Safety of Nanoparticles in Sunscreens

Abstract

More than 1000 sunscreen products are marketed in Australia, and an increasing proportion (about one-third) incorporate engineered nanoparticles (ENPs). Defined as manufactured particles having one or more dimensions less than 100nm (0.00001cm), ENPs exploit the altered chemical reactivity and other changes that reduction to nanosize elicits.

ENPs in sunscreen, such as titanium dioxide (TiO2) and zinc oxides, constitute effective broad-spectrum ultraviolet radiation (UVR) blocking agents with enhanced cosmetic transparency. The Australian Therapeutic Goods Administration (TGA), in approving such products, has stated that "there is no evidence that sunscreens containing these materials pose any risk to the people using them". Similarly, authors of a recent article (written in collaboration with representatives of a cosmetic company) interpret the evidence as confirming that ENPs do not penetrate below the stratum corneum, or only in small amounts, producing limited cellular toxicity. Information on sunscreen packaging is not required to disclose the presence of ENPs.

A New South Wales Government committee has recommended that, for regulatory purposes, ENPs be considered new chemical entities that require increased safety data. Policymakers should increase funding for objective research in this area (such as that by Macquarie University and the flagship project in nanotechnology of the CSIRO [Commonwealth Science and Industry Research Organisation]). Until such safety data are available, the TGA should apply the "precautionary principle" and, at a minimum, increase packaging information about nanoparticles in sunscreens.

Keywords: Nanotechnology, nanoparticles, sunscreens, safety, precautionary principle, ethics, public health regulation