The
Polypropylene Glycol (PPG) Stearyl
Ethers are
polypropylene ethers of stearyl
ether that function as skin-conditioning agent in cosmetic formulations. Few data on the PPG Stearyl
Ethers were available. Data on chemically related PPG Butyl
Ethers were reviewed as a further basis for the assessment of safety. The amounts of PPG Butyl
Ethers absorbed from the digestive tract were inversely proportional to the molecular weights on the compounds; skin penetration was slow to nil. During metabolism, the butyl group was removed and oxidized, and the chains were fragmented, oxidized to weak
acids, and eliminated in the urine. Little acute oral toxicity was seen in animal studies. In general, the PPG Butyl
Ethers were very toxic by the intravenous route and were slightly toxic to nontoxic by the intraperitoneal and subcutaneous routes. The smaller molecular weight
ethers were generally more toxic than the larger molecular weight
ethers. PPG-2 Butyl
Ether vapor was nontoxic by the inhalation route. Undiluted
PPG-15 Stearyl
Ether was practically nonirritating to the eyes of rabbits, and PPG Butyl
Ethers had minor to moderate conjunctival irritation, opacity, and
iritis.
PPG-15 Stearyl
Ether was slightly irritating to rabbit skin. PPG-2 Butyl
Ether caused minor, transient
erythema and desquamation during a 4-hour occlusive patch test. PPG-2 Butyl
Ether did not irritate the skin of pregnant mice, was nontoxic to dams, and was not teratogenic. PPG-9-13 Butyl
Ether was noncarcinogenic when fed to rats. PPG-40 Butyl
Ether was nonsensitizing in clinical tests. These data were considered by the Cosmetic Ingredient Review Expert Panel to support the safety of PPG Stearyl
Ethers at their current use concentrations (2% to 10%, but not greater than 25%). Data on the component ingredients,
Propylene Glycol, PPG, and Steraryl Alcohol, from previous cosmetic ingredient safety assessments were also considered and found to support the safety of PPG Stearyl
Ethers.