Photostabilization of a sunscreen composition with a combination of an α-cyano-β, β-diphenylacrylate compound and a dialkyl naphithalate
Sunscreen compositions including a dibenzoylmethane derivative, such as avobenzone, that are made more stable by the addition of (a) an α-cyano-β,β-diphenylacrylate compound, e.g., octocrylene and (b) a diester or polyester of naphthalene dicarboxylic acid (diethylhexyl 2,6-naphthalate), having a weight ratio of (a)/(b) of at least 0.95, preferably at least about 1.0. More particularly, the invention relates to sunscreen compositions which utilize a combination of octocrylene and diethylhexyl 2,6-naphthalate to stabilize other photoactive compounds present in a sunscreen composition and, in particular, to stabilize dibenzoylmethane derivatives, without, or with levels less than 0.5% by weight of, a methoxy-substituted benzophenone derivative, such as benzophenone-3.
1. A sunscreen composition, comprising a mixture of a dibenzoylmethane derivative, with (a) an α-cyano-β,β-diphenylacrylate compound, and (b) a diester or polyester of naphthalene dicarboxylic acid selected from the group consisting of formula (I), formula (II), and combinations thereof:
wherein R 1 and R 2 are the same or different and selected from the group consisting of C 1 -C 22 alkyl groups, diols having the structure HO—R 3 —OH, and polyglycols having the structure HO—R 4 —(—O—R 3 —) n —OH; wherein each R 3 and R 4 is the same or different and selected from the group consisting of C 1 -C 6 straight or branched chain alkyl groups; wherein m and n are each in a range of 1 to 100 and p is in a range of 0 to 100; wherein the weight ratio of (a)/(b) is at least 0.95.
2. The composition of claim 1 , wherein the weight ratio of (a) to (b) is at least about 1.0.
3. The composition of claim 2 , further including a methoxy-substituted benzophenone derivative in an amount of about 0.1% by weight to about 10% by weight of the sunscreen composition.
4. The composition of claim 3 , wherein the methoxy-substituted benzophenone derivative is benzophenone-3, included in the sunscreen composition in an amount less than about 0.5% by weight.
5. The composition of claim 1 , wherein said dibenzoylmethane derivative is selected from the group consisting of 2-methyldibenzoylmethane; 4-methyldibenzoylmethane; 4-isopropyldibenzoylmethane; 4-tert-butyldibenzoylmethane; 2,4-dimethyldibenzoylmethane; 2,5-dimethyldibenzoylmethane; 4,4′-diisopropyldibenzoylmethane; 4,4′-dimethoxydibenzoylmethane; 4-tert-butyl-4′-methoxydibenzoylmethane; 2-methyl-5-isopropyl-4′-methoxydibenzoylmethane; 2-methyl-5-tert-butyl-4′-methoxydibenzoylmethane; 2,4-dimethyl-4′-methoxydibenzoylmethane; 2,6-dimethyl-4-tert-butyl-4′-methoxydibenzoylmethane, and combinations thereof.
6. The composition of claim 1 , wherein said dibenzoylmethane derivative is present in a range of about 0.1% to about 25% by weight of the total weight of the composition.
7. The composition of claim 1 , wherein said α-cyano-β,β-diphenylacrylate compound is present in an amount of at least about 0.5% by weight of the total weight of the composition.
8. The composition of claim 7 , wherein said α-cyano-β,β-diphenylacrylate compound is present in an amount of about 1.0% to about 8% by weight of the total weight of the composition.
9. The composition of claim 8 , wherein said α-cyano-β,β-diphenylacrylate compound comprises 2-ethylhexyl-2-cyano-3,3-diphenylacrylate.
10. The composition of claim 1 , comprising a diester of formula (II) wherein R 1 and R 2 are 2-ethylhexane and p is 0.
11. The composition of claim 1 , wherein said diester or polyester of naphthalene dicarboxylic acid is present in a range of about 0.1% to about 15% by weight of the total weight of the composition.
12. The composition of claim 1 , wherein the weight ratio of (a) to (b) is in the range of about 1/1 to about 2/1.
13. The composition of claim 1 , further comprising a methoxy-substituted benzophenone derivative.
14. The composition of claim 13 , wherein said methoxy-substituted benzophenone derivative comprises benzophenone-3.
15. The composition of claim 13 , wherein said methoxy-substituted benzophenone derivative is present in an amount of 0.5% or less by weight of the total weight of the composition.
16. The composition of claim 1 , further comprising a photoactive compound selected from the group consisting of p-aminobenzoic acid and salts and derivatives thereof; anthranilate and derivatives thereof; dibenzoylmethane and derivatives thereof; salicylate and derivatives thereof; cinnamic acid and derivatives thereof; dihydroxycinnamic acid and derivatives thereof; camphor and salts and derivatives thereof; trihydroxycinnamic acid and derivatives thereof; dibenzalacetone naphtholsulfonate and salts and derivatives thereof; benzalacetophenone naphtholsulfonate and salts thereof; dihydroxy-naphthoic acid and salts thereof; o-hydroxydiphenyldisulfonate and salts thereof; p-hydroxydiphenyldisulfonate and salts thereof; coumarin and derivatives thereof; diazole derivatives; quinine derivatives and salts thereof; quinoline derivatives; hydroxy-substituted benzophenone derivatives; methoxy-substituted benzophenone derivatives; tannic acid; hydroquinone; benzophenone derivatives; 1,3,5-triazine derivatives, phenyldibenzimidazole tetrasulfonate and salts and derivatives thereof; terephthalylidene dicamphor sulfonic acid and salts and derivatives thereof; methylene bis-benzotriazolyl tetramethylbutylphenol and salts and derivatives thereof; bis-ethylhexyloxyphenol methoxyphenyl triazine and salts and derivatives thereof; diethylamino hydroxybenzoyl hexyl benzoate and salts and derivatives thereof; and combinations of the foregoing.
17. The composition of claim 16 , wherein said photoactive compound comprises 2-ethylhexyl-p-methoxycinnamate.
18. The composition of claim 1 , comprising an oil phase comprising said dibenzoylmethane derivative, said α-cyano-β,β-diphenylacrylate compound, said diester or polyester of naphthalene dicarboxylic acid, and a solvent system, wherein said solvent system comprises an effective amount of a polar solvent to increase the photostability of said dibenzoylmethane derivative and to increase the dielectric constant of the oil phase to at least about 7.
19. The composition of claim 18 , wherein said oil phase has a dielectric constant of at least about 8.
20. The composition of claim 18 , wherein the polar solvent comprises diethylhexyl malate, dimethyl capramide, or a combination thereof.
21. The composition of claim 18 , wherein said dibenzoylmethane derivative is selected from the group consisting of 2-methyldibenzoylmethane; 4-methyldibenzoylmethane; 4-isopropyldibenzoylmethane; 4-tert-butyldibenzoylmethane; 2,4-dimethyldibenzoylmethane; 2,5-dimethyldibenzoylmethane; 4,4′-diisopropyldibenzoylmethane; 4,4′-dimethoxydibenzoylmethane; 4-tert-butyl-4′-methoxydibenzoylmethane; 2-methyl-5-isopropyl-4′-methoxydibenzoylmethane; 2-methyl-5-tert-butyl-4′-methoxydibenzoylmethane; 2,4-dimethyl-4′-methoxydibenzoylmethane; 2,6-dimethyl-4-tert-butyl-4′-methoxydibenzoylmethane, and combinations thereof.
22. The composition of claim 21 , wherein said dibenzoylmethane derivative is present in a range of about 0.1% to about 25% by weight of the total weight of the composition.
23. The composition of claim 21 , wherein said α-cyano-β,β-diphenylacrylate compound comprises 2-ethylhexyl-2-cyano-3,3-diphenylacrylate.
24. A method of reducing contact of UV radiation with human skin comprising covering human skin with the composition of claim 1 .
25. A method of reducing contact of UV radiation with human skin comprising covering human skin with the composition of claim 2 .
26. A method of reducing contact of UV radiation with human skin comprising covering human skin with the composition of claim 3 .
27. A method of reducing contact of UV radiation with human skin comprising covering human skin with the composition of claim 4 .
28. A method of reducing contact of UV radiation with human skin comprising covering human skin with the composition of claim 13 .
29. A method of reducing contact of UV radiation with human skin comprising covering human skin with the composition of claim 14 .
30. A method of reducing contact of UV radiation with human skin comprising covering human skin with the composition of claim 15 .
31. A method of reducing contact of UV radiation with human skin comprising covering human skin with the composition of claim 16 .
32. A method of reducing contact of UV radiation with human skin comprising covering human skin with the composition of claim 17 .