WO2024177022A1

WO2024177022A1 - Liquid composition for oral use

Info

Publication number: WO2024177022A1
Application number: PCT/JP2024/005862
Authority: WO
Inventors: 歩己宮本
Original assignee: 第一三共ヘルスケア株式会社
Priority date: 2023-02-20
Filing date: 2024-02-19
Publication date: 2024-08-29

Abstract

This liquid composition for oral use comprises component (a), which is at least one selected from the group consisting of tranexamic acid and salts thereof, and a component (b), which is a perfume, and fulfils at least one of conditions 1 and 2 below. Condition 1 is that the liquid composition further comprises a component (c), which is a surfactant having an HLB value of 13.0-20.0, where the mass ratio (c)/((a)+(b)) is at least 3.5. Condition 2 is that the color difference ΔE* is 0.0-2.5.

Description

Liquid oral composition

The present invention relates to a liquid oral composition.

A technique for incorporating a copper compound into an oral preparation is described in Patent Document 1 (JP 2010-189358 A).
The document describes (paragraph 0001) a technology relating to an oral composition having excellent effects in suppressing periodontal disease and bad breath, which contains specific amounts of copper gluconate and/or copper sulfate or hydrates thereof, allantoin or a derivative thereof, and a nonionic surfactant having an HLB value of 6 to 20 (claim 1).

JP 2010-189358 A

The inventors' research has revealed that liquid oral compositions containing flavorings discolor over time.

The present invention provides a technology that suppresses discoloration of liquid oral compositions over time.

According to the present invention, the following liquid oral composition and method for inhibiting discoloration of a liquid oral composition are provided.
[1] (a) at least one selected from the group consisting of tranexamic acid and salts thereof;
(b) A liquid oral composition containing a fragrance and satisfying at least one of the following conditions 1 and 2.
(Condition 1)
The following component (c):
(c) a surfactant having an HLB value of 13.0 or more and 20.0 or less,
The mass ratio (c)/((a)+(b)) of the content of the component (c) to the total content of the components (a) and (b) is 3.5 or more (Condition 2).
The color difference ΔE ^* measured by the following method and obtained by the following formula (I) is 0.0 or more and 2.5 or less (method)
The liquid oral composition is stored at 25°C and 60°C for 4 weeks, and the chromaticity coordinates of each sample are measured under the following conditions using a spectrophotometer in accordance with JIS Z 8722. Based on the measured values, chromaticity coordinates defined by the CIE 1976 L ^* a ^* b ^* color system are obtained, and the color difference ΔE ^* is calculated.
Measurement method type: Spectrophotometric color measurement method Color matching function type: X, Y, Z values Illuminant type for color measurement: D65 light source/viewing angle 10°
Geometric conditions of illumination and reception: transmission (0°:0°)
Wavelength: Measurement wavelength 380nm to 780nm, Measurement interval: 5nm
ΔE ^* = {(L ^* 2 - L ^* 1) ² + (a ^* 2 - a ^* 1) ² + (b ^* 2 - b ^* 1) ² } ^1/2 (I)
(In the above formula (I), (L ^* 1, a ^* 1, b ^* 1) and (L ^* 2, a ^* 2, b ^* 2) are chromaticity coordinates defined in the CIE1976 ^L* a ^* b ^* color system of the sample after storage at 25°C for 4 weeks and at 60°C for 4 weeks, respectively.)
[2] A liquid oral composition described in [1], which satisfies condition 1.
[3] Component (d): A liquid oral composition described in [1] or [2], further containing a copper compound.
[4] A liquid oral composition described in any one of [1] to [3], wherein when the liquid oral composition contains ethanol, the ethanol content in the liquid oral composition is 30% by mass or less.
[5] A liquid oral composition described in any one of [1] to [4], wherein the liquid oral composition does not contain ethanol, or the liquid oral composition contains ethanol and the ethanol content in the liquid oral composition is 5% by mass or less.
[6] A liquid oral composition described in any one of [1] to [5], wherein component (b) contains one or more selected from the group consisting of lavender oil, peppermint oil and bergamot oil.
[7] A liquid oral composition described in any one of [1] to [6], wherein component (c) includes one or more selected from the group consisting of polyoxyethylene hydrogenated castor oil, polyoxyethylene cetyl ether, polyoxyethylene behenyl ether and polyethylene glycol fatty acid esters.
[8] A liquid oral composition described in [1] or [2], which satisfies condition 2.
[9] The liquid oral composition described in [8], wherein Δb ^* measured by the above method and obtained by the following formula (II) is 0 or more and 3.0 or less.
Δb ^* = b ^* 2 - b ^* 1 (II)
[10] Further comprising ethanol,
A liquid oral composition described in [8] or [9], wherein the content of ethanol in the liquid oral composition is 15 mass% or less relative to the entire liquid oral composition.
[11] A liquid oral composition described in any one of [8] to [10], wherein component (b) is peppermint oil.
[12] Component (c): a liquid oral composition described in any one of [8] to [11], further containing a surfactant having an HLB value of 13.0 or more and 20.0 or less.
[13] Component (d): A liquid oral composition described in any one of [8] to [12], further containing a copper compound.
[14] A method for suppressing discoloration of a liquid oral composition, comprising incorporating into a liquid oral composition containing (a) at least one selected from the group consisting of tranexamic acid and its salts, and (b) a fragrance, component (c): a surfactant having an HLB value of 13.0 or more and 20.0 or less, so that the mass ratio (c)/((a)+(b)) of the content of component (c) to the total content of components (a) and (b) is 3.5 or more.

The present invention makes it possible to inhibit discoloration of a liquid oral composition over time.

Hereinafter, an embodiment of the present invention will be described. In the embodiment, the composition may contain each component alone or in combination of two or more kinds.
In this specification, the term "to" indicating a numerical range means "greater than or equal to" or "less than or equal to," and both end numerical values are included.

In this embodiment, the liquid oral composition contains the following components (a) and (b) and satisfies at least one of the following conditions 1 and 2.
(a) at least one selected from the group consisting of tranexamic acid and its salts; and (b) a fragrance. (Condition 1)
Component (c): A surfactant having an HLB value of 13.0 or more and 20.0 or less is further contained, and the mass ratio (c)/((a)+(b)) of the content of the component (c) to the total content of the components (a) and (b) is 3.5 or more (Condition 2)
The color difference ΔE ^* measured by the following method and obtained by the following formula (I) is 0.0 or more and 2.5 or less (method)
The liquid oral composition is stored at 25°C and 60°C for 4 weeks, and the chromaticity coordinates of each sample are measured under the following conditions using a spectrophotometer in accordance with JIS Z 8722. Based on the measured values, chromaticity coordinates defined by the CIE 1976 L ^* a ^* b ^* color system are obtained, and the color difference ΔE ^* is calculated.
Measurement method type: Spectrophotometric color measurement method Color matching function type: X, Y, Z values Illuminant type for color measurement: D65 light source/viewing angle 10°
Geometric conditions of illumination and reception: transmission (0°:0°)
Wavelength: Measurement wavelength 380nm to 780nm, Measurement interval: 5nm
ΔE ^* = {(L ^* 2 - L ^* 1) ² + (a ^* 2 - a ^* 1) ² + (b ^* 2 - b ^* 1) ² } ^1/2 (I)
(In the above formula (I), (L ^* 1, a ^* 1, b ^* 1) and (L ^* 2, a ^* 2, b ^* 2) are chromaticity coordinates defined in the CIE1976 ^L* a ^* b ^* color system of the sample after storage at 25°C for 4 weeks and at 60°C for 4 weeks, respectively.)

When a liquid oral composition contains components (a) and (b) and satisfies at least one of conditions 1 and 2, discoloration over time can be effectively suppressed even when component (b) is contained.
In order to suppress discoloration over time, the liquid oral composition only needs to satisfy either condition 1 or 2, and preferably satisfies both.
Compositions that satisfy each of the conditions will be specifically described below. The configurations described in the following embodiments can be appropriately combined.

(First embodiment)
In this embodiment, the composition is applied to the oral cavity, and is specifically a liquid oral composition.

(Liquid oral composition)
In the present embodiment, the liquid oral composition contains the following components (a) to (c). That is, the liquid oral composition in the present embodiment satisfies the above-mentioned condition 1.
(a) at least one selected from the group consisting of tranexamic acid and its salts; (b) a fragrance; (c) a surfactant having an HLB value of 13.0 or more and 20.0 or less; and The mass ratio (c)/((a)+(b)) of the content of component (c) to the total content of components (a) and (b) is 3.5 or more.

The liquid oral composition in this embodiment contains a combination of the above-mentioned components (a) to (c) in a specific ratio, which effectively suppresses discoloration over time.
Each component will be described below.

(Component (a))
Component (a) is at least one selected from the group consisting of tranexamic acid and its salts. Component (a) is a known compound and can be produced by a known method, or a commercially available product can be used.

Component (a) is listed, for example, as tranexamic acid in the 18th edition of the Japanese Pharmacopoeia.
Specific examples of the salt of tranexamic acid include one or more salts selected from the group consisting of acid addition salts, metal salts, amine salts and salts with amino acids.
Among these, examples of acid addition salts include hydrohalides such as hydrofluorides, hydrochlorides, hydrobromides, and hydroiodides;
Inorganic acid salts such as nitrates, perchlorates, sulfates, and phosphates;
lower (C1 to C3) alkanesulfonates such as methanesulfonate, trifluoromethanesulfonate, and ethanesulfonate;
and one or more selected from the group consisting of arylsulfonates such as benzenesulfonate and p-toluenesulfonate; and organic acid salts such as acetate, malate, fumarate, succinate, citrate, ascorbate, tartrate, oxalate, and maleate.
Examples of the metal salt include one or more selected from the group consisting of alkali metal salts such as sodium salts and potassium salts; and alkaline earth metal salts such as calcium salts and magnesium salts.
Examples of the amine salt include organic amine salts such as N-methylmorpholine salt, triethylamine salt, tributylamine salt, diisopropylethylamine salt, dicyclohexylamine salt, N-methylpiperidine salt, pyridine salt, 4-pyrrolidinopyridine salt and picoline salt.
Furthermore, examples of salts with amino acids include one or more salts selected from the group consisting of glycine salts, lysine salts, arginine salts, ornithine salts, glutamic acid salts and aspartic acid salts.
From the standpoint of more stably suppressing discoloration of the liquid oral composition, component (a) is preferably tranexamic acid.

In order to exhibit better anti-inflammatory and anti-hemostatic effects, the content of component (a) in the liquid oral composition is preferably 0.01 mass% or more, more preferably 0.02 mass% or more, and even more preferably 0.03 mass% or more, of the entire liquid oral composition.
In addition, from the viewpoint of minimizing the impact on the experience of use, such as taste, the content of component (a) in the liquid oral composition is preferably 1 mass% or less, more preferably 0.5 mass% or less, even more preferably 0.1 mass% or less, and even more preferably 0.08 mass% or less, of the entire liquid oral composition.

(Component (b))
Component (b) is a fragrance.
Specific examples of component (b) include one or more selected from the group consisting of lavender oil, peppermint oil, bergamot oil, menthol, peppermint, spearmint and fruit flavorings. From the viewpoint of more stably suppressing discoloration of the liquid oral composition, component (b) preferably includes one or more selected from the group consisting of lavender oil, peppermint oil and bergamot oil.

In order to provide a good usability, the content of component (b) in the liquid oral composition is preferably 0.01 mass% or more, more preferably 0.03 mass% or more, even more preferably 0.05 mass% or more, and even more preferably 0.08 mass% or more, of the entire liquid oral composition.
In addition, from the viewpoint of reducing the influence on the feeling of use such as taste, the content of component (b) in the liquid oral composition is preferably 1% by mass or less, more preferably less than 1% by mass, even more preferably 0.5% by mass or less, and even more preferably 0.3% by mass or less, based on the entire liquid oral composition. On the other hand, from the viewpoint of providing a suitable fragrance, it is also preferable that the content of component (b) in the liquid oral composition is less than 1% by mass based on the entire liquid oral composition.

(Component (c))
The component (c) is a surfactant having an HLB value of 13.0 or more and 20.0 or less. Specific examples of such surfactants include nonionic surfactants.

Examples of nonionic surfactants include one or more selected from the group consisting of polyoxyethylene alkyl ethers such as polyoxyethylene cetyl ether and polyoxyethylene behenyl ether; polyoxyethylene-polyoxypropylene block copolymers; polyoxyethylene hydrogenated castor oil; polyoxyethylene ethers of glycerin esters; sucrose fatty acid esters; alkylol amides; glycerin fatty acid esters; and polyoxyalkylene fatty acid esters such as polyethylene glycol fatty acid esters.
When component (c) contains a polyoxyethylene chain, the average number of moles of ethylene oxide added is, for example, 50 to 100.
When component (c) contains an alkyl or fatty acid, the average number of moles of ethylene oxide added is, for example, 5 to 50, and preferably 9 to 50. The number of carbon atoms in the alkyl or fatty acid is, for example, 4 to 34, and preferably 12 to 22.

From the viewpoint of more stably suppressing discoloration of the liquid oral composition, component (c) is preferably a nonionic surfactant, and more preferably contains one or more selected from the group consisting of polyoxyethylene hydrogenated castor oil, polyoxyethylene cetyl ether, polyoxyethylene behenyl ether, and polyethylene glycol fatty acid ester.

The HLB value of component (c) is specifically 13.0 or more, and preferably 15.0 or more, from the standpoint of improving its solubility in water and more stably suppressing discoloration of the liquid oral composition.
The HLB value of component (c) is specifically 20.0 or less, preferably 19.0 or less, and more preferably 17.0 or less.
Here, when the liquid oral composition contains two or more surfactants, the HLB value can be calculated as the sum of the products of the HLB values and mass fractions of each surfactant.

The content of component (c) in the liquid oral composition is preferably 0.1 mass% or more, more preferably 0.5 mass% or more, even more preferably 0.8 mass% or more, still more preferably 1 mass% or more, and even more preferably 1.5 mass% or more, of the entire liquid oral composition, from the viewpoint of more stably solubilizing the oily components and more stably suppressing discoloration of the liquid oral composition.
In addition, from the viewpoint of suppressing bitterness and astringency and adjusting the taste, the content of component (c) in the liquid oral composition is preferably 10 mass% or less, more preferably 7.5 mass% or less, and even more preferably 5 mass% or less, of the entire liquid oral composition.

The mass ratio (c)/((a)+(b)) of the content of component (c) to the total content of components (a) and (b) is specifically 3.5 or more, preferably 4.0 or more, more preferably 4.5 or more, even more preferably 5.0 or more, and even more preferably 5.5 or more, from the standpoint of suppressing discoloration of the liquid oral composition over time.
In addition, from the viewpoint of suppressing bitterness and astringency and adjusting the taste, the mass ratio (c)/((a)+(b)) is preferably 50 or less, more preferably 40 or less, even more preferably 30 or less, and even more preferably 20 or less.

The liquid oral composition may contain components other than components (a) to (c).
For example, the liquid oral composition may further comprise component (d): a copper compound.

(Component (d))
Component (d) is a copper compound. The liquid oral composition further contains component (d), which can improve the effect of suppressing bad breath. Specific examples of component (d) include water-soluble copper salts.
Specifically, the water-soluble copper salt refers to a water-soluble copper salt among inorganic acid salts of copper and organic acid salts of copper. The water-soluble copper salt may be either anhydrous or hydrated. The water-soluble copper salt may be any of those usable as raw materials for pharmaceuticals, foods, or cosmetics.
Examples of the water-soluble copper salt include one or more selected from the group consisting of copper gluconate, copper sulfate, copper citrate, copper chlorophyll, and sodium copper chlorophyllin. From the viewpoint of further improving the blending effect of the water-soluble copper salt, such as the effect of suppressing bad breath, the water-soluble copper salt preferably includes at least one of copper gluconate and copper sulfate, and more preferably copper gluconate.
As the water-soluble copper salt, for example, a commercially available product can be used.

The content of component (d) in the liquid oral composition is preferably 0.001 mass% or more, more preferably 0.01 mass% or more, even more preferably 0.03 mass% or more, and more preferably 0.08 mass% or more, relative to the entire liquid oral composition, in order to further improve the blending effect of the water-soluble copper salt, such as the bad breath suppression effect.
In addition, from the viewpoint of reducing unpleasant usage sensations such as a metallic taste, the content of component (d) in the liquid oral composition is preferably 10 mass% or less, more preferably 1 mass% or less, even more preferably 0.5 mass% or less, even more preferably 0.3 mass% or less, and even more preferably 0.2 mass% or less, relative to the entire liquid oral composition.

In addition, the content of component (d) in the liquid oral composition is preferably 0.001 mass% or more, and more preferably 0.01 mass% or more, in terms of the amount of copper, from the viewpoint of further improving the blending effect of component (d), such as the bad breath suppression effect.
In addition, from the standpoint of reducing unpleasant usage sensations such as a metallic taste, the content of component (d) in the liquid oral composition is preferably 0.06 mass% or less, and more preferably 0.03 mass% or less, in terms of the copper content.

The mass ratio (c)/((a) + (b) + (d)) of the content of component (c) to the total content of components (a), (b) and (d) is preferably 2.6 or more, more preferably 3.0 or more, and even more preferably 5.0 or more, in order to suppress discoloration of the liquid oral composition over time.
In addition, from the viewpoint of suppressing bitterness and astringency and adjusting the taste, the mass ratio (c)/((a)+(b)+(d)) is preferably 50 or less, more preferably 40 or less, even more preferably 30 or less, and even more preferably 20 or less.

(water)
Liquid oral compositions specifically contain water.
The water content in the liquid oral composition can be, for example, the remainder after excluding components other than water in the liquid oral composition.
In addition, the water content in the liquid oral composition is preferably 50% by mass or more, more preferably 60% by mass or more, even more preferably 70% by mass or more, and preferably 99.88% by mass or less, more preferably 99.5% by mass or less, and even more preferably 99% by mass or less, based on the entire liquid oral composition.

(ethanol)
The liquid oral composition may further contain ethanol.
The ethanol content in the liquid oral composition is preferably 0.1 mass% or more, more preferably 1 mass% or more, and even more preferably 2 mass% or more, in order to provide a moderately refreshing and pleasant feel when used.
In addition, from the viewpoint of suppressing strong irritation to the oral cavity, the content of ethanol in the liquid oral composition is preferably 30% by mass or less, more preferably 20% by mass or less, even more preferably 10% by mass or less, even more preferably 7.5% by mass or less, and even more preferably 5% by mass or less. From the same viewpoint, it is also preferable that the liquid oral composition does not contain ethanol, that is, the content of ethanol is 0% by mass, or the liquid oral composition contains ethanol and the content of ethanol is 5% by mass or less.

(Other ingredients)
Compositions such as liquid oral compositions may contain components other than the above-mentioned components, as long as the effects of the present invention are not impaired.
Such ingredients include, for example, medicinal ingredients, binders, wetting agents, flavoring agents, preservatives, colorants, pH adjusters, solvents, solubilizers, bases, detergents, adsorbents, etc., and may be appropriately selected depending on the dosage form. Specific examples of additive ingredients are shown below, but the ingredients that can be added in the present invention are not limited to these.

The medicinal components include, for example, one or more selected from the group consisting of bactericides, anti-inflammatory agents, blood circulation promoters, tartar deposition inhibitors, stain removers, dentin hypersensitivity inhibitors, vitamins, and plaque decomposing enzymes. There are no limitations on these medicinal components as long as they can be used in medicines, etc.

Among the medicinal ingredients, examples of the bactericide include one or more selected from the group consisting of isopropylmethylphenol, cetylpyridinium chloride, benzalkonium chloride, benzethonium chloride, hinokitiol, chlorhexidine hydrochloride, alkyldiaminoethylglycine hydrochloride, sodium lauroyl sarcosine, and triclosan.

Examples of anti-inflammatory agents include one or more selected from the group consisting of β-glycyrrhetinic acid, glycyrrhetinic acid, glycyrrhizinic acid, diammonium glycyrrhizinate, disodium glycyrrhizinate, trisodium glycyrrhizinate, dipotassium glycyrrhizinate, monoammonium glycyrrhizinate, ε-aminocaproic acid, sodium azulene sulfonate hydrate, allantoin, allantoin dihydroxyaluminum, epidihydrocholesterol, dihydrocholesterol, and lysozyme hydrochloride.

An example of a blood circulation promoter is sodium chloride.

Examples of tartar deposition inhibitors include one or more selected from the group consisting of disodium hydrogen phosphate, disodium dihydrogen pyrophosphate, sodium pyrophosphate, anhydrous sodium pyrophosphate, tetrasodium pyrophosphate (anhydrous), disodium monohydrogen phosphate, sodium hydrogen phosphate hydrate, disodium hydrogen phosphate (crystalline), trisodium phosphate, and sodium polyphosphate.

Stain removers include, for example, one or more selected from the group consisting of macrogol (Macrogol 200, Macrogol 300, Macrogol 400, Macrogol 600, Macrogol 1000, Macrogol 1500, Macrogol 1540, Macrogol 4000, Macrogol 6000, Macrogol 20000, etc.), sodium polyphosphate, and polyvinylpyrrolidone.

The dentin hypersensitivity suppressant may be, for example, at least one selected from the group consisting of potassium nitrate and water-soluble aluminum salts.

Examples of vitamin preparations include one or more selected from the group consisting of ascorbic acid, L-ascorbic acid, sodium ascorbate, L-sodium ascorbate, pyridoxine hydrochloride, DL-α-tocopherol acetate, tocopherol acetate, dl-α-tocopherol nicotinate, and tocopherol nicotinate.

An example of a plaque-decomposing enzyme is dextranase.

The binder may be one or more selected from the group consisting of organic binders such as pullulan, gelatin, methylcellulose, hydroxyethylcellulose, hydroxypropylcellulose, sodium carboxymethylcellulose, carrageenan, sodium alginate, xanthan gum, sodium polyacrylate, gum arabic, guar gum, locust bean gum, polyvinyl alcohol, and carboxyvinyl polymer, thickening anhydrous silicic acid, and bentonite.

Here, from the viewpoint of making it easier to rinse the oral cavity, it is preferable that the liquid oral composition does not contain xanthan gum, and it is more preferable that it does not contain a binder.
Here, the liquid oral composition not containing xanthan gum or a binder means, specifically, that xanthan gum or a binder has not been intentionally blended into the liquid oral composition, and more specifically, that the content of xanthan gum or a binder is 0.001 mass% or less of the entire liquid oral composition.

Humectants may be any that are commercially available as pharmaceutical, food, or cosmetic ingredients, such as polyhydric alcohols, and more specifically, one or more selected from the group consisting of sorbitol, glycerin, concentrated glycerin, ethylene glycol, propylene glycol, 1,3-butylene glycol, propanediol (1,3-propanediol), polyethylene glycol, polypropylene glycol, sodium hyaluronate, and hydrolyzed collagen.

From the viewpoint of reducing irritation to the oral cavity, the humectant is preferably at least one selected from the group consisting of glycerin and propylene glycol, and more preferably glycerin.
The content of humectant in the liquid oral composition is preferably 1% by mass or more, more preferably 3% by mass or more, even more preferably 5% by mass or more, and preferably 30% by mass or less, more preferably 25% by mass or less, and even more preferably 20% by mass or less, in order to make the viscosity of the liquid oral composition more favorable.

Flavoring agents include, for example, one or more selected from the group consisting of L-sodium glutamate, saccharin, saccharin sodium, sucrose, glucose, fructose, lactose, honey, aspartame, stevia, sucralose, inositol, D-sorbitol, D-mannitol, arabitol, raffinose, lactulose, lactitol, xylitol, erythritol, reduced palatinose, palatinose, Palatinit (registered trademark), acesulfame K, trehalose, maltose, maltosyl trehalose or maltitol, neohesperidin dihydrochalcone, perillartine, p-methoxycinnamic aldehyde, and thaumatin.

From the viewpoint of having a strong sweetness and being able to adjust the taste even with a small amount, the flavoring agent is preferably at least one selected from the group consisting of xylitol, sodium saccharin, and saccharin, and more preferably at least one selected from the group consisting of xylitol and sodium saccharin.
In order to provide a moderately refreshing and pleasant feel, the content of the flavoring agent in the liquid oral composition is preferably 0.01 mass% or more, more preferably 0.05 mass% or more, even more preferably 0.1 mass% or more, and preferably 2 mass% or less, more preferably 1 mass% or less, and even more preferably 0.5 mass% or less.

The preservative may be, for example, one or more selected from the group consisting of paraoxybenzoic acid esters such as sodium benzoate, methylparaben, ethylparaben, butylparaben, isopropylparaben, propylparaben, isobutylparaben, and benzylparaben; alcohols such as phenoxyethanol; sorbic acid, benzoic acid, dehydroacetic acid, propionic acid, and salts thereof; ethylenediaminetetraacetate; and alkyldiaminoethylglycine hydrochloride.

Coloring agents include, for example, one or more of the following natural dyes: safflower red, gardenia yellow, gardenia blue, perilla, red koji, red cabbage, carrot, hibiscus, cacao, spirulina blue, coumarind; legal dyes: Red No. 3, Red No. 104, Red No. 105, Red No. 106, Yellow No. 4, Yellow No. 5, Green No. 3, Blue No. 1; riboflavin, and titanium dioxide.

The pH adjuster may be, for example, one or more selected from the group consisting of acids, alkalis, and buffers, such as acetic acid, hydrochloric acid, sulfuric acid, nitric acid, citric acid, phosphoric acid, malic acid, gluconic acid, maleic acid, succinic acid, glutamic acid, pyrophosphoric acid, tartaric acid, sodium hydroxide acetate, potassium hydroxide, sodium acetate, sodium carbonate, sodium citrate, sodium hydrogen citrate, phosphoric acid, sodium phosphate, sodium monohydrogen phosphate, sodium dihydrogen phosphate, and potassium dihydrogen phosphate.

In addition to the water mentioned above, examples of the solvent include lower alcohols such as propanol.

　Solubilizers may be added to promote the dissolution of the additives and medicinal ingredients in water. Examples of such solubilizers include polyhydric alcohols such as dipropylene glycol.

An example of a base is sodium bicarbonate.

An example of a cleaning agent is sodium polyphosphate.

An example of an adsorbent is β-cyclodextrin.

Furthermore, in addition to the above-mentioned components, components generally suitable for use in oral compositions such as liquid oral compositions can also be appropriately blended within the scope of the present invention.

(viscosity)
In this embodiment, the viscosity of the liquid oral composition is preferably 25 mPa·s or less, more preferably 10 mPa·s or less, and even more preferably 7.5 mPa·s or less, from the standpoint of making it easier to rinse the oral cavity.
The viscosity of the liquid oral composition may also be, for example, 0.1 mPa·s or more.
Here, the viscosity of the liquid oral composition is specifically measured using a B-type viscometer (e.g., a Brookfield rotational viscometer DV3T, manufactured by Brookfield) under conditions of room temperature of 25±3°C, rotor LV-1, rotation speed of 200 rpm, and measurement time of 1 minute.

(Liquid formulation)
The liquid oral composition is specifically a liquid preparation. The liquid preparation is specifically a preparation for oral administration.
A specific embodiment of the liquid oral composition is one selected from the group consisting of a mouthwash, a liquid toothpaste, and a mouth freshener. The liquid oral composition is preferably a mouthwash.

(Production method)
In this embodiment, the liquid oral composition includes a step of blending, for example, components (a) to (c) and other components as appropriate.

The liquid oral composition obtained in this embodiment contains a combination of components (a) to (c) in a specific ratio, which effectively prevents discoloration over time.

(Method of inhibiting discoloration)
In this embodiment, the method for suppressing discoloration of a liquid oral composition includes blending the above-mentioned component (c) into a liquid oral composition containing the above-mentioned components (a) and (b) such that the mass ratio (c)/((a)+(b)) of the content of component (c) to the total content of components (a) and (b) is 3.5 or more. In the method of this embodiment, components (a) to (c) are combined in a specific ratio and blended into the liquid oral composition, so that discoloration of the liquid oral composition over time is suitably suppressed.

Second Embodiment
In this embodiment, the composition is applied to the oral cavity, and is specifically a liquid oral composition.

(Liquid oral composition)
In this embodiment, the liquid oral composition contains the following components (a) and (b).
(a) at least one selected from the group consisting of tranexamic acid and its salts; (b) a fragrance; and the color difference ΔE ^* of the liquid oral composition measured by the following method and obtained by the following formula (I) is: The liquid oral composition of the present embodiment satisfies the above-mentioned condition 2.
(method)
The liquid oral composition was stored at 25°C and 60°C for 4 weeks, and the chromaticity coordinates of each sample were measured under the following conditions using a spectrophotometer in accordance with JIS Z 8722. Chromaticity coordinates defined by the CIE1976L ^* a ^* b ^* color system are obtained, and the color difference ΔE ^* is calculated.
Measurement method type: Spectrophotometric color measurement method Color matching function type: X, Y, Z values Illuminant type for color measurement: D65 light source/viewing angle 10°
Geometric conditions of illumination and reception: transmission (0°:0°)
Wavelength: Measurement wavelength 380nm to 780nm, Measurement interval: 5nm
ΔE ^* = {(L ^* 2 - L ^* 1) ² + (a ^* 2 - a ^* 1) ² + (b ^* 2 - b ^* 1) ² } ^1/2 (I)
(In the above formula (I), (L ^* 1, a ^* 1, b ^* 1) and (L ^* 2, a ^* 2, b ^* 2) are the values obtained by aging at 25° C. for 4 weeks and 60° C. for 4 weeks, respectively.) The chromaticity coordinates of the sample after storage for one week are defined by the CIE1976L ^* a ^* b ^* color system.

The present inventors have newly discovered that the liquid oral composition contains the above components (a) and (b) and has a color difference ΔE ^* obtained by formula (I) within a specific range, thereby suitably suppressing discoloration over time. Specifically, the color difference ΔE ^* of the liquid oral composition after storage at 25° C. and after an accelerated test is used as an index of the presence or absence and degree of discoloration over time, and discoloration of the liquid oral composition can be effectively suppressed by setting this within a specific range.

The color difference ΔE ^* is specifically 0.0 or more, and from the viewpoint of suitably suppressing discoloration over time, it is preferably 0.01 or more, more preferably 0.05 or more, and even more preferably 0.1 or more.
In addition, from the viewpoint of suitably suppressing discoloration over time, the color difference ΔE ^* is specifically 2.5 or less, preferably 2.0 or less, more preferably 1.5 or less, even more preferably 1.0 or less, and even more preferably 0.8 or less. From the same viewpoint, the color difference ΔE ^* is even more preferably 0.5 or less.
From a similar standpoint, the color difference ΔE ^* may be 0.5 or less when the liquid oral composition does not contain a copper compound, and may be 2.5 or less when the liquid oral composition contains a copper compound.

The color difference ΔE ^* is measured by the above-mentioned method. More specifically, 50 mL of the liquid oral composition is dispensed into two 50 mL glass vials, one of which is stored under conditions of 25°C and 60% RH, and the other is stored in a thermostatic chamber at 60°C and normal humidity. Here, normal humidity is specifically within the range of relative humidity 45 to 85%.
After storage, each composition is allowed to return to room temperature by, for example, storing it at room temperature for 3 to 4 hours. Thereafter, the color of each composition is measured under the above-mentioned conditions using a spectrophotometer (specifically, SE-7700, manufactured by Nippon Denshoku Industries Co., Ltd.), and the color difference ΔE* is calculated from the lightness (L ^* ) and chromaticity (a ^* , b ^* ) defined in the CIE1976 L ^* a ^* b ^* color system according to formula (I ⁾ .

In the liquid oral composition, Δb ^* measured by the above-mentioned method and obtained by the following formula (II) is preferably 0 or more, preferably 0.01 or more, more preferably 0.05 or more, and even more preferably 0.1 or more, from the viewpoint of suitably suppressing discoloration over time.
From the viewpoint of suitably suppressing discoloration over time, the color difference Δb ^* is, for example, 3.0 or less, preferably 2.5 or less, more preferably 2.0 or less, even more preferably 1.5 or less, and even more preferably 1.0 or less. From the same viewpoint, the color difference Δb ^* is even more preferably 0.5 or less.
Δb ^* = b ^* 2 - b ^* 1 (II)

Next, we will explain the ingredients contained in the liquid oral composition.

In order to exhibit better anti-inflammatory and anti-hemostatic effects, the content of component (a) in the liquid oral composition is preferably 0.01 mass% or more, more preferably 0.02 mass% or more, and even more preferably 0.03 mass% or more, of the entire liquid oral composition.
In addition, from the viewpoint of minimizing the impact on the experience of use, such as taste, the content of component (a) in the liquid oral composition is preferably 1 mass% or less, more preferably 0.5 mass% or less, even more preferably 0.1 mass% or less, even more preferably less than 0.1 mass%, and even more preferably 0.08 mass% or less, of the entire liquid oral composition.

(Component (b))
Component (b) is a fragrance.
Specific examples of component (b) include one or more selected from the group consisting of lavender oil, peppermint oil, bergamot oil, menthol, peppermint, spearmint and fruit flavorings. From the viewpoint of more stably suppressing discoloration of the liquid oral composition, component (b) preferably includes one or more selected from the group consisting of lavender oil, peppermint oil and bergamot oil, more preferably peppermint oil.

In order to provide a good usability, the content of component (b) in the liquid oral composition is preferably 0.01 mass% or more, more preferably 0.03 mass% or more, even more preferably 0.05 mass% or more, even more preferably 0.1 mass% or more, and even more preferably 0.2 mass% or more, of the entire liquid oral composition.
In addition, from the viewpoint of reducing the influence on the feeling of use such as taste, the content of component (b) in the liquid oral composition is preferably 1% by mass or less, more preferably less than 1% by mass, even more preferably 0.5% by mass or less, and even more preferably 0.3% by mass or less, based on the entire liquid oral composition. On the other hand, from the viewpoint of providing a suitable fragrance, it is also preferable that the content of component (b) in the liquid oral composition is less than 1% by mass based on the entire liquid oral composition.

The liquid oral composition may contain components other than components (a) and (b).
For example, the liquid oral composition may further contain at least one of the following components (c) and (d).
(c) a surfactant having an HLB value of 13.0 or more and 20.0 or less; (d) a copper compound

(Component (c))
The component (c) is a surfactant having an HLB value of 13.0 or more and 20.0 or less. The liquid oral composition further contains the component (c), so that discoloration can be more stably suppressed. Specific examples of such surfactants include nonionic surfactants.

From the viewpoint of more stably suppressing discoloration of the liquid oral composition, component (c) is preferably a nonionic surfactant, more preferably contains one or more selected from the group consisting of polyoxyethylene hydrogenated castor oil, polyoxyethylene cetyl ether, polyoxyethylene behenyl ether and polyethylene glycol fatty acid ester, and even more preferably is polyoxyethylene hydrogenated castor oil.

The HLB value of component (c) is, for example, 13.0 or more, preferably 14.0 or more, and more preferably 15.0 or more, from the standpoint of improving its solubility in water and more stably suppressing discoloration of the liquid oral composition.
The HLB value of component (c) is, for example, 20.0 or less, preferably 19.0 or less, and more preferably 17.0 or less.
Here, when the liquid oral composition contains two or more surfactants, the HLB value can be calculated as the sum of the products of the HLB values and mass fractions of each surfactant.

The content of component (c) in the liquid oral composition is preferably 0.1 mass% or more, more preferably 0.5 mass% or more, even more preferably 0.8 mass% or more, still more preferably 1.0 mass% or more, and even more preferably 1.5 mass% or more, of the entire liquid oral composition, from the viewpoint of more stably solubilizing the oily components and more stably suppressing discoloration of the liquid oral composition.
In addition, from the viewpoint of suppressing bitterness and astringency and adjusting the taste, the content of component (c) in the liquid oral composition is preferably 10 mass% or less, more preferably 7.5 mass% or less, and even more preferably 5 mass% or less, of the entire liquid oral composition.

The mass ratio (c)/((a)+(b)) of the content of component (c) to the total content of components (a) and (b) is preferably 3.5 or more, more preferably 4.0 or more, even more preferably 4.5 or more, even more preferably 5.0 or more, and still more preferably 5.5 or more, in order to suppress discoloration of the liquid oral composition over time.
In addition, from the viewpoint of suppressing bitterness and astringency and adjusting the taste, the mass ratio (c)/((a)+(b)) is preferably 50 or less, more preferably 40 or less, even more preferably 30 or less, and even more preferably 20 or less.

(Component (d))
Component (d) is a copper compound. The liquid oral composition further contains component (d), which can improve the effect of suppressing bad breath. Specific examples of component (d) include water-soluble copper salts.
Specifically, the water-soluble copper salt refers to a water-soluble copper salt among inorganic copper salts and organic copper salts. The water-soluble copper salt may be either anhydrous or hydrated. The water-soluble copper salt may be any salt that is used as a raw material for pharmaceuticals, foods, and cosmetics.
Examples of the water-soluble copper salt include one or more selected from the group consisting of copper gluconate, copper sulfate, copper citrate, copper chlorophyll, and sodium copper chlorophyllin. From the viewpoint of further improving the blending effect of the water-soluble copper salt, such as the effect of suppressing bad breath, the water-soluble copper salt preferably includes at least one of copper gluconate and copper sulfate, and more preferably copper gluconate.
As the water-soluble copper salt, for example, a commercially available product can be used.

The mass ratio (c)/((a) + (b) + (d)) of the content of component (c) to the total content of components (a), (b) and (d) is preferably 2.6 or more, more preferably 3.0 or more, and even more preferably 4.0 or more, in order to suppress discoloration of the liquid oral composition over time.
In addition, from the viewpoint of suppressing bitterness and astringency and adjusting the taste, the mass ratio (c)/((a)+(b)+(d)) is preferably 50 or less, more preferably 40 or less, even more preferably 30 or less, and even more preferably 20 or less.

(water)
Liquid oral compositions specifically contain water.
The water content in the liquid oral composition can be, for example, the remainder after excluding components other than water in the liquid oral composition.
In addition, the water content in the liquid oral composition is preferably 50% by mass or more, more preferably 60% by mass or more, and even more preferably 70% by mass or more, and for example, 99.98% by mass or less, preferably 99.88% by mass or less, more preferably 99.5% by mass or less, and even more preferably 99% by mass or less, based on the entire liquid oral composition.

(ethanol)
The liquid oral composition may further contain ethanol.
The ethanol content in the liquid oral composition is preferably 0.1 mass% or more, more preferably 1 mass% or more, and even more preferably 2 mass% or more, in order to provide a moderately refreshing and pleasant feel when used.
In addition, from the viewpoint of suppressing strong irritation to the oral cavity, the content of ethanol in the liquid oral composition is preferably 30% by mass or less, more preferably 20% by mass or less, even more preferably 15% by mass or less, even more preferably 10% by mass or less, even more preferably 7.5% by mass or less, and even more preferably 5% by mass or less. From the same viewpoint, it is also preferable that the liquid oral composition does not contain ethanol, that is, the content of ethanol is 0% by mass, or the liquid oral composition contains ethanol and the content of ethanol is 5% by mass or less.

An example of a blood circulation promoter is sodium chloride.

An example of a plaque-decomposing enzyme is dextranase.

Humectants may be any of those commercially available as pharmaceutical, food, and cosmetic ingredients, such as polyhydric alcohols, and more specifically, one or more selected from the group consisting of sorbitol, glycerin, concentrated glycerin, ethylene glycol, propylene glycol, 1,3-butylene glycol, propanediol (1,3-propanediol), polyethylene glycol, polypropylene glycol, sodium hyaluronate, and hydrolyzed collagen.

An example of a base is sodium bicarbonate.

An example of a cleaning agent is sodium polyphosphate.

An example of an adsorbent is β-cyclodextrin.

(Production method)
In this embodiment, the liquid oral composition includes, for example, a step of blending components (a), (b) and other components as appropriate.
Here, in order to obtain a liquid oral composition having a color difference ΔE ^* in the above-mentioned range, it is important to appropriately select the components and the blending ratios contained in the liquid oral composition. It is also preferable to appropriately manufacture the liquid oral composition.
For example, it is important to appropriately select and combine the amounts of components (a) and (b) contained in the liquid oral composition to design the composition. It is also preferable to further incorporate component (c) into the liquid oral composition, and it is also preferable to further incorporate components (c) and (d).
In addition, in the manufacturing process of the liquid oral composition, it is preferable to heat a liquid containing components (a) and optionally (d) and water to, for example, about 80°C to obtain liquid 1, and separately heat and dissolve a liquid containing components (b) and optionally (c) at, for example, about 80°C to obtain liquid 2, mix liquids 1 and 2, add water appropriately and mix further to obtain the liquid oral composition.

The liquid oral composition obtained in this embodiment contains components (a) and (b) and has a color difference ΔE ^* within a specific range, so that discoloration over time is suitably suppressed.
In addition, in this embodiment, the method for inhibiting discoloration of a liquid oral composition includes setting the color difference ΔE ^* of the liquid oral composition containing the above components (a) and (b) to 0.0 or more and 2.5 or less.
In this embodiment, the method for inhibiting discoloration of an oral composition may include blending peppermint oil into an oral composition containing at least one of components (a) and (d).

The above describes embodiments of the present invention, but these are merely examples of the present invention, and various configurations other than those described above can also be adopted.

For example, the present invention includes the following aspects.
[A1] The following components (a) to (c):
(a) at least one selected from the group consisting of tranexamic acid and salts thereof;
(b) a fragrance; and (c) a surfactant having an HLB value of 13.0 or more and 20.0 or less,
A liquid oral composition, in which the mass ratio (c)/((a)+(b)) of the content of component (c) to the total content of components (a) and (b) is 3.5 or more.
[A2] Component (d): A liquid oral composition described in [A1] further containing a copper compound.
[A3] A liquid oral composition described in [A1] or [A2], wherein when the liquid oral composition contains ethanol, the ethanol content in the liquid oral composition is 30 mass% or less.
[A4] A liquid oral composition described in any one of [A1] to [A3], wherein the liquid oral composition does not contain ethanol, or the liquid oral composition contains ethanol and the ethanol content in the liquid oral composition is 5% by mass or less.
[A5] A liquid oral composition described in any one of [A1] to [A4], wherein component (b) contains one or more selected from the group consisting of lavender oil, peppermint oil and bergamot oil.
[A6] A liquid oral composition described in any one of [A1] to [A5], wherein component (c) includes one or more selected from the group consisting of polyoxyethylene hydrogenated castor oil, polyoxyethylene cetyl ether, polyoxyethylene behenyl ether and polyethylene glycol fatty acid esters.
[A7] A method for suppressing discoloration of a liquid oral composition, comprising blending a liquid oral composition containing (a) at least one selected from the group consisting of tranexamic acid and its salts, and (b) a fragrance, with component (c): a surfactant having an HLB value of 13.0 or more and 20.0 or less, so that the mass ratio (c)/((a) + (b)) of the content of component (c) to the total content of components (a) and (b) is 3.5 or more.

[B1] (a) at least one selected from the group consisting of tranexamic acid and salts thereof, and (b) a fragrance;
Including,
A liquid oral composition having a color difference ΔE ^* measured by the following method and obtained by the following formula (I) of 0.0 or more and 2.5 or less.
(method)
The liquid oral composition is stored at 25°C and 60°C for 4 weeks, and the chromaticity coordinates of each sample are measured under the following conditions using a spectrophotometer in accordance with JIS Z 8722. Based on the measured values, chromaticity coordinates defined by the CIE 1976 L ^* a ^* b ^* color system are obtained, and the color difference ΔE ^* is calculated.
Measurement method type: Spectrophotometric color measurement method Color matching function type: X, Y, Z values Illuminant type for color measurement: D65 light source/viewing angle 10°
Geometric conditions of illumination and reception: transmission (0°:0°)
Wavelength: Measurement wavelength 380nm to 780nm, Measurement interval: 5nm
ΔE ^* = {(L ^* 2 - L ^* 1) ² + (a ^* 2 - a ^* 1) ² + (b ^* 2 - b ^* 1) ² } ^1/2 (I)
(In the above formula (I), (L ^* 1, a ^* 1, b ^* 1) and (L ^* 2, a ^* 2, b ^* 2) are chromaticity coordinates defined in the CIE1976 ^L* a ^* b ^* color system of the sample after storage at 25°C for 4 weeks and at 60°C for 4 weeks, respectively.)
[B2] A liquid oral composition described in [B1], wherein Δb ^* measured by the above method and obtained by the following formula (II) is 0 or more and 3.0 or less.
Δb ^* = b ^* 2 - b ^* 1 (II)
[B3] Further containing ethanol,
A liquid oral composition described in [B1] or [B2], wherein the content of ethanol in the liquid oral composition is 15 mass% or less relative to the entire liquid oral composition.
[B4] A liquid oral composition described in any one of [B1] to [B3], wherein component (b) is peppermint oil.
[B5] Component (c): A liquid oral composition described in any one of [B1] to [B4], further containing a surfactant having an HLB value of 13.0 or more and 20.0 or less.
[B6] Component (d): A liquid oral composition described in any one of [B1] to [B5], further containing a copper compound.

The present embodiment will be specifically explained below with examples and comparative examples, but the present embodiment is not limited to these examples.

(Test Example 1)
(Examples A1 to A4, Comparative Example A1)
The components shown in Table 1 were mixed to prepare the mouthwash of each example, and the mouthwash was evaluated according to the method described below. Details of the components shown in each table are shown below.
(d) Copper gluconate: manufactured by Fuso Chemical Co., Ltd. (a) Tranexamic acid: manufactured by Kyowa Pharma Chemical Co., Ltd. Polyoxyethylene (40) hydrogenated castor oil, NIKKOL HCO-40, manufactured by Nippon Surfactant Industry Co., Ltd., HLB 12.5
(c) Polyoxyethylene (60) hydrogenated castor oil, NIKKOL HCO-60, manufactured by Nippon Surfactant Industry Co., Ltd., HLB 14
(c) Polyoxyethylene (100) hydrogenated castor oil, NIKKOL HCO-100, manufactured by Nippon Surfactant Industry Co., Ltd., HLB 16.5
(c) Polyoxyethylene cetyl ether BC-23, manufactured by Nippon Surfactant Industry Co., Ltd., HLB 18
Ethanol: Fujifilm Wako Pure Chemical Industries, Ltd. Glycerin: Kosakai Pharmaceutical Co., Ltd. Sodium saccharin: Junsei Chemical Co., Ltd. (b) Bergamot oil: Fujifilm Wako Pure Chemical Industries, Ltd. (b) Lavender oil: Nacalai Tesque, Inc. (b) Peppermint oil: Kosakai Pharmaceutical Co., Ltd.

(Method of preparing mouthwash)
Sodium saccharin, glycerin and water were mixed in the amounts shown in Table 1 and dissolved by stirring in beaker A. Tranexamic acid and, if necessary, copper gluconate were added to beaker A and further dissolved.
Ethanol, fragrance and surfactant were placed in a separate beaker B and dissolved by heating in a water bath at 80°C.
Beaker A was also heated to 80° C., and then placed in beaker B and stirred. Beaker B was removed from the hot water bath and further stirred with a stirrer. Water was added to a final volume of 100 g, and further stirred to obtain the mouthwash of each example.

(Viscosity Measurement)
The viscosity of the mouthwash obtained in each example was measured using a Brookfield rotational viscometer (Brookfield DV3T rotational viscometer, manufactured by Brookfield) at 23°C (room temperature), rotor LV-1, rotation speed 200 rpm, and measurement time: 1 minute. The measurement results are shown in Table 1.

(Evaluation Method)
As an indicator of the discoloration of the mouthwash obtained in each example over time, the change in color after the accelerated test was evaluated using the following method.

(Visual Evaluation)
The mouthwash obtained in each example was stored for one month at 25° C. and 60° C. The degree of discoloration of the sample stored at 60° C. compared to the sample stored at 25° C. was visually evaluated according to the following criteria. The evaluation results are shown in Table 1.
++: Severe discoloration +: Discoloration (yellowing)
±: Discoloration is present but within the acceptable range (discoloration can be confirmed visually)
-: No discoloration (not visible to the naked eye)

(Evaluation using a colorimeter)
Each sample after storage used for visual evaluation was measured under the following conditions using a color difference meter, ΔE ^* (ab) was calculated based on the following formula, and evaluation was performed based on the following criteria. The evaluation results are shown in Table 1.
(Measurement method and conditions)
(Measurement of color difference ΔE ^* )
The mouthwash obtained in each example was dispensed in 50 mL portions of the formulation into 50 mL glass vials to obtain samples 1 and 2. Sample 1 was stored at 25° C. and 60% RH for 4 weeks, and sample 2 was stored in a thermostatic chamber at 60° C. and normal humidity for 4 weeks.
After storage, each specimen was returned to room temperature (25°C) and placed in a measurement cell (No. 1488 5 x 36 x 55 mm) of a spectrophotometer (SE-7700, manufactured by Nippon Denshoku Industries Co., Ltd.), and the chromaticity coordinates (L ^* 1, a ^* 1, b ^* 1) of specimen 1 and the chromaticity coordinates (L ^* 2, a ^* 2, b ^* 2) of specimen 2 were obtained under the following conditions. Each specimen was measured once.
Measurement method type: Spectrophotometric color measurement method Color matching function type: X, Y, Z values Illuminant type for color measurement: D65 light source/viewing angle 10°
Geometric conditions of irradiation and reception: Geometric condition e, transmission (0°:0°)
Wavelength: Measurement wavelength 380nm to 780nm, Measurement interval: 5nm
Based on the obtained chromaticity coordinates, the color difference ΔE ^* of each mouthwash example was calculated using the following formula (I).
ΔE ^* (ab) = {(L ^* 2 - L ^* 1) ² + (a ^* 2 - a ^* 1) ² + (b ^* 2 - b ^* 1) ² } ^1/2 (I)

(evaluation)
For the samples not containing copper compounds (Examples A1 and A2), the following A was judged to be acceptable. For the samples containing copper compounds (Examples A3, A4 and Comparative Example A1), the following A and B were judged to be acceptable, taking into consideration the coloring derived from the copper compounds.
A: ΔE ^* (ab) = 0 or more and 0.5 or less B: ΔE ^* (ab) = 0.5 or more and 2.5 or less C: ΔE ^* (ab) = more than 2.5

As can be seen from Table 1, in each example, discoloration of the mouthwash after the accelerated test was effectively suppressed.

(Test Example 2)
(Examples B1 to B3, Comparative Example B1)
The components shown in Table 2 were mixed to prepare the mouthwash of each example, and the mouthwash was evaluated by the method described below. Details of the components shown in each table are shown below.
(d) Copper gluconate: manufactured by Fuso Chemical Co., Ltd. (a) Tranexamic acid: manufactured by Kyowa Pharma Chemical Co., Ltd. (c) Polyoxyethylene (60) hydrogenated castor oil, NIKKOL HCO-60, manufactured by Nippon Surfactant Industry Co., Ltd., HLB 14
(c) Polyoxyethylene (100) hydrogenated castor oil, NIKKOL HCO-100, manufactured by Nippon Surfactant Industry Co., Ltd., HLB 16.5
Ethanol: Fujifilm Wako Pure Chemical Industries, Ltd. Glycerin: Kosaka Pharmaceutical Co., Ltd. Sodium saccharin: Junsei Chemical Co., Ltd. (b) Peppermint oil: Kosaka Pharmaceutical Co., Ltd.

(Method of preparing mouthwash)
Sodium saccharin, glycerin and water were mixed in the amounts shown in Table 2 and dissolved by stirring in beaker A. Tranexamic acid and, if necessary, copper gluconate were added to beaker A and further dissolved.
Ethanol, fragrance and surfactant were placed in a separate beaker B and dissolved by heating in a water bath at 80°C.
Beaker A was also heated to 80° C., and then placed in beaker B and stirred. Beaker B was removed from the hot water bath and further stirred with a stirrer. Water was added to a final volume of 100 g, and further stirred to obtain the mouthwash of each example.

(Measurement of color difference ΔE ^* )
The mouthwash obtained in each example was dispensed in 50 mL portions of the formulation into 50 mL glass vials to obtain samples 1 and 2. Sample 1 was stored at 25° C. and 60% RH for 4 weeks, and sample 2 was stored in a thermostatic chamber at 60° C. and normal humidity for 4 weeks.
After storage, each specimen was returned to room temperature (25°C) and placed in a measurement cell (No. 1488 5 x 36 x 55 mm) of a spectrophotometer (SE-7700, manufactured by Nippon Denshoku Industries Co., Ltd.), and the chromaticity coordinates (L ^* 1, a ^* 1, b ^* 1) of specimen 1 and the chromaticity coordinates (L ^* 2, a ^* 2, b ^* 2) of specimen 2 were obtained under the following conditions. Each specimen was measured once.
Measurement method type: Spectrophotometric color measurement method Color matching function type: X, Y, Z values Illuminant type for color measurement: D65 light source/viewing angle 10°
Geometric conditions of irradiation and reception: Geometric condition e, transmission (0°:0°)
Wavelength: Measurement wavelength 380nm to 780nm, Measurement interval: 5nm
Based on the obtained chromaticity coordinates, the color differences ΔE ^* and Δb ^* of each example of mouthwash were calculated using the following formulas (I) and (II), respectively.
ΔE ^* = {(L ^* 2 - L ^* 1) ² + (a ^* 2 - a ^* 1) ² + (b ^* 2 - b ^* 1) ² } ^1/2 (I)
Δb ^* = b ^* 2 - b ^* 1 (II)

(Viscosity Measurement)
The viscosity of the mouthwash obtained in each example was measured using a Brookfield rotational viscometer (Brookfield DV3T rotational viscometer, manufactured by Brookfield) at 25°C (room temperature), rotor LV-1, rotation speed 200 rpm, and measurement time: 1 minute. The measurement results are shown in Table 2.

(Evaluation Method)
The discoloration over time of the mouthwash obtained in each example was evaluated using the following method.

(Visual Evaluation)
The mouthwash obtained in each example was stored for 10 months at room temperature (set at 23°C, temperature and humidity as the situation dictated). The degree of discoloration of the samples after storage compared to that immediately after production was visually evaluated according to the following criteria. The evaluation results are shown in Table 2.
++: Severe discoloration +: Discoloration (yellowing)
±: Discoloration is present but within the acceptable range (discoloration can be confirmed visually)
-: No discoloration (not visible to the naked eye)

As can be seen from Table 2, discoloration of the mouthwash over time was effectively suppressed in each example.

This application claims priority based on Japanese Patent Application Nos. 2023-024143 and 2023-024144, filed on February 20, 2023, the disclosures of which are incorporated herein in their entirety.

Claims

The following components (a) and (b):
(a) at least one selected from the group consisting of tranexamic acid and salts thereof;
(b) A liquid oral composition containing a fragrance and satisfying at least one of the following conditions 1 and 2.
(Condition 1)
The following component (c):
(c) a surfactant having an HLB value of 13.0 or more and 20.0 or less,
The mass ratio (c)/((a)+(b)) of the content of the component (c) to the total content of the components (a) and (b) is 3.5 or more (Condition 2).
The color difference ΔE * measured by the following method and obtained by the following formula (I) is 0.0 or more and 2.5 or less (method)
The liquid oral composition is stored at 25°C and 60°C for 4 weeks, and the chromaticity coordinates of each sample are measured under the following conditions using a spectrophotometer in accordance with JIS Z 8722. Based on the measured values, chromaticity coordinates defined by the CIE 1976 L * a * b * color system are obtained, and the color difference ΔE * is calculated.
Measurement method type: Spectrophotometric color measurement method Color matching function type: X, Y, Z values Illuminant type for color measurement: D65 light source/viewing angle 10°
Geometric conditions of illumination and reception: transmission (0°:0°)
Wavelength: Measurement wavelength 380nm to 780nm, Measurement interval: 5nm
ΔE * = {(L * 2 - L * 1) 2 + (a * 2 - a * 1) 2 + (b * 2 - b * 1) 2 } 1/2 (I)
(In the above formula (I), (L * 1, a * 1, b * 1) and (L * 2, a * 2, b * 2) are chromaticity coordinates defined in the CIE1976 L* a * b * color system of the sample after storage at 25°C for 4 weeks and at 60°C for 4 weeks, respectively.)
The liquid oral composition according to claim 1, which satisfies condition 1.
Component (d): The liquid oral composition according to claim 1 or 2, further comprising a copper compound.
The liquid oral composition according to any one of claims 1 to 3, wherein when the liquid oral composition contains ethanol, the content of ethanol in the liquid oral composition is 30 mass% or less.
The liquid oral composition according to any one of claims 1 to 4, wherein the liquid oral composition does not contain ethanol, or the liquid oral composition contains ethanol and the content of ethanol in the liquid oral composition is 5 mass% or less.
The liquid oral composition according to any one of claims 1 to 5, wherein the component (b) contains one or more selected from the group consisting of lavender oil, peppermint oil and bergamot oil.
The liquid oral composition according to any one of claims 1 to 6, wherein the component (c) comprises one or more selected from the group consisting of polyoxyethylene hydrogenated castor oil, polyoxyethylene cetyl ether, polyoxyethylene behenyl ether, and polyethylene glycol fatty acid ester.
The liquid oral composition according to claim 1 or 2, which satisfies condition 2.
A liquid oral composition as described in claim 8, wherein the Δb * measured by the above method and obtained by the following formula (II) is 0 or more and 3.0 or less.
Δb * = b * 2 - b * 1 (II)
Further comprising ethanol,
A liquid oral composition as described in claim 8 or 9, wherein the content of the ethanol in the liquid oral composition is 15 mass% or less relative to the entire liquid oral composition.
The liquid oral composition according to any one of claims 8 to 10, wherein component (b) is peppermint oil.
Component (c): A liquid oral composition according to any one of claims 8 to 11, further comprising a surfactant having an HLB value of 13.0 or more and 20.0 or less.
Component (d): A liquid oral composition according to any one of claims 8 to 12, further comprising a copper compound.
A method for inhibiting discoloration of a liquid oral composition, comprising blending a liquid oral composition containing (a) at least one selected from the group consisting of tranexamic acid and its salts, and (b) a fragrance, with component (c): a surfactant having an HLB value of 13.0 or more and 20.0 or less, so that the mass ratio (c)/((a)+(b)) of the content of component (c) to the total content of components (a) and (b) is 3.5 or more.