Final Report on the Safety Assessment of Polyoxymethylene Urea

Abstract

Polyoxymethylene Urea is a variable molecular weight polymer formed in stages from the condensation reaction of urea with formaldehyde. It is used in a wide range of cosmetic formulations as a bulking agent and to form the outer shell of microcapsules. Because of the nature of the polymerization process, residual formaldehyde is present at levels typically between 17 and 30 ppm. Polyoxymethylene Urea shows low toxicity. The oral LD₅₀ in rats was 10 g/kg for the bulk material and 20 g/kg when the microcapsule form was used. Polyoxymethylene Urea was a mild skin irritant and caused mild, transient ocular irritation in rabbits. Ames tests were negative for mutagenesis. Clinical data showed no irritation or sensitization. On the basis of the data, it is concluded that Polyoxymethylene Urea is safe for use as a cosmetic ingredient. A previous determination, however, that the concentration of free formaldehyde in cosmetic formulations should not exceed 0.2% was considered appropriate for this ingredient as well. Likewise, the previous finding that the safety of formaldehyde was not ensured in cosmetic products intended to be aerosolized is extended to this ingredient.