title: A 52-week repeated dose toxicity study of ultraviolet absorber 2-(2'-hydroxy-3',5'-di-tert-butylphenyl)benzotriazole in rats.
abstract: A 52-week repeated dose toxicity study of an ultraviolet absorber, 2-(2'-hydroxy-3',5' -di-tert-butylphenyl)benzotriazole (HDBB), was conducted according to OECD TG 452 under GLP. CD(SD)IGS rats were given HDBB by gavage at 0, 0.1, 0.5, or 2.5 mg/kg/day in males and 0, 0.5, 2.5, or 12.5 mg/kg/day in females. No substance-related deaths or clinical signs of toxicity were observed in any group; however, a lowered body weight was found from day 36 to the end of the 52-week administration period at 2.5 mg/kg in males. At the completion of the dosing period, a decrease in red blood cells at 0.5 mg/kg and higher, and in hematocrit at 2.5 mg/kg, was detected in males. Blood biochemical changes, including increases in the levels of alkaline phosphatase and glucose and the A/G ratio, were also found at 0.5 mg/kg and higher in males and at 12.5 mg/kg in females. At necropsy, absolute and relative liver weight was increased at 0.5 mg/kg and higher in males and at 12.5 mg/kg in females. Histopathological changes were observed in the liver; centrilobular hypertrophy of hepatocytes at 0.5 mg/kg and higher in males, and at 12.5 mg/kg in females, and altered hepatocellular foci at 0.5 mg/kg and higher, and cystic degeneration and lipofuscin deposition in hepatocytes at 2.5 mg/kg in males. Based on these findings, the no observed adverse effect level was concluded to be 0.1 mg/kg/day in male rats and 2.5 mg/kg/day in female rats.
authors.affiliation: Biological Safety Research Center, National Institute of Health Sciences, Tokyo, Japan.
authors.forename: Mutsuko
authors.initials: M
authors.lastname: Hirata-Koizumi
authors.forename: Hidehiro
authors.initials: H
authors.lastname: Ogata
authors.forename: Toshio
authors.initials: T
authors.lastname: Imai
authors.forename: Akihiko
authors.initials: A
authors.lastname: Hirose
authors.forename: Eiichi
authors.initials: E
authors.lastname: Kamata
authors.forename: Makoto
authors.initials: M
authors.lastname: Ema
mesh_terms: D000284:Administration, Oral; D000469:Alkaline Phosphatase / Q000097:blood; D000818:Animals; D001786:Blood Glucose / Q000187:drug effects; D001835:Body Weight / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D004912:Erythrocytes / Q000187:drug effects; D005260:Female; D006321:Heart / Q000187:drug effects; D008099:Liver / Q000187:drug effects / Q000473:pathology; D008297:Male; D019055:No-Observed-Adverse-Effect Level; D009929:Organ Size; D011837:Radiation-Protective Agents / Q000008:administration & dosage / Q000633:toxicity*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012737:Sex Factors; D013997:Time Factors; D036401:Toxicity Tests, Chronic; D014230:Triazoles / Q000008:administration & dosage / Q000633:toxicity*; D014466:Ultraviolet Rays
chemical_list: D001786:Blood Glucose; D011837:Radiation-Protective Agents; D014230:Triazoles; C525485:2-(2'-hydroxy-3',5'-di-tert-butylphenyl)benzotriazole; D000469:Alkaline Phosphatase