ANTI-ACNE COMPOSITION

Abstract

A composition for treating acne includes an anti-acne active agent that includes salicylic acid, an emulsifier, an emollient, particles of zinc oxide, water and a humectant. The composition has a sun protection factor (SPF) of at least 5. The zinc oxide can be included in a powder with particles that are formed as aggregates of smaller particles which, when used in a dispersion at a concentration of 50 weight % of zinc oxide, produces a transparent composition.

Claims

1. A composition for treating acne, the composition comprising an anti-acne active agent including from 0.35 to 0.65 weight percent salicylic acid, an emulsifier, an emollient, particles of zinc oxide, the particles of zinc oxide being present in an amount of from 22 to 28% by weight, water and a humectant, the composition having a sun protection factor (SPF) of at least 5.

2. A composition as claimed in claim 1 wherein the composition has an SPF of at least 15, or an SPF of 30 or an SPF of 50 or more.

3. A composition as claimed in claim 1 or claim 2 wherein the composition further includes a salt and/or a preservative.

4. A composition as claimed in any one of the preceding claims wherein the particles of zinc oxide are sized less than 1 μm.

5. A composition as claimed in any one of the preceding claims wherein the zinc oxide are in the form of aggregates of primary particles.

6. A composition as claimed in any one of the preceding claims wherein the composition comprises a powder comprising zinc oxide particles that are formed as aggregates of smaller particles 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 μm at 550 nm of at least 70%, the powder having a number average zinc oxide aggregate size of at least 0.8 μm, wherein the aggregates are mesoporous and have a total mesopore volume of at least 0.25 cm.sup.3 per gram.

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

8. A composition as claimed in any one of the preceding claims wherein the composition comprises from 23 to 27% by weight zinc oxide, or from 24 to 26% by weight zinc oxide, or about 25% by weight zinc oxide.

9. A composition as claimed in any one of the preceding claims wherein the anti-acne agent comprises salicylic acid, or the anti-acne active agent comprises salicylic acid and a Magnolia Officinalis bark extract.

10. A composition as claimed in any one of the preceding claims wherein the composition comprises of a mixture of excipients that provide humectant, preservative, salting and emollient functions, the combination of these excipients being present in an amount of from 5% to 10% by weight.

11. A composition as claimed in any one of the preceding claims wherein the emulsifier is present in an amount of from 5 to 10% by weight, or in an amount of from 6 to 9% by weight, or in an amount of from 7 to 8% by weight, or about 7.50% by weight.

12. A composition as claimed in any one of the preceding claims wherein the emollient is present in an amount of from 6 to 10% by weight, or from 7 to 9% by weight, or about 8% by weight.

13. A composition as claimed in any one of the preceding claims wherein the water is demineralised water.

14. A composition as claimed in any one of the preceding claims wherein the water is present in an amount of from 35 to 40% by weight, or from 36 to 39% by weight, or from 36 to 38% by weight, or about 37% by weight.

15. A method for preparing an anti-acne composition as claimed in any one of the preceding claims, the method comprising a) combining the anti-acne agent, the emollient and the emulsifier and mixing at an elevated temperature to obtain a homogenous mixture, b) adding the particles of zinc oxide to the mixture from step (a) and stirring to obtain a mixture, c) mixing water and the humectant and adding the water and humectant to the mixture from step (b) with stirring, and d) cooling to room temperature whilst maintaining stirring.

16. A method as claimed in claim 15 wherein step (a) is conducted a temperature of from 70° C. to 90° C., or from 80° C. to 85° C.

17. A method as claimed in claim 15 or claim 16 wherein steps (b) and (c) are conducted at the same temperature as a step (b).

18. A method as claimed in any one of claims 15 to 17 wherein salt and preservative are mixed with the humectant and that mixture is subsequently mixed with water in step (c).

19. A method as claimed in any one of claims 15 to 18 wherein step (b) comprises adding the particles of zinc oxide to the mixture from step (a) under vigorous stirring.

20. A method as claimed in any one of claims 15 to 19 whereon step (c) comprises very slowly adding the mixture of water and humectant and optionally salt and preservative to the mixture from step (b).

21. A method as claimed in any one of claims 15 to 20 wherein the mixture of all ingredients resulting from step (c) is homogenised by further mixing to obtain a homogenous mixture.

Description

DESCRIPTION OF EMBODIMENTS

[0039] A composition was made from the following ingredients:

TABLE-US-00001 Phase INCI Name % w/w Function A Polyglyceryl-3 Polyricinoleate 7.50 Emulsifier (and) Sorbitan Sesquioleate (and) Cetyl Ricinoleate (and) Glyceryl Caprate (and) Cera Alba (and) Magnesium Stearate Simmondsia Chinensis (Jojoba) 8.00 Emollient Seed Oil Salicylic Acid 0.20-0.90 B Zinc Oxide (and) Coco- 38.50 Inorganic UV Filter Caprylate/Caprate (and) Polyglyceryl-3 Polyricinoleate (and) Isostearic Acid C Water 37.00

[0040] The composition was prepared by combining a sensory modifier, anti-microbial agent and salicylic acid to an amount less than 4% by weight, with the ingredients of phase A. The combining ingredients were heated to 80-85° C. with stirring until all components were molten/dissolved. Phase B was added to the phase A mixture with vigorous stirring, whilst maintaining temperature. The humectant, preservatives and salt were mixed together to an amount less than 6% by weight. Water was added to that mixture with stirring until all components were fully dissolved to form phase C. Phase C was very slowly added to the mixture of phases A and B with intensive stirring, whilst maintaining temperature. The resulting mixture was then homogenised for one minute per 100 g of mixture. The mixture was cooled to room temperature whilst undergoing vigorous stirring during cooling.

[0041] The composition set out above was tested and found to have an SPF of at least 30. It is expected that the composition will demonstrate effective treatment of acne in a number of patients.

[0042] The present inventors are not aware of any existing anti-acne compositions that have a high SPF factor and can therefore also function as a sunscreen. Indeed, conventional thinking in this art is that sunscreens exacerbate acne because sunscreen tends to block the pores of the skin. In contrast, most medical practitioners believe that the pores of the skin should be cleared in order to properly treat acne. Further, anti-acne compositions typically contain a number of quite aggressive chemicals and the interaction of those chemicals with other compounds can be unpredictable. Indeed, the present inventors took in excess of 2 years of experimentation to arrive at a composition that is effective in treating acne, has a good SPF rating and is stable with a reasonable shelf life.

[0043] 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.

[0044] 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.

[0045] 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.