MXPA00010503A - Dual component dentifrice composition for fluoridating teeth - Google Patents

Abstract

A method is disclosed for enhancing fluoride availability using an acidulated two component dentifrice system in which the first component contains sodium fluoride and a silica abrasive in an alkaline environment and the second component contains an acid, a phosphate ion source, and a silica abrasive.

Description

DENTÍFRICA COMPOSITION OF DUAL COMPONENT TO FLUORINE TEETH Background of the Invention 1. Field of the Invention This invention is directed to a dentifrice composition containing acidified fluoride compounds effective as anti-caries agents and more particularly to a dual-component dentifrice composition of acidified phosphatide fluoride to fluoridate the teeth. 2. Previous Art It has been known for a long time to include compounds containing fluoride in dentifrices, anticaries agents, and it has been established that these compounds are effective in reducing the incidence of dental caries. The fluoride compounds, which are considered to be the most effective, are sodium fluoride, sodium monofluorophosphate, and stannous fluoride. The fluoride compounds are effective mainly due to the fluoride ions which improve the acid resistance of both the enamel and accelerate the re-ineralization (for example the recalcification) of decaying teeth in their initial phase when decalcification has proceeded only slightly. The effect of improving the acid resistance of enamel is believed to be due to the fact that fluoride ions are incorporated into a hydroxyapatite crystal lattice, which is the main constituent of enamel or, in other words, the fluoride ions partially fluorinatan hydroxyapatite simultaneously repair network irregularities.

The effectiveness of the fluoride treatment to provide the acid resistance of the enamel will depend on the amount of fluoride ion which is available to be deposited on the enamel that is being treated. Also, using phosphate-buffered NaF, the incorporation of fluoride as CaF2 in dental enamel is facilitated at lower pH levels which increases the solubility of enamel. Prencipe and others in the work "Química de Colloide y Superficie", 4th. Chemical Congress of America, New York, (August 25-30, 1991). It is therefore desirable to formulate an acidulated phosphate fluoride toothpaste to improve the deposition of fluoride on dental enamel and take it into dental enamel.

Acidulated phosphate fluoride is described in U.S. Patent Nos. 4,080,440 and 5,603,992 as delivered in a dual component dentifrice composed of a first acrylic component separately housed containing a fluoride salt such as NaF, which are a second component containing ionic calcium ion housed separately forms the two-component dentifrice for remineralization of the teeth. Even though these two separately hosted component formulas avoid any reactions between the ingredients within the first and second component, a reaction occurs within the prime component between the acid, sodium fluoride and silica abrasive reducing the bioavailability of the fluoride ion . Even when the amorphous silica generally used as an abrasive ingredient in the toothpaste is one of the most chemically available inert abrasives, the negatively charged oxygen atoms of the silica are protonated in the acidic environment, and the resulting hydroxyl (OH) moieties hydrogen bind to available ions released from sodium fluoride. This fluoride-hydroxyl bonding occurs in the acidic phosphate silica abrasive systems described in the prior art in the 4,080,440 and 5,603,992 patents, whereby the availability of the fluoride ions present in the toothpaste to fluoridate the enamel with application thereto It is significantly reduced. The magnitude of this reduction in available fluoride demonstrated hereafter.

Therefore, there is a clear need to formulate a stable acidulated phosphate fluoride dentifrice having the maximum deludable fluoride.

SYNTHESIS OF THE INVENTION According to the present invention, it provides a method for the fluoridation of enamel tooth using a multi-component dentifrice composed of semi-solid aqueous components housed separately.; The first component contains sodium fluoride as a source of fluoride ions, in an orally acceptable vehicle having a pH of at least about 7.5 and, the second component contains both a source of phosphate and acid ions. to provide a pH from about 2.5 to about 5.0 in an orally acceptable vehicle; Each component contains a siliceous abrasive, so that with the mixing of the components, a mixture that has a pH of from about 4. to about 6.0 is formed, so that with the application of it mixes the teeth, it increases the availability of fluoride ions.

There has been no recognition in the prior art of the significant loss of fluoride availability during extended storage periods, resulting from the interaction of generally inert silica abrasives, with sodium fluoride, when NaF is present, the source fluoride in dentifrices that have an acidic environment. In accordance with the present invention, as will be further demonstrated herein, the increased fluoride availability resulting from separating the acid and fluoride in the separate dentifrice components, each containing an abrasive d silica is unexpected and significant.

Description of Preferred Additions In use, the components of the component toothpaste of the present invention comprises a first component of toothpaste containing silica abrasive sodium fluoride and a second component of toothpaste containing silica and acid abrasive; these two components are preferably combined in approximately equal proportions by weight, so that about one-third of the concentration of any particular ingredient within any component will be present when the components are combined and applied to the teeth, such as by brushing. Both components are formulated to provide apparent physical characteristics so that the two components are derived simultaneously in the desired predetermined amounts and before extrusion from a pump device or multi-compartment tube.

Toothpaste Vehicle for Both Components In the preparation of the individual dentifrice components of the present invention, the respective sodium acid or fluoride is incorporated within the dentifrice vehicle suitable for use in the oral cavity, which contains humectant water, surfactant and a polishing or abrasive agent. The humectant is generally a mixture of humectant such as glycerol, sorbitol and polyethylene glycol of a molecular weight in the range of 200-1000, but other mixtures of humectants and ionic humectants may be employed. The humectant content within each of the two components is in the range of from about 20% to about 50% by weight, preferably within about 30 to about 45% by weight. The water content is from about 20% to about 45%, and preferably from about 30% to about 42% by weight.

Surfactants or surfactants can be incorporated into the vehicle of the individual components of the present invention, as an ingredient to aid in the total dispersion of the dentifrice through the oral cavity when applied to it, as well as to improve cosmetic acceptance of the toothpaste and the foaming properties. Anionic surfactants are preferred in the first component containing sodium fluoride, nonionic surfactants are preferred in the second acid-containing component.

Examples of the anionic surfactants suitable for use in the first component of the present invention include water soluble salts of the higher alkyl sulfates or sulfoacetate, such as sodium lauryl sulfate, lauryl sodium sulfoacetate, sulfoacetic acid lauryl sodium, or other suitable alkyl sulfates sulphoacetates having from 8 to 18 carbon atoms in the alkyl group; water-soluble salts of onoglycerides sulfonated from higher fatty acids, such as monoglyceryl sodium coconut sulfonate or other suitable sulfonated monoglyceride of fatty acid of 10 to 18 carbon atoms; the sodium lauryl phosphate salts of higher fatty acid amides, for example acids of 12 to 16 carbon atoms, such as lower aliphatic amino acids, for example, taurine or sarcosine, or another acidic amino of 2 to 6 carbon atoms, as N-methyl-N palmitoyl-sodium tauride, N-lauroyl-, N-myristoyl and N-palmotoyl sarcosinates; water-soluble salts of the esters of such fatty acids with isethionic acid or with monosulfat glycerol, such as the sodium salt of the monoglyceride sulfonatad of hydrogenated coconut oil fatty acids; water-soluble salts of olefin sulfonates, for example d-alkene sulfonates or hydroxyalkene sulfonates or mixtures thereof having 12 to 16 carbon atoms in the carbon chain of the molecule, and water-soluble soaps of higher fatty acids such as those of 12 to 18 carbon atoms, for example, coconut fatty acids.

Examples of the nonionic surfactants suitable for use in the second component of the present invention include the condensates of sorbitan esters of fatty acids with ethylene oxide (polysorbate) such as sorbitan monooleate with from about 20 to about 100%. 60 moles of ethylene oxide. A particularly preferred polysorbate is polysorbate 20, polyoxyethylene 20 sorbitan monolaurate sold by ICI Newcastle, Delaware 19720.

Suitable additional nonionic surfactants useful in the second component of the present invention are the condensation products of an alpha-olefin oxide containing from 10 to 20 carbon atoms, a polyhydric alcohol containing from 2 to 10 carbon atoms and from 2 to 6 hydroxyl groups, and either ethylene oxide a mixture of ethylene oxide and propylene oxide. The resulting surfactants are polymers which have a molecular weight ranging from about 400 to about 1600, containing from about 40% to about 80% ethylene oxide, by weight, and having a proportion of mol of alpha-olefin oxide to polyhydric alcohol in the range of from about 1: 1 to about 1: 3, respectively. Other useful nonionic surfactants of the present invention include condensates of sorbitan fatty acid esters with polyethylene glycol such as sorbitan diisostearate condensing with polyethylene glycol.

The surfactant may be present in one or both of the components of the compositions of the present invention, at a concentration of about 0.1 to about . 0% by weight, preferably around 0.2 to about 1.5% by weight of a particular component.

The siliceous abrasive materials useful in the practice of the invention include the preferred silicas which have an average particle size of up to about 20 microns; including hydrated silica; including a precipitated amorphous hydrated silica, such as Zeodent 115, marketed by J.M. Huber Chemical Division, Havre d Grace, Maryland 21078, or Sylodent 783 marketed by Grac Davidson, Baltimore, Maryland 21203.

The silica abrasive is present in each of the two dentifrice components of the present invention at a concentration of from about 5 to about 30% by weight and preferably, from about 5 to about 20% by weight of the respective component.

Component Containing Fluoride Source The first component of the dentifrice composition of the present invention contains sodium fluoride, as the source of fluoride ions. Sodium fluoride is incorporated in the first component at a concentration d about 0.1 to about 3.0% by weight, and preferably at a concentration of 2.0 to about 2.5% by weight. At this preferred concentration, about 4,500 parts per milliliter over 5,600 parts per million, the fluoride ion will be available in the solution, when the first combined second components of the dentifrice composition are blended applied to the teeth.

It is also critical to the practice of the present invention that the first component has been maintained at a pH of at least about 7.5 and preferably at a pH of at least about 8.0. Applicants have discovered that NaF is stable in the presence of a siliceous abrasive in only a neutral or basic pH environment. A buffering agent such as sodium hydroxide and sodium bicarbonate or sodium phosphate can be used to adjust the pH of the dentifrice component containing fluoride ion to the desired basic levels, if necessary.

Component Containing Acid The second component of the dentifrice composition of the present invention which is physically kept separate from the first component until mixed before use, contains an acid or mixture of acids to acidify the dentifrice when the two components are mixed before use. L acidic compounds which may be present in the second component include both mineral and organic acids, such as sulfuric acid, hydrochloric acid, malic acid, alginic acid, succinic acid, lactic acid, bitartaric acid, potassium bitartrate, acid citrate, phosphoric acid, and sodium acid phosphate. . Acidic phosphates are preferred, including phosphoric acid or the phosphoric acid salt containing the P04 radical, such as the acids or the acid salts thereof, such as the sodium monobasic phosphat, not only provides the necessary acidity; It also provides phosphate ions to inhibit any demineralization of dental enamel that may occur with the application of two-component acidulous dentifrice to dienes. In addition, the combination of an acid, such as phosphoric acid and an acid salt, such as monobasic sodium phosphate, provides increased buffering to achieve the desired pH with the mixing of the components of the toothpaste. The preferred acid, phosphoric acid It is commercially available as a liquid at a concentration of 85% and sodium monobasic phosphate, due commercially available with a monohydrate powder.

The acid is incorporated in the second component of the dentifrice composition of the present invention in a total concentration of about 0.7% to about 4% by weight and preferably from about 2.0 to about 3. by weight by weight; the amount being sufficient to obtain pH of from about 2.5 to about 5.0 and preferably from about 3.5 to about 4.5.

The concentration of the phosphate ions of the second component of the present invention is less than about 0.05 M, with a concentration of less than about 0.2 M preferred.

Other Ingredients Common to Both Components Organic and inorganic thickeners may be included in both of the components of the dentifrice of the present invention. Organic thickeners such as synthetic and natural gums and colloids can also be incorporated in the present invention. Examples of organic thickeners include carrageenan (Irish moss) xanthan gum and sodium carboxymethylcellulose, starch, polyvinylpyrrolidone, hydroxyethylpropylcellulose, hydroxybutylmethylcellulose, hydroxypropylmethylcellulose, and hydroxyethylcellulose. Inorganic thickeners include amorphous silica compounds which function as thickeners, such as the colloidal silica compounds available under the trademarks such as Cab-o-si fumed silica manufactured by Cabot Corporation and distributed by Lenape Chemica Bound Brook, New Jersey, Zeodent 165 of JM Huber Chemical Division, Havre de Grace, Maryland 21078 and Sylox 15 by Grac Davidson of Baltimore, Maryland 21203. A combination of inorganic and organic thickeners are preferred and may be present in both components of the present toothpaste and proportions of about 0.5 to about of 15% by weight preferably from about 0.8 to about 6% in each of the two components of toothpaste.

A marbled toothpaste product can be obtained using the multicomponent toothpaste of the present invention, wherein the dyes of the contrasting colors are incorporated in each of the components of the toothpaste to be assorted; the dyes being non-toxic when used in the suggested amounts. The colorants used in the practice of the present invention include both dye pigments.

Pigments used in the practice of the present invention include water-soluble norganic inorganic pigments such as titanium dioxide (Ti02) and chromium oxide greens, ultramarine and pink blues and ferric oxides. Dyes include insoluble dye lacquers in acetic acid prepared by spreading the aluminum or calcium salts of the FD &C dyes on alumina such as FD &C green lacquer, FD &C blue lacquer 2, FD &C lacquer R &D # 20 &lacquer FD &C yellow # 15. The concentration of the dye pigment in the dentifrice composition varies in an amount from about 0.005% to about 2% by weight of the respective component.

Other ingredients which can be incorporated into one or both of the components of the present invention include the antibacterial agents, the active anticalculus, the sweetener, the taste and the preservatives such as sodium benzoate. Preferred antibacterial agents are non-cationic antibacterial agents based on phenolic and bisphenolic compounds, halogenated diphenyl ethers, such as triclosan, benzoate esters and carbanalides. Cationic antibacterial agents which are also preferred include quaternary ammonium salts such as digluconate d chlorhexidine; fluids in the second component containing acid of the present invention. Such antibacterial agents may be present in amounts of about 0.03 about 1% by weight of the particular component.

Anti-jar assets such as sodium tripolyphosphate, tetrapotassium or tetrasodium phosphates, or mixtures d thereof may be present in concentrations of from about 0.5 to about 8% by weight of the particular component in which such active agents are stable. The sweetener content will normally be that of a synthetic artificial sweetener and the normal proportion thereof will be present in the range of 0.1 to 1% by weight of the respective component preferably 0.2 to 0.5% by weight of the respective component The flavor content which it is preferably a fruit or mint flavor / mixed menthol, usually in the range 0.5 to 2% by weight of the respective component, preferably 0.5 to 1% by weight of the respective component. The components obtained from the other auxiliary components normally will not exceed 10% by weight, will often be less than 5 by weight and can be as low as 0%.

When the non-cationic antibacterial agents included in any of the dentifrice components, it also preferably includes from about 0.5 to about 5% of an antibacterial enhancing agent (AEA) which increases the delivery and retention of the non-cationic antibacterial agent and the retention of the same on the oral surfaces. The antibacterial enhancement agents useful in the present invention are described in U.S. Patent Nos. 5,188,821 and 5,192,531; and include the synthetic anionic polymeric polycarboxylates, in the form of copolymers of 1: 4 to 4: 1 of maleic anhydride or of acid with a polymerizable ethylenically unsaturated monomer, preferably a maleic anhydride of vinyl methyl ether having a molecular weight (M. .) from about 30,000 to about 1,000,000, more preferably from about 30,000 to about 800,000. These available copolymers for example with co or Gantrez, for example, AN 139 (molecular weight 500,000) AN 11 (molecular weight 250,000) and preferably S-97 Clas Pharmaceutical (molecular weight 700,000) available from IS Technologies, Inc., of Bound Brook, New Jersey 08805.

Preparation of the toothpaste To prepare any of the dentifrice components of the present invention, generally humectants, for example, glycerin, propylene glycol, polyethylene glycol ingredients, are dispersed with any sweeteners and water in the conventional mixer, until the mixture is It makes gel homogeneous. In the gel phase is added a pigment such as Ti02, any antibacterial agent such as triclosan, any antibacterial enhancing agent such as Gantrez, any tartar control agents such as tetrasodium pyrophosphate or sodium tripolyphosphate or both, in the second acid phosphate component and in the first component the source of fluoride ion, for example sodium fluoride. These ingredients are mixed until a homogeneous phase is obtained. Then, the thickener, the silica abrasive, the flavor and the surfactant ingredients are added and the ingredients are mixed at a high speed under vacuum of from about 20 to 100 mm Hg. The resulting product in the case of each component, a semi-solid and homogeneous extrudable paste product.

Toothpaste Packaging The multicomponent dentifrice composition of the present invention is packaged in a suitable stock container in which the components are kept physically separate and from which the separate components can be dispensed synchronously as a belt for application to a toothbrush. For the container are known in the art. An example of such a container is a container dispenser of compartments, such as a pump or tube, having foldable side walls, as described in US Pat. Nos. 4,487,757. and 4,687,663; wherein the container body is formed of a foldable plastic fabric and is provided with a part within the container body defining separate compartments in which the physically separated components are stored and from which they are dispensed through an outlet Proper supplier.

The following example is further illustrative of the present invention, but it is understood that the invention is not limited thereto. All the amounts and proportions mentioned above and in the appended claims are by weight unless otherwise stated.

Example A dentifrice of the components of the present invention was prepared, designated Dental Paste I having a first component containing silica abrasive and sodium fluoride and a second component containing silica phosphate acidic abrasive. The ingredients and pH of the two components of toothpaste I are determined in Table I below.

Table I Dental Paste I * Contains potentially 5000 parts per million F releasable with a combination of the first and second components with mixing before application to the denture. To determine the availability of the fluoride ion of the multicomponent toothpaste of the present invention, after storage for a period of weeks, the first and second components of the toothpaste were mixed together, diluted a thousand times using a commercially available buffer solution (Orion TIS II), at room temperature; the available fluoride ion concentration was determined using a Corning Model 350 idn / pH analyzer from Corning Inc., of Corning New Yor equipped with an Orion fluoride electrode, Model 94-09, Orion Research Products, of Boston, Massachusetts. The EMF output from the Orion fluoride electrode was converted to one million fluoride by means of a linear logarithmic calibration established with known concentrations of fluoride in the buffer and the available parts per million of the fluoride were determined and recorded in the fluoride. Table III given below.

For comparison purposes, the procedure was repeated except that the fluoride-tested dentifrice was an acidic phosphate fluoride toothpaste single component of the prior art containing a designated silica abrasive; toothpaste II having the ingredients and the pH listed in Table II given below Referring to Table II, note that the amount within the toothpaste II is one-half that of the first component of the toothpaste I so that a comparable potential of 5.00 parts per million of fluoride would be deliverable with the use of cad one. After a comparable eight-week storage, the soluble fluoride available from toothpaste II is tested using the same methodology as used for toothpaste I results are established and recorded in Table III below.

Table II Dental Paste II PH 5.0 Tabl III Availability of Fluoride Referring to Table III, the 4,900 parts per million are equivalent to 98% of fluoride availability of toothpaste I and 3,800 parts per million correspond to or equivalent of 76% of fluoride availability in dental pasture II. The difference of 22% in the fluoride available between the toothpaste I of the present invention and the toothpaste I comparatively significant and unexpectedly large. The magnitude d of the fluoride loss available in toothpaste II is at a level of making the significance of toothpaste II unacceptable commercially.

Claims (12)

R E I V I ND I C A C I O N S

1. A method for tooth fluoridation using a 2-component dentifrice system comprising the steps of (1) preparing a first dentifrice component containing a sodium fluoride, the d fluoridation source and having a pH of less than about 7.5 and a second component of dentifrice containing a source of phosphate ion and an acid in an amount sufficient to maintain the pH in the range of about 2.5 to about 5.0; both dentifrice components contain a siliceous abrasive; (2) Keep the dentifrice components first and segund separated from each other until application to the teeth that require fluoridation; (3) Mix the first second components together to form a mixture that has a pH of about 4.0 around 6.0, (4) apply the mixture to the teeth, so the increased availability of fluoride ions for dental enamel is observed.

2. The method as claimed in clause 1, characterized in that the source of phosphate ions and phosphoric acid, sodium monobasic phosphate or a combination d thereof.

3. The method as claimed in clause 1, characterized in that the first component contains d from about 0.1 to about 3.0% by weight of sodium fluoride.

4. The method as claimed in clause 1, characterized in that the component contains from about 0.7 to about 4% by weight of an acid phosphate and an acid salt.

5. The method as claimed in clause 4, characterized in that the acid phosphate is a phosphoric acid and the acid salt is a sodium monobasic phosphate.

6. The method as claimed in clause 1, characterized in that the pH of the first component e is at least about pH 8.0.

7. The method as claimed in clause 1, characterized in that the acid is in a sufficient amount to maintain the pH of the second component in the range of about pH 3.5 to around pH 4.5.

8. The method as claimed in clause 1, characterized in that the siliceous abrasive is a precipitated amorphous hydrated silica. *

9. The method as claimed in clause 8, characterized in that the dentifrice composition contains from 10 to about 30% in total amorphous hydrated silica abrasive.

10. The method as claimed in clause 9, characterized in that in addition to the system components of the dentifrice, each contain 15.35% by weight of amorphous hydrated silica abrasive.

11. The method as claimed in clause 1, characterized in that a surfactant and both components of the dentifrice system are incorporated.

12. The method as claimed in clause 11, characterized in that the surfactant incorporated in the first component of the dentifrice system is sodium lauryl sulfate and the surfactant incorporated in the second component of dentifrice is a condensate of sorbitan acid esters 20 fatty acids of an ethylene oxide. SUMMARY A method for increasing the availability of fluoride using a system of acidic doped toothpaste in which the first component contains sodium fluoride and a silica abrasive in an alkaline environment and the second component contains an acid, an ion source, is described. phosphate and a silica abrasive.