Electronic cigarettes are a recent development in tobacco harm reduction. The present study investigated the potential subchronic inhalation toxicity of menthol liquid for electronic cigarettes in Sprague–Dawley rats. Four groups of 10 rats of each gender were exposed to menthol liquid by nose-only inhalation at concentrations of 0, 0.4, 1.2, or 3.6 mg/L for 6 h per day, 5 days/week over a 13-week period. During the study period, clinical signs, mortality, body weight, food consumption, ophthalmoscopy, urinalysis, hematology, serum biochemistry, gross pathology, organ weights, and histopathology were examined. No toxicologically significant changes were observed in any of the inhalation exposure groups. In the present experimental conditions, the no-observed-adverse-effect level was considered to be greater than 3.6 mg/L/6h/day in the rats. Also, menthol liquid for electronic cigarettes showed no evidence of mutagenic activity in the mouse.
Keywords: Electronic cigarettes, Menthol liquid, Subchronic toxicity, No-observed-adverse-effect level, Micronucleus assay
