EP4554686A1

EP4554686A1 - Oral care composition

Info

Publication number: EP4554686A1
Application number: EP23733006.3A
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: 2022-07-13
Filing date: 2023-06-26
Publication date: 2025-05-21
Also published as: WO2024012854A1; CN119604271A

Abstract

An oral care composition is disclosed comprising an uncharged polar amino acid, a charged polar amino acid, a water insoluble and/or slightly soluble calcium source, wherein the amount of calcium source to the total amount of uncharged polar amino acid and charged polar amino acid is present in a weight ratio from 1:10 to 20:1 and wherein the composition comprises less than 0.005% by weight of other amino acids in addition to the uncharged polar amino acid and the charged polar amino acid based on the total weight of the composition.

Description

ORAL CARE COMPOSITION

Field of the Invention

The present invention relates to an oral care composition such as toothpastes, powders, gums, mouthwashes, serum and the like. The present invention particularly relates to an oral care composition comprising certain amino acids and a calcium source. The invention also relates to the use of such compositions for remineralizing and/or preventing or reducing dental caries and/or reducing sensitivity of teeth of an individual.

Background of the Invention

Teeth comprise dentin overlaid with an outer layer of enamel. Teeth are under constant attack from chemical and physical forces, including bacteria-derived acids and mechanical wear, resulting in demineralization and weakening of enamel and the underlying dentin. The enamel is composed hydroxyapatite crystals that create a porous surface. There is a need to stop or at least retard the erosion of enamel to maintain good oral health. Fluoride is normally used in oral care products to combat dental caries. The resulting fluorapatite composition is harder than the original hydroxyapatite composition and more resistant to the acidic attack.

Tooth hypersensitivity is a temporary induced pain sensation that affects up to 20% of the adult population. It is associated with tooth demineralization and the loss of either enamel or cementum to expose underlying dentin. The dentin of the tooth generally contains channels, called tubules, which provide for an osmotic flow between the inner pulp region of the tooth and the outer root surfaces. The cause of tooth hypersensitivity may be related to demineralization giving rise to increased exposure of tubules and permeability of the dentine. The most common causes of demineralization of the enamel or dentine are attrition, abrasion, gingival recession and erosion. When root surfaces are exposed, dentinal tubules are also exposed.

The currently accepted theory for tooth hypersensitivity is the hydrodynamic theory, based on the belief that open exposed dentinal tubules allow fluid flow through the tubules. This flow excites the nerve endings in the dental pulp. Clinical replica of sensitive teeth viewed in a SEM (scanning electron microscopy) reveal varying numbers of open or partially occluded dentinal tubules.

Efforts have been made over the years to treat tooth hypersensitivity. One approach is to reduce the excitability of the nerve in a sensitive tooth by using “nerve-depolarising agents” comprising strontium ions, potassium salts such as potassium nitrate, potassium bicarbonate, potassium chloride and the like. These nerve-depolarising agents function by interfering with neural transduction of the pain stimulus to make the nerve less sensitive.

Another approach is to use “tubule blocking agents” that fully or partially occlude tubules such as polystyrene beads, apatite, polyacrylic acid, mineral hectorite clay and the like. These tubule blocking agents function by physically blocking the exposed ends of the dentinal tubules, thereby reducing dentinal fluid movement and reducing the irritation associated with the shear stress described by the hydrodynamic theory.

US 9717929 B2 (COLGATE-PALMOLIVE COMPANY) discloses an oral care composition for reducing tooth hypersensitivity comprising an effective amount of a basic amino acid in free or salt form; and an effective amount of calcium silicate particles, wherein the calcium silicate particles have an average diameter of less than 5 microns, wherein the particles have a d50 of 2 pm to 5 pm, and a d90 of 5 pm to 10 pm, and a cumulative volume percentage at 3.95 of at least 50%.

There still remains a need to develop an oral care composition which is more effective in remineralizing teeth and/or preventing or reducing dental caries and/or occluding dentinal tubules to reduce tooth sensitivity.

Summary of the Invention

In a first aspect, the present invention is directed to an oral care composition comprising: a) an uncharged polar amino acid; b) a charged polar amino acid; c) a water insoluble and/or slightly soluble calcium source; wherein the amount of calcium source to the total amount of uncharged polar amino acid and charged polar amino acid is present in a weight ratio (c:(a+b)) from 1 :10 to 20:1; and wherein the composition comprises less than 0.005% by weight of other amino acids in addition to the uncharged polar amino acid and the charged polar amino acid based on the total weight of the composition.

In a second aspect, the present invention is directed to a packaged oral care product comprising the oral care composition of the first aspect of this invention. In a third aspect, the present invention is directed to a method for remineralizing and/or preventing or reducing dental caries and/or reducing sensitivity of teeth of an individual comprising the step of applying the composition of any embodiment of the first aspect to at least one surface of the teeth of the individual. The method is preferably for non-therapeutic benefits.

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.

“Soluble” and “insoluble” for the purpose of the present invention means the solubility of a source (e.g., like calcium source) in water at 25°C and under atmospheric pressure. “Soluble” means a source that dissolves in water to give a solution with a concentration of at least 0.1 moles per litre. “Insoluble” means a source that dissolves in water to give a solution with a concentration of less than 0.001 moles per litre. “Slightly soluble”, therefore, is defined to mean a source that dissolves in water to give a solution with a concentration of greater than 0.001 moles per litre and less than 0.1 moles per litre. “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. Preferably, the new calcium phosphate layers on teeth is from 10 nm to 20 microns, more preferably from 75 nm to 10 microns, and most preferably from 150 nm to 5 microns thick including all ranges subsumed therein).

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 20 amino acids in the standard genetic code and the others (e.g., selenocysteine, pyrrolysine, ornithine) are found 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 further 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 includes, for example, serine, tyrosine, threonine, cysteine, asparagine, glutamine or mixtures thereof, preferably serine, tyrosine, cysteine or mixtures thereof. Tyrosine is particularly preferred.

The composition preferably comprises the uncharged polar amino acid from 0.01 to 15% by weight of the composition, more preferably from 0.1 to 10%, even more preferably from 0.5 to 8% and most preferably from 1 to 5%, based on total weight of the composition and including all ranges subsumed therein.

Suitable positively charged polar amino acid comprises lysine, arginine, histidine, ornithine 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. Preferably, the charged polar amino acid suitable for use in the present invention is positively charged polar amino acids which comprise lysine, arginine, histidine, ornithine or mixtures thereof, more preferably lysine.

It is also 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. 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.

Preferably the charged polar amino acid is present in the composition in an amount of from 0.01 to 15% by weight of the composition, more preferably from 0.1 to 10%, even more preferably from 0.5 to 8% and most preferably from 1 to 5%, 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 in the composition 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.

The total amount of uncharged polar amino acid and charged polar amino acid in the composition is preferably from 0.1 to 20% by weight of the composition, more preferably from 1 to 15%, even more preferably from 2 to 10% and most preferably from 3 to 8%, based on total weight of the oral care composition and including all ranges subsumed therein.

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

The oral care composition of the present invention is substantially free of other amino acids in addition to the uncharged polar amino acid and the charged polar amino acid which are included in the composition. “Substantially free of”, as used herein, means less than 0.005%, preferably less than 0.001%, more preferably less than 0.0005%, even more preferably from 0 to 0.0005% 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 water insoluble and/or slightly soluble calcium source suitable for use in this invention is limited only to the extent that the same may be used in the mouth. Illustrative yet non-limiting examples of the types of the water insoluble and/or slightly soluble calcium source that may be used in the invention include, for example, calcium carbonate, hydroxyapatite, tricalcium phosphate, calcium deficient hydroxyapatite (Cag(HPO4)(PO4)sOH), dicalcium phosphate, dicalcium phosphate dehydrate, octacalcium phosphate, tetracalcium phosphate, calcium glycerophosphate, calcium lactate, calcium aluminate, calcium oxalate, calcium oxide, calcium carboxymethyl cellulose, calcium alginate, calcium hydroxide, calcium sulfate, calcium salts of citric acid or mixtures thereof. Preferably the water insoluble and/or slightly soluble calcium source comprises calcium carbonate, hydroxyapatite, tricalcium phosphate or mixtures thereof. Hydroxyapatite is most preferred.

It is also preferred that the water insoluble and/or slightly soluble calcium source comprises or is calcium carbonate. Preferably the calcium carbonate has a D50 particle size of 5 microns or less, more preferably from 0.01 to 3 microns, and most preferably from 0.01 to 1.5 microns. Suitable calcium carbonate is commercially available, for example, from Omya under the trade name OMYACARE HP 900 OG.

Preferably, the water insoluble and/or slightly soluble calcium source is present in an amount of from 0.1 to 60% by weight of the composition, more preferably from 0.5 to 55%, even more preferably from 1 to 50%, and most preferably from 3 to 40%, based on total weight of the composition and including all ranges subsumed therein.

The amount of calcium source to the total amount of uncharged polar amino acid and charged polar amino acid is present in the composition at a weight ratio from 1 :10 to 20:1 , preferably from 1:5 to 15:1 , more preferably from 1 :3 to 13:1 , even more preferably from 1:1 to 10:1, including all ratios 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 0.1 to 30%, preferably from 0.5 to 20%, more preferably from 1 to 15% 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 Cis alkyl sulphates (for example sodium lauryl sulphate), Cs to Cis alkyl sulphosuccinates (for example dioctyl sodium sulphosuccinate), Cs to Cis alkyl sulphoacetates (such as sodium lauryl sulphoacetate), Cs to Cis alkyl sarcosinates (such as sodium lauryl sarcosinate), Cs to Cis 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 such as calcium carbonates, silicas and aluminas. 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. When the abrasive is calcium carbonate, the total amount of the water insoluble and/or slightly soluble calcium source and the calcium carbonate abrasive preferably ranges from 0.1 to 60%, more preferably from 0.5 to 55%, even more preferably from 1 to 50% and most preferably from 3 to 40%.

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.

The oral care composition of this invention can be used in a method for remineralizing and/or preventing or reducing dental caries and/or reducing sensitivity of teeth of an individual. Preferably, the method is non-therapeutic. Additionally or alternatively, the present invention is directed to an oral care composition for use in remineralizing and/or preventing or reducing dental caries and/or reducing sensitivity of teeth of an individual. Additionally or alternatively, the present invention is directed to use of an oral care composition for remineralizing and/or preventing or reducing dental caries and/or reducing sensitivity of teeth of an individual, the use is preferably non-therapeutic. Additionally or alternatively, the present invention is directed to use of an oral care composition in the manufacture of a medicament in remineralizing and/or preventing or reducing dental caries and/or reducing sensitivity of teeth of an individual.

The oral care composition may be in any form common in the art. Preferred forms are dentifrices, toothpastes, 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 mPa.s (centipoise), and preferably, from 60,000 to 170,000 mPa.s (centipoise), and most preferably, from 65,000 to 165,000 mPa.s (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

Compositions were prepared as shown in table 1. All ingredients are expressed by weight percent of the total formulation.

TABLE 1 a. Commercially available microchalk (CaCO3) with a particle size 0.85 microns under the trade name Omyacare® HP 900 - OG from Omya International AG company b. Commercially available hydroxyapatite C73-08 from Budenheim, Co., Germany

Methods

Brushing protocol

To evaluate the blockage efficacy of dentinal tubules, fresh toothpaste slurries were prepared by mixing toothpaste with de-ionised (DI) water or sodium phosphate solution for 40 seconds and used immediately. Human dentine discs were eroded by 6% citric acid for 2 mins, then they were treated with different slurries via brushing following the same protocol. Sixteen human dentine discs were separated into eight groups (n=2). The dentine discs were brushed with the slurry under a tooth brushing machine equipped with toothbrushes. The load of the tooth brushing was 170 g +/-5 g and the automatic brushing operated at a speed of 150 rpm. After brushing for 1 min, the dentine discs were soaked in slurry for 1 min. Then the dentine discs were placed in 50 mL DI water and agitated on a flatbed shaker at 150 rpm for 10 strokes. The discs were then soaked in simulated oral fluid (SOF) for at least 6 hours under the condition of a shaking water bath at 37°C and 60.0 rpm. After that, the dentine discs were brushed with the slurry by machine using the same procedure as in the first step. The brushing was repeated twice for one day, then the dentine discs were kept in SOF overnight (>12 hours) in a shaking water bath at 37°C to mimic oral environment. The dentine samples were characterized by scanning electron microscopy (SEM, Hitachi S-4800, Japan) after 3 days of brushings.

Simulated oral fluid was made by combining the ingredients in table 2:

TABLE 2

Scoring Standard for Tubules Blockage

Regardless of the original shape of the dentine discs, a square (with a size of 4mm x 4mm) is selected and one image is captured under 30x magnification. Within this square, five spots (each with a size of 150 pm x 150 pm, one in the middle, and one in every corner) are selected and observed under 1000x magnification. The blockage of tubules is accessed following the standards described in Table 3. The measurement is carried out for the two dentine discs of each test group. TABLE 3

Results

SEM images of the dentine discs were taken after 3 days of brushings. The images were analyzed and scored. The results are reported in table 4.

TABLE 4

After 3 days of brushings, it can be seen from the results that sample 4 in accordance with the present invention provided better tubule blockage efficacy than sample 3 which comprised only calcium carbonate. Similarly, sample 6 in accordance with the present invention provided better tubule blockage efficacy than sample 5.

It could also be seen from the results that sample 6 in accordance with the present invention provided better tubule blockage efficacy than both sample 7 which comprised only an uncharged polar amino acid - tyrosine, and sample 8 which comprised only a charged polar amino acid - lysine.

Claims

1. An oral care composition comprising: a) an uncharged polar amino acid; b) a charged polar amino acid; c) a water insoluble and/or slightly soluble calcium source; wherein the amount of calcium source to the total amount of uncharged polar amino acid and charged polar amino acid is present in a weight ratio (c:(a+b)) from 1 :10 to 20:1; and wherein the composition comprises less than 0.005% by weight of other amino acids in addition to the uncharged polar amino acid and the charged polar amino acid based on the total weight of the composition.

2. The oral care composition according to claim 1 , wherein the amount of calcium source to the total amount of uncharged polar amino acid and charged polar amino acid is present in a weight ratio from 1 :5 to 15:1 , preferably from 1 :3 to 13:1.

3. The oral care composition according to claim 1 or claim 2, wherein total amount of uncharged polar amino acid and charged polar amino acid in the composition ranges from 0.1 to 20%, preferably from 1 to 15%.

4. The oral care composition according to any of the preceding claims, wherein the uncharged polar amino acid and the charged polar amino acid are present in the composition in a weight ratio from 1:15 to 15:1, preferably from 1:10 to 10:1.

5. The oral care composition according to any of the preceding claims, wherein the uncharged polar amino acid comprises serine, tyrosine, threonine, cysteine, asparagine, glutamine or mixtures thereof, preferably serine, tyrosine, cysteine or mixtures thereof, more preferably tyrosine.

6. The oral care composition 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.

7. The oral care composition according to claim 6, wherein the positively charged polar amino acid comprises lysine, arginine, histidine, ornithine or mixtures thereof, preferably lysine. The oral care composition according to claim 6, wherein the negatively charged polar amino acid comprises aspartic acid, glutamic acid or mixtures thereof, preferably glutamic acid. The oral care composition according to any one of claims 1 to 5, wherein the charged polar amino acid is positively charged polar amino acids comprising lysine, arginine, histidine, ornithine or mixtures thereof, preferably lysine. The oral care composition according to any of the preceding claims, wherein the uncharged polar amino acid is tyrosine and the charged polar amino acid is lysine. The oral care composition according to any of the preceding claims, wherein the water insoluble and/or slightly soluble calcium source comprises calcium carbonate, hydroxyapatite, tricalcium phosphate, calcium deficient hydroxyapatite (Cag(HPO4)(PO4)sOH), dicalcium phosphate, dicalcium phosphate dehydrate, octacalcium phosphate, tetracalcium phosphate, calcium glycerophosphate, calcium lactate, calcium aluminate, calcium oxalate, calcium oxide, calcium carboxymethyl cellulose, calcium alginate, calcium hydroxide, calcium sulfate, calcium salts of citric acid or mixtures thereof, preferably calcium carbonate, hydroxyapatite, tricalcium phosphate or mixtures thereof. The oral care composition according to any of the preceding claims, wherein the water insoluble and/or slightly soluble calcium source is present in an amount of from 0.1 to 60% by weight of the composition, preferably from 0.5 to 55%. The oral care composition according to any of the preceding claims, wherein the composition additionally comprises a phosphate source. The oral care composition according to any of the preceding claims, wherein the composition is an aqueous composition. A method for remineralizing and/or preventing or reducing dental caries and/or reducing sensitivity of teeth of an individual comprising the step of applying the composition according to any of the preceding claims to at least one surface of the teeth of the individual.