In vitro cytotoxicity of methylated phenylenediamines

Abstract The acute cytotoxicities of methylated phenylenediamines (PDs) were evaluated with the neutral red assay, using BALB/c 3T3 mouse fibroblasts as the bioindicators. When the test agents were grouped according to their degree of methylation, good correlations were noted between their in vitro cytotoxicity and their in vivo myotoxicity to experimental animals, as well as to their in vitro autoxidation rates. For test agents of comparable methylation, the sequence of potency was ring-methylated p -PD > N - methylated p -PD >> N -methylated o -PD > N -methylated m -PD.