Method for suppressing precipitation of insoluble substances in liquid oral compositions, and liquid oral compositions

Abstract

To provide a method for inhibiting deposition of insoluble substance when blending a liquid oral composition with aluminium lactate and glycyrrhizinate, and a liquid oral composition containing aluminium lactate and glycyrrhizinate with the deposition of insoluble substance inhibited.SOLUTION: The present invention discloses a method for inhibiting deposition of insoluble substance in a liquid oral composition. The method includes blending (C) potassium nitrate in the liquid oral composition containing (A) aluminium lactate and (B) glycyrrhizinate.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a method for suppressing precipitation of insoluble substances in a liquid oral composition and a liquid oral composition.

Background Art

[0002] Conventionally, oral compositions such as dentifrices and mouthwashes have been used to keep teeth clean and maintain oral health. Oral compositions contain a variety of components to impart functions according to various uses.

[0003] One of the oral problems is dentin hypersensitivity. Dentin hypersensitivity is a condition in which the enamel of the tooth is lost and the dentin is exposed, and external stimuli such as temperature, chemical, and mechanical stimuli are applied to the dentin, causing pain. This is thought to be because the nerves are stimulated through the dentinal tubules that are continuous from the outermost layer of the dentin to the dental pulp. As a countermeasure against dentin hypersensitivity, methods such as blocking the dentinal tubules using aluminum lactate or numbing the nerves with potassium nitrate have been taken. For example, Patent Document 1 discloses an oral composition containing an active ingredient for narrowing and occluding dentinal tubules that contains aluminum and a carboxylate group in a dissolved state and has a molar ratio of the carboxylate group to 1 mol of the aluminum of 6 or less, and further contains a phosphate compound and has a pH of 5 or more.

[0004] In addition, for the purpose of anti-inflammatory effects in the oral cavity, anti-inflammatory agents such as glycyrrhizinate are incorporated into oral compositions. For example, Patent Document 2 discloses a dentifrice composition containing (A) dipotassium glycyrrhizinate, (B) sodium chloride, and (C) trimethylglycine, wherein the blending amount of the component (B) is 1 to 15% by mass of the whole composition, and the mass ratio [(C) / (A)] of the component (A) and the component (C) is 50 to 500.

Prior Art Documents

Patent Documents

[0005] Patent Document 1 Japanese Unexamined Patent Application Publication No. 07-165550 Patent Document 2 Japanese Unexamined Patent Application Publication No. 2009-107988 Summary of the Invention Problems to be Solved by the Invention

[0006] As a result of the study by the present inventor, it has been found that when both aluminum lactate and glycyrrhizinate are blended in a liquid oral composition such as a mouthwash or a liquid dentifrice, insoluble substances precipitate and settle over time. In a liquid oral composition, the insoluble precipitate is a major problem in terms of the appearance of the product.

[0007] Therefore, an object of the present invention is to provide a method for suppressing the precipitation of insoluble substances when aluminum lactate and glycyrrhizinate are blended in a liquid oral composition, and a liquid oral composition containing aluminum lactate and glycyrrhizinate in which the precipitation of insoluble substances is suppressed. Means for Solving the Problems

[0008] As a result of intensive studies, the present inventor has found that when potassium nitrate is blended in a liquid oral composition containing aluminum lactate and glycyrrhizinate, the precipitation of insoluble substances can be suppressed, and thus the present invention has been completed.

[0009] That is, the present invention is achieved by the following (1) to (4). (1) A method for suppressing the precipitation of insoluble substances in a liquid oral composition, characterized in that (C) potassium nitrate is contained in a liquid oral composition containing (A) aluminum lactate and (B) glycyrrhizinate. (2) The method for suppressing the precipitation of insoluble substances in the liquid oral composition according to (1) above, characterized in that the (C) potassium nitrate is contained in the liquid oral composition in the range of 1 to 15 w / v%. (3) A liquid oral composition characterized by containing (A) aluminum lactate, (B) glycyrrhizinate, and further containing (C) potassium nitrate. (4) The liquid oral composition according to (3) above, characterized in that the light transmittance at a wavelength of 660 nm when left standing at 50 °C for 4 weeks is 95% or more. [Effects of the Invention]

[0010] According to the method of the present invention, precipitation of insoluble substances due to the incorporation of aluminum lactate and glycyrrhizinate in the liquid oral composition can be suppressed. Therefore, generation of insoluble precipitates in the liquid oral composition can be suppressed, and the stability of the product over time can be maintained. [Modes for Carrying Out the Invention]

[0011] Hereinafter, embodiments of the present invention will be described in more detail. In the present invention, the unit "w / v%" of the blending amount means mass / volume percentage (component content (g) in the liquid oral composition (100 mL)).

[0012] [Method for Suppressing Precipitation of Insoluble Substances in Liquid Oral Composition] The method for suppressing precipitation of insoluble substances in the liquid oral composition of the present invention includes adding (C) potassium nitrate to a liquid oral composition containing (A) aluminum lactate and (B) glycyrrhizinate.

[0013] (A) Aluminum lactate seals the dentinal tubules in the dentin of the tooth, which is a pain transmission pathway, and thus has an effect of suppressing dentin hypersensitivity in the oral composition.

[0014] (A) Aluminum lactate is preferably contained in the liquid oral composition in the range of 1 to 10 w / v%. When the content of (A) aluminum lactate is 1 w / v% or more, the effect of occluding dentinal tubules can be obtained, and the stability of aluminum lactate in the composition also decreases. Therefore, it is preferably contained at 10 w / v% or less. The content of (A) aluminum lactate is more preferably 1 to 7 w / v%, still more preferably 1 to 5 w / v%, and particularly preferably 1 to 3 w / v%.

[0015] (B) Glycyrrhizinate has an anti-inflammatory effect in the oral composition. Examples of glycyrrhizinate include potassium salts such as monopotassium glycyrrhizinate and dipotassium glycyrrhizinate; sodium salts such as monosodium glycyrrhizinate and disodium glycyrrhizinate; ammonium salts such as monoammonium glycyrrhizinate and diammonium glycyrrhizinate. Among these, from the viewpoint of the stability of the liquid oral composition, potassium salts and ammonium salts of glycyrrhizic acid are preferred, and dipotassium glycyrrhizinate and monoammonium glycyrrhizinate are more preferred.

[0016] (B) Glycyrrhizinate is preferably contained in the liquid oral composition in the range of 0.001 to 3 w / v% in terms of the amount converted to glycyrrhizic acid. When the content of (B) glycyrrhizinate is 0.001 w / v% or more in terms of the amount converted to glycyrrhizic acid, an effective anti-inflammatory effect can be obtained, and it is preferably contained at 3 w / v% or less in consideration of the fragrance within the range permitted for blending with cosmetics, pharmaceuticals, or external preparations for quasi-drugs. The content of (B) glycyrrhizinate is more preferably 0.001 to 2 w / v% in terms of the amount converted to glycyrrhizic acid, and still more preferably 0.01 to 1 w / v%.

[0017] The content of glycyrrhizic acid can be measured by a conventional method of high performance liquid chromatography using high performance liquid chromatography.

[0018] The liquid oral composition of the present invention preferably contains (D) water in the range of 40 to 99 w / v%. When the content of (D) water is less than 40 w / v%, it becomes difficult to keep the oral composition in a liquid state, and when it is 99 w / v% or less, the active ingredient can be contained in an effective amount. The content of (D) water is more preferably 40 to 90 w / v%, and even more preferably 50 to 80 w / v%.

[0019] Examples of the water include purified water, ionized water, distilled water and the like.

[0020] In the present specification, the term "liquid" refers to a substance having fluidity and a viscosity at 20°C of 20 mPa·s or less, preferably 10 mPa·s or less. Here, the viscosity can be measured using a commercially available rotational viscometer (for example, the R-type viscometer manufactured by Toki Sangyo Co., Ltd.).

[0021] When (A) aluminum lactate and (B) glycyrrhizinate coexist in the liquid oral composition, insoluble substances may precipitate over time and sediments may form. This is presumably because (A) aluminum lactate and (B) glycyrrhizinate react to precipitate aluminum glycyrrhizinate, and aluminum glycyrrhizinate is insoluble in water, so it exists as a sediment in the liquid oral composition. As a result of the study by the present inventor, when (C) potassium nitrate is contained in the liquid oral composition containing (A) aluminum lactate and (B) glycyrrhizinate, although its effect is not clear, it has been found that the precipitation of such insoluble substances is suppressed. (C) Potassium nitrate is used as an active ingredient for suppressing dentin hypersensitivity in the oral composition in the same manner as (A) aluminum lactate, but in the present invention, it is used as a precipitant inhibitor of insoluble substances.

[0022] (C) Potassium nitrate is preferably contained in the liquid oral composition in the range of 1 to 15 w / v%. When (C) potassium nitrate is contained at 1 w / v% or more, the effects of the present invention can be obtained. When the content is 15 w / v% or less, the flavor of the liquid oral composition is not impaired. (C) Potassium nitrate is more preferably contained in the range of 1 to 12 w / v%, and even more preferably 1 to 5 w / v%.

[0023] Also, from the viewpoint of appropriately obtaining the effect of suppressing the precipitation of insoluble substances in the liquid oral composition, (C) potassium nitrate is preferably contained in the range of 0.5 to 5 in terms of mass ratio with respect to (A) aluminum lactate 1. When the content of (C) potassium nitrate is 0.5 times or more with respect to (A) aluminum lactate 1 in terms of mass ratio, the effects of the present invention can be obtained, and no significant difference in the effects is observed even when the content exceeds 5 times. (C) Potassium nitrate is more preferably contained in the range of 1 to 5 in terms of mass ratio with respect to (A) aluminum lactate 1.

[0024] (Liquid oral composition) The liquid oral composition of the present invention contains (A) aluminum lactate and (B) glycyrrhizinate, and further contains (C) potassium nitrate.

[0025] (A) Aluminum lactate is as described above, and the same applies to the preferred content range.

[0026] (B) Glycyrrhizinate is as described above, and the same applies to the preferred glycyrrhizinate and the preferred content range.

[0027] (C) Potassium nitrate is as described above, and the same applies to the preferred content range.

[0028] The liquid oral composition preferably contains (D) water in the range of 40 to 99 w / v%. (D) Water is as described above, and the same applies to the preferred content range.

[0029] The liquid oral composition of the present invention can contain various components applicable in the oral cavity as long as the effects of the present invention are not impaired. For example, solvents, humectants, flavoring agents, bactericides, anti-inflammatory agents, surfactants (solubilizers), pH adjusters, enzymes, ion sources, preservatives (preservatives), fragrances, crude drugs, pigments, etc. can be mentioned.

[0030] Examples of the solvent include lower alcohols such as ethanol in addition to water.

[0031] Examples of the humectant include glycerin, ethylene glycol, propylene glycol, 1,3-butylene glycol, polyethylene glycol, polypropylene glycol, etc.

[0032] Examples of the flavoring agent include sweeteners such as stevioside, xylitol, erythritol, maltitol, sorbitol, sodium saccharin, sucralose, reduced palatinose, aspartame, etc.

[0033] Examples of the bactericide include cationic bactericides such as benzethonium chloride, cetylpyridinium chloride, benzalkonium chloride, chlorhexidine hydrochloride, chlorhexidine gluconate, triclosan, isopropylmethylphenol, hinokitiol, thymol, alkyl diaminethyl glycine hydrochloride solution, etc.

[0034] Examples of the anti-inflammatory agent include tranexamic acid, epsilon-aminocaproic acid, allantoin, allantoin chloroaluminum hydroxide, dihydrocholesterol, glycyrrhetinic acid, etc. in addition to glycyrrhizinate.

[0035] Examples of surfactants include nonionic surfactants, cationic surfactants, anionic surfactants, or amphoteric surfactants. Specifically, examples of nonionic surfactants include glycerin fatty acid esters, sucrose fatty acid esters, sorbitan fatty acid esters, polyoxyethylene fatty acid esters, polyoxyethylene sorbitan fatty acid esters, fatty acid diethanolamides, fatty acid monoglycerides, polyoxyethylene alkyl ethers, polyoxyethylene hydrogenated castor oil, alkyl glucosides, polyoxyethylene polyoxypropylene block copolymers, etc. Examples of cationic surfactants include alkyltrimethylammonium chlorides, dialkyldimethylammonium chlorides, etc. Examples of anionic surfactants include sulfate esters, α-olefin sulfonates, sulfosuccinates, N-acyl amino acid salts, acylated methyl taurine salts, etc. Examples of amphoteric surfactants include betaine acetate type surfactants, imidazoline type surfactants, etc.

[0036] Examples of pH adjusters include, for example, sodium dihydrogen phosphate, disodium hydrogen phosphate, sodium citrate, citric acid, glucono δ-lactone, sodium gluconate, sodium acetate, sodium hydroxide, and hydrates thereof, etc.

[0037] Examples of enzymes include, for example, proteases, dextranases, amylases, mutanases, lysozymes, etc.

[0038] Examples of ion sources include, for example, fluoride ion sources such as sodium fluoride, monofluorophosphate, stannous fluoride, etc., and phosphate ion sources such as calcium phosphate, hydroxyapatite, etc.

[0039] Examples of preservatives include, for example, para-hydroxybenzoic acid esters such as methyl para-hydroxybenzoate, propyl para-hydroxybenzoate, etc., sodium benzoate, phenoxyethanol, etc.

[0040] Examples of the fragrance include natural essential oils such as peppermint oil, spearmint oil, perilla oil, eucalyptus oil, clove oil, thyme oil, and rosemary oil, and fragrance components such as l-menthol, l-carvone, carvacrol, eugenol, anethole, 1,8-cineole, hinokitiol, and thymol.

[0041] Examples of the crude drug include, for example, magnolia bark extract, gardenia extract, and the like.

[0042] Examples of the pigment include, for example, Food Blue No. 1, Food Yellow No. 4, Food Red No. 102, Food Green No. 3, and the like.

[0043] (Production of the liquid oral composition) The liquid oral composition of the present invention can be used in the form of a mouthwash, a liquid dentifrice, an oral coolant, a gargle (mouthwash), or the like. These can be formulated by known means.

[0044] For example, to prepare a mouthwash, (D) water and an alcoholic solvent such as ethanol are used as a solvent, and (A) aluminum lactate, (B) glycyrrhizinate, (C) potassium nitrate, and, if desired, other various components are added and prepared by a conventional method. For example, a mouthwash can be prepared by adding a surfactant and an oily component (such as a fragrance and a preservative) to an alcoholic solvent, adding water thereto for solubilization, and then adding aluminum lactate, glycyrrhizinate, potassium nitrate, and a water-soluble component thereto.

[0045] Note that it is preferable that the alcoholic solvent be contained in a range of 25 w / v% or less based on the total amount of the mouthwash because irritation in the oral cavity can be suppressed. The content of the alcoholic solvent is more preferably 10 w / v% or less.

[0046] (Physical properties of the liquid oral composition) When the liquid oral composition of the present invention is allowed to stand at 50°C for 4 weeks, if there is no precipitation of insoluble substances in the liquid oral composition, the light transmittance at a wavelength of 660 nm is 95% or more, and it can be confirmed that it is stable over time. The light transmittance is more preferably 97% or more, and even more preferably 99% or more.

[0047] Note that the light transmittance can be measured in accordance with the transmitted light measurement method in the turbidity test method of the Japanese Pharmacopoeia (Sixteenth Revision, Second Addendum). Specifically, it is determined by measuring the transmittance of the liquid oral composition at a wavelength of 660 nm by ultraviolet-visible light measurement using a spectrophotometer or a photoelectric altimeter.

[0048] In addition, the liquid oral composition of the present invention preferably has a pH of 5 to 10 because the feeling of use in the oral cavity becomes even better.

[0049] (Method of using the liquid oral composition) As a method of using the liquid oral composition of the present invention, when applying it to the oral cavity as a mouthwash, 5 to 25 mL of the liquid oral composition is put into the mouth and used by rinsing it in the oral cavity for 15 to 60 seconds. Thereby, the liquid oral composition of the present invention can be sufficiently spread in the oral cavity.

Examples

[0050] Hereinafter, the present invention will be further described with reference to Examples and Comparative Examples, but the present invention is not limited to the following examples.

[0051] <Test Example 1> (Examples 1 to 10, Comparative Examples 1 to 3, Reference Examples 1 to 2) 1. Preparation of the liquid oral composition According to the formulation shown in Table 1, each component was mixed with stirring to prepare a liquid oral composition. Since the pH of the composition changes and solubilization becomes impossible depending on the blending amount of aluminum lactate, sodium hydroxide "0.33" was blended with respect to the mass "1" of aluminum lactate so that the pH became almost constant. However, for Example 5, it was solubilized at "0.72" with respect to the mass "3" of aluminum lactate.

[0052] 2. Confirmation of precipitation of insoluble substances 80 g of the liquid oral composition was filled into a transparent plastic bottle (capacity 87 mL) to obtain a test specimen. The test specimen was stored statically at 50 °C for 4 weeks, and after 4 weeks, the appearance was visually confirmed to evaluate the presence or absence of insoluble substances. Those in which no precipitation of insoluble substances was observed were evaluated as "○", and those in which precipitation of insoluble substances was confirmed were evaluated as "×". The results are shown in Table 1.

[0053] 3. Measurement of light transmittance Regarding the liquid oral composition after being stored statically at 50 °C for 4 weeks, which was evaluated in the above "2. Confirmation of precipitation of insoluble substances", in accordance with the transmitted light measurement method in the turbidity test method of the Japanese Pharmacopoeia (16th Revision, Second Supplement), using a spectrophotometer, the light transmittance (%) at a wavelength of 660 nm was measured by ultraviolet-visible light measurement method. The results are shown in Table 1.

[0054]

Table 1

[0055] From the comparison between Reference Examples 1 and 2 and Comparative Examples 1 to 3, it was found that the coexistence of aluminum lactate and glycyrrhizinate caused precipitation of insoluble substances in the liquid oral composition. And from Examples 1 to 10, it was found that when potassium nitrate was contained in the liquid oral composition containing aluminum lactate and glycyrrhizinate, precipitation of insoluble substances could be suppressed. Examples 1 to 10 showed no precipitation of insoluble substances even after being stored statically at 50 °C for 4 weeks, and the light transmittance was also 99% or more in all cases, indicating excellent transparency. Storage at 50 °C for 4 weeks is equivalent to about 12 months when stored at room temperature (15 - 25 °C, according to the Japanese Pharmacopoeia), and it was found that the liquid oral composition of the present invention has excellent long-term storage stability.

[0056] <Test Example 2> (Examples 11 - 12, Comparative Example 4) 1. Preparation of liquid oral composition In Test Example 1, dipotassium glycyrrhizinate was used as the glycyrrhizinate, while in Test Example 2, ammonium glycyrrhizinate was used as the glycyrrhizinate. According to the formulation shown in Table 2, each component was mixed with stirring to prepare a liquid oral composition.

[0057] 2. Confirmation of precipitation of insoluble substances and measurement of light transmittance For the liquid oral compositions of Examples 11 to 12 and Comparative Example 4, in the same manner as in Test Example 1, the presence or absence of precipitation of insoluble substances was confirmed, and the light transmittance was further measured. The results are shown in Table 2.

[0058]

Table 2

[0059] From the results in Table 2, it was found that even when an ammonium glycyrrhizinate salt was used as the glycyrrhizinate, precipitation of insoluble substances could be suppressed by including potassium nitrate in the liquid oral composition containing aluminum lactate and an ammonium glycyrrhizinate salt. Also, it was found that Examples 11 to 12 had a light transmittance of 99% or more and were excellent in transparency.

Claims

1. A method for suppressing precipitation of insoluble substances in a liquid oral composition, characterized in that (C) potassium nitrate is added to a liquid oral composition containing (A) aluminum lactate and (B) glycyrrhizinate in an amount of 0.0047 to 0.014 in terms of glycyrrhizic acid relative to 1 part by mass of the (A) aluminum lactate.

2. The method for suppressing precipitation of insoluble substances in a liquid oral composition according to claim 1, characterized in that the (C) potassium nitrate is contained in the liquid oral composition in a range of 1 to 15 w / v%.

3. A liquid oral composition (excluding the case where a linear aliphatic aldehyde having 8 to 11 carbon atoms and a lactone having 6 to 12 carbon atoms are simultaneously contained), characterized by containing (A) aluminum lactate and (B) glycyrrhizinate, the content of the (B) glycyrrhizinate being 0.0047 to 0.014 in terms of glycyrrhizic acid relative to 1 part by mass of the (A) aluminum lactate, and further containing (C) potassium nitrate.

4. The liquid oral composition according to claim 3, characterized in that the light transmittance at a wavelength of 660 nm is 95% or more when left standing at 50 °C for 4 weeks.

Images