Final Report on the Safety Assessment of Polybutene

Abstract

Polybutenes are the isotactic polymers of isobutene and n-butene. Polybutenes provide viscosity or emulsifiability to more than 80 cosmetic products in concentrations up to 50%. The results of acute oral and percutaneous toxicity tests of Polybutenes show these materials to be relatively harmless. Acute skin irritation tests on rabbits showed no or mild irritation. Other test results indicate that Polybutenes are not toxic: (a) there were no observable effects in rats after inhalation at concentrations up to 18.5 mg/l of air; (b) there was only mild, transient eye irritation in rabbits; (c) intravaginal application of concentrated Polybutene daily for 30 days produced no observable effect in rabbits. Chronic oral toxicity in rats fed up to 20,000 ppm for three successive generations showed no impairment in reproduction. The available human clinical data indicated only very mild effects. Skin tests for sensitization, irritancy, phototoxicity, and photosensitization were limited to cosmetic formulations. On the basis of the available information, it was concluded that Polybutenes are safe as presently used in cosmetics.