STABLE SUNSCREEN COMPOSITIONS CONTAINING ZINC OXIDE

摘要

A stable, oil-in-water (O-W) emulsion-based sunscreen composition having at least one water-insoluble, organic UV-absorber having a water-solubility of much less than 0.1% by weight, contained in the oil phase of the sunscreen emulsion, comprising i) zinc oxide (ZnO) particles having a surface free of any prior coating of any inorganic oxide and hydrophobic material, remaining dispersed in the water phase of the sunscreen emulsion; ii) at least one non- or low-foaming, non-cationic, hydrophilic polymer, capable of dispersing or deflocculating the ZnO particles but incapable of thickening an aqueous composition to a viscosity of greater than 100 cps at 25°C, wherein the viscosity is measured using a Brookfield viscometer operated at 10 rpm for 15 seconds, when the polymer is added at an amount of 1%, based on the total weight of the polymer and water in the aqueous composition; iii) at least one phenolic polymer, capable of functioning as a dispersing or deflocculating agent for particulate material(s), and adsorbing at an oil-water interface; and v) a buffering agent for the water phase of the sunscreen emulsion.