Compositions Comprising Solid Particles Entrapped In Collapsed Polymeric Microspheres, And Methods Of Making The Same
OwnerMilan F. Sojka, Phillip Cummins +2inventors
InventorsMilan F. Sojka, Phillip Cummins, Christina G. Fthenakis, Jean Harry Xavier
Life of this patent
Estimating the term…
Abstract
The present invention relates to topical compositions containing solid particles that are stabilized via entrapment by microspheres. Each of the microspheres contains a collapsed polymeric shell that has entrapped therein one or more solid particles. The solid particles are preferably formed of zinc oxide or titanium dioxide or both, which can readily be used either alone or in combination with other sunscreen agents to form sunscreen compositions of broader UV protection spectrum and enhanced photostability.
Claims32
A topical composition comprising a dispersion of microspheres in a cosmetically or pharmaceutically acceptable carrier, wherein each of said microspheres comprises a collapsed polymeric shell having entrapped therein one or more solid particles.
A microsphere comprising a collapsed polymeric shell having entrapped therein one or more solid particles, wherein the collapsed polymeric shell is further coated with a liquid-impermeable membrane.
A topical sunscreen composition comprising a dispersion of microspheres in a cosmetically or pharmaceutically acceptable carrier, wherein each of said microspheres comprises a collapsed polymeric shell having entrapped therein one or more solid particles that comprise titanium dioxide, zinc oxide, or a combination thereof.
A method for modifying or treating solid particles, comprising:
- (a) forming a gelled mixture by mixing either simultaneously or sequentially in any order (1) hollow microspheres each comprising a deformable polymeric shell having entrapped therein an expandable fluid, (2) a polar organic solvent capable of swelling but not dissolving the polymeric shells of the hollow microspheres, and (3) solid particles, wherein micro-channels are formed in the swelled polymer shells to allow entry of the solid particles into the hollow microspheres and exit of the expandable fluid therefrom, thereby forming microspheres that each comprises a collapsed polymeric shell in a gelled state and has one or more of said solid particles entrapped therein;
- (b) removing the expandable fluid and the polar organic solvent from the gelled mixture;
- and
- (c) coating the microspheres with a film-forming material to form a liquid-impermeable membrane thereon.
Dependencies are inferred from the claim text.