Sheet-like cosmetic

Abstract

To provide a technique capable of suppressing an increase in the quantitative value of a glycyrrhizinate in a sheet-like cosmetic obtained by impregnating a sheet base material with a cosmetic blended with the glycyrrhizinate.SOLUTION: The present invention provides a sheet-like cosmetic in which a sheet base material is impregnated with a composition containing a glycyrrhizinate (A) and a buffering agent (B), wherein the pH of the composition maintained by the buffering agent (B) is 5.0 to 7.5, whereby an increase in the quantitative value of the glycyrrhizinate in the sheet-like cosmetic can be suppressed.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a sheet-like cosmetic impregnated with a cosmetic containing a glycyrrhizinate salt. [Background technology]

[0002] Glycyrrhizic acid and its salts are incorporated as anti-inflammatory agents into various cosmetics such as shampoos, conditioners, facial cleansers, medicated soaps, lotions, emulsions, packs, medicated creams, and hair growth agents. As a cosmetic containing glycyrrhizinate, for example, Patent Document 1 discloses a cosmetic containing (A) a polyhydric alcohol, (B) a glycyrrhizinate, (C) a mukurossi peel extract, (D) an oil, and (E) water.

[0003] Among salts of glycyrrhizinic acid, monoammonium salt and dipotassium salt are listed in the Japanese Standards for Cosmetic Ingredients (Non-Patent Document 1). In particular, dipotassium glycyrrhizinate (hereinafter also referred to as "GK2") is known to have anti-inflammatory and anti-allergic effects.

[0004] Incidentally, it has been reported that when glycyrrhizinates are blended into such cosmetics, the quantitative value is slightly elevated when quantified by HPLC (Non-Patent Document 1). Non-Patent Document 1 focuses on the fact that the quantitative value of glycyrrhizinates is slightly elevated by alkali in cleansing agents with a pH of 9 to 10, such as cleansing products. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2022-164249 [Non-patent literature]

[0006] [Non-Patent Document 1] Masato Hayashi et al., "Elucidation of Abnormal Behavior in the Determination of Glycyrrhizinate in Quasi-drugs by High-Performance Liquid Chromatography," Pharmaceutical Journal, 1992, Vol. 112(7), pp. 496-502 Summary of the Invention [Problem to be solved by the invention]

[0007] The present inventors have confirmed that when glycyrrhizinate, particularly GK2, is blended into skincare products such as sheet masks, lotions, and milks, the quantitative value of GK2 gradually increases over time. In particular, in sheet cosmetics such as sheet masks, in which a sheet substrate such as a nonwoven fabric is impregnated with a beauty serum or the like and applied to the face, the quantitative value of GK2 in the squeezed liquid increases immediately after the nonwoven fabric is impregnated with the GK2-containing cosmetic product, unlike other lotions and milk preparations.

[0008] The increase in the quantitative value of GK2 in sheet-type cosmetics as described above appears to differ from the increase in the quantitative value reported in Non-Patent Document 1, and the cause is unknown. If the increase in the quantitative value approaches the upper limit of the content standard, there is a risk that the content standard will be exceeded. Therefore, there is a need to investigate the cause of the increase in the quantitative value of GK2 in sheet-type cosmetics and to propose a method for suppressing the increase in the quantitative value of GK2.

[0009] Therefore, an object of the present invention is to provide a technology that can suppress an increase in the quantitative value of glycyrrhizinate in a sheet-type cosmetic in which a sheet substrate is impregnated with a cosmetic containing glycyrrhizinate. [Means for solving the problem]

[0010] To solve the above problem, the inventors impregnated 12 types of nonwoven fabrics and gauze made of different materials with a GK2 aqueous solution and measured the changes in the quantitative value of GK2. Focusing on the pH of the nonwoven fabrics, the inventors found that an increase in the quantitative value of GK2 was observed in nine types of nonwoven fabrics with a nearly neutral pH. On the other hand, no increase in the quantitative value of GK2 was observed in nonwoven fabrics with a pH nearly equal to that of the GK2 aqueous solution. Therefore, they concluded that maintaining the pH when impregnating nonwoven fabrics with a GK2 aqueous solution is important for suppressing the increase in the quantitative value of GK2.

[0011] Therefore, buffer solutions of pH 3, 4, 5, 6, 7, 8, and 9 were prepared, and these were blended with an aqueous GK2 solution and impregnated into a nonwoven fabric. As a result, it was found that the addition of buffer solutions of pH 5, 6, and 7 suppressed the increase in the quantitative value of GK2. It was also shown that the addition of buffer solutions of pH 5, 6, and 7 hardly changed the quantitative value of GK2 even under accelerated conditions. It was also found that the addition of a buffer in a relatively larger amount than that typically blended in cosmetics effectively suppressed the increase in the quantitative value of glycyrrhizinate. The present invention was made based on these findings.

[0012] The present invention provides a sheet-type cosmetic in which a sheet substrate is impregnated with a composition containing a glycyrrhizinate (A) and a buffer (B), wherein the pH of the composition maintained by the buffer (B) is 5.0 to 7.5.

[0013] The present invention also provides the above-mentioned sheet-form cosmetic, wherein the total content of the buffer (B) is 0.6% by mass or more.

[0014] The present invention also provides the sheet-form cosmetic, wherein the buffer (B) is at least one selected from the group consisting of a combination of citric acid and a salt thereof, a combination of succinic acid and a salt thereof, and a combination of monohydrogen phosphate and dihydrogen phosphate.

[0015] The present invention also provides the above-mentioned sheet-form cosmetic, wherein the glycyrrhizinate is dipotassium glycyrrhizinate.

[0016] The present invention also provides the above-mentioned sheet-type cosmetic, wherein the sheet substrate is a nonwoven fabric.

[0017] The present invention also provides a method for producing a sheet-type cosmetic, comprising the steps of preparing a composition containing a glycyrrhizinate salt (A) and a buffer (B), the pH of which is maintained by the buffer (B) at 5.0 to 7.5, and impregnating a sheet substrate with the composition.

[0018] The present invention also provides a method for suppressing an increase in the quantitative value of glycyrrhizinate in a sheet-type cosmetic, the method comprising the steps of preparing a composition containing glycyrrhizinate (A) and a buffer (B), the pH of which is maintained by the buffer (B) at 5.0 to 7.5, and impregnating a sheet substrate with the composition. [Effects of the Invention]

[0019] By using the present invention, it is possible to suppress an increase in the quantitative value of glycyrrhizinate in a sheet-type cosmetic in which a sheet substrate is impregnated with a cosmetic containing glycyrrhizinate such as GK2. [Brief explanation of the drawings]

[0020] [Figure 1] 1 is a graph showing changes in pH when a nonwoven fabric is impregnated with each of the GK2-containing buffer solutions prepared using the stock solutions of buffer solutions of pH 5, 6, and 7, and 2- to 20-fold dilutions. [Figure 2] Graph showing the change in GK2 content when nonwoven fabric is impregnated with GK2-containing buffer solutions of pH 5, 6, and 7. DETAILED DESCRIPTION OF THE INVENTION

[0021] The sheet-type cosmetic of the present invention is obtained by impregnating a sheet substrate with a composition containing glycyrrhizinate (A) and a buffer (B) (hereinafter also referred to as "GK2 buffer solution"). The pH of the composition, maintained by the buffer (B), is 5.0 to 7.5.

[0022] Each component and sheet substrate will be described in detail below.

[0023] [Glycyrrhizinate (A)] Glycyrrhizic acid is a triterpene glycoside known for its anti-inflammatory and anti-allergic effects. Glycyrrhizic acid is one of the components extracted from licorice, a perennial plant in the legume family.

[0024] Glycyrrhizinate is a salt of glycyrrhizinic acid and any base, and includes, for example, glycyrrhizinic acid, dipotassium glycyrrhizinate, sodium glycyrrhizinate, and ammonium glycyrrhizinate. In this specification, glycyrrhizinic acid is also included in the salts. In the present invention, the glycyrrhizinate is preferably dipotassium glycyrrhizinate (GK2). Glycyrrhizinate may be provided not only as a 100% pure material, but also as a mixture containing other ingredients such as its analogues.

[0025] In the present invention, the content of glycyrrhizinate in the composition of the present invention is not particularly limited, but is, for example, 0.01 to 2 mass%, preferably 0.05 to 1 mass%, and more preferably 0.05 to 0.5 mass%. Furthermore, when glycyrrhizinate is provided as a mixture containing other ingredients such as its analogs, the content of glycyrrhizinate in the composition of the present invention refers to the content of glycyrrhizinate with 100% purity excluding other ingredients.

[0026] Buffer (B) A buffer is a substance that, when added to a solution, maintains the pH of the solution at a specific value. The addition of a buffer can suppress a decrease or increase in pH when a small amount of acid or base is added. A solution to which a buffer is added and in which pH fluctuations caused by a small amount of acid or base are suppressed is called a buffer solution. In other words, the composition of the present invention can be called a buffer solution.

[0027] The buffer used in the present invention is not particularly limited as long as it is a buffer usable in cosmetics, and can maintain the pH of the solution at 5.0 to 7.5 when added to a solution. The buffer is not particularly limited, but can be composed of a combination of a weak acid and its conjugate base, or a weak base and its conjugate acid. Examples of buffers that can be used include combinations of citric acid and its salt, succinic acid and its salt, monohydrogen phosphate and dihydrogen phosphate, monohydrogen phosphate and phosphoric acid, acetic acid and acetate, lactic acid and its salt, and ammonia and its salt. The buffer used in the present invention is not limited to these combinations, and may also be a combination that can be combined to form a buffer solution, such as citric acid and succinate, succinic acid and citrate, or phosphate and citrate. Salts used in buffers include, for example, sodium salts, potassium salts, magnesium salts, ammonium salts, and calcium salts. A single combination of buffers may be used alone, or two or more combinations may be used in combination.

[0028] In the present invention, the buffer is not particularly limited, and may be, for example, a combination of buffers for preparing a citrate buffer, a succinate buffer, a phosphate buffer, etc. The buffer is preferably a combination of citric acid and its salt, a combination of succinic acid and its salt, or a combination of monohydrogen phosphate and dihydrogen phosphate, and more preferably a combination of citric acid and its sodium salt, a combination of succinic acid and its sodium salt, or a combination of sodium monohydrogen phosphate and sodium dihydrogen phosphate.

[0029] The pH of the composition used in the present invention is maintained at a specific value by a buffer. This specific value may be within the range of 5.0 to 7.5, more preferably within the range of 5.0 to 7.2, and even more preferably within the range of 5.0 to 7.0. The buffer may be, for example, a mixture of a weak acid and its conjugate base in a ratio that results in the desired pH, or the pH may be adjusted to the desired value using a protonic acid or the like. The protonic acid used to adjust the pH is not particularly limited, but may include, for example, hydrochloric acid, phosphoric acid, citric acid, sulfuric acid, and nitric acid. The buffer can be adjusted to the desired pH by, for example, combining a weak acid and its conjugate base in appropriate concentrations.

[0030] In the present invention, the total content of buffering agents in the composition is not particularly limited, but for example, if it is 0.6% by mass or more, it can sufficiently suppress an increase in the quantitative value of glycyrrhizinate. The total content of buffering agents is preferably 1.0% by mass or more, more preferably 1.3% by mass or more. These concentrations are higher than the amounts of buffering agents typically incorporated into cosmetics, but in the present invention, by incorporating a larger amount of buffering agent than usual, it is possible to sufficiently suppress an increase in the quantitative value of glycyrrhizinate. The upper limit of the total content of buffering agents is not particularly limited, but from the viewpoint of preventing the risk of precipitation and suppressing adverse effects on the feel, it may be, for example, 5.0% by mass or less, preferably 4.0% by mass or less, more preferably 3.0% by mass or less.

[0031] In the present invention, by incorporating a buffer, it is possible to suppress pH fluctuations after the GK2-blended composition is impregnated into the sheet substrate, and to suppress an increase in the quantitative value of GK2.

[0032] [Other ingredients] The composition used in the present invention may further contain components other than the above-mentioned components (A) and (B) to the extent that the object of the present invention is not impaired. These other components include, for example, various cosmetic ingredients such as oils and fats, surfactants, moisturizers, whitening agents, pH adjusters, binders, thickeners, polyhydric alcohols, essential oils, fragrances, preservatives, antioxidants, UV absorbers, pigments, crushed plant products, herbal medicines, inorganic salts, inorganic acids, detergents, and emulsifiers. Furthermore, various physiologically active substances may be used as other components, such as anti-inflammatory agents, anti-aging agents, UV protection agents, astringents, antioxidants, blood circulation promoters, antibacterial agents, disinfectants, cooling agents, warming agents, wound healing promoters, irritation soothing agents, analgesics, and cell activators.

[0033] The oils and fats may be ingredients commonly used in cosmetics, such as vegetable oils and fats such as soybean oil, almond oil, paraffin, cetanol, avocado oil, olive oil, jojoba oil, coconut oil, palm oil, rice bran oil, egg yolk oil, castor oil, squalane, lanolin, liquid paraffin, and white petrolatum; animal oils and fats such as beef tallow, lard, horse fat, turtle oil, mink oil, Purcellin oil, and squalane; and synthetic oils and fats such as methylpolysiloxane, behenyl alcohol, glyceryl tricaprate, glyceryl trioctanoate, liquid paraffin, DHA, and EPA.

[0034] Examples of surfactants that can be used include anionic surfactants such as sodium lauryl sulfate, triethanolamine lauryl sulfate, and lauric acid diethanolamide; cationic surfactants such as stearyl trimethylammonium chloride, cetyl trimethylammonium chloride, and benzalkonium chloride; nonionic surfactants such as glyceryl monostearate, sorbitan monostearate, polyoxyethylene (20) sorbitan monostearate, polyoxyethylene hydrogenated castor oil, sucrose esters, and fatty acid amides; polymeric surfactants, fluorine-based surfactants, silicone-based surfactants, polypeptide derivatives, and natural surfactants.

[0035] Examples of moisturizing agents that can be used include synthetic moisturizing agents such as sodium pyrrolidone carboxylate and pantetheine-S sulfonate; and natural moisturizing agents such as hyaluronic acid, elastin, keratin, dermatan sulfate, collagen, placenta extract, royal jelly and their hydrolysates, microbial fermentation liquids such as chitin, chitosan, pectin, glucosamine and N-acetylglucosamine, other plant and animal extracts, vegetable oils and their esters, and derivatives.

[0036] Examples of whitening agents that can be used include ascorbic acid and its salts or derivatives, arbutin and its derivatives, placenta extracts, and other plant- or animal-derived extracts.

[0037] The pH adjuster may contain a pH adjuster other than component (B), and examples of the pH adjuster that can be used include organic acids such as citric acid, lactic acid, salicylic acid, tartaric acid, malic acid, benzoic acid, sodium citrate, fumaric acid, sodium monohydrogen phosphate, and potassium dihydrogen phosphate, inorganic acids, and salts thereof.

[0038] As the binder and thickener, those generally used in cosmetics, such as sodium carboxymethylcellulose, methylcellulose, casein, pectin, starch, sodium alginate, polyvinyl alcohol, polyvinylpyrrolidone, locust bean gum, agar, carbopol, xanthan gum, and bentonite, can be used.

[0039] Examples of polyhydric alcohols that can be used include glycerin, propylene glycol, sorbitol, polyethylene glycol, 1,3-butylene glycol, dipropylene glycol, and polyoxyethylene glycerin (26E.O).

[0040] Examples of essential oils and fragrances that can be used include natural and synthetic fragrances such as lavender oil, jasmine oil, rose oil, lemon oil, orange oil, peppermint oil, thyme oil, calamus oil, fennel oil, cedar oil, hiba oil, raspberry oil, cypress oil, rose oil, eucalyptus oil, camphor, peppermint oil, spearmint oil, geraniol, mandarin oil, spruce oil, citronellol, terpenes, coffee oil, tea oil, camellia oil, and raspberry ketone.

[0041] Examples of preservatives that can be used include paraoxybenzoic acid esters such as methylparaben, ethylparaben, propylparaben, and butylparaben, phenoxyethanol, ethanol, and dehydroacetic acid.

[0042] Examples of antioxidants that can be used include EDTA4Na, EDTA2Na, butyloxytoluene, hydroxybutyltoluene, butylhydroxyanisole (BHA), dibutylhydroxytoluene (BHT), and derivatives thereof.

[0043] The ultraviolet absorber is not particularly limited as long as it has the property of selectively absorbing ultraviolet light, and examples that can be used include oxybenzone, oxybenzonesulfonic acid, tetrahydroxybenzophenone, dihydroxymethoxybenzophenone sodium sulfonate, dihydroxymethoxybenzophenone, dihydroxybenzophenone, cinoxate, methyl diisopropylcinnamate, octyl methoxycinnamate, glyceryl para-aminobenzoate, and octyl para-aminobenzoate.

[0044] Examples of pigments that can be used include red iron oxide, yellow iron oxide, black iron oxide, titanium oxide, nylon powder, zinc oxide, sericite, mica, talc, carbon, and medicinal charcoal.

[0045] Examples of crushed plants and herbal medicines that can be used include crushed, dried, and extracts of lemon peel, seaweed, cypress, Japanese cypress, fucus, rice bran, calamus, ginger, licorice, tangerine peel, yuzu, angelica tree, carrot, mint, cinnamon bark, Ubai, mugwort, Houttuynia cordata, peach blossom, chamomile, aloe, jasmine, rose hip, lavender, guava, Scutellaria root, wolfberry, lychee, elderberry, Angelica tree, Aralia aralia, burdock, black sesame, black rice, Fujisanchi ginseng, Korean ginseng, Panax notoginseng, Sekkotsu grass, and Cnidium rhizome.

[0046] Examples of inorganic salts and inorganic acids that can be used include sodium chloride, sodium hydrogencarbonate, sodium carbonate, boric acid, borax, sodium sulfate, sodium sulfide, potassium sulfide, sodium nitrate, calcium nitrate, ammonium sulfate, sodium thiosulfate, calcium hydrogenphosphate, potassium chloride, ammonium chloride, sodium phosphate, sodium hyposulfite, calcium thiosulfate, sulfur, sodium sesquicarbonate, magnesium sulfate, magnesium chloride, silicic anhydride, metasilicic acid, boric acid, magnesium carbonate, magnesium hydroxide, magnesium dihydride, and dried seawater.

[0047] The detergent may be, for example, a fatty acid soap, an anionic surfactant such as sodium lauryl sulfate or alkyl ether carboxylate, or an aliphatic detergent.

[0048] The emulsifier may be a substance known as a cosmetic raw material, and examples thereof include sucrose fatty acid esters such as sucrose laurate, sucrose myristate, sucrose palmitate, sucrose stearate, sucrose oleate, and sucrose erucate; tetraglycerin monostearate, tetraglycerin monooleate, tetraglycerin tristearate, hexaglycerin monolaurate, hexaglycerin monomyristate, hexaglycerin monostearate, hexaglycerin tristearate, decaglycerin monolaurate, decaglycerin monomyristate, decaglycerin monostearate, decaglycerin distearate, decaglycerin tristearate, decaglycerin pentastearate, decaglycerin monolaurate, decaglycerin monomyristate, decaglycerin monostearate, decaglycerin distearate, decaglycerin tristearate, decaglycerin pentastearate, decaglycerin monos ... Polyglycerol fatty acid esters such as sorbitan monoisostearate, decaglycerol diisostearate, decaglycerol pentaisostearate, decaglycerol monooleate, decaglycerol trioleate, and decaglycerol pentaoleate; sorbitan branched fatty acid esters such as sorbitan monoisostearate, sorbitan sesquiisostearate, and sorbitan triisostearate; lecithins such as soybean lecithin, egg yolk lecithin, hydrogenated soybean lecithin, hydrogenated egg yolk lecithin, lysolecithin and / or hydrogenated lysolecithin obtained by enzymatically treating these lecithins to form monoacylated forms, and hydroxylated hydroxylecithin; and glycerol branched fatty acid esters such as glyceryl monoisostearate, glyceryl sesquiisostearate, and glyceryl diisostearate.

[0049] In addition to the above-mentioned components, the composition used in the present invention may optionally contain milk-derived ingredients such as lactose, milk, and condensed milk; inorganic pigments such as titanium and talc; disinfectants such as isopropylmethylphenol, chlorhexidine hydrochloride, and chlorhexidine gluconate; vitamins and coenzymes such as vitamin A, vitamin B1, vitamin B2, vitamin B6, vitamin P, CoQ10, CoQ9, CoQ8, and thioctic acid; fluidizing agents such as silicic anhydride and synthetic aluminum silicate; and tar-based pigments for pharmaceuticals, quasi-drugs, and cosmetics.

[0050] In addition to the above-mentioned components, the composition used in the present invention may also contain various cosmetic ingredients such as medicinal ingredients for the purposes of beauty, facial beauty and skin treatment.

[0051] Medicinal ingredients include, for example, avocado extract, hydrangea extract, althea extract, arnica extract, apricot extract, apricot kernel extract, ginkgo extract, fennel extract, turmeric extract, oolong tea extract, echinacea leaf extract, phellodendron bark extract, barley extract, Dutch mustard extract, orange extract, hydrolyzed wheat powder, hydrolyzed silk, chamomilla extract, carrot extract, artemisia capillaris extract, kalkade extract, kiwi extract, cinchona extract, cucumber extract, guanosine, kumazasa extract, walnut extract, grapefruit extract, clematis extract, yeast extract, comfrey extract, cowberry extract, bupleurum extract, umbilical cord extract, salvia extract, soapwort extract, bamboo grass extract, hawthorn extract, shiitake mushroom extract, rehmannia root extract, lithospermum root extract, linden extract, meadowsweet extract, calamus root extract, white birch extract, horsetail extract, honeysuckle Examples of useful extracts that can be used include Japanese whiting, common weed extract, hawthorn extract, elderberry extract, yarrow extract, peppermint extract, mallow extract, Swertia japonica extract, Chinese laurel extract, thyme extract, clove extract, Imperata cylindrica extract, tomato extract, natto extract, wild rose extract, hibiscus extract, Bakumondo extract, parsley extract, Parietaria extract, Japanese knotweed extract, bisabolol, coltsfoot extract, butterbur honey, Japanese gourd extract, Poria columbine extract, butcher's broom extract, grape extract, propolis, loofah extract, peppermint extract, linden extract, hop extract, pine extract, horse chestnut extract, Asian skunk cabbage extract, Soapberry extract, peach leaf extract, cornflower extract, eucalyptus extract, apple extract, lettuce extract, astragalus extract, rose extract, rosemary extract, and Roman chamomile extract.

[0052] The composition used in the present invention may also contain anti-inflammatory agents such as ε-aminocaproic acid, β-glycyrrhetinic acid, lysozyme chloride, guaiazulene, and hydrocortisone, blood circulation promoters such as vitamin C, vitamin D, calcium pantothenate, biotin, nicotinamide, vitamin E, and vitamin E derivatives, vitamins such as β-carotene and carotenoid derivatives, active ingredients such as allantoin, diisopropylamine dichloroacetate, and 4-aminomethylcyclohexanecarboxylic acid, antioxidants such as flavonoids, tannins, lignans, and saponins, wound healing agents such as γ-oryzanol and protease, cepharanthine, capsicum tincture, hinokitiol, iodized garlic extract, Pyridoxine hydrochloride, nicotinic acid, nicotinic acid derivatives, acetyl pantothenyl ethyl ether, estradiol, ethynyl estradiol, capronium chloride, diphenhydramine hydrochloride, camphor, nonylic acid vanillylamide, nonanoic acid vanillylamide, piroctone olamine, glyceryl pentadecanoate, l-menthol, menthol pyrrolidone carboxylate, mononitroguaiacol, urea, resorcinol, γ-aminobutyric acid, benzethonium chloride, mexiletine hydrochloride, auxin, female hormones and female hormone-like substances, cantharides tincture, cyclosporine, analgesics, tranquilizers, antihypertensives, antibiotics, antihistamines, and antibacterial substances can also be optionally blended.

[0053] The above-exemplified components may be used singly or in combination of two or more.

[0054] [Sheet-type cosmetics] The sheet-form cosmetic of the present invention is obtained by impregnating a sheet substrate with the above-mentioned composition. The sheet-form cosmetic of the present invention may be used by being attached to the skin of a user, such as the face, body surface, or scalp, and may be, for example, a sheet mask, a face mask, an eye sheet, a gel sheet, an antiperspirant sheet, a sunscreen sheet, a makeup remover sheet, or a hairstyling sheet.

[0055] The composition used in the present invention may be, for example, a skin lotion, emulsion, serum, cream, ointment, gel, lotion, oil, wipe-off cosmetic, body soap, hand soap, soap, shampoo, rinse, treatment, hair styling product, etc., depending on the purpose of the sheet-type cosmetic.

[0056] [Sheet substrate] The sheet substrate used in the present invention may be any of various sheet-like materials that can be impregnated with a chemical solution, such as nonwoven fabric or woven fabric, etc. In the present invention, the sheet substrate is preferably nonwoven fabric.

[0057] The material of the sheet substrate is not particularly limited, and may be natural fiber, chemical fiber, regenerated fiber, etc. Examples of the material for the sheet substrate include cotton, hemp, pulp, silk, carbon, cellulose, polyamide, nylon, polyester, acrylic, polyacrylonitrile, vinylon, polyolefin, polyurethane, polyethylene, polypropylene, polyethylene terephthalate, rayon, cupra, and lyocell.

[0058] The sheet substrate is not particularly limited, but may be a sheet made of, for example, cotton, pulp, carbon, polyester, polyethylene, polypropylene, polyethylene terephthalate, rayon, cupra, or any combination thereof. The sheet substrate may also be a sheet in which at least one of pulp, cotton, rayon, or the like is reinforced with a thermoplastic resin such as polyethylene, polypropylene, or polyethylene terephthalate.

[0059] The sheet substrate may be a laminate (laminated sheet), such as a laminate of woven fabric, a laminate of nonwoven fabric, or a laminate of woven fabric and nonwoven fabric.

[0060] The nonwoven fabric is not particularly limited, but examples thereof include spunbond nonwoven fabric, spunlace nonwoven fabric, thermal bond nonwoven fabric, needle punch nonwoven fabric, and stitch bond nonwoven fabric.

[0061] The pH of the sheet substrate is not particularly limited and can be any pH. In the present invention, even if the pH of the sheet substrate is, for example, 5.0 or higher, an increase in the quantitative value of glycyrrhizinate can be suppressed.

[0062] The sheet substrate can be produced by a known production method depending on the type of woven fabric, nonwoven fabric, etc. Commercially available products can also be used as the sheet substrate.

[0063] The shape of the sheet substrate can be any shape depending on the area to which the sheet cosmetic is applied, the purpose, etc. For example, in the case of a sheet mask to be applied to the face, the shape can be made to fit the face. In addition, the shape of the sheet substrate is not particularly limited and can be various shapes such as a circle, an oval, a square, and a rectangle.

[0064] The sheet-form cosmetic of the present invention may be a sheet substrate impregnated with the above-described composition, which is placed in a container and sealed. The container is not particularly limited, and may be, for example, a pillow bag, a gusset bag, a pouch, a bottle, a box, a jar, or a tray container.

[0065] The material of the container is not particularly limited, but may be, for example, a metal such as aluminum, a resin such as polyethylene terephthalate, polyethylene, or polypropylene, paper, or glass.

[0066] The means for storing and sealing the sheet-form cosmetic of the present invention in a container is not particularly limited, but for example, a means can be used in which the sheet substrate and the composition are placed in the container in any order, and the container is sealed in a state in which the sheet substrate is immersed in the composition.

[0067] One container may contain one sheet substrate or two or more sheets.

[0068] The amount of the composition impregnated per gram of sheet substrate is not particularly limited, but is, for example, 5 ml to 15 ml.

[0069] [Method of manufacturing sheet-type cosmetic material] The present invention also provides a method for producing a sheet-type cosmetic, which comprises the steps of preparing a composition containing a glycyrrhizinate salt (A) and a buffer (B) and having a pH maintained by the buffer (B) of 5.0 to 7.5, and impregnating a sheet substrate with the composition.

[0070] [Method for suppressing increases in quantitative values ​​of glycyrrhizinate] The present invention also provides a method for suppressing an increase in the quantitative value of glycyrrhizinate, which comprises the steps of preparing a composition containing glycyrrhizinate (A) and a buffer (B), the pH of which is maintained by the buffer (B) at 5.0 to 7.5, and impregnating a sheet substrate with the composition.

[0071] In this specification, the quantitative value of glycyrrhizinate refers to the content of glycyrrhizinate in a composition measured by any quantitative method. The composition to be measured for the quantitative value of glycyrrhizinate can be a composition collected from a sheet substrate after the sheet substrate is impregnated with the composition, for example, a liquid squeezed from the sheet substrate.

[0072] The method for quantifying glycyrrhizinate is not particularly limited, and various analytical methods such as liquid chromatography (LC) or gas chromatography (GC) can be used. Liquid chromatography includes, for example, high performance liquid chromatography (HPLC).

[0073] Additionally, analytical methods that can be used include the external standard method (absolute calibration curve method) and the internal standard method. The external standard method involves analyzing a standard sample prepared with a target compound at a known concentration, creating a calibration curve in advance based on the area or height of the peak corresponding to the target compound, and calculating the measured value from the value of the area or height of the peak in the analysis result of an unknown sample.

[0074] In the internal standard method, standard samples containing the target compound and an internal standard substance different from the target compound, each prepared at a known concentration, are analyzed, a calibration curve is prepared in advance based on the area or height of each peak, and the measured value is calculated from the value of the peak area or height in the analysis results of an unknown sample to which a known concentration of the internal standard substance has been added.

[0075] In the present invention, the quantitative value of glycyrrhizinate may be a value determined using, for example, an external standard method (absolute calibration curve method) of liquid chromatography.

[0076] As used herein, "an increase in the quantitative value of glycyrrhizinate" refers to an increase in the quantitative value after a sheet substrate is impregnated with a composition containing glycyrrhizinate. The increase in the quantitative value of glycyrrhizinate may be an increase in the quantitative value immediately after the sheet substrate is impregnated with the composition containing glycyrrhizinate, or may be an increase in the quantitative value after a certain period of time has passed since impregnation. The increase in the quantitative value of glycyrrhizinate may be, for example, an increase in the quantitative value that occurs when the composition containing glycyrrhizinate comes into contact with the sheet substrate, preferably a nonwoven fabric. "The composition comes into contact with the sheet substrate" includes the composition impregnating the sheet substrate with the sheet substrate.

[0077] An increase in the quantitative value of glycyrrhizinate is not particularly limited, but may mean, for example, that the quantitative value of glycyrrhizinate is greater than the blended amount of glycyrrhizinate, such as 101% or more, 102% or more, 103% or more, or 104% or more of the blended amount of glycyrrhizinate. An increase in the quantitative value of glycyrrhizinate may also mean that the quantitative value of glycyrrhizinate exceeds the upper limit of the content specification range. For example, if the upper limit of the content specification for glycyrrhizinate is 110% of the blended amount (labeled amount), an increase in the quantitative value of glycyrrhizinate may mean that the quantitative value exceeds 110% of the blended amount (labeled amount).

[0078] As used herein, "suppressing an increase in the quantitative value of glycyrrhizinate" means suppressing the "increase in the quantitative value of glycyrrhizinate" described above. That is, suppressing an increase in the quantitative value of glycyrrhizinate may mean suppressing an increase in the quantitative value of glycyrrhizinate beyond the blended amount of glycyrrhizinate, or suppressing an increase in the quantitative value of glycyrrhizinate to less than 101%, 102%, 103%, or 104%, for example, of the blended amount of glycyrrhizinate. Furthermore, suppressing an increase in the quantitative value of glycyrrhizinate may mean suppressing the quantitative value of glycyrrhizinate from exceeding the upper limit of the content specification range. For example, if the upper limit of the content specification for glycyrrhizinate is 110% of the blended amount (labeled amount), suppressing an increase in the quantitative value of glycyrrhizinate may mean suppressing the quantitative value from exceeding 110% of the blended amount (labeled amount).

[0079] In the production method and method of the present invention, the preparation of the composition containing glycyrrhizinate (A) and buffer (B) and maintained at a pH of 5.0 to 7.5 by buffer (B) is not particularly limited and can be prepared according to a conventional method. For example, the composition may be prepared by mixing an aqueous solution of glycyrrhizinate with a buffer solution prepared by dissolving a buffer in water to adjust the pH.

[0080] In the manufacturing method and method of the present invention, the step of impregnating the sheet substrate with the composition is not particularly limited and can be carried out according to a conventional method. This step may include, for example, at least one or all of the following steps (1) to (3): (1) placing the sheet substrate in a container; (2) filling the composition into a container; (3) Sealing the container.

[0081] Either step (1) or step (2) may be performed first. The method for placing the sheet substrate in the container and the method for filling the container with the composition are not particularly limited, and known methods can be used. Furthermore, the manufacturing method and method of the present invention are not limited to the above-mentioned methods. For example, the sheet substrate may be impregnated with the composition outside the container, and then the sheet substrate may be placed in the container.

[0082] In step (3), the container can be sealed using any method depending on the type and material of the container, for example, heat sealing. [Example]

[0083] In the following examples, dipotassium glycyrrhizinate (GK2) was used as the glycyrrhizinate, but the present invention is not limited thereto. In the following examples, the quantitative value of GK2 is also simply referred to as "GK2 content."

[0084] (GK2 content measurement method) The analytical conditions for GK2 content are shown below. Liquid chromatography equipment: Shimadzu Prominence 20AD-vp Detector: Ultraviolet absorption photometer (UV) Detection wavelength: 254 nm Column: A stainless steel tube with an inner diameter of 4.6 mm and a length of 15 to 25 cm is packed with 5 μm octadecylsilanized silica gel for liquid chromatography. Column temperature: constant temperature of 40°C Mobile phase: Water / acetonitrile / acetic acid (100) mixture Flow rate: 1.0 mL / min Injection volume: 10μL

[0085] The peak area of ​​the sample solution was measured using the absolute calibration curve method of liquid chromatography, and the GK2 content was determined based on a previously prepared calibration curve. The GK2 content in the 0.1% GK2 aqueous solution before impregnation into the nonwoven fabric or gauze was also measured, and any change (increase or decrease) in the GK2 content after impregnation compared to before impregnation was investigated.

[0086] (Calibration curve creation method) A 0.1% aqueous solution of GK2 was accurately prepared and used as the standard stock solution. Standard stock solutions 1, 2, 3, and 4 mL were diluted to 25 mL with a 49:1 mixture of methanol and acetic acid (100%) to prepare the standard solutions. Liquid chromatography was performed under the above analytical conditions, and a calibration curve was created.

[0087] (pH measurement method) The electrodes of a pH meter (HORIBA F-72; electrode 9615S-10D) were placed in direct contact with the sample solution, and the pH was measured once the reading had stabilized.

[0088] (Method for measuring pH of nonwoven fabric and gauze) Each nonwoven fabric and gauze was cut into 2g pieces, placed in an aluminum pouch, and 20ml of water was poured into each pouch using a measuring pipette. The aluminum pouch was sealed using a heat sealer and left to stand flat for 10 minutes. The pouch was squeezed from the top, and the squeezed liquid was collected in a glass bottle. The pH of each squeezed liquid was measured using the method described above.

[0089] [Test 1: Test using 12 types of nonwoven fabric and gauze] (0.1% GK2 aqueous solution) 2.0 g of dipotassium glycyrrhizinate was weighed out and diluted with water to a total volume of 2 L. Since dipotassium glycyrrhizinate has a purity of 98.8%, strictly speaking it is a 0.0988% aqueous solution, but hereafter it will be referred to as "0.1%."

[0090] (Test Method) When investigating the number of nonwoven fabrics and the amount of impregnation liquid per package for typical medium- and large-volume individually packaged sheet masks, the average amount of impregnation liquid per 1 g of nonwoven fabric was approximately 10 mL. Therefore, 2 g of nonwoven fabric or gauze was impregnated with 20 mL of 0.1% GK2 aqueous solution (hereinafter referred to as "GK2 impregnation liquid" or "impregnation liquid"), and the liquid was squeezed out to prepare a sample solution.

[0091] Specifically, nonwoven fabric or gauze was cut into 2 g pieces, placed in an aluminum pouch, poured with 20 mL of 0.1% GK2 aqueous solution, sealed with a heat sealer, and left to stand flat for 1 hour. After 1 hour, the nonwoven fabric or gauze was squeezed from the top of the aluminum pouch, and the squeezed liquid was collected. 1.0 g of the squeezed liquid was made up to 10 mL with a methanol / acetic acid (100) mixture (49:1). This liquid was filtered through a membrane filter, and the filtrate was used as the sample solution.

[0092] Twelve types of nonwoven fabrics and gauzes (No. 1 to 12) were selected, each with a different material and thickness (see Table 1). Each nonwoven fabric and gauze was impregnated with a 0.1% GK2 aqueous solution (impregnation solution) to prepare a sample solution, and the change in GK2 content and pH were measured (n=2). Table 1 shows the pH and GK2 content of each nonwoven fabric and gauze, as well as the pH of the solution squeezed out of the GK2 impregnation solution added to each nonwoven fabric and gauze. Table 1 also shows the change in GK2 content and pH after impregnation, compared to when the nonwoven fabric and gauze were not impregnated with the GK2 impregnation solution.

[0093] [Table 1]

[0094] Of the 12 types of nonwoven fabrics and gauzes, the GK2 content of nine types of nonwoven fabrics (No. 1 to No. 9) increased after impregnation with a 0.1% GK2 aqueous solution (impregnation solution) compared to the unimpregnated GK2 impregnation solution. Furthermore, the pH of the squeezed solution added to these nonwoven fabrics increased compared to the unimpregnated GK2 impregnation solution. The pH of these nine types of nonwoven fabrics was nearly neutral (pH 6.0 to 6.9).

[0095] On the other hand, the GK2 content of the No. 10 nonwoven fabric, which is composed of a layered structure of pulp and rayon, decreased after being impregnated with a 0.1% GK2 aqueous solution. The pH of the No. 10 nonwoven fabric was around 5, which was almost the same as the pH of the 0.1% GK2 aqueous solution. Therefore, it was thought that maintaining the pH when the nonwoven fabric was impregnated with the 0.1% GK2 aqueous solution was important in suppressing the increase in the GK2 content.

[0096] [Test 2: pH 3-9 buffer solution] (Preparation of pH 3 to 7 buffer solutions) Using citric acid and sodium citrate as buffering agents, buffer solutions of pH 3, 4, 5, 6, and 7 were prepared.

[0097] A 0.1 mol / L aqueous solution of citric acid (compliant with quasi-drug raw material standards; concentration 2.10%) and a 0.1 mol / L aqueous solution of sodium citrate (compliant with quasi-drug raw material standards; concentration 2.94%) were prepared in advance as stock buffer solutions.

[0098] These buffer stock solutions were mixed according to the formulations in Table 2, the pH was confirmed with a pH meter (HORIBA), and 300 mL of each solution was prepared. For the pH 7 buffer solution, 0.1 mol / mL citric acid solution was added dropwise to 270 mL of 0.1 mol / L sodium citrate solution, and when the pH reached 7, water was added to bring the total volume to 300 mL.

[0099] (How to prepare buffer solutions of pH 8 and 9) Buffer solutions of pH 8 and 9 were prepared using edetate disodium dihydrate and sodium hydroxide as buffering agents.

[0100] 800 mL of water was added to 186.1 g of edetate disodium dihydrate (compliant with quasi-drug raw material standards), and sodium hydroxide (special grade pharmaceutical, caustic soda (granular), Fujifilm Wako Pure Chemical Industries, Ltd.) was added. The mixture was stirred while checking with a pH meter until the edetate disodium dihydrate was completely dissolved and the pH was adjusted to 8.

[0101] Sodium hydroxide was added to 280 mL of this pH 8 buffer solution to adjust the pH to 9 while stirring, and water was added to make the total volume 300 mL.

[0102] [Table 2]

[0103] (Preparation method of GK2 aqueous solution) 2.5 g of GK2 was weighed and placed in a 250 mL measuring flask. Approximately 200 mL of water was added slowly, taking care not to create bubbles. Since GK2 does not dissolve immediately, it was placed in an ultrasonic cleaner for approximately 10 minutes to disperse it evenly. Then, the flask was filled up with water again to prepare a 1.0% GK2 aqueous solution.

[0104] (Test Method) A pH 3-9 buffer solution was added to 25 mL of 1.0% GK2 aqueous solution to make a total volume of 250 mL, to prepare an impregnation solution of pH 3-9 (hereinafter also referred to as "GK2-blended buffer solution") (0.1% GK2 concentration). 2 g of No. 2 nonwoven fabric (see Table 1) was placed in an aluminum pouch, and 20 mL of each GK2-blended buffer solution of pH 3-9 was added to impregnate the fabric. The pouch was sealed as in Test 1, and the pouch was left to stand flat for 1 hour. The squeezed liquid was then collected (n=2). The squeezed liquid was also collected when only the GK2-blended buffer solution was placed in the aluminum pouch without the nonwoven fabric (n=2).

[0105] 1.0 g of the squeezed liquid impregnated with GK2 blend buffers of pH 3 to 7 was diluted to 10 ml with a methanol / acetic acid (100) mixture (49:1). 1.0 g of the squeezed liquid impregnated with GK2 blend buffers of pH 8 and 9 was diluted to 10 ml with water because diluting with an organic solvent would cause the buffer to precipitate. These solutions were filtered through a membrane filter, and the filtrate was used as the sample solution.

[0106] The GK2 content and pH of each of these sample solutions were measured under the same conditions as in Test 1. The recovery rate was calculated as the ratio (%) of the GK2 content after impregnation to the GK2 content before impregnation. The GK2 content and recovery rate (%) are shown in Table 3. The pH measurement results are shown in Table 4.

[0107] [Table 3]

[0108] [Table 4]

[0109] When nonwoven fabric was impregnated with a non-buffered 0.1% GK2 aqueous solution, the recovery rate increased to approximately 106%. On the other hand, when impregnated with a GK2-blended buffer solution in the acidic range (pH 3, 4), the GK2 recovery rates significantly decreased to 60.4% and 83.9%, respectively. In the neutral range (pH 5, 6, 7), the recovery rate was near 100%, and the increase in GK2 content was suppressed in all cases. Furthermore, in the alkaline range (pH 8, 9), the recovery rates were 86.5% and 86.9%, respectively, indicating a decrease. These results suggest that maintaining the pH in the neutral range (pH 5, 6, 7) and suppressing pH fluctuations can suppress the increase in GK2 content in nonwoven fabrics.

[0110] Regarding pH, when impregnated with a 0.1% GK2 aqueous solution that has no buffering properties, the nonwoven fabric affected the pH, resulting in an increase in pH compared to when there was no nonwoven fabric. When impregnated with a GK2-blended buffer solution with a pH of 3 to 9, the pH remained nearly the same regardless of whether there was a nonwoven fabric or not, confirming that the nonwoven fabric has buffering properties.

[0111] [Test 3: Stability of GK2 content over time] Using a stability tester, the stability of GK2 content was compared when stored under accelerated conditions of 40°C and 75% Rh for up to 6 months (equivalent to 3 years at room temperature).

[0112] Aluminum pouches containing No. 2 nonwoven fabric (see Table 1) impregnated with the GK2-blended buffer solutions (pH 3-9) prepared in Test 2 were stored under accelerated conditions of 40°C and 75% RH for 3 or 6 months, and the squeezed liquid was collected (n=2). Sample solutions were prepared in the same manner as in Test 2, and the GK2 content and pH were measured. The ratio (%) of the GK2 content after impregnation to the GK2 content before impregnation was calculated as the recovery rate.

[0113] The GK2 content and recovery rate (%) after storage for 3 months under accelerated conditions are shown in Table 5, and the GK2 content and recovery rate (%) after storage for 6 months are shown in Table 6. In addition, the measurement results of pH after storage for 3 months under accelerated conditions are shown in Table 7, and the measurement results of pH after storage for 6 months are shown in Table 8.

[0114] [Table 5]

[0115] [Table 6]

[0116] [Table 7]

[0117] [Table 8]

[0118] Even after storage for 3 or 6 months under accelerated conditions, the GK2 content decreased in the presence of nonwoven fabric in the acidic range (pH 3, 4) and also in the alkaline range (pH 8, 9), as in Test 2 (1 hour standing). Meanwhile, in the neutral range (pH 5, 6, 7), the GK2 content remained constant regardless of the presence or absence of nonwoven fabric, and the recovery rate was nearly 100%. These results confirmed the stability of the GK2 content over time.

[0119] Regarding pH, when impregnated with a non-buffering 0.1% GK2 aqueous solution, the nonwoven fabric affected the pH, with an increase in pH observed at both 3 and 6 months compared to when the nonwoven fabric was not used. When impregnated with a GK2-blended buffer solution with a pH of 3 to 9, the pH remained roughly the same at both 3 and 6 months, regardless of whether the nonwoven fabric was used or not, confirming the pH stability of the buffer capacity over time.

[0120] [Test 5] We investigated whether the increase in GK2 content could be suppressed when nonwoven fabrics and gauze Nos. 1 to 12 shown in Table 1 were impregnated with a 0.1% GK2 aqueous solution (GK2-blended buffer solution) prepared using a citrate buffer solution of pH 6. Sample preparation and analysis conditions were the same as in Test 2.

[0121] Each nonwoven fabric and gauze were impregnated with a 0.1% GK2 aqueous solution (GK2 buffer solution) prepared using a citrate buffer solution of pH 6 to prepare a sample solution, and the change in GK2 content and pH were measured (n=2). The quantitative value of GK2 measured, the recovery rate of GK2, and pH are shown in Table 9.

[0122] [Table 9]

[0123] As shown in Table 9, by using a GK2-blended buffer solution prepared with a pH 6 buffer solution, the recovery rate of GK2 was nearly 100%, regardless of the nonwoven fabric or gauze used, demonstrating that the increase in GK2 content could be suppressed.

[0124] [Test 6] These test results suggest that the increase in GK2 content when nonwoven fabric is impregnated is due to the increase in pH caused by impregnation of the nonwoven fabric. It was also shown that the increase in GK2 content after impregnation of the nonwoven fabric can be suppressed by stabilizing the pH of the GK2 impregnation solution with a buffer solution of pH 5 to 7 before impregnating the nonwoven fabric.

[0125] Therefore, we investigated the range of buffer concentrations that can suppress the increase in GK2 content, using citrate buffer as a representative.

[0126] (Preparation method of GK2 aqueous solution) 5.0 g of GK2 was weighed and placed in a 500 mL measuring flask. Approximately 400 mL of water was added slowly, taking care not to create bubbles. Since GK2 does not dissolve immediately, it was placed in an ultrasonic cleaner and dispersed for approximately 10 minutes until it was uniformly dispersed. Then, the flask was again filled with water to prepare a 1.0% GK2 aqueous solution.

[0127] (How to prepare a buffer solution of pH 5 to 7) A 0.1 mol / L aqueous solution of citric acid (compliant with quasi-drug raw material standards; concentration 2.10%) and a 0.1 mol / L aqueous solution of sodium citrate (compliant with quasi-drug raw material standards; concentration 2.94%) were prepared in advance as stock buffer solutions.

[0128] These buffer stock solutions were mixed according to the blending ratios in Table 10, the pH was confirmed with a pH meter (HORIBA), and 300 mL of each solution was prepared. For the pH 7 buffer solution, 0.1 mol / mL citric acid solution was added dropwise to 270 mL of 0.1 mol / L sodium citrate solution, and when the pH reached 7, water was added to bring the total volume to 300 mL. The buffer solutions of pH 5, 6, and 7, prepared by blending two 0.1 mol / L solutions, were used as stock solutions and diluted 2-fold, 5-fold, 10-fold, and 20-fold with water, respectively. It was confirmed that the pH of these diluted solutions maintained the desired pH of 5, 6, and 7, respectively.

[0129] [Table 10]

[0130] (Preparation of GK2 buffer solution with pH 5-7) A 10 mL portion of the previously prepared 1.0% GK2 aqueous solution was placed in a 100 mL volumetric flask using a measuring pipette, and the volume was adjusted to 100 mL with each of the pH buffer solutions (stock solution and diluted solution).These were used as GK2-containing buffer solutions before impregnation (GK2-blended buffer solutions), and pH measurements were carried out.

[0131] (Test Method) Aluminum pouches containing 2 g of No. 2 nonwoven fabric (see Table 1) were impregnated with 20 mL of each GK2 blend buffer solution prepared using each pH buffer solution. All aluminum pouches were sealed with a heat sealer and left to stand flat for 1 hour. After 1 hour, the aluminum pouches were squeezed from the top and the squeezed liquid was collected. The pH of the impregnation liquid before and after impregnation was measured.

[0132] Next, 1.0 g of each squeezed liquid was collected, placed in a 10 mL volumetric flask, and made up to 100 mL with a methanol / acetic acid (100) mixture (49:1). This liquid was filtered through a membrane filter, and the filtrate was used as a sample solution for liquid chromatography. The GK2 content of each sample solution was measured under the same conditions as in Test 1. The ratio (%) of the GK2 content after impregnation to the GK2 content before impregnation was calculated as the recovery rate.

[0133] Figure 1 shows the measured pH values ​​for the stock and diluted solutions of each pH buffer, the GK2-blended buffer solutions prepared using these solutions, and the squeezed liquid after impregnation. The pH of the squeezed liquid after impregnation was the average of measurements obtained from two tests. From the stock (1x) to 2x dilutions of the citrate buffers at pH 5, 6, and 7, the pH of the buffer solution alone, the pH of the GK2-blended buffer solution containing 0.1% GK2 (before impregnation with nonwoven fabric), and the pH of the squeezed liquid after impregnation with nonwoven fabric were all stable. From 5x to 20x dilutions, pH fluctuations were observed, indicating that the buffering capacity was reduced due to the effects of GK2 or the nonwoven fabric.

[0134] Table 11 shows the quantitative GK2 values ​​and recovery rates when nonwoven fabric was impregnated with GK2-containing buffer solutions prepared using buffer solutions of various pH levels. From the original solution to 2-fold dilutions of citrate buffer solutions at pH 5, 6, and 7, the quantitative GK2 values ​​were around 0.1% and the recovery rates were around 100%, indicating that the increase in GK2 content was sufficiently suppressed. On the other hand, with 5- to 20-fold dilutions of the buffer solutions, both the quantitative GK2 values ​​and recovery rates increased, indicating that the increase in GK2 content was not sufficiently suppressed. These results correspond to the results of pH fluctuations shown in Figure 1.

[0135] These results suggest that the increase in GK2 content caused by nonwoven fabric can be sufficiently suppressed from the original solution to a 2-fold dilution of each buffer solution. Table 12 shows the amount and total amount of citric acid and sodium citrate used in each buffer solution, as well as whether or not they had an inhibitory effect on GK2 increase. An "○" indicates that an inhibitory effect on GK2 increase was observed, and an "×" indicates that no inhibitory effect was observed.

[0136] [Table 11]

[0137] [Table 12]

[0138] As shown in Table 12, it was found that the increase in GK2 content caused by nonwoven fabrics could be suppressed when using undiluted or 2-fold diluted 0.1 mol / L citrate buffer solutions at pH 5 to 7. The total amount of citric acid and sodium citrate used when GK2 increase was suppressed was in the range of 1.33 to 2.67% at pH 5, 1.43 to 2.87% at pH 6, and 1.47 to 2.94% at pH 7.

[0139] [Test 7] The inhibitory effect of succinate buffer and phosphate buffer on the increase of GK2 content was investigated. Succinic acid (succinic acid; Junsei Chemical Co., Ltd., quasi-drug raw material standard compliant product) and disodium succinate (disodium succinate hexahydrate; Junsei Chemical Co., Ltd., quasi-drug raw material standard compliant product) were used as buffering agents for the succinate buffer. Sodium monohydrogen phosphate (disodium hydrogen phosphate dodecahydrate; Junsei Chemical Co., Ltd., quasi-drug raw material standard compliant product) and sodium dihydrogen phosphate (sodium dihydrogen phosphate dihydrate; Junsei Chemical Co., Ltd., quasi-drug raw material standard compliant product) were used as buffering agents for the phosphate buffer.

[0140] For each of the two buffers, a stock solution of a fixed concentration was prepared, and the pH was adjusted using a pH meter by combining the two solutions to obtain the desired pH, thereby preparing buffer solutions of pH 5, pH 6, and pH 7.

[0141] As in Test 6, a 1.0% aqueous GK2 solution was prepared.

[0142] A 0.1 mol / L aqueous solution of succinic acid and a 0.1 mol / L aqueous solution of disodium succinate were prepared in advance as stock buffer solutions, and the two solutions were blended to give pH 5, pH 6, and pH 7 to prepare succinate buffer solutions. A 0.2 mol / L aqueous solution of sodium monohydrogen phosphate and a 0.2 mol / L aqueous solution of sodium dihydrogen phosphate were also prepared as stock buffer solutions, and the two solutions were blended similarly to give pH 5, pH 6, and pH 7 to prepare phosphate buffer solutions. The pH of each solution was measured using the method described above.

[0143] A 10 mL portion of the previously prepared 1.0% GK2 aqueous solution was placed in a 100 mL volumetric flask using a measuring pipette, and the volume was adjusted to 100 mL with each of the pH buffer solutions (stock solution and diluted solution).These were used as GK2-containing buffer solutions before impregnation (GK2-blended buffer solutions), and pH measurements were carried out.

[0144] Using the same method as in Test 6, nonwoven fabric No. 2 was impregnated with a GK2-blended buffer solution, and the pH of the impregnation solution before impregnation and the squeezed solution after impregnation were measured. A sample solution for liquid chromatography was also prepared, and the GK2 content was measured under the same conditions as in Test 1. The ratio (%) of the GK2 content after impregnation to the GK2 content before impregnation was calculated as the recovery rate.

[0145] The pH of each buffer solution prepared, as well as the pH of the GK2-containing buffer solution before and after impregnation of the nonwoven fabric, are shown in Table 13. The pH after impregnation of the nonwoven fabric was measured twice and the average value was calculated. The GK2-containing buffer solution of each pH remained stable even after impregnation of the nonwoven fabric, demonstrating sufficient buffering capacity.

[0146] The GK2 content and recovery rate when nonwoven fabric was impregnated with each GK2-blended buffer solution are shown in Table 14. The GK2 content when nonwoven fabric was impregnated with each GK2-blended buffer solution is shown in Figure 2.

[0147] [Table 13]

[0148] [Table 14]

[0149] The inhibitory effect of nonwoven fabrics on the increase in GK2 content was confirmed not only with citrate buffer but also with other types of buffers. As shown in Table 14 and Figure 2, when a 0.1% GK2 aqueous solution with no buffering capacity was used, the GK2 content of nonwoven fabric (No. 2) increased by approximately 5% after impregnation compared to before impregnation. On the other hand, when a 0.1% GK2 aqueous solution prepared with succinic acid and phosphate buffers (GK2-blended buffer) was used, the increase in GK2 content was sufficiently inhibited, being limited to 0.8 to 2.1% compared to before impregnation. [Industrial Applicability]

[0150] The present invention can be suitably used for sheet-type cosmetics impregnated with cosmetics containing glycyrrhizinate.

Claims

1. A sheet-type cosmetic preparation in which a sheet substrate is impregnated with a composition containing a glycyrrhizinate (A) and a buffer (B), The sheet-form cosmetic preparation has a pH of 4.5 to 7.5 maintained by the buffer (B).

2. 2. The sheet-form cosmetic according to claim 1, wherein the total content of the buffer (B) is 0.6% by mass or more.

3. 3. The sheet-form cosmetic preparation according to claim 1, wherein the buffer (B) is at least one selected from the group consisting of a combination of citric acid and a salt thereof, a combination of succinic acid and a salt thereof, and a combination of monohydrogen phosphate and dihydrogen phosphate.

4. 3. The sheet-form cosmetic according to claim 1, wherein the glycyrrhizinate (A) is dipotassium glycyrrhizinate.

5. 3. The sheet-type cosmetic according to claim 1, wherein the sheet substrate is a nonwoven fabric.

6. A method for producing a sheet-type cosmetic, comprising: A step of preparing a composition containing glycyrrhizinate (A) and a buffer (B), the pH of which is maintained by the buffer (B) at 5.0 to 7.5; and impregnating the composition into a sheet substrate. Manufacturing method of sheet-type cosmetic material

7. A method for suppressing an increase in the quantitative value of glycyrrhizinate in a sheet-type cosmetic, comprising: A step of preparing a composition containing glycyrrhizinate (A) and a buffer (B), the pH of which is maintained by the buffer (B) at 5.0 to 7.5; and impregnating the composition into a sheet substrate. method.

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