Dentifrice composition

Abstract

The present invention relates to a single-phase dentifrice composition capable of stabilizing two mutually incompatible oral care actives.

Description

Technical Field

[0001] The present invention relates to oral care compositions, and in particular to dentifrice (preferably toothpaste) formulations. The present invention relates to a stable dentifrice composition containing two active substances with different stability requirements. Background Art

[0002] Toothpaste formulations with potassium nitrate can provide daily sensitivity protection.

[0003] Potassium is a clinically proven ingredient for reducing dentin hypersensitivity. See: Jeandot J et al. Clinic (French) 2007; Leight RS et al. J Clin Dent 2008; Nagata T et al., J Clin Periodontol 1994; Silverman G. Compend Contin Educ Dent 1985;6:13 1-133,136 and Silverman G et al. Am JDent 1994;7(1):9-12.

[0004] Potassium nitrate formulations build protection over time to help desensitize the nerves in the dental pulp.

[0005] Potassium ions can travel from the tooth surface into the exposed dentinal tubules to reach the internal nerves. Over time, the accumulation of potassium ions helps desensitize the nerves in the dental pulp, making them non-responsive to sensitivity stimuli (such as cold water, hot coffee, etc.).

[0006] Stannous fluoride is also an active ingredient often used in toothpaste to achieve reduced dentin hypersensitivity and other benefits.

[0007] Stannous fluoride has a different mode of action for reducing dentin sensitivity compared to potassium nitrate. It is believed that stannous fluoride accelerates the occlusion of exposed dentinal tubules.

[0008] There has long been a desire to use a combination of these two active substances in a single-phase toothpaste to achieve excellent sensitivity control.

[0009] However, this has never been satisfactorily achieved. The main reason is that the two active substances have very specific and opposite formulation requirements. Potassium nitrate is an inorganic salt and thus requires, usually, a highly polar formulation and most preferably an aqueous formulation for stabilization. In contrast, stannous fluoride is generally unstable in a (neutral) aqueous environment. Stannous fluoride is mainly commercially available in non-aqueous formulations (such as the Sensodyne® range of toothpastes) to prevent unacceptable levels of decomposition on the shelf.

[0010] Previously, toothpaste compositions using these two active substances at therapeutically effective levels required the use of a two-component paste. It was commonly used in striped toothpaste. One formulation was optimized for one active ingredient, while the other was optimized for the other active ingredient. These remained separate in the tube until dispensed onto the brush.

[0011] The object of the present invention is to solve this problem and provide an effective and stable single-phase toothpaste that provides these benefits. Summary of the Invention

[0012] The present invention includes a single-phase non-aqueous dentifrice composition comprising: glycerin, potassium nitrate, stannous fluoride, pyrogenic silica, and at least one hydroxyethyl cellulose polymer.

[0013] In another embodiment of the present invention, the weight-average molecular weight (Da) of the hydroxyethyl cellulose polymer is between about 500,000 and about 1,000,000 Da, preferably between about 600,000 and about 900,000 Da, more preferably between about 650,000 and about 800,000 Da, and most preferably between about 700,000 and about 750,000 Da.

[0014] In another embodiment, the hydroxyethyl cellulose polymer accounts for about 0.05 wt% to about 1 wt%, more preferably about 0.1 wt% to about 0.5 wt%, and most preferably about 0.2 wt% to about 0.4 wt%.

[0015] In another embodiment, pyrogenic silica is present in an amount of about 1 wt% to 6 wt%, more preferably about 2 wt% to about 4 wt%.

[0016] In another embodiment, glycerin accounts for at least about 50 wt% of the composition, more preferably at least about 60 wt%, and most preferably at least 70 wt%.

[0017] In another embodiment, potassium nitrate accounts for about 1 wt% to about 8 wt% of the total formulation, more preferably about 3 wt% to about 7 wt%, and most preferably about 5 wt%.

[0018] In another embodiment, stannous fluoride accounts for about 0.1 wt% to about 1 wt% of the formulation, preferably about 0.3 wt% to about 0.7 wt%, and most preferably about 0.4 wt% to about 0.6 wt%.

[0019] In another embodiment, the composition further comprises one or more surfactants, wherein the one or more surfactants account for about 0.5 wt% to about 5 wt%, preferably 1.0 wt% to 4.0 wt%, and most preferably about 2.0 wt% to about 3.0 wt%.

[0020] In another embodiment, the one or more surfactants include anionic surfactants.

[0021] In another embodiment, the surfactant is sodium lauryl sulfate (SLS).

[0022] In another embodiment, the composition further comprises a thickening gum in the composition of between about 0.05% and about 5% by weight, more preferably between about 0.075% and about 1% by weight, and most preferably between about 0.1% and about 0.5% by weight.

[0023] In another embodiment, the thickening gum includes carrageenan.

[0024] In another embodiment of the present invention, the composition comprises one or more silicas, wherein the total silica content is from about 1% to about 20% by weight, preferably from about 5% to about 15% by weight.

[0025] In another embodiment, the composition further comprises from about 0.5% to about 10% by weight, preferably from about 2.5% to about 7.5% by weight, and most preferably about 5% by weight of one or more stain removal components.

[0026] In another embodiment, the composition further comprises one or more additional ingredients selected from the categories of flavoring agents, sweetening agents, coloring agents, and preservatives. Detailed Description

[0027] The applicant has surprisingly discovered a non-aqueous single-phase dentifrice formulation that is stable at therapeutic levels of both potassium nitrate and stannous fluoride.

[0028] A dentifrice is a powder, paste, or liquid composition for cleaning teeth. The most common form of dentifrice is toothpaste.

[0029] This formulation provides excellent shelf-life stability and consumer acceptability.

[0030] It is well known that stannous fluoride can cause coloring problems and can cause toothpaste to turn yellow. This is thought to be the result of chemical decomposition and interaction, but the exact mechanism is not clear. The formulation of the present invention provides significant resistance to this degradation effect, and no discoloration has been observed even during long-term storage.

[0031] The non-aqueous nature of the present invention refers to a total water content of less than about 5% by weight, preferably less than about 2.5% by weight and most preferably less than about 1% by weight of water.

[0032] The dentifrice formulation of the present invention is based on a combination of glycerol as a solvent, at least one hydroxyethyl cellulose polymer as a thickener, and pyrogenic silica.

[0033] Glycerol (also known as glycerin or trihydroxypropane) is a simple polyol compound. It is a colorless, odorless, viscous liquid with a sweet taste and is non-toxic.

[0034] The dentifrice composition of the present invention contains at least about 50% by weight of glycerol, preferably at least about 60% by weight of glycerol, and most preferably at least about 70% by weight of glycerol.

[0035] It is well known that commercially available glycerol can contain about 0.1% to about 2.0% by weight of water bound to glycerol. Generally, this amount is <0.5%, for example, about 0.1% to about 0.5% by weight of glycerol. This small amount of water is bound to glycerol and thus cannot be used for other components. Those skilled in the art would still consider a composition containing glycerol to be non-aqueous. In any case, the solvent should be as anhydrous as possible.

[0036] Hydroxyethyl cellulose is a gelling and thickening agent derived from the natural polymer cellulose.

[0037] Cellulose is an organic compound with the formula (C6H 10 O5) n and is a polysaccharide composed of a straight chain of hundreds to thousands of β(1→4)-linked D-glucose units. Cellulose is an important structural component of the primary cell walls of green plants, many forms of algae, and oomycetes. Cellulose is the most abundant organic polymer on Earth.

[0038] Hydroxyethyl cellulose polymers are widely used in cosmetics, cleaning solutions, and other household products.

[0039] Hydroxyethyl cellulose polymers are commercially available products and have a wide variety of different specifications. For the purposes of the present invention, hydroxyethyl cellulose polymers with a weight-average molecular weight (in daltons or Da) between 500,000 and 1,000,000 Da are preferred.

[0040] More preferably, hydroxyethyl cellulose polymers with a weight-average molecular weight between 600,000 Da and 900,000 Da and most preferably between 700,000 Da and 800,000 Da.

[0041] A particularly preferred hydroxyethyl cellulose polymer for use in the formulations of the present invention is Natrosol TM 250, pharmaceutical grade, manufactured by Ashland. The polymer has a molecular weight of approximately 720,000 Da.

[0042] Preferably, the hydroxyethyl cellulose polymer accounts for 0.05% - 1% by weight of the total dentifrice composition, more preferably 0.1% - 0.5% by weight, and most preferably 0.2% - 0.4% by weight.

[0043] In the dentifrice composition of the present invention, the weight ratio of glycerol to hydroxyethyl polymer is from about 2000:1 to about 60:1, preferably from about 1500:1 to about 120:1, and most preferably from 750:1 to about 200:1, and most preferably from about 500:1 to about 250:1.

[0044] Particularly preferably, the dentifrice composition of the present invention contains a weight ratio of glycerol to hydroxyethyl cellulose of about 300:1. This provides a single-phase base formulation that can stabilize the therapeutic levels of both potassium nitrate and stannous fluoride.

[0045] The composition of the present invention requires fumed silica to achieve stability.

[0046] Fumed silica (also known as pyrogenic silica because it is produced in a flame) consists of microscopic droplets of amorphous silica that fuse into branched, chain-like, three-dimensional secondary particles, which then aggregate into tertiary particles. The resulting powder has a very low bulk density and a high surface area.

[0047] Preferably, the specific surface area of the fumed silica of the present invention is at least 150 m 2 / g, and more preferably at least 200 m 2 / g

[0048] Particularly preferred fumed silica is Aerosil® 200 sold by Evonik chemical company. Aerosil® 200 is hydrophilic fumed silica with a specific surface area of 200 m 2 / g. Another preferred fumed silica is Aerosil® 300 sold by Evonik chemical company. Aerosil® 300 is hydrophilic fumed silica with a specific surface area of 300 m 2 / g.

[0049] Other suitable sources of fumed silica include: Cabot Corporation (Cab-O-Sil®), Wacker Chemie (HDK®), Dow Corning, Heraeus (Zandosil®), Tokuyama Corporation (Reolosil®), OCI (Konasil®), Orisil (Orisil), and Xunyuchem (XYSIL®)

[0050] Preferably, fumed silica is present in the formulation in an amount of about 1% to about 6% by weight, more preferably about 2% to about 4% by weight.

[0051] Potassium nitrate can be used at a wide range of different concentrations.

[0052] Potassium nitrate is found in the dentifrices of the present invention at about 1% to 8% by weight, preferably about 3% to 7% by weight.

[0053] The therapeutic clinical effect of potassium nitrate in the dentifrice composition is typically observed at about 5% by weight. This is a particularly preferred amount in the present invention.

[0054] Stannous fluoride can also be tolerated and is stable at a wide range of different concentrations in the compositions of the present invention.

[0055] The amount of stannous fluoride that can be used in commercially available toothpastes is highly regulated by law and also varies in different legal jurisdictions, but the formulations of the present invention are stable to all of these and are also stable at concentrations far above those permitted by law.

[0056] Stannous fluoride can be used as follows, from about 0.1% to about 3% by weight, preferably from about 0.2% to about 2.0% by weight, more preferably from about 0.3% to about 1.0% by weight, and most preferably from about 0.4% to 0.7% by weight.

[0057] A particularly preferred content of stannous fluoride for commercially available toothpastes is 0.454% or 1100 ppm. Other preferred levels are 1450 ppm and 900 ppm.

[0058] Optional ingredients that can be used to confer further stability are aliphatic polyethers. Preferred polyethers include polyethylene glycol (PEG) and polypropylene glycol (PPG) or combinations thereof.

[0059] If included in the formulations of the present invention, PEG or PPG is preferably included at between 1% and 25% by weight of the formulation, preferably between 5% and 15% by weight.

[0060] The formulations of the present invention can contain one or more additional thickeners and one or more additional solvents. Optionally, a dentally acceptable abrasive can be included in a non-aqueous carrier.

[0061] Advantageously, thickeners can be present in the formulation to adjust the rheology to that of a conventional tube-based dentifrice.

[0062] Suitably, the thickener comprises an additional polymer. One possible polymer type is a carboxyvinyl polymer, such as carbomer. Carbomers include synthetic high molecular weight cross-linked polymers of acrylic acid. The polymer chains formed from the repeating units of acrylic acid can be cross-linked with, for example, allyl sucrose to provide a polymer that can be marketed as CarbopolTM A commercially available form of Carbopol; an ether of pentaerythritol to provide Carbopol TM A commercially available form of Carbopol 974; or with divinyl glycol, available as Noveon TM AA-1 is commercially available in a form manufactured by B.F. Goodrich as Carbopol. In one embodiment, the carboxyvinyl polymer comprises Carbopol TM 974. The carboxyvinyl polymer can be present in the non-aqueous composition in the range of about 0.1 to about 7.5 weight %. In one embodiment, the carboxyvinyl polymer is present in the composition in an amount of about 0.3 to about 1.0 weight %.

[0063] Suitably and additionally or alternatively, the composition according to the invention can comprise at least one inorganic thickener, such as thickening silica. Suitably, the thickener is thickening silica, such as colloidal hydrated silica, such as commercially available as Sident 22S or Syloid 244FP.

[0064] The composition of the invention can comprise a mixture of two or more different grades of silica having different thickening and abrasive properties.

[0065] In one embodiment, the total amount of thickening and / or abrasive silica is present in the non-aqueous composition in the range of about 0 to about 15 weight %, suitably about 5.0 to about 15.0 weight %.

[0066] The toothpaste composition of the invention preferably contains at least one surfactant.

[0067] At least one surfactant can be any surfactant known for use in oral care compositions.

[0068] A particularly preferred class of surfactants is anionic surfactants, more particularly those of the C 10-20 alkyl sulfate surfactant class.

[0069] The alkyl sulfate surfactant for use in the invention has the following structural formula:

[0070] R 1 OSO3M

[0071] R 1 represents the fatty alcohol moiety, M represents sodium, potassium, ammonium or triethanolamine. Fatty alcohols having a carbon chain length of about 10 to about 20, including those derived from coconut oil, palm oil and tall oil. In one embodiment, the fatty alcohol is lauryl alcohol. In one embodiment, the sodium salt is used. In one embodiment, the alkyl sulfate is sodium lauryl sulfate.

[0072] The alkyl sulfate surfactant may be present in an amount of about 0.1% to about 10% of the non-aqueous composition. In one embodiment, the alkyl sulfate surfactant may be present in an amount of about 0.1 wt% to about 5 wt% of the single-phase non-aqueous composition. In one embodiment, the alkyl sulfate surfactant is present in an amount of about 0.5 wt% to about 2.0 wt% of the non-aqueous composition.

[0073] The most preferred surfactant among these is sodium lauryl sulfate.

[0074] Sodium lauryl sulfate may specifically be present in an amount of about 0.1 wt% to about 3 wt%, preferably about 0.5 wt% to about 2.5 wt%, and most preferably about 1 wt% to about 2 wt%.

[0075] Another preferred surfactant for use in the compositions according to the invention is the taurate surfactant. The taurate surfactants useful in the present invention are salts of fatty acid amides of N-methyl taurine. They generally conform to the following structural formula:

[0076] RC(O)N(CH3)CH2CH2SO3M

[0077] where RC(O)- represents a fatty acid group and M represents sodium, potassium, ammonium or triethanolamine. Fatty acids having a carbon chain length of 10 to 20 are used, including those derived from coconut oil, palm oil and tall oil. In one embodiment, the fatty acid is derived from coconut. In one embodiment, the sodium salt is used. In one embodiment, the taurate is sodium methyl cocoyl taurate. This taurate surfactant is sold by Croda under the trade mark Adinol® CT.

[0078] The taurate surfactant may be present in an amount of about 0.1% to about 10% of the non-aqueous composition. In one embodiment, the taurate surfactant is present in an amount of about 0.1 wt% to about 5.0 wt% of the non-aqueous composition. In one embodiment, the taurate surfactant is present in an amount of about 0.5 wt% to about 2.0 wt% of the non-aqueous composition.

[0079] Another class of surfactants suitable for the compositions of the present invention belongs to the class of compounds known as betaines. Structurally, betaine compounds contain anionic functional groups such as carboxylate functional groups and cationic functional groups such as quaternary nitrogen functional groups separated by a methylene moiety. They include n-alkyl betaines, such as cetyl betaine and behenyl betaine, and n-alkylamidobetaines, such as cocamidopropyl betaine. In one embodiment, the betaine is cocamidopropyl betaine, which is commercially available under the trade name Tego Betain. Suitably, the betaine is present in an amount ranging from about 0.05 wt% to about 4 wt% of the non-aqueous composition, such as in a range from about 0.2 wt% to about 2.0 wt% of the non-aqueous composition.

[0080] The compositions according to the present invention may also comprise a surfactant system. The surfactant system consists of a first surfactant and at least a single second surfactant. In certain embodiments, the surfactant system consists of a first surfactant and a second surfactant, wherein the second surfactant consists of a mixture of two or more surfactants.

[0081] In certain embodiments, the surfactant system consists of a mixture of at least two surfactants from the list of betaines, taurates, alkyl sulfates and mixtures thereof.

[0082] Preferably, the formulations of the present invention include at least one anti-calculus ingredient or agent.

[0083] It is known that polyphosphates help to delay calculus formation and are examples of anti-calculus agents suitable for the dentifrice compositions of the present invention. Polyphosphates are generally understood to consist of two or more phosphate groups arranged mainly in a linear configuration, although some cyclic derivatives may be present. The polyphosphates used in the present invention include pyrophosphates, polyphosphates having three or more polyphosphate groups (such as sodium tripolyphosphate) and polyphosphates having four or more polyphosphate groups (such as tetrapolyphosphates and hexametaphosphates, etc.).

[0084] The polyphosphates may be used in the composition in an amount from about 1 wt% to about 12 wt%, preferably from about 2 wt% to about 10 wt%, and more preferably from about 3 wt% to about 7 wt%.

[0085] A particularly preferred polyphosphate for use in the present invention is sodium tropolyphosphate.

[0086] Other chemical anti-calculus ingredients may be used as needed.

[0087] Other examples of such ingredients include sodium pyrophosphate and sodium hexametaphosphate.

[0088] The toothpaste composition of the present invention may further comprise a bioactive glass component.

[0089] Examples of such additives are bioactive types of glass disclosed in WO 96 / 10985, WO 97 / 27158, and WO 99 / 13852. In an aqueous environment, such bioactive glass releases ions, causing a significant increase in pH, which may adversely affect the stability of any excipients contained in the dentifrice (especially during long-term storage). Formulating the bioactive silica-based glass in the non-aqueous dentifrice of the present invention prevents the release of ions within the dentifrice, thereby controlling the pH and increasing the long-term storage stability of the dentifrice.

[0090] In one embodiment, the bioactive glass for use in the present invention has a composition consisting of about 45 wt% silica, about 24.5 wt% sodium oxide, about 6 wt% phosphorus oxide, and about 24.5 wt% calcium oxide. One such bioactive glass is commercially available under the trade name NovaMin®, also known as 45S5 Bioglass®.

[0091] The bioactive glass may be present in an amount ranging from about 1 wt% to about 20 wt% of the non-aqueous composition. In one embodiment, the bioactive glass is present in an amount from about 1 wt% to about 15 wt% of the non-aqueous composition. In an alternative embodiment, the bioactive glass in the non-aqueous composition is present in an amount from about 1% to about 10% by weight of the non-aqueous composition. In another alternative embodiment, the bioactive glass is present in an amount from about 2 wt% to about 8 wt% of the non-aqueous composition.

[0092] Dentally acceptable abrasives may optionally be added to the non-aqueous composition of the present invention. Advantageously, the presence or absence of dentally acceptable abrasives and the amount of such abrasives can be used to selectively control the abrasive level of the dentifrice composition prepared by the present invention. For example, if present, the bioactive glass can provide an acceptable level of abrasion for the non-aqueous composition depending on the end use. Further by way of example, a desired amount of dentally acceptable abrasive can be added to increase the abrasive level of the entire non-aqueous composition.

[0093] Abrasives suitable for use in the non-aqueous compositions of the present invention include, for example, amorphous, gelled, precipitated, or pyrogenic silica, zinc orthophosphate, sodium bicarbonate (baking soda), plastic particles, alumina, hydrated alumina, calcium carbonate, calcium pyrophosphate, insoluble metaphosphates, or mixtures thereof.

[0094] The silica abrasive can be natural amorphous silica, such as diatomaceous earth; or synthetic amorphous silica, such as precipitated silica. For example, the silica abrasive includes those sold under the following trade names Zeodent®, Sident®, Sorbosil® or Tixosil® by Huber, Degussa, Ineos and Rhodia respectively.

[0095] Suitably, the silica abrasive is present in an amount of at most about 25% by weight of the total composition, such as about 2% to about 20% by weight of the total composition, such as about 5% to about 15% by weight.

[0096] The formulations of the present invention contain stannous fluoride. An additional fluoride source may also be included to adjust the fluoride to the desired level. Suitable fluoride ion sources for the compositions of the present invention include alkali metal fluorides such as sodium fluoride, alkali metal monofluorophosphates such as sodium monofluorophosphate, stannous fluoride or amine fluorides, in an amount to provide 25 ppm - 3500 ppm, preferably 100 - 1500 ppm of fluoride ions.

[0097] The compositions of the present invention may also contain an anti - erosion agent, such as the polymeric mineral surface - active reagent described in WO 04 / 054529 (Procter & Gamble).

[0098] The compositions of the present invention will contain additional formulating agents, such as flavoring agents, sweetening agents, opacifying agents or coloring agents and preservatives, selected from those conventionally used for this purpose in the field of oral hygiene compositions. Generally, these additional formulating agents may be used in small amounts or low proportions of the entire formulation. For example, such components are typically present in non - aqueous compositions in an amount of about 0.001% to about 5% by weight.

[0099] Dental care compositions generally have a viscosity suitable for the oral cavity. The viscosity will vary depending on the type of dental care composition prepared and its end - use. Based on the teachings provided herein, those skilled in the art can readily prepare compositions having a viscosity suitable for use in the oral cavity.

[0100] The compositions according to the present invention can be prepared by mixing the ingredients in any convenient order in appropriate relative amounts.

[0101] The present invention is further illustrated by the following examples.

[0102] Examples

[0103] Table 1

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[0105] Table 2

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[0107] Table 3

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[0109] Table 4

[0110]

[0111] All of the examples showed the required level of stability in terms of the active substance level and visible paste stability (no syneresis or significant discoloration) in an accelerated test (3M, 40 °C and 75% relative humidity).

Claims

1. A single-phase non-aqueous dentifrice composition comprising: glycerol, potassium nitrate, stannous fluoride, pyrogenic silica, and at least one hydroxyethyl cellulose polymer.

2. The single-phase non-aqueous dentifrice composition according to claim 1, wherein the weight average molecular weight (Da) of the hydroxyethyl cellulose polymer ranges from 500,000 Da to 1,000,000 Da, preferably from 600,000 Da to 900,000 Da, more preferably from 650,000 Da to 800,000 Da, and most preferably from 700,000 Da to 750,000 Da.

3. The single-phase non-aqueous dentifrice composition according to claim 1 or claim 2, wherein the hydroxyethyl cellulose polymer is present in an amount of 0.05 wt% to 1 wt%, more preferably 0.1 wt% to 0.5 wt%, and most preferably 0.2 wt% to 0.4 wt%.

4. The dentifrice according to any one of the preceding claims, wherein the pyrogenic silica is present in an amount between 1 wt% and 6 wt%, more preferably between 2 wt% and 4 wt%.

5. The single-phase non-aqueous dentifrice composition according to any one of the preceding claims, wherein the glycerol comprises at least 50 wt% of the composition, more preferably at least 60 wt%, and most preferably at least 70 wt%.

6. The single-phase non-aqueous dentifrice composition according to any one of the preceding claims, wherein the potassium nitrate comprises 1 wt% to 8 wt% of the total formulation, more preferably 3 wt% to 7 wt%, and most preferably about 5 wt%.

7. The single-phase non-aqueous dentifrice composition according to any one of the preceding claims, wherein the stannous fluoride comprises 0.1 wt% to 1 wt% of the formulation, preferably 0.3 wt% to 0.7 wt%, and most preferably 0.4 wt% to 0.6 wt%.

8. The single-phase non-aqueous dentifrice composition according to any one of the preceding claims, wherein the composition further comprises at least one surfactant, and wherein the at least one surfactant is present in an amount of 0.5 wt% to 5 wt%, preferably 1.0 wt% to 4.0 wt%, and most preferably 2.0 wt% to 3.0 wt%.

9. The single-phase non-aqueous dentifrice composition according to claim 8, wherein the at least one surfactant comprises an anionic surfactant.

10. The single-phase non-aqueous dentifrice composition according to claim 8 or 9, wherein the one or more surfactants is sodium lauryl sulfate (SLS).

11. The single-phase non-aqueous dentifrice composition according to any one of the preceding claims, wherein the composition further comprises a thickening gum in an amount between 0.05 wt% and 5 wt% of the composition, more preferably between 0.075 wt% and 1 wt%, and most preferably between 0.1 wt% and 0.5 wt%.

12. The single-phase non-aqueous dentifrice composition according to claim 11, wherein the thickening gum comprises carrageenan.

13. The single-phase non-aqueous dentifrice composition according to any one of the preceding claims, wherein the composition further comprises one or more additional silica, and the total silica content is between 1% by weight and 20% by weight, preferably between 5% by weight and 15% by weight.

14. The single-phase non-aqueous dentifrice composition according to any one of the preceding claims, wherein the composition further comprises one or more additional fluoride sources.

15. The dentifrice composition according to any one of the preceding claims, wherein the composition further comprises one or more additional ingredients selected from the group consisting of flavoring agents, sweetening agents, coloring agents, whitening agents, pH regulators, rheology modifiers, antimicrobial agents, preservatives, and mixtures thereof.

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