Chemical behaviour of seven aromatic diisocyanates (toluenediisocyanates and diphenylmethanediisocyanates) under in vitro conditions in relationship to their results in the Salmonella/microsome test.

There are conflicting results on the mutagenicity of toluenediisocyanate (TDI) and diphenylmethanediisocyanate (MDI). It was found that the organic solvent chosen to dissolve the compounds dictates the outcome of the bacterial tests. The Salmonella/microsome tests showed uniformly mutagenic effects for all the compounds that were predissolved in DMSO.

Studies on the effect of the solvents dimethylsulfoxide and ethyleneglycoldimethylether on the mutagenicity of four types of diisocyanates in the Salmonella/microsome test.

The mutagenicity of isomers and homologs of diphenylmethanediisocyanate (4,4'-diisocyanatodiphenylmethane, 2,4'-diisocyanatodiphenylmethane, a mixture of monomeric MDI isomers, and polymeric MDI), containing 55-100% of monomeric MDI, was determined in the Salmonella/microsome test using dimethylsulfoxide (DMSO) and ethyleneglycoldimethylether (EGDE) as solvents. Positive results were obtained for DMSO solutions of all four diisocyanates in the presence of S9 mix containing 30% S9 fraction. Uniformly negative results were found when the diisocyanates were dissolved in EDGE.