Sunscreen composition

Abstract

A sunscreen composition comprising from 20 to 25 wt % zinc oxide that is not surface treated and from 24 to 25 wt % water, the sunscreen composition being in the form of an emulsion having an aqueous phase and an oil phase, the sunscreen composition being free from organic UV filters or organic UV absorbers, the sunscreen composition having an SPF rating of 50 or more, the sunscreen composition being free from silicone materials and the sunscreen composition being free of titanium dioxide.

Claims

1. A sunscreen composition comprising from 20 to 25 wt % zinc oxide that is not surface-treated and from 24 to 25 wt % water, the sunscreen composition being in the form of an emulsion having an aqueous phase and an oil phase, the sunscreen composition being free from organic UV filters or organic UV absorbers, the sunscreen composition having an SPF rating of 50 or more, the sunscreen composition being free from silicone materials and the sunscreen composition being free of titanium dioxide; wherein the oil phase is a hydrophobic phase consisting of: the zinc oxide; and one or more components selected from the group consisting of: oils, fatty acids, beeswax, phospholipids and/or glycerophospholipids, hydroxystearic acids, polyhydroxystearic acids, esters of fatty acids, polyesters of fatty acids, emulsifiers and emollients/moisturizers.

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

3. A sunscreen composition as claimed in claim 1, wherein the sunscreen composition has a zinc oxide content of from 24 to 25 wt %.

4. A sunscreen composition as claimed in claim 1, wherein the sunscreen composition has a zinc oxide content of from 24.5 wt % to 24.999 wt %.

5. A sunscreen composition as claimed in claim 1, wherein the sunscreen composition has a zinc oxide content of 24.98 wt % or 25.0 wt %.

6. A sunscreen as claimed in claim 1 wherein the sunscreen composition has water present in an amount of from 24 wt % to 24.5 wt %.

7. A sunscreen composition as claimed in claim 1, wherein the aqueous phase comprises water and one or more components that are soluble in water selected from the group consisting of glycerin (glycerol), water soluble humectants, and salts.

8. A sunscreen composition as claimed in claim 1, wherein the zinc oxide is in the form of aggregates of primary particles.

9. A sunscreen composition as claimed in claim 1, wherein the zinc oxide is present in the form of aggregates of zinc oxide particles, having an 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; wherein when the zinc oxide is used at a concentration of 50 weight % in a dispersion, it produces a transparent composition having a total visible transmittance through a path length of 20 m at a wavelength of 550 nm of at least 70%.

10. A sunscreen composition as claimed in claim 1, wherein the sunscreen composition contains no anti-inflammatory active agents.

Description

DESCRIPTION OF EMBODIMENTS

(1) 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

(2) 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.

(3) 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.

(4) 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.

(5) 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.

(6) 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.

(7) 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.

(8) The sunscreen composition was subsequently subjected to SPF testing and was found to have an SPF rating of greater than 50.

Example 2

(9) A sunscreen composition having the following composition was prepared:

(10) 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

(11) Zinc oxide was present in an amount of 25% by weight in the final product.

(12) 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

(13) 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.

(14) 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.

(15) 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.