Assessment of the teratogenic potential of surfactants Part III — dermal application of LAS and soap

Abstract

The surfactant linear alkylbenzene sulphonate (LAS) was examined for embryotoxic and teratogenic potential following percutaneous administration. Solutions containing, 0.03, 0.3 and 3% LAS were applied to shaved skin during pregnancy days 2–13 in mice, 2–15 in rats and 1–16 in rabbits. Dosages employed were 0.5 ml/rat or mouse/day and 10 ml/rabbit/day. For comparison further groups of rats and mice were similarly treated with concentrations of 0.3, 3 and 30% of a standard soap solution. Marked maternal toxicity in the form of local skin reaction, irritability, weight loss and failure to maintain or establish pregnancy was evident in mice treated with LAS 3% or soap, 3 or 30%; marked local reaction and weight loss also occurred in rabbits receiving LAS 3% but the reduction in the number of pregnancies maintained was not significant. Moderate maternal toxicity was observed among mice treated with LAS, 0.3% and mild maternal toxicity in rats receiving LAS 3% or soap 30% and rabbits receiving LAS 0.3%. Effects on litter parameters were generally restricted to dosages causing marked maternal toxicity in mice, the principal effects being higher foetal loss (with consequent reduction in viable litter size) arising from an increased incidence of total litter losses. When dams showing total litter loss were excluded from the calculations, litter parameters were not unduly different from those of controls. Although LAS at 3% was considered to show marked maternal toxicity in the rabbit, the slightly higher foetal loss and lower litter size did not differ significantly from control values. The moderate maternal toxicity of LAS, 0.3% in the mouse correlated with a higher incidence of embryonic deaths and lower litter size but only the former differed significantly from the corresponding control value. At dosages that were non-toxic or only slightly toxic to the dam, litter parameters were not adversely affected as the only significant deviations from control values were in respect of the higher mean pup weights observed in rats treated with LAS 3%, or all dosages of soap and the consequent higher litter weights with soap 0.3 or 30%. The incidences of major malformations, minor visceral or skeletal anomalies, and skeletal variants provided no conclusive evidence of specific teratogenicity even at maternally toxic dosages.