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
  • A61K8/72—Cosmetics or similar toiletry preparations characterised by the composition containing organic macromolecular compounds
  • A61K8/90—Block copolymers
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
  • A61K8/00—Cosmetics or similar toiletry preparations
  • A61K8/02—Cosmetics or similar toiletry preparations characterised by special physical form
• • 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
  • A61K8/19—Cosmetics or similar toiletry preparations characterised by the composition containing inorganic ingredients
  • A61K8/22—Peroxides; Oxygen; Ozone
• • 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

Definitions

• This invention relates to dental whitening or brightening compositions having viscosities capable of responding to a change in temperature.
• the invention also relates to methods of whitening or brightening teeth surfaces using the composition, particularly methods of whitening or brightening teeth by dispensing the composition into a dental tray or directly onto tooth surfaces and keeping it in the mouth for some period of time.
• a user is provided with a dental tray, either by a dental practitioner or as part of a purchased dental whitening kit.
• the tray is intended to retain the whitening composition at the desired location(s) and maintain contact between the tooth surface and the whitening composition.
• the dental tray is typically custom fitted to the user's personal dentition.
• Some dental practitioners may choose to have selectively enlarged tooth-treating compartments or reservoirs fabricated within the dental tray which are adapted to receive a sufficient amount of tooth whitening composition.
• the purpose for having such reservoirs is to provide more whitening composition and to ensure, if desired, long-lasting exposure of the teeth to the whitening agent.
• the dental tray loaded with whitening composition is typically worn by the patient for some extended period of time (e.g. 30 minutes to 8 hours), depending on the degree of discoloration the user desires to remove. This treatment is repeated over a sufficient period of time to effect the tooth whitening and bleaching process.
• Whitening compositions are generally formulated with thickening rheological modifiers such as carboxypolymethylene, cellulosic polymers, or fumed silicas in order for the compositions to be provided as a thickened composition.
• thickening rheological modifiers such as carboxypolymethylene, cellulosic polymers, or fumed silicas
• Pellico, U.S. Patent No. 5,361,000 is directed to dental whitening compositions thickened with glycerin and carboxypolymethylene.
• Pellico, U.S. Patent No. 5,718,886 discloses a stabilized anhydrous dental whitening composition utilizing Xanthum gum as a thickening agent.
• a system can increase from ambient temperature of about 22-25°C, to about 37°C.
• the whitening composition may have a tendency to decrease in viscosity and become more flowable.
• the composition may also become diluted from saliva moving in and out of the tray, resulting in dilution of the composition. This thinning and viscosity decrease creates a tendency for the composition and thus the whitening agent, to flow out of the tray, resulting in a reduced amount of whitening composition available for treatment at the target location for the desired length of time.
• the invention provides a dental whitening composition whose viscosity is responsive to temperature changes, wherein the viscosity increases with an increase in temperature. These compositions also preferably have the ability to reverse their viscosity upon the lowering of temperature.
• the compositions of the invention comprise a whitening agent and a thermally responsive modifier.
• compositions of the invention work very well in the oral environment where temperature is generally higher than ambient or the pre-treatment temperature of a composition. This differential in temperature thickens the composition and thus provides a thickened, semi-solid or gel-like composition in the oral environment.
• a preferred method of use of the invention comprises dispensing the composition into a dental tray that is subsequently placed into a user's mouth. Upon exposure of the composition to the oral temperature, the composition thickens to a semi-solid or gel-like state. Alternatively, the composition can be dispensed into a pre-warmed tray such that the composition thickens upon its contact with the tray.
• Fig. 1 is a graphic illustration of the viscosity versus temperature data as described in Example 3.
• compositions and methods of the present invention provide easy delivery of tooth whitening compositions, especially with those compositions that are initially a low viscosity liquid at its pre-treatment temperature. These compositions can be dispensed from delivery devices that have small orifices, require less force to dispense and become thicker or more viscous only upon being exposed to the temperature of the oral environment.
• compositions of this invention are particularly suitable for use in the intraoral environment where a composition haying a pre-treatment temperature at or lower than ambient (room temperature) is applied to a user's tooth surfaces that is near or at oral temperature of about 30°C - 39°C.
• room temperature ambient
• the composition be thermally reversible.
• the composition not only has the ability to increase its viscosity at an elevated intra-oral temperature, but also reverses or decreases its viscosity upon a decrease in temperature.
• the capacity of the dental composition to thicken at human body temperatures is a critical feature of the invention, for it is in this property that many of the disadvantages of previous approaches are overcome.
• the dissipative characteristic of liquid solutions is avoided since the compositions herein experience thickening at the site of treatment.
• the problems of formulation, handling, delivery and application of viscous compositions are overcome since the present compositions may be free-flowing liquids prior to treatment.
• a “semi-solid,” as used herein, is a material whose physical state is between a liquid and solid state, pure or mixed solvent or solution entrained within a network, and can be alternatively be considered as a gel.
• pure or mixed solvent and/or solution as stated herein, it is recognized that a mixture of solvents may be absorbed by the network. Additionally, the solvent may include salts or other additives so as to form a solution, which may also be absorbed or entrained within the network.
• Thickening is where a composition undergoes a substantial increase in the viscosity of the composition.
• the degree of thickening is dependent on the initial viscosity of the composition.
• the initial viscosity of the composition may be low enough such that the composition is in a liquid state.
• the viscosity increases to result in a thickened composition.
• a viscosity increase in the range of about 10- to about 100-fold can be experienced when the initial viscosity is low enough such that the composition is a liquid.
• a composition in a liquid state may have a viscosity of about 0 to about 7000 poise.
• the viscosity of the composition can increase to at least about 10,000 poise.
• the composition preferably has the ability to reverse its viscosity and return to flow properties of a liquid.
• Yet another preferred embodiment of the invention is when the initial viscosity of the composition is at a level at which the composition is in a semi-solid or gelatinous state at pre-treatment temperature, and upon exposure to a higher treatment temperature, the composition transforms into an "ultra-thick" or "ultra-gel” composition or one with a substantially higher viscosity and very low flow characteristics.
• These compositions typically have an initial viscosity of no less than about 7000 poise, which then thicken about 2- to about 5-fold.
• the pre-treatment temperature is the temperature at which the composition is subjected to prior to application or treatment.
• the range for the pre-treatment temperature can be about 5°C to about 29°C, although there may be certain instances where the temperature may be outside this range. Having a pre-treatment temperature at about 20°C to 25°C allows the composition to be easily stored at ambient or room temperature. Alternatively, the compositions of the invention can also be advantageously stored at lower, refrigeration pre-treatment temperatures of about 5°C to about 10°C to provide improved stability and shelf life.
• the treatment temperature is the temperature at which the composition is exposed to during intraoral application. This can be at or near body temperature, or about 30°C to about 39°C.
• the dental composition consists of a water- miscible, physiologically compatible medium which is a liquid or gel at ambient temperature below about 30°C and experiences thickening at oral temperatures above about 30°C. It has been found that a composition having a thickening transition temperature in the range of from about 25°C to about 40°C is useful in the practice of the present invention. Preferably, the thickening occurs in a temperature range of from about 25°C to about 39°C, and more preferably from about 30° to about 35°C.
• compositions of this invention are comprised of a solvent, a whitening agent and a thermally responsive viscosity modifier that provides the desired viscosity increase at the desired elevated temperature range.
• other adjuvants may be added to the composition.
• the composition of this invention should be physiologically compatible so that no adverse reaction occurs if the tooth whitening composition comes in contact with human tissue or fluids.
• the solvent, whitening agent, and thermally responsive viscosity modifier may be contained in one mixture or contained separately in a multiple-part system. In a multiple-part system, the whitening agent may be kept physically separate from the viscosity modifier, to be admixed just prior to treatment.
• a "thermally responsive viscosity modifier” is one or more polymeric substances that provides the composition or polymeric system the capability of substantially increasing its viscosity in response to an increase in temperature.
• Suitable polymeric substances useful as thermally responsive viscosity modifiers include polyoxyalkylene polymers, particularly the polymeric surfactants available under the tradename PLURONIC. This class of polymers is available commercially from BASF Wyandotte Corporation. Other polyoxyalkylene polymers may also be useful as a thermally-responsive composition material.
• a preferred dental composition in accordance with this invention comprises an aqueous solution of a selected poly oxyethylene-polyoxypropylene block copolymer.
• a composition comprising polyoxyethylene-polyoxypropylene block copolymers in which the number of polyoxyethylene units is at least about 50% of the number of units in the total molecule, and the block copolymer having an average molecular weight of from about 1100 to about 15,500 has been found to be particularly useful. It is more preferable that a composition comprises about 70% polyoxyethylene units of the total number of monomeric units in the copolymer and the copolymer has an average molecular weight of about 11,500.
• PLURONIC F-127 is a material that meets these criteria.
• the PLURONIC polymers are closely related block copolymers that may be generically classified as polyoxypropylene-polyoxyethylene condensates that terminate in primary hydroxyl groups. These polymers are formed by the condensation of propylene oxide into a propylene glycol nucleus followed by the condensation of ethylene oxide onto both ends of the polyoxypropylene base. The polyoxyethylene hydrophilic groups on the ends of the base pre-polymer are controlled in length to constitute from about 10% to about 80% by weight of the final polymer.
• the PLURONIC polymer series of products may be represented empirically by the formula: HOfC 2 H ⁇ O ⁇ C 3 H 6 O ft ( H / O c H where a and c are statistically equal.
• the concentration of the block copolymers is an important parameter and can be formulated in such a manner corresponding to the other components' concentrations.
• concentration of the copolymer By adjusting the concentration of the copolymer to accommodate other solutes present in the composition, any desired liquid to semi-solid transition temperature in the critical range of above ambient temperature and below body temperature can be achieved.
• the principal consideration is the selection of a concentration which, in conjunction with all of the constituents of the composition, will provide a liquid to semi-solid transition or alternatively, a gel to "ultra-gel" transition temperature in the required range.
• a useful block copolymer concentration is from about 5% to about 40% by weight (wt. %) of the composition, preferably from about 15 wt. % to about 26 wt. % of the composition. Excellent results have been obtained using aqueous solutions having from about 17 wt. % to about 26 wt. % of PLURONIC F-127.
• Another known system which is liquid at room temperature, but forms a semi-solid when warmed to about body temperature is formed from tetrafunctional block polymers of polyoxyethylene and polyoxypropylene condensed with ethylenediamine, commercially available under the tradename TETRONIC polymer (BASF Wyandotte Corp.). These compositions are formed from approximately 10% to 50% by weight of the polymer in an aqueous medium. See, for example, U.S. Patent No. 5,252,318 which is incorporated by reference herein.
• Particularly preferred polymers for compositions of the invention are the PLURONIC F-127 and F-108 and the class of TETRONIC polymers.
• These viscosity modifiers are block copolymers of ethylene oxide and propylene oxide. Thickening tendencies of block copolymers increase as ethylene oxide content and total molecular weight increase.
• Thermally responsive block copolymers have been disclosed in U.S. Patent Nos. 4,474,751; 4,474,752; 5,441,732; and 5,252,318, as well as the Product Catalog, "BASF Performance Chemicals," all the teachings of which are incorporated by reference herein. These block copolymers offer extremely low toxicity and a high degree of mildness for applications involving human contact.
• a preferred solvent for the composition of this invention is water.
• the concentration of water in the composition can be in the range of from about 30 wt.% to about 90 wt. % of the composition, and is preferably from about 50 wt. % to about 80 wt. %. More preferably, water can exist in the range of about 50 wt. % to about 75 wt. % of the composition.
• the water used in forming the aqueous solution is preferably purified, as by distillation, filtration, ion-exchange or the like.
• solvents may be used, including anhydrous solutions comprising a polyol component such as propylene glycol ⁇ r polyethylene glycol.
• Propylene glycol may be present in the composition in an amount from about 10 wt. % to about 55 wt. % of the composition.
• Polyethylene glycol may be used in the practice of this invention, having a molecular weight from about 400 to about 1500 and may be in an amount from about 10 wt. % to about 50 wt. % of the composition.
• Glycerin may also be used as a constituent of the composition.
• the whitening agent used in the present invention may be any material that has the effect of whitening teeth.
• Whitening agents are preferably selected from hydrogen peroxide and its urea complex: carbamide peroxide (CO(NH 2 ) 2 H 2 O ). These whitening agents are also known by alternative names, including urea hydrogen peroxide, hydrogen peroxide carbamide, or perhydrol-urea. Alternatively, sodium hypochlorite may be suitable for use as the whitening agent.
• the concentration of a whitening agent in the composition can vary depending upon its reactivity. With carbamide peroxide, for example, the currently preferred concentration range is from about 3% to about 40%, with a range from about 4% to about 21% being most preferred.
• compositions for certain purposes.
• a preferred embodiment of the invention can contain fluoride, a desirable additive in oral compositions.
• Additives may also be included in the composition to promote the stability of the formulation.
• Anti-microbial agents, antifungal agents, and preservatives may be added to the composition to improve its shelf-life.
• Adhesive modifiers, which reduce or increase the stickiness of the composition may also be included in the formulation.
• the compositions may further include other adjuvants such as fillers, dyes, cariostatic agents, flavorings, sweeteners, medicaments and sodium bicarbonate.
• compositions of this invention can be employed in using various methods.
• One method of use of these whitening compositions entails application of the composition to the tooth structure directly from the composition's container or dispenser such as a bottle, syringe, or tube.
• the whitening composition can be applied by using a brush to paint it onto the tooth surface.
• the composition is kept on the user's tooth surface(s) for a desired time period to effectuate whitening. The length of time the composition is in contact with the tooth surface(s) would depend on the amount of discoloration the user prefers to remove.
• the whitening composition is loaded into a dental tray.
• dental trays can be custom fitted to a user's dentition and be made with or without reservoirs.
• a preferred reservoir is described in U.S. Patent Application 53911USA1 A, filed on August 13, 1998, entitled Medication Delivery Tray, assigned to the assignee of the present invention, the disclosure of which is incorporated herein by reference.
• Dental trays can be made from varying thicknesses and softness of pliable thermo-formable plastic materials. Typically, these materials are 0.02 - 0.08 inches thick.
• An alternative method of use incorporates a pre-warmed dental tray into which the composition is loaded. Upon contact of the composition having a pre-treatment temperature, with the tray having a higher temperature, the composition experiences thickening. This method provides easy handling of a loaded tray into a user's mouth, with minimal fear of the composition moving to an undesired section of the tray or having the composition flow out of the tray.
• the compositions are thermally reversible, the composition can be readily removed from the dentition or tray by cooling the material below the liquid to semi-solid transition temperature, thus reversing the thickening effect. This can be accomplished with cool water or other physiologically compatible liquid.
• the concentrations of the components in the whitening composition may be adjusted and diluted by adding water or other liquid solution in the oral cavity. By adjusting the concentrations of the components, the transition temperature is correspondingly adjusted, and thus provides the user the ability to remove the composition even with warm solutions. Water or other liquid solutions may be administered through a rinsing cup, squirt bottle, a liquid dispensing dental tool, or any other liquid dispensing device that can provide solution to the oral environment.
• the composition may be brushed, wiped, or blown off.
• aqueous stock solution containing approximately 15% hydrogen peroxide(H 2 O 2 ) was prepared by transferring 5 grams of a 30% H 2 O 2 (J.T. Baker) and 5 grams of distilled water to a glass vial. The stock solution was mixed thoroughly.
• aqueous stock solution containing approximately 20% urea hydrogen peroxide (carbamide peroxide) was prepared by transferring 4 grams of 97% urea hydrogen hydrogen peroxide (Sigma) and 16 grams of distilled water to a glass vial. The stock solution was mixed thoroughly. (The hydrogen peroxide content of the urea hydrogen peroxide was about 35%). Stock solution contained about 7% H 2 O 2 .
• a thermally-reversible hydrogen peroxide composition was prepared by transferring the ingredients below to a glass vial and mixing thoroughly until a colorless and transparent liquid solution was obtained.
• Stock Solution 1 1.60 grams
• the above solution contained approximately 12% hydrogen peroxide, 68% water and 20% PLURONIC F127.
• the glass vial containing the liquid peroxide solution was warmed to body temperature by holding the vial in a human hand. Following about one to two minutes, the liquid was transformed into a colorless, transparent composition that did not flow upon inverting the vial. The vial was allowed to cool to room temperature wherein the composition was transformed back to the low viscosity state. This cycle was repeated several times with the same outcome/
• the liquid and semi-solid (gel) states were both semi-quantitatively evaluated for hydrogen peroxide utilizing hydrogen peroxide analysis strips.
• the analysis utilized "EM Quant Peroxide Test Strips" (EM Science Gibbstown, New Jersey, Catalog No. 10011-1). The compositions were evaluated according to the manufacturer's directions.
• Example 2 A thermally reversible composition containing urea hydrogen peroxide was prepared by transferring the ingredients below to a glass vial and mixing thoroughly until a colorless and transparent liquid solution was obtained.
• the above solution contained approximately 16% urea hydrogen peroxide (or about 5.6% hydrogen peroxide), 64% water and 20%) PLURONIC F127.
• the glass vial containing the liquid peroxide solution was warmed to body temperature by holding the vial in a human hand. After about 1 minute, the liquid transformed to a colorless, transparent composition that did not flow upon inverting the vial. The vial was allowed to cool to room temperature wherein the semi-solid composition was transformed back to the low viscosity state. This cycle was repeated several time with the same outcome.
• liquid and semi-solid states were both semi-quantitatively evaluated for hydrogen peroxide utilizing hydrogen peroxide analysis strips, EM Quant Peroxide Test Strips (EM Science; Gibbstown, New Jersey, Catalog No. 10011-1), according to the manufacturer's directions. Both the liquid and semi-solid states indicated the presence of significant amounts of available peroxide.
• Table 1 summarizes the results of the two previous examples.
• the "+” indicates an increase in the viscosity.
• the "-” indicates a decrease in the viscosity.
• the presence of hydrogen peroxide as indicated in the table are the results obtained from the semi- quantitative test using the EM Quant Peroxide Test Strips and test method.
• compositions that have been evaluated for viscosity as a function of temperature. The compositions are described below:
• FIG. 1 illustrates that aqueous compositions containing PLURONIC F127 polymer exhibit a relatively sha ⁇ increase in viscosity upon warming from room temperature to about 45 °C.
• Sample C which exhibited semi-solid-like characteristics at room temperature (due to the inco ⁇ oration of a fumed silica) also increased substantially upon an increase in temperature.

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• 1998
  • 1998-11-12 US US09/190,541 patent/US6312666B1/en not_active Expired - Lifetime
• 1999
  • 1999-03-16 WO PCT/US1999/006146 patent/WO2000028955A1/en not_active Ceased
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