Methylidynetri-p-phenylene triisocyanate

Endpoint summary

Additional information

In vitro gene mutation study in bacteria:

Triphenylmethane-4,4',4''-triisocyanate (tested as a 27% solution in ethyl acetate) was evaluated in an Ames Test on Salmonella typhimurium strains TA 1535, TA 100, TA, 1537, TA 98, and TA 102, performed according to OECD TG 471 up to concentrations of 5000 µg per plate. Doses up to and including 5000 mg per plate did not cause any bacteriotoxic effects, but precipitation startet at the dose 1581 µg per plate. No biologically relevant increase in the mutant count, in comparison with negative controls, was observed. The positive controls had a marked mutagenic effect. Therefore Triphenylmethane-4,4',4''-triisocyanate was considered to be non-mutagenic without and with S9 mix in the plate incorporation as well as in the preincubation modification of the Salmonella/microsome test.

In vitro micronucleus study:

Triphenylmethane-4,4',4''-triisocyanate (tested as a 27% solution in ethyl acetate) was examined for mutagenic activity (chromsome breakage and misdistribution of chromosomes) in the in vitro micronucleus test using Chinese Hamster V79 cells in accordance to OECD Guideline 487. The negative control and appropriate positive controls with known mutagens demonstrated the suitability and sensitivity of the test system. The test item showed no biologically relevant increase in the frequency of micronucleus containing V79 cells in the absence (both pulse and continuous treatment) or in the presence of S9 mix (pulse treatment) when tested up to precipitating concentrations.

In vitro gene mutation study in mammalian cells

Triphenylmethane-4,4',4''-triisocyanate (tested as a 27% solution in ethyl acetate) was tested in an in vitro gene mutation assay in V79 cells (HPRT) according to OECD TG 476 in concentrations of up to and including 1000 µg/mL with and without metabolic activation. The negative control and appropriate positive controls with known mutagens demonstrated the suitability and sensitivity of the test system. The test item showed no biologically relevant increase in the frequency of mutations in the absence or in the presence of S9 mix. Since up to concentrations were tested, that caused phase separation, Triphenylmethane-4,4',4''-triisocyanate is considered to be non-mutagenic in the in vitro gene mutation assay.

Justification for selection of genetic toxicity endpoint
No study was selected since all three in vitro mutagenicity studies were negative.

Endpoint Conclusion: No adverse effect observed (negative)

Justification for classification or non-classification

Based on the available study results (negative in Ames test, HPRT test and micronucleus test, in vitro) a classification according to EU-Directive 67/548/EEC, Annex VI and according to Regulation (EC) No 1272/2008, Annex I is not warranted.