Dentifrice compositions comprising finely divided alumina

Abstract

The present invention relates to a dentifrice composition comprising a fine ground alumina having a D90 particle size of less than 3 µm as a opacifier in an orally acceptable carrier.

Description

Technical Field

[0001] This invention relates to a dental cleaning composition comprising finely ground alumina and an orally acceptable carrier, wherein the alumina has a D90 particle size of less than 3 µm. The dental cleaning composition comprising finely ground alumina is highly light-shielding. The composition may be titanium dioxide-free. Background Technology

[0002] Oral care compositions, especially dental floss, are used to clean teeth daily. The most common form of dental floss is a paste.

[0003] Pastes are made from a variety of different ingredients, and most commonly they are treated with dyes or pigments to give them an attractive appearance to consumers.

[0004] Titanium dioxide is the most widely used white pigment in toothpaste due to its brightness and very high refractive index (~2.6), which is surpassed by only a handful of other materials. At low levels, it produces a bright white, which is highly prized in many consumer products.

[0005] Although titanium dioxide has long been used in many applications, including food coloring, concerns and debates regarding its potential toxicity to humans led to the European Union banning its use in food applications since February 2022. Currently, at least two US states are also considering banning the material in food.

[0006] Although toothpaste is not designed for consumption, it is used in the mouth. The hope is to find alternative whitening additives that do not contain the potential toxicity provided by titanium dioxide.

[0007] For widespread application across a range of dental cleaning compositions, alternative whitening additives must be non-toxic and non-reactive, and introduce as few other properties as possible into the composition. Summary of the Invention

[0008] In its broadest aspect, the invention includes a dental cleaning composition comprising finely ground alumina with a D90 particle size of less than 3 μm and an orally acceptable carrier.

[0009] In a further embodiment of the dental cleaning composition, the D90 particle size of the finely ground alumina is less than 2 µm.

[0010] In a further embodiment, the bulk density of the finely ground alumina is 800 g / 1000 cm³. 3 Up to 1200 g / 1000 cm 3 between.

[0011] In a further embodiment, the finely ground alumina accounts for 0.05% to 15% by weight.

[0012] In a further embodiment, the finely ground alumina accounts for 0.1% to 2% by weight.

[0013] In a further embodiment, the dental cleaning composition is aqueous or non-aqueous.

[0014] In a further embodiment, the dental cleaning composition comprises an abrasive.

[0015] In a further embodiment, the dental cleaning composition comprises a water-soluble condensed phosphate.

[0016] In a further embodiment, the dental cleaning agent contains at least one surfactant.

[0017] In a further embodiment, the dental cleaning composition further comprises two or more surfactants.

[0018] In a further embodiment, the surfactant comprises 0.1% to 5% by weight of surfactant.

[0019] In a further embodiment, the composition further comprises a desensitizing agent.

[0020] In a further embodiment, the composition further comprises a desensitizing agent, an antibacterial agent, an anti-plaque agent, an anti-tartar agent, an anti-bad breath agent, an anti-inflammatory agent, an antioxidant, an antifungal agent, a wound healing agent, or a mixture of at least two of these.

[0021] In a further embodiment, the composition further comprises a fluoride ion source.

[0022] In a further embodiment, the composition does not contain titanium dioxide.

[0023] In a further embodiment, finely ground alumina has no abrasive effect in the dental cleaning agent composition. Invention Details

[0025] The invention is described in more detail below.

[0026] When reviewing the following description of the invention, the following definitions should be considered.

[0027] As used in this article, the word "comprising" encompasses both "composed of" and "essentially composed of".

[0028] As used herein, the word “include” and its variations are intended to be non-limiting, such that the description of items in the list does not exclude the use of other items in the materials, compositions and methods of the present invention.

[0029] Unless otherwise stated, all percentages used herein are by weight of the total dental cleaning agent composition.

[0030] As used throughout, a range is used as a shorthand to describe each value within the range. Any value within the range can be chosen as the endpoint of the range.

[0031] In this article, "effective amount" refers to the amount of a given reagent or material that is sufficient to provide positive benefits, typically oral health benefits.

[0032] As used herein, when applied to the value of a parameter of a composition, the word “about” indicates that the calculation or measurement of that value allows for some slight inaccuracies that have no substantial effect on the chemical or physical properties of the composition.

[0033] There are many ways to define particle size distribution. Cumulative distribution is particularly common, and the most important way to define it is through percentiles. These percentiles, in each case, represent a certain number of samples that are smaller than their size x.

[0034] Percentiles are indicated by the letter D followed by the % value. Therefore, for the purposes of this invention, a D90 value indicates that 90% of the alumina particles used are smaller than the indicated size.

[0035] Dental cleaning compositions are products intended for oral application for a period of time sufficient to maintain contact with all tooth surfaces and / or oral tissues for oral activity purposes. As used herein, unless otherwise stated, "dental cleaning composition" may refer to a paste or gel formulation.

[0036] Preferably, the dental cleaning composition is a toothpaste composition.

[0037] Alumina (or aluminum oxide (III)) is a compound of aluminum and oxygen, with the chemical formula Al₂O₃. It is the most common of the several types of alumina and is specifically referred to as aluminum oxide. It is commonly known as aluminum oxide, but can also be called aluminum oxide, aluminum sand, or corundum in various forms and applications.

[0038] Alumina is well known for its use in oral care compositions. It is widely used as an abrasive. Alumina added as an abrasive is typically used with a particle size greater than 10 μm.

[0039] Alumina is also known for its light-blocking properties. GB1407787 details oral care compositions containing alumina flakes with an average diameter of less than 20 micrometers and a thickness of less than 3 micrometers as a light-blocking agent. However, this form of alumina flake also exhibits significant abrasive properties.

[0040] Careful control of the abrasive level in toothpaste is crucial to optimize cleaning performance relative to enamel damage. Opacifying ingredients that modify the abrasive properties of toothpaste are undesirable. In fact, alumina is not yet commercially available as an opacifier.

[0041] The applicant has surprisingly discovered that very finely ground alumina particles maintain a strong (or even stronger) light-blocking effect while losing the potentially troublesome grinding properties.

[0042] In particular, alumina powder with a D90 particle size of less than 3 µm has been found to have excellent light-blocking (whitening) properties in dental cleaning agents, especially toothpaste. At this particle size, alumina has been found to have no measurable effect on the abrasive properties of dental cleaning agents.

[0043] Preferably, the alumina may have a D90 particle size of less than 2 μm.

[0044] Preferably, the alumina has a content of 800 g / 1000 cm³. 3 Up to 1200 g / 1000 cm 3 The packing density.

[0045] For decades, aluminum oxide has been known to be used as an abrasive in dental cleaning agents and is therefore considered a safe ingredient.

[0046] However, in the fine-grind form of the present invention, it has been found that alumina does not exhibit significant abrasive properties when added to the dental cleaning agent composition.

[0047] The finely ground alumina of the present invention can be added to dental cleaning compositions in any desired amount.

[0048] Preferably, 0.05% to 15% by weight of finely ground alumina is added to the dental cleaning agent composition to provide optimal whitening (shining) properties.

[0049] In a further embodiment, 0.1% to 2% by weight and 0.2% to 0.8% by weight of finely ground alumina are added to the dental cleaning composition.

[0050] Adding finely ground alumina to a dental cleaning composition provides it with a strong light-blocking (whitening appearance) effect.

[0051] To obtain a strong white appearance, 1.0% to 2.0% by weight, preferably 1.2% to 1.8% by weight, of finely ground alumina can be added to the dental cleaning composition.

[0052] A commercially viable source of the alumina used in this invention is Ultimate P1800® alumina from Almatis. Ultimate P1800® has a D90 of less than 2 µm and a D50 of less than 0.5 µm. The applicant has found that adding alumina powder with a D90 particle size of less than 3 µm to toothpaste does not have an abrasive effect.

[0053] The finely ground alumina of the present invention has been found to be resistant to a wide range of oral active ingredients, including fluoride sources, antimicrobial agents, and desensitizing agents, without any negative impact on its performance. This makes it extremely versatile as a light-shielding agent in dental cleaning agents.

[0054] The dental cleaning composition can then be sold to consumers without adding additional dyes or colorants.

[0055] The dental cleaning composition of the present invention may also be used with the addition of additional dyes or colorants as needed.

[0056] The dental cleaning compositions of the present invention can be aqueous or non-aqueous. The water used to prepare commercially suitable compositions should preferably have a low ion content and be free of organic impurities. When present, water typically constitutes about 5% to about 70% by weight of the composition, for example, 10% to 50% by weight. Typically, the water level is at most 40% by weight of the composition, for example, at most 36% by weight, for example, 0.1% to 35% by weight. The amount of water includes added free water plus water introduced along with other materials (e.g., wetting agents or surfactants).

[0057] The dental cleaning compositions of the present invention may further comprise water-soluble condensed phosphates, such as alkali metal pyrophosphates, tripolyphosphates, or higher polyphosphates, particularly water-soluble alkali metal tripolyphosphates. Suitably, the sodium form of such salt is preferred, although potassium or mixed sodium and potassium salts may also be used as preferred embodiments. All physical forms, such as hydrated or dehydrated forms, can be used.

[0058] Most suitable is sodium tripolyphosphate, which is a water-soluble alkali metal tripolyphosphate.

[0059] Suitablely, the water-soluble condensed phosphate (e.g., alkali metal tripolyphosphate) is present in an amount of 1.0% to 20.0% by weight, for example 2.0% to 15.0% by weight, or 1.0% to 10% by weight, or 5.0% to 10.0% by weight of the composition.

[0060] The dental cleaning composition of the present invention may further comprise an alkali metal bicarbonate. The inclusion of such a salt in the dental cleaning composition is advantageous for several reasons, such as providing good plaque removal ability and improving the whitening properties of the dental cleaning agent. Importantly, the bicarbonate provides a clean and fresh feeling in the mouth after brushing and rinsing with water. Suitably, the alkaline bicarbonate is sodium bicarbonate. Suitably, sodium bicarbonate is present in an amount of 20% to 90% by weight of the composition, preferably 60% to 80% by weight, more preferably 65% ​​to 70% by weight, for example, 66% to 68% by weight of the composition.

[0061] The dental cleaning compositions of the present invention may contain one or more active ingredients conventionally used in dental cleaning compositions, such as fluoride sources, desensitizing agents, antibacterial agents, anti-plaque agents, anti-tartar agents, anti-halitosis agents, anti-inflammatory agents, antioxidants, antifungal agents, wound healing agents, or mixtures of at least two of these. Such agents may be included at a level that provides the desired therapeutic effect.

[0062] Examples of desensitizers include tubule blockers or neurosensitizers and mixtures thereof, such as those described in WO02 / 15809 (Block). Examples of desensitizers include strontium salts, such as strontium chloride, strontium acetate, or strontium nitrate, or potassium salts, such as potassium citrate, potassium chloride, potassium bicarbonate, potassium gluconate, and especially potassium nitrate.

[0063] Desensitizing agents (e.g., potassium salts) are typically present in amounts ranging from 2% to 8% by weight of the composition, such as 5% by weight of the composition.

[0064] In another embodiment, the desensitizing agent comprises calcium arginine carbonate. Suitably, the arginine carbonate is present in an amount of 0.5% to 30% by weight of the composition, for example, 1% to 10% by weight of the composition, or 1% to 10% by weight of the composition, for example, 2% to 8% by weight of the composition.

[0065] In one embodiment, the desensitizing agent comprises a bioactive glass. Suitably, the bioactive glass consists of 45 wt% silica, 24.5 wt% sodium oxide, 6 wt% phosphorus oxide, and 24.5 wt% calcium oxide. Such a bioactive glass is commercially available under the trade name NOVAMIN, also known as 45S5 BIOGLASS.

[0066] Suitable, the bioactive glass is present in an amount of 1% to 20% by weight of the composition, for example, 1% to 15% by weight of the composition, or 1% to 10% by weight of the composition, or 2% to 8% by weight of the composition.

[0067] In one embodiment, the desensitizing agent comprises a stannous salt, such as stannous chloride or stannous fluoride. Stannous salts form insoluble metal salts through hydrolysis and oxidation reactions, which precipitate in dentinal tubules and on the dentinal surface to provide effective relief from dentin hypersensitivity. Stannous salts also offer benefits against tooth erosion, caries, and plaque / gingivitis.

[0068] In a further embodiment, the desensitizing agent comprises silica, colloidal silica, nano zinc oxide, submicron alumina, and submicron polymer beads in the form of fine particles, having an average particle size in the range of 1 nm to 5 µm.

[0069] Suitable fluoride ion sources for use in 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 fluoride, in an amount providing 25 ppm to 3500 ppm of fluoride ions, preferably 100 ppm to 1500 ppm. A typical fluoride ion source is sodium fluoride; for example, the composition may contain 0.1 wt% to 0.5 wt% sodium fluoride, such as 0.204 wt% (equivalent to 923 ppm of fluoride ions), 0.2542 wt% (equivalent to 1150 ppm of fluoride ions), or 0.315 wt% (equivalent to 1426 ppm of fluoride ions).

[0070] These fluoride ions help promote tooth remineralization and increase the acid resistance of tooth hard tissues to combat tooth decay, tooth erosion (i.e., acid abrasion), and / or tooth wear.

[0071] The compositions of the present invention will contain additional formulations, such as surfactants, wetting agents, non-abrasive (thickening) silica, flavoring agents, sweeteners, opacifiers or colorants, preservatives and water, selected from those conventionally used in the field of oral hygiene compositions for such purposes.

[0072] Suitable surfactants for use in this invention include anionic surfactants, such as C 10-18 Sodium alkyl sulfates, such as sodium lauryl sulfate. Sodium lauryl sulfate is generally considered anionic and strongly charged, and is useful if a high level of foaming is needed when brushing teeth.

[0073] Besides anionic surfactants, amphoteric surfactants, cationic surfactants, and nonionic or low-ionic surfactants can also be used to enhance foaming properties. When anionic and amphoteric surfactants are used together, an optimized foaming system is obtained, which provides improved taste and good cleaning. Examples of amphoteric surfactants include long-chain alkyl groups (e.g., C464-C ... 10 -C 18Alkyl betaines, such as those marketed by Albright & Wilson under the trade name "Empigen BB", and long-chain alkyl amide alkyl betaines, such as cocamidopropyl betaine.

[0074] A particularly preferred example of anionic / amphoteric surfactant combination used in the present invention is sodium dodecyl sulfate / cocamidopropyl betaine.

[0075] Suitablely, the surfactant is present in the range of 0.1% to 15% by weight of the composition, for example, 0.5% to 10% by weight of the composition or 1.0% to 5% by weight of the composition.

[0076] Suitable wetting agents for use in the compositions of the present invention include glycerin, xylitol, sorbitol, propylene glycol or polyethylene glycol, or a mixture of at least two thereof; the wetting agent may be present in an amount of 10% to 80% by weight of the composition, for example 20% to 70% by weight of the composition, or 30% to 60% by weight of the composition.

[0077] The dental cleaning compositions of the present invention are typically formulated in the form of toothpaste, instant powder, tablets, and gels. Preferred compositions of the present invention are toothpaste and gels.

[0078] The dental cleaning agents of the present invention are typically formulated in the form of a paste, which is suitable for containment in and dispensing from laminated tubing or pumps as conventionally used in the art. Further examples may include bag-in-can or bag-on-valve delivery systems utilizing foaming agents such as pentane or isopentane.

[0079] The present invention is further illustrated by the following embodiments.

[0080] Examples of water-based dental cleaning agents.

[0081] The following toothpaste is prepared by mixing all the ingredients together.

[0082] Element weight% water 35 Sorbitol 27 Silica (abrasive) 13 glycerin 10 Silica (thickener) 9 SLS 2 Thickening agent 1 Flavorings 2.3 Sodium fluoride 0.3 Fine alumina (D90 < 3µm) 0.4

[0083] With the addition of 0.4% by weight of fine alumina, the paste is pale white.

[0084] Examples of non-aqueous dental cleaning agents

[0085] The following non-aqueous pastes were prepared.

[0086] Element weight% glycerin 54.5 PEG 400 20 Dental silica 8.40 Hydrated silica 6.0 STP (Sodium Tripolyphosphate) 5.0 SLS 1.10 betaine 0.40 Flavorings / Sweeteners 2.58 Tin fluoride 0.45 Sodium fluoride 0.07 Fine alumina (D90 < 3 µm) 1.50

[0087] With the addition of 1.50% by weight of fine alumina, the paste achieves a bright white appearance.

[0088] The fine alumina used in both examples is Ultimate P1800, commercially available and sold by Almatis. D90 is less than 2 µm, and D50 is less than 0.5 µm.

Claims

1. A dental cleaning composition comprising finely ground alumina powder and an orally acceptable carrier, wherein the finely ground alumina powder has a D90 particle size of less than 3 µm.

2. The dental cleaning composition according to claim 1, wherein the D90 particle size of the finely ground alumina is less than 2 µm.

3. The dental cleaning composition according to claim 1 or 2, wherein the bulk density of the finely ground alumina is 800 g / 1000 cm³. 3 Up to 1200 g / 1000 cm 3 .

4. The dental cleaning composition according to any one of the preceding claims, wherein the finely ground alumina accounts for 0.1% to 2% by weight of the composition.

5. The dental cleaning composition according to any one of the preceding claims, wherein the dental cleaning composition is a non-aqueous dental cleaning composition.

6. The dental cleaning composition according to any one of claims 1 to 4, wherein the dental cleaning composition is an aqueous dental cleaning composition.

7. The dental cleaning composition according to any one of the preceding claims, wherein the dental cleaning composition further comprises an abrasive.

8. The dental cleaning composition according to any one of the preceding claims, wherein the dental cleaning composition further comprises a water-soluble condensed phosphate.

9. The dental cleaning composition according to any one of the preceding claims, wherein the dental cleaning composition further comprises at least one surfactant.

10. The dental cleaning composition according to any one of the preceding claims, wherein the dental cleaning composition further comprises two or more surfactants.

11. The dental cleaning composition of claim 9 or claim 10, wherein the composition comprises 0.1% to 5% by weight of a surfactant.

12. The dental cleaning composition according to any one of the preceding claims, wherein the composition further comprises a desensitizing agent, an antibacterial agent, an anti-plaque agent, an anti-tartar agent, an anti-malodor agent, an anti-inflammatory agent, an antioxidant, an antifungal agent, a wound healing agent, or a mixture of at least two of these.

13. The dental cleaning composition according to any one of the preceding claims, further comprising a fluoride ion source.

14. The dental cleaning composition according to any one of the preceding claims, wherein the composition is free of titanium dioxide.

15. The dental cleaning composition according to any one of the preceding claims, wherein the finely ground alumina has no abrasive effect on the composition.