EP4387585A1

EP4387585A1 - Method for remineralizing of teeth

Info

Publication number: EP4387585A1
Application number: EP22755212.2A
Authority: EP
Inventors: Weining LIU; Xiaohong Wang
Original assignee: Unilever Global IP Ltd; Unilever IP Holdings BV
Current assignee: Unilever Global IP Ltd; Unilever IP Holdings BV
Priority date: 2021-08-20
Filing date: 2022-07-27
Publication date: 2024-06-26
Also published as: CL2024000404A1; CN117835956A; WO2023020801A1

Abstract

Disclosed is a method for remineralizing teeth of an individual comprising the step of applying an uncharged polar amino acid and a charged polar amino acid in a composition to at least one surface of the teeth of the individual, wherein the uncharged polar amino acid comprises serine, tyrosine, threonine, cysteine, asparagine, glutamine or mixtures thereof.

Description

METHOD FOR REMINERALIZING OF TEETH

Field of the Invention

The present invention relates to tooth remineralization. In particular, the present invention relates to a method for remineralizing teeth of an individual comprising the step of applying amino acids in a composition to at least one surface of the teeth of the individual.

Background of the Invention

The primary component of the enamel and dentin in teeth is calcium phosphate in the form of hydroxyapatite (HAP). Owning to the tightly packed hierarchical microstructure of HAP nanocrystals, nature enamel has extremely high hardness and unique mechanical properties. However, many products we consume have a negative impact on our teeth. Acidic drinks and sweets, for example, can result in tooth erosion by attacking enamel which is the outer coating that protects the teeth.

In the mouth, there is a natural equilibrium between HAP being dissolved from the enamel of teeth which is referred to as demineralization, and hydroxyapatite being formed on or in the teeth from substances occurring naturally in the saliva which is referred to as remineralization. This equilibrium is shifting continuously. As long as the rate of demineralization and the rate of remineralization remain in balance, teeth remain strong and healthy.

Caio(P04)e(OH)2(Solid) + 8H⁺(aq) <-> 10Ca²⁺(aq) + 6HPO4²'(aq) + 2H2O

Exposure of the dental hard tissues to acid causes demineralization, resulting in surface softening and a decrease in mineral density. Imbalance in this process results in the formation of dental caries which occurs when more minerals are lost from teeth than can be replaced.

Efforts have been made over the years to address the problem of dissolution or demineralization of tooth enamel and the resultant formation of dental caries or decay. A variety of products have been developed to counteract enamel demineralization caused by acid erosion. Such products often comprise peroxides, abrasives or both. These types of products are often not desired since they do not contribute to the remineralization of teeth and can cause damage to teeth and gums if overused. US 2013/0017240 A1 discloses oral care compositions comprising an orally acceptable vehicle, metal oxide particles having an average particle size of no greater than a dentin tubule and at least one amino acid capable of chelating the metal oxide. It relates to an oral care composition for enhanced delivery of an antiplaque/anticalculus agent to the oral surfaces in the oral cavity, and which may additionally treat or prevent hypersensitivity of the teeth.

It has been found unexpectedly that a combination of certain amino acids in a composition can be used to remineralize teeth of an individual.

Summary of the Invention

In a first aspect, the present invention is directed to a method for remineralizing teeth of an individual comprising the step of applying an uncharged polar amino acid and a charged polar amino acid in a composition to at least one surface of the teeth of the individual, wherein the uncharged polar amino acid comprises serine, tyrosine, threonine, cysteine, asparagine, glutamine or mixtures thereof. In particular, the present invention is directed to a method for remineralizing teeth of an individual comprising the step of applying an uncharged polar amino acid and a charged polar amino acid in a composition to at least one surface of the teeth of the individual, wherein the composition provides better tooth remineralization benefit to a tooth surface in comparison to a composition that does not comprise the uncharged polar amino acid and the charged polar amino acid, wherein the uncharged polar amino acid comprises serine, tyrosine, threonine, cysteine, asparagine, glutamine or mixtures thereof. The method is preferably for non-therapeutic benefits.

In a second aspect, the present invention is directed to an uncharged polar amino acid and a charged polar amino acid in a composition for use in remineralizing teeth of an individual, wherein the uncharged polar amino acid comprises serine, tyrosine, threonine, cysteine, asparagine, glutamine or mixtures thereof.

In a third aspect, the present invention is directed to use of an uncharged polar amino acid and a charged polar amino acid in a composition for remineralizing teeth of an individual, wherein the uncharged polar amino acid comprises serine, tyrosine, threonine, cysteine, asparagine, glutamine or mixtures thereof. The use is preferably for non-therapeutic benefits.

In a fourth aspect, the present invention to use of an uncharged polar amino acid and a charged polar amino acid in a composition in the manufacture of a medicament in remineralizing teeth of an individual, wherein the uncharged polar amino acid comprises serine, tyrosine, threonine, cysteine, asparagine, glutamine or mixtures thereof.

All other aspects of the present invention will more readily become apparent upon considering the detailed description and examples which follow.

Detailed Description of the Invention

Except in the examples, or where otherwise explicitly indicated, all numbers in this description indicating amounts of material or conditions of reaction, physical properties of materials and/or use may optionally be understood as modified by the word “about”.

All amounts are by weight of the final composition, unless otherwise specified. It should be noted that in specifying any ranges of values, any particular upper value can be associated with any particular lower value.

For the avoidance of doubt, the word “comprising” is intended to mean “including” but not necessarily “consisting of” or “composed of’. In other words, the listed steps or options need not be exhaustive.

The disclosure of the invention as found herein is to be considered to cover all embodiments as found in the claims as being multiply dependent upon each other irrespective of the fact that claims may be found without multiple dependency or redundancy.

Where a feature is disclosed with respect to a particular aspect of the invention (for example a composition of the invention), such disclosure is also to be considered to apply to any other aspect of the invention (for example a method of the invention) mutatis mutandis.

It has now been found that a combination of certain amino acids in a composition can be used to remineralize teeth. “Remineralization” for the purpose of the present invention means in situ (i.e. in the oral cavity) generation of calcium phosphate on teeth to reduce the likelihood of tooth sensitivity, tooth decay, regenerate enamel and/or improve the appearance of teeth by whitening through the generation of such new calcium phosphate.

Amino acids are organic molecules that consist of a basic amino group (-NH2) and an acidic carboxyl group (-COOH) and an organic side chain that is unique to each amino acid. It is known so far that there are 22 amino acids including 20 amino acids in the standard genetic code and the additional two (selenocysteine and pyrrolysine) are found only in a few bacteria. The 20 amino acids include alanine, arginine, asparagine, aspartic acid, cysteine, glutamine, glutamic acid, glycine, histidine, isoleucine, leucine, lysine, methionine, phenylalanine, proline, serine, threonine, tryptophan, tyrosine and valine.

The amino acids can be divided into two groups: nonpolar amino acids and polar amino acids. Polar amino acids have hydrophilic side chains, which can be divided into three groups: uncharged (neutral) polar amino acids, positively charged polar amino acids and negatively charged polar amino acids.

The uncharged polar amino acid suitable for use in this invention comprises serine, tyrosine, threonine, cysteine, asparagine, glutamine or mixtures thereof, preferably serine, tyrosine, cysteine or mixtures thereof. Tyrosine is particularly preferred.

Preferably the uncharged polar amino acid is present in the composition in an amount of from 0.001 to 5% by weight of the composition, more preferably from 0.005 to 3%, most preferably from 0.01 to 1%, based on total weight of the composition and including all ranges subsumed therein.

It is preferred that the charged polar amino acid suitable for use in the present invention is a combination of positively charged polar amino acids and negatively charged polar amino acids. Suitable positively charged polar amino acid comprises lysine, arginine, histidine or mixtures thereof, preferably the positively charged polar amino acid comprises or is lysine. Suitable negatively charged polar amino acids comprises aspartic acid, glutamic acid or mixtures thereof, preferably the negatively charged polar amino acid comprises or is glutamic acid. The combination preferably comprises the positively charged polar amino acid and the negatively charged polar amino acid in a weight ratio from 10:1 to 1 :20, more preferably from 5:1 to 1:10.

It is also preferred that the charged polar amino acid suitable for use in the present invention is positively charged polar amino acids which comprise lysine, arginine, histidine or mixtures thereof, more preferably lysine.

Preferably the charged polar amino acid is present in the composition in an amount of from 0.001 to 5% by weight of the composition, more preferably from 0.005 to 3%, most preferably from 0.01 to 1%, based on total weight of the composition and including all ranges subsumed therein. The weight ratio of the uncharged polar amino acid to the charged polar amino acid is preferably from 1 :15 to 15:1 , more preferably from 1 :10 to 10:1 , and most preferably from 1 :5 to 5:1.

It is especially preferred that the uncharged polar amino acid is tyrosine and the charged polar amino acid is lysine.

The composition of the present invention may comprise other amino acids in addition to the uncharged polar amino acid and the charged polar amino acid. Preferably, the composition is substantially free of other amino acids. “Substantially free of’, as used herein, means less than 0.005%, preferably less than 0.001%, more preferably from 0 to 0.001 % by weight, based on total weight of the composition, including all ranges subsumed therein. Preferably, the composition of the present invention does not comprise other amino acids in addition to the uncharged polar amino acid and the charged polar amino acid which are included in the composition.

The composition may comprise a calcium source. Preferably the calcium source dissolves in water to give a calcium ion concentration of at least 0.001 moles per liter at room temperature and atmospheric pressure. Illustrative yet non-limiting examples of the types of calcium source that may be used in this invention include, for example, calcium hydroxide, calcium oxide, calcium glycerophosphate, calcium lactate, calcium sulfate, calcium salts of citric acid, calcium chloride, calcium nitrate, calcium acetate, calcium gluconate, calcium formate, calcium malate, calcium propionate, calcium butyrate, calcium bicarbonate, monocalcium phosphate anhydrous, dicalcium phosphate anhydrous, tricalcium phosphate, octacalcium phosphate, calcium carboxymethyl cellulose, calcium alginate, mixtures thereof or the like.

Preferably, the calcium source comprises calcium chloride, calcium nitrate, calcium glycerophosphate, calcium lactate, calcium acetate, calcium gluconate, calcium carbonate, calcium silicate or mixtures thereof. More preferably the calcium source comprises calcium chloride, calcium acetate, calcium gluconate, calcium glycerophosphate or mixtures thereof.

The calcium source may be present in the range of from 0.01 to 50%, preferably from 0.1 to 30%, more preferably from 1 to 20% by weight of the composition, based on total weight of the composition and including all ranges subsumed therein. The composition may comprise a phosphate source. Preferably the phosphate source dissolves in water to give a phosphate ion concentration of at least 0.1 moles per liter at room temperature and atmospheric pressure. Illustrative examples of the types of phosphate source suitable for use in this invention include trisodium phosphate, monosodium dihydrogen phosphate, disodium hydrogen phosphate, ammonium phosphate, diammonium hydrogen phosphate, ammonium dihydrogen phosphate, tripotassium phosphate, monopotassium dihydrogen phosphate, dipotassium hydrogen phosphate, mixtures thereof or the like.

The phosphate source may be present in the range of from 0.05 to 50%, preferably from 2 to 40%, more preferably from 5 to 35% by weight of the composition, based on total weight of the composition and including all ranges subsumed therein.

The calcium source and the phosphate source may be present in a weight ratio from 1:10 to 30:1, preferably from 1 :5 to 20:1, more preferably from 1 :3 to 15:1.

Preferably, the composition is an aqueous composition. The water content is at least 1.5% by weight of the composition, preferably at least 5%, more preferably at least 10%. It is preferable that the water content is from 1.5 to 95% by weight of the composition, more preferably from 5 to 90% and most preferably from 10 to 90%, based on total weight of the composition and including all ranges subsumed therein.

Typically, the composition has a pH from 5.5 to 10.5, more preferably from 6.0 to 10, and most preferably from 6.5 to 9.0. The pH of composition may be measured when 5 parts by weight of the composition is uniformly dispersed and/or dissolved in 20 parts by weight pure water at 25°C. In particular, the pH may be measured by manually mixing 5 g composition with 20 mL water for 30 s, then immediately testing the pH with indicator or a pH meter. Or the pH of composition may be measured directly with a pH meter.

The composition of the present invention may also comprise a physiologically acceptable carrier. The carrier preferably comprises at least surfactant, thickener, humectant or a combination thereof.

Preferably the composition comprises a surfactant. Preferably the composition comprises at least 0.01% surfactant by weight of the composition, more preferably at least 0.1% and most preferably from 0.5 to 7%. Suitable surfactants include anionic surfactants, such as the sodium, magnesium, ammonium or ethanolamine salts of Cs to C alkyl sulphates (for example sodium lauryl sulphate), Cs to C alkyl sulphosuccinates (for example dioctyl sodium sulphosuccinate), Cs to C alkyl sulphoacetates (such as sodium lauryl sulphoacetate), Cs to C alkyl sarcosinates (such as sodium lauryl sarcosinate), Cs to C alkyl phosphates (which can optionally comprise up to 10 ethylene oxide and/or propylene oxide units) and sulphated monoglycerides. Other suitable surfactants include nonionic surfactants, such as optionally polyethoxylated fatty acid sorbitan esters, ethoxylated fatty acids, esters of polyethylene glycol, ethoxylates of fatty acid monoglycerides and diglycerides, and ethylene oxide/propylene oxide block polymers. Other suitable surfactants include amphoteric surfactants, such as betaines or sulphobetaines. Mixtures of any of the above described materials may also be used. More preferably the surfactant comprises or is anionic surfactant. The preferred anionic surfactants are sodium lauryl sulphate and/or sodium dodecylbenzene sulfonate. Most preferably the surfactant is sodium lauryl sulphate, sodium coco sulfate, cocam idopropyl betaine, sodium methyl cocoyl taurate or mixtures thereof.

Thickener may also be used in this invention. Illustrative examples of the types of thickeners that may be used in this invention include, sodium carboxymethyl cellulose (SCMC), hydroxyl ethyl cellulose, methyl cellulose, ethyl cellulose, gum tragacanth, gum arabic, gum karaya, sodium alginate, carrageenan, guar, xanthan gum, Irish moss, starch, modified starch, silica based thickeners including silica aerogels, magnesium aluminum silicate (e.g., Veegum), Carbomers (cross-linked acrylates) and mixtures thereof.

Typically, xanthan gum and/or sodium carboxymethyl cellulose and/or a Carbomer is/are preferred. When a Carbomer is employed, those having a weight-average molecular weight of at least 700,000 are desired, and preferably, those having a molecular weight of at least 1 ,200,000, and most preferably, those having a molecular weight of at least about 2,500,000 are desired. Mixtures of Carbomers may also be used herein.

In an especially preferred embodiment, the Carbomer is Synthalen PNC, Synthalen KP or a mixture thereof. It has been described as a high molecular weight and cross-linked polyacrylic acid and identified via CAS number 9063-87-0. These types of materials are available commercially from suppliers like Sigma.

In another especially preferred embodiment, the sodium carboxymethyl cellulose (SCMC) used is SCMC 9H. It has been described as a sodium salt of a cellulose derivative with carboxymethyl groups bound to hydroxy groups of glucopyranose backbone monomers and identified via CAS number 9004-32-4. The same is available from suppliers like Alfa Chem. In another especially preferred embodiment, the thickener is xanthan gum.

Thickener typically makes up from 0.01 to about 10%, more preferably from 0.1 to 9%, and most preferably, from 0.1 to 5% by weight of the composition, based on total weight of the composition and including all ranges subsumed therein.

Suitable humectants are preferably used in the composition of the present invention and they include, for example, glycerin, sorbitol, propylene glycol, dipropylene glycol, diglycerol, triacetin, mineral oil, polyethylene glycol (preferably, PEG-400), alkane diols like butane diol and hexanediol, ethanol, pentylene glycol, or a mixture thereof. Glycerin, polyethylene glycol, sorbitol or mixtures thereof are the preferred humectants.

The humectant may be present in the range of from 10 to 90% by weight of the composition. More preferably, the carrier humectant makes up from 25 to 80%, and most preferably, from 30 to 60% by weight of the composition, based on total weight of the composition and including all ranges subsumed therein.

The composition may comprise a fluoride source. Preferred fluoride source includes sodium fluoride, stannous fluoride, potassium fluoride, sodium monofluorophosphate, sodium fluorosilicate, ammonium fluorosilicate, amine fluoride, ammonium fluoride or mixtures thereof. Preferably, the fluoride source is stannous fluoride, sodium fluoride, sodium monofluorophosphate or mixtures thereof. Sodium monofluorophosphate is particularly preferred. The fluoride source may be present at a level from 0.01 to 10%, more preferably from 0.03 to 5% and most preferably from 0.1 to 2% by weight of the composition, based on total weight of the composition and including all ranges subsumed therein.

The composition may comprise abrasives. Preferred abrasives include silicas, aluminas, calcium carbonates, dicalcium phosphates, calcium pyrophosphates, hydroxyapatites, trimetaphosphates, insoluble hexametaphosphates or mixtures thereof, including agglomerated particulate abrasives. Calcium carbonate and silica are particularly preferred, especially silica. The abrasives may be present in the range of from 0.01 to 60%, more preferably from 0.1 to 30%, and most preferably from 1 to 15% by weight of the composition, based on total weight of the composition and including all ranges subsumed therein.

The composition of the present invention may contain a variety of other ingredients which are common in the art to enhance physical properties and performance in addition to the amino acids that are included in the composition. These ingredients include opacifying agents, colouring agents, anti-microbial agents, anti-inflammatory agents, anti-caries agents, plaque buffers, vitamins, plant extracts, desensitizing agents, anti-calculus agents, biomolecules, flavours, proteinaceous materials, preservatives, pH-adjusting agents, sweetening agents, polymeric compounds, buffers and salts to buffer the pH and ionic strength of the compositions, and mixtures thereof.

Such ingredients typically and collectively make up less than 20% by weight of the composition, and preferably, from 0.0 to 15% by weight, and most preferably, from 0.01 to 12% by weight of the composition, including all ranges subsumed therein.

Preferably, the composition is an oral care composition. Preferred forms are dentifrices, tooth pastes, gels, mouthwashes, medicaments, oral films, serums, chewing gums and lozenges, more preferably a tooth paste or a gel. When the oral care composition is a toothpaste or gel, the same typically has a viscosity from about 30,000 to 180,000 centipoise, and preferably, from 60,000 to 170,000 centipoise, and most preferably, from 65,000 to 165,000 centipoise, taken at room temperature (25°C) with a Brookfield Viscometer, Spindle No.93/94 and at a speed of 5 rpm for 1 minute. Typically the composition will be packaged. In tooth paste or gel form, the composition may be packaged in a conventional plastic laminate, metal tube or a single compartment dispenser. The same may be applied to dental surfaces by any physical means, such as a toothbrush, fingertip or by an applicator directly to the sensitive area. In liquid mouthwash form the composition may be packaged in a bottle, sachet or other convenient container.

The composition can be effective even when used in an individual’s daily oral hygiene routine. For example, the composition may be brushed onto the teeth. The composition may, for example, be contacted with the teeth for a time period of one second to 20 hours. More preferably from 1 s to 10 hours, more preferably still from 10 s to 1 hour and most preferably from 30 s to 5 minutes. The composition may be used daily, for example for use by an individual once, twice or three times per day.

The following examples are provided to facilitate an understanding of the present invention. The examples are not provided to limit the scope of the claims. Examples

Example 1

This example demonstrated the surface microhardness (SMH) change of tooth enamels. All ingredients are expressed by weight percent of the total formulation and as level of active ingredient.

TABLE 1

Methods

The enamel surface microhardness (SMH) was measured by a microhardness tester (Struers Durascan) using a Knoop indenter at 50gf load for 10 seconds. Five indentations were made per test point for each enamel block in different regions to avoid residual stress. To evaluate the microhardness of tooth enamel, well-polished human enamel blocks were divided into eight groups (n=5 per group) with similar baseline values of SMH. The SMH of the human enamel blocks were measured and recorded as SM Hbaseiine. The human enamel blocks were soaked in 1wt% citric acid (pH 3.6) for 10 minutes and then rinsed with water. The SMH of the eroded enamel blocks were measured and recorded as SM Heroded.

60 pL of test sample was added onto surfaces of the eroded enamel blocks and left on the surfaces for 10 minutes. The test sample was then removed and the enamel blocks were soaked in simulated oral fluid (SOF) at 37°C for 6 hours. After that, another 60 pL of test sample was added onto the enamel blocks as in the first step. The enamel blocks were then soaked in SOF overnight (>12 hours) in a shaking water bath at 37°C to mimic oral environment. The whole treatment within one day was called one-day treatment cycle. The treatment was repeated for 7 days and the SMH of the enamel blocks were measured and recorded as SM Htreated- Simulated oral fluid was made by combining the ingredients in Table 2:

TABLE 2

Results

The results are summarized in table 3. The SMH recovery was calculated according to the following equation:

SMH Recovery (%)— (SM Htreated"SM Heroded) X 100/(SM Hbaseline"SM Heroded)

SMH recovery can be used to evaluate the remineralization of tooth enamel. The higher the

SMH recovery, the better remineralization of tooth enamel.

TABLE 3

Sample 1 comprising only water was used as negative control. It can be seen from the results that that human enamel blocks treated with sample 7 or 8 comprising tyrosine and lysine showed better SMH recovery than those treated with other samples, which indicated better tooth remineralization efficacy of sample 7 or 8.

Claims

1 . A method for remineralizing teeth of an individual comprising the step of applying an uncharged polar amino acid and a charged polar amino acid in a composition to at least one surface of the teeth of the individual, wherein the uncharged polar amino acid comprises serine, tyrosine, threonine, cysteine, asparagine, glutamine or mixtures thereof.

2. The method according to claim 1 , wherein the composition provides better tooth remineralization benefit to a tooth surface in comparison to a composition that does not comprise the uncharged polar amino acid and the charged polar amino acid.

3. The method according to claim 1 or claim 2, wherein the uncharged polar amino acid comprises serine, tyrosine, cysteine or mixtures thereof, preferably tyrosine.

4. The method according to any of the preceding claims, wherein the uncharged polar amino acid is present in the composition in an amount of from 0.001 to 5% by weight of the composition, preferably from 0.005 to 3%.

5. The method according to any of the preceding claims, wherein the charged polar amino acid is a combination of positively charged polar amino acids and negatively charged polar amino acids.

6. The method according to claim 5, wherein the positively charged polar amino acid comprises lysine, arginine, histidine or mixtures thereof, preferably lysine.

7. The method according to claim 5, wherein the negatively charged polar amino acid comprises aspartic acid, glutamic acid or mixtures thereof, preferably glutamic acid.

8. The method according to any one of claims 1 to 4, wherein the charged polar amino acid is positively charged polar amino acids comprising lysine, arginine, histidine or mixtures thereof, preferably lysine.

9. The method according to any of the preceding claims, wherein the charged polar amino acid is present in the composition in an amount of from 0.001 to 5% by weight of the composition, preferably from 0.005 to 3%. The method according to any of the preceding claims, wherein the weight ratio of the uncharged polar amino acid to the charged polar amino acid is from 1 : 15 to 15: 1 , preferably from 1 : 10 to 10:1. The method according to any of the preceding claims, wherein the uncharged polar amino acid is tyrosine and the charged polar amino acid is lysine. The method according to any of the preceding claims, wherein the composition is substantially free of other amino acids in addition to the uncharged polar amino acid and the charged polar amino acid. The method according to any of the preceding claims, wherein the composition additionally comprises a calcium source. The method according to any of the preceding claims, wherein the composition additionally comprises a phosphate source. The method according to any of the preceding claims, wherein the composition is an aqueous composition.