Gel composition capable of improving stability of tooth whitening product and preparation method of gel composition

Abstract

The invention discloses a gel composition capable of improving the stability of a tooth whitening product. The gel composition comprises the following components in percentage by mass: 60-70% of a hydrogen peroxide solution, 0-5% of an inorganic thickening agent, 0-6% of a cross-linked polyacrylamide gel, 0-0.2% of essence, 0-15% of a gel aid and the balance of water. Stirring and dissolving hydrogen peroxide, glycerol and water to obtain a mixed solution; adding essence and a cross-linked polyacrylamide gel into the mixed solution, and stirring for 10 minutes at a high stirring speed of 1000-2000 rpm (revolutions per minute); and then adding the inorganic thickening agent, and stirring for 15 minutes at a high stirring speed of 2000-3000 rpm to obtain a jelly. The cross-linked polyacrylamide gel is added into the hydrogen peroxide solution, and a proper amount of glycerol or propylene glycol and the inorganic thickening agent are matched, so that the stability of the hydrogen peroxide is remarkably enhanced, the tooth whitening active ingredient hydrogen peroxide is difficult to oxidize and degrade in the storage process, and the gel form is stable.

Description

Technical Field

[0001] This invention relates to the field of teeth whitening compositions, and more particularly to a gel composition that increases the stability of teeth whitening products and a method for preparing the same. Background Technology

[0002] Teeth whitening methods mainly include chemical bleaching with medications, cover-up whitening, and professional teeth cleaning and air polishing to restore the natural color of teeth. With the increasing development of cosmetic dentistry, chemical bleaching methods containing peroxides are becoming more and more popular. This method uses the redox chemical reaction of peroxides to break down the large organic staining molecules on the tooth surface into smaller molecules, thus lightening the color and fading the pigments deposited on the surface and deep layers of the teeth, achieving teeth whitening. The most commonly used effective chemical components for teeth whitening are hydrogen peroxide or urea peroxide. Urea peroxide is an adduct formed by hydrogen bonds between hydrogen peroxide and urea, but its core effective component is still hydrogen peroxide.

[0003] Hydrogen peroxide is a reactive strong oxidizing agent that easily decomposes into water and oxygen. Teeth whitening products containing hydrogen peroxide are typically formulated into a gel form for easy application and retention on the tooth surface. To impart this gel form, a gelling agent, also known as a thickener, is used. The thickening mechanism generally involves hydrophilic groups forming hydrogen bonds with hydroxyl groups in water, complexing water molecules, reducing their activity, and restricting their free flow. This increases the viscosity of the system, forming a gel. Common gelling agents include acrylic polymers, poloxamer series (polyoxyethylene-polyoxypropylene ether block copolymers), cellulose ethers, polyvinylpyrrolidone series, and natural thickeners.

[0004] Acrylic polymer gelling agents are polymers of acrylic acid and its derivatives. The structural formula of acrylic acid is CH2=CH-COOH. Both the α- and β-hydrogen groups can be substituted, and its carboxyl group can be used to derive ester groups (including diesters and polyesters), amides, acyl chlorides, acid anhydrides, etc. Common acrylic polymers are carbomer series products.

[0005] Poloxamer series (polyoxyethylene polyoxypropylene ether block copolymer) gelling agents are a class of high molecular weight nonionic surfactants, which are PEO-PPO-PEO nonionic triblock copolymers composed of polyoxyethylene (PEO) and polyoxypropylene (PPO).

[0006] Cellulose ether gelling agents: such as methylcellulose, carboxymethylcellulose, ethylcellulose, hydroxypropyl methylcellulose, cyanoethylcellulose, benzyl cyanoethylcellulose, and phenylcellulose, etc.

[0007] Polyvinylpyrrolidone (PVP) series gelling agents: PVP is an N-vinylamide nonionic polymeric thickener, including homopolymers, copolymers and crosslinked polymers with relative molecular masses ranging from several thousand to over one million. Common products include PVP-K30, PVP-K60 and PVP-K90. Natural gelling agents: derived from natural plants, animals or microorganisms, such as guar gum, carrageenan, gum arabic, xanthan gum, gelatin, etc. They have a high content of natural impurities, which is detrimental to the stability of hydrogen peroxide.

[0008] All of the above gels share a common drawback: due to the influence of hydrogen peroxide, an active ingredient in teeth whitening products, they are easily oxidized and degraded during storage, causing the gel system to gradually decrease in consistency until it becomes thin and liquefied. Summary of the Invention

[0009] Based on this, the purpose of this invention is to provide a gel composition that increases the stability of teeth whitening products. By adding a cross-linked polyacrylamide gelling agent to a hydrogen peroxide solution and then combining it with an appropriate amount of glycerol or propylene glycol, the stability of hydrogen peroxide is significantly enhanced, so that the active ingredient of teeth whitening, hydrogen peroxide, is not easily oxidized and degraded during storage, and the gel form is stable.

[0010] To achieve the above objectives, the present invention provides the following technical solution: a gel composition that increases the stability of teeth whitening products, comprising hydrogen peroxide solution, a gelling agent, a cross-linked polyacrylamide gelling agent, and an inorganic thickener.

[0011] Furthermore, a gel composition for increasing the stability of teeth whitening products comprises 60-70% by weight of hydrogen peroxide solution, 0-5% of inorganic thickener, 0-6% of cross-linked polyacrylamide gelling agent, 0-0.2% of fragrance, 0-15% of gelling aid, and the balance being water.

[0012] Furthermore, the gelling agent is either glycerin or propylene glycol.

[0013] Furthermore, the inorganic thickener is EH-5 type fumed silica.

[0014] Furthermore, the cross-linked polyacrylamide gelling agent is a copolymer of hydroxyethyl acrylate and sodium acryloyl dimethyl taurate.

[0015] A method for preparing a gel composition that increases the stability of teeth whitening products is as follows: S1: Dissolve hydrogen peroxide, gelling agent and water by stirring to obtain a mixed solution; S2: Add fragrance and cross-linked polyacrylamide gelling agent to the mixed solution obtained in S1, and stir at a high speed of 1000~2000 rpm for 10 minutes; then add inorganic thickener, and stir at a high speed of 2000~3000 rpm for 15 minutes to obtain a gel. S3: The gel obtained in S2 is subjected to vacuum to remove the air mixed in during stirring, thus obtaining a gel composition that increases the stability of teeth whitening products.

[0016] This invention uses cross-linked polyacrylamide gelling agents, combined with appropriate amounts of hydroxyl-rich gelling agents such as glycerol or propylene glycol, which significantly enhances the stability of the teeth whitening gel and the stability of the teeth whitening active ingredient hydrogen peroxide. The composition is not easily oxidized and degraded during storage, and the gel morphology is stable, thus improving the teeth whitening effect.

[0017] Crosslinked polyacrylamide gelling agents, such as hydroxyethyl acrylate / sodium acryloyldimethyl taurate copolymer, crosslink polyacrylamide groups are involved. In these groups, the nitrogen atom of the amino group is replaced by two hydrogen atoms, one in sodium dimethyl taurate and the other in polyacrylic acid, creating a degree of steric hindrance and exhibiting the characteristics of a hindered amine group. The substituents form a physical barrier through steric repulsion, effectively preventing intermolecular collisions. Simultaneously, the nitrogen atom in this molecular configuration can capture free radicals and chelate free oxygen, thus stabilizing hydrogen peroxide molecules. The gel system formed by crosslinked polyacrylamide gelling agents is not easily oxidized and degraded during storage, exhibiting stable gel morphology.

[0018] The addition of inorganic thickeners (such as Cabot Corporation's EH-5 fumed silica) and hydroxyl-rich gelling agents like glycerin or propylene glycol to the composition creates a synergistic effect with cross-linked polyacrylamide gelling agents, further enhancing the stability of the teeth whitening gel. This increases the susceptibility of the whitening active ingredient, hydrogen peroxide, to oxidative degradation during storage, and also ensures a stable gel morphology. The inorganic thickener has a stable chemical structure and will not be oxidized or degraded; glycerin or propylene glycol enhances the hydrogen bonding system with hydroxyl groups in water, forming a stable gel morphology by complexing water molecules together. Detailed Implementation

[0019] In the following examples, percentages are mass percentages.

[0020] Example 1: A gel composition for increasing the stability of teeth whitening products, comprising 60% by weight of 50% hydrogen peroxide, 1% EH-5 type fumed silica, 4% hydroxyethyl acrylate / sodium acryloyl dimethyl taurate copolymer, 0.1% fragrance, 10% glycerin, and the balance being water.

[0021] A method for preparing a gel composition that increases the stability of teeth whitening products is as follows: S1: Dissolve 50% hydrogen peroxide, glycerol and water by stirring to obtain a mixed solution; S2: Add fragrance and hydroxyethyl acrylate / sodium acryloyl dimethyl taurate copolymer to the mixed solution obtained in S1, and stir at a high speed of 1000~2000 rpm for 10 minutes; then add EH-5 type fumed silica, and stir at a high speed of 2000~3000 rpm for 15 minutes to obtain a gel. S3: The gel obtained in S2 is subjected to vacuum to remove the air mixed in during stirring, thus obtaining a gel composition that increases the stability of teeth whitening products.

[0022] Example 2, a gel composition for increasing the stability of teeth whitening products, comprising 60% by weight of 50% hydrogen peroxide, 1% EH-5 type fumed silica, 4% hydroxyethyl acrylate / sodium acryloyl dimethyl taurate copolymer, 0.1% fragrance, and the balance being water.

[0023] A method for preparing a gel composition that increases the stability of teeth whitening products is as follows: S1: Dissolve 50% hydrogen peroxide in water by stirring to obtain a mixed solution; S2: Add fragrance and hydroxyethyl acrylate / sodium acryloyl dimethyl taurate copolymer to the mixed solution obtained in S1, and stir at a high speed of 1000~2000 rpm for 10 minutes; then add EH-5 type fumed silica, and stir at a high speed of 2000~3000 rpm for 15 minutes to obtain a gel. S3: The gel obtained in S2 is subjected to vacuum to remove the air mixed in during stirring, thus obtaining a gel composition that increases the stability of teeth whitening products.

[0024] Example 3, a gel composition for increasing the stability of teeth whitening products, comprising 60% by weight of 50% hydrogen peroxide, 4% hydroxyethyl acrylate / sodium acryloyl dimethyl taurate copolymer, 0.1% fragrance, and the balance being water.

[0025] A method for preparing a gel composition that increases the stability of teeth whitening products is as follows: S1: Dissolve 50% hydrogen peroxide in water by stirring to obtain a mixed solution; S2: Add fragrance and sodium hydroxyethyl acrylate / acryloyl dimethyl taurate copolymer to the mixed solution obtained in S1, and stir at a high speed of 1000~2000 rpm for 10 minutes; S3: The gel obtained in S2 is subjected to vacuum to remove the air mixed in during stirring, thus obtaining a gel composition that increases the stability of teeth whitening products.

[0026] Comparative Example 1: A gel composition that increases the stability of teeth whitening products, comprising 60% by weight of 50% hydrogen peroxide, 3% of C940 carbomer, 0.1% fragrance, 4% of 30% sodium hydroxide, and the balance being water.

[0027] A method for preparing a gel composition that increases the stability of teeth whitening products involves dissolving hydrogen peroxide and water by stirring; adding carbomer and allowing it to stand overnight to allow the carbomer to swell; adding sodium hydroxide solution dropwise while stirring, then adding fragrance, and stirring at a high speed of 1000~2000 rpm for 20 minutes; removing the air mixed in by stirring through a vacuum to obtain the gel.

[0028] Comparative Example 2: A gel composition that increases the stability of teeth whitening products, comprising 60% by weight of 50% hydrogen peroxide, 30% poloxamer (model P407), 0.1% fragrance, and the balance being water.

[0029] A method for preparing a gel composition that increases the stability of teeth whitening products involves dissolving hydrogen peroxide and water by stirring; adding poloxamer and fragrance, stirring, and then allowing it to stand overnight at -20°C to -10°C; removing it and allowing it to return to room temperature to form a gel state; and removing the air mixed in by stirring through vacuum to obtain the gel.

[0030] Comparative Example 3: A gel composition that increases the stability of teeth whitening products, comprising 60% by weight of 50% hydrogen peroxide and 15% polyvinylpyrrolidone (PVPK90). 0.1% fragrance, the remainder is water.

[0031] A method for preparing a gel composition that increases the stability of teeth whitening products involves dissolving 50% hydrogen peroxide and water by stirring; adding polyvinylpyrrolidone and fragrance; stirring at a high speed of 1000-2000 rpm for 30 minutes; and removing the air mixed in by stirring under vacuum to obtain the gel.

[0032] Stability test: Hydrogen peroxide is a reactive strong oxidizing agent that easily decomposes into water and oxygen. Teeth whitening gel products containing hydrogen peroxide are easily degraded by hydrogen peroxide during storage, causing the viscosity of the gel system to gradually decrease until it becomes thin and liquefied and unusable. At the same time, hydrogen peroxide will continue to decompose, resulting in varying degrees of decrease in its content.

[0033] This experiment involved accelerated aging at 37°C for 4 weeks to test the decrease in viscosity and hydrogen peroxide content of the gel system, thereby examining the stability of the comparative and example samples. A smaller decrease in viscosity and hydrogen peroxide content indicated better stability of the sample group. Viscosity was tested according to the "Third Method: Rotational Viscometer Determination" of Viscosity Determination Method 0633 in the Pharmacopoeia of the People's Republic of China (2020 Edition). The hydrogen peroxide content was determined according to the standard "YY / T 0632-2008 Determination of Peroxide Content in Dental Bleaching Materials".

[0034] Table 1: Changes in viscosity and hydrogen peroxide content after accelerated aging at 37°C for 4 weeks in the examples and comparative examples.

[0035] As shown in Table 1, after accelerated aging at 37°C for 4 weeks, the gel viscosity and hydrogen peroxide content of common gelling agents such as carbomer, poloxamer, and polyvinylpyrrolidone all decreased significantly. However, the decrease in viscosity and hydrogen peroxide content of cross-linked polyacrylamide gelling agents was significantly reduced, indicating a significant improvement in product stability. The gel product prepared by combining cross-linked polyacrylamide gelling agents with silica and glycerin produced a synergistic effect, further enhancing the stability of hydrogen peroxide teeth whitening products. The decrease in hydrogen peroxide content was only 10%, the gel viscosity did not decrease, and the gel morphology remained stable.

Claims

1. A gel composition having increased stability of a tooth whitening product, characterized in that This includes hydrogen peroxide solution, gelling aids, cross-linked polyacrylamide gelling agents, and inorganic thickeners.

2. The gel composition according to claim 1, which increases the stability of teeth whitening products, is characterized in that... It includes 60-70% hydrogen peroxide solution, 0-5% inorganic thickener, 0-6% cross-linked polyacrylamide gelling agent, 0-0.2% fragrance, 0-15% gelling aid, and the balance is water.

3. A gel composition according to claim 1 or 2 that increases the stability of teeth whitening products, characterized in that... The gelling agent is either glycerol or propylene glycol.

4. A gel composition according to claim 1 or 2 that increases the stability of teeth whitening products, characterized in that... The inorganic thickener is EH-5 type fumed silica.

5. A gel composition according to claim 1 or 2 that increases the stability of teeth whitening products, characterized in that... The cross-linked polyacrylamide gelling agent is a copolymer of hydroxyethyl acrylate and sodium acryloyl dimethyl taurate.

6. A method for preparing a gel composition that increases the stability of teeth whitening products, comprising using a teeth whitening composition with good storage stability as described in any one of claims 1-5, characterized in that... The preparation method is as follows: S1: Dissolve hydrogen peroxide, glycerol, and water by stirring to obtain a mixed solution; S2: Add fragrance and cross-linked polyacrylamide gelling agent to the mixed solution obtained in S1, and stir at a high speed of 1000~2000 rpm for 10 minutes; then add inorganic thickener, and stir at a high speed of 2000~3000 rpm for 15 minutes to obtain a gel. S3: The gel obtained in S2 is subjected to vacuum to remove the air mixed in during stirring, thus obtaining a gel composition that increases the stability of teeth whitening products.

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