Trometamol

Endpoint summary

Key value for chemical safety assessment

Genetic toxicity in vitro

Description of key information

A bacterial mutagenicity test employing genetically modified E. coli was negative with trometamol, with and without S9-mix. Based on read-across within an analogue approach (AEPD), trometamol is considered to be not genotoxic in 3 in vitro mutagenicity assays. Gene mutation (bacterial reverse mutation assay / Ames test): S. typhimurium TA 1535, TA 1537, TA 98, TA 100 and E. coli WP2 uvrA: negative with and without metabolic activation (according to OECD 471); chromosome aberration (in vitro mammalian chromosome aberration test): negative with cultured Chinese hamster lung cells with and without metabolic activation (according to OECD 473); gene mutation (mammalian cell gene mutation test): negative with Chinese hamster ovary cells with and without metabolic activation (according to OECD 476). 

Endpoint Conclusion: No adverse effect observed (negative)

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (negative)

Genetic toxicity in vivo

Endpoint conclusion

Endpoint conclusion:

no study available

Additional information

A bacterial mutagenicity test employing genetically modified E. coli was negative with 2-amino-2-(hydroxymethyl)-1,3-propanediol (trometamol) in the presence and the absence of a metabolic activation system (Hayes et al., 1984). The test results were obtained with one E.coli test strain that was transiently exposed to, and then removed from trometamol (1 mg/mL, pH 7.4) prior to the selection step for mutant cells. There are no further data available on genetic toxicity of trometamol.

There are three in vitro genetic toxicity studies available using the analogue substance AEPD, conducted according to OECD guidelines: a bacterial reverse mutation assay (Ames test), an in vitro chromosomal aberration test in Chinese hamster lung cells and an in vitro mammalian cell mutation assay in Chinese hamster ovary cells. AEPD was investigated in a bacterial reverse mutation assay (Ames test) according to OECD 471 (Mochizuki, 2004). The pre-incubation method was conducted with S. typhimurium strains TA 1535, TA 1537, TA 98, TA 100 and E. coli WP2 uvrA at concentrations up to 5000 µg/plate. AEPD did not induce reversions in any of the S. typhimurium strains or in E. coli WP2 uvrA with or without metabolic activation. No cytotoxic effects were observed and all the positive controls were valid. In a study conducted according to OECD 473, the potential of AEPD to induce chromosomal aberrations was tested in cultured Chinese hamster lung (CHL) cells (Sono, 2004). CHL cells were exposed to AEPD at concentrations up to 1200 µg/mL. No increase in chromosomal aberrations was observed in the experiments with short-term treatment (6 h) in the presence or absence of metabolic activation. No cytotoxic effects were observed and the positive controls were valid. Because of the negative results of the short-term treatment, an additional testing without metabolic activation was performed with continuous treatment (24 and 48 h). After continuous treatment, AEPD did not induce chromosomal aberrations in CHL cells. AEPD was also tested for its potential to cause gene mutations in anin vitro mammalian cell mutation assay according to OECD 476 (Indrani, 2011). Chinese hamster ovary (CHO) cells were treated with AEPD at concentrations of up to 1192 µg/mL for 4 h both with and without metabolic activation. After an expression time of 9 days in growth medium, cells were incubated for 10 days with 6 -thioguanine as selection agent for forward mutation at the HPRT locus. Both with and without metabolic activation, no increases in mutant frequency were observed in the initial and in the confirmatory gene mutation assay. At the highest tested concentration, AEPD caused cell growth inhibition, evaluated by relative cloning efficiency.

Taking into account all the available data, AEPD showed no evidence of a clastogenic and mutagenic potential with and without metabolic activation in in-vitro test systems. The results of AEPD have been used for read-across to trometamol, based on an analogue approach. This is in accordance with Regulation (EC) 1907/2006, Annex XI, which specifies that read-across of data from a suitable substance may be used to cover data gaps. Based on the analogue approach, it can be assumed that trometamol has no genotoxic potential.  

Justification for classification or non-classification

Based on trometamol data and on read-across within an analogue approach, the available data on genetic toxicity do not meet the criteria for classification according to Regulation (EC) 1272/2008 or Directive 67/548/EEC, and are therefore conclusive but not sufficient for classification.