Compositions Useful For Tooth Whitening

Abstract

The present invention provides tooth whitening compositions in the form of a liquid crystal or a microemulsion that includes a tooth whitening agent in an amount effective to whiten teeth, a hydrophilic phase including water, a hydrophobic phase including at least one oil, at least one anionic, nonionic, amphoteric or zwitterionic surfactant, and a water soluble co-solvent having a Hildebrand solubility parameter above 12 (cal/cm 3 ) 1/2 , as well as methods for whitening teeth including applying the liquid crystal or microemulsion composition to the teeth for a period of time and under conditions effective to whiten the teeth.

1 . A tooth whitening composition, comprising:
 a whitening agent in an amount effective to whiten teeth,   a hydrophilic phase comprising water,   a hydrophobic phase comprising an oil,   a surfactant selected from the group consisting of anionic, nonionic, amphoteric and zwitterionic surfactants; and   a water-soluble co-solvent having a Hildebrand solubility parameter above 12 (cal/cm 3 ) 1/2 ,   
     wherein the composition is in a form selected from the group consisting of a liquid crystal and a microemulsion. 
   
   
       2 . The composition according to  claim 1  wherein the oil has a Hildebrand solubility parameter value ranging from about 5 to about 12 (cal/cm 3 ) 1/2 . 
   
   
       3 . The composition according to  claim 2  comprising from about 1% to about 50% of the whitening agent by weight of the composition, and wherein the amount of hydrophilic phase ranges from about 1% to about 80% by weight of the composition, the amount of the hydrophobic phase ranges from about 1% to less than 50% by weight of the composition, and the hydrophilic phase is in predominant weight proportion relative to the hydrophobic phase. 
   
   
       4 . The composition according to  claim 3  wherein the oil is selected from the group consisting of olive oil, coconut oil, linseed oil, corn oil, mineral oil, clove oil, isopropyl myristate and isopropyl palmitate. 
   
   
       5 . The composition according to  claim 4  wherein the co-solvent is selected from the group consisting of monohydric alcohols, polyhydric alcohols, sugars and polyols. 
   
   
       6 . The composition according to  claim 4  wherein the co-solvent is selected from the group consisting of ethanol, propanol, propylene glycol, butylene glycol, ethylene glycol, glycerine, glucose, fructose, mannose, mannitol, malitol, lactitol and inositol. 
   
   
       7 . The composition of  claim 6  wherein the whitening agent comprises a peroxide in an amount of from about 1% to about 35% by weight of the composition. 
   
   
       8 . The composition of  claim 1  wherein the weight ratio of the hydrophilic phase to the hydrophobic phase ranges from about 1.5:1 to about 10:1. 
   
   
       9 . The composition of  claim 3  wherein the weight ratio of the hydrophilic phase to the hydrophobic phase ranges from about 1.5:1 to about 10:1. 
   
   
       10 . A method for whitening teeth comprising applying a composition to the teeth for a period of time and under conditions effective to whiten the teeth, the composition comprising,
 a whitening agent in an amount effective to whiten teeth, a hydrophilic phase comprising water,   a hydrophobic phase comprising an oil,   a surfactant selected from the group consisting of anionic, nonionic, amphoteric and zwitterionic surfactants; and   a water-soluble co-solvent having a Hildebrand solubility parameter above 12 (cal/cm 3 ) 1/2 ,   
     wherein the composition is in a form selected from the group consisting of a liquid crystal and a microemulsion. 
   
   
       11 . The method according to  claim 10  wherein the oil has a Hildebrand solubility parameter value ranging from about 5 to about 12 (cal/cm 3 ) 1/2 . 
   
   
       12 . The method according to  claim 11  wherein the composition comprises from about 1% to about 50% of the whitening agent by weight of the composition, and wherein the amount of hydrophilic phase ranges from about 1% to about 80% by weight of the composition, the amount of the hydrophobic phase ranges from about 1% to less than 50% by weight of the composition, and the hydrophilic phase is in predominant weight proportion relative to the hydrophobic phase. 
   
   
       13 . The method according to  claim 12  wherein the oil is selected from the group consisting of olive oil, coconut oil, linseed oil, corn oil, mineral oil, clove oil, isopropyl myristate and isopropyl palmitate. 
   
   
       14 . The method according to  claim 13  wherein the co-solvent is selected from the group consisting of monohydric alcohols, polyhydric alcohols, sugars and polyols. 
   
   
       15 . The method according to  claim 13  wherein the co-solvent is selected from the group consisting of ethanol, propanol, propylene glycol, butylene glycol, ethylene glycol, glycerine, glucose, fructose, mannose, mannitol, malitol, lactitol and inositol. 
   
   
       16 . The method of  claim 15  wherein the whitening agent comprises a peroxide in an amount of from about 1% to about 35% by weight of the composition. 
   
   
       17 . The method of  claim 10  wherein the period of time ranges from about 2 minutes to about 24 hours. 
   
   
       18 . The method of  claim 17  comprising repeated application of the composition at predetermined time intervals. 
   
   
       19 . The method of  claim 10  wherein the weight ratio of the hydrophilic phase to the hydrophobic phase ranges from about 1.5:1 to about 10:1. 
   
   
       20 . The method of  claim 12  wherein the weight ratio of the hydrophilic phase to the hydrophobic phase ranges from about 1.5:1 to about 10:1.