JP7635508B2 - Oral Composition - Google Patents

Description

The present invention relates to an oral composition that provides immediate and effective suppression of dentin hypersensitivity.

Dental hypersensitivity is a condition in which exposed dentin is subjected to external thermal, chemical, or physical stimuli, resulting in a temporary, extremely unpleasant pain. To alleviate this symptom, a large number of potassium salts, such as potassium nitrate, which act as nerve desensitizing ingredients that act on exposed nerves, are used, and aluminum salts, such as aluminum lactate, are also used as dentinal tubule sealing ingredients that act using a different approach by blocking the dentinal tubules, and are incorporated into oral compositions.
However, potassium salts such as potassium nitrate have a relatively immediate effect of suppressing dentin hypersensitivity, but the effect is not sufficient and does not last long, and aluminum salts such as aluminum lactate do not have an immediate effect of suppressing dentin hypersensitivity, so their effects are limited. Moreover, when these are mixed into an oral composition, they are easily affected by other ingredients, and the more the amount of potassium salt is increased, the more it affects the basic property of foaming, making it difficult to spread the oral composition throughout the oral cavity, making it difficult to fully suppress dentin hypersensitivity. Therefore, it has been an issue to improve the dentin hypersensitivity suppression effect of potassium salts and the like in oral compositions, and to make it more immediate and effective.

Patent Document 1 (JP Patent No. 5790455) proposes that when a combination system of a specific water-soluble polymer is added to a dentifrice composition containing potassium nitrate or aluminum lactate and sodium lauryl sulfate, foaming is ensured and the dentin hypersensitivity suppression effect is excellent, but the dentin hypersensitivity suppression effect is evaluated after four weeks of use, and is not immediate. Patent Document 2 (JP Patent No. 5924002) proposes that a high rate of dentin hypersensitivity suppression effect can be achieved by controlling the concentration ratio of potassium ions and sodium ions and further adding an amphoteric surfactant and a specific polymer substance, and Patent Document 3 (JP Patent Publication 2017-141178) proposes that foaming performance and dentin hypersensitivity suppression effect can be ensured by adding α-olefin sulfonic acid and sucralose to a dentifrice composition containing potassium nitrate or aluminum lactate.

Patent No. 5790455 Patent No. 5924002 JP 2017-141178 A International Publication No. 2019/107335 International Publication No. 2019/107340 International Publication No. 2019/107338

The present invention has been made in consideration of the above circumstances, and aims to provide an oral composition that provides an immediate and effective anti-dentin hypersensitivity effect.

The inventors conducted extensive research to achieve the above object, and discovered that when a polyacrylate having a weight-average molecular weight of a specific value or less is combined with a potassium salt or aluminum salt having a dentin hypersensitivity suppressing effect in an oral composition, the immediate effect of the dentin hypersensitivity suppressing effect is improved, and a remarkable high dentin hypersensitivity suppressing effect can be immediately and effectively obtained immediately after use. That is, in the present invention, it was discovered that an oral composition containing (A) a polyacrylate having a weight-average molecular weight of 1,000 to 20,000 and (B) one or more selected from potassium nitrate, potassium acetate, potassium chloride, aluminum lactate, and aluminum chloride provides an immediate and effective excellent dentin hypersensitivity suppressing effect and also has a good taste, which led to the invention.

In the present invention, in the oral cavity composition, (A) polyacrylate with a specific molecular weight specifically interacts with (B) component, and the complex between the two is preferentially formed, improving the retention of (B) component in the oral cavity, which is one of the factors that can significantly improve the immediate effect of the hypersensitivity suppression of (B) component. Potassium salt has a nerve dulling effect, and aluminum salt has a dentinal tubule blocking effect, and each exerts a hypersensitivity suppression effect by a different approach, but even though they have such different action mechanisms, in the present invention, the hypersensitivity suppression effect of (B) component is improved by (A) component, and a high hypersensitivity suppression effect can be exerted immediately, and the effect can be sustained from immediately after use.
When the (B) component, especially the potassium salt containing potassium ions, is combined with sodium lauryl sulfate, an anionic surfactant that is widely used in oral compositions to ensure foaming, the strong binding of these components leads to a decrease in the concentration of free potassium ions, resulting in a decrease in the nerve dulling effect, and furthermore, the poorly soluble potassium lauryl sulfate precipitates, resulting in a decrease in the amount of foaming. However, in the present invention, by combining the (A) and (B) components and further combining and blending the (C) component, the above-mentioned problems do not occur, and sufficient foaming with an appropriate amount of foaming is ensured, and the above-mentioned excellent dentin hypersensitivity suppression effect can be exhibited.
As will be apparent from the comparative examples described later, when component (A) is not blended, the dentin hypersensitivity suppression effect (immediate effect) is low, and even when a polyacrylate salt with an inappropriate molecular weight is added, the dentin hypersensitivity suppression effect is poor (Comparative Examples 1 to 9), and the effect of the present invention cannot be obtained.
In Patent Documents 1 to 3, sodium polyacrylate is blended as a water-soluble polymer, a sodium source, and a binder in a dentifrice composition having a dentin hypersensitivity suppressing effect, but there is no mention of its molecular weight. A cross-linked polyacrylic acid or its salt having a weight-average molecular weight of 100,000 or more, usually about 300,000, is generally used as a binder in oral compositions.
In addition, Patent Documents 4 to 6 (WO 2019/107335, WO 2019/107340, WO 2019/107338) are directed to the inhibition of oral biofilm formation and the improvement of irritation by polyacrylic acid with a weight-average molecular weight of 20,000 or less in an oral composition, and do not focus on the inhibition of hypersensitivity. In contrast, the present invention is directed to the improvement of the hypersensitivity inhibiting effect of component (B) by component (A), particularly its immediate effect, and the combined use of components (A) and (B) provides a particularly remarkable effect that cannot be achieved when a polyacrylic acid salt with a weight-average molecular weight of more than 20,000 is used instead of component (A).

Accordingly, the present invention provides the following oral compositions.
[1]
(A) a polyacrylate having a weight average molecular weight of 1,000 or more and 20,000 or less;
(B) an oral composition characterized by containing one or more selected from potassium nitrate, potassium acetate, potassium chloride, aluminum lactate, and aluminum chloride.
[2]
The oral composition according to claim 1, wherein component (B) is selected from potassium nitrate and aluminum lactate.
[3]
The oral composition according to [1] or [2], wherein the content of the (A) component is 0.005 to 2.5 mass % and the content of the (B) component is 1 to 10 mass %.
[4]
The oral composition according to any one of [1] to [3], wherein the mass ratio of (A)/(B) is 0.001 to 0.5.
[5]
The oral composition according to any one of [1] to [4], further comprising (C) an alkyl sulfate.
[6]
The oral composition according to claim 5, wherein the alkyl sulfate (C) is one or more selected from sodium lauryl sulfate and sodium myristyl sulfate.
[7]
The oral composition according to claim 5 or 6, wherein the content of component (C) is 0.1 to 2 mass%.
[8]
The oral composition according to any one of [5] to [7], wherein the mass ratio of (B)/(C) is 1 to 50.
[9]
The oral composition according to any one of [1] to [8], which is a dentifrice composition.
[10]
The oral composition according to any one of [1] to [9], which is used to suppress dentin hypersensitivity.

According to the present invention, it is possible to provide an oral composition that provides an immediate and effective and excellent effect of suppressing dentin hypersensitivity. The oral composition of the present invention has an excellent effect of suppressing dentin hypersensitivity, can ensure good and appropriate foaming, has a good taste, and is effective as a dentin hypersensitivity suppressant that prevents or suppresses dentin hypersensitivity.

The present invention will be described in further detail below. The oral composition of the present invention contains (A) a polyacrylate salt having a weight-average molecular weight of 1,000 to 20,000, and (B) one or more selected from potassium nitrate, potassium acetate, potassium chloride, aluminum lactate, and aluminum chloride, and preferably contains (C) an alkyl sulfate.

(A) Polyacrylate having a weight-average molecular weight of 1,000 to 20,000 acts to enhance the hypersensitivity suppressing effect of component (B), particularly its immediate effect. It also contributes to ensuring foaming. Component (A) reduces unpleasant tastes such as metallic taste derived from component (B), and further masks the irritation caused by component (C) to reduce the unpleasant taste associated with the irritation, ensuring a pleasant taste when used.

The polyacrylate of component (A) has a weight-average molecular weight (Mw) of 1,000 to 20,000, particularly 6,000 to 10,000, and particularly 6,000 to 9,000, which is preferable in terms of improving the hypersensitivity suppression effect of component (B), enhancing its immediate effect, and improving the feel when used. If the weight-average molecular weight of the polyacrylate exceeds 20,000, the effect of improving hypersensitivity suppression is inferior.
The weight average molecular weight was measured by gel permeation chromatography (GPC) according to the method and measurement conditions described in Japanese Patent No. 5740859. The details are shown below (the same applies hereinafter).
Measurement method of weight average molecular weight:
The weight average molecular weight is a value measured using gel permeation chromatography/multi-angle laser light scattering detector (GPC-MALLS) under the following conditions.
Mobile phase: 0.3M _NaClO4
NaN3 aqueous solution Column: TSKgelα-M x 2 Precolumn: TSKguardcolumn α
Standard material: polyethylene glycol

The polyacrylate of component (A) is preferably a linear polyacrylate from the viewpoint of improving the hypersensitivity suppressing effect, particularly the immediate effect.
As the salt, a monovalent salt is preferable, an alkali metal salt or an ammonium salt is more preferable, an alkali metal salt is still more preferable, such as a sodium salt or a potassium salt, and a sodium salt is particularly preferable.
As such polyacrylic acid salts, commercially available products sold by Polysciences Corporation and Toagosei Co., Ltd. can be used.
Specific commercially available products that can be used include sodium polyacrylate (Mw: 1,000); linear, manufactured by Polysciences Co., Ltd.; sodium polyacrylate (Mw: 6,000); linear, manufactured by Toagosei Co., Ltd., Jurymer AC-10NP, Jurymer AC-10NPD, and Aron T-50; sodium polyacrylate (Mw: 8,000); linear, manufactured by Polysciences Co., Ltd.; sodium polyacrylate (Mw: 9,000); linear, manufactured by Polysciences Co., Ltd.; sodium polyacrylate (Mw: 20,000); linear, manufactured by Toagosei Co., Ltd., Aron A-20UN, and the like.

The amount of component (A) is preferably 0.005 to 2.5% (mass %, the same applies below) of the entire composition, more preferably 0.01 to 2%, and even more preferably 0.01 to 1%. If it is 0.005% or more, the immediate effect of the hypersensitivity suppression effect can be sufficiently improved to make it excellent. It can also suppress the unpleasant taste caused by component (B). If too much is added, the immediate effect of the hypersensitivity suppression effect tends to decrease, but if it is 2.5% or less, a sufficient hypersensitivity suppression effect is ensured. It can also maintain good foaming.

Component (B) is one or more selected from potassium nitrate, potassium acetate, potassium chloride, aluminum lactate, and aluminum chloride, which are desensitizing agents and have the effect of suppressing dentin hypersensitivity.
The potassium salts potassium nitrate, potassium acetate and potassium chloride have a denervating effect on the dentinal tubules, while the aluminum salts aluminum lactate and aluminum chloride have a dentinal tubule sealing effect.
The above potassium salts and/or aluminum salts can be used as component (B), and among these, potassium nitrate and/or aluminum lactate are particularly preferred from the standpoint of their effect of suppressing hypersensitivity.

The blending amount of component (B) is preferably 1 to 10% of the total composition, more preferably 2 to 8%. When the blending amount is 1% or more, the hypersensitivity suppression effect is sufficiently excellent, and when it is 10% or less, sufficient foaming is ensured.
The blend amount of component (B), particularly the potassium salt, can be 5% or more (particularly 5 to 8%), and even 6% or more of the total composition in order to ensure the effect of suppressing dentin hypersensitivity and also to ensure foaming.

The ratio (A)/(B) of the amount of component (A) to the amount of component (B) is preferably 0.001 to 0.5 by mass, more preferably 0.002 to 0.4, even more preferably 0.005 to 0.3, and particularly preferably 0.01 to 0.2. When the mass ratio (A)/(B) is within the above range, the effect of suppressing hypersensitivity is more excellent, and the unpleasant taste is suppressed and the taste is good.

In order to ensure foaming, it is preferable to further incorporate (C) an alkyl sulfate into the oral cavity composition of the present invention.
(C) The alkyl sulfate is preferably sodium lauryl sulfate or sodium myristyl sulfate, and particularly preferably sodium lauryl sulfate.

The amount of component (C) in the composition is preferably 0.1-2% of the total composition in terms of foaming and dentin hypersensitivity suppression effect, more preferably 0.1-1.8%, even more preferably 0.6-1.5%, and may be 1.1% or more. If the amount is 0.1% or more, a sufficient amount of foaming can be ensured. If too much is added, it may affect the dentin hypersensitivity suppression effect, but if the amount is 2% or less, the dentin hypersensitivity suppression effect is sufficiently excellent.

The ratio (B)/(C) of the amount of component (B) to the amount of component (C) is preferably 1 to 50 by mass, more preferably 1 to 20, even more preferably 1 to 10, and particularly preferably 1 to 6. When the mass ratio (B)/(C) is within the above range, better foaming can be achieved, a sufficient amount of foaming can be secured, and the hypersensitivity suppression effect can be improved. In addition, unpleasant taste is suppressed and the feeling of use is good.

The oral cavity composition of the present invention is particularly suitable as a dentifrice composition such as toothpaste, and is prepared by a conventional method. In addition to the above-mentioned components, other known components can be added as necessary within a range that does not impair the effects of the present invention. For example, in toothpaste, abrasives, humectants, binders, surfactants, and, if necessary, sweeteners, colorants, preservatives, flavors, active ingredients, etc. can be added. The amounts of the components added may be normal amounts within a range that does not impair the effects of the present invention.
The oral cavity composition of the present invention may contain, as other optional components, components that are usually used depending on the dosage form, as necessary.

Examples of abrasives include silica-based abrasives such as anhydrous silicic acid, precipitated silica, aluminosilicate, and zirconosilicate, calcium phosphate-based compounds such as dibasic calcium phosphate dihydrate or anhydrate, calcium carbonate, and synthetic resin-based abrasives. The amount of abrasive used is usually 2 to 50%, and particularly 10 to 40%.

Humectants include sugar alcohols such as sorbitol and xylitol, and polyhydric alcohols such as glycerin and propylene glycol. The amount of humectant is usually 5 to 50%, and particularly 20 to 45%.

The binder may be an organic or inorganic binder. Specific examples include organic binders such as cellulose derivatives such as sodium carboxymethylcellulose, methylcellulose, and hydroxymethylcellulose, alginic acid derivatives, gums such as xanthan gum, carrageenan, polyvinyl alcohol, and sodium polyacrylate, and inorganic binders such as gelling (thickening) silica and gelling (thickening) aluminum silica. The amount of binder is usually 0.1 to 10%, and particularly 0.1 to 5%.

In addition to the component (C), other anionic surfactants, nonionic surfactants, cationic surfactants, and amphoteric surfactants may be blended.
Optional anionic surfactants include acyl sarcosinates, acyltaurine salts, and acyl amino acid salts.
Examples of the nonionic surfactant include sugar fatty acid esters such as sucrose fatty acid esters, sugar alcohol fatty acid esters, sorbitan fatty acid esters, glycerin fatty acid esters, polyglycerin fatty acid esters, polyoxyethylene sorbitan fatty acid esters, polyoxyethylene hydrogenated castor oil and other polyoxyethylene fatty acid esters, polyoxyethylene higher alcohol ethers, and fatty acid alkanolamides.
Examples of the cationic surfactant include quaternary ammonium salts such as alkyl ammonium salts and alkyl benzyl ammonium salts.
Examples of the amphoteric surfactant include betaine type surfactants such as alkyl betaines and fatty acid amidopropyl betaines, and imidazolinium betaine type surfactants such as alkyl imidazolinium betaines and 2-alkyl-N-carboxymethyl-N-hydroxyethyl imidazolinium betaines.
The amount of the surfactant to be added is usually 0.1 to 10%, particularly 0.5 to 5%.

Colorants include Blue No. 1, Yellow No. 4, titanium dioxide, and the like.
Sweeteners include sodium saccharin and the like.
Examples of the preservative include paraoxybenzoic acid esters such as methylparaben (methyl paraoxybenzoate), benzoic acid, and salts thereof.

Fragrances include peppermint oil, spearmint oil, anise oil, eucalyptus oil, wintergreen oil, cassia oil, clove oil, thyme oil, sage oil, lemon oil, orange oil, peppermint oil, cardamom oil, coriander oil, mandarin oil, lime oil, lavender oil, rosemary oil, laurel oil, chamomile oil, caraway oil, marjoram oil, bay oil, lemongrass oil, origanum oil, pine needle oil, neroli oil, rose oil, jasmine oil, grapefruit oil, sweet ginger oil, Natural fragrances such as yuzu oil, iris concrete, absolute peppermint, absolute rose, orange flower, and processed fragrances (front distillation, back distillation, liquid-liquid extraction, essences, powdered fragrances, etc.) of these natural fragrances, as well as menthol, carvone, anethole, cineole, methyl salicylate, cinnamic aldehyde, eugenol, 3-l-menthoxypropane-1,2-diol, thymol, linalool, linalyl acetate, limonene, It is possible to use a combination of known flavor materials used in oral compositions, such as single flavors such as menthone, menthyl acetate, N-substituted-paramenthan-3-carboxamide, pinene, octylaldehyde, citral, pulegone, carbyl acetate, anisaldehyde, ethyl acetate, ethyl butyrate, allyl cyclohexane propionate, methyl anthranilate, ethyl methylphenyl glycidate, vanillin, undecalactone, hexanal, butanol, isoamyl alcohol, hexenol, dimethyl sulfide, cyclotene, furfural, trimethylpyrazine, ethyl lactate, and ethyl thioacetate, as well as blended flavors such as strawberry flavor, apple flavor, banana flavor, pineapple flavor, grape flavor, mango flavor, butter flavor, milk flavor, fruit mix flavor, and tropical fruit flavor, and the like, and the flavors are not limited to those described in the examples.
The amount of the fragrance to be blended is not particularly limited, but the above-mentioned fragrance materials are preferably used in an amount of 0.000001 to 1% in the composition, and fragrances using the above-mentioned fragrance materials are preferably used in an amount of 0.1 to 2% in the composition.

Optional active ingredients include nonionic bactericides such as isopropylmethylphenol, cationic bactericides such as cetylpyridinium chloride, anti-inflammatory agents such as tranexamic acid and allantoin, enzymes such as dextranase, fluorine-containing compounds such as sodium fluoride and sodium monofluorophosphate, water-soluble phosphate compounds, sodium chloride, ascorbic acid, tocopherol acetate, plant extracts, anti-tartar agents, and anti-plaque agents. The active ingredients can be blended in an effective amount within a range that does not interfere with the effects of the present invention.

The present invention will be specifically explained below with examples and comparative examples, but the present invention is not limited to the following examples. In the following examples, % indicates mass % unless otherwise specified.

[Examples and Comparative Examples]
Dentifrice compositions having the compositions shown in Tables 1 to 5 were prepared by conventional methods and filled into laminated tube containers, which were used as test dentifrice compositions. The test dentifrice compositions were evaluated for their hypersensitivity suppressing effect by the following method. The dentifrice compositions having the compositions shown in Table 1 were also evaluated for their pleasant taste by the following method. The dentifrice compositions having the compositions shown in Tables 2 to 5 were also evaluated for their foaming during tooth brushing by the following method. These results are also shown in each table.
The dentifrice compositions shown in Tables 2 to 4 all had a pleasant taste, with a score of 2.5 or higher when evaluated by the method described below.
Examples 13 and 15 are reference examples.

(1) Method for evaluating the effect of suppressing tooth hypersensitivity The evaluation was carried out by a sensory test using 10 panelists whose teeth feel sensitive when they hold cold water in their mouths.
The test dentifrice composition was squeezed out, 1 cm of which was applied onto the fingertip, and rubbed directly onto the sensitive teeth. The teeth were then brushed for 3 minutes in the usual manner, and the degree of tooth staining when cold water was then placed in the mouth immediately thereafter was judged according to the rating scale shown below.
<Evaluation criteria>
5 points: no tooth sensitivity at all when cold water is held in the mouth after tooth brushing 4 points: no tooth sensitivity when cold water is held in the mouth after tooth brushing 3 points: almost no tooth sensitivity when cold water is held in the mouth after tooth brushing, no problem 2 points: tooth sensitivity when cold water is held in the mouth after tooth brushing 1 point: tooth sensitivity when cold water is held in the mouth after tooth brushing The average score of 10 people was calculated and evaluated. It was judged that the average score of 10 people is less than 3.0 points indicates low immediate effect of dentin hypersensitivity suppression effect, 3.0 points or more but less than 4.0 points indicates excellent immediate effect of dentin hypersensitivity suppression effect, and 4.0 points or more indicates even more excellent immediate effect of dentin hypersensitivity suppression effect.

(2) Method for evaluating foaming during tooth brushing Evaluation was carried out by a sensory test using 10 expert panelists as subjects.
The test dentifrice compositions were extruded and placed on a toothbrush to a thickness of about 1.5 cm, and then used in the usual manner for brushing teeth for about one week (twice a day). The foaming in the oral cavity during tooth brushing was evaluated according to the rating scale shown below.
<Evaluation criteria>
4 points: sufficient amount of foaming 3 points: moderate amount of foaming 2 points: low amount of foaming 1 point: almost no foaming The average score of 10 people was calculated and evaluated. An average score of less than 2.5 points by the 10 people was judged to be insufficient in foaming, 2.5 to 3.0 points was judged to be good in foaming, and 3.0 points or more was judged to be even better in foaming.

(3) Evaluation Method for Taste (Non-offensiveness) Evaluation was carried out by a sensory test using 10 expert panelists as subjects.
The test dentifrice compositions were extruded and placed on a toothbrush to a depth of about 1.5 cm, and then brushed in the same manner as would be normally used to brush teeth. The lack of unpleasant taste felt during brushing was evaluated according to the rating scale shown below.
<Evaluation criteria>
4 points: no unpleasant taste at all 3 points: almost no unpleasant taste 2 points: some unpleasant taste 1 point: unpleasant taste The average score of the 10 people was calculated and evaluated. An average score of the 10 people of less than 2.5 points was judged to be poor in taste (lack of unpleasant taste), 2.5 to 3.0 points was judged to be good in taste (lack of unpleasant taste), and 3.0 points or more was judged to be even better in taste (lack of unpleasant taste).

Details of the raw materials used are shown below.
Component (A):
Sodium polyacrylate (Mw: 1,000)
Linear, Polysciences sodium polyacrylate (Mw: 6,000)
Linear, manufactured by Toagosei Co., Ltd., Jurimer AC-10NP
Sodium polyacrylate (Mw: 9,000)
Linear, Polysciences sodium polyacrylate (Mw: 20,000)
Linear, manufactured by Toagosei Co., Ltd., Aron A-20UN
Sodium polyacrylate (Mw: 300,000, comparison product)
Crosslinked type, manufactured by Polysciences Corporation (B) Component:
Potassium nitrate; manufactured by Otsuka Chemical Co., Ltd. Potassium acetate; manufactured by Yoneyama Chemical Industry Co., Ltd. Potassium chloride; manufactured by Otsuka Chemical Co., Ltd. Aluminum lactate; manufactured by Musashino Chemical Laboratory Co., Ltd. Aluminum chloride; manufactured by Junsei Chemical Co., Ltd. (C) Component:
Sodium lauryl sulfate: Texapon OC-P, manufactured by BASF

Claims (8)

(A) a polyacrylate having a weight average molecular weight of 6,000 or more and 10,000 or less;
and (B) one or more components selected from potassium nitrate, potassium acetate, potassium chloride, aluminum lactate, and aluminum chloride, wherein the content of component (A) is 0.005 to 2.5% by mass, the content of component (B) is 1 to 10% by mass, and the mass ratio of (A)/(B) is 0.001 to 0.5. The oral composition according to claim 1, wherein component (B) is selected from potassium nitrate and aluminum lactate. The oral composition according to claim 1 or 2, further comprising (C) an alkyl sulfate. The oral composition according to claim 3, wherein (C) the alkyl sulfate is at least one selected from sodium lauryl sulfate and sodium myristyl sulfate. The oral composition according to claim 3 or 4, wherein the content of component (C) is 0.1 to 2 mass%. The oral composition according to any one of claims 3 to 5, wherein the mass ratio of (B)/(C) is 1 to 50. The oral composition according to any one of claims 1 to 6, which is a dentifrice composition. The oral composition according to any one of claims 1 to 7, which is used to suppress dentin hypersensitivity.