Determination of the developmental toxicity potential of butoxypropanol in rabbits after topical administration

The developmental toxicity (embryofetotoxicity or teratogenicity) and maternal toxicity of butoxypropanol, a propylene glycol ether, was evaluated in New Zealand White rabbits. Dosages of 0 (water), 10, 40 or 100 mg/kg/day, selected on the basis of the water solubility of butoxypropanol and the results of a pilot study, were administered percutaneously to groups of artificially inseminated (Day 0) female rabbits on Days 7 through 18 of gestation. The dosage volume was 2 ml/kg. The control group contained 17 does and each test group contained 19 does. Does were observed for signs of test substance effect on abortion or premature delivery, body weight, and feed consumption. On Day 29, they were euthanized and examined for pregnancy, number and placement of implantations, early and late resorptions, and live fetuses. Pregnancy occurred in 15 control does (88%) and in 16 does in each test group (84%). There were no statistically significant differences between test and control groups for maternal body weight gain, feed consumption, number of corpora lutea per ovary, implantations, live fetuses, early and late resorptions, fetal body weights, gender, or gross external changes. There were no visceral or skeletal fetal alterations at any dose tested. No signs of maternal toxicity were observed; however, mild erythema occurred at the site of application at the 100 mg/kg/day dose level. The developmental no-effect level was greater than 100 mg/kg/day.