Acute inhalation toxicity studies in several animal species of an ethylene oxide/propylene oxide copolymer (UCON 50-HB-5100).

ABSTRACTAn acute inhalation toxicity study in several species of animals with an ethylene oxide/propylene oxide copolymer (EO/PO) having a molecular weight of 4000 [UCON-50-HB-5100, CAS #9038-95-3] was designed to determine if any species variation could be shown. Species tested included; rats, mice, hamsters, guinea pigs, and dogs. the test material was administered as a respirable liquid aerosol for 4 hours at target concentrations of 50, 100, 200, and 500 mg/m3. A vehicle control group was exposed to a distilled water aerosol. the 4 hours LC50′s were calculated to be 147 mg/m3 [rats], 174 mg/m3 [mice], 293 mg/m3 [guinea pigs] and 511 mg/m [hamsters]. the dog LC50 was determined to be greater than 500 mg/m3 since all the test animals survived exposure to this concentration. These values show that rats and mice were the most sensitive species with a declining response in guinea pigs, hamsters and dogs. Lung weights were increased at all exposure concentrations in rats, mice and hamsters. Lung weights wer...