Abstract:
A liquid oral composition for loosening and removing accumulated plaque deposits on dental surfaces which has a slightly acidic pH of about 5.0 to less than 7.0 and is stable when stored at 7°-40° C. for prolonged periods. The composition contains 0.15-0.25 wt. % sodium benzoate, 0.025-0.65 wt. % sodium lauryl sulfate and 0.005-0.015 wt. % tetrasodium pyrophosphate as active ingredients.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     N/A 
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
     N/A 
     BACKGROUND OF THE INVENTION 
     The invention is concerned with liquid oral prebrushing compositions containing sodium benzoate, sodium lauryl sulfate and small but effective amounts of tetrasodium pyrophosphate. These compositions are designed for removal of plaque from teeth before brushing with a dentifrice. Dental plaque is a problem with the teeth of most persons and consists of a microbial film which adheres firmly to dental surfaces. While it often can be removed with some difficulty by surface cleaning, it has a tendency to reform rapidly so continuous treatment is needed. 
     Plaque is particularly dangerous when formed on the teeth around the gum surface as it leads to gingivitis, periodontal disease and eventually loss of teeth and jawbone. 
     While many people can obviate most plaque problems by daily brushing and flossing combined with periodic cleaning by a dental hygienist, for some this is not sufficient. Therefore, it is desirable to have an oral composition which can be used on the teeth prior to brushing to soften and loosen the plaque so that it is more easily removed by the physical abrasion of brushing. 
     U.S. Pat. No. 5,338,538 uses a combination of pyrophosphate and sodium lauryl sulfate in a prebrushing oral formulation for softening and removal of plaque. The compositions of this patent all have a relatively high concentration of pyrophosphate salt and also operate at an alkaline pH, and tend to have a problem with clouding when stored at cooler temperatures. 
     BRIEF SUMMARY OF THE INVENTION 
     The present invention relates to a liquid oral prebrushing composition designed to loosen and remove accumulated plaque deposits, has a slightly acidic pH of about 5.0 to less than 7.0, and contains sodium benzoate, sodium lauryl sulfate and tetrasodium pyrophosphate. The composition remains clear and uniform without any indication of clouding or precipitation when stored in temperatures of 7° C. to 40° C. for prolonged periods. 
     DETAILED DESCRIPTION OF THE INVENTION 
     The invention preferably is a clear solution comprising about 6.0 to about 10.0 wt. % ethyl alcohol, about 5.0 to about 15 wt. % of a selected humectant, preferably glycerin or sorbitol, about 0.02 to about 0.075 wt. % sodium lauryl sulfate, about 0.2 to about 0.85 wt. % sodium benzoate, an acid buffer to pH at about 5.5 to about 6.5, sodium saccharin to the desired sweetness level, selected flavors, a soluble thickener which may be added at 0.001 to 0.10 wt. %, and D.&amp;C. or F.D.&amp;C. dyes, as required. Sodium fluoride can be incorporated at a safe and effective level to make the product also a post-brushing rinse. About 0.01 to about 0.05 wt. % tetrasodium pyrophosphate, with the other detergent salts, i.e., sodium benzoate and sodium lauryl sulfate, are effective in loosening and assisting in removing accumulated oral plaque when the product is rinsed over dental surfaces prior to a vigorous brushing. 
     The most effective manner of combining the foregoing ingredients to provide a clear, stable product is as follows: 
     1. All alcohol soluble ingredients; namely the solubilizers, benzoic acid, and flavors are added to and mixed into the ethyl alcohol. 
     2. A separate slurry is prepared by dissolving the sodium lauryl sulfate in a portion of the batch water, adding the soluble gum thickener and mixing until clear. 
     When clear and uniform, the selected humectant (glycerin or sorbitol solution) can be added and mixed until uniform. 
     3. The major portion of the purified water is charged into the manufacturing tank, mixing is started and the balance of the water soluble materials are added, namely, sodium benzoate, tetrasodium pyrophosphate, sodium saccharin, dyes, sodium fluoride, if desired, and the balance of the humectant. This is then mixed until uniform. The alcohol phase is next added and mixed. The gum slurry is added and, after mixing until uniform, the batch is completed with purified water, mixed and sampled for specification testing. 
    
    
     The manner of making variations of this dental rinse invention is illustrated by the following examples: 
     EXAMPLE 1 
     The following oral rinse composition was formulated: 
     
       
         
               
               
               
             
               
               
             
           
               
                   
               
             
             
               
                 A. 
                 Alcohol phase, All figures are given as w/w; 
                   
               
               
                   
                 Ethyl Alcohol (190 Proof) 
                 8.675 
               
               
                   
                 Flavors 
                 0.103 
               
               
                   
                 Solubilizers 
                 0.45 
               
               
                   
                 Benzoic acid 
                 0.02 
               
               
                 B. 
                 Gum slurry; 
               
               
                   
                 Water, purified 
                 5.0 
               
               
                   
                 Sodium lauryl sulfate 
                 0.05 
               
               
                   
                 Xanthan gum 
                 0.005 
               
               
                   
                 The Gum slurry is mixed until completely clear, 
                 1.5-15.0 
               
               
                   
                 and a glycerin solution is added. If desired, 
               
               
                   
                 sorbitol can be substituted for glycerin 
               
               
                 C. 
                 Batch; 
               
               
                   
                 Water, purified 
                 65.0 
               
               
                   
                 Glycerin/sorbitol 
                 balance 
               
               
                   
                 Sodium benzoate 
                 0.20 
               
               
                   
                 Tetrasodium pyrophosphate 
                 0.01 
               
               
                   
                 Sodium saccharin 
                 0.0035 
               
               
                   
                 F.D. &amp; C. dyes 
                 QS 
               
               
                   
                 Alcohol solution 
                 all 
               
               
                   
                 Gum slurry 
                 all 
               
               
                   
                 Water, purified 
                 QS to 100% 
               
             
          
           
               
                   
                 The result is a clear solution having a pH of 5.5/6.5 
               
               
                   
                   
               
             
          
         
       
     
     The result is a clear solution having a pH of 5.5/6.5 
     EXAMPLE II 
     Oral Rinse: 
     
       
         
               
               
             
               
               
               
               
             
               
               
             
           
               
                   
                   
               
               
                   
                 % w/w 
               
               
                   
                   
               
             
             
               
                   
               
             
          
           
               
                   
                 A. 
                 Alcohol phase; 
                   
               
               
                   
                   
                 Ethyl Alcohol (190 proof) 
                 6.1814 
               
               
                   
                   
                 Flavors 
                 0.1175 
               
               
                   
                   
                 Solubilizers 
                 0.1500 
               
               
                   
                   
                 Benzoic Acid 
                 0.0190 
               
               
                   
                 B. 
                 Water phase: 
               
               
                   
                   
                 Water, purified 
                 85.4559 
               
               
                   
                   
                 Humectant 
                 7.110 
               
               
                   
                   
                 Sodium Benzoate 
                 9.850 
               
               
                   
                   
                 Sodium Lauryl Sulfate 
                 0.050 
               
               
                   
                   
                 Tetrasodium Pyrophosphate 
                 0.050 
               
               
                   
                   
                 Soluble gum thickener 
                 0.0010 
               
               
                   
                   
                 Sodium Saccharin 
                 0.0096 
               
               
                   
                   
                 F.D. &amp; C. Dyes 
                 QS 
               
               
                   
                 C. 
                 Batch 
               
             
          
           
               
                   
                 The alcohol phase and the water phase are combined and 
               
               
                   
                 the result is a clear product at a pH of 6.5/6.95 
               
               
                   
                   
               
             
          
         
       
     
     The alcohol phase and the water phase are combined and the result is a clear product at a pH of 6.5/6.95 
     EXAMPLE III 
     Pre/post brushing dental rinse: 
     
       
         
               
               
             
               
               
               
               
             
               
               
             
           
               
                   
                   
               
               
                   
                 % wt. 
               
               
                   
                   
               
             
             
               
                   
               
             
          
           
               
                   
                   
                 Alcohol Phase: 
                   
               
               
                   
                 A. 
                 Ethyl Alcohol (190 proof) 
                 6.4837 
               
               
                   
                   
                 Flavors 
                 0.1554 
               
               
                   
                   
                 Solubilizer 
                 0.845 
               
               
                   
                   
                 Alcohol solubilized humectant 
                 7.0253 
               
               
                   
                 B. 
                 Water phase: 
               
               
                   
                   
                 Water, purified 
                 83.50 
               
               
                   
                   
                 Citric Acid 
                 0.1486 
               
               
                   
                   
                 Sodium Benzoate 
                 0.8450 
               
               
                   
                   
                 Sodium Lauryl Sulfate 
                 0.0498 
               
               
                   
                   
                 Sodium Saccharin 
                 0.0097 
               
               
                   
                   
                 Sodium Bicarbonate 
                 0.4998 
               
               
                   
                   
                 Sodium Fluoride 
                 0.0020 
               
               
                   
                   
                 F.D. &amp; C Dyes 
                 QS 
               
               
                   
                   
                 Water, purified 
                 QS 
               
               
                   
                 C. 
                 Batch 
               
             
          
           
               
                   
                 The alcohol phase and the water phase are combined and 
               
               
                   
                 the resulting product is clear and has a pH of 6.5/6.95 
               
               
                   
                   
               
             
          
         
       
     
     The alcohol phase and the water phase are combined and the resulting product is clear and has a pH of 6.5/6.95 
     The low level of pyrophosphate, namely about 0.01% P 2 O 7   −4  reduces the cloudiness of the product at lower temperatures, i.e., 10° C. 
     The combination of sodium benzoate, P 2 O 7   −4  and sodium lauryl sulfate is an effective active ingredient combination which reduces the amount of active ingredients that are needed, and thus tends to eliminate the cloudiness problem in such compositions, particularly when used at a acidic composition of pH about 6.0 to below 7.0. The tetrasodium pyrophosphate is present in an amount of 0.005 to 0.015 wt. %. The sodium lauryl sulfate is present in an amount of about 0.025 to about 0.065 wt. % and sodium benzoate is present in an amount of about 0.15 to about 0.25wt. %. Adding about 0.01% to about 0.05 wt. % benzoic acid produces a buffered pH system in combination with sodium benzoate to produce a finished product having a pH of about 5.5 to about 6.5, and thus a stable product which remains stable on prolonged storage, even at low temperatures 
     The prebrushing composition of the invention may include a humectant to give a moist feel to the mouth. Certain humectants can also impart sweetness to the prebrushing composition. The humectant generally is present in an amount ranging from about 5 to about 25 wt. % of the prebrushing composition. Suitable humectants which may be used include edible polyhydric alcohols, such as sorbitol or glycerol. 
     The prebrushing composition of the invention may, in addition, include ingredients effective to provide flavoring and coloring. The flavorant may be a flavoring oil, such as, oil of peppermint, spearmint, wintergreen, eucalyptus, lemon, and orange, and sweetening agents such as sucrose, lactose, maltose, saccharine, sodium cyclamate, etc. The amount of flavoring or sweetening agent generally ranges from about 0.002% to about 0.3% of the prebrushing composition. 
     The prebrushing composition is used in a conventional manner by applying a comfortable amount, such as one tablespoon, in the mouth, and rinsing it about the dental surfaces. A reduction of the amount of plaque on dental surfaces is accomplished when the prebrushing composition of the invention is employed in conjunction with a conventional tooth brushing regimen. 
     In view of the above, it will be seen that the several objects and advantages of the present invention have been achieved and other advantageous results have been obtained. 
     As various changes could be made in the above constructions without departing from the scope of the invention, it is intended that all matter contained in the above description or shall be interpreted as illustrative and not in a limiting sense.