Developmental toxicity evaluation of rats dosed orally or cutaneously withoctoxynol-9

Pregnant CD(R) rats were dosed cutaneously (530, 1600 or 4270 mg kg(-1) day (-1)) or fed diets containing octoxynol-9 (70 or 340 mg kg(-1) day(-1)) dur ing the major period of organogenesis. Monitors for maternal toxicity inclu ded clinical observations, body weight, organ weight and food consumption. Fetuses were evaluated for body weight and for external, visceral and skele tal abnomalities. Maternal effects were noted in darns dosed cutaneously wi th 4270 mg kg(-1) day(-1) octoxynol-9, and included excoriation, exfoliatio n/desquamation in the area of treated skin, urine stains, perinasal encrust ation and audible respiration. In addition, maternal weight gains were redu ced during the dosing period, Octoxynol-9, dosed orally or cutaneously to g ravid rats, had no effect on pregnancy performance but increased the incide nces of a number of developmental abnormalities in the offspring. Most nota ble was the induction of supernumerary ribs arising from the lumbar and cer vical regions. Other skeletal abnormalities included decreased incidences o f poorly ossified supraoccipital and hyoid bones and zygomatic arches, sugg esting an enhanced ossification in the neck and head regions. Increased inc idences of two fetal visceral abnormalities, displaced testes in darns dose d orally with 340 mg kg(-1) day(-1) and atelectasis in darns dosed cutaneou sly with 1600 or 4270 mg kg(-1) day(-1) were also observed, Copyright (C) 1 999 John Wiley & Sons, Ltd.