[Safety assessment of nanomaterials for development of nano-cosmetics]

A diverse array of nanomaterials (NMs), such as amorphous nanosilica (nSP), carbon nanotubes and titanium dioxide, has become widespread in use due to the development of nanotechnology. NMs are already being applied in universal fields because they have unique physicochemical properties. On the other hands, the safety of NMs has not been well assessed, because NMs have been considered as safe as common larger sized materials which are known not to be absorbed by the body. Because NMs have the potential to improve the quality of human life, it is essential to ensure the safety of NMs and provide information for designing safer NMs. In this regard, we studied the biological distribution and hazard identification of nSP following dermal administration, because nSP is used NMs in the cosmetics field. In the future, our study would help to set the no observed adverse effect level (NOAEL) and acceptable daily intake (ADI), and be useful information for the safety/hazard assessment and evaluation.