SUNSCREEN COMPOSITION

Abstract

A sunscreen composition includes from 20 to 25% zinc oxide, and from 24 to 31% water. The sunscreen composition is in the form of an emulsion containing an aqueous phase and an oil phase, and is free from organic UV filters or organic UV absorbers. In particular, the sunscreen composition is free from silicone materials and titanium dioxide. The sunscreen has an SPF rating of 50 more,

Claims

1. A sunscreen composition comprising from 20 to 25% zinc oxide, and from 24 to 31% water, the sunscreen composition being in the form of an emulsion containing an aqueous phase and an oil phase, the sunscreen being free from organic UV filters or organic UV absorbers, the sunscreen having an SPF rating of 50 more.

2. A sunscreen composition comprising from 20 to 25% zinc oxide, and from 24 to 31% water, the sunscreen composition including a hydrophobic phase, the sunscreen composition being in the form of an emulsion containing an aqueous phase and an organic oil phase, the sunscreen being free from organic UV filters or organic UV absorbers, the sunscreen having an SPF rating of 50 more.

3. A sunscreen composition as claimed in claim 1 or claim 2 wherein the sunscreen composition has a zinc oxide content of from 22 to 25%.

4. A sunscreen composition as claimed in claim 1 or claim 2 wherein the sunscreen composition has a zinc oxide content of from 23 to 25%.

5. A sunscreen composition as claimed in claim 1 or claim 2 wherein the sunscreen composition has a zinc oxide content of from 24 to 25%.

6. A sunscreen composition as claimed in claim 1 or claim 2 wherein the sunscreen composition has a zinc oxide content of from 24.5% to 24.999%.

7. A sunscreen composition as claimed in claim 1 or claim 2 wherein the sunscreen composition has a zinc oxide content of from 24.5% to 24.998%.

8. A sunscreen composition as claimed in claim 1 or claim 2 wherein the sunscreen composition has a zinc oxide content of about 24.98% or about 25.0%.

9. A sunscreen composition as claimed in any one of the preceding claims wherein the sunscreen composition has water present in an amount of from 26 to 31%.

10. A sunscreen composition as claimed in claim 9 wherein the sunscreen composition has water present in an amount of from 27 to 31%.

11. A sunscreen composition as claimed in claim 9 wherein the sunscreen composition has water present in an amount of from 28 to 31%.

12. A sunscreen composition as claimed in claim 9 wherein the sunscreen composition has water present in an amount of from 29 to 31%.

13. A sunscreen composition as claimed in claim 9 wherein the sunscreen composition has water present in an amount of from 29.5 to 30.6%.

14. A sunscreen composition as claimed in claim 9 wherein the sunscreen composition has water present in an amount of from 29.5 to 30.6%.

15. A sunscreen composition as claimed in claim 9 wherein the sunscreen composition has water present in an amount of between 30.48 and 30.514%.

16. A sunscreen as claimed in any one of claims 1 to 8 wherein the sunscreen composition has water present in an amount of between from 24% to 25%,

17. A sunscreen as claimed in claim 16 wherein the sunscreen composition has water present in an amount of from 24% to 24.5%.

18. A sunscreen as claimed in claim 16 wherein the sunscreen composition has water present in an amount of about 24.4%.

19. A sunscreen composition as claimed in any one of the preceding claims wherein the sunscreen composition is free from silicone materials.

20. A sunscreen composition as claimed in any one of the preceding claims wherein the aqueous phase comprises water and other components that are soluble in water selected from one or more of glycerin (glycerol), water soluble humectants, and one or more salts

21. A sunscreen composition as claimed in any one of the preceding claims wherein the sunscreen composition includes a hydrophobic phase comprising an oil phase including one or more oils, fatty acids, beeswax, phospholipids and/or glycerophospholipids, hydroxystearic acids, polyhydroxystearic acids, esters of fatty acids, polyesters of fatty acids, emulsifiers and emollients/moisturisers.

22. A sunscreen composition as claimed in any one of the preceding claims wherein the zinc oxide that is present in the composition are in the form of fine particles.

23. A sunscreen composition as claimed in any one of the preceding claims wherein the zinc oxide is in the form of aggregates of primary particles.

24. A sunscreen composition as claimed in any one of the preceding claims wherein the zinc oxide particles comprise zinc oxide particles that are formed as aggregates of smaller particles, the zinc oxide particles comprising a zinc oxide powder comprising zinc oxide agglomerates which, when used in a dispersion at a concentration of 50 weight % of zinc oxide, produces a transparent composition having a total visible transmittance through a path length of 20 m at 550 nm of at least 70%, the powder having a number average zinc oxide aggregate size of at least 0.8 m, wherein the aggregates are mesoporous and have a total mesopore volume of at least 0.25 cm.sup.3 per gram.

25. A sunscreen composition as claimed in any one of the preceding claims wherein the zinc oxide is provided as a mixture of zinc oxide particles, coco-caprylate/caprate, polygylceryl-3 polyricinoleate and isostearic acid, the mixture containing 65% zinc oxide, 30 to 31% coco-caprylate/caprate, 3.0 3.5% polygylceryl-3 polyricinoleate and 1 to 1.5% isostearic acid.

26. A sunscreen composition as claimed in any one of the preceding claims wherein the sunscreen composition is free of titanium dioxide.

27. A sunscreen composition as claimed in any one of the preceding claims wherein the sunscreen composition contains no anti-inflammatory active agents.

28. A method for producing a sunscreen composition as claimed in any one of the preceding claims, the method comprising the steps of forming an oil phase, adding zinc oxide particles to the oil phase, preparing an aqueous phase, and mixing the aqueous phase with the mixture of the zinc oxide particles and the oil phase under high shear mixing, wherein the zinc oxide particles comprise aggregates of zinc oxide and the high shear mixing breaks up the zinc oxide aggregates into smaller particles.

29. A method as claimed in claim 2285 wherein the high shear mixing breaks up the zinc oxide aggregates into smaller particles but does not break up a significant number of the zinc oxide aggregates into primary nanoparticles.

30. A method as claimed in claim 29 wherein less than 10% of the zinc oxide aggregates are broken up into primary nanoparticles, or less than 5% of the zinc oxide aggregates are broken up into primary nanoparticles, or less than 3% of the zinc oxide aggregates are broken up into primary nanoparticles, or less than 2% of the zinc oxide aggregates are broken up into primary nanoparticles, or less than 1% of the zinc oxide aggregates are broken up into primary nanoparticles.

31. A method as claimed in any one of claims 28 to 30 wherein the oil phase is prepared by mixing the ingredients of the oil phase and heating to an elevated temperature with uniform stirring or until all solids have completely dissolved, the oil phase being heated to a temperature of up to 90 C., or to 80 C., or up to 75 C., or about 75 C., in this step.

32. A method as claimed in any one of claims 28 to 31 wherein the zinc oxide particles are added to the oil phase once the oil phase has been formed, the zinc oxide particles being added under stirring and at elevated temperature.

33. A method as claimed in any one of claims 28 to 32 wherein the aqueous phase is prepared by combining water with all other ingredients of the aqueous phase and stirring, this step being conducted at elevated temperature of up to 90 C., or to 80 C., or up to 75 C., or about 75 C.

34. A method as claimed in claim 33 wherein the aqueous phase is then be mixed with a mixture of zinc oxide particles and the oil phase and mixed under high speed stirring.

35. A method as claimed in claim 34 wherein the mixture of the oil phase and the zinc oxide particles are mixed under high speed stirring and the aqueous phase is added to the mixture of the zinc oxide particles in the oil phase.

36. A method as claimed in claim 34 or claim 35 wherein the composition is subjected to high shear stirring.

37. A method as claimed in claim 36 wherein the composition is cooled to 25 to 30 C. and then subjected to high shear stirring for a period of less than 5 minutes, or for a period of less than 4 minutes, or for a period of less then 3 minutes, or for a period of less then 2 minutes, or for about 1 minute.

Description

DESCRIPTION OF EMBODIMENTS

[0037] The following example has been provided to illustrate a preferred embodiment of the present invention. Therefore, it will be understood that the present invention should not be considered to be limited solely to the features as shown in the following example.

Example 1

[0038] In this example, a sunscreen containing 24.998% zinc oxide by weight was produced. The sunscreen contained no organic UV filters. The sunscreen contained no non-mineral organic filters. The sunscreen contained no silicone components. The sunscreen contained no anti-inflammatory active agents.

[0039] The zinc oxide was added to the product in two forms, being ZinClear XP 65 COCO and as the pure zinc oxide powder Zinclear XP. ZinClear XP 65 COCO comprises a dispersion of zinc oxide powder that has been formed using a high energy bead milling technique.

[0040] In this example, an oil phase was formed by mixing oil, fatty acids, waxes, emulsifiers, emollients/surfactants, and skin conditioning agents, in a mixing tank. The ingredients were gently heated to 75 C. with uniform stirring until all solids had completely dissolved. The zinc oxide particles were then mixed into the oil phase and temperature returned to 75 C. with stirring until uniform. The mixture of zinc oxide and the oil phase comprised from 67% to 68%, by weight, of the total sunscreen composition.

[0041] An aqueous phase comprising water, glycerin, sodium chloride and a polysaccharide was prepared by combining the ingredients in a container and heating to 75 C. with stirring. Water was present in an amount such that the water content of the final sunscreen composition was between 30.48 and 30.514% by weight.

[0042] The mixture of the oil phase in zinc oxide was then maintained at 75 C. and subjected to fast propeller stirring whilst the aqueous phase was gradually added at 75 C. Fast propeller stirring was maintained during addition of the aqueous phase. This stirring is not expected to affect the particle size of the zinc oxide aggregates, although testing has not yet confirmed this.

[0043] The resulting mixture was cooled to 25 to 30 C. with gentle stirring and then homogenised under high shear stirring for 1 minute to achieve the final viscosity of the emulsion. The high shear stirring resulted in the breakdown of the zinc oxide aggregates to smaller aggregates. The inventors believe that the high shear stirring will break the zinc oxide aggregates down into smaller mesoporous aggregates, but is unlikely to result in the zinc oxide aggregates being reduced to their primary particles.

[0044] The sunscreen composition was subsequently subjected to SPF testing and was found to have an SPF rating of greater than 50.

Example 2

[0045] A sunscreen composition having the following composition was prepared:

TABLE-US-00001 wt % in final Phase (%) Ingredient Function A 24.4 Water A 10.0 Glycerin Humectant A 0.3 Mixture of phenylpropanol, Preservative propanediol, capryl glycol and tocopherol A 0.7 Caprylyl glycol and ethy; Preservative hexylglycerin A 1.0 Maltodextrin Polymer A 0.5 Cetyl phosphate Emulsifier A 0.5 Sodium cgloride Salt A 0.1 EDTA Salt B 40% Mixture of zinc oxide nanoparticles, Active coco-caprylate/caprate and polyglyceryl- sunscreen 3 polyricinoleate and isostearic acid B 7.0 C15-C19 Alkane Emollient B 5.5 Jojoba seed oil Emollient B 5.0 Polyglycerul - 3 Emollient polyricioleate B 4.0 Yellow Beeswax Wax B 1.0 Polyhydroxystearic acid Dispersant

[0046] Zinc oxide was present in an amount of 25% by weight in the final product.

[0047] The product was made by mixing and heating the ingredients of phase A to 75 C., sequentially mixing and heating the ingredients of phase B to 75 C., maintaining he on both faces and stirring until uniform, adding phase B to phase A slowly with propeller stirring, and homogenising until glossy, if needed. The product had an SPF rating of greater than 50

[0048] In the present specification and claims (if any), the word comprising and its derivatives including comprises and comprise include each of the stated integers but does not exclude the inclusion of one or more further integers.

[0049] Reference throughout this specification to one embodiment or an embodiment means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, the appearance of the phrases in one embodiment or in an embodiment in various places throughout this specification are not necessarily all referring to the same embodiment. Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more combinations.

[0050] In compliance with the statute, the invention has been described in language more or less specific to structural or methodical features. It is to be understood that the invention is not limited to specific features shown or described since the means herein described comprises preferred forms of putting the invention into effect. The invention is, therefore, claimed in any of its forms or modifications within the proper scope of the appended claims (if any) appropriately interpreted by those skilled in the art.