MXPA00000402A - Stable aqueous abrasive peroxide tooth whitening dentifrice - Google Patents

Abstract

An aqueous abrasive whitening composition containing a peroxide whitening compound which is chemically and physically stable and exhibits heightened and rapid whitening of teeth and stain removal which comprises a combination of water, calcined alumina abrasive and a peroxide compound.

Description

DENTÍFRICO BLOCKER OF TEETH DB PEROXIDE ABRASIVE STABLE AQUEOUS BACKGROUND DB THE INVENTION Field of the Invention This invention relates generally to peroxide-containing preparations for bleaching human teeth, and more particularly, to a stable peroxide dentifrice composition which when applied to the surface the teeth are applied to act, whiten and remove tooth stains.

The previous art A tooth is composed of a layer of internal denti and a layer of outer hard enamel which is the protective ca of the teeth. The enamel layer of a naturally white tooth that is opaque or slightly discolored. Enamel coat can stain or discolor. The tooth enamel layer is composed of hydroxiapati mineral crystals that create a somewhat porous surface. It is believed that the porous nature of the enamel layer is what allows the staining agents and bleaching substances to permeate the enamel to discolor the tooth.

Many substances that a person confronts or contact with on a daily basis can "stain" or reduce the "whiteness" of the teeth. In particular, food, tobacco products, and fluids such as tea and coffee tend to stain teeth. These spots tend to accumulate on the enamel layer of the teeth and to form a film on the teeth. This staining and bleaching substances can permeate the enamel layer. This problem occurs gradually over many years but imparts noticeable discoloration to the enamel of teeth one. There are commercially available non-abrasive g compositions for the use of dentifrices which contain 1-by weight concentrations of hydrogen peroxide or urea peroxide when brushed on the teeth and bleaching and stain removal.

A disadvantage of the use of these peroxide-based bleaching gels is the tendency of a peroxide composition to decompose within a relatively short period of time after manufacture with the concomitant loss of all or a substantial amount of available oxygen thus limiting the effectiveness of some products with teeth whitening compositions. The peroxide compounds such as hydrogen peroxide are notoriously unstable with respect to the maintenance of the peroxide level. It has been found that it is very difficult to formulate the aqueous gels pastes which have an adequate shelf life and yet will easily release the oxygen when applied to the teeth. Therefore, the prior art, for example the patents of the United States of America Nos. 4,988,450 3,657,413 when formulating oxygen-releasing compositions for bleaching teeth, use anhydrous or past powders or water-free gels which must be protected in cont of the chemical interaction. The disadvantage of the use of such anhydrous product is that due to the absence of water, the application of the product tends to dry the oral tissue which leads to irritation and tissue damage. In addition, due to the absence of water in the formula, the anhydrous product, the exhi product relict properties are often unacceptable and poor due to inadequate hydration of the aggregate gelaci agents to thicken the product.

Dentifrice bleaching products formulated with peroxide compounds usually do not contain abrasive polishing agents since such materials activate rapid decomposition of the peroxy compounds so that oxygen bleaching agent is released prematurely. Evolution of the gas is especially undesirable since the evolution of the gas can cause swelling and / or stalli of the tubes containing the toothpaste product. Tubes capped and filled with toothpaste containing peroxide compounds and silica abrasives have been known to explode in a day after filling. US Pat. No. 5,256,402 discloses that when alumina abrasives are replaced by silica, the filling product is packaged with gas bubbles within a few days of the filling.

A disadvantage for the use of bleaching products which are formulated without abrasives is that in addition to the problem of stability, the products are not effective for the removal of stains. Therefore, the abrasive or polishing agent incorporated in a dentifrice acts to debride and physically scrape the outer surface of the teeth. This scraping action removes the bacterial film layers of plaque, as well as some of the stains and pigment bleach that are on the teeth that cause undesired discoloration. These abrasive agents also microdegrade the teeth to polish the teeth as to give the enamel a more lustrous appearance and superior optical brightness. This microabrasion action increases the ability of the scrubbed teeth to reflect white light and thus appear brighter.

The aqueous abrasive toothpaste composition described in the United States of America patent No No. 5,256,402 contains a urea or a hydrogen peroxide compound, an alkali pyrophosphate salt and a calcium pyrophosphate abrasive which is stable with respect to the active oxygen level. A disadvantage of the oral abrasive peroxide composition described in U.S. Patent No. 5,256,402 is that even when the peroxide compound is stable, additional stability is required when the product is subjected to extended storage periods. abnormally high temperatures.

In the co-pending patent application, series N No. 08 / 692,841 filed on August 2, 1996 is described as a dentifrice composition that provides an aqueous abrasive that is physically and chemically stable and performs a rapid whitening of the teeth and a stain removal, which contains phosphate dicalcium abrasive, a peroxide compound, humectant containing a polyethylene glycol, a metal ion complexing agent, an antioxidant compound and polyoxyethylene polyoxypropylene block copolymer gelation agent, the pH of the dentifrice being buffered in the range of about 5.8 to about 7.2.

Even when the aqueous abrasive peroxide tooth composition of the co-pending application, Series No. 08 / 692.8 is effective for teeth whitening, the art continues to search for dentifrice compositions of greater whitening and stability efficacy.

SYNTHESIS OF THE INVENTION According to the present invention, it has now been found that an aqueous and chemically stable peroxide dentifrice composition which performs a rapid whitening of the teeth and a removal of the stains is obtained using a calcined alumina abrasive, composite of peroxide and a stabilizing compound.

The stability of the dentifrice composition of this invention is unexpected, since as previously discussed, the prior art (US Pat. No. 5,256,402) understood that dentifrices containing peroxide compounds and alumina abrasives have a stable stability. .

DESCRIPTION OF PREFERRED INCORPORATIONS It is critical to the practice of the present invention that the alumina form used as the abrasive in the dentifrice compositions of the present invention is calcined alumina, of alumina produced by the calcination of aluminum hydroxy in alpha-Al203 which is thermodynamically stable. above 1200 ° C. Calcined alumina abrasives are commercially available. A calcined aluminum abrasive preferred by Alean Chemicals under the designation Baco Aluminum Oxide.

The calcined alumina abrasive is incorporated into the bleaching composition of the present invention at a concentration of from about 1 to about 30% by weight, preferably about 5 to about 10% by weight.

The peroxide component of the composition of the invention is included in an amount sufficient to allow the release of sufficient oxygen during the brushing of the teeth to effect the bleaching thereof. Typically the peroxide compound can be employed in the composition of the present invention in amounts such that at least about 0.5% of the composition comprises a peroxide., the peroxide comprises from about 0. to about 10% by weight of the composition. Preferably, the peroxide comprises from about 0. to about 5% by weight of the composition. Examples of the suitable peroxide compounds used to prepare the compositions of the present invention include metal peroxides such as calcium peroxide, hydrogen peroxide, organic peroxides including urea peroxides, peroxide glyceride, benzoyl peroxide and the like. A preferred peroxide compound is a hydrogen peroxide.

The calcined alumina abrasive peroxide used to prepare the bleaching composition of the present invention is dissolved or suspended in a water-borne compound such as polyethylene glycol, polyglycerin. The a constitutes about 7 to about 40% of the bleaching composition of the present invention and preferably from about 20 to about 30% by weight.

Illustrative of the polyethylene glycols useful in the practice of the present invention are those which include polyethylene glycols known under the Carbowax maze, which are nonionic polymers of ethylene oxide having the general formula: HOCH2 (CH2OCH2) I1CH2? H wherein n represents average number of oxyethylene group. Carbowax polyethylene glycol are designated by a number such as 400, 600, 80 1000, 2000 which represent the average molecular weight. The molecular weight range of the polyethylene glycols as mentioned herein is from about 200 to about 200 and preferably about 600 hereinafter referred to as polyethylene glycol 600.

The polyethylene glycol component included in the composition of the present invention constitutes about about 30% by weight of the bleached composition preferably about 15 to about 20% by weight. Glycerin can be included in the bleaching composition of the present invention in the range of from 0 to about 10% by weight of the bleaching composition. Glycerin concentrations essentially in excess of 10% by weight have been found to cause physical destabilization (liquefying of the composition and therefore such excess should be avoided.

The gelling agents are included in the abrasive peroxide compositions of the present invention amounts of from about 10% to about 25% per po of the composition and preferably from about 12 to about 20% by weight. Examples of suitable gelation agents include polyethylene polypropylene block copolymers having the formula HO (C2H4O) b (C3H60) m (C2H4O) bH where a is an integer such that the hydrophobic base represented by ^ HgO) has a weight molecular of around 2750 to 4000, b is an integer so that hydrophilic part represented by (C ^ 0) constitutes about 70-80% by weight in sopolymer. The block copolymers of this composition are commercially available under the Pluronic Sea F.

Pluronic F 127, which has a molecular weight in the range of about 9000 to about 14,000 and 70% of a hydrophilic polyethylene half is preferred for use as a gelation agent in the practice of the invention. Other examples of the The gelatin agents which can be used are the carboxymethyl polymers, which have very high molecular weight, and which are sold under the Carbopol somersaway por BF Goodrish Chemic Company, as well as the carboxypolymethylene polymers, which comprise a major part of one or more alpha-beta-olefinisation unsaturated carboxylic acids, and a minor pair of a polyalkenyl polyether or a polyol, for example, aspolymer or ashy acid bound together in sruzada form they are from around 0.75% to 1.5% polyalil susrosa.

The presensia of the stabilizing antioxidant stabilizers (oxygen scavengers) and metal ion chelating agents in the tooth-like denatures of the present invention contributes to the chemical stability of the abrasive peroxide composition. Examples of suitable metal ion chelating agents include alsali metal stannates such as sodium and potassium stannate, ethylene diamine tetrasetiso acid and salts thereof. Examples of antioxidants useful in the practice of the present invention include butylated hydroxytoluene (BHT), nordihydroguaiarétic propyl gallate and trihydroxybutyrophenone. The metal ion chelating agents are incorporated in the compositions of the present invention at a concentration of about 0.01 about 1% by weight and the oxidant is insorporated or concentrated from about 0.05 to about 0.20% by pe and preferably around from 0.020 to about 0.05% p weight.

In the preparation of the abrasive peroxide compositions of the present invention, the pH of the somposision is adjusted to a range between about 3.0 and about 8, preferably between about 5 and about 7.

Pyrophosphate salts having an antisack effluent such as dialkali or tetraalisaline metal pyrophosphate salts such as Na4P207 (TSPP), K4P207, Na2K2P207, Na2H2P2 (SAPP), and K2H2P207, can be included in the somposision of the present invention at a concentration of about 0.5 about 8.0% by weight and preferably about 1. to 3.5% by weight. In addition to the anticalculus efficacy, the pyrophosphate salts serve a dual function as complementary metal ion complexing agents.

Fluoride salts having an anti-caries effect can also be incorporated into the dentifrice of the present invention and are characterized by their ability to release fluoride ions in water, for example, sodium fluoride, potassium fluoride, fluorosilicate. of sodium, ammonium fluorosilisate and sodium monofluorophosphate (NaMFP) It is preferred to use a fluoride salt to release about 10-1500 parts per million of fluoride ion.

Also included is a surfactant in bleaching composition of the present invention and serves as a solubilizing, dispersing, emulsifying and wetting agent is especially effective to solubilize the flavor ingredient present. Surfactants, which can be used in the practice of the present invention include cationic surfactants, anionic surfactants such as sodium lau sulfate and sodium lauryl sulfoacetate, ampholytic and amphoteric surfactans such as cocoamidopropyl betaine.

The flavor ingredient constitutes about 0.5-5.0% by weight of the dentifrice composition of the present invention. The constituents of suitable flavor are the flavoring oils, for example, the oils of yerbabuena, men piperita, piróla, menthol, cineole, limonene, menthone and asetato.

A sweetening agent is preferably also employed as a somplement for the flavoring material. Suitable sweetening agents are soluble in water and include sodium saccharin, sodium cyclamate, xylitol, and the like aspartame, in consensions of about 0.1 to 1.0% weight. Sodium saccharin is preferred.

To prepare the bleaching compositions of the present invention, the water soluble salts, such as sodium saccharin and sodium monofluorophosphate (NaMFP) s dissolved in an aqueous vehicle containing a humectant t such as PEG 600 and glycerin. The vehicle is heated to a temperature of 130-170 ° C, followed by the addition of a polyoxyethylene polyoxypropylene block copolymer gelatin agent and the ingredients are mixed until the gel phase is formed. An abrasive compound such as calcium pyrophosphate is added to the gel and mixed to form a paste when formed and cooled to about 90-130 ° preferably about 100 ° F. A metal chelating agent, antioxidant, a buffering agent and a peroxide compound are then added to the paste and the ingredients mixed to contain a homogeneous mixture. The flavor and surfactant are then added to the mixture to obtain a whitening paste of the finished teeth of the present invention. It has been determined that when the pyrophosphate salts are used in the manufacture of the bleaching compositions of the present invention, attempts to dissolve such salts in the aqueous vehicle at temperatures in excess of 130 ° F should be avoided since such temperature conditions bring levels of pyrophosphate salts in excess of the solubility layer of the salt thus causing a super saturated sdsion with respect to the excess salt. During storage, lower environmental temperatures, the excess pyrophosphate salt crystallizes out of the bleaching matrix, forming an insoluble solid matter which is cosmetically unacceptable and may have the added disadvantage of promoting chemical instability.

It is therefore preferred in the practice of the present invention, that when the pyrophosphate salts are included in the bleaching formula that during the manufacture of the bleaching composition, any pyrophosphate salt added to the composition is pre-mixed in humectant and the Mix is added to the composition at temperature no greater than 100 ° F.

The following examples further illustrate the present invention, but it is understood that the invention there is limited. All amounts and proportions mentioned herein in the appended claims are by weight unless otherwise indicated.

EXAMPLE 1 An abrasive bleaching peroxide of the present invention containing salsinate alumina is designated "Composisidr. A". For comparative purposes, a comparative whitening peroxide dentifrice (Composition in the same manner as Composition A except for the calcined alumina that was not present as an abrasive.) L ingredients of the compositions A and B are recorded in Table 1. given below.

Compositions A and B were prepared by dispersing the TSPP in a mixture of PEG 600 and glycerin by heating at 130 ° F with stirring. The water was added to the mixture and the ingredients were mixed for about minutes. Saccharin and sodium monofluorophosphate (Na MFP were added and the resulting mixture was stirred for 10 minutes followed by the addition of Pluronic F127 and stirring at 130 ° for 20 minutes.The mixture was then deaired for 5 minutes the calcium pyrophosphate was Aggregate and the resulting paste mixed for 15 minutes at high speed under vacuum.potassium stannate pre-mixed with H202 was added to the pas with additional mixing for 10 minutes with a high speed The BHT pre-mixed with the flavor oil was then added to the paste and mixed under vacuum for 5 minutes.Sulfa lauryl sodium (SLS) was then added under vacuum for minutes at low speed.As necessary, the phosphoric acid was added to adjust the pH of the composition to the wanted.

The chemical stability of the A and b somposisions was determined by initially analyzing the composition with respect to oxygen astivo (AO) and then slaking the compositions for a period of 6 weeks at temperatures raised to 105 ° F, 120 ° F and again analyzing the toothpaste with respect to active oxygen.

The results of these analyzes are summarized in Table II given below.

TABLE II Composition Stability Active Oxigcco% Ox eoo active% 6? M * nu @ Recovery% active oxygen Composition 105- * F. 120-F. 10S ° F. 120 ° F. 105'F. 120 ° F.

A 1.49 1.49 1.40 1.31 94.0 87.9 B 1.19 1.19 1.06 1.01 89.0 84.9 The data recorded in Table II indicate stability of the peroxide dentifrices of the present invention (Composition A) containing calcined alumina abrasive which is 94% after 6 weeks at 105 ° F and more than 8 after 6 weeks at 120 ° F indicating that the dentifrice composition is relatively stable and still has a superior stability than a similar dentifrice (Composition B) in which calcined alumina is absent.

To test the bleaching efficiency of Composition A, bovine teeth were stained by intermittent exposure of bovine teeth to a stained broth containing finely ground, instant, instant coffee, gastric mucin, trypticase, soy balance, Sarcina lutea turtox (a chromogenic microorganism) through a 4 day period. The specimens of stained bovin teeth selected for the test show the same amount of discoloration. The selected specimens were then brushed with a 1: 1 toothpaste / water solution for 20 brush strokes. The bleached eficasia was determined by increasing the L value measured by a Minolta sronometer before and after brushing. L is a measure of the eye's response to light and darkness. A change in L (? L is then calculated.) The value? L between higher, more blans appear in the teeth.

For comparison purposes, the blanking evaluation procedure of the example is repeated except that composition B was replaced by composition A.

The results of the brushing study using the samples of stained bovine teeth are shown in Tab III.

The data in Table 3 indicate that the dentifrice of the present invention (Composition A) containing calcined alumi is essentially more effective (52%) in removing stain from the teeth than the comparative composition B which contained the calcined alumina, the results They are statistically significant at a 95% confidence level.

Claims (10)

R E I V I N D I C L I O N E S

1. An aqueous whitening composition of the teeth which is chemically stable and bleaching in the removal of manshas from the teeth suals the vehicle containing water as a humectant, a salty aluminum abrasive and a peroxide solution.

2. The composition as claimed in clause 1, characterized in that the peroxide is hydrogen peroxide.

3. The composition as claimed in clause 1, characterized in that the compound is present at a concentration at a concentration of about 0.5 about 10% by weight of the somposission.

4. The composition as claimed in clause 1, sarasterized in that the calcined alumina is present in the composition at a concentration of about 30% by weight of the composition.

5. The composition as claimed in clause 1, characterized in that the water is present in the suspension at a concentration of about 7 to about 40% by weight.

6. A method for whitening the cu teeth comprises preparing a bleaching solution of the aqueous dient containing a calcined alumina abrasive and peroxide compound which is chemically and physically then applying the composition to the stained teeth for bleaching and bleaching. the removal of the stains of the teeth.

7. The method as claimed in clause 6, characterized in that the peroxide is hydrogen peroxide.

8. The method as claimed in clause 6, characterized by the peroxide composition is present in the combination at a concentration of 0.5% about 10% by weight of the composition.

9. The method as claimed in clause 6, characterized in that the calcined alumina abrasive compound is present in the suspension at a concentration of from about 1 to about 30% by weight.

10. The method as such is claimed in clause 6, characterized in that water is present in the composition at a concentration of about 7 to about 40% by weight. SUMMARY A brazing abrasive bleaching composition which contains a peroxide bleaching compound is both chemically and physically stable and exhibits rapid increased bleaching of teeth and stain removal comprising a combination of water, calcined alumina abrasive and composite of peroxide.