abstract |
The present invention relates to a sunscreen formulation comprising: a dermatologically acceptable organic excipient; an agent absorbing UV rays; and an SPF enhancer, the SPF enhancer comprising a multilayer polymeric particle having a core comprising polymerized units of a monoethylenically unsaturated carboxylic acid core monomer and an ethylenically unsaturated nonionic core monomer; an inner bark comprising polymerized units of an ethylenically unsaturated nonionic inner bark monomer; a monoethylenically unsaturated carboxylic acid inner shell monomer and an aliphatic inner bark monomer; an outer shell comprising polymerized units of an ethylenically unsaturated nonionic outer shell monomer; an aliphatic outer shell monomer; a monoethylenically unsaturated non-carboxylic acid outer shell monomer and an ethylenically unsaturated surfactant outer shell monomer. The core, when dry, contains a void space and the multilayer polymeric particle has an average particle size, when dry, of between 50 and 1000 nm. |