Evaluation of the Developmental Toxicity of 1-(1,2,3,4,5,6,7,8-Octahydro-2,3,8, 8-Tetramethyl-2-Naphthalenyl) Ethanone (OTNE) in Rats

The developmental toxicity of 1-(1,2,3,4,5,6,7,8-Octahydro-2,3,8,8-tetramethyl-2-naphthalenyl) ethanone (OTNE), a widely used fragrance ingredient, was evaluated in pregnant Sprague-Dawley rats (25/group) gavaged with dosages of 0 (water), 96, 240, or 480 mg/kg/d on days 7 through 17 of gestation (GDs 7–17). Rats were observed for clinical signs, abortions, premature deliveries, body weights, and feed intake. Caesarean section and necropsy were performed on GD 21. Fetuses were weighed and examined for gender, gross external changes, and soft tissue or skeletal alterations. No deaths or premature deliveries were attributed to OTNE. OTNE-related clinical signs included significantly increased incidences of excessive salivation in all 3 treatment groups, and urine-stained abdominal fur in the high dosage group. Mean body weight gains were significantly reduced by all OTNE dosages on GDs 7–10, while at 480 mg/kg/d, significant reductions continued through the remainder of the dosage period. Feed consumption generally paralleled body weight gains. Fetal body weights were reduced by 480 mg/kg/d, but not to a statistically significant degree. No fetal gross external, soft tissue, or skeletal malformations or variations were attributable to OTNE. Based on these data, maternal and developmental no-observable-adverse-effect-levels (NOAELs) of 240 mg/kg/d were established for OTNE. It was concluded that OTNE is not a developmental toxicant in rats under the conditions of this study, and that a margin of safety greater than 2700 exists between reversible developmental delays in rats and the calculated daily human exposure level of 0.086 mg/kg/d.