4: Final Report on the Safety Assessment of n-Butyl Alcohol

Abstract

n-BuOH is a primary aliphatic alcohol that is used in cosmetic nail products as a solvent at concentrations up to 10%. In vitro tissue permeability studies indicate that human epidermis and dermis were permeable to n-BuOH. The single oral dose LD50 of n-BuOH for rats ranged from 0.8 to 4 g/kg. The dermal LD50 has been reported as 4.2 g/kg. n-BuOH does not cause skin irritation in rabbits but is a severe rabbit eye irritant. Inhalation of n-BuOH vapors caused intoxication of laboratory animals; high concentrations were sometimes fatal. n-BuOH was not mutagenic in the Salmonella/mammalian-microsome mutagenicity test. The ingredient did not induce sister chromatid exchange or chromosome breakage in chick embryo cells or in Chinese hamster ovary cells and did not induce micronuclei formation in V79 Chinese hamster cells. Two nail formulations containing 3.0% n-BuOH were tested on 558 and 421 subjects, respectively; neither was considered an irritant or sensitizer. Clinically, n-BuOH produced edema in 4 of 105 dermatological patients. Additional clinical studies indicated that nail enamel products containing n-BuOH were neither irritants, sensitizers, nor photoallergens. Inhalation of n-BuOH can cause human nose, throat, and eye irritation. On the basis of the information in the report and only as it regards the use of n-BuOH in nail products, the ingredient is considered to be safe in the present practices of use and concentration.