JP2968396B2 - Aqueous oral gel base - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an aqueous gel base for oral cavity.

[0002]

2. Description of the Related Art As a nonionic binder in a water-based oral composition such as a dentifrice, hydroxyethyl cellulose (hereinafter referred to as HEC) or the like is used, but gelation takes a very long time. Moreover, it is difficult to obtain good physical properties suitable for use, such as low thixotropy. On the other hand, Japanese Patent Application Laid-Open No. 60-104008 discloses the use of HEC hydrophobically modified with a hydrocarbon group having 8 to 25 carbon atoms in order to control the physical properties of a gel toothpaste. The thixotropic property of this substance is low, and unless an inorganic thickener is added, appropriate physical properties as an oral gel cannot be obtained. Further, the hydrophobic groups of this substance have a uniform chain length, and use of a combination of hydrophobic groups having different chain lengths is not disclosed. Furthermore, it has not yet been proposed to use a hydrophobically modified substance using hydroxypropylmethylcellulose (hereinafter referred to as HPMC) as a raw material polymer as an oral gel base.

[0003]

SUMMARY OF THE INVENTION In view of such circumstances, the present inventors have developed an aqueous gel for oral use that is rich in thixotropic properties by using a nonionic binder without adding an inorganic thickener. As a result of diligent research for the purpose of obtaining, a hydrophobized HPMC by introducing two types of substituted alkyl groups having different carbon numbers was used as a binder, a specific wetting agent, and water Was found to provide an aqueous gel base for the oral cavity having good physical properties, thereby completing the present invention.

That is, the present invention relates to (1) hydroxypropyl methylcellulose wherein the hydroxyl group is (a) 3
-Alkoxy-2-hydroxypropoxyl group (however, alkoxy has 8 to 12 carbon atoms) and (b) 3-
An alkoxy-2-hydroxypropoxyl group (provided that
The carbon number of the alkoxy is substituted by 14-18),
And the substitution degree (MS) of (a) is 0.0005 to 0.0
3, the substitution degree (MS) of (b) is 0.0005 to 0.0
Hydroxypropyl methylcellulose hydrophobically modified such that the sum of the degrees of substitution (MS) of (a) and (b) is 0.001 to 0.03, (2) glycerin, An aqueous gel base for oral use comprising (3) a wetting agent selected from the group consisting of propylene glycol, polyethylene glycol and mixtures thereof, and (3) water. Here, "MS" means the average number of moles of the substituent bonded per glucose unit.

In the present invention, the hydrophobically modified HP
MC (hereinafter, referred to as HM-HPMC) has a hydroxyl group of HPMC,

[0006]

Embedded image [Wherein, R ₁ represents an alkyl group having 8 to 12 carbon atoms],

[0007]

Embedded image [Wherein, R ₂ represents an alkyl group having 14 to 18 carbon atoms].

In the present invention, the degree of substitution of the methyl group and the hydroxypropyl group of HPMC, which is a raw material of HM-HPMC, is not particularly limited as long as the HPMC is water-soluble. 0.0-3
0.0% by weight, hydroxypropoxyl group is 4.0-1%
Up to 2.0% by weight, any of which can be used. The viscosity of the HPMC is not particularly limited. For example, the viscosity at 20 ° C. in a 2% aqueous solution is 10 to 10%.
Any of up to about 000 cP can be used,
In order to obtain a high viscosity with a smaller amount of addition,
It is desirable to use one of about 000 to 100,000 cP. For example, Shin-Etsu Chemical's Metros 60S
H10,000, 65SH15,000, 90SH10
000 can be used. As a modifying agent for introducing a hydrophobic group, each having 8 to 12 carbon atoms and 14 to 18 carbon atoms
Two alkyl glycidyl ethers having the following alkyl groups are used. HM-HPMC used in the present invention
It is characterized with medium chain (C ₈ ~C ₁₂₎ and a hydrophobic group two having different long chain (C ₁₄ ~C _18). In using a commercially available alkyl glycidyl ether, it may not always be composed of the same number of carbon atoms. For example, C ₁₈
When a hydrophobic group is introduced, stearyl glycidyl ether can be used as a modifier. However, since stearyl glycidyl ether which is commercially available at a low cost contains about 30% of cetyl glycidyl ether, this modifier is actually used. Thus, a mixed substituent of C ₁₈ and C ₁₆ is introduced.
However, in the present invention, such substituents are not considered as two different types of hydrophobic groups.

In the production of HM-HPMC, for example, HPMC is dispersed in a lower alcohol such as isopropyl alcohol or t-butyl alcohol, alkali is added to alkali cellulose, and alkyl glycidyl ether is added thereto. And by heating. After terminating the reaction by neutralization, it is washed and purified with an organic solvent. The thus obtained HM-
HPMC has a solubility in water of at least 0.1% by weight at 25 ° C. In applying the HM-HPMC to an aqueous gel base for oral cavity, its content is usually
0.5 to 5% by weight. If it is lower than 0.5% by weight, sufficient viscosity cannot be obtained, and if it exceeds 5% by weight, the viscosity becomes high,
Unsuitable for use due to showing rubber-like elasticity.

[0010] The wetting agent used in the present invention is selected from the group consisting of glycerin, propylene glycol, polyethylene glycol and mixtures thereof, and is 1 to 80% by weight, preferably 10 to 40% by weight based on the aqueous gel base for oral cavity. It is contained in the ratio of. Usually, the balance is water. The aqueous gel base for oral cavity of the present invention can be produced by a method known per se, and other components (eg, abrasives, surfactants) within the range not impairing the effects of the present invention in the aqueous gel base for oral cavity. And a flavoring agent).

[0011]

EXAMPLES Next, the present invention will be described more specifically with reference to Production Examples, Examples and Comparative Examples, but the present invention is not limited to these Examples. Unless otherwise specified, "%" represents% by weight.

Production Example 1 Production of HM-HPMC In a 5 liter reactor having a twin-screw stirrer, 29% of methoxyl groups, 9.0% of hydroxypropoxyl groups and 2%
% Aqueous solution having a viscosity of 9,000 cP at 20 ° C. and 400 g of isopropyl alcohol
g, NaOH 12 g, and alkyl glycidyl ether were further charged and reacted at 80 ° C. for 5 hours under nitrogen flow.
Then, the reaction slurry was neutralized with acetic acid, cooled, and then mixed with hexane-isopropyl alcohol (1: 1 w / w).
After washing with 200 g three times, drying and grinding, HM-HPM
C was obtained. The content of the 3-alkoxy-2-hydroxypropoxyl group in HM-HPMC was measured by quantifying a gas chromatograph of alkyl iodide formed after decomposing a sample with hydroiodic acid.

Examples 1-3 and Comparative Examples 1-4 After HM-HPMC and glycerin are mixed by stirring for 1 minute according to the above-mentioned formulation, water is added and the mixture is further stirred for 10 minutes. For this gel, the viscosity was measured and the non-Newtonian index was calculated under the following conditions.

Viscosity measurement conditions BH type viscometer, rotor No. 7, 20 ° C., 2 minutes Non-Newtonian index An index calculated by the following formula. The lower the numerical value, the higher the thixotropic property.

[0015]

(Equation 1)

2. Overall Evaluation The physical properties of the HM-HPMC according to the degree of hydrophobic group substitution were comprehensively evaluated according to the following criteria. Table 1 shows the results. …: Apparent viscosity at 20 rpm measurement is 300 poise or more, and non-Newtonian index is 0.35 or less. ×: apparent viscosity of less than 300 poise at 20 rpm measurement,
Or the non-Newtonian index is greater than 0.35.

(Results)

[Table 1]

Table 1 shows differences in physical properties based on substituted hydrophobic groups in HPMC. Comparative Examples 1 and 3 are insoluble in HM-HPMC substituted with a single hydrophobic group. However, as in Examples 1 and 3, Comparative Examples 1 and 3 respectively
It can be seen that HM-HPMC substituted with a mixed hydrophobic group, which is the same total substituent as that of, is solubilized. Further, in Comparative Example 4, it can be seen that HM-HPMC substituted with a C ₆ alkyl hydrophobic group has low thixotropy and is not suitable as a gel for oral cavity. Therefore, the number of carbon atoms in the alkyl glycidyl ether hydrophobic group was at C ₈ or higher. Moreover, since there is a case where it becomes insoluble in a mixed substituent as in Comparative Example 2, C ₈ -C ₁₂ alkyl group substitution degree (M. S.) is 0.0005 to 0.03, C ₁₄ -C ₁₈ alkyl The degree of group substitution (MS) is 0.0005 to 0.005,
And the sum of these alkyl group substitution degrees (MS) is 0.0
The range was limited to 01 to 0.03.

Examples 4-6 and Comparative Examples 5-7 Gel properties were evaluated in the same manner as described above. However,
As the hydrophobic group composition of HM-HPMC, that of Example 1 (Table 1) was used. Table 2 shows the results.

(Results)

[Table 2]

Table 2 shows HM-HP for various wetting agents.
The evaluation of the compatibility of MC (Example 1) is shown. As shown in Examples 4 to 6, HM-HPMC has good compatibility with glycerin, propylene glycol, and polyethylene glycol, and a gel having high thixotropic properties can be obtained. On the other hand, as shown in Comparative Examples 5 to 7, 1,3-butylene glycol, sorbitol and maltitol both have low viscosity and thixotropic properties and have poor compatibility.

[0022]

According to the present invention, an aqueous gel base for oral cavity having extremely excellent viscosity and thixotropic properties and stable over time can be obtained.

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Yuka Ogawa 77-42 Oyamazaki Yata, Oyamazaki-cho, Otonun-gun, Kyoto (72) Inventor Shigeki Mori 1-1-407 Nasara, Takatsuki-shi, Osaka (56) References JP 60-104008 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) A61K 7/00-7/50

Claims (2)

(57) [Claims] (1) In hydroxypropyl methylcellulose, the hydroxyl group is (a) 3-alkoxy-2-
(A) substituted with a hydroxypropoxyl group (provided that the alkoxy has 8 to 12 carbon atoms) and (b) a 3-alkoxy-2-hydroxypropoxyl group (provided that the alkoxy has 14 to 18 carbon atoms); Has a substitution degree (MS) of 0.0005 to 0.0
3, the substitution degree (MS) of (b) is 0.0005 to 0.0
Hydroxypropyl methylcellulose hydrophobically modified such that the sum of the degrees of substitution (MS) of (a) and (b) is 0.001 to 0.03, (2) glycerin, An aqueous gel base for oral use, comprising: a wetting agent selected from the group consisting of propylene glycol, polyethylene glycol and mixtures thereof; and (3) water. 2. The composition according to claim 1, which contains 0.5 to 5% by weight of hydrophobically modified hydroxypropylmethylcellulose.
The aqueous gel base for oral use according to the above.