SUBCHRONIC AND DEVELOPMENTAL TOXICITY STUDIES OF VAPORIZED DIISOPROPYL ETHER IN RATS

Two inhalation studies were performed with a vaporized sample of comme rcial-grade diisopropyl ether (DIPE). In the subchronic study, Sprague -Dawley rats (14/sex) were exposed to 0 (both untreated and sham-expos ed controls), 480, 3300, or 7100 ppm DIPE for 6 h/d, 5 d/wk, for simil ar to 90 d. DIPE itself accounted for 91-95% of the vapors, with the r emainder being a mixture of 27-29 compounds. Exposure to DIPE did not adversely affect clinical signs, body weight, serum chemistry, hematol ogy, or the number of sperm or spermatids. Exposure of males to 7100 p pm resulted in hypertrophy of liver cells associated with increased li ver weight and in increased kidney weight with an increased incidence of hyaline droplets in proximal tubules of the kidney. Females had inc reased weight of both liver and kidney, although kidney increased only in relation to sham-exposed controls and no morphological changes wer e observed in either organ. At 3300 ppm, weights of liver and kidney w ere again increased in males; the liver weights were increased in fema les only compared to sham-exposed controls and not untreated controls. No abnormalities were observed morphologically. No changes were obser ved with 480 ppm. In the developmental toxicity study, pregnant Spragu e-Dawley rats (22/group) were exposed to 0 (both untreated and sham-ex posed controls), 430, 3095, or 6745 ppm for 6 h/d on gestation d 6-15. Animals were sacrificed on gestation d 20. With 6745 ppm, dams had a slight reduction in body weight gain and a significant decrease in foo d consumption. A concentration-related increase in the incidence of ru dimentary 14th ribs was observed, but its significance was uncertain. There was no apparent toxicity, either maternal or fetal, at the lowes t exposure concentration. Both studies indicated a low order of toxici ty for DIPE.