Repeated-Dose (28-Day) Inhalation Toxicity of Isopropylethylene Glycol Ether in Rats

Abstract

Subacute (28-d) inhalation toxicity studies of isopropylethylene glycol ether (purity 99.2–99.3%) were carried out in young adult Wistar rats. Four groups of 10 rats/sex each were exposed to 0, 142, 441, or 891 ppm for 4 wk, 6 h/d, 5 d/wk. Since a no-observed-adverse-effect level could not be established, a second similar study was performed, using exposure concentrations of 0, 10, 30, or 100 ppm; in addition, five rats/sex/group were kept for a 14-d recovery period.At the end of the treatment period, hemolytic anemia was observed in male and female rats exposed to 891, 441, or 142 ppm. Mild hemolytic anemia was found in female rats exposed to 700 ppm, but had disappeared after the 14-d recovery period. Higher plasma bilirubin values were observed in rats exposed to 891 ppm, and decreased urinary pH values occurred in rats exposed to 891 or 447 ppm.A concentration-related increase in absolute and relative spleen weight accompanied by extramedullary hematopoiesis and brown pigment accumulation in the spleen was observed in the 441 and 891 ppm groups. Extramedullary hematopoiesis and brown pigment accumulation in the spleen were also observed in the spleen of rats exposed to 142 ppm.It was concluded that the no-observed-adverse-effect level in these studies is 30 ppm in rats.