CZ20031836A3 - Zinc-containing oral composition exhibiting reduced astringent activity and process of its preparation - Google Patents

Abstract

A stable, zinc containing aqueous oral composition having low astringency, the composition containing a mixture of a zinc salt, an anionic polycarboxylate polymer and a pyrophosphate salt whereby less astringency is experienced by the user of the composition.

Description

Oral composition containing zinc with reduced astringent effect and process for its preparation

Technical field

The present invention relates to a dentifrice composition for reducing bad breath odor, and more particularly to a low astringency breath freshening oral hygiene composition for treating a bad breath odor comprising zinc salts and pyrophosphate salts.

BACKGROUND OF THE INVENTION

Halitosis is caused by the rotting activity of the microorganisms on the respective substrate components of the dental plaque, adherents adhering to the mucous membranes and the saliva cell elements to produce volatile sulfur compounds, particularly hydrogen sulfide, methyl mercaptan and traces of methylsulfide.

The incorporation of zinc salts into oral hygiene compositions for the benefit of reducing oral malodor is well known in the art, for example, from U.S. Patent Nos. 4,138,477 and 5,000,944. However, the main disadvantage of zinc salts when used in oral dental hygiene products is their astringent effects, which create an undesirable astringent taste in the mouth.

US 4,138,477 describes oral compositions comprising zinc salts with reduced astringent effect comprising a zinc-polymer complex formed by reacting a zinc salt with an anionic polymer containing carboxylic, sulfonic and / or phosphonic acid residues.

US 5,000,944 discloses an oral composition containing zinc against tartar, which is substantially free of astringent effects and comprises, as a principal agent, a zinc / polyphosphate complex having at least about 50% water solubility; 9 9 9

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Formed by reacting a zinc salt with a potassium or sodium polyphosphate salt, by dissolving the zinc salt in a polyphosphate solution such as pyrophosphate, tripolyphosphate, hexametaphosphate, and combinations thereof.

Although the astringency effects are largely limited, the disadvantage of the zinc / polyphosphate complex is that dentifrices containing zinc and polyphosphate salts tend to be unstable because polycrystalline bodies are formed during storage, and this formation is believed to be due to aggregation zinc-polyphosphate complex crystals. These bodies are visible to the naked eye and exhibit substantial hardness, so that the spontaneous formation of these zinc / polyphosphate crystals is highly undesirable and detrimental to consumer acceptance of the dental product. Therefore, there is a need in the art for means to improve the stability as well as the astringent properties of oral hygiene products such that these products are more acceptable for consumer use.

SUMMARY OF THE INVENTION

The present invention provides a stable aqueous oral hygiene composition for treating bad breath odor exhibiting low astringency effects comprising an orally acceptable carrier comprising a complex formed from a zinc salt, an anionic polycarboxylate polymer and a pyrophosphate salt incorporated into the oral hygiene composition.

As will be shown below, the presence of an anionic zinc / polycarboxylate polymer / pyrophosphate complex in the oral hygiene product results in an unexpectedly stable product with substantially reduced astringent effects exhibiting improved taste properties when used by the consumer.

In the present invention, the zinc ion source used to form the zinc / polycarboxylate polymer complex is rfrfrfrf rf rfrfrfrfrf rf Anionic / pyrophosphate in an oral care composition generally a zinc salt that is fully or partially water soluble, including zinc nitrate, sulfate zinc, zinc citrate, zinc chloride, with zinc citrate being preferred. The zinc salt is present in the oral care composition of the present invention at a concentration of about 1 to about 5% by weight. % and preferably about 1.5 to about 3 wt.

The anionic polycarboxylate polymers used to form the zinc / anionic polycarboxylate polymer / pyrophosphate complex are generally used in the form of their free acids or preferably partially or fully neutralized, water-soluble, alkali metal (e.g., potassium and preferably sodium) salts or ammonium salts. Preferred are 1: 4 and 4: 1 copolymers of maleic anhydride or maleic acid with another polymerizable ethylenically unsaturated monomer, preferably methyl vinyl ether / maleic anhydride with a molecular weight (MW) of about 30,000 to about 1,800,000, most preferably about 30,000 to about 700,000. these copolymers are available from ISP Corporation under the trade name Gantrez, e.g., AN 139 (MW 500 000), AN 119 (MW 250 000); S-97 Pharmaceutical Grade (MW 700,000), AN 269 (MW 1,200,000 to 1,800,000), and AN 179 (MW greater than 1,800,000); wherein the preferred copolymer is S-97 Pharmaceutical Grade (MW 700,000).

An anionic polycarboxylate polymer is used in an amount effective to form a zinc / polymer / pyrophosphate complex in the oral composition. To this end, the anionic polycarboxylate polymer is present in the oral care composition in an amount of from about 0.1% to about 10% by weight, preferably from about 0.2% to about 3.0% by weight.

The pyrophosphate salts used to prepare zinc complexes / anionic polymer / pyrophosphate include dialkali salts.

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9 9 9 9 9 9 9 • 99 · or, tetra pyrophosphate salts such as Na ₂ P 2 O _7, K2P2O7, Na ₂ K ₂ P ₂ O _7, Na ₂ H ₂ P ₂ O ₇ and K ₂ H ₂ P ₂ O ₇ . The pyrophosphate salts are present in the oral composition of the present invention at a concentration of from about 1 to about 5% by weight. % and preferably from about 0.5 to about 3 wt.

To prepare a dental composition of the present invention, the zinc salt, anionic polycarboxylate polymer and pyrophosphate salt are incorporated into an oral care product comprising a carrier comprising water, a humectant, a surfactant and a polishing agent.

The humectant is generally a mixture of humectants such as glycerol, sorbitol and polyethylene glycol having a molecular weight in the range of 200 to 100, but other humectant mixtures and individual humectants may also be used. The humectant content is in the range of about 10% to about 80% by weight, preferably about 30 to about 50% by weight. The water content ranges from about 10 to about 25% by weight.

Inorganic thickeners may be included in the potassium salt composition component and include burnt silicas (SiO ₂ ), such as Cabosil available from Cabot Corporation, and thickening silicas including those available from Crosfield Chemicals designated Sorbosil TC-15 or Sylox 15 from WR Grace.

Organic thickeners from natural and synthetic thickeners may be incorporated in the oral care composition of the present invention, such as carrageenan sodium carboxymethylcellulose, hydroxyethylpropylcellulose, gums. Examples of these (Irish moss), xanthan gum, starch, polyvinylpyrrolidone, hydroxybutylmethylcellulose, hydroxypropylmethylcellulose and hydroxyethylcellulose. Organic thickeners may be present in the compositions of the present invention at a concentration of about 0.25 to about 2% by weight. % and preferably about 0.5 to about 1 wt.

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Surfactants may be included in the oral care composition of the present invention as a foaming agent. The surfactant is preferably anionic in nature, suitable examples of such surfactants include higher alkyl sulfates such as potassium or sodium lauryl sulfate, which is preferred, higher fatty acid monoglyceride monosulfates such as coconut oil monosulfated monoglyceride salt, alkyl aryl sulfonates such as sodium bisodium dodecate. higher fatty sulfoacetates, higher fatty acid esters of 1,2-dihydroxypropanesulfonate, and substantially saturated higher aliphatic acylamides of lower aliphatic aminocarboxylic acids, such as those containing 12 to 16 carbon atoms in the fatty acid residue, alkyl or acyl residue, and the like. amides are N-lauroylsarcosine and salts of Ν-lauroyl-, N-myristoyl- or N-palmitoylsarcosine. The surfactant is generally present in the oral care compositions of the present invention at a concentration of about 0.5 to about 5.0% by weight.

Abrasives may be incorporated into the oral care composition of the present invention. Suitable abrasives are silicas, such as silica. A preferred silica is a precipitated amorphous hydrated silica such as Sorbosil AC-35, sold by Crosfield Chemicals, or Zeodent 115 and Zeodent 165 from the Huber Company. However, other abrasives may also be used, including sodium metaphosphate, potassium metaphosphate, calcium phosphate, calcium phosphate dihydrate, calcium hydrogen phosphate anhydrous, calcium pyrophosphate, magnesium orthophosphate, calcium carbonate, sodium bicarbonate, alumina, silicate, alumina, silicate, alumina, silicate. The abrasive concentration in the oral composition of the present invention will generally be in the range of 5 to about 40 wt%, preferably 10 to 30 wt%.

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Other substances that may be included in the oral care composition of the present invention include pigment, sweetener, flavoring and preservative. In white cream dental preparations, the pigment of choice is titanium dioxide, rutile. Its proportion is usually in the range of 0.5 to 1.25% by weight, preferably 0.75 to 1% by weight. The sweetener content is usually the content of a substitute or synthetic sweetener, its usual proportion being in the range of 0.1 to 1% by weight, preferably 0.3 to 0.5% by weight. The content of the flavoring agent, which is preferably a mixed peppermint / menthol flavoring agent, is usually in the range of 0.5 to 2% by weight, preferably 0.5 to 1.5% by weight. F. D. & C Grade dyes may be used in appropriate amounts to achieve the desired coloration. The content of other ingredients or excipients of the potassium salt-containing dental composition usually does not exceed 10% by weight, often less than 5% by weight, and may be 0%.

To prepare the oral composition of the present invention, the zinc salt is added to a mixture of water, humectants and an anionic polycarboxylate polymer and dispersed in a conventional mixer until the mixture becomes a slurry. The pyrophosphate salt may also be added at this point, preferably pre-dissolved as an aqueous solution. Other water-soluble substances such as fluoride salts and sweeteners such as sodium saccharin may also be added at this point. This mixture can be heated to 37.77 to 43.33 ° C and stirred for 10 to 30 minutes to form a homogeneous gel phase. The mixture was transferred to a vacuum mixer. The abrasive is then added and stirred for 10 to 30 minutes at high speed under vacuum in the range of 5 to 100 mmHg, preferably 5 to 50 mmHg, to form a homogeneous mixture. The surfactant and the flavoring agent are then added to the paste, followed by stirring for an additional 10 to 20 minutes under a vacuum of 5 to 50 mmHg. The resulting product is a stable astringent dental composition with the structure of normal toothpastes or

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4 4 44 44 44 gels, with a pH value ranging from 5 to 8, preferably 6.5 to 7 5, e.g. 7, and a satisfactory taste.

The following exemplary embodiment is intended to further illustrate the present invention, but should not be construed as limiting the present invention in any way. All amounts set forth in this example and the appended claims are by weight.

DETAILED DESCRIPTION OF THE INVENTION

Example 1

An aqueous dental composition was prepared by mixing the ingredients listed in Table 1 below.

Table 1

Substance % wt. deionized water 17.54 zinc citrate trihydrate 2.00 Gantrez S-97 (13% solution) 11.54 PEG 600 3.00 glycerine 11.50 carrageenan 0, 400 sodium carboxymethylcellulose 0, 60 sorbitol (70% solution) 24.60 natriumsacharin 0.300 tetrasodium pyrophosphate 2,0 titanium dioxide 1.00 sodium fluoride 0.32 silica 22.20 NaOH (50% solution) 0, 60 aromatic agent 1.20 sodium lauryl sulfate 1.20 Total 100.00

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No crystalline material formation was observed after storage of the dental product in hermetically sealed plastic tubes for 8 weeks at 4.44 ° C, room temperature, 40.55 ° C and 48.88 ° C.

The astringent properties and palatability of the dental device have been evaluated by the taster, having regard to attributes such as astringency effects and taste acceptability, as compared to a commercial non-astringent antibacterial dental device which did not contain zinc ion and a commercial dental device known % by weight, said compound having astringent effects containing 2 wt. zinc citrate.

The dentist rated the dental device as showing lower astringency effects.

When the dental composition of Example 1 was prepared in which zinc citrate was incorporated into the dental composition together with 1 wt. % tetrasodium pyrophosphate and 7 wt. sodium tripolyphosphate, and an anionic polycarboxylate polymer of Gantrez S-97 was not present in the dental composition, the composition showed low astringent effects, but undesirable crystals were formed in the dental composition for 15 days when stored in plastic tubes at room temperature.

Claims (14)

PATENT CLAIMS A stable, aqueous, low astringent zinc oral composition comprising an orally acceptable carrier comprising a complex formed in a carrier of a zinc salt, an anionic polycarboxylate polymer and a pyrophosphate salt, wherein the user of the composition feels less astringent effects. Composition according to claim 1, characterized in that the zinc salt is zinc citrate. 3. The composition of claim 1 wherein the pyrophosphate salt is tetrasodium pyrophosphate or tetrasodium pyrophosphate. 4. The composition of claim 1, wherein the polycarboxylate polymer of anionic nature is a vinyl ether / maleic anhydride copolymer. The composition of claim 1, wherein the copolymer is present in the composition at a concentration of about 0.1 to about 10% by weight. The composition of claim 4, wherein the zinc salt is present in the composition at a concentration of about 1 to about 5% by weight. The composition of claim 1, wherein the pyrophosphate salt is present in the composition at a concentration of about 0.5 to about 3.0% by weight. 8. A process for the preparation of a stable, aqueous, low astringent zinc oral composition comprising preparing an orally acceptable carrier comprising water and humectants and mixing the zinc salt, anionic polycarboxylate polymer and pyrophosphate salt with the carrier. to form an anionic zinc / polycarboxylate / pyrophosphate complex, wherein the user of the composition feels less astringent effects. The method of claim 8, wherein the zinc salt is zinc citrate. 10. The method of claim 8 wherein the pyrophosphate salt is tetrasodium pyrophosphate or tetrasodium pyrophosphate. 11. The process of claim 8 wherein the polycarboxylate polymer of anionic nature is a vinyl ether / maleic anhydride copolymer. The method of claim 11, wherein the copolymer is present in the composition at a concentration of about 0.1 to about 10% by weight. The method of claim 8, wherein the zinc salt is present in the composition at a concentration of about 1 to about 5% by weight. The method of claim 8, wherein the pyrophosphate salt is present in the composition at a concentration of about 0.5 to about 3.0% by weight.