Topical sunscreen composition, method of preparation, and use thereof
Inventors
DUDLEY, DENIS • Heinar, Thomas • DUDLEY, SARA
Assignees
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Publication Number
US-10434048-B2
Publication Date
2019-10-08
Expiration Date
Abstract
A topical sunscreen composition includes metal oxide sunscreen particles, polylactic acid, and a cosmetic carrier in which the metal oxide sunscreen particles and polylactic acid are dispersed. A method of preparing a topical sunscreen composition includes dispersing metal oxide sunscreen particles and polylactic acid in a cosmetic carrier. A method of protecting human skin from ultraviolet (UV) radiation includes applying to human skin a topical sunscreen composition including metal oxide sunscreen particles and polylactic acid dispersed in a cosmetic carrier.
Core Innovation
The invention relates to a topical sunscreen composition that combines metal oxide sunscreen particles and polylactic acid (PLA) particles. The metal oxide sunscreen particles and the polylactic acid particles are discrete and separate particles dispersed in a cosmetic carrier, and the composition specifies quantitative ranges for the amounts of both particle types.
The polylactic acid particle diameter is defined as between about 5 microns and about 20 microns. The sunscreen composition is further defined by an ultraviolet A (UV-A) protection factor of at least 13, and the disclosure positions the combination of discrete metal oxide particles with particulate PLA as a basis for achieving UV-A performance.
In addition to the disclosed composition framework, the document describes optional inclusion of an organic UV absorbing agent in the sunscreen composition. The disclosure supports performance and formulation effects using in vitro UVA testing (COLIPA in vitro UVA method) and reports results for UV-A protection factor, SPF, and photostability when PLA is present in the specified particulate form.
Claims Coverage
The document contains three independent claims (a composition claim, a skin protection method claim, and a preparation method claim) that share a common inventive construct: discrete and separate dispersion of metal oxide sunscreen particles and polylactic acid particles of defined loading and PLA particle diameter, achieving a UV-A protection factor of at least 13.
Dispersed discrete metal oxide sunscreen particles
A topical sunscreen composition comprising between about 1 wt % and about 35 wt % metal oxide sunscreen particles dispersed in a cosmetic carrier, wherein the metal oxide sunscreen particles are discrete and separate particles.
Dispersed discrete polylactic acid particles with defined diameter
A topical sunscreen composition comprising between about 2.5 wt % and about 25 wt % polylactic acid particles dispersed in a cosmetic carrier, wherein the polylactic acid particles are discrete and separate particles and have a diameter of between about 5 microns and about 20 microns.
UV-A protection factor threshold
A topical sunscreen composition having an ultraviolet A (UV-A) protection factor of at least 13.
Applying the defined sunscreen composition to human skin
A method of protecting human skin from ultraviolet (UV) radiation by applying a sunscreen composition comprising between about 1 wt % and about 35 wt % metal oxide sunscreen particles, between about 2.5 wt % and about 25 wt % polylactic acid particles, and a cosmetic carrier wherein the metal oxide sunscreen particles and the polylactic acid particles are discrete and separate particles with polylactic acid particle diameter between about 5 microns and about 20 microns, and wherein the sunscreen composition has an ultraviolet A (UV-A) protection factor of at least 13.
Preparing the defined sunscreen composition while maintaining discrete particles
A method of preparing a topical sunscreen composition comprising dispersing between about 1 wt % and about 35 wt % metal oxide sunscreen particles and between about 2.5 wt % and about 25 wt % polylactic acid particles in a cosmetic carrier, while maintaining the metal oxide sunscreen particles and the polylactic acid particles as discrete and separate particles, wherein the polylactic acid particle have a diameter of between about 5 microns and about 20 microns, and wherein the sunscreen composition has an ultraviolet A (UV-A) protection factor of at least 13.
Claim coverage is anchored on dispersing discrete and separate metal oxide sunscreen particles and polylactic acid particles in a cosmetic carrier, with specified wt% ranges for both particle types, a polylactic acid particle diameter range of about 5 to about 20 microns, and a UV-A protection factor of at least 13. The independent claims cover the resulting topical composition, protecting human skin by applying that composition, and preparing that composition while maintaining the discrete and separate particle structure.
Stated Advantages
Improves UVA protection factor (up to ~91% reported increase with PLA addition).
Improves SPF (up to ~72% reported increase).
Improves photostability, with UVAPF photostability changes reduced to as low as ~3.00% with 20 wt% PLA.
Documented Applications
Protecting human skin from ultraviolet (UV) radiation by applying the claimed sunscreen composition.
Preparing a topical sunscreen composition by dispersing metal oxide sunscreen particles and polylactic acid particles in a cosmetic carrier while maintaining discrete and separate particles.
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