Oral care composition

Abstract

The present invention relates to oral care compositions having an improved cleaning efficacy. There remains a need to provide an oral care composition that provides a long-lasting freshness effect. It has been surprisingly found that an oral care composition having a combination of natural calcium carbonate and precipitated calcium carbonate in combination where the two are maintained in specific ratio ranges provides enhanced cleaning efficacy while maintaining lower relative abrasivity.

Description

[0001] ORAL CARE COMPOSITION

[0002] Field of the Invention

[0003] The present invention relates to oral care composition. More particularly, the present invention is concerned with oral care composition having improved cleaning efficacy.

[0004] Background of the Invention

[0005] Abrasives for use in oral care composition such as dentifrice, are required to be effective in removing extrinsic stains, dental plaque, and food debris which builds up on the pellicle on the surface of teeth.

[0006] In general, the efficiency of physical removal of stain, plaque, and food debris can be increased by using an abrasive having increased abrasivity, or by increasing the level of abrasive incorporated into the composition. However, both these approaches also increase the risk that tooth surfaces may be damaged.

[0007] However, there is a continuing need for oral care compositions that demonstrate satisfactory levels of cleaning yet are not unduly abrasive and have damaging effect on the teeth.

[0008] Summary of the Invention

[0009] It has been surprisingly found that an oral care composition having a specific combination of natural calcium carbonate and precipitated calcium carbonate provides an improved cleaning performance while having a lower relative dentin abrasivity (RDA).

[0010] According to a first aspect of the present invention provided is an oral care composition comprising:

[0011] (i) natural ground calcium carbonate;

[0012] (ii) precipitated calcium carbonate; and, wherein the total content of natural ground calcium carbonate and the precipitated calcium carbonate ranges from 43 wt.% to 50 wt.% of the total composition and wherein the ratio of the natural ground calcium carbonate to the precipitated calcium carbonate ranges from 1 :1.1 to 1:1.5.

[0013] According to a second aspect of the present invention provided is use of natural ground calcium carbonate, and precipitated calcium carbonate in an oral care composition wherein the total content of natural ground calcium carbonate and the precipitated calcium carbonate ranges from 43 wt.% to 50 wt.% of the total composition and wherein the ratio of the natural ground calcium carbonate to the precipitated calcium carbonate ranges from 1:1.1 to 1:1.5 for enhancing cleaning performance and providing lower relative dentin abrasivity (RDA).

[0014] By the term "oral care composition" it is meant that the composition provides a benefit when used in the oral cavity. The oral care composition of the present invention may be in various forms including but not limited to paste, gel, prophy, dissolvable strip, dentifrice, tablet, a tape, floss, a mouthwash, mouth rinse, or a foam / foam-able product.

[0015] The term 'dentifrice" as used herein means a paste, gel, powder, tablets, or liquid formulations, unless otherwise specified, that are used to clean the surfaces of the oral cavity. Such a composition is not intentionally swallowed for purposes of systemic administration of therapeutic agents, but is applied to the oral cavity, used to treat the oral cavity, and then expectorated. Typically, such a composition is used in conjunction with a cleaning implement such as a toothbrush, usually by applying it to the bristles of the toothbrush and then brushing the accessible surfaces of the oral cavity.

[0016] The term "teeth" as used herein refers to natural teeth as well as artificial teeth or dental prosthesis.

[0017] 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”.

[0018] All amounts are by weight of the composition, unless otherwise specified.

[0019] It should be noted that in specifying any ranges of values, any upper value can be associated with any particular lower value.

[0020] 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. Detailed Description of the Invention

[0021] According to the first aspect of the present invention provided is an oral care composition including natural ground calcium carbonate and precipitated calcium carbonate.

[0022] Oral care composition

[0023] The oral care composition according to the first aspect of the present invention a natural ground calcium carbonate and precipitated calcium carbonate.

[0024] Preferably the oral care composition is a dentifrice composition which is a viscous material, more preferably the dentifrice composition is in the form of an extrudable semi-solid such as a cream, paste or gel (or mixture thereof). Still preferably the dentifrice composition is in the form of a toothpaste or gel form.

[0025] The toothpaste composition or gel composition may be single-phase composition or may be a combination of two or more separate toothpaste compositions. The toothpaste composition may be in any desired form, such as deep striped, surface striped, multilayered, having a gel format surrounding a paste format, or any combination thereof. Each toothpaste composition comprising two or more separate toothpaste compositions may be contained in a physically separated compartment of a dispenser and dispensed side-by-side.

[0026] Such a composition is not intentionally swallowed for purposes of systemic administration of therapeutic agents, but is applied to the oral cavity, used to treat the oral cavity, and then expectorated. Typically, such a composition is used in conjunction with a cleaning implement such as a toothbrush, usually by applying it to the bristles of the toothbrush and then brushing the accessible surfaces of the oral cavity.

[0027] The composition is a product which, during the normal course of usage, is not for the purpose of systemic administration or intentionally swallowed but is rather retained in the oral cavity for a time sufficient to contact substantially all of the dental surfaces and / or oral tissues for the purposes of oral activity.

[0028] A composition according to the invention will generally contain the following preferred ingredients to enhance performance and / or consumer acceptability, in addition to the ingredients specified above. Natural calcium carbonate

[0029] According to the first aspect the oral care composition according to the invention includes a natural calcium carbonate.

[0030] Natural calcium carbonate is preferably ground calcium carbonate or fine ground natural chalk ("FGNC") which are one of the more preferred calcium-containing abrasive useful in the present invention. Preferably the natural calcium carbonate is sourced from limestone or marble. FGNC may also be modified chemically or physically. Physical modification is typically by coating during milling or after milling by heat treatment. Typical coating material include but is not limited to magnesium stearate or oleate. The particle size distribution (PSD) of FGNC may also be modified during the milling process by using different milling techniques, for example, ball milling, air-classifier milling or spiral jet milling. Preferably the natural calcium carbonate according to the invention has a particle size ranging from 325 to 800 mesh, a mesh selected from 325, 400, 600, 800, or combinations thereof.

[0031] Preferably the natural calcium carbonate according to the invention has a weight average particle size ranging from 0.1 microns to 30 microns, preferably from 0.1 microns to 20 microns, still preferably from 5 microns to 20 microns.

[0032] Natural calcium carbonate abrasive is typically a finely ground limestone which may optionally be refined or partially refined to get a desired particle size distribution. Natural calcium carbonate preferably has a weight average particle size of less than 12 microns, e.g., 3 to 7 microns, e.g., about 5.5 microns.

[0033] Preferably the natural ground calcium carbonate has a D5o particle size ranging from 10 micrometers to 12 micrometers.

[0034] The natural ground calcium carbonate particle preferably has a D particle size 1 micrometers to 2 micrometers, still preferably from 1.2 micrometers to 2 micrometers, more preferably from 1.2 micrometers to 1.5 micrometers.

[0035] Natural calcium carbonate may contain a high proportion of relatively large particle of not carefully controlled dimension, which may unacceptably increase the abrasivity, preferably no more than 0.01 wt%, preferably no more than 0.004 wt.% by weight of the natural ground calcium carbonate particle would not pass through a 325 mesh. The natural ground calcium carbonate particle preferably has a D90 particle size of maximum 22 micrometers, still preferably not more than 20, more preferably not more than 18 micrometers.

[0036] Natural calcium carbonate has strong crystal structure and is thus much harder and more abrasive than precipitated calcium carbonate. The tapped density for the natural calcium carbonate is for example between 1 gm / cm3and 1.5 gm / cm3, e.g., about 1.2 gm / cm3for example about 1.19 gm / cm3. There are different polymorphs of natural calcium carbonate, e.g., aragonite, vaterite, and calcite. The natural ground calcium carbonate may be of any one or more of these different polymorph form.

[0037] More preferably the natural calcium carbonate is a refined natural calcium carbonate.

[0038] Preferably the amount of natural ground calcium carbonate in the composition ranges from 18 wt.% to 30 wt.%, more preferably the natural ground calcium carbonate is present in the composition in an amount ranging from 18 wt.% to 20 wt.%. Preferably the amount of natural ground calcium carbonate in the composition is not less than 20 wt.%, still preferably not less than 20.5 wt.%, more preferably not less than 21 wt.%, still more preferably not less than 21 .5 wt.%, but typically not more than 28 wt.%, preferably not more than 25 wt.% or still preferably not more than 24 wt.%, further preferably not more than 23 wt.%, most preferably not more than 22 wt.%.

[0039] Precipitated calcium carbonate

[0040] According to the first aspect of the present invention provided is an oral care composition which includes precipitated calcium carbonate. Precipitated calcium carbonate has a morphology which is different from the natural calcium carbonate.

[0041] Precipitated calcium carbonate is generally more friable and more porous, thus having lower abrasivity and higher water absorption. For use in the present invention, the precipitated calcium carbonate particles are small, e.g., having an average particle size of 1 to 5 microns, and e.g., no more than 0.1 percent, preferably no more than 0.05 percent by weight of particles which would not pass through a 325 mesh. The precipitated calcium carbonate particles may for example have a D50 of 3 to 10 microns, for example 3.8 to 4.9, e.g., about 4.3; a D50 of 1 to 4 microns, e.g., 2.2 to 2.6 microns, e.g., about 2.4 microns, and a D10 of 1 to 2 microns, e.g., 1.2 to 1.4, e.g., about 1.3 microns. The precipitated calcium carbonate particles have relatively high-water absorption, e.g., at least 25 g / 100 g, e.g., 30 to 70 g / 100 g. Preferably the precipitated calcium carbonate has a weight average particle size ranging from 1 micrometers to 10 micrometers, still preferably from 1 micrometers to 8 micrometers, still more preferably from 1 micrometers to 6 micrometers.

[0042] Preferably the precipitated calcium carbonate has a weight average particle size ranging from 1 micrometers to 5 micrometers, still preferably ranging from 1 micrometers to 4 micrometers, still preferably from 3.8 micrometers to 4.9 micrometers.

[0043] Preferably the precipitated calcium carbonate has an average particle size wherein no more than 0.1%, still preferably no more than 0.05% by weight of precipitated calcium carbonate particles which would not pass through a 325 mesh.

[0044] Preferably the precipitated calcium carbonate has a Dso particle size ranging from

[0045] 1 micrometers to 10 micrometers, still preferably from 1 micrometers to 8 micrometers, more preferably from 1 to 6 micrometers, still preferably from 3.8 micrometers to 4.9 micrometers, more preferably 3.8 micrometers to 4.3 micrometers. Preferably the Dso particle size is not less than 1.5 micrometers, still preferably not less than 2 micrometers, still preferably not less than 2.4 micrometers, still more preferably not less than 2.5 micrometers. Preferably the Dso particle size is not more than 5.5, still preferably not more than 5.3, further preferably not more than 4.9, still more preferably not more than 4.3 micrometers. Also preferred are the Dso particle size ranging from 1 to 4 micrometers, more preferably also from 2.2 to 2.6 micrometers.

[0046] The precipitated calcium carbonate particle preferably has a Dwparticle size ranging from 1 micrometers to 2 micrometers, still preferably from 1.2 micrometers to 1.4 micrometers, more preferably from 1.2 micrometers to 1.3 micrometers.

[0047] The precipitated calcium carbonate particles preferably have relatively high-water absorption, preferably a water absorption of at least 25 g / 100 g, more preferably still preferably a water absorption of 30 g / 100 g to 70 g / 100 g.

[0048] In some embodiments, additional calcium-containing abrasives, for example calcium phosphate abrasive, e.g., tricalcium phosphate, hydroxyapatite or dicalcium phosphate dihydrate or calcium pyrophosphate, and / or silica abrasives, sodium metaphosphate, potassium metaphosphate, aluminum silicate, calcined alumina, or other siliceous materials, or combinations thereof are used. The composition of the present invention preferably may be free or substantially free of silicate. Preferably the amount of precipitated calcium carbonate in the oral care composition ranges from 22 wt.% to 30 wt.%, more preferably the natural ground calcium carbonate is present in the composition in an amount ranging from 23 wt.% to 30 wt.%. Preferably the amount of natural ground calcium carbonate in the composition is not less than 22.5 wt.%, still preferably not less than 23 wt.%, more preferably not less than 24 wt.%, still more preferably not less than 25 wt.%, but typically not more than 29 wt.%, preferably not more than 28 wt.% or still preferably not more than 27 wt.%, further preferably not more than 26.5 wt.%, most preferably not more than 26 wt.%.

[0049] Total content of calcium carbonate in the oral care composition

[0050] According to the first aspect of the present invention, the oral care composition comprises a total content of natural calcium carbonate and precipitated calcium carbonate ranging from 43 wt.% to 50 wtof the total composition

[0051] The total content as used herein refers to the sum total of the amount of the natural calcium carbonate and the precipitated calcium carbonate present in the oral care composition.

[0052] Preferably the total content of the natural calcium carbonate and precipitated calcium carbonate in the oral care composition comprises at least 38 wt.%, still preferably at least 40 wt.%, still preferably at least 41 wt.%, most preferably at least 42 wt.% of the composition, but typically not more than 50 wt.%, still preferably not more than 48 wt.%, still further preferably not more than 47 wt.%, still more preferably not more than 45 wt.% based on the weight of the oral care composition.

[0053] Weight ratio of natural and precipitated calcium carbonate

[0054] The oral care composition has a weight ratio of the natural ground calcium carbonate to the precipitated calcium carbonate which ranges from 1:1.1 to 1 :1.5. More preferably the oral care composition has a weight ratio of the natural ground calcium carbonate to the precipitated calcium carbonate ranging from 1 :1.1 to 1:1.4, more preferably from 1 :1.1 to 1 :1.3.

[0055] Preferred ingredients

[0056] Flavouring agent:

[0057] According to the first aspect disclosed composition may preferably include a flavouring agent.

[0058] Flavouring agents may be added to the composition to make the experience of using the present composition more pleasant. The amount of flavouring agent is preferably from about 0.01% to about 10% by weight of the total composition, such as from about 0.1% to about 5% by weight of the total composition, such as from about 0.1% to about 4% by weight of the total 20 composition, such as from about 0.5% to about 5% by weight of the total composition, such as from about 1% to about 5% by weight of the total composition, such as from about 0.5% to about 4% by weight of the total composition, such as from about 0.5% to about 3% by weight of the total composition, such as from about 0.5% to about 2% by weight of the total composition, such as from about 0.5% to about 1.5% by weight of the total composition.

[0059] Any orally acceptable natural or synthetic flavoring agent can be used, including without limitation essential oils and various flavoring aldehydes, esters, alcohols, and similar materials, tea flavors, vanillin, sage, marjoram, parsley oil, spearmint oil, cinnamon oil, oil of Wintergreen, peppermint oil, clove oil, bay oil, anise oil, eucalyptus oil, citrus oils, fruit oils, sassafras and essences including those derived from lemon, orange, lime, grapefruit, apricot, banana, grape, apple, strawberry, cherry, pineapple, etc., bean-and nut-derived flavors such as coffee, cocoa, cola, peanut, almond, etc., adsorbed and encapsulated flavorants and the like. Also encompassed within flavoring agent herein are ingredients that provide fragrance and / or other sensory effect in the mouth, including cooling or warming effects. Such ingredients illustratively include menthol, carvone, menthyl acetate, menthyl lactate, camphor, eucalyptus oil, eucalyptol, anethole, eugenol, cassia, oxanone, a-irisone, thymol, linalool, benzaldehyde, cinnamaldehyde, N-ethyl-p-menthan-3-carboxamine, N, 2, 3-trimethyl-2- isopropylbutanamide, 3- (1-menthoxy) - propane-1 , 2-diol, cinnamaldehyde glycerol acetal (CGA), menthone glycerol acetal (MGA) and the like.

[0060] Polysaccharide:

[0061] According to the first aspect, disclosed oral care composition preferably includes a polysaccharide. Preferably the polysaccharide is selected from xanthan gum, carrageenan, cellulose, modified cellulose, guar gum and mixtures thereof.

[0062] Preferably the polysaccharide is carrageenan. Carrageenan belongs to a family of hydrocolloid polysaccharides. The carrageenan may be selected from lambda, kappa, and iota carrageenan. All carrageenan contains repeating galactose units joined by alternating 1-3 and a 1-4 glycosidic linkages and are partially sulfated. The types of carrageenan may be distinguished, in part, by their degree of sulfation. Kappa carrageenan has a repeating unit of D-galactose-4- sulfate-3,6-anhydro-D-galactose providing a sulfate ester content of about 18% to 25%. lota carrageenan has a repeating unit of D-galactose-4-sulfate-3,6-anhydro- D-galactose-2-sulfate providing a sulfate ester content of about 25% to 34%. Lambda carrageenan has a repeating unit of D-galactose-2-sulfate-D-galactose-2,6-disulfate providing a sulfate ester content of about 30 to 40%. Carrageenan generally form gels that are thixotropic. In the oral care composition of the present invention kappa carrageenan and iota carrageenan are particularly preferred, more preferably the carrageenan is an iota carrageenan.

[0063] Preferably the carrageenan has a molecular weight well in excess of 100,000 kDa (kilodaltons), and generally in the molecular weight range of 250,000 to 600,000 kDa, have been used to impart viscosity and rheological characteristics important for oral care composition particularly dentifrice composition, including desirable consistency, texture, stand-up, physical stability and low stringiness. Carrageenan of molecular weights below 100,000 kDa have also been reported and are suitable for use typically at higher levels because of their lower viscosity building capability.

[0064] The amount of carrageenan is preferably in an amount ranging from 0.01 wt.% to 1 wt.% in the composition, such as from about 0.1% to about 1% by weight of the total composition, such as from 0.1% to 0.9% by weight of the total composition, such as from 0.3% to about 0.8% by weight of the total composition.

[0065] Fluoride ion source:

[0066] The composition may include an effective amount of an anti-caries agent to prevent caries. In one example, the anti-caries agent is a fluoride ion source. The fluoride ion may be present in an amount sufficient to give a fluoride ion concentration in the composition at 25°C, and / or can be used at levels of from 0.0025%to 5%, from 0.005% to 2 0%, by weight of the composition, or different combinations of the upper and lower percentages described above or combinations of any integer in the ranges listed above to provide anti-caries effectiveness. Representative fluoride ion source includes stannous fluoride, sodium fluoride, potassium fluoride, amine fluoride, sodium monofluorophosphate, and zinc fluoride. In one example the dentifrice composition contains a fluoride source selected from stannous fluoride, sodium fluoride, and combinations thereof. The fluoride ion source may include sodium monofluorophosphate, and wherein the composition comprises 0,0025% to 2%, by weight of the composition, of the sodium monofluorophosphate, from 0.5% to 1.5%, from 0.6% to 1.7%, or different combinations of the upper and lower percentages described above or combinations of any integer in the ranges listed above. In another example, the composition comprises from 0.0025% to 2% by weight of the composition, of a fluoride ion source. In one example, the composition of the present invention may have a dual fluoride ion source, specifically sodium monofluorophosphate and an alkaline metal fluoride Without wishing to be bound by theory, such an approach may provide an improvement in mean fluoride uptake.

[0067] Compositions of the invention may include fluoride sources such as sodium fluoride, stannous fluoride, sodium monofluorophosphate, zinc ammonium fluoride, tin ammonium fluoride, calcium fluoride, cobalt ammonium fluoride and mixtures thereof.

[0068] Fluoride ion sources may be added to the compositions at a level of about 0.001 wt. percent to about 10 wt. percent, e.g., from about 0.003 wt. percent to about 5 wt. percent, 0.01 wt. percent to about 1 wt., or about 0.05 wt. percent. In some embodiment, the stannous fluoride is present in an amount of 0.1 wt. percent to 2 wt. percent (0.1 wt percent -0.6 wt. percent) of the total composition weight. Fluoride ion sources may be added to the compositions at a level of about 0.001 wt. percent to about 10 wt. percent, e.g., from about 0.003 wt. percent to about 5 wt. percent, 0.01 wt. percent to about 1 wt., or about 0.05 wt. percent. However, it is to be understood that the weights of fluoride salts to provide the appropriate level of fluoride ion will obviously vary based on the weight of the counter ion in the salt, and one of skill in the art may readily determine such amounts. In some embodiment, the fluoride source is a fluoride salt present in an amount of 0.1 wt. percent to 2 wt. percent (0.1 wt percent -0.6 wt. percent) of the total composition weight (e.g., sodium fluoride (e.g., about 0.32 wt. percent).

[0069] Some embodiments of the invention are free from fluoride sources, that is the composition comprises less than 0.01 wt% of a fluoride source.

[0070] Humectant:

[0071] Preferably the composition according to the present invention includes a polyol such as propylene glycol, xylitol, and lactitol. Glycerol is a preferred polyol; sorbitol is particularly preferred.

[0072] Antimicrobial agents:

[0073] Preferably the composition according to the present invention includes an antimicrobial agent. Composition according to the present invention comprise 0.5 wt.% to 5 wt.% of the total composition of an antimicrobial quaternary ammonium material. Preferred antimicrobial quaternary ammonium material are cetylpyridinium chloride (CPC), CPC-clay benzalkonium chloride, tetradecylpyridinium chloride (TPC), N-tetradecyl-4-ethylpyridinium chloride (TDEPC). Particularly preferred is a cetylpyridium chloride clay complex. In some embodiments, the oral care compositions comprise an effective amount of one or more antibacterial agents, for example comprising an antibacterial agent selected from halogenated diphenyl ether (e.g. triclosan), triclosan monophosphate, herbal extracts and essential oils (e.g., rosemary extract, tea extract, magnolia extract, thymol, menthol, eucalyptol, geraniol, carvacrol, citral, hinokitol, magnolol, ursolic acid, ursic acid, catechol, methyl salicylate, epigallocatechin gallate, epigallocatechin, gallic acid, miswak extract, sea-buckthorn extract), bisguanide antiseptics (e.g., chlorhexidine, alexidine or octenidine), quaternary ammonium compounds (e.g., cetylpyridinium chloride (CPC), CPC-claybenzalkonium chloride, tetradecylpyridinium chloride (TPC), N-tetradecyl-4-ethylpyridinium chloride (TDEPC)), phenolic antiseptics, hexetidine furanones, bacteriocins, ethyllauroyl arginate, arginine bicarbonate, a Camellia extract, a flavonoid, a flavan, halogenated diphenyl ether, creatine, sanguinarine, povidone iodine, delmopinol, salifluor, metal ions (e.g., zinc salts, stannous salts, copper salts, iron salts), propolis and oxygenating agents (e.g., hydrogen peroxide, buffered sodium peroxyborate or peroxycarbonate), phthalic acid and its salts, monoperthalic acid and its salts and esters, ascorbyl stearate, oleoyl sarcosine, alkyl sulfate, dioctyl sulfosuccinate, salicylanilide, domiphen bromide, delmopinol, octapinol and other piperidino derivatives, nisin preparations, chlorite salts; parabens such as methylparaben or propylparaben and mixtures of any of the foregoing. One or more additional antibacterial or preservative agents may optionally be present in the composition in a total amount of from about 0.01 wt. percent to about 0.5 wt. percent, optionally about 0.05 wt. percent to about 0.1 wt. percent or about 0.3 percent, by total weight of the composition.

[0074] Thickener:

[0075] Preferably the composition according to the present invention includes a thickener. The thickener is preferably an inorganic or a natural or synthetic thickener. Preferably the composition includes from 0.10 wt.% to 15 wt.% thickener, depending on the material chosen. These proportions of thickeners in the compositions of the present invention preferably form an extrudable, shape-retaining toothpaste composition which can be squeezed from a tube onto a toothbrush and will not fall between the bristles of the brush but rather, will substantially maintain its shape thereon. Suitable thickeners or gelling agents useful in the practice of the present invention include inorganic thickening silicas such as amorphous silicas available from Huber Corporation under the trade designation Zeodent 165, Irish moss, gum tragacanth, and polyvinylpyrrolidone. Further suitable binders and thickeners can be present and include sodium carboxymethylcellulose, hydroxyethyl cellulose (Natrosol®), xanthan gum, gum arabic etc. as well as synthetic polymers such as polyacrylates and carboxyvinyl polymers such as Carbopol®.

[0076] Polymeric deposition aid:

[0077] Preferably the composition according to the present invention includes a polymeric deposition aid. Preferably the composition comprises acid anhydride polymers, particularly preferred are co-polymers of maleic anhydride with methyl vinylether, in which the anhydride moiety may be in a partially or fully hydrolysed or alcoholysed form. Preferred copolymers include: Gantrez(R) polymers such as:

[0078] Gantrez S-95: molecular weight 216,000; free acid;

[0079] Gantrez S-96: molecular weight 700,000; free acid;

[0080] Gantrez S-97: molecular weight 1,500,000; free acid; and

[0081] Gantrez MS-955: molecular weight 1,060,000; calcium / sodium salt.

[0082] Particularly preferred co-polymers of maleic acid and methyl vinylether have a molecular weight of 1,000,000 or greater and an especially preferred material is Gantrez S-97.

[0083] Tooth whitening agent:

[0084] Preferably the composition according to the present invention includes a tooth whitening agent. The whitening agent preferably comprises a green and / or a blue pigment. In the context of the present invention a pigment is generally understood to be a shade / material which is insoluble in the relevant medium, at the relevant temperature. This is in contrast to dyes which are soluble. In the context of this invention, the "relevant medium" is human saliva, the liquid medium in which the composition is used, at the temperature of the oral cavity during brushing of the teeth, i.e. , up to 37°C. As a reasonable approximation, the relevant medium may be considered to be water and the relevant temperature to be 25°C.

[0085] Preferably the blue pigment is Pigment Blue 15, more preferably Pigment Blue 15:1, 15:2, 15:3, 15:4, 15:5 or 15:6, most preferably 15:1. A preferred pigment is blue pigment is Phthalocyanine Blue Pigment, Cl No. 74160, blue covarine.

[0086] The preferred Green pigment is Phthalocyanine Green, preferably Phthalocyanine Green CI- 74260.

[0087] Preferably the total level of pigment in the composition is from 0.01 wt% to 3 wt, more preferably from 0.02 to 2 wt%. If the composition is a toothpaste it may be a dual phase paste, with the whitening pigments present in one phase.

[0088] Metal salts:

[0089] Preferably the composition according to the present invention includes a water-soluble or sparingly water-soluble sources of metal salts. Preferred are zinc ions such as zinc chloride, zinc acetate, zinc gluconate, zinc sulphate, zinc fluoride, zinc citrate, zinc lactate, zinc oxide, zinc monoglycerolate, zinc tartrate, zinc pyrophosphate and zinc maleate; also preferred are stannous ions such as stannous fluoride and stannous chloride.

[0090] Oral care enzyme systems:

[0091] Preferably the composition according to the present invention includes an oral care enzyme systems such as hydrogen peroxide producing enzyme systems (e.g., the oxidoreductase enzyme glucose oxidase), amyloglucosidase, dextranase and / or mutanase, (optionally in the presence of zinc ion providing compounds and / or 8- hydroxyquinoline derivatives), lactoperoxidase, lactoferrin, lysozyme and mixtures thereof.

[0092] In one embodiment a preferred class of oral care active for inclusion in the compositions of the invention includes agents for the remineralisation of teeth. The term “remineralisation” in the context of the present invention means the in-situ generation of hydroxyapatite on teeth.

[0093] A specific example of a suitable agent for the remineralisation of teeth is a mixture of a calcium source and a phosphate source which, when delivered to the teeth results in the in-situ generation of hydroxyapatite on teeth.

[0094] Illustrative examples of the types of calcium source that may be used in this context (hereinafter termed “remineralizing calcium sources”) include, for example, calcium phosphate, calcium gluconate, calcium oxide, calcium lactate, calcium glycerophosphate, calcium carbonate, calcium hydroxide, calcium sulphate, calcium carboxymethyl cellulose, calcium alginate, calcium salts of citric acid, calcium silicate and mixtures thereof. Preferably the remineralizing calcium source is calcium silicate.

[0095] The amount of remineralizing calcium source(s) (e.g., calcium silicate) in the composition of the invention typically ranges from 1 to 30%, preferably from 5 to 20% by total weight remineralizing calcium source based on the total weight of the oral care composition. Illustrative examples of the types of phosphate source that may be used in this context (hereinafter termed “remineralizing phosphate sources”) include, for example, monosodium dihydrogen phosphate, disodium hydrogen phosphate, sodium pyrophosphate, tetrasodium pyrophosphate, sodium tripolyphosphate, sodium hexametaphosphate, potassium dihydrogenphosphate, trisodium phosphate, tripotassium phosphate and mixtures thereof. Preferably the remineralizing phosphate source is a mixture of trisodium phosphate and sodium dihydrogen phosphate.

[0096] The amount of remineralizing phosphate source(s) (e.g. trisodium phosphate and sodium dihydrogen phosphate) in the composition of this invention typically ranges from 2 to 15%, preferably from 4 to 10% by total weight remineralizing phosphate source based on the total weight of the oral care composition.

[0097] Thickening silica:

[0098] Preferably the composition according to the present invention includes a thickening silica. The thickening silica may be obtained from sodium silicate solution by destabilizing with acid as to yield very fine particles. It will be appreciated by a person skilled in the art that silicas used as thickening silicas are different from silicas used as abrasive silicas. One commercially available example for use as thickening silicas is ZEODENT® branded silicas from Huber Engineered Materials (eg., ZEODENT® 103, 124, 113 115, 163, 165, 167). Silicas suitable for use as abrasive silicas may include precipitated silica materials such as those marketed by the Huber Engineered Materials (e.g., ZEODENT® 119, 118, 109, 129).

[0099] Sweetener:

[0100] Preferably the composition according to the present invention includes a sweetener. In some Preferably the oral care composition includes at least one sweetener, useful for example to enhance taste of the composition. Sweetener among those useful herein include dextrose, polydextrose, sucrose, maltose, dextrin, dried invert sugar, mannose, xylose, ribose, fructose, levulose, galactose, corn syrup, partially hydrolyzed starch, hydrogenated starch hydrolysate, ethanol, sorbitol, mannitol, xylitol, maltitol, isomalt, aspartame, neotame, saccharin and salts thereof (e.g., sodium saccharin), sucralose, dipeptide-based intense sweeteners, cyclamates, dihydrochalcones.

[0101] One or more sweeteners are optionally present in a total amount depending strongly on the sweetener (s) selected, but typically 0.005 wt. percent to 5 wt. percent, by total weight of the composition, optionally 0.005 wt. percent to 0.2 wt. percent, further optionally 0.05 wt. percent to 0.1 wt. percent by total weight of the composition.

[0102] Plaque dispersing agent:

[0103] Preferably the composition according to the present invention includes a Plaque dispersing agent. Preferably the oral care compositions further comprise an agent that interferes with or prevents bacterial attachment, e.g., ethyl lauroyl arginiate (ELA), solbrol or chitosan, as well as plaque dispersing agents such as enzymes (papain, glucoamylase, etc.).

[0104] Mixtures of any of the above-described materials may also be used.

[0105] Other optional ingredients

[0106] The composition according to the invention may include ingredients which are common in the art, such as: a) antimicrobial agents, e.g., chlorhexidine, sanguinarine extract, metronidazole, quaternary ammonium compounds, such as cetylpyridinium chloride; cetylpyridium chloride clay complex bis-guanides, such as chlorhexidine digluconate, hexetidine, octenidine, alexidine; and halogenated bisphenolic compounds, such as 2,2' methylenebis-(4-chloro-6- bromophenol); b) anti-inflammatory agents such as ibuprofen, flurbiprofen, aspirin, indomethacin etc.; c) anti-caries agents such as sodium- and stannous fluoride, aminefluorides, sodium monofluorophosphate, sodium trimeta phosphate and casein; d) plaque buffers such as urea, calcium lactate, calcium glycerophosphate and strontium polyacrylates; e) vitamins such as Vitamins A, C, D, B (preferably B3) and E; f) plant extracts; g) plant-derivable antioxidants such as flavonoid, catechin, polyphenol, and tannin compounds and mixtures thereof; h) desensitising agents, e.g., potassium citrate, potassium chloride, potassium tartrate, potassium bicarbonate, potassium oxalate, potassium nitrate and strontium salts; i) anti-calculus agents, e.g., alkali-metal pyrophosphates, hypophosphite-containing polymers, organic phosphonates and phosphocitrates etc.; j) biomolecules, e.g., bacteriocins, antibodies, enzymes, etc.; k) proteinaceous materials such as collagen; l) preservatives; m) opacifying agents example, titanium dioxide; n) hyaluronic acid; o) amino acids such as arginine; p) colouring agents; q) pH-adjusting agents; r) mouth feel agents; s) pharmaceutically acceptable carriers, e.g., starch, sucrose, water, or water / alcohol systems etc.; t) surfactants, such as anionic, nonionic, cationic and zwitterionic or amphoteric surfactants; u) polymeric compounds which can enhance the delivery of active ingredients such as antimicrobial agents can also be included; v) buffers and salts to buffer the pH and ionic strength of the oral care composition; and w) bleaching agents such as peroxy compounds e.g., potassium peroxydiphosphate, effervescing systems such as sodium bicarbonate / citric acid systems, colour change systems, and so on. x) anti-calculus or anti-tartar agents, y) coloring agents.

[0107] Preferably the composition includes arginine.

[0108] According to a second aspect of the present invention disclosed is use of natural ground calcium carbonate, and precipitated calcium carbonate in an oral care composition wherein the total content of natural ground calcium carbonate and the precipitated calcium carbonate ranges from 35 wt.% to 50 wt.% and wherein the weight ratio of the natural ground calcium carbonate to the precipitated calcium carbonate ranges from 1:1.1 to 1 :1.5 for enhancing cleaning performance and lowering relative dentin abrasivity (RDA).

[0109] Examples

[0110] Example 1: Evaluation of cleaning composition of different toothpaste compositions

[0111] Evaluation of the Pellicle cleaning ratio

[0112] Specimen preparation:

[0113] Human, permanent, molars were cut to obtain buccal enamel specimens approximately 4 X 4 mm. The enamel specimens were embedded in an auto-polymerizing methacrylate resin so that only the enamel surfaces were exposed. The enamel surfaces were then smoothed and polished on a lapidary wheel and lightly etched to expedite stain accumulation and adherence. They were then placed on a rotating rod (~37°C incubator), which alternately exposed them to air and to a solution consisting of PGY broth, tea, coffee, mucin, FeCh, and Micrococcus luteus.

[0114] The staining broth was changed, and specimens were rinsed daily until a uniform stain had accumulated. After approximately seven days, a darkly stained pellicle film was apparent on the enamel surfaces. Specimens were rinsed, allowed to air dry, and refrigerated until used. All products were tested using specimens prepared at the same time.

[0115] Scoring and Set-Up:

[0116] The amount of in vitro stain was graded photometrically using the L value of the L*a*b* scale using a spectrophotometer (Minolta CM2600d). The area of the specimens scored was a 1 / 4- inch diameter circle in the center of the 10 X 10 mm enamel. Specimens with scores between 30 and 42 (30 being more darkly stained) were used. On the basis of these scores, the specimens were divided into groups of 16 specimens each, with each group having approximately the same average baseline score.

[0117] Procedure:

[0118] The specimens were mounted on a mechanical V-8 cross-brushing machine equipped with soft nylon filament toothbrushes. Tension on the enamel surface was adjusted at 150 g. A slurry of the toothpaste composition to be tested was prepared by mixing 25 grams of toothpaste composition with 40 mL of deionized water. The Standard Reference Material was tested as slurry by mixing 10 grams of reference silica with 50mL 0.5% CMC solution. The specimens were brushed for 800 strokes (4.5 minutes). To minimize mechanical variables, two specimens per group were brushed on each of the eight brushing heads. Fresh toothpaste composition slurry was made after being used to brush four specimens. Following brushing, specimens were rinsed, blotted dry, and scored again for stain, as previously described. The same procedure was used for testing other toothpaste composition in the study.

[0119] Calculations:

[0120] The mean decrement between the pre- brushing and post-brushing stain scores was determined for the Standard Reference Material group and assigned a pellicle cleaning ratio (PCR) value of 100. A constant value was calculated by dividing the mean decrement (corrected for the use of silica instead of Ca2P2O? as reference 3) of the Standard Reference Material into 100. The individual PCR value for each specimen was calculated by multiplying its individual decrement by the calculated constant. The mean, standard deviation, and SEM (standard error of the mean) for each test group (n=16) were then calculated using the individual PCR values.

[0121] The higher the PCR value, the greater the amount of stained pellicle removed from the enamel surface in this test.

[0122] Data analysis

[0123] The data was analyzed using one-way analysis of variance model [IBM SPSS Statistics Software], Data was further analyzed doing all pairwise multiple comparison procedures (Student-Newman-Keuls method). All analyses were done with the significance level set at 0.05.

[0124] Result

[0125] The composition of the different toothpaste composition studied, and the results obtained for each toothpaste composition are provided in table 1. The levels of all other ingredients was same in both the toothpaste composition and the compositions were made to 100 wt.% using distilled water.

[0126] Evaluation of the Relative dentin abrasion

[0127] Eight (8) human dentin specimens were subjected to neutron bombardments resulting in the formation of radioactive phosphorus (32P) within the specimens under the controlled conditions outlined by the ADA. The specimens were mounted in methyl methacrylate, so that they fit in a V-8 cross-brushing machine. The specimens were brushed for 1500 strokes, precondition run using slurry consisting of 10g Standard Reference Material 1 in 50 ml of a 0.5% CMC glycerin solution. The brushes used were those specified by the ADA with a brush tension of 150g.

[0128] Procedure

[0129] Following the precondition run, the test was performed using the above parameters (150g and 1500 strokes) in a “sandwich design.” Before and after brushing with each toothpaste composition (25 g toothpaste composition dissolved in 40 mL water) each tooth set was brushed with the Standard Reference Material (10g of ISO Reference Silica / 50ml 0.5% CMC). The procedure was repeated additional times so that each toothpaste was assayed on each tooth set. The treatment design was the modified Latin Square design so that no treatment followed another treatment consistently. Calculations

[0130] One mL sample was taken, each weighed (~1g), and added to 5 ml of “Ultima Gold’ scintillation cocktail. The samples were mixed well and immediately put on a liquid scintillation counter for radiation detection. Following counting, the net counts per minute (CPM) values were divided by the weight of the sample to calculate a net CPM / gram of slurry. The net CPM / g of the pre and post Standard Reference Material were multiplied by a correction factor 2 and then averaged to use in the calculation of RDA (relative dentin abrasion) for the test material. The Standard Reference Material was assigned a value of 100 and its ratio to the test material calculated.

[0131] Data analysis

[0132] Data was analyzed using a one-way analysis of variance model [IBM SPSS Statistics Software], Additional all pair wise comparisons were done using the StudentNewman-Keuls method. All analyses were done with the significance level set at 0.05.

[0133] Result

[0134] The obtained RDA mean values (± Standard Error of the Mean) are provided in the table 1. Higher values of RDA indicates higher abrasion.

[0135] Table 1

[0136] The data provided in table 1 shows that the cleaning performance of a toothpaste composition according to the present invention (Ex 1) having a total content of natural ground calcium carbonate and the precipitated calcium carbonate within the claimed ranges (45 wt.%) and where the weight ratio of the natural ground calcium carbonate to precipitated calcium carbonate is 1.1.25 (within claimed ranges of 1:1.1 to 1 :1.5) provides for better cleaning performance and surprisingly has lowered relative dentin abrasion as compared to the comparative composition (Ex A) which lies outside these claimed weight ratio ranges.

Claims

CLAIMS1. An oral care composition comprising:(i) natural ground calcium carbonate;(ii) precipitated calcium carbonate; and, wherein the total content of natural ground calcium carbonate and the precipitated calcium carbonate ranges from 43 wt.% to 50 wt.% of the total composition and wherein the weight ratio of the natural ground calcium carbonate to precipitated calcium carbonate to the ranges from 1 :1.1 to 1 :1.5.

2. A composition according to claim 1 or 2 wherein the weight ratio of the natural ground calcium carbonate to precipitated calcium carbonate ranges from 1:1.1 to 1 :1.3.

3. A composition according to any one of the preceding claims wherein the natural ground calcium carbonate is selected from the group consisting of fine ground calcium carbonate, refined calcium carbonate or mixtures thereof.

4. A composition according to any one of the preceding claims wherein the natural ground calcium carbonate has a weight average particle size ranging from 0.1 to 30 microns, preferably from 0.1 to 20 microns, still preferably from 5 to 20 microns.

5. A composition according to any one of the preceding claims wherein the precipitated calcium carbonate has a weight average particle size ranging from 1 micrometers to 10 micrometers, more preferably from 1 to 8 micrometers, still preferably from 1 to6 micrometers.

6. A composition according to any one of the preceding claims, wherein the composition comprises an antimicrobial quaternary ammonium material or a clay complex thereof, preferably antimicrobial quaternary ammonium material is cetylpyridium chloride, more preferably cetylpyridium chloride clay complex.

7. A composition according to any one of the preceding claims, wherein the composition comprises a zinc salt, stannous salt, or mixtures thereof.

8. A composition according to any one of the preceding claims, wherein the composition comprises a humectant, preferably the humectant is sorbitol.

9. A composition according to any one of the preceding claims wherein the ground natural calcium carbonate is present in an amount ranging from 18 wt.% to 20 wt.% in the composition.

10. A composition according to any one of the preceding claims wherein the precipitated calcium carbonate is present in an amount ranging from 22 wt.% to 30 wt.% in the composition.

11. A composition according to any one of the preceding claims wherein the composition comprises a flavouring agent, preferably the flavouring agent is present in an amount ranging from 0.01 wt.% to 10 wt.% in the composition.

12. A composition according to any one of the preceding wherein the composition comprises a thickener, preferably in an amount ranging from 1 wt.% to 5 wt.%, still preferably the thickener is a hydrated silica.

13. Use of natural ground calcium carbonate and precipitated calcium carbonate in an oral care composition wherein the total content of natural ground calcium carbonate and the precipitated calcium carbonate ranges from 43 wt.% to 50 wt.% and wherein the ratio of the natural ground calcium carbonate to the precipitated calcium carbonate ranges from 1:1.1 to 1:1.5, for improving the cleaning efficacy in the oral care composition.

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