Mutagenic epoxide impurities discovered in two new beta-adrenergic blocking agents.

Preparations of two new beta-adrenergic blocking drugs, Zami 1305 [1-(2-nitro-3-methyl-phenoxy)-3-tert-butylaminopropan-2-ol] and Zami 1327 [1-(6-nitro-3-methyl-phenoxy)-3-tert-butylaminopropan-2-ol], were found to be contaminated by expoxides which are direct acting mutagens on TA 100 and TA 1535 in the Salmonella/microsome mutagenicity test. Because of the suggested correlation between mutagenicity and carcinogenicity of a chemical [10,11], beta-adrenergic blocking agents contaminated by mutagenic expoxide impurities may be a health hazard.