WO2020118369A1

WO2020118369A1 - Sunscreen composition

Info

Publication number: WO2020118369A1
Application number: PCT/AU2019/051365
Authority: WO
Inventors: Mark Chandler
Original assignee: Advance NanoTek Ltd.
Priority date: 2018-12-12
Filing date: 2019-12-12
Publication date: 2020-06-18

Abstract

A sunscreen composition comprising from 20 to 28% zinc oxide, and from 15 to 25% water, the sunscreen composition being in the form of an emulsion containing an aqueous phase and a hydrophobic phase, the sunscreen being free from organic UV filters or organic UV absorbers, the sunscreen further including a whitening agent in an amount of up to 7.5%.

Description

TITLE

Sunscreen composition TECHNICAL FIELD

[0001] The present invention relates to a sunscreen composition.

BACKGROUND ART

[0002] As awareness increases of the risks associated with overexposure to the sun causing skin damage and skin cancer, sunscreens have become very widely used. Sunscreens are applied to the skin and desirably reflect and/or block UVA and UVB rays to prevent sunburn and skin damage. Many sunscreens include components such as organic chemical compounds that absorb UV light (such as octylmethoxy cinnamate and/or octocrylene and avobenzone), inorganic compounds that absorb or reflect UV light (such as zinc oxide or titanium dioxide) and creams or carriers that enable the sunscreen to be easily and comfortably applied to the skin.

[0003] The effectiveness of sunscreens is typically measured using an SPF (sun protection factor) rating. The SPF rating is a measure of the fraction of sunburn producing UV rays that red skin. For example, "SPF 15" means that 1/15* of the burning radiation will reach the skin, assuming that the sunscreen is applied evenly at a dosage of 2 mg/cm². A user can determine the effectiveness of the sunscreen by multiplying the SPF factor by the length of time it takes for him or her to suffer sunburn without sunscreen. Therefore, if a person develops sunburn in 10 minutes without wearing a sunscreen, the same person exposed to the same intensity of sunlight will avoid sunburn for 150 minutes if wearing sunscreen with an SPF of 15. However, SPF rating is considered to be an imperfect measurement of the degree of protection provided by a sunscreen. Consequently, most countries prescribe a maximum SPF rating that can be attributed to any sunscreen. For example, in Australia, the maximum SPF rating that can be attributed to any sunscreen is SPF 50+.

[0004] Most sunscreens having an SPF rating of 50+ use organic UV filters and/or non mineral UV filters. Mineral sunscreen products that are free from non-mineral UV filters of comparable SPF rating generally use silicone film forming ingredients. They also tend to use a mixture of zinc oxide and titanium dioxide as the mineral UV filters. They also sometimes use anti-inflammatory factors, such as bisabolol, to increase the in-vivo SPF test results of a sunscreen by delaying the reddening of the skin. [0005] Some sunscreen products are sold as "all natural products", which typically means they are free from silicones and petrochemicals. The "all natural" sunscreen products that have SPF 50+ are generally anhydrous products (which contain no water) and are typically described as sunscreen butters or sunscreen balms. These products have a very thick consistency and some consumers resist using these products because they can be difficult to apply to the skin. This is especially so if the consumer has a significant amount of hair on the skin (such as hairy arms or hairy legs), as application of these products to hairy skin requires an extended period of rubbing or spreading to have the product evenly applied.

[0006] Sunscreen compositions that include water but exclude organic UV filters or non mineral UV filters have difficulty in meeting testing requirements to achieve an SPF rating of 50+.

[0007] It will be clearly understood that, if a prior art publication is referred to herein, this reference does not constitute an admission that the publication forms part of the common general knowledge in the art in Australia or in any other country.

SUMMARY OF INVENTION

[0008] The present invention is directed to a sunscreen, which may at least partially overcome at least one of the abovementioned disadvantages or provide the consumer with a useful or commercial choice.

[0009] With the foregoing in view, the present invention in one form, resides broadly in a sunscreen composition comprising from 20 to 28% zinc oxide, and from 15 to 25% water, the sunscreen composition being in the form of an emulsion containing an aqueous phase and a hydrophobic phase, the sunscreen being free from organic UV filters or organic UV absorbers, the sunscreen further including a whitening agent in an amount of up to 7.5%.

[0010] In one embodiment, the whitening agent comprises a citrus peel extract mixed with glycerine. In one embodiment, the whitening agent comprises a citrus unshiu peel extract and glycerine. In one embodiment, the whitening agent comprises a citrus unshiu peel extract. The citrus unshiu peel extract functions as a whitening agent and also an inhibitor of melano genesis. In one embodiment, the whitening agent comprises a citrus unshiu peel extract mixed with glycerine or other carrier.

[0011] In one embodiment, the whitening agent is present in an amount of from 2.5% to 10% .

[0012] In one embodiment, the sunscreen composition in accordance with the present invention has a zinc oxide content of from 20 to 27%.

[0013] The zinc oxide that is present in the composition may be in the form of fine particles. The zinc oxide may comprise the product sold by Antaria Pty Ltd under the trade name ZinClear XP and/or Zinclear XP dispersions and/or Zinclear XP 65COCO. These products may be as described in Australian patent number 2009203996 and in international patent publication number WO 2009/089523, the entire contents of which are herein incorporated by cross- reference. The zinc oxide particles may also be the same as the zinc oxide particles used in the sunscreen composition described in Australian patent number 2003205436, the entire contents of which are herein incorporated by cross-reference.

[0014] In one embodiment, the zinc oxide comprises Zinclear XP 65COCO and ZinClear XP.

[0015] In some embodiments, the zinc oxide maybe in the form of aggregates of primary particles.

[0016] ZinClear XP comprises zinc oxide particles that are formed as aggregates of smaller particles. As described in Australian patent number 2009203996, ZinClear XP is 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 pm at 550nm of at least 70%, the powder having a number average zinc oxide aggregate size of at least 0.8 pm, wherein the aggregates are mesoporous and have a total mesopore volume of at least 0.25 cm³ per gram. High-energy milling of ZinClear XP can break up the zinc oxide aggregates to reduce the overall particle size of the aggregates. ZinClear XP comprises 99 to 100% zinc oxide.

[0017] Zinclear XP 65COCO is a mixture of zinc oxide (in the form of ZinClear XP), coco- caprylate/caprate, polygylceryl-3 polyricinoleate and isostearic acid. It is a commercially available product can be purchased from Antaria Pty Ltd. Zinclear XP 65COCO is a dispersion that includes coco-caprylate/caprate as an emollient. It has high transparency and low whiteness. Zinclear XP 65COCO contains 65% zinc oxide, 30 to 31% coco-caprylate/caprate, 3.0 3.5% P°lygyl^ceryl-3 polyricinoleate and 1 to 1.5% isostearic acid. [0018] In another embodiment, the zinc oxide comprises ZinClear XP.

[0019] In one embodiment, the sunscreen composition of the present invention is also free of titanium dioxide.

[0020] In some embodiments, the sunscreen composition of the present invention is free from silicone materials and free of materials containing silicon-containing compounds. In some embodiments, the sunscreen composition of the present invention is free from silanes or poly silanes, and free from polysiloxanes.

[0021] In one embodiment, the sunscreen composition has water present in an amount of from 15 to 25%, or from 17 to 23%, or from 18 to 22%, or from 18.5 to 21%, or from 19 to 20%, or about 19.4%.

[0022] In one embodiment, the aqueous phase comprises water and other components that are soluble in water. The aqueous phase may include glycerine (glycerol) or other water soluble humectants, and one or more salts (such as NaCl and/or Disodium EDTA). Other components may also be added to the aqueous phase, including polymers and preservatives. The components added to the aqueous phase are water soluble components.

[0023] In one embodiment, the hydrophobic phase comprises an oil phase. The oil phase may comprise one or more different compounds. Examples of compounds that may be included in the oil phase include one or more of oils, fatty acids, thickeners, beeswax, phospholipids and/or glycerophospholipids, hydroxystearic acids, polyhydroxystearic acids, esters of fatty acids, polyesters of fatty acids, emulsifiers and emollients/moisturisers.

[0024] In one embodiment, the aqueous phase comprises from 20 to 45 weight percent of the composition, or from 25 to 40 weight percent, or from 28 to 38 weight percent, or from 29 to 36 weight %, or from 30 to 35 weight percent, or from 31 to 33 weight %. In one embodiment, the oil phase comprises from 55 to 80 weight percent of the composition, or from 60 to 75 weight percent, or from 62 to 72 weight percent, or from 64 to 71 weight percent, or from 65 to 70 weight percent, or from 67 to 69 weight percent.

[0025] In one embodiment, the aqueous phase comprises water, glycerol, preservatives, maltodextrin, one or more emulsifiers and one or more salts.

[0026] In one embodiment, the hydrophobic phase comprises Zinclear XP65COCO, emollients, emulsifiers and waxes. [0027] In a second aspect, the present invention provides a method for making a sunscreen accordance with the first aspect of the present invention, the method comprising mixing components of the aqueous phase together at an elevated temperature, mixing the components of the hydrophobic phase together at an elevated temperature, mixing the aqueous phase with the hydrophobic phase under stirring and homogenising the mixture, and adding the whitening agent to the mixture.

[0028] In one embodiment, the aqueous phase components are mixed together at a temperature of from 60 to 90°C, or 60 to 80°C, or 70 to 75°C, and the hydrophobic phase components are mixed together at a temperature of from 60 to 90°C, or 60 to 80°C, or 70 to 75°C. Once the components of the hydrophobic phase are mixed together and the components of the aqueous phase are mixed together, the hydrophobic phase and the aqueous phase are combined. Suitably, the hydrophobic phase and the aqueous phase are mixed together very slowly under stirring, such as rapid propeller stirring, whilst the temperature is maintained from 60° to 90°C, or 60 to 80°C, or 70 to 75°C. This mixture may then be homogenised until glossy. The mixture may then be allowed to cool to a temperature of 50°C or below and the whitening agent is then mixed with stirring into the mixture.

[0029] The mixture is then allowed to cool to room temperature.

[0030] Any of the features described herein can be combined in any combination with any one or more of the other features described herein within the scope of the invention.

[0031] The reference to any prior art in this specification is not, and should not be taken as an acknowledgement or any form of suggestion that the prior art forms part of the common general knowledge.

DESCRIPTION OF EMBODIMENTS

[0032] 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.

[0033] In this example, a sunscreen containing 20-25% 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 and no compounds containing silicon. The sunscreen contained no anti-inflammatory active agents. [0034] In this example, components of the aqueous phase were mixed together with stirring at a temperature of about 75°C to form mixture A. Components of the hydrophobic phase were mixed together with stirring at a temperature of about 75°C to form mixture B. Mixture A and mixture B were then slowly mixed together under rapid stirring and homogenised. The resulting mixture was then cooled or allowed to cool to 50°C and the whitening agent was added with stirring.

[0035] The composition had the following composition:

0036] The resulting composition comprising excellent spreading formulation providing exemplary sun protection and a touch of whitening on application to the skin. SPF testing revealed an SPF rating of above 50.

[0037] Throughout this specification, all percentages are given as weight percentages of the overall sunscreen composition.

[0038] 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.

[0039] 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.

[0040] 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.

Claims

1. A sunscreen composition comprising from 20 to 28% zinc oxide, and from 15 to 25% water, the sunscreen composition being in the form of an emulsion containing an aqueous phase and a hydrophobic phase, the sunscreen being free from organic UV filters or organic UV absorbers, the sunscreen further including a whitening agent in an amount of up to 7.5%.

2. A sunscreen composition as claimed in claim 1 wherein the whitening agent comprises a citrus peel extract.

3. A sunscreen composition as claimed in claim 2 wherein the whitening agent comprises a citrus unshiu peel extract and glycerine.

4. A sunscreen composition as claimed in any one of the preceding claims wherein the whitening agent is present in an amount of from 2.5% to 10%.

5. A sunscreen composition as claimed in any one of the preceding claims wherein the sunscreen composition has a zinc oxide content of from 20 to 27%.

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

7. A sunscreen composition as claimed in claim 6 wherein the zinc oxide is in the form of aggregates of primary particles.

8. A sunscreen composition as claimed in claim 7 wherein the zinc oxide comprises 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 pm at 550nm of at least 70%, the powder having a number average zinc oxide aggregate size of at least 0.8 pm, wherein the aggregates are mesoporous and have a total mesopore volume of at least 0.25 cm³ per gram..

9. A sunscreen composition as claimed in any one of the preceding claims wherein the zinc oxide particles are present in a mixture of zinc oxide, coco-caprylate/caprate, polygylceryl-3 polyricinoleate and isostearic acid.

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

11. A sunscreen composition as claimed in any one of the preceding claims wherein the sunscreen composition is free from silicone materials and free of materials containing silicon- containing compounds, and free from silanes or polysilanes, and free from polysiloxanes.

12. A sunscreen composition as claimed in any one of the preceding claims wherein the sunscreen composition has water present in an amount of from 15 to 25%, or from 17 to 23%, or from 18 to 22%, or from 18.5 to 21%, or from 19 to 20%, or about 19.4%.

13. 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.

14. A sunscreen composition as claimed in claim 13 wherein the aqueous phase includes glycerine (glycerol) or other water soluble humectants, and one or more salts, and optionally polymers and preservatives.

16. A sunscreen composition as claimed in claim 14 wherein the aqueous phase comprises water, glycerol, preservatives, maltodextrin, an emulsifier and one or more salts.

17. A sunscreen composition as claimed in any one of the preceding claims wherein the hydrophobic phase comprises an oil phase.

18. A sunscreen composition as claimed in claim 17 wherein the oil phase includes one or more of oils, fatty acids, thickeners, beeswax, phospholipids and/or glycerophospholipids, hydroxystearic acids, polyhydroxystearic acids, esters of fatty acids, polyesters of fatty acids, emulsifiers and emollients/moisturisers.

19. A method for making a sunscreen accordance with any one of the preceding claims, the method comprising mixing components of the aqueous phase together at an elevated

temperature, mixing the components of the hydrophobic phase together at an elevated temperature, mixing the aqueous phase with the hydrophobic phase under stirring and homogenising the mixture, and adding the whitening agent to the mixture.

20. A method as claimed in claim 19 wherein the aqueous phase components are mixed together at a temperature of from 60 to 90°C, or 60 to 80°C, or 70 to 75°C, and the hydrophobic phase components are mixed together at a temperature of from 60 to 90°C, or 60 to 80°C, or 70 to 75°C.

21. A method as claimed in claim 19 or claim 20 wherein once the components of the hydrophobic phase are mixed together and the components of the aqueous phase are mixed together, the hydrophobic phase and the aqueous phase are mixed together very slowly under stirring whilst the temperature is maintained from 60° to 90°C, or 60 to 80°C, or 70 to 75 °C and the mixture is then homogenised until glossy, and the mixture is then allowed to cool to a temperature of 50°C or below and the whitening agent is then mixed with stirring into the mixture.