamellar structure in the stratum corneum, comprising applying the lamellar structure regenerating agent of the present invention to skin. Furthermore, as described above, hydrolyzed sericin can be used in combination with tocopheryl phosphate and / or a trisaccharide, and therefore a method for regenerating the lamellar structure in the stratum corneum in combination with tocopheryl phosphate and / or a trisaccharide is also provided. In this aspect, the trisaccharide is preferably raffinose.

[0036] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to the following examples.

[0037] Preparation of Materials In this example, hydrolyzed sericin, ceramide mix, and cholesterol mix prepared by the following methods were used.

[0038] Preparation of Hydrolyzed Sericin: Pupae were removed from cocoons of domesticated silkworms (Bombyx mori), and distilled water was added in an amount 15 times the mass of the cocoons. Hydrolyzed sericin was extracted under conditions of 0.3 MPa, 134°C, and extraction time of 120 minutes. The resulting extract was filtered through a membrane filter with a pore size of 0.2 μm to obtain a purified solution. The purified solution was then freeze-dried to obtain hydrolyzed sericin powder. The weight-average molecular weight of the resulting hydrolyzed sericin was 16,000. The serine content was 32.5%.

[0039] Preparation of Ceramide Mix Ceramide NDS (Ceramide TIC-001, manufactured by Takasago International Corporation), ceramide NP (DS-Ceramide YO, manufactured by Doosan Corporation), and ceramide AP (DS-Ceramide AP, manufactured by Doosan Corporation) were mixed in a mass ratio of 1:1:1 and homogenized.

[0040] Preparation of cholesterol mix Stearic acid (stearic acid, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.), cholesterol (cholesterol, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.), and cholesterol sulfate (cholesteryl sodium sulfate, manufactured by Combi-Blocks) were mixed in a mass ratio of 4:4:1 and homogenized.

[0041] Other materials: Sodium tocopheryl phosphate (tocopheryl phosphate, trade name "Vitamin E Sodium Phosphate (TPNa)", manufactured by Resonac Co., Ltd.) Raffinose (trisaccharide, trade name "Oligo GGF", manufactured by Asahi Kasei Finechem Co., Ltd.) Kestose (trisaccharide, trade name "1-kestose", manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.)

[0042] Evaluation of Lamellar Structure Regeneration Ability (In Vitro) Examples 1 to 14, 16 to 43 and Comparative Example 1: Preparation of Evaluation Samples Ceramide mix, cholesterol mix, water, hydrolyzed sericin, tocopheryl phosphate, and trisaccharide were added in the amounts shown in Tables 1 to 5 below, and mixed at room temperature for 2 minutes. After heating for 5 minutes in an 80°C thermostatic bath, the mixture was mixed at room temperature for 2 minutes, ultrasonicated at room temperature for 1 minute, and heated again in an 80°C thermostatic bath for 120 minutes to obtain evaluation samples for Examples 1 to 14, 16 to 43, and Comparative Example 1. The unit of blend amounts in the tables is "% by mass." The "remaining amount" of water indicates the amount necessary to bring the total to 100% by mass.

[0043] Observation and Analysis: The specimen to be evaluated was placed on a glass slide, spread evenly with a cover glass, and observed with polarized light at 400x magnification using an upright microscope (System Biological Microscope BX53, manufactured by Olympus Corporation). Five areas were selected to capture images, avoiding any foreign matter other than the maltase cross image (synonymous with lamellar structure). Each image area was 90 mm. ２ 16mm ２ The area was randomly selected, and the number of maltase cross images within this area was visually counted. The number of maltase cross images was counted in the same manner for five imaged locations, and the average of the obtained values ​​was calculated. The control was a sample containing no hydrolyzed sericin, tocopheryl phosphate, or trisaccharide. The lamellar structure regeneration ability was evaluated using the change in the number of maltase cross images relative to the average number of maltase cross images in the control (Comparative Example 1). A change rate of 1.2 or higher was determined to be effective in regenerating the lamellar structure of stratum corneum intercellular lipids (i.e., lamellar structure regeneration ability). The results are shown in the table below.

[0044]

[0045]

[0046]

[0047]

[0048]

[0049] As is clear from the table, the lamellar structure regeneration rate of hydrolyzed sericin was 1.22 times higher at a low concentration of 0.001% by mass, 1.54 times higher at 0.1% by mass, 2.02 times higher at 1.0% by mass, and 2.14 times higher at 5.0% by mass compared to Comparative Example 1. This confirms that hydrolyzed sericin has the effect of regenerating the lamellar structure of intercellular lipids in the stratum corneum (i.e., lamellar structure regeneration ability). Furthermore, as is clear from the table, the incorporation of tocopheryl phosphate and / or trisaccharide in addition to hydrolyzed sericin produced a synergistic effect on the effect of regenerating the lamellar structure of intercellular lipids in the stratum corneum (i.e., lamellar structure regeneration ability) (Examples 1-2, 7-14, and 16-43).

[0050] Evaluation of lamellar structure regeneration ability (in vivo) First, the lotions of Example 15 and Comparative Example 2 were prepared as follows. Specifically, the components shown in Table 6 were added in the amounts shown, and mixed at room temperature until uniform. Five female volunteers with healthy skin were used as subjects, and an artificial rough skin condition was created on the inner forearm using a 5% SDS aqueous solution. The lotion of Example 15 or Comparative Example 2 was applied to the rough skin area for seven days. The stratum corneum condition (lamellar liquid crystal) was observed in the initial state (before rough skin was created) and seven days after the start of continuous application. An untreated area (no rough skin was created and no lotion was applied) served as a control. The unit of blend amounts in Table 6 is "% by mass." The "remaining amount" of water indicates the amount necessary to make the total 100% by mass.

[0051]

[0052] The stratum corneum condition was observed as follows. The stratum corneum was sampled using a keratin sampling sticker (manufactured by Moritex Corporation). Five randomly selected locations were observed under coaxial epi-illumination at 500x magnification using a microscope (digital microscope VHX-800, manufactured by Keyence Corporation). The images were then digitized using image analysis software (Image J, National Institutes of Health (NIH)) to calculate the area of ​​the lamellar liquid crystals. The areas of the five imaged locations were calculated in the same manner, and the average of the resulting areas was calculated. The lamellar structure regeneration rate was evaluated using the amount of change in the area of ​​the maltase cross image relative to the initial state (before rough skin was created). A change rate of 1.2 or higher was considered to be effective in regenerating the lamellar structure of the stratum corneum intercellular lipids (i.e., lamellar structure regeneration ability).

[0053] The results are shown in Figure 1 and Table 6. As is clear from Figure 1 and Table 6, the control was a site where no rough skin was created and no lotion was applied continuously, and the condition of the stratum corneum after 7 days was almost the same (see "Control" in Figure 1). On the other hand, in the site where the lotion of Comparative Example 2 was applied continuously to the rough skin condition, the lamellar liquid crystal area decreased by about 0.8 times (see "Comparative Example 2" in Figure 1). In contrast, in the site where the lotion of Example 15 was applied continuously to the rough skin condition, the lamellar liquid crystal area increased by about 2.7 times (see "Example 15" in Figure 1). This confirmed that, although the lamellar liquid crystal structure is disrupted in a rough skin condition, the lamellar liquid crystal structure was restored by continuous application of the lotion of Example 15. Furthermore, the effect was able to lead to a skin condition superior to that of the control.

[0054] Evaluation of Barrier Function Recovery Five female volunteers with healthy skin were subjected to artificial rough skin treatment on the inner forearm using a 5% SDS aqueous solution. The lotions of Example 15 and Comparative Example 2 shown in Table 6 were applied to the rough skin areas for 10 days. The stratum corneum moisture content (SKICON-200, manufactured by I.B.S.) and transepidermal water loss (Tewameter™ Hex, manufactured by Courage+Khazaka) were measured at the initial state (before rough skin was created), before continuous use (immediately after rough skin was created, also referred to as day 0 of continuous use), and after 4, 7, and 10 days of continuous use to evaluate the recovery of the skin's barrier function. An untreated area (without rough skin creation or continuous use of lotion) served as a control. The stratum corneum moisture content and transepidermal water loss were evaluated using the change from the values ​​before continuous use (immediately after rough skin creation, day 0 of continuous use) as indicators.

[0055] The results are shown in Figures 2 and 3. As is clear from Figures 2 and 3, the rough skin condition in the area where Example 15 was applied continuously was confirmed to have recovered barrier function over time. The moisture content of the stratum corneum increased with the continuous use of the lotions of Example 15 and Comparative Example 2. After 10 days of continuous use, the moisture content of the stratum corneum was approximately 1.6 times higher when the lotion of Example 15 was applied continuously than when the lotion of Comparative Example 2 was applied continuously (Figure 2). The amount of transepidermal water loss tended to decrease in the area where the lotion of Example 15 was applied continuously. After 10 days of continuous use, the amount of transepidermal water loss was approximately 0.9 times higher when the lotion of Example 15 was applied continuously than when the lotion of Comparative Example 2 was applied continuously. On the other hand, there was almost no change in the areas where the control and lotions of Comparative Example 2 were applied continuously (Figure 3).

Claims

1. A lamellar structure regeneration agent for the stratum corneum containing hydrolyzed sericin as the active ingredient.

2. The lamellar structure regenerating agent according to claim 1, further comprising tocopheryl phosphate and / or trisaccharide.

3. The lamellar structure regenerating agent according to claim 2, wherein the trisaccharide is raffinose.

4. A lamellar structure regenerating agent according to claim 2 or 3, which contains hydrolyzed sericin and tocopheryl phosphate in a mass ratio of 1:0.001-1, or hydrolyzed sericin and trisaccharide in a mass ratio of 1:0.0005-200, or hydrolyzed sericin, tocopheryl phosphate and trisaccharide in a mass ratio of 1:0.001-1:0.0005-200.

5. Use of hydrolyzed sericin for regenerating lamellar structure in the stratum corneum.

6. The use according to claim 4 in combination with tocopheryl phosphate and / or trisaccharides.

7. The use according to claim 5, wherein the trisaccharide is raffinose.

8. The use according to claim 6 or 7, wherein hydrolyzed sericin and tocopheryl phosphate are combined in a mass ratio of 1:0.001-1, hydrolyzed sericin and a trisaccharide are combined in a mass ratio of 1:0.0005-200, or hydrolyzed sericin, tocopheryl phosphate and a trisaccharide are combined in a mass ratio of 1:0.001-1:0.0005-200.

9. An external skin preparation or cosmetic comprising the lamellar structure regenerating agent according to any one of claims 1 to 4.

10. A method for regenerating the lamellar structure in the stratum corneum, comprising applying the lamellar structure regenerating agent according to any one of claims 1 to 4 to the skin.

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