| toxicity summary | IDENTIFICATION AND USE: Stearic acid is a solid. It is used in suppositories, coating enteric pills, ointments and for coating bitter remedies. It is also used in manufacturing stearates of aluminum, zinc, and other metals, stearin soap for a liniment invented by Paracelsus, candles, phonograph records, insulators, modeling compounds, impregnating plaster of Paris, in vanishing creams and other cosmetics. Stearic acid is used in animal cell culture. HUMAN STUDIES: The greatest danger from ingestion of large quantities of stearic acid is intestinal obstruction. Skin sensitization is unusual. Aspiration or inhalation of stearic acid could cause chemical pneumonitis. Implantation of stearic acid will cause foreign body reaction. ANIMAL STUDIES: Skin lotion formulations containing 2.8% stearic acid administered at doses of 15 g/kg by gavage to groups of 10 rats resulted in 1 death. Normal behavior and appearance were observed, and there were no gross alterations in surviving rats. No ocular irritation was produced in 6 rabbits by commercial grade stearic acid, whereas mild conjunctival erythema was produced in 3 of 6 rabbits by commercial grade triple-pressed stearic acid. Treatment with 35% stearic acid in corn oil and 50% stearic acid in petrolatum was primarily producing mild conjunctival erythema, which had subsided within 2 days. Intravenous infusion of large doses of stearic acid were thrombogenic in rats, rabbits, and dogs, causing blood platelet aggregation and acute heart failure. When diets containing 5 to 50% stearic acid were fed to weanling mice for 3 weeks, depression of weight gain was seen above the 10% dietary level. Mortality occurred only with the 50% diet. The effects were less noticeable in adult mice. Rats fed 5% stearic acid as part of a high-fat diet for 6 weeks, or 6% stearic acid for 9 weeks, showed a decreased blood clotting time and hyperlipemia. Rats fed 50 g/kg/day stearic acid for 24 weeks developed reversible lipogranulomas in adipose tissue. No significant pathological lesions were observed in rats fed 3000 ppm stearic acid orally for about 30 weeks, but anorexia, increased mortality, and a greater incidence of pulmonary infection were observed. Single intraperitoneal doses of stearic acid in mice, ranging from approximately 15 to 500 mg/kg, caused no fatalities, but at the highest dose level caused a loss of body weight. In cats, low doses of stearic acid produced elevated pulmonary but decreased systemic blood pressure. Doses greater than 5 mg caused apnea, a fall in blood pressure, and convulsions leading to death. Stearic acid was tested for mutagenicity using the Ames test with Salmonella typhimurium strains TA98, TA100, TA1535, TA1537, and TA1538. Stearic acid had no mutagenic activity over background in the strains tested with and without metabolic activation. |
