Cosmetic material

Abstract

The present invention addresses the problem of obtaining a cosmetic material in which an active ingredient exhibits high skin permeability. Provided as a solution to the problem is a cosmetic material containing: (A) water; (B) hydrogenated lecithin; (C) a polyhydric alcohol; (D) a liposome that contains hydrolyzed collagen; and (E) at least one compound selected from niacinamide, tranexamic acid, and ε-aminocaproic acid.

Description

Cosmetics

[0001] This invention relates to a cosmetic composition containing liposomes.

[0002] A liposome is a capsule structure consisting of one or more layers of a lipid bilayer made of phospholipids. Phospholipid molecules have a pine needle-like shape and possess two properties: the phosphate portion is hydrophilic and the fatty acid ester portion is hydrophobic. When released into water, the hydrophobic portion gathers inward and the hydrophilic portion faces outward, forming a lipid bilayer and creating a spherical liposome. Liposomes can encapsulate water-soluble active ingredients in their hydrophilic portion and oil-soluble active ingredients in their hydrophobic portion. Liposomes are generally about 100-300 nm (0.1-0.3 μm) in size, and because they are nano-sized particles, it is known that the components held in liposomes have improved skin penetration. In addition, they have a superior feel, so they are widely used to improve the effectiveness and usability of topical skin preparations.

[0003] The inventors of the present invention have been continuing their research on liposomes. For example, in Patent Document 1 (Japanese Patent Application Laid-Open No. 2022-177701), a liposome dispersion containing (A) water, (B) hydrogenated lecithin, (C) butylene glycol, (D) hydrolyzed collagen, and (E) pentylene glycol coexisting in the composition, and a cosmetic containing this dispersion are described as having both a preservative effect against microorganisms and excellent stability in which liposomes do not break even after long-term storage. Specifically, the liposome is prepared with (A) to (D) first, and then pentylene glycol is added to the liposome dispersion in which the liposome is dispersed, so that not only the antiseptic effect against microorganisms is exhibited, but also the lipid bilayer does not break during long-term storage, thus exhibiting an excellent effect in terms of stability. On the other hand, in a conventional liposome, that is, a general liposome that does not contain (D) hydrolyzed collagen in the liposome composition, even when prepared in the same manner as above, during storage, the hydrophobic part of (E) pentylene glycol is incorporated into the lipid bilayer of the liposome, causing the liposome to become unstable and eventually collapse. That is, a preservative effect against microorganisms can be obtained, but the liposome breaks after long-term storage. And it is well-known to cosmetic formulators that in a conventional general liposome that does not contain (D) hydrolyzed collagen in the liposome composition, the liposome breaks during long-term storage.

[0004] The inventors of the present invention have been promoting the development of liposomes carrying hydrolyzed collagen and cosmetics containing the same. However, when the liposome is combined with a specific active ingredient (one or more selected from (E) niacinamide, tranexamic acid, and ε-aminocaproic acid), it has been found that the permeability of the active ingredient is significantly higher compared to the case where the liposome is not formulated.

[0005] Japanese Patent Application Laid-Open No. 2022-177701

[0006] An object of the present invention is to obtain a cosmetic with high skin permeability of an active ingredient.

[0007] The present invention relates to a cosmetic composition comprising liposomes formed from (A) water, (B) hydrogenated lecithin, (C) polyhydric alcohol, and (D) hydrolyzed collagen, and (E) one or more selected from niacinamide, tranexamic acid, and ε-aminocaproic acid. (A) Water is a dispersion medium when preparing liposomes, but is also encapsulated inside the liposomes. (C) Polyhydric alcohol plays a role as a solvent for (B) hydrogenated lecithin and as a preservative for the composition, and is present both inside and outside the liposomes. (D) Hydrolyzed collagen is mostly supported on the membrane of the liposomes. (E) Niacinamide, tranexamic acid, and ε-aminocaproic acid are hydrophilic active ingredients, and it is thought that most of them are attached to the outer membrane of the liposomes by hydrogen bonds. This configuration enhances the penetration of component (E) into the skin. Note that while the presence of component (E) in the inner phase of the liposome is not required, this does not preclude its presence in the inner phase of the liposome.

[0008] The main means for solving the problems of the present invention are as follows: (1) A cosmetic composition characterized by comprising (A) water, (B) hydrogenated lecithin, (C) polyhydric alcohol, (D) liposomes containing hydrolyzed collagen, and (E) one or more selected from niacinamide, tranexamic acid, and ε-aminocaproic acid. (2) The cosmetic composition according to (1), characterized in that (C) polyhydric alcohol comprises one or more selected from butylene glycol, pentylene glycol, dipropylene glycol, octanediol, hexanediol, glycerin, and diglycerin. (3) The cosmetic composition according to (1) or (2), characterized in that the mass ratio of component (B) to component (D) is 5:1 to 1:1. (4) The cosmetic composition according to any one of (1) to (3), characterized in that the content of a skin penetration inhibitor is 1% by mass or less of the total amount of the cosmetic composition. (5) A cosmetic composition according to any one of (1) to (4), characterized in that the phosphatidylcholine content of component (B) is 86% by mass or more. In this invention, the notation "A to B" (where A and B are numerical values ​​or ratios) means a numerical range that includes both ends.

[0009] By simply adding an appropriate amount of a dispersion containing liposome particles (liposome dispersion; A+B+C+D) to a cosmetic composition containing one or more specific active ingredients (E) selected from niacinamide, tranexamic acid, and ε-aminocaproic acid, a cosmetic composition with enhanced permeability of ingredient (E) is obtained. Similarly, by adding one or more specific active ingredients selected from (E) niacinamide, tranexamic acid, and ε-aminocaproic acid to the liposome dispersion (A+B+C+D), a cosmetic composition is obtained with enhanced permeability of ingredient (E). The high permeability of ingredient (E) in the cosmetic composition of the present invention is equivalent to that when ingredient (E) is encapsulated in liposomes. The liposomes used in the present invention, which contain (A) water, (B) hydrogenated lecithin, (C) polyhydric alcohol, and (D) hydrolyzed collagen, do not destabilize the liposome particles (the particle size changes over time and eventually breaks down), so they can be stored for long periods as raw materials for cosmetics and topical skin preparations. Therefore, in the present invention, there is no need to create separate liposomes for each component (E), and a long-term storable liposome dispersion can be combined with the necessary component (E) to form a cosmetic, thus significantly reducing manufacturing costs.

[0010] Evaluation of skin penetration of tranexamic acid contained in the cosmetics of Reference Example 1, Example 1, and Comparative Examples 1-3; graph showing the measurement results of Raman light intensity derived from tranexamic acid. Evaluation of penetration of niacinamide contained in the cosmetics of Example 2 and Comparative Example 4; graph showing the measurement results of Raman light intensity derived from niacinamide. Evaluation of penetration of ε-aminocaproic acid contained in the cosmetics of Example 3 and Comparative Example 5; graph showing the measurement results of Raman light intensity derived from ε-aminocaproic acid.

[0011] "Liposomes" The liposomes used in this invention contain (A) water, (B) hydrogenated lecithin, (C) polyhydric alcohol, and (D) hydrolyzed collagen. The liposomes used in this invention may be called collagen liposomes. During liposome preparation, some of (A) water and (C) polyhydric alcohol are encapsulated in the liposomes, but the majority becomes a dispersion medium. Therefore, in this invention, the amount of liposome particles in the liposome dispersion may be considered to be the total amount of (B) hydrogenated lecithin and (D) hydrolyzed collagen.

[0012] "Cosmetics" The cosmetics of the present invention contain collagen liposomes containing (A) to (D), along with one or more specific active ingredients (E) selected from niacinamide, tranexamic acid, and ε-aminocaproic acid. The cosmetics of the present invention include quasi-drugs, topical skin preparations, topical scalp preparations, penetrating cosmetics (cosmetics that claim high penetration of active ingredients), and penetrating compositions for the skin or scalp.

[0013] "Skin Penetration Inhibiting Components" When a product is intended to emphasize the penetration of active ingredients (quasi-drug, penetrating cosmetic, penetrating composition for skin or scalp), it is preferable that the cosmetic composition of the present invention contains a small amount of skin penetration inhibiting components that may form a film on the skin or scalp and inhibit the penetration of liposomes into the skin. Specifically, examples of skin penetration inhibiting components that may form a film and inhibit skin penetration include polyvinylpyrrolidone, polyvinyl alcohol, polyvinylimidazole-polyvinylpyrrolidone copolymer, and (VP / VA) copolymer. If skin penetration inhibiting components are included in amounts exceeding, for example, 1% by mass of the total amount of the cosmetic composition, they may form a film on the skin or scalp, potentially impairing the penetration of (E) niacinamide, tranexamic acid, and ε-aminocaproic acid into the skin and scalp. Therefore, if the cosmetic composition contains an optional component that inhibits skin penetration, it is preferable that the content of the skin penetration inhibitor relative to the total amount of the cosmetic composition be 1% by mass or less, more preferably 0.1% by mass or less, even more preferably 0.01% by mass or less, and most preferably not contain any component (0% by mass).

[0014] First, the components (A to D) used in the preparation of collagen liposomes will be explained. (A) Water Water is essential when preparing liposomes, and purified water, deionized water, pure water, etc. can be used. It is preferable that the amount of water be 50% by mass or more, and more preferable that it be 70% by mass or more, when preparing liposomes. After liposome preparation, the liposome particles are dispersed in a mixed solvent of water and polyhydric alcohol. This state is also called liposome dispersion (A + B + C + D).

[0015] (B) Hydrogenated lecithin Hydrogenated lecithin is a phospholipid and is the main component of the lipid bilayer of liposomes. Examples of hydrogenated lecithin include hydrogenated lecithin obtained by hydrogenating some or all of the unsaturated carbon chains in natural lecithin such as egg yolk lecithin or soy lecithin to saturated bonds, or hydrogenated synthetic phosphatidylcholine. One or more types of hydrogenated lecithin can be used. Among these, hydrogenated soy lecithin derived from soy lecithin is preferred. The amount of hydrogenated lecithin blended is preferably 0.01 to 5% by mass, and more preferably 0.1 to 3% by mass, based on 100% by mass of the liposome dispersion of the present invention.

[0016] Commercially available hydrogenated lecithin products include Nikko Chemicals' Resinol S-10M (phosphatidylcholine content 55-65% by mass), Resinol S-10E (phosphatidylcholine content 75-85% by mass), Tsuji Oil Co., Ltd.'s SLP-PC70HS (phosphatidylcholine content 65-75% by mass), SLP-PC92H (phosphatidylcholine content 90% or more by mass), Nisshin Oillio Ltd.'s Basis LP-60HR (phosphatidylcholine content 65-75% by mass), Nippon Oil & Fats Co., Ltd.'s COATSOME NC-61 (phosphatidylcholine content 60% or more by mass), and Kewpie Corporation's Egg Yolk Lecithin PL100P (phosphatidylcholine content approximately 80% by mass). In the present invention, from the viewpoint of the skin penetration of component (E), it is preferable that the content of phosphatidylcholine in (B) hydrogenated lecithin be 86% by mass or more, and more preferably 90% by mass or more. Furthermore, other phospholipids such as unhydrogenated lecithin, phosphatidylethanolamine, phosphatidylserine, phosphatidic acid, phosphatidylinositol, and phosphatidylglycerol may be used in combination, to the extent that they do not hinder the effects of the present invention. For example, other phospholipids may be used in combination at a concentration of 10% by mass or less of hydrogenated lecithin.

[0017] (C) Polyhydric alcohols Examples of polyhydric alcohols used in the present invention include butylene glycol, dipropylene glycol, pentylene glycol, octanediol, hexanediol, glycerin, and diglycerin. (C) Polyhydric alcohols serve as a solvent for (B) hydrogenated lecithin and can also impart antibacterial properties to the liposome dispersion. It is preferable to contain one or more polyhydric alcohols that serve as a solvent, and it is even more preferable to contain one or more polyhydric alcohols that impart antibacterial properties.

[0018] (Polyhydric alcohols used as solvents) Butylene glycol and dipropylene glycol are preferred when used as solvents for (B) hydrogenated lecithin in the preparation of liposome dispersions because they improve the solubility of hydrogenated lecithin. Butylene glycol and / or dipropylene glycol are preferably contained in amounts of 2 to 8 parts by mass, and more preferably in amounts of 3 to 7 parts by mass, per 1 part by mass of (B) hydrogenated lecithin.

[0019] (Polyhydric alcohols that impart antibacterial properties) Pentylene glycol, octanediol, and hexanediol are preferable to include as they improve the preservative efficacy (antibacterial properties) of the liposome dispersion of the present invention against microorganisms. In the present invention, good preservative efficacy is judged to be achieved if bacteria and yeasts meet the criteria described in Criteria A of the ISO preservative standards, and molds do not exceed the initial number of fungi after 28 days. When pentylene glycol, octanediol, and hexanediol are included, it is preferable to include them after liposome formation. From the viewpoint of preservative efficacy against microorganisms, the total amount of pentylene glycol, octanediol, and hexanediol is preferably 2.5% by mass or more, and more preferably 3% by mass or more, based on 100% by mass of the liposome dispersion of the present invention. The total amount of pentylene glycol, octanediol, and hexanediol is preferably 2.5 to 10% by mass, and more preferably 2.5 to 5% by mass, based on 100% by mass of the liposome dispersion of the present invention.

[0020] If other antibacterial components (such as parabens or phenoxyethanol) are included in the cosmetic, it is not necessary to include pentylene glycol, octanediol, and hexanediol in the liposome preparation for preservative purposes. Also, if the liposome dispersion is prepared and incorporated directly into the cosmetic without long-term storage, it is sufficient to preservative the final cosmetic product, so it is not necessary to include pentylene glycol, octanediol, and hexanediol in the liposome preparation for preservative purposes. (Polyhydric alcohols that impart moisturizing properties) Glycerin and diglycerin are highly moisturizing ingredients and primarily exert moisturizing effects. If only component (E) is added to the liposome dispersion to make a cosmetic, it is convenient to include glycerin and diglycerin in the liposome dispersion beforehand to save time during preparation. The polyhydric alcohol (C) is preferably 2 to 40% by mass, and more preferably 5 to 20% by mass, of the total amount of component (C) per 100% by mass of the liposome dispersion.

[0021] (D) Hydrolyzed Collagen Hydrolyzed collagen improves the storage stability of liposome particles. Hydrolyzed collagen is incorporated into the bilayer membrane of liposomes and contributes to the storage stability of liposomes. The inventors define liposome destabilization as the average particle size of liposomes measured before and after storage at 5, 25, and 40°C for two months, and calculating the rate of change, where any of these exceeds ±20%. By incorporating hydrolyzed collagen during liposome preparation, collagen liposomes with a strong membrane and stable particle size can be obtained. In this specification, particle size refers to the median diameter and can be measured by known methods, such as dynamic light scattering. Collagen liposomes containing hydrolyzed collagen can suppress changes in the particle size of liposomes over time and prevent them from eventually breaking down, even if components that destabilize liposomes (such as pentylene glycol) are included in the cosmetic.

[0022] Hydrolyzed collagen is a hydrolyzed product of collagen or gelatin. The hydrolyzed collagen of the present invention can be used without particular limitations as long as it is generally incorporated into cosmetics, and examples of its origins include animals such as pigs, cattle, and birds, as well as fish, shellfish, jellyfish, and sponges. However, from the viewpoint of odor, productivity, and economics, collagen derived from marine organisms is preferred. The method of hydrolysis is not particularly limited and may be hydrolysis by hydrolytic enzymes, hydrolysis by acid or alkali, or hydrolysis by microbial fermentation. The hydrolyzed collagen used in the present invention is preferably low molecular weight, and specifically, its weight-average molecular weight is preferably 400 to 1200. Furthermore, the hydrolyzed collagen used in the present invention is preferably one that contains 20% by mass or more of tripeptides. Examples of commercially available products include CTP-F60 (weight-average molecular weight 500, tripeptide content ≥ 55%), CTP-F (weight-average molecular weight 1000, tripeptide content ≥ 25%), CTP-S (weight-average molecular weight 1000, tripeptide content ≥ 25%), and CTP-M30 (weight-average molecular weight 1000, tripeptide content ≥ 25%), all manufactured by ZELICE Co., Ltd.

[0023] From the viewpoint of storage stability of liposome particles, the hydrolyzed collagen content is preferably 0.2 to 1 part by mass per 1 part by mass of hydrogenated lecithin (B). The mass ratio (B:D) of component (B) to component (D) is preferably 5:1 to 1:1, and more preferably 3:1 to 1:1.

[0024] Next, we will explain the essential component (E) that must be included when the product is made into a cosmetic. (E) One or more selected from niacinamide, tranexamic acid, and ε-aminocaproic acid. The present invention is a cosmetic made by mixing separately prepared liposomes (which may be liposome dispersions or liposome particles obtained by removing the dispersion medium from the liposome dispersion) with (E) one or more selected from niacinamide, tranexamic acid, and ε-aminocaproic acid. Niacinamide, tranexamic acid, and ε-aminocaproic acid may be any of those that can be incorporated into a cosmetic.

[0025] Niacinamide, also known as nicotinamide, niacin, or vitamin B3, is an amide compound of nicotinic acid. Niacinamide is a water-soluble vitamin and one of the B vitamins. A deficiency in niacinamide can lead to deficiency diseases such as pellagra. Niacinamide is used as an ingredient in topical medications to treat acne (acne vulgaris) and is also incorporated into cosmetics for cosmetic purposes. In Japan, it is approved as an active ingredient for wrinkle improvement (wrinkle niacin) and as an active ingredient for whitening (nicotinamide) in quasi-drug cosmetics. The amount of niacinamide included as component (E) is preferably 3 to 8% by mass of the total amount of cosmetic. To improve permeability, it is preferable to include approximately 0.5 to 1.5 parts by mass of the liposome particles of the present invention per 1 part by mass of niacinamide.

[0026] Tranexamic acid is a type of artificially synthesized amino acid that has the function of inhibiting the action of plasmin, which causes inflammation and allergies. Due to this effect, it is known to improve skin condition and is favored for inclusion in cosmetics. In recent years, its use for wrinkle improvement has also been increasing. The amount of tranexamic acid included as component (E) is preferably 0.5 to 5% by mass, more preferably 0.5 to 3% by mass, of the total amount of cosmetic. To improve permeability, it is preferable to include approximately 1 to 5 parts by mass of the liposome particles of the present invention per 1 part by mass of tranexamic acid.

[0027] ε-aminocaproic acid is an artificially synthesized neutral amino acid that has anti-inflammatory properties. The amount of ε-aminocaproic acid included as component (E) is preferably 0.005 to 2% by mass, more preferably 0.01 to 1% by mass, and even more preferably 0.05 to 0.5% by mass, based on the total amount of the cosmetic. To improve permeability, it is preferable to include approximately 1 to 5 parts by mass of the liposome particles of the present invention per 1 part by mass of ε-aminocaproic acid.

[0028] The proven concentrations of active ingredients in quasi-drugs vary depending on the type of cosmetic product. For example, in the case of lotion, the concentrations are 5% by mass for niacinamide, 2% by mass for tranexamic acid, and 0.1% by mass for ε-aminocaproic acid, relative to the total amount of the cosmetic product.

[0029] In the present invention, the amount of liposome particles in the liposome dispersion can be considered, although approximate, as the total amount of (B) hydrogenated lecithin and (D) hydrolyzed collagen. In particular, if you want to create a cosmetic (quasi-drug, penetrating cosmetic) that exhibits even greater permeability of the active ingredient, the formulation should be designed as follows. The cosmetic of the present invention is a cosmetic obtained by mixing liposomes containing (A) water, (B) hydrogenated lecithin, (C) polyhydric alcohol, and (D) hydrolyzed collagen with one or more selected from (E) niacinamide, tranexamic acid, and ε-aminocaproic acid. The cosmetic of the present invention may be either a cosmetic obtained by adding component (E) to separately prepared liposomes (collagen liposomes), or a cosmetic obtained by adding separately prepared liposomes (collagen liposomes) to a cosmetic containing component (E).

[0030] In the case of (E) niacinamide, when the total amount of (B) hydrogenated lecithin and (D) hydrolyzed collagen constituting the liposome is set to 1, it is preferable to contain (E) niacinamide in a blending ratio of 1 or more, and more preferably in the range of 1.25 to 12500. In the case of (E) tranexamic acid, when the total amount of (B) hydrogenated lecithin and (D) hydrolyzed collagen constituting the liposome is set to 1, it is preferable to contain (E) tranexamic acid in a blending ratio of 0.2 or more, and more preferably in the range of 0.25 to 5000. In the case of (E) ε-aminocaproic acid, when the total amount of (B) hydrogenated lecithin and (D) hydrolyzed collagen constituting the liposome is set to 1, it is preferable to contain (E) ε-aminocaproic acid in a blending ratio of 0.02 or more, and more preferably in the range of 0.025 to 5000.

[0031] The collagen liposomes used in this invention have the property that the liposome particles do not break down even when stored for a long period of time. Even when used in cosmetics containing component (E) of this invention, the liposome particles remain intact, resulting in excellent storage stability. For this reason, the cosmetics of this invention can not only be distributed to the market as cosmetics after preparation, but can also be stored for a long period of time, for example, in a manufacturing plant, as a premixed cosmetic ingredient, a "penetrating composition for skin or scalp." Once stored, the "penetrating composition for skin or scalp" can not only be distributed again as 100% of cosmetics, but can also be mixed as an additive into other cosmetics that are not part of this invention. In this case, collagen liposome particles can be mixed into the non-inventive cosmetic in an amount of 0.01 to 99.99% by mass. In this case, the liposome particles are dispersed in the new cosmetic and may be considerably diluted, but they remain stable as particles. Component (E) in the new cosmetic is also considerably diluted. When incorporating a "penetrating composition for skin or scalp" into a new cosmetic product, for example, when making a quasi-drug, if component (E) is niacinamide, the amount of niacinamide should be 3 to 8% by mass relative to the total amount of the new cosmetic product. If it is tranexamic acid, the amount of tranexamic acid should be 0.5 to 5% by mass relative to the total amount of the new cosmetic product. If it is ε-aminocaproic acid, the amount of ε-aminocaproic acid should be 0.005 to 2% by mass relative to the total amount of the new cosmetic product. By adjusting the external phase through post-addition in this manner, a cosmetic product with high skin penetration (skin feel) of each component (E) can be obtained.

[0032] "Method for Producing Liposomes" The liposomes (liposome dispersion) contained in the cosmetic composition of the present invention can be prepared, for example, as follows. First, (B) hydrogenated lecithin and (C) polyhydric alcohol are heated to 60 to 95°C and uniformly dissolved to form a mixture. Separately, (D) hydrolyzed collagen and (A) water are heated to 60 to 95°C and uniformly mixed to form an aqueous solution. A heating temperature of 65 to 90°C is more preferable.

[0033] (B) A mixture of hydrogenated lecithin and (C) polyhydric alcohol is stirred, and an aqueous solution of (D) hydrolyzed collagen dissolved in (A) water is added dropwise. The mixture is then processed using a homomixer or the like to prepare liposomes. The size of the liposomes can be adjusted by pressure filtration using a membrane filter. The size of the liposomes is preferably such that the average particle size measured by dynamic light scattering is 250 nm or less, and more preferably 200 nm or less. If it is desired to impart preservative properties to the liposome dispersion, pentylene glycol (pentanediol) may be added after liposome preparation.

[0034] "Preparation of Cosmetics" The cosmetic composition of the present invention is a cosmetic composition obtained by mixing liposomes (which may be liposome dispersions or liposome particles obtained by removing the dispersion medium from the liposome dispersion) containing essential components (A + B + C + D) with one or more selected from (E) niacinamide, tranexamic acid, and ε-aminocaproic acid. The cosmetic composition of the present invention is obtained by further adding one or more of (E) niacinamide, tranexamic acid, and ε-aminocaproic acid to pre-prepared liposomes. Alternatively, a cosmetic composition (such as a lotion, emulsion, cream, gel, or hair growth agent) containing one or more of (E) niacinamide, tranexamic acid, and ε-aminocaproic acid may be prepared, and then liposomes (which may be liposome dispersions or liposome particles obtained by removing the dispersion medium from the liposome dispersion) containing separately prepared essential components (A + B + C + D) may be added to obtain the cosmetic composition of the present invention. In other words, the cosmetic composition of the present invention is a cosmetic composition to which one or more selected from (E) niacinamide, tranexamic acid, and ε-aminocaproic acid are added to liposomes containing (A) water, (B) hydrogenated lecithin, (C) polyhydric alcohol, and (D) hydrolyzed collagen, or a cosmetic composition to which one or more selected from (E) niacinamide, tranexamic acid, and ε-aminocaproic acid are added to liposomes containing (A) water, (B) hydrogenated lecithin, (C) polyhydric alcohol, and (D) hydrolyzed collagen. It should be noted that the cosmetic composition of the present invention does not require the presence of component (E) in the internal phase of the liposomes, but this does not exclude the presence of component (E) in the internal phase of the liposomes. A cosmetic composition in which component (E) is present in the internal phase of the liposomes can be made by including component (E) during the preparation of the liposomes.

[0035] In the cosmetic composition of the present invention, component (E) is water-soluble and has difficulty passing through the lipid bilayer. Furthermore, it exhibits permeability equivalent to that of component (E) when encapsulated in liposomes. Therefore, it is presumed that most of component (E) is attached to the outer membrane of liposomes (collagen liposomes) by hydrogen bonding. Although we investigated whether it is possible to confirm that component (E) is attached to the outer membrane of liposomes, there is currently no method to analyze liposomes with a size of 100-300 nm, making this impossible or impractical.

[0036] Preferred cosmetic compositions of the present invention include lotions, serums, essences, toners, cosmetic liquids, creams, hair tonics, and hair essences. In formulations that form a strong film after application to the skin or scalp, such as peeling packs and hair styling products, the penetration of component (E) may not be easily perceived. The cosmetic compositions of the present invention may contain any components as long as they do not hinder the effects of the present invention. Examples include vitamins, beauty ingredients, whitening agents, emollients, moisturizers, chelating agents, antioxidants, UV absorbers, pH adjusters, colorants, and fragrances (including essential oils).

[0037] The present invention will be described in detail below based on examples, but the present invention is not limited thereto. The units of composition in the table are in mass percent. In the table, "-" indicates that liposomes were not formed. "Pre-added" indicates that component (E) was added during liposome preparation. "Post-added" indicates that component (E) was added after liposomes were formed.

[0038] The ingredients used in the table are as follows: (A) Water, purified water (B) Hydrogenated lecithin, "SLP-PC92H", phosphatidylcholine 90% or more, manufactured by Tsuji Oil Co., Ltd. (C) Polyhydric alcohol, butylene glycol (BG), "1,3-butylene glycol (UK)", manufactured by Daicel Corporation; Pentylene glycol, "Diol PD", manufactured by Higher Alcohol Industry Co., Ltd. (D) Hydrolyzed collagen, "CTP-F60", manufactured by Zerice Co., Ltd. (E) Active ingredient, niacinamide, "nicotinamide", manufactured by DSM Corporation; tranexamic acid, "tranexamic acid", manufactured by Kyowa Pharma Chemical Co., Ltd.; ε-aminocaproic acid, "ε-aminocaproic acid", manufactured by Kyowa Pharma Chemical Co., Ltd.

[0039] Cosmetics for Examples 1-3, Comparative Examples 1-5, and Reference Example 1 were prepared with the compositions shown in Tables 1 and 2. (Preparation Method) (B) Hydrogenated lecithin and (C) Polyhydric alcohol (butylene glycol) were weighed out and uniformly dissolved at 70°C. An aqueous solution in which (D) hydrolyzed collagen and (A) water were uniformly dissolved was added to this solution and processed using a homomixer (Primix Homomixer MARK II, 6500 rpm) to prepare liposomes. Next, in order to impart a preservative effect, (C) Polyhydric alcohol (pentylene glycol) was added, and the mixture was further filtered under pressure using a membrane filter with a pore size of 0.2 μm to adjust the particle size [liposome dispersion]. (E) Niacinamide, tranexamic acid, and ε-aminocaproic acid were added to the liposome dispersion and mixed to obtain the cosmetic composition of the present invention (Examples 1-3. This preparation method is called post-addition of active ingredients). Reference Example 1 involves adding tranexamic acid from the time of liposome preparation (this preparation method is called pre-addition of the active ingredient). In this method, a cosmetic product is obtained in which tranexamic acid is encapsulated in liposomes.

[0040] "Measurement of Permeability" Using an in vivo confocal Raman spectrometer (gen2-SCA, manufactured by RiverD International B.V.), the skin permeability of tranexamic acid, niacinamide, and ε-aminocaproic acid was evaluated. 1 mL of the cosmetic prepared on a 5 mm square cotton was impregnated and affixed to the inner part of the forearm. The affixed cotton was occluded with surgical tape, and after 30 minutes, the surgical tape and cotton were peeled off. The liquid remaining at the affixed site was removed with a paper wiper such as Kimwipe, and the permeability of each component was measured. "Evaluation of Permeability" By analyzing the results measured by the in vivo confocal Raman spectrometer, for example, as shown in Figure 1, the Raman light intensity of the components at various depths of the skin can be obtained. Here, the Raman light intensity at a skin depth of 12 μm was compared, and those with a significantly increased intensity were judged to have improved permeability.

[0041] The compositions of the cosmetics of Examples 1 to 3, Comparative Examples 1 to 5, and Reference Example 1 and the timing of addition of component (E) are shown in Tables 1 and 2. In the tables, "-" indicates a composition that does not contain liposomes, meaning that all components were mixed and dissolved at once.

[0042]

[0043] The evaluation results of the permeability of Examples 1 to 3, Comparative Examples 1 to 5, and Reference Example 1 are shown in Figures 1 to 3, respectively. In each figure, the horizontal axis is the skin depth, and the vertical axis is the Raman light intensity derived from each active component (E). The difference in the memory width of the axis in the figure is not a particular problem because the Raman light intensity obtained varies depending on the component.

[0044] [Results] From the results of Reference Example 1 and Example 1 in Figure 1, it was found that by adopting the configuration of the present invention (collagen liposomes + post-addition of tranexamic acid), the same level of permeability as when the active ingredient (tranexamic acid) is encapsulated in liposomes can be obtained even without encapsulating the active ingredient (tranexamic acid) in liposomes. The cosmetic composition of Comparative Example 1, in which tranexamic acid was encapsulated in liposomes without hydrolyzed collagen, had lower permeability than the cosmetic composition of Example 1, in which collagen liposomes and the active ingredient (tranexamic acid) coexisted. From this, it was found that the cosmetic composition of the present invention has higher permeability than conventional liposome formulations and is a superior permeable cosmetic composition. Comparative Examples 2 and 3 are cosmetic compositions without liposomes, and Comparative Example 3 has a composition containing hydrolyzed collagen, but in all cases, the permeability of the active ingredient (tranexamic acid) was low. Figure 2 compares Example 2 with Comparative Example 4, which does not contain liposomes. It was found that by adopting the configuration of the present invention (collagen liposomes + post-addition of niacinamide), a cosmetic with high permeability of the active ingredient (niacinamide) can be obtained. Figure 3 compares Example 3 with Comparative Example 5, which does not contain liposomes. It was found that by adopting the configuration of the present invention (collagen liposomes + post-addition of ε-aminocaproic acid), a cosmetic with high permeability of the active ingredient (ε-aminocaproic acid) can be obtained.

[0045] Comparative Examples 6, 7, 8, 9 In the composition of Example 1, tranexamic acid was replaced with other water-soluble active ingredients (ascorbyl glucoside, pyridoxine hydrochloride, allantoin, trehalose) and tested similarly. Cosmetics (Comparative Examples 6, 7, 8, 9) mixed with liposomes containing (A) water, (B) hydrogenated lecithin, (C) polyhydric alcohol, and (D) hydrolyzed collagen, and other water-soluble active ingredients (ascorbyl glucoside, pyridoxine hydrochloride, allantoin, trehalose) did not show an increase in permeability. From this, it was found that the effect of increasing the permeability of component (E) in cosmetics mixed with liposomes containing (A) water, (B) hydrogenated lecithin, (C) polyhydric alcohol, and (D) hydrolyzed collagen, and component (E) "niacinamide, tranexamic acid, and ε-aminocaproic acid," is a specific effect or phenomenon that is expressed only with the specific component (E).

Claims

1. A cosmetic composition characterized by comprising (A) water, (B) hydrogenated lecithin, (C) polyhydric alcohol, (D) liposomes containing hydrolyzed collagen, and (E) one or more selected from niacinamide, tranexamic acid, and ε-aminocaproic acid.

2. (C) The cosmetic composition according to claim 1, characterized in that the polyhydric alcohol comprises one or more selected from butylene glycol, pentylene glycol, dipropylene glycol, octanediol, hexanediol, glycerin, and diglycerin.

3. The cosmetic composition according to claim 1 or 2, characterized in that the mass ratio of component (B) to component (D) is 5:1 to 1:

1.

4. The cosmetic composition according to claim 1 or 2, characterized in that the content of a skin penetration inhibitor is 1% by mass or less relative to the total amount of the cosmetic composition.

5. The cosmetic composition according to claim 1 or 2, characterized in that the phosphatidylcholine content of component (B) is 86% by mass or more.

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