Optically activated particles for use in cosmetic compositions
View Patent ↗Optically activated particles for use in cosmetic and pharmaceutical compositions are disclosed. The optically activated particles include a solid substrate having a fluorescent compound fixed thereto, and coated or encapsulated with a transparent or translucent coating of crosslinked polyvinyl alcohol. The optically activated particles absorb light at a UV wavelength and emit visible light at longer wavelengths, and are able to both absorb and scatter light in a diffuse manner in order to reduce the visual perception of skin imperfections, including cellulite, wrinkles, shadows, skin discolorations, blotchiness, and mild scars.
1. An optically activated particle comprising
(a) a solid substrate;
(b) a fluorescent compound fixed on the solid substrate; and
(c) a crosslinked polyvinyl alcohol shell covering the solid substrate and fluorescent compound.
2. The particle of claim 1 wherein the solid substrate comprises a synthetic polymeric substrate, a natural polymeric material, an insoluble salt, a mineral, or a mixture thereof.
3. The particle of claim 2 wherein the solid substrate comprises a synthetic polymeric substrate selected from the group consisting of a polyamide, a polyacetate, a polyester, a polyacrylic, a polyethylene, a polypropylene, a rayon, a polyvinyl chloride, and mixtures thereof.
4. The particle of claim 2 wherein the solid substrate comprises a natural polymeric material selected from the group consisting of cellulose, regenerated cellulose, starch, a microcrystalline cellulose, and mixtures thereof.
5. The particle of claim 1 wherein the solid substrate has a median particle size of about 0.1 to about 50 microns in diameter.
6. The particle of claim 1 wherein the solid substrate has a median particle size of about 2 to about 15 microns in diameter.
7. The particle of claim 1 wherein the substrate, solid or hollow, is a sphere, a cube, a cylinder, a tetrahedroid, a rhomboid, a plate, or is irregularly shaped.
8. The particle of claim 1 wherein the substrate is a solvent swollen substrate, said solvent comprising an alcohol, diol, polyol, or mixtures thereof.
9. The particle of claim 1 wherein the fluorescent compound is present in an amount of about 0.01% to about 1%, by weight of the solid substrate.
10. The particle of claim 1 wherein the fluorescent compound is present in an amount of about 0.05% to about 0.5%, by weight of the solid substrate.
11. The particle of claim 1 wherein the fluorescent compound is selected from the group consisting of a 4,4′-diaminostilbene-2,2′-disulfonic acid, a 2-(stilben-4-yl)naphthotriazole, a 2-(4-phenylstilben-4-yl)benzoxazole, a bis-(azol-2-yl)stilbene, a 1,4-bis(styryl)benzene, a 4,4′-bis(styryl)biphenyl, a 1,3-diphenyl-2-pyrazoline, a bis(benzooxazol-2-yl), a bis(benzimidazol-2-yl), a 2-(benzofuran-2-yl)benzimidazole, a coumarin, a carbostyril, a naphthalimide, a quaternized pyridotriazole, a pyrene compound, a 3,7-diaminodibenzothiophene-2,8-disulfonic acid-5,5-dioxide, and mixtures thereof.
12. The particle of claim 1 wherein the crosslinked polyvinyl alcohol is about 70% to 100% hydrolyzed.
13. The particle of claim 1 wherein the crosslinked polyvinyl alcohol is present in an amount of about 0.01% to about 25%, by weight of the particle.
14. The particle of claim 1 wherein the crosslinked polyvinyl alcohol is crosslinked by a multifunctional aldehyde.
15. A topically applied composition comprising optically activated particles of claim 1 .
16. The composition of claim 15 wherein the composition is a liquid comprising about 0.5% to about 20% of the optically activated particles, by weight of the composition.
17. The composition of claim 15 wherein the composition is a solid comprising about 0.5% to about 50% of the optically activated particles, by weight of the composition.
18. The composition of claim 15 selected from the group consisting of a skin lotion, a cream, a hair shampoo, a body rinse, a bath gel, a skin-cleansing agent, a hair conditioner, a skin coloring composition, a hair colorant, a foundation liquid, a foundation powder, a topical skin treatment.
19. A method of reducing a visual perception of skin imperfections comprising topically applying optically activated particles of claim 1 to human skin.
20. The method of claim 19 wherein the skin imperfection is selected from the group consisting of wrinkles, cellulite, skin discoloration, shadows, pores, scars, varicose veins, follicles, and blotchiness.