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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.

The new ECHA CHEM database has been released by ECHA, and it now contains all REACH registration data. There are more details on the transition of ECHA's published data to ECHA CHEM here.

Diss Factsheets

Administrative data

Key value for chemical safety assessment

Genetic toxicity in vitro

Description of key information

No genotoxicity was observed in the bacterial gene mutation studies with the category members 3-MPA, iOMP and MMP. Therfore iC13MP is predicted to not show genotoxicity in bacteria.

Link to relevant study records
Reference
Endpoint:
in vitro gene mutation study in bacteria
Type of information:
read-across based on grouping of substances (category approach)
Adequacy of study:
key study
Justification for type of information:
There are no relevant variations in qualitative properties among source substances and the same potency is predicted for all target substances. This is Scenario 4 of the RAAF1. Substances MMP, BuMP, EHMP, iOMP, iC13MP, and ODMP are different alkyl esters of a common acid, 3-mercaptopropionic acid (3-MPA).
This scenario covers the category approach for which the read-across hypothesis is based on the assumption, that toxicity of compounds in this category are driven by a common toxophore. This approach serves to use existing data on genotoxicity, acute toxicity, repeated-dose toxicity and reproductive toxicity endpoints for substances in this category. For the REACH information requirement under consideration, the property investigated in studies conducted with different source substances is used to predict the property that would be observed in a study with the target substance if it were to be conducted. Similar properties are observed for the different source substances; this may include absence of effects for every member of the category.
There are differences in strength of the effects forming a regular pattern. This corresponds to Scenario 4 of the RAAF. The substances MMP, BuMP, EHMP, iOMP, iC13MP, and ODMP are esters of a common acid, 3-mercaptopropionic acid (3-MPA). All category members share the same mercaptopropionic acid moiety with one free SH group per MPA unit. The MPA unit with free SH is a prerequisite for this category.
The observed differences in effect levels (higher effect levels with increasing carbon chain length were observed in the available acute oral toxicity studies) are assumed to be mainly due to differences in molecular weight (corrections will be made for these differences) and decreasing bioavailability with increasing carbon chain length (no corrections are made for this effect; a worst-case approach is applied here, since based on the available data no exact quantification for bioavailability differences is possible at the moment).
It can be predicted with high confidence that the substances within this category will lead to the same type of effects. The main driver for toxicity is the free SH group of the MPA moiety.
Beside structural similarities and the common toxophore, the MPA moiety, category members are also likely to have similar metabolites. As explained in the Toxicokinetics section, substances are predicted to be rapidly hydrolysed into 3-MPA and the respective alcohol after absorption. According to low toxicity of the corresponding alcohols (Table 8), this would support the role of the MPA moiety as toxophore, as well as propose scenario 3 of the RAAF as applicable for this category approach. However, no experimental toxicokinetic data to support this hypothesis are available by now. To proof this hypothesis, simulated gastric acid hydrolysis studies, as well as in-vitro metabolism studies using liver microsomes will be conducted. Based on the results of these studies, scenario selection will be revaluated.
Reason / purpose for cross-reference:
read-across: supporting information
Reason / purpose for cross-reference:
read-across source
Reason / purpose for cross-reference:
read-across source
Key result
Species / strain:
E. coli WP2 uvr A
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
cytotoxicity
Remarks:
> 1.0µl/l (+S9)
Vehicle controls validity:
valid
Untreated negative controls validity:
valid
Positive controls validity:
valid
Key result
Species / strain:
S. typhimurium TA 1535
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
no cytotoxicity
Vehicle controls validity:
valid
Untreated negative controls validity:
valid
Positive controls validity:
valid
Key result
Species / strain:
S. typhimurium TA 1537
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
no cytotoxicity
Vehicle controls validity:
valid
Untreated negative controls validity:
valid
Positive controls validity:
valid
Key result
Species / strain:
S. typhimurium TA 1538
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
no cytotoxicity
Vehicle controls validity:
valid
Untreated negative controls validity:
valid
Positive controls validity:
valid
Key result
Species / strain:
S. typhimurium TA 98
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
no cytotoxicity
Vehicle controls validity:
valid
Untreated negative controls validity:
valid
Positive controls validity:
valid
Key result
Species / strain:
S. typhimurium TA 100
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
no cytotoxicity
Vehicle controls validity:
valid
Untreated negative controls validity:
valid
Positive controls validity:
valid
Conclusions:
The category members 3-MPA and MMP showed negative results in the tested bacteria strains in bacterial reverse mutation assays. Based on the category approach, iC13MP is considered to be non-genotoxic in bacteria.
Endpoint conclusion
Endpoint conclusion:
no adverse effect observed (negative)

Genetic toxicity in vivo

Endpoint conclusion
Endpoint conclusion:
no study available

Additional information





The entirety of eventually available genotoxicity data in combination with the absence of structural alerts for genotoxicity in this category will be used to strengthen the weight of the evidence for non-genotoxicity.


As Toxikokinetic literature data indicate that after absorption rapid ester hydrolysis accurs to all category members, toxicokinetic in vitro studies are planned to gain better insight on toxicokinetic properties of the substances. Depending on the results of metabolism and simulated gastric acid hydrolysis studies, scenario selection will be revaluated.





Justification for classification or non-classification