title: LC50 Determination of tert-Butyl Acetate using a Nose Only Inhalation Exposure in Rats.
abstract: tert-Butyl acetate (TBAc) is an organic solvent, which is commonly used in architectural coatings and industrial solvents. It has recently been exempted from the definition of a volatile organic compound (VOC) by the Air Resources Board (ARB) . Since the use of TBAc as a substitute for other VOCs has increased, thus its potential risk in humans has also increased. However, its inhalation toxicity data in the literature are very limited. Hence, inhalation exposure to TBAc was carried out to investigate its toxic effects in this study. Adult male rats were exposed to TBAc for 4 h for 1 day by using a nose-only inhalation exposure chamber (low dose, 2370 mg/m(3) (500 ppm) ; high dose, 9482 mg/m(3) (2000 ppm) ) . Shamtreated control rats were exposed to clean air in the inhalation chamber for the same period. The animals were killed at 2, 7, and 15 days after exposure. At each time point, body weight measurement, bronchoalveolar lavage fluid (BALF) analysis, histopathological examination, and biochemical assay were performed. No treatment-related abnormal effects were observed in any group according to time course. Based on those findings, the median lethal concentration (LC50) of TBAc was over 9482 mg/m(3) in this study. According to the MSDS, the 4 h LC50 for TBAc for rats is over 2230 mg/m(3). We suggested that this value is changed and these findings may be applied in the risk assessment of TBAc which could be beneficial in a sub-acute study.
authors.affiliation: Inhalation Toxicology Center, Korea Institute of Toxicology, Jeollabuk-do 580-185.
authors.forename: Young-Su
authors.initials: YS
authors.lastname: Yang
authors.forename: Jinsoo
authors.initials: J
authors.lastname: Lee
authors.forename: Soonjin
authors.initials: S
authors.lastname: Kwon
authors.forename: Heung-Sik
authors.initials: HS
authors.lastname: Seo
authors.forename: Seong-Jin
authors.initials: SJ
authors.lastname: Choi
authors.forename: Hee-Jin
authors.initials: HJ
authors.lastname: Yu
authors.forename: Jeong-Ah
authors.initials: JA
authors.lastname: Song
authors.forename: Kyuhong
authors.initials: K
authors.lastname: Lee
authors.forename: Byoung-Seok
authors.initials: BS
authors.lastname: Lee
authors.forename: Jeong-Doo
authors.initials: JD
authors.lastname: Heo
authors.forename: Kyu-Hyuk
authors.initials: KH
authors.lastname: Cho
authors.forename: Chang-Woo
authors.initials: CW
authors.lastname: Song
keywords: Bronchoalveolar lavage fluid analysis; Inhalation toxicity; Nose-only inhalation exposure chamber; Rats; tert-Butyl acetate