Multi-phase oral composition for tooth whitening

1. A multi-phase oral composition comprising:

a) from about 0.002% to about 30%, by weight of the multi-phase oral composition, of an aqueous phase having a bleaching agent;

b) at least about 70%, by weight of the multi-phase oral composition, of a hydrophobic phase, wherein the hydrophobic phase has a cone penetration consistency value of from about 100 to about 500, as measured by ASTM D937-07;

wherein the ratio of the concentration in weight percent of bleaching agent present in the aqueous phase to the concentration in weight percent of bleaching agent present in the overall multi-phase oral composition is at least about 5;

wherein the concentration of the bleaching agent is up to about 10% by weight of the overall multi-phase oral composition;

wherein the aqueous phase is dispersed as droplets within the hydrophobic phase; and wherein the multi-phase oral composition is a water-in-oil emulsion.

2. The multi-phase oral composition according to claim 1 , wherein the ratio of the concentration in weight percent of bleaching agent present in the aqueous phase to the concentration in weight percent of bleaching agent present in the overall multi-phase oral composition is at least about 10.

3. The multi-phase oral composition according to claim 2 , wherein the ratio of the concentration in weight percent of bleaching agent present in the aqueous phase to the concentration in weight percent of bleaching agent present in the overall multi-phase oral composition is at least about 50.

4. The multi-phase oral composition according to claim 1 , wherein the concentration of the bleaching agent ranges from about 0.01% to about 5% by weight of the overall multi-phase oral composition.

5. The multi-phase oral composition according to claim 1 , wherein the cone penetration consistency value of the hydrophobic phase is from about 100 to about 300, as measured by ASTM D937-07.

6. The multi-phase oral composition according to claim 1 , wherein the drop melting point of the hydrophobic phase is from about 40° C. to about 80° C., as measured by ASTM D127-08.

7. The multi-phase oral composition according to claim 1 , wherein the two-dimensional density of droplets with a cross-sectional area larger than about 10000 square microns measured using the procedure specified herein is no more than about 20 per square centimeter.

8. The multi-phase oral composition according to claim 7 , wherein the two-dimensional density of droplets with a cross-sectional area larger than about 10000 square microns measured using the procedure specified herein is no more than about 10 per square centimeter.

9. The multi-phase oral composition according to claim 1 , wherein the standard deviation of the peroxide intensity of the multi-phase oral composition smeared onto peroxide test strips measured using the procedure specified herein is no more than about 50.

10. The multi-phase oral composition according to claim 9 , wherein the standard deviation of the peroxide intensity of the multi-phase oral composition smeared onto peroxide test strips measured using the procedure specified herein is no more than about 25.

11. The multi-phase oral composition according to claim 1 , wherein the mean peroxide intensity of the multi-phase oral composition smeared onto peroxide test strips measured using the procedure specified herein is from about 1 to about 100.

12. The multi-phase oral composition according to claim 1 , wherein the mean residual peroxide intensity of the multi-phase oral composition smeared on teeth measured using the procedure specified herein is from about 20 to about 200.

13. The multi-phase oral composition according to claim 1 , wherein the bleaching agent in the multi-phase oral composition comprises hydrogen peroxide.

14. The multi-phase oral composition according to claim 1 , wherein the hydrophobic phase comprises at least one of: mineral oil thickened with wax, mineral oil thickened with polyethylene, or petrolatum.

15. The multi-phase oral composition according to claim 1 , wherein the bleaching efficacy of the multi-phase oral composition calculated as −Δb* and measured per the clinical protocol as disclosed herein is at least about 1.5.

16. The multi-phase oral composition according to claim 1 , wherein the ratio of the bleaching efficacy of the multi-phase oral composition calculated as −Δb* and measured per the clinical protocol as disclosed herein to the weight percentage of bleaching agent present in the overall multi-phase oral composition is at least about 1.5.

17. The multi-phase oral composition according to claim 1 comprising a delivery carrier.

18. The multi-phase oral composition according to claim 17 wherein the delivery carrier is a strip.

19. The multi-phase oral composition according to claim 18 wherein the strip is a deformable strip.

20. The multi-phase oral composition according to claim 1 wherein the droplets of aqueous phase have a volume-average equivalent-diameter of from about 1 to about 1000 microns.

21. The multi-phase oral composition according to claim 20 wherein the volume-average equivalent-diameter is from about 1 to about 100 microns.

22. The multi-phase oral composition according to claim 21 wherein the volume-average equivalent-diameter is from about 1 to about 50 microns.

23. The multi-phase oral composition according to claim 1 wherein the droplets of aqueous phase have a number-average equivalent-diameter of from about 1 to about 1000 microns.

24. The multi-phase oral composition according to claim 23 wherein the number-average equivalent-diameter is from about 1 to about 100 microns.

25. The multi-phase oral composition according to claim 24 wherein the number-average equivalent-diameter is from about 1 to about 50 microns.

26. The multi-phase oral composition according to claim 1 wherein the aqueous phase comprises from about 2% to about 67%, by weight of the aqueous phase, of bleaching agent.

27. The multi-phase oral composition according to claim 26 wherein the aqueous phase comprises from about 10% to about 50%, by weight of the aqueous phase, of bleaching agent.

28. The multi-phase oral composition according to claim 27 wherein the aqueous phase comprises from about 20% to about 40%, by weight of the aqueous phase, of bleaching agent.

29. The multi-phase oral composition according to claim 28 wherein the aqueous phase comprises from about 30% to about 40%, by weight of the aqueous phase, of bleaching agent.

30. The multi-phase oral composition according to claim 1 wherein the multi-phase oral composition comprises at least about 85% of the hydrophobic phase, by weight of the multi-phase oral composition.

31. The multi-phase oral composition according to claim 1 wherein the multi-phase oral composition comprises at least about 95% of the hydrophobic phase, by weight of the multi-phase oral composition.

32. The multi-phase oral composition according to claim 1 wherein the hydrophobic phase comprises petrolatum.

33. The multi-phase oral composition according to claim 1 , wherein the multi-phase oral composition further comprises from 0% to about 0.1%, by weight of the multi-phase oral composition, of emulsifier.