Mutagenicity studies on tiopronin.

alpha-Mercaptopropionylglycine (tiopronin, Mucolysin), a drug endowed with an interesting mucolytic activity, was tested for mutagenicity by means of the following in vitro and in vivo tests: mutagenesis on S. typhimurium with and without metabolic activation, genetic mutation on S. pombe P1 with and without metabolic activation, gene conversion on S. cerevisiae D4 with and without metabolic activation, urinary assay in the mouse with S. cerevisiae D4, host mediated assay in the mouse with S. cerevisiae D4 and micronucleus test in the mouse. On the basis of the results obtained tiopronin proved to be free of mutagenic activity.