CA2103181A1 - Oral composition having improved tooth whitening effect - Google Patents
Oral composition having improved tooth whitening effectInfo
- Publication number
- CA2103181A1 CA2103181A1 CA002103181A CA2103181A CA2103181A1 CA 2103181 A1 CA2103181 A1 CA 2103181A1 CA 002103181 A CA002103181 A CA 002103181A CA 2103181 A CA2103181 A CA 2103181A CA 2103181 A1 CA2103181 A1 CA 2103181A1
- Authority
- CA
- Canada
- Prior art keywords
- composition
- acid
- percarbonate
- teeth
- oral
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
Classifications
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
- A61K8/00—Cosmetics or similar toiletry preparations
- A61K8/18—Cosmetics or similar toiletry preparations characterised by the composition
- A61K8/30—Cosmetics or similar toiletry preparations characterised by the composition containing organic compounds
- A61K8/33—Cosmetics or similar toiletry preparations characterised by the composition containing organic compounds containing oxygen
- A61K8/38—Percompounds, e.g. peracids
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
- A61K8/00—Cosmetics or similar toiletry preparations
- A61K8/18—Cosmetics or similar toiletry preparations characterised by the composition
- A61K8/30—Cosmetics or similar toiletry preparations characterised by the composition containing organic compounds
- A61K8/33—Cosmetics or similar toiletry preparations characterised by the composition containing organic compounds containing oxygen
- A61K8/37—Esters of carboxylic acids
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61Q—SPECIFIC USE OF COSMETICS OR SIMILAR TOILETRY PREPARATIONS
- A61Q11/00—Preparations for care of the teeth, of the oral cavity or of dentures; Dentifrices, e.g. toothpastes; Mouth rinses
Abstract
ABSTRACT
The present invention provides an oral composition for whitening teeth comprising a safe and effective whitening amount of peracetic acid dissolved or suspended in a vehicle, wherein the peracetic acid is generated within the vehicle in situ by combining water, acetylsalicylic acid and a water soluble alkali metal percarbonate.
The present invention provides an oral composition for whitening teeth comprising a safe and effective whitening amount of peracetic acid dissolved or suspended in a vehicle, wherein the peracetic acid is generated within the vehicle in situ by combining water, acetylsalicylic acid and a water soluble alkali metal percarbonate.
Description
21~31g~
ORAL COMPOSlTION HAVING IMPROVED TOOTH WHlTENING E~ECT
SBACKGROUND OF THE INVENTION
-1. Field of the Invention This invention relates generally to an oral composition which when applied onto the 10 surface of teeth acts to whiten teeth and more particularly to an oral composition for whitening teeth that is more effective than existing products available to the consumer. ~ -2. The Prior Art 15 A tooth is comprised of an inner dentin layer and an outer hard enamel layer that is the protective layer of the tooth. The enamel layer of a tooth is naturally an opaque white or slightly off-white color. It is this enamel layer that can become stained or discolored.
The enamel layer of a tooth is composed of hydroxyapatite mineral crystals that create a somewhat porous surface. It is believed that this porous nature of the enamel layer is 20 what allows staining agents and discoloring substances to permeate the enamel and discolor the tooth.
. . .
Many substances that an individual comes in contact with on a daily basis can "stain" or reduce the "whiteness" of one's teeth. In particular, foods, tobacco products and fluids 25 such as tea and coffee that one consumes tend to stain the teeth. These products or substances tend to accumulate on the enamel layer of the tooth and form a pellicle film over the teeth. These staining and discoloring substances can then permeate the enamel layer.
30 One method for whitening teeth used by dental professionals involves the use of 30%
hydrogen peroxide in combination with heat and light to promote the oxidation reaction.
This method, although fast, is losing favor with dentists because clinical and scientific evidence shows that an effective whitening process without heat and light is desired.
35 Another professional method for bleaching teeth involves the use of hydrogen peroxide generating compounds such as urea peroxide (carbamide peroxide) at concentrations of .~ 2~a3lgl ' 10% to achieve the desired whitening effect. Urea peroxide rapidly breaks down into hydrogen peroxide due to the water present in saliva. This method is known as anoffice-monitored at-home bleaching system and involves the use of a mouth guard or tray within which the bleaching agent is placed. The tray is then placed upon the teeth 5 of the user and bleaching is allowed to take place. This method of treatment has drawbacks including tooth sensitivity, possibly due to demineralization and irritation of oral tissues. An additional disadvantage of the tray application method is that the bleaching effect is very slow.
10 There is a demand in the marketplace for a tooth whitening product that can be used at home or in private by the consum and is safe and easy to use. A product for home use should not utilize the compositions or products for whitening teeth that are available for use by a trained dental professional. For example, thè 30% hydrogen peroxide bleaching agent utilized by many dental practitioners to bleach teeth is sufficiently lS concentrated to be irritating and potendally dangerous for home use by the consumer.
More reeently it has been discovered that peracetic acid is a surprisingly effective bleaehing or whitening agent for diseolored or stained human teeth, as disclosed in copending Canadian Patent Appllcation Serial No. 2,083,409, filed November 20, 1992. AS
deseribed in that application, 1% by weight aqueous solution of peraeetie aeid gives rise to a faster and superior whitening effect when applied to teeth at ambient to oral range temperatures than does a 30% by wdght aqueous solution of hydrogen peroxide. As also described in the above referenced application, the peracetie acid can be applied 25 direetly to the teeth as by swab application, incorporated in an oral composition such as a toothpaste, gel or rinse that is to be applied topically, or generated in situ in the oral eornposition by the reacdon of a peroxide source such as hydrogen peroxide, ureaperoxide, sodiurn perborate, sodium percarbonate, and metal peroxides, for example, SrO~, Ca02 and Na02, with a peroxyaeid precursor or wdvator eontaining labile acetyl 30 groups. Illustrative examples of such activators include tetracetylethylenediamine, pentaacetylglucose, tetraeetylglycoluril, sorbitol hexaacetate or fructose pentaacetate.
One of the major disadvantages associated with the use of peracetie acid paekaged for home use by the eonsumer is its reladve instability. Dilute 19'o aqueous solutions of 35 peracetic acid will substantially decompose in as little as 30 days at ambient temperatures. Storage at 3C significantly improves stability but not to the extent : -: ~ ' .. .. . . . . ... .
~-' 2~ ~318~ 62301-1854 required for the normal market age for a consumer or professional product. In addidon, many common adjuvants present in consumer and professional products such as flavorants and other organic materials can rapidly react with peracetic acid, destroying both the adjuvants and the peracetic acid.
S
These factors tend to dictate that a preferred approach for the employment of peracetic acid chemistry in dentifrice applications is to generate the peracetic acid in-situ at the dme of use. A source of hydrogen peroxide and a carboxylate derivative of acetic acid, such as an amide or an ester, may be mixed together in water at a pH high enough to 10 generate sufficient concentradon of perhydroxyl anion from the hydrogen peroxide The perhydroxyl anion nucleophilically attac~s the acetate derivative producing peracedc acid in accordance with the following reacdon:
- :.-~ O
R-CCH3 +-OOH -OO~CH3 ~ RH
Analogous chemistry has been employed to generate hydrogen peroxide and perorganic acids in dry bleach and laundering composidons. For example, Bridsh Patent 836,988 discloses texdle bleaching compositions containing an inorganic H202 source such as 20 sodium perborate or sodium percarbonate and an organic carboxylic acid ester such as esters of phenols or esters of mono - or disaccharides containing 3 or more ester ;
groups.
The in-situ approach towards generadng peracedc acid has also been disclosed with 25 respect to dentifrice composidons as described in Canadian Patent Appli- ~ .
catlon Serial No. 2,083,409, referred to above.
, In addition, U.S. Patent No. 5,0SS,30S discloses effervescent tablets for the in vitro cleaning of dentures which contain, as essendal components, a bleaching agent which comprises salts of persulfate perborate or pyrophosphate hydrates or metal peroxides, a peroxyacid bleach precursor and an effervescence - producing base composidon.
Among the numerous organic peracid precursors disclosed are carboxylic acid esters such as acetylsalicylic acid, which are more generally disclosed in the aforemendoned British Patent 836,988, directed towards textile bleaching and detergent composidons.
In those applicadons where dendfrice composidons are designed for in-vivo use, it is ; ~ ~
',.~ ' A~ S ~
2 ~L 3 essential that the peracetic acid generating components react quickly after they are combined, since the user will normally wish to limit the tirne in which the dentifrice is in contact with the teeth. In addition, the classes of peroxide generators and peroxy acid bleach precursors useful for in-vivo applicadon to the teeth is severely limited due to the S requirement that these components be physiologically safe and non-irritating to oral tissues. A further requirement for in-vivo use is that the peracetic acid is generated at a relatively neutral pH, close to the safe physiological neutral pH of 7.
SUMMARY OF THE INVENTION
The present invention provides an-oral composition for whitening teeth comprising a safe and effective whitening amount of peracetic acid dissolved or suspended in a vehicle, wherein the peracetic acid is generated within the vehicle in situ by combining water, acetylsalicylic acid and a water soluble alkali metal percarbonate.
The present invention offers the advantages that the peracetic acid is generated quickly ant in large quantities and at a relatively low pH of less than about 9.0, thereby facilitadng convenient and effective home use by the consumer as well as professional use by the dentist.
DETALEI2~nON OF THE INVENTION
The hyd-ogen peroxide source used in the compositions of the invendon is a watersoluble alkali tnetal percarbonate such as sodium or potassium percarbonate. The25 prefer ed hydrogen peroxide source is sodium percarbonate, also referred to as sodium carbonate peroxyhydrate, having the chemical formula 2Na2C03 3H202. This material is particularly prefelTed because it is highly water soluble and dissolves quickly to react with acetylsalicylic aeid to generate peracetic acid and also provides a source of all~alinity in the ~eaction medium The peracetic aeid precursor used in combination with the percarbonate is acetylsalicylic acid (ortho-acetoxybenzoic acid), more commonly known as aspirin, and having thechemical formula CH3C00C6H4C00H.
35 The pe~arbonate and aeetylsalicylic aeid components are each co~r~nereially available in fine powder form in both technical and pharmacological grades. When these 2:l331~1 components are dissolved in water at temperatures of 20 to 25C, they quickly react to generate peracetic acid as a consequence of the nucleophilic attack by the perhydroxyl anion on the acetyl ester group of the acetylsalicylic acid. The presence of a carboxylic acid group on the acetylsalicylic acid molecule tends to neutralize some of the alkalinity 5 generated as the result of the decomposition of the percarbonate, thereby resulting in a soludon pH of less than 10, and generally in the range of from about 8.0 to about 9Ø
To enhance the performance of the peracedc acid as a whitening agent it is desirable to adjust the pH of the oral composition to the acid range, i.e. below pH 7.0 and 10 preferably a pH of about 5.0 to about 6.5. To adjust the pH, any non-toxic acid or acid salt may be added to the oral composidon. Preferably materials such as citric acid, tartaric acid, partial salts of these acids, monosodium hydrogen phosphate may'be added to the oral compositions to obtain an acid p~
15 The amount of peracetic acid incorporated in the oral compositions may vary depending upon intended use. For use by trained professionals in office treatments, the coneentradon of peracedc acid may range from about 0.25 to 5% by weight. For home use, lower concentradons of peraeede acid are dietated, generally in the range of from about 0.01 to about 0.50% by weight. Transladng these values into the content of20 peracedc aeid preeursors required to generate such quantides of peracetic acid, the oral compositions may contain from about 0.5 to about 35% by weight of the combination of alkali metal perearbonate and acetylsalicylic acid incorporated therein, more preferably from about 1 to about 20% by weight. The preferred weight ratio of alkali metal perearbonate to aceqlsalicylic aeid may range from about 4:1 to 1:4. The more 25 preferred weight rado of sodium perearbonate to acetylsalieylie acid lies in the range of from about 1:1 to about 2:1, most preferably about 1.6:1.
The vehiele used for preparing the oral eompositions of the present invention may inelude water, water-containing oral rinses, pastes, gels and similar forms as are known in the art. For professional or home use, measured quanddes of the percarbonate and 30 acetylsalicylic acid can be individually dissolved in water and permined to reaet to form a soludon having the desired concentration of peracedc acid, e.g., a concentration of from about 0.1 to about 5% by weight. For professional use, this solution can additionally be gelled using fumed silica or a nonionic gellant such as hydroxyethylcellulose, and applied to the patdent's teeth by the dendst. A pardcularly 35 preferred adaptadon is the provision of a dry powdered mixture of these components or a muldlayer tablet wherein one layer contains the peracarbonate component and a 2~3181 different layer contains the acetylsalicylic acid component.
Where the oral composition is in the form of a paste or gel wherein the vehicle already contains some water, such as a tooth paste, quite clearly the reacdve components must 5 be separated to avoid chemical reaction prior to use by the consumer. Such an oral composition can be provided in the form of at least two separate, unmixed carrier phases, including a non-aqueous phase containing the percarbonate and an aqueousphase containing the aoetylsalicylic acid. Such separadon can also be provided by encapsulating one or both components in a material which will dissolve in water or 10 fracture when the composidon is used by the consumer.
Gels or pastes formulated to contain the acetylsalicyclic acid ing~dient of this invendon may also include a gelling agent such as a polyoxyethylene-polyoxypropylene block copolymer, a humectant such as glycerine, sorbitol or a polyethylene glycol, a nonionic 15 surfactant, sweetener and flavorant. Water may be present in the gel or paste and generally constitutes about 40-70% by weight of the oral composition. Distilled or deionized water is preferled to prevent minimal contaminadon.
Polyoxyethylene-polyoxypropylene block copolymers which are nonionic and useful 20 gdling agents in the oral compositions of the present invendon are represented by the formula:
H0(C2H4O)b(C3H60)b(C2H40)bH
25 wherein a is an integer such that the hydrophobic base represented by (C3H40) has a moleeular weight of about 2750 to 4000, b is an integer such that the hydrophilic pordon (moiety) represented by (C2H40) eonsdtutes about 70-80% by weight of the eopolymer. PluronieTM Polyols of the F (solid flake or powder) type are preferred.
30 Other useful thiekening agents include eolloidal carboxyvinyl polymers, cross-linked polycarboxylate polymers, polyvinyl pyrrolidone, and fumed silica.
The gelling agent may be present in the oral eomposition of the present invention at a eoneentradon of about 0.25 to about 40% by weight and preferably about 0.5 to about 35 30% by weight of the composition.
:. .''. : ~ :':,, :
, . : ~ - ,.. : :, 2 ~ 8 1 Illustrative of the polyethylene glycols useful as additives include polyethylene glycols known by the trademark CARBOWAXTM which are nonionic polymers of ethylene oxide having the general f~rmula:
HocH2(cH2cH2o)ncH2oH
wherein n represents the average number of oxyethylene groups. The CarbowaxTM
polyethylene glycols are designated by a number such as 400, 600, 800, etc. which represents the average molecular weight. The average molecular weight of the 10 polyethylene glycols used herein is about 200-1000, preferably 40~800 and most prefeMbly 600.
,- .
Other useful humectants include non-hydroxylated compositions such as capped polyethylene glycol, where the hydrogens on the hydroxyl groups have been replaced 15 with methyl groups. Humectants such as glycerine, sorbitol polyethylene glycol and capped polyethylene glycols may be included in the oMI composition of the present in~,rcntion at a concentration of about 10 to about 40% by weight and preferably about 15 to about 25% by weight of the composition.
. .. .
20 Surfactants such as anionic and nonionic compounds may be included in the oral compositions of the present invention to serve as a wetting, solubilizing and emulsifying agents. Particularly useful anion* surfactants include sodium lauryl sulfate, salts of '~ -dodecylbcnzcne sulfonate and sodium coconut monoglyceride sulfonatcs. A particularly uscful nonionic surfactant is a water soluble polyoxyethylene monocster of sorbitol with 25 a C10~l8 fatty acid cster of sorbitol (and sorbitol anhydrides), consisting prcdominantly of the monocster, condensed with about 10-30, preferably about 20, moles of ethyleneoxide. Thc fatty acid (aliphatic hydrocarbon-monocarboxylic acid) may besaturatcd or unsaturated, c.g. Iauric, palmitic, stearic or oleic acids. TweenTM 20 is especially prcfcrred, which is a polyoxyethylene (20) sorbitan monolaurate. Capped 30 polyalkylene oxide copolymer nonionic surfactants in which the hydrogens on the hydroxyl groups have been replaced with methyl groups are also useful in the present invendon. These types of surfactants are described in U.S. Patent No. 4,988,452 and U.S. Patent No. 4,877,544.
35 The surfactant constitutes about 0.1 to 5.0% by weight and preferably 0.5 to 3% by weight of the oral composition.
-::
- . . , . ..... , - ,. ~ . , . .. , . .,, .. , ., .. , .. - ,, . ; , - . , ~ ~ , .. ..
, ., .. "{.", ., ,.. ,,;~.,.. ,.. ".. .. ", ,.".. ,.. ,.. ., ;::, ..... . : .
-: ' 2~a3lsl ,.
A flavor ingredient may constitute about 0.5 to 5.0% by weight of the oral composition of the present invention. Suitable flavoring constituents are flavoring oils, e.g., oils of spearmint, peppermint, wintergreen, sassafras, clove, sage, eucalyptus, marjoram, 5 cinnamon, and methyl salicylate, ethyl acetate and menthol.
A sweetening material is preferably also employed as a complement to the flavoring material. Suitable sweetening agents are water soluble and include sodium saccharin, sodium cyclamate, xylitol, aspartame and the like, in concentrations of about 0.10 to 1.0% by wdght. Sodium saccharin is prefer ed.
'`"' Pyrophosphate salts having and-tartar efficacy such as a dialkali or tetra-alkali metal pyrophosphate salts such as Na4P207, K4P207, Na2K2P207, Na2H2P207 and K2H2P207, long chain polyphosphates such as sodium hexametaphosphate and cyelic phosphates such as sodium trimetaphosphate may also be ineorporated in the oral 15 compositions of the present invention preferably at a concentradon of about 0.5 to about 8.0% by wdght.
Peroxide stabilizers sueh as sequestering agents, buffers, aciduladng agents, coadng or eneapsulating agents may also be ineluded in the oral eompositions of the present 20 invention. Examples of suitable sequestering agents are salts of ethybnediaminetet~aacetic acid, diethylene triarninepentaacedc acid, phosphonates such as DEQUEST available from Monsanto Chemieal Company and azaeycloheptane 2', 2' diphosphonate. Such agents stabilize the peroxide eontaining compositions by chelating ~r;i1 r metal ions swh as Fe+3, Mn+2 and Cu+2, The agents may be incorporated in the ' ~'~
25 composidons of the present invendon at a eoneentradon of about 0.1 to about 6.0% by wdght of the eomposidon.
The eomposidon of the invendon may also be formulated into an effervescent tablet eomposidon for use in eleaning dentures. - In this embodiment the tablet would be 30 eomposed of an acidic layer containing the aeetylsalieylic acid component and an efferveseent such as sodium bicarbonate, and an allcalhe layer containing the aLI~ali metal perearbonate. Tablots of this type are diselosed in U.S. Patent 5,0S5,305.
The following Example 1 illustrates the enhaneed whitening effeet on human teeth of a 35 1% by weight aqueous peraeetie aeid solution as eompared with a 30% by weight aqueous soludon of hydrogen peroxide.
. ` .
9 21 "~
Examvle I
A Minolta CR-221 Chroma Meter was used to measure the optical properties of extracted human molars and after application of whitening agents.
S . ~
The whitening agents tested were: -1. The System - 5.5 grams of sodium percarbonate and 2.5 grams of -~ .. c aspirin were dissolved in 100 mL of water. After reacting for- 2-3 ~
minutes, 3.7 grams of citric acid were add¢d to give a solut~h with au' - ~s~ i~D
final pH of about 6.
2. 1% Peracetic acid - A solution of 1% peracetic acid in water was made -n in~
and pH adjusted to about 4 with sodium hydroxide.
1 5 . ., . ~
ORAL COMPOSlTION HAVING IMPROVED TOOTH WHlTENING E~ECT
SBACKGROUND OF THE INVENTION
-1. Field of the Invention This invention relates generally to an oral composition which when applied onto the 10 surface of teeth acts to whiten teeth and more particularly to an oral composition for whitening teeth that is more effective than existing products available to the consumer. ~ -2. The Prior Art 15 A tooth is comprised of an inner dentin layer and an outer hard enamel layer that is the protective layer of the tooth. The enamel layer of a tooth is naturally an opaque white or slightly off-white color. It is this enamel layer that can become stained or discolored.
The enamel layer of a tooth is composed of hydroxyapatite mineral crystals that create a somewhat porous surface. It is believed that this porous nature of the enamel layer is 20 what allows staining agents and discoloring substances to permeate the enamel and discolor the tooth.
. . .
Many substances that an individual comes in contact with on a daily basis can "stain" or reduce the "whiteness" of one's teeth. In particular, foods, tobacco products and fluids 25 such as tea and coffee that one consumes tend to stain the teeth. These products or substances tend to accumulate on the enamel layer of the tooth and form a pellicle film over the teeth. These staining and discoloring substances can then permeate the enamel layer.
30 One method for whitening teeth used by dental professionals involves the use of 30%
hydrogen peroxide in combination with heat and light to promote the oxidation reaction.
This method, although fast, is losing favor with dentists because clinical and scientific evidence shows that an effective whitening process without heat and light is desired.
35 Another professional method for bleaching teeth involves the use of hydrogen peroxide generating compounds such as urea peroxide (carbamide peroxide) at concentrations of .~ 2~a3lgl ' 10% to achieve the desired whitening effect. Urea peroxide rapidly breaks down into hydrogen peroxide due to the water present in saliva. This method is known as anoffice-monitored at-home bleaching system and involves the use of a mouth guard or tray within which the bleaching agent is placed. The tray is then placed upon the teeth 5 of the user and bleaching is allowed to take place. This method of treatment has drawbacks including tooth sensitivity, possibly due to demineralization and irritation of oral tissues. An additional disadvantage of the tray application method is that the bleaching effect is very slow.
10 There is a demand in the marketplace for a tooth whitening product that can be used at home or in private by the consum and is safe and easy to use. A product for home use should not utilize the compositions or products for whitening teeth that are available for use by a trained dental professional. For example, thè 30% hydrogen peroxide bleaching agent utilized by many dental practitioners to bleach teeth is sufficiently lS concentrated to be irritating and potendally dangerous for home use by the consumer.
More reeently it has been discovered that peracetic acid is a surprisingly effective bleaehing or whitening agent for diseolored or stained human teeth, as disclosed in copending Canadian Patent Appllcation Serial No. 2,083,409, filed November 20, 1992. AS
deseribed in that application, 1% by weight aqueous solution of peraeetie aeid gives rise to a faster and superior whitening effect when applied to teeth at ambient to oral range temperatures than does a 30% by wdght aqueous solution of hydrogen peroxide. As also described in the above referenced application, the peracetie acid can be applied 25 direetly to the teeth as by swab application, incorporated in an oral composition such as a toothpaste, gel or rinse that is to be applied topically, or generated in situ in the oral eornposition by the reacdon of a peroxide source such as hydrogen peroxide, ureaperoxide, sodiurn perborate, sodium percarbonate, and metal peroxides, for example, SrO~, Ca02 and Na02, with a peroxyaeid precursor or wdvator eontaining labile acetyl 30 groups. Illustrative examples of such activators include tetracetylethylenediamine, pentaacetylglucose, tetraeetylglycoluril, sorbitol hexaacetate or fructose pentaacetate.
One of the major disadvantages associated with the use of peracetie acid paekaged for home use by the eonsumer is its reladve instability. Dilute 19'o aqueous solutions of 35 peracetic acid will substantially decompose in as little as 30 days at ambient temperatures. Storage at 3C significantly improves stability but not to the extent : -: ~ ' .. .. . . . . ... .
~-' 2~ ~318~ 62301-1854 required for the normal market age for a consumer or professional product. In addidon, many common adjuvants present in consumer and professional products such as flavorants and other organic materials can rapidly react with peracetic acid, destroying both the adjuvants and the peracetic acid.
S
These factors tend to dictate that a preferred approach for the employment of peracetic acid chemistry in dentifrice applications is to generate the peracetic acid in-situ at the dme of use. A source of hydrogen peroxide and a carboxylate derivative of acetic acid, such as an amide or an ester, may be mixed together in water at a pH high enough to 10 generate sufficient concentradon of perhydroxyl anion from the hydrogen peroxide The perhydroxyl anion nucleophilically attac~s the acetate derivative producing peracedc acid in accordance with the following reacdon:
- :.-~ O
R-CCH3 +-OOH -OO~CH3 ~ RH
Analogous chemistry has been employed to generate hydrogen peroxide and perorganic acids in dry bleach and laundering composidons. For example, Bridsh Patent 836,988 discloses texdle bleaching compositions containing an inorganic H202 source such as 20 sodium perborate or sodium percarbonate and an organic carboxylic acid ester such as esters of phenols or esters of mono - or disaccharides containing 3 or more ester ;
groups.
The in-situ approach towards generadng peracedc acid has also been disclosed with 25 respect to dentifrice composidons as described in Canadian Patent Appli- ~ .
catlon Serial No. 2,083,409, referred to above.
, In addition, U.S. Patent No. 5,0SS,30S discloses effervescent tablets for the in vitro cleaning of dentures which contain, as essendal components, a bleaching agent which comprises salts of persulfate perborate or pyrophosphate hydrates or metal peroxides, a peroxyacid bleach precursor and an effervescence - producing base composidon.
Among the numerous organic peracid precursors disclosed are carboxylic acid esters such as acetylsalicylic acid, which are more generally disclosed in the aforemendoned British Patent 836,988, directed towards textile bleaching and detergent composidons.
In those applicadons where dendfrice composidons are designed for in-vivo use, it is ; ~ ~
',.~ ' A~ S ~
2 ~L 3 essential that the peracetic acid generating components react quickly after they are combined, since the user will normally wish to limit the tirne in which the dentifrice is in contact with the teeth. In addition, the classes of peroxide generators and peroxy acid bleach precursors useful for in-vivo applicadon to the teeth is severely limited due to the S requirement that these components be physiologically safe and non-irritating to oral tissues. A further requirement for in-vivo use is that the peracetic acid is generated at a relatively neutral pH, close to the safe physiological neutral pH of 7.
SUMMARY OF THE INVENTION
The present invention provides an-oral composition for whitening teeth comprising a safe and effective whitening amount of peracetic acid dissolved or suspended in a vehicle, wherein the peracetic acid is generated within the vehicle in situ by combining water, acetylsalicylic acid and a water soluble alkali metal percarbonate.
The present invention offers the advantages that the peracetic acid is generated quickly ant in large quantities and at a relatively low pH of less than about 9.0, thereby facilitadng convenient and effective home use by the consumer as well as professional use by the dentist.
DETALEI2~nON OF THE INVENTION
The hyd-ogen peroxide source used in the compositions of the invendon is a watersoluble alkali tnetal percarbonate such as sodium or potassium percarbonate. The25 prefer ed hydrogen peroxide source is sodium percarbonate, also referred to as sodium carbonate peroxyhydrate, having the chemical formula 2Na2C03 3H202. This material is particularly prefelTed because it is highly water soluble and dissolves quickly to react with acetylsalicylic aeid to generate peracetic acid and also provides a source of all~alinity in the ~eaction medium The peracetic aeid precursor used in combination with the percarbonate is acetylsalicylic acid (ortho-acetoxybenzoic acid), more commonly known as aspirin, and having thechemical formula CH3C00C6H4C00H.
35 The pe~arbonate and aeetylsalicylic aeid components are each co~r~nereially available in fine powder form in both technical and pharmacological grades. When these 2:l331~1 components are dissolved in water at temperatures of 20 to 25C, they quickly react to generate peracetic acid as a consequence of the nucleophilic attack by the perhydroxyl anion on the acetyl ester group of the acetylsalicylic acid. The presence of a carboxylic acid group on the acetylsalicylic acid molecule tends to neutralize some of the alkalinity 5 generated as the result of the decomposition of the percarbonate, thereby resulting in a soludon pH of less than 10, and generally in the range of from about 8.0 to about 9Ø
To enhance the performance of the peracedc acid as a whitening agent it is desirable to adjust the pH of the oral composition to the acid range, i.e. below pH 7.0 and 10 preferably a pH of about 5.0 to about 6.5. To adjust the pH, any non-toxic acid or acid salt may be added to the oral composidon. Preferably materials such as citric acid, tartaric acid, partial salts of these acids, monosodium hydrogen phosphate may'be added to the oral compositions to obtain an acid p~
15 The amount of peracetic acid incorporated in the oral compositions may vary depending upon intended use. For use by trained professionals in office treatments, the coneentradon of peracedc acid may range from about 0.25 to 5% by weight. For home use, lower concentradons of peraeede acid are dietated, generally in the range of from about 0.01 to about 0.50% by weight. Transladng these values into the content of20 peracedc aeid preeursors required to generate such quantides of peracetic acid, the oral compositions may contain from about 0.5 to about 35% by weight of the combination of alkali metal perearbonate and acetylsalicylic acid incorporated therein, more preferably from about 1 to about 20% by weight. The preferred weight ratio of alkali metal perearbonate to aceqlsalicylic aeid may range from about 4:1 to 1:4. The more 25 preferred weight rado of sodium perearbonate to acetylsalieylie acid lies in the range of from about 1:1 to about 2:1, most preferably about 1.6:1.
The vehiele used for preparing the oral eompositions of the present invention may inelude water, water-containing oral rinses, pastes, gels and similar forms as are known in the art. For professional or home use, measured quanddes of the percarbonate and 30 acetylsalicylic acid can be individually dissolved in water and permined to reaet to form a soludon having the desired concentration of peracedc acid, e.g., a concentration of from about 0.1 to about 5% by weight. For professional use, this solution can additionally be gelled using fumed silica or a nonionic gellant such as hydroxyethylcellulose, and applied to the patdent's teeth by the dendst. A pardcularly 35 preferred adaptadon is the provision of a dry powdered mixture of these components or a muldlayer tablet wherein one layer contains the peracarbonate component and a 2~3181 different layer contains the acetylsalicylic acid component.
Where the oral composition is in the form of a paste or gel wherein the vehicle already contains some water, such as a tooth paste, quite clearly the reacdve components must 5 be separated to avoid chemical reaction prior to use by the consumer. Such an oral composition can be provided in the form of at least two separate, unmixed carrier phases, including a non-aqueous phase containing the percarbonate and an aqueousphase containing the aoetylsalicylic acid. Such separadon can also be provided by encapsulating one or both components in a material which will dissolve in water or 10 fracture when the composidon is used by the consumer.
Gels or pastes formulated to contain the acetylsalicyclic acid ing~dient of this invendon may also include a gelling agent such as a polyoxyethylene-polyoxypropylene block copolymer, a humectant such as glycerine, sorbitol or a polyethylene glycol, a nonionic 15 surfactant, sweetener and flavorant. Water may be present in the gel or paste and generally constitutes about 40-70% by weight of the oral composition. Distilled or deionized water is preferled to prevent minimal contaminadon.
Polyoxyethylene-polyoxypropylene block copolymers which are nonionic and useful 20 gdling agents in the oral compositions of the present invendon are represented by the formula:
H0(C2H4O)b(C3H60)b(C2H40)bH
25 wherein a is an integer such that the hydrophobic base represented by (C3H40) has a moleeular weight of about 2750 to 4000, b is an integer such that the hydrophilic pordon (moiety) represented by (C2H40) eonsdtutes about 70-80% by weight of the eopolymer. PluronieTM Polyols of the F (solid flake or powder) type are preferred.
30 Other useful thiekening agents include eolloidal carboxyvinyl polymers, cross-linked polycarboxylate polymers, polyvinyl pyrrolidone, and fumed silica.
The gelling agent may be present in the oral eomposition of the present invention at a eoneentradon of about 0.25 to about 40% by weight and preferably about 0.5 to about 35 30% by weight of the composition.
:. .''. : ~ :':,, :
, . : ~ - ,.. : :, 2 ~ 8 1 Illustrative of the polyethylene glycols useful as additives include polyethylene glycols known by the trademark CARBOWAXTM which are nonionic polymers of ethylene oxide having the general f~rmula:
HocH2(cH2cH2o)ncH2oH
wherein n represents the average number of oxyethylene groups. The CarbowaxTM
polyethylene glycols are designated by a number such as 400, 600, 800, etc. which represents the average molecular weight. The average molecular weight of the 10 polyethylene glycols used herein is about 200-1000, preferably 40~800 and most prefeMbly 600.
,- .
Other useful humectants include non-hydroxylated compositions such as capped polyethylene glycol, where the hydrogens on the hydroxyl groups have been replaced 15 with methyl groups. Humectants such as glycerine, sorbitol polyethylene glycol and capped polyethylene glycols may be included in the oMI composition of the present in~,rcntion at a concentration of about 10 to about 40% by weight and preferably about 15 to about 25% by weight of the composition.
. .. .
20 Surfactants such as anionic and nonionic compounds may be included in the oral compositions of the present invention to serve as a wetting, solubilizing and emulsifying agents. Particularly useful anion* surfactants include sodium lauryl sulfate, salts of '~ -dodecylbcnzcne sulfonate and sodium coconut monoglyceride sulfonatcs. A particularly uscful nonionic surfactant is a water soluble polyoxyethylene monocster of sorbitol with 25 a C10~l8 fatty acid cster of sorbitol (and sorbitol anhydrides), consisting prcdominantly of the monocster, condensed with about 10-30, preferably about 20, moles of ethyleneoxide. Thc fatty acid (aliphatic hydrocarbon-monocarboxylic acid) may besaturatcd or unsaturated, c.g. Iauric, palmitic, stearic or oleic acids. TweenTM 20 is especially prcfcrred, which is a polyoxyethylene (20) sorbitan monolaurate. Capped 30 polyalkylene oxide copolymer nonionic surfactants in which the hydrogens on the hydroxyl groups have been replaced with methyl groups are also useful in the present invendon. These types of surfactants are described in U.S. Patent No. 4,988,452 and U.S. Patent No. 4,877,544.
35 The surfactant constitutes about 0.1 to 5.0% by weight and preferably 0.5 to 3% by weight of the oral composition.
-::
- . . , . ..... , - ,. ~ . , . .. , . .,, .. , ., .. , .. - ,, . ; , - . , ~ ~ , .. ..
, ., .. "{.", ., ,.. ,,;~.,.. ,.. ".. .. ", ,.".. ,.. ,.. ., ;::, ..... . : .
-: ' 2~a3lsl ,.
A flavor ingredient may constitute about 0.5 to 5.0% by weight of the oral composition of the present invention. Suitable flavoring constituents are flavoring oils, e.g., oils of spearmint, peppermint, wintergreen, sassafras, clove, sage, eucalyptus, marjoram, 5 cinnamon, and methyl salicylate, ethyl acetate and menthol.
A sweetening material is preferably also employed as a complement to the flavoring material. Suitable sweetening agents are water soluble and include sodium saccharin, sodium cyclamate, xylitol, aspartame and the like, in concentrations of about 0.10 to 1.0% by wdght. Sodium saccharin is prefer ed.
'`"' Pyrophosphate salts having and-tartar efficacy such as a dialkali or tetra-alkali metal pyrophosphate salts such as Na4P207, K4P207, Na2K2P207, Na2H2P207 and K2H2P207, long chain polyphosphates such as sodium hexametaphosphate and cyelic phosphates such as sodium trimetaphosphate may also be ineorporated in the oral 15 compositions of the present invention preferably at a concentradon of about 0.5 to about 8.0% by wdght.
Peroxide stabilizers sueh as sequestering agents, buffers, aciduladng agents, coadng or eneapsulating agents may also be ineluded in the oral eompositions of the present 20 invention. Examples of suitable sequestering agents are salts of ethybnediaminetet~aacetic acid, diethylene triarninepentaacedc acid, phosphonates such as DEQUEST available from Monsanto Chemieal Company and azaeycloheptane 2', 2' diphosphonate. Such agents stabilize the peroxide eontaining compositions by chelating ~r;i1 r metal ions swh as Fe+3, Mn+2 and Cu+2, The agents may be incorporated in the ' ~'~
25 composidons of the present invendon at a eoneentradon of about 0.1 to about 6.0% by wdght of the eomposidon.
The eomposidon of the invendon may also be formulated into an effervescent tablet eomposidon for use in eleaning dentures. - In this embodiment the tablet would be 30 eomposed of an acidic layer containing the aeetylsalieylic acid component and an efferveseent such as sodium bicarbonate, and an allcalhe layer containing the aLI~ali metal perearbonate. Tablots of this type are diselosed in U.S. Patent 5,0S5,305.
The following Example 1 illustrates the enhaneed whitening effeet on human teeth of a 35 1% by weight aqueous peraeetie aeid solution as eompared with a 30% by weight aqueous soludon of hydrogen peroxide.
. ` .
9 21 "~
Examvle I
A Minolta CR-221 Chroma Meter was used to measure the optical properties of extracted human molars and after application of whitening agents.
S . ~
The whitening agents tested were: -1. The System - 5.5 grams of sodium percarbonate and 2.5 grams of -~ .. c aspirin were dissolved in 100 mL of water. After reacting for- 2-3 ~
minutes, 3.7 grams of citric acid were add¢d to give a solut~h with au' - ~s~ i~D
final pH of about 6.
2. 1% Peracetic acid - A solution of 1% peracetic acid in water was made -n in~
and pH adjusted to about 4 with sodium hydroxide.
1 5 . ., . ~
3. 30% Hydrogen peroxide - 30% hydrogen peroxide was used as obtain~
from the bottle. .t ' I
from the bottle. .t ' I
4. 3% Hydrogen peroxide - 30% hydrogen peroxide was diluted in water to- r~
3% and a pH of 4.9 Thc Minolta Chroma Meter has a 3mm diameter circular aperture for measuring opdcal ;*, .~ ~u properdes of small ~reas. Thcmeter provides values of the optdcal pararneters L* and b* ~ J'~
in thc CE system of color measurement. L* relatesto the overall grey scal~lightness or , ~ ~,iA'. ~ J,: ,... ..
25 darkness of thc material and b* rclates to the yellowness or blueness. Other factors bcing cqual, it is plleferred to have high values of L*, indicating lightness, and low or evcn ncgatdve values of b~, indicating absencc of.yellowness. Since no two t~th have idcntdcal optdcal properdes, the whitening perfomlance of various agents is tdsted by rnonitoring the change in L* and b~ (dL* and db~ -as a funcdon of dme and treatment.
;
Thc teeth to be bleached had been stored under refrigeration in water since extracdon.
Each tooth was suspcnded in 25 mL of thc whitening soludons at room temperature.Two teeth were used per treatment and two spots on each tooth was measured. At , regular time intervals the teeth were removed from the solutions for optical 35 measurements then replacedback into the solutdons. The results as average d~* and db*
arc shown in Table 1. - - ~ T. '~' ,; ' ~Q~
Table 1 dL*/db*
s Tirne (min) 15 30 45 60 System 2.16/-2.79 3.12/-4.18 3.19/-3 373 11/-3 85 1% PAA 2.73/-2.16 2.37/-3.07 3.87/-3 344 09/-3 19 30% H22 0.69/-1.37 1.30/-2.03 1.69/-2.772.30/-3.13 3% H22 0.66/-0.40 0.02/-0.50 0.75/-1.651.43/-2.04 These results clearly show the superiority of peracetic acid for whitening teeth and that a system for in-situ generation of peracetic acid can deliver similar performance.15 ~
Exarnple 2 illustrates the in-situ preparation of peracetic àcid from a rnixture of sodium percarbonate and acetylsalicylic acid.
., ,, . . . . . . ~ , 2~ 181 11 ' Example 2 5.5 grams of sodium percarbonate and 2.5 grams of acetylsalicylic acid were dissolved in 100 mL of water at room temperature. The amount of percarbonate and acid S employed wæ calculated to deliver a theoretical maximum peracetic acid level of 1.0%.
At regular dme intervals, 3 mL aliquots of the solution were withdrawn and the concentradon of peracetic acid (PA) was measured by standard iodometric titration.
pH measurements were also recorded as a function of dme. The rate and concentration 10 of peracedc acid formadon and solution pH are recorded in Table 2.
, . . "
The following comparative examples illustrates the rapidity of peracetic acid generation -of the composidon of the present invention as compared with a combination of sodium -percarbonate and other known peracetic acid precursors, glucose pentaacetate (GPA) 15 andtetraacetylethylenediamine~TAED).
S.S grams of sodium percarbonate and 1.2 grams of GPA were dissolved in 100 mL of 20 water at room tempcrature. Thc level of GPA was selected to also deliver the theoretical maximum peracedc acid level of 1.0%, as in Example 2. 3mL aliquots of this soludon were talcen at regular dme intervals, and peracetic acid concentra~ion and pH were measured as in Example 2. Results are recorded in Table 2.
25 CO~,PARATIVE EX~MPLE 4 5.5 grams of sodium perc;ubonate and 1.~ grams of tetraacetylethylenediamine (TAED), another known peracedc acid precursor, were dissolved in 100 mL of water at roomtemperature. The levcl of TAED was selected to deliver the theoredcal maximum 30 peracedc acid level of 1.09~o, as in Examples 2 and 3. Three (3) mL aliquots of this soludon were taken at regular dme intervals, and the peracetic acid concentradon and pH
were measured as in Exarnples 1 and 2. The results are shown in Table 2.
-`-` 21~3181 Table 2 Time (min) 00.5 1.0 2.0 5.0 10.0 20.0 40.0 5Ex2 (Aspirin) PAA conc (%) 00.64 0.88 1.01 1.02 1.01 0.97 0.91 pH 9.3 - 8.8 8.9 8.8 8.8 8.8 8.8 Ex3 (~PA) PAA conc (%) 0 0.21 0.35 0.61 0.84 0.99 1.04 1.04 pH 10.6 - 10.2 10.1 9.9 9.8 9.8 9.8 Ex 4 (TAED) PAA conc (%) 0 0.04 0.27 0.51 0.85 0.98 1.01 0.97 pH lOA - 10.1 10.0 9.8 9.8 9.8 9.8 As is evident from Table 2, the composition containing acetylsalicylic acid (aspirin) generated about 100% (1.0%) of the theoretical maximum peracedc acid within two minutes and provided a solution having a relatively mild pH of about 8.8. In contrast, 20 thc composidon containing GPA and TAED delivered only about 61% and 51%
respectivcly of the theoretical maximum peracetic acid over the same two minute time period and required a total of about ten minutes to achieve the same concentration of 1.0% as achieved by the acetylsalicylic acid-containing composidon in two minutes.
25 In addition, the comparative pH measurements demonstrate that the composidon containing acetylsalicylic acid yielded a pH consistently about one unit lower than the comparable composition containing GPA or TED.
The present invention thus provides oral compositions which generate paacetic acid 30 quickly and effectively for application to the teeth while at the same time generating pH
values in said compositions more nearly approaching the safer physiological neutral pH
of 7.
2 i ~ ~ 1 8 1 Exam~le 5 A sodium percarbonate gel composition was prepared by dispersing 0.5 grams of CarbopolTM 941 in 100 grams of glycerin. Thereafter 11 grams of sodium -S percarbonate were dispersed into the glycerin gel. ~
A stock gel was prepared by dispersing 12 grams of hydroxyethylcellulose in 388 -grams of water. Three separate activator gels were made by adding 5 grams of aspirin, 2.4 grams of GPA, or 3 grams of TAED to 100 grams of the stock gel.
5 grams of each activator gel werc mixed with 5 grams of the sodium percarbonate gel.
Aftcr ten minutes, peracedc acid concentradon in each gel was measured.
Table 3 Activator PAA conc ;
Aspirin 0.62%
GPA 0.38%
TAED 0.40%
The data in Table 3 demonstrate thc superiority of aspirin in generadng PAA in gel compositions of the typc used in oral care composidons when compared to bleach activators such as GPA and TAED commonly used to enhance the performance of 25 hydrogen peroxide bleaching systems.
3% and a pH of 4.9 Thc Minolta Chroma Meter has a 3mm diameter circular aperture for measuring opdcal ;*, .~ ~u properdes of small ~reas. Thcmeter provides values of the optdcal pararneters L* and b* ~ J'~
in thc CE system of color measurement. L* relatesto the overall grey scal~lightness or , ~ ~,iA'. ~ J,: ,... ..
25 darkness of thc material and b* rclates to the yellowness or blueness. Other factors bcing cqual, it is plleferred to have high values of L*, indicating lightness, and low or evcn ncgatdve values of b~, indicating absencc of.yellowness. Since no two t~th have idcntdcal optdcal properdes, the whitening perfomlance of various agents is tdsted by rnonitoring the change in L* and b~ (dL* and db~ -as a funcdon of dme and treatment.
;
Thc teeth to be bleached had been stored under refrigeration in water since extracdon.
Each tooth was suspcnded in 25 mL of thc whitening soludons at room temperature.Two teeth were used per treatment and two spots on each tooth was measured. At , regular time intervals the teeth were removed from the solutions for optical 35 measurements then replacedback into the solutdons. The results as average d~* and db*
arc shown in Table 1. - - ~ T. '~' ,; ' ~Q~
Table 1 dL*/db*
s Tirne (min) 15 30 45 60 System 2.16/-2.79 3.12/-4.18 3.19/-3 373 11/-3 85 1% PAA 2.73/-2.16 2.37/-3.07 3.87/-3 344 09/-3 19 30% H22 0.69/-1.37 1.30/-2.03 1.69/-2.772.30/-3.13 3% H22 0.66/-0.40 0.02/-0.50 0.75/-1.651.43/-2.04 These results clearly show the superiority of peracetic acid for whitening teeth and that a system for in-situ generation of peracetic acid can deliver similar performance.15 ~
Exarnple 2 illustrates the in-situ preparation of peracetic àcid from a rnixture of sodium percarbonate and acetylsalicylic acid.
., ,, . . . . . . ~ , 2~ 181 11 ' Example 2 5.5 grams of sodium percarbonate and 2.5 grams of acetylsalicylic acid were dissolved in 100 mL of water at room temperature. The amount of percarbonate and acid S employed wæ calculated to deliver a theoretical maximum peracetic acid level of 1.0%.
At regular dme intervals, 3 mL aliquots of the solution were withdrawn and the concentradon of peracetic acid (PA) was measured by standard iodometric titration.
pH measurements were also recorded as a function of dme. The rate and concentration 10 of peracedc acid formadon and solution pH are recorded in Table 2.
, . . "
The following comparative examples illustrates the rapidity of peracetic acid generation -of the composidon of the present invention as compared with a combination of sodium -percarbonate and other known peracetic acid precursors, glucose pentaacetate (GPA) 15 andtetraacetylethylenediamine~TAED).
S.S grams of sodium percarbonate and 1.2 grams of GPA were dissolved in 100 mL of 20 water at room tempcrature. Thc level of GPA was selected to also deliver the theoretical maximum peracedc acid level of 1.0%, as in Example 2. 3mL aliquots of this soludon were talcen at regular dme intervals, and peracetic acid concentra~ion and pH were measured as in Example 2. Results are recorded in Table 2.
25 CO~,PARATIVE EX~MPLE 4 5.5 grams of sodium perc;ubonate and 1.~ grams of tetraacetylethylenediamine (TAED), another known peracedc acid precursor, were dissolved in 100 mL of water at roomtemperature. The levcl of TAED was selected to deliver the theoredcal maximum 30 peracedc acid level of 1.09~o, as in Examples 2 and 3. Three (3) mL aliquots of this soludon were taken at regular dme intervals, and the peracetic acid concentradon and pH
were measured as in Exarnples 1 and 2. The results are shown in Table 2.
-`-` 21~3181 Table 2 Time (min) 00.5 1.0 2.0 5.0 10.0 20.0 40.0 5Ex2 (Aspirin) PAA conc (%) 00.64 0.88 1.01 1.02 1.01 0.97 0.91 pH 9.3 - 8.8 8.9 8.8 8.8 8.8 8.8 Ex3 (~PA) PAA conc (%) 0 0.21 0.35 0.61 0.84 0.99 1.04 1.04 pH 10.6 - 10.2 10.1 9.9 9.8 9.8 9.8 Ex 4 (TAED) PAA conc (%) 0 0.04 0.27 0.51 0.85 0.98 1.01 0.97 pH lOA - 10.1 10.0 9.8 9.8 9.8 9.8 As is evident from Table 2, the composition containing acetylsalicylic acid (aspirin) generated about 100% (1.0%) of the theoretical maximum peracedc acid within two minutes and provided a solution having a relatively mild pH of about 8.8. In contrast, 20 thc composidon containing GPA and TAED delivered only about 61% and 51%
respectivcly of the theoretical maximum peracetic acid over the same two minute time period and required a total of about ten minutes to achieve the same concentration of 1.0% as achieved by the acetylsalicylic acid-containing composidon in two minutes.
25 In addition, the comparative pH measurements demonstrate that the composidon containing acetylsalicylic acid yielded a pH consistently about one unit lower than the comparable composition containing GPA or TED.
The present invention thus provides oral compositions which generate paacetic acid 30 quickly and effectively for application to the teeth while at the same time generating pH
values in said compositions more nearly approaching the safer physiological neutral pH
of 7.
2 i ~ ~ 1 8 1 Exam~le 5 A sodium percarbonate gel composition was prepared by dispersing 0.5 grams of CarbopolTM 941 in 100 grams of glycerin. Thereafter 11 grams of sodium -S percarbonate were dispersed into the glycerin gel. ~
A stock gel was prepared by dispersing 12 grams of hydroxyethylcellulose in 388 -grams of water. Three separate activator gels were made by adding 5 grams of aspirin, 2.4 grams of GPA, or 3 grams of TAED to 100 grams of the stock gel.
5 grams of each activator gel werc mixed with 5 grams of the sodium percarbonate gel.
Aftcr ten minutes, peracedc acid concentradon in each gel was measured.
Table 3 Activator PAA conc ;
Aspirin 0.62%
GPA 0.38%
TAED 0.40%
The data in Table 3 demonstrate thc superiority of aspirin in generadng PAA in gel compositions of the typc used in oral care composidons when compared to bleach activators such as GPA and TAED commonly used to enhance the performance of 25 hydrogen peroxide bleaching systems.
Claims (16)
1. An oral composition for whitening teeth comprising a safe and effective whitening amount of peracetic acid dissolved or suspended in a vehicle, wherein said peracetic acid is generated in situ by combining water, acetylsalicylic acid and a water soluble alkali metal percarbonate.
2. The composition of claim 1 wherein said alkali metal percarbonate is sodium percarbonate.
3. The composition of claim 1 wherein said peracetic acid is present in said composition at a concentration of from about 0.01 to about 5.0% by weight.
4. The composition of claim 3 wherein said acetylsalicylic acid and percarbonate are present in said composition in a weight ratio of from about 4:1 to 1:4 respectively.
5. The oral composition of claim 1 wherein said vehicle is a gel.
6. An oral composition for whitening teeth containing acetylsalicylic acid and an alkali metal percarbonate.
7. The composition of claim 6 wherein said acetylsalicylic acid and said percarbonate are present in said composition at a combined concentration of from about 0.5 to about 35% by weight.
8. The composition of claim 7 wherein said acetylsalicylic acid and percarbonate are present in said composition in a respective weight ratio of from about 4:1 to about 1:4.
9. The composition of claim 8 wherein said percarbonate is sodium percarbonate.
10. The composition of claim 6 wherein said acetylsalicylic acid and said alkali metal percarbonate are present in discrete particulate form.
11. The composition of claim 6 wherein said composition is in the form of at least two separate, unmixed carrier phases, one phase containing said acetylsalicylic acid and a different phase containing said alkali metal percarbonate.
12. The composition of claim 1 wherein the pH is below 7Ø
13. The composition of claim 1 wherein the pH is about 5.0 to about 6.5.
14. A method for whitening teeth comprising applying to the teeth in the oral cavity the composition of claim 1 mixed with water.
15. A method for whitening teeth comprising applying to the teeth in the oral cavity the composition of claim 5.
16. A method for whitening teeth comprising applying to the teeth in the oral cavity the composition of claim 6 mixed with water.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US07/978,840 | 1992-11-19 | ||
| US07/978,840 US5302375A (en) | 1992-11-19 | 1992-11-19 | Oral composition having improved tooth whitening effect |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2103181A1 true CA2103181A1 (en) | 1994-05-20 |
Family
ID=25526441
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002103181A Abandoned CA2103181A1 (en) | 1992-11-19 | 1993-11-16 | Oral composition having improved tooth whitening effect |
Country Status (10)
| Country | Link |
|---|---|
| US (1) | US5302375A (en) |
| EP (1) | EP0599435B1 (en) |
| JP (1) | JP3556253B2 (en) |
| AT (1) | ATE161711T1 (en) |
| AU (1) | AU678397B2 (en) |
| BR (1) | BR9304765A (en) |
| CA (1) | CA2103181A1 (en) |
| DE (1) | DE69316170D1 (en) |
| MY (1) | MY108981A (en) |
| PH (1) | PH30114A (en) |
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| US5302374A (en) * | 1993-04-21 | 1994-04-12 | Dental Concepts Inc. | Oral hygiene system |
| AU676066B2 (en) | 1993-06-01 | 1997-02-27 | Ecolab Inc. | Thickened hard surface cleaner |
| US5856282A (en) * | 1994-12-22 | 1999-01-05 | The Procter & Gamble Company | Silicone compositions |
| US5759523A (en) * | 1994-12-22 | 1998-06-02 | The Procter & Gamble Company | Detergent compositions comprising a dimethicone copolyol |
| NL9500373A (en) * | 1995-02-24 | 1996-10-01 | Diamond White Avv | Method for preparing a combination preparation for bleaching of teeth on the one hand and for skin and mucous membrane disorders on the other and the use thereof. |
| US5648064A (en) * | 1995-07-07 | 1997-07-15 | Gaffar; Abdul | Oral compositions having accelerated tooth whitening effect |
| US5908614A (en) * | 1995-08-15 | 1999-06-01 | Montgomery; Robert Eric | Peroxidase-activating oral compositions |
| ATE232715T1 (en) | 1995-09-25 | 2003-03-15 | Robert Eric Montgomery | TOOTH WHITENING COMPOSITIONS |
| US6149211A (en) * | 1995-12-12 | 2000-11-21 | Losee; Paul | Inclusion of tooth whitening oxidation chemistries into slow releasing food products |
| US6391283B1 (en) | 1997-01-10 | 2002-05-21 | Ultradent Products, Inc. | Methods and apparatus for activating dental compositions |
| US5785527A (en) * | 1997-01-10 | 1998-07-28 | Ultradent Products, Inc. | Stable light or heat activated dental bleaching compositions |
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| IL137712A0 (en) * | 1998-02-13 | 2001-10-31 | Britesmile Inc | Light-activated tooth whitening composition and method of using same |
| US6162055A (en) * | 1998-02-13 | 2000-12-19 | Britesmile, Inc. | Light activated tooth whitening composition and method of using same |
| US20030198605A1 (en) * | 1998-02-13 | 2003-10-23 | Montgomery R. Eric | Light-activated tooth whitening composition and method of using same |
| US6110446A (en) * | 1998-10-05 | 2000-08-29 | Colgate Palmolive Company | Dual component antiplaque and tooth whitening composition |
| CA2353645C (en) * | 1998-12-03 | 2013-03-12 | Redox Chemicals, Inc. | Novel methods of protecting plants from pathogens |
| ATE238766T1 (en) | 1999-07-02 | 2003-05-15 | Procter & Gamble | COMPOSITIONS FOR RELEASE OF ORAL CARE INGREDIENTS CONTAINING ORGANOSILOXANE RESINS BY USING A REMOVABLE CARRIER STRIP |
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| LU70411A1 (en) * | 1974-06-25 | 1976-04-13 | ||
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| US5279816A (en) * | 1991-11-22 | 1994-01-18 | Colgate-Palmolive Co. | Oral composition having improved tooth whitening effect |
-
1992
- 1992-11-19 US US07/978,840 patent/US5302375A/en not_active Expired - Fee Related
-
1993
- 1993-11-10 DE DE69316170T patent/DE69316170D1/en not_active Expired - Lifetime
- 1993-11-10 AT AT93250312T patent/ATE161711T1/en not_active IP Right Cessation
- 1993-11-10 EP EP93250312A patent/EP0599435B1/en not_active Expired - Lifetime
- 1993-11-11 AU AU50645/93A patent/AU678397B2/en not_active Ceased
- 1993-11-16 CA CA002103181A patent/CA2103181A1/en not_active Abandoned
- 1993-11-17 PH PH47284A patent/PH30114A/en unknown
- 1993-11-18 MY MYPI93002422A patent/MY108981A/en unknown
- 1993-11-18 BR BR9304765A patent/BR9304765A/en not_active Application Discontinuation
- 1993-11-19 JP JP29084093A patent/JP3556253B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| US5302375A (en) | 1994-04-12 |
| PH30114A (en) | 1996-12-27 |
| AU678397B2 (en) | 1997-05-29 |
| EP0599435B1 (en) | 1998-01-07 |
| ATE161711T1 (en) | 1998-01-15 |
| DE69316170D1 (en) | 1998-02-12 |
| JP3556253B2 (en) | 2004-08-18 |
| JPH06271439A (en) | 1994-09-27 |
| MY108981A (en) | 1996-11-30 |
| AU5064593A (en) | 1994-06-02 |
| BR9304765A (en) | 1994-08-16 |
| EP0599435A1 (en) | 1994-06-01 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| FZDE | Discontinued |