CZ221697A3 - Oral composition - Google Patents

Abstract

A dentifrice composition comprising: a) from about 5 % to about 50 % by weight of sodium bicarbonate; b) a soluble fluoride ion source in an amount sufficient to provide from about 10ppm to about 3500ppm of fluoride ion; c) at least about 1.5 % by weight of tetrasodium pyrophosphate, of which some or all of the tetrasodium pyrophosphate is in the form of undissolved anhydrous tetrasodium pyrophosphate particles; and d) from about 50 % to about 94 % dentifrice carrier materials; and wherein further said composition has a soluble pyrophosphate ion content in the range from about 1 to about 100ppm.

Description

Oral composition

Technical field

The present invention relates to oral compositions. In particular, it relates to so-called sodium bicarbonate dentifrice compositions containing pyrophosphate anti-stone agents having improved stability and aesthetic appearance.

BACKGROUND OF THE INVENTION

Tartar or tartar, as it is sometimes called, is a deposit that forms on the tooth surfaces of the loose gum. The supernum stone appears principally on areas close to the mouth of the saliva ducts; eg, on the lingal surfaces of the lower anterior teeth and on the buccal surfaces of the upper first and second molars, and on the distal surfaces of the back molars.

The mature stone contains an inorganic portion, which is mostly calcium phosphate arranged in a hdroxyapatite crystal lattice structure similar to bone, enamel and dentine. Organic fraction is also present and contains peeled epithelial cells, leukocytes, salivary sediment, food _Λ 4-, τ r: 1, -, _{Λ Λ Λ Λ} «4

α. i uliid ^ν j K j ιιιι Μυυι gan i ^ uiu.

As a mature stone develops, it becomes visible to a white or yellowish color if it is not colored or discolored by any external agent, the photo is not desirable from an aesthetic point of view.

Mechanical stone removal periodically by a dentist is a routine procedure performed in the dentist's office. Many chemical and biological agents are also recommended for retarding stone formation or removing stone after formation. Pyrophosphate salts are chemical agents known to have the ability to retard the formation of stone as described, for example, in US Patent 499184, Parran Jr. et al. granted

March 12, 1991, the disclosure of which is incorporated herein by reference in its entirety.

Dental cleansing compositions containing pyrophosphate salts and sodium bicarbonate (aka, baking soda) are also known and have been described, for example, in U.S. Patent 5,805,776, Winston et al., Issued January 19, 1993, the disclosure of which is incorporated herein by reference in its entirety. Obtaining stable dentifrice compositions containing sodium bicarbonate and pyrophosphates effective to inhibit calculus formation is a problem to be solved. The pyrophosphate dissolved in these dentifrice compositions is likely subsequently recrystallized to form tetrasodium pyrophosphate decahydrate crystals. These crystals can grow into large, glass-like particles that are aesthetically unsuitable and also reduce the effectiveness of tartar control.

U.S. Pat. No. 5,180,576 (supra) herein apparently acknowledges this problem and describes its elimination by a manufacturing process using sodium bicarbonate to remove the alkali metal pyrophosphate salt. the amount of dissolved pyrophosphate salt is therefore reported to be relatively low in the final composition, and the remaining pyrophosphate particles are said to have unsalted pyrophosphate decahydrate salted out with sodium hydrogen carbonate, these undissolved pyrophosphate crystals dissolve very quickly in water, but dissolve very quickly in water, . This is then another way to practice the invention described and claimed, for example, in the US patent

Parran, Jr. 4684518 et al. issued August 4, 1987, the entire disclosure of which is incorporated herein by reference,

It is also known from PCT application US94 / 03280 that dentifrice compositions containing sodium pyrophosphate / bicarbonate that are aesthetically acceptable and effective can be prepared by controlling the process conditions to ensure that it is less than about 20% pyrophosphate solubilized at any point of the treated mixture. In practice, the process described in the above-mentioned application still results in the solubilization of about 5% of the total amount of pyrophosphate. In order to minimize the risk of recrystallization of pyrophosphate decahydrate crystals, it would be desirable to further reduce the amount of soluble pyrophosphate.

It is therefore an object of the invention to provide an easily controlled process for preparing a stable dentifrice composition comprising sodium bicarbonate and pyrophosphate salts. It is also an object to provide stable dentifrice compositions comprising sodium bicarbonate particles and tetrasodium pyrophosphate salt of predetermined and / or consistent size. It is another object of the invention to prepare such stable compositions by a method of controlling production conditions such that the amount of pyrophosphate ion dissolved in the composition is less than iuu ppm, preferably less than 10 ρρΰΊ.

These and other objects of the present invention will become more apparent from the detailed description that follows.

All percentages and ratios used herein are by weight and all measurements were made at 25 ° C unless otherwise stated.

SUMMARY OF THE INVENTION

According to a first aspect of the invention there is provided a dentifrice composition comprising

(a) from about 5% to about 50% by weight of sodium bicarbonate;

b) a soluble fluoride ion source in an amount sufficient to provide from about 10 ppm to about 10 ppm

3500 ppm of fluoride ion,

(c) at least about 1,5% by weight of tetrasodium pyrophosphate, some or all of the tetrasodium pyrophosphate being in the form of undissolved tetrasodium pyrophosphate particles; and

d) from about 50% to about 94% of carrier materials for dentifrices; and wherein said composition further has a soluble pyrophosphate ion content of from about 1 to about 100 ppm, preferably from about 1.5 to about 10 ppm, more preferably from about 2 to about 5 ppm.

The present invention also relates to a method for producing the above-mentioned dentifrice composition comprising the steps of:

(a) forming a premix of carrier materials for dentifrices, including one or more of selected from binder / thickening agents, humectants, buffering agents, abrasive polishing materials, surfactants, sweetening agents, flavoring agents, titanium dioxide, and mixtures thereof, wherein said premix it comprises at least one or more binding / thickening agents and one or more buffering agents sufficient to provide a pH in step b) of greater than a pH of about 8;

b) forming a paste by adding water to the premix in an amount sufficient to hydrate the binder / thickening agent;

c) adding sodium bicarbonate to the resulting paste;

d) then adding tetrasodium pyrophosphate, all at once or in portions, to the paste at a temperature of less than about 30 ° C, preferably less than about 25 ° C, and preferably at a pH greater than about pH 8.

Preferably, tetrasodium pyrophosphate is added to the mixture after all the sodium-containing salts present in the composition have been added to the composition. In preferred embodiments, in addition, the binder / thickening agent and buffering agent are added batchwise to the premix such that multiple alternating layers of binder / thickening agent and buffering agent are provided in the final premix, which is valuable to achieve optimal paste rheology during the binder hydration stage.

The present invention relates to a method of making a sodium bicarbonate dentifrice composition comprising a pyrophosphate agent for controlling tartar. The dentifrice compositions produced by this process may be in the form of toothpastes or gels. The term toothpaste as used herein means paste and gel formulations unless otherwise indicated. The present invention also relates to dentifrice compositions of sodium hydrogencarbonate / pyrophosphate for the control of tartar containing particles of anhydrous tetrasodium pyrophosphate.

The present method and compositions comprise some essential components as well as optional components. A detailed description of these components and the conditions of the present method is provided below.

A) Pyrophosphate salts

The pyrophosphate salts used in the present method and compositions must contain tetrasodium pyrophosphate. This material may be in the form of the anhydrous salt or in the form of decahydrate, or any other stable type in solid form in dentifrice compositions. The salt is in the form of its solid particles, which may be in their crystalline and / or amorphous state, with a particle size of the salt preferably small enough to be aesthetically acceptable and readily soluble during use.

While tetrasodium pyrophosphate particles are an essential component of the present process and compositions, it should be recognized that low amounts of other pyrophosphate salts may be included in the process and compositions. Specific salts include tetraalkali metal pyrophosphates other than tetrasodium pyrophosphate, dialkali metal dihydrogen pyrophosphates, trialkali metal monohydrogen pyrophosphates, and mixtures thereof, wherein alkali metals are sodium or potassium (pyrophosphate salts are described in more detail in Kirk & Othmer, Chemical Technology, Kncyclopedia , Vol. 15, Interscience Publishers (1958), incorporated herein by reference in its entirety). These salts are suitable in both their hydrated and non-hydrated forms. Since the salts are typically more soluble than the tetrasodium pyrophosphate salt, their inclusion in the process and compositions of the invention should be limited to avoid the preparation of compositions containing a soluble pyrophosphate ion, and it is preferred to exclude such more soluble salts.

The amount of pyrophosphate salt used in the compositions is any amount that is effective to control tartar and is generally sufficient to provide at least about 1.0%, preferably from about 1.5% to about 10%, more preferably from about 3.0% to about 3.0%. 6%

Hmotnostiγ ' ^{4 by} weight of the compositions. It is accepted that the amount of P2O7 ^"4 is that amount which is able to be provided to the composition (i.e. the theoretical amount at an appropriate pH) and that other pyrophosphate forms (e.g. HP2O7 ^'3) can be present, when establishing a pH of the final product. The amount of tetrasodium pyrophosphate salt used in the present methods and compositions is therefore from about 1.5% to about 15%, and more preferably from about 2% to about 10% by weight of the dentifrice composition.

B) Sodium bicarbonate

Also known as baking soda, sodium bicarbonate is a household product with many different uses including dentifrices and mouthwashes. It is a white powder that is soluble in water and, without stabilization, tends to release carbon dioxide in the aqueous system. The present compositions comprise from about 5% to about 50%, preferably from about 10% to about 30% sodium bicarbonate based on the weight of the composition.

C) Soluble fluoride ion source

A soluble fluoride ion source is also incorporated into the present compositions. A soluble fluoride ion source is used in amounts sufficient to provide from about 10 to about 3500 ppm of fluoride ion. Preferred fluorides are sodium fluoride, stannous fluoride, indium fluoride and sodium monofluorophosphate. Norris et al., U.S. Pat

No. 29461735, issued July 26, 1960; and Widder et al., U.S. Patent No. 3,778,154, issued July 18, 1972, disclose these 1 other salts.

Both patents are incorporated herein by reference in their entirety.

D) Carrier materials for dentifrices

In preparing the present toothpaste compositions, it is desirable to add one or more carrier materials for dentifrice compositions to the composition. As used herein, carrier materials for dentifrices are any material safe and effective for use in toothpaste compositions prepared in accordance with the present invention. Such materials are well known in the art and can be readily selected by those skilled in the art based on their physical and aesthetic properties required for the dentifrice compositions being prepared. Carrier materials for dentifrice compositions typically comprise from about 50% to about 94%, preferably from about 60% to about 80% by weight of the present compositions.

The present compositions typically comprise a binder / thickening material to provide the desired consistency. Preferred binder / thickening agents are carboxylic acid polymers, carrageenan, hydroxyethyl cellulose and water-soluble salts of cellulose ethers such as sodium carboxymethyl cellulose and sodium carboxymethyl hydroxyethyl cellulose. Natural gums such as gum arabic, zanthan gum, gum arabic, and gum tragacanth may also be used. Colloidal magnesium aluminum silicate or finely divided silicon dioxide can be used as part of the sizing agent to further improve texture. Thickening agents may be used in an amount of from about 0.2% to about 5.0% by weight of the total composition.

It is also desirable to include humectant material in the toothpaste to prevent it from hardening after exposure to air. Certain humectants may also impart desirable sweetness or taste to the toothpaste compositions. Suitable humectants include glycerin sorbitol or edible polyhydric alcohols and mixtures thereof, in an amount of about 15% to about 70% by weight of the composition.

Titanium dioxide may also be included in the present compositions. Titanium dioxide is a white powder which is added to the compositions as a pigment. Titanium dioxide generally constitutes from about 0.25% to about 1% by weight of the composition.

Water is also present in the compositions of this process. The water used in the preparation of commercially suitable toothpastes should preferably be deionized and free of organic impurities. Water generally constitutes from about 12% to about 45%, preferably from about 15% to about 35%, more preferably from about 20% to about 30% by weight of the composition. These amounts of water include free water that is added plus water that is introduced with other materials such as sorbol.

The pH of the present compositions is adjusted using buffering agents. Buffering agents, as used herein, refer to agents that can be used to raise the pH of the compositions in the range above about pK 8 as preferred for the addition of sodium bicarbonate and tetrasodium pyrophosphate. Such agents include trisodium phosphate, sodium hydroxide, and sodium carbonate. Sodium carbonate in an amount of from about 0.5% to about 2% by weight of the composition is preferred.

An abrasive polishing material may also be included. The abrasive polishing material for use in the present invention may be any material that does not excessively abrade dentin. Such materials include, for example, silicas including gels and precipitates, dicalcium orthophosphate dihydrate, calcium pyrophosphate, tricalcium phosphate, calcium polymetaphosphate, insoluble sodium polymetaphosphate, hydrated alumina, and resin abrasive materials such as the particulate condensation products of urea and other particulate condensation products. -em et al. in U.S. Patent 3070510, Dec. 25, 1962, which is incorporated herein by reference. Mixtures of abrasives may also be used.

Silica-based dental abrasives of various types are preferred for their excellent contribution to excellent tooth cleaning and polishing performance without unduly abrading tooth enamel or dentine. The silica abrasive polishing materials useful herein, as well as other abrasives, generally have an average particle size ranging between about 0.1 and 30 microns, preferably 5 and 15 microns. The silica-based abrasives may be precipitated silica or silica gels, such as the silica xerogels described by Pader et al., U.S. Pat. No. 3,582,30, issued Mar. 2, 1970, and DiGiulius, U.S. Pat.

June 21, 1975; both are incorporated herein by reference. Preferred are silica xerogels available under the tradename Syloid from the W. K. Orace Company, Davison Chemical Division. Preferred silica-based precipitated materials include those available from JMHuber Corporation under the trade name Zeodent, especially silica bearing the name Zeodent 119. These silica-based abrasives are described in U.S. Patent 4,340,583, June 29, 1982, incorporated herein by reference. as a reference.

The abrasive is preferably present in an amount of from about 6% to 70%

More preferably from about 15% to about 25% by weight.

The toothpaste compositions may also contain surfactants. Suitable surfactants are those that are sufficiently stable and foam over a wide pH range, including non-soap anionic, nonionic, cationic, zwitterionic and amphoteric organic synthetic detergents. Many of these suitable agents are described by Giesk et al in U.S. Patent 405,1234, Sep. 27, 1977, incorporated herein by reference. Sodium alkyl sulfate and polyethylene glycol in an amount of from about 4% to about 3% by weight of the composition are preferred for use herein.

Flavoring agents may also be added to the present compositions. Suitable flavoring agents include oil of wintergreen, peppermint oil, spearmint oil, sapphire oil and clover oil. Sweetening agents that may be used include aspartame, acesulfame, saccharin, dextrosis, levuloza, and sodium cyclamate. Flavoring and sweetening agents are generally used in the toothpaste in amounts of from about 0.005% to about 2% by weight of the composition.

The compositions of the present invention may also optionally contain pharmaceutical agents (e.g., triclosan) and other stone control agents. Optional stone control agents include such known materials as synthetic anionic polymers (including polyacrylates and copolymers of maleic anhydride or acid and methyl vinyl ether (e.g., Gantrez), as described, for example, in U.S. Patent 4627977 to Gaffar et al. as well as e.g. poly (aminopropanesulfonic acid (AMPS)), polyphosphates (e.g.

tripolyphosphate, hexametaphosphate), diphosphonates (eg HHDP; AHP), polypeptides (such as polyaspartic acid and polyglutamic acid) and mixtures thereof i.

Toothpaste compositions are prepared by mixing together the ingredients described above according to the production method. The method comprises the steps of:

(a) forming a premix of carrier materials for dentifrices comprising one or more materials selected from binding / thickening agents, humectants, buffering agents, abrasive polishing materials, surfactants, sweetening agents, flavoring agents, titanium dioxide and mixtures thereof, said premix comprising at least one or more binder / thickening agents and one or more buffering agents sufficient to provide a pH in step b) of greater than about pH 8;

b) forming a paste by adding water to the premix in an amount sufficient to hydrate the binder / thickening agent;

c) adding bicarbonate to the resulting paste;

d) then adding tetrasodium pyrophosphate, all at once or in portions, to the paste at a temperature of less than about 30 ° C, preferably less than about 25 ° C, and at a pH greater than about pH 8.

Preferably, the amount of pyrophosphate dissolved in the mixture in the methods and compositions of the present invention ranges from about 1 to about 100 ppm, preferably from about 1.5 to about 10 ppm, more preferably from about 2 to about 5 ppm, measured as pyrophosphate ion. A method for measuring pyrophosphate dissolved in a mixture and composition is described and exemplified below. The following examples describe and demonstrate embodiments within the scope of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

Below are examples of toothpaste pastes and gels,

having pyrophosphate content ion about 3.3%. S1 ožka paste gel sodium bicarbonate 20.000 20.000 water 19.773 19.773 silica 15.000 15.000 g1ycer i n 15.000 15.000 Sorbitol (70%) 14.061 14.111 tetrasodium pyrophosphate 5.045 5.045 sodium alkyl sulfate (28%) 4.000 4.000 PPG '6 3.000 3.000 sodium carbonate 1 .250 1 .250 flavor 1.000 1.000 carboxymethyl cellulose 0,800 0,800 saccharin sodium 0.400 0.400 the oxide of those 0.350 0,000 sodium fluoride 0.321 0.321 FD & C Blue # 1 0.000 0.300

The paste compositions are prepared (sorbitol, glycerin, PEG-6) and the particulate mixture is dried as follows. To the ambient temperature humectants is added sodium flour, sodium hydroxide, sodium carboxymethylcellulose and titanium dioxide, sodium carbonate and sodium carboxymethylcellulose (CMC) each added to the particulate mixture twice to give a so-called layered carbonate, CMC, carbonate, CMC. particulate mixture. To this liquid premix, water is then added in an amount sufficient to hydrate the binder, followed by silica.

To this mixture is added sodium bicarbonate, then tetrasodium pyrophosphate, in solid form. Addition of flavor and sodium alkyl sulfate solution yields the final paste product.

The amount of soluble pyrophosphate in these compositions is measured as follows.

3.00 g + 0.001 g of toothpaste are weighed into 50 ml polypropylene centrifuge tubes; deionized water (9.0 mL) and six glass beads were added. Seal and mix vigorously for exactly 2 minutes on a vortex mixer. The contents were transferred to 25 ml centrifuge tubes, capped and rotated at 15000 rpm ^"1 at 10 ° C for 15 minutes. Pipette 1.0 ml of the clear supernatant into a 100 ml volumetric flask and dilute to this volume with deionized water and mix well. Dilute 10 ml of this solution with deionized water and mix well. Ion chromtaography is analyzed,

Claims (9)

PATENT O V É Claims What is claimed is: 1. A dentifrice composition comprising (a) from about 5% to about 50% by weight of sodium bicarbonate; b) a soluble fluoride ion source in an amount sufficient to provide from about 10 ppm to about 10 ppm 3500 ppm of fluoride ion, (c) at least about 1,5% by weight of tetrasodium pyrophosphate, some or all of the tetrasodium pyrophosphate being in the form of undissolved tetrasodium pyrophosphate particles; and d) from about 50% to about 94% of carrier materials for dentifrices; and wherein said composition further has a soluble pyrophosphate ion content in the range of about 1 to about 100 ppm A dentifrice composition according to claim 1, wherein the carrier materials for dentifrice formulations comprise one or more materials selected from binder / thickening agents, humectants, buffering agents, abrasive polishing materials, surfactants, sweetening agents, flavoring agents. , titanium dioxide, and mixtures thereof. The dentifrice composition of claim 2 wherein the buffering agent is selected from trisodium phosphate, sodium hydroxide, sodium carbonate, and mixtures thereof. A dentifrice composition according to any one of claims 1 to 4 3 comprising from about 1.5% to about 15% tetrasodium pyrophosphate. A dentifrice composition according to any one of claims 1 to 5 4 wherein said composition has a soluble pyrophosphate ion content in the range of about 1.5 to 10 ppm. A method for producing a dentifrice composition according to any one of claims 1 to 5, comprising the steps of: (a) forming a premix of carrier materials for dentifrice compositions comprising one or more materials selected from binding / thickening agents, humectants, buffering agents, abrasive polishing materials, surfactants, sweetening agents, flavoring agents, titanium dioxide and mixtures thereof, said premix comprising at least one or more binder / thickening agents and one or more buffering agents sufficient to provide a pH in step b) of greater than about pH 8; b) forming a paste by adding water to the premix in an amount sufficient to hydrate the binder / thickening agent; c) adding bicarbonate to the resulting paste; d) then adding tetrasodium pyrophosphate, all at once or in portions, to the paste at a temperature of less than about 30 ° C, preferably less than about 25 ° C, and at a pH greater than about pH 8. 7. The process of claim 6 wherein the tetrasodium pyrophosphate is added to the mixture after the other sodium-containing salts present in the composition have been added thereto. 8. The method of claim 6 or 7, wherein the buffering agent comprises sodium carbonate. A method according to any one of claims 6 to 8, characterized in that the binder / thickening agent and the buffering agent are added batchwise to the premix so that a plurality of alternating forms are formed in the final premix. binder / thickening agent and buffering agent layers.