Safety evaluation of zinc oxide nanoparticles in terms of acute dermal toxicity, dermal irritation and corrosion, and skin sensitization

To clarify the health risks related to the use of zinc oxide (ZnO) nanoparticles, acute dermal toxicity, dermal irritation and corrosion, and skin sensitization were evaluated according to the guideline for Organization for Economic Cooperation and Development (OECD) and Good Laboratory Practice (GLP). In acute dermal toxicity test using rats, there were no treatment-related mortality, clinical signs of toxicity, body weight changes, and gross findings at a dose level of 2000 mg/kg. Similarly, dermal irritation and corrosion tests using rabbits revealed no mortality, clinical signs of toxicity, and acute irritation or corrosion reaction on the skin. In a skin sensitization test using guinea pigs, there were no significant mortality, clinical signs of toxicity, body weight changes, and skin reactions 24 and 48 h after the removal of challenge patch, which was scored “0” based on the Magnusson and Kligman grading scale. Our findings suggest that the nano-sized ZnO used in this study is relatively safe since it did not induce acute dermal toxicity, dermal irritation and corrosion, and skin sensitization.