Zinc Oxide [nano]

Background

In the opinion on Zinc Oxide adopted on the 18 September 2012, the SCCS considered that the use of nano forms and non -nano forms of ZnO at concentrations of up to 25% as a UV filter in sunscreens could be considered not to pose a risk of adverse effects in humans after dermal application. This does not apply to other applications that might lead to inhalation exposure to ZnO nanoparticles (such as sprayable products). Also, this assessment only applies to ZnO nanoparticles that are included in this dossier, or are similar materials that have the following characteristics:
• ZnO nanoparticles of purity ≥99%, with wurtzite crystalline structure and physical appearance as described in the dossier, i.e. clusters that are rod-like, star-like and/or isometric shapes
• ZnO nanoparticles with a median diameter (D50: 50% of the number below this diameter) of the particle number size distribution between 30 nm and 55 nm, and the D1 (1% below this size) above 20 nm
• ZnO nanoparticles that are either uncoated, or coated with triethoxycaprylylsilane, dimethicone, dimethoxydiphenylsilanetriethoxycaprylylsilane cross-polymer, or octyltriethoxy silane
• ZnO nanoparticles that have a comparable solubility to that reported in the dossier, i.e.below 50 mg/L …