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Toxicological information

Endpoint summary

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Description of key information

Key value for chemical safety assessment

Skin sensitisation

Endpoint conclusion
Endpoint conclusion:
no adverse effect observed (not sensitising)
Additional information:

A Buehler test conducted in 20 female guinea pigs demonstrates a negative result (BASF 1997). A non-irritating substance formulation (50% in water) was used for dermal inductions. According to OECD 406 mild to moderate skin irritation is the prerequisite for this method. If undiluted substance does not cause irritation, a negative result can be used for risk assessment. If a dilution is applied uncertainty remains whether or not undiluted substance would cause the adequate irritation and subsequent sensitization. However, the result suggests a lack of a strong skin sensitisation potential of NTA

The negative result of patch tests with 66 volunteers (Nixon 1971) is not considered to be of sufficient evidence that the substance has no sensitizing potential. The study is based on a rather limited number of participants and used 1% liquid detergent containing 20% Na3NTA. On the other hand, there exist no human case reports which point to a potential of NTA to cause skin sensitisation.

In addition to the study reports there are information supporting a lack of sensitizing potential of NTA. The bioavailability is limited as demonstrated in a recent dermal penetration study in vitro (BASF, 2007). According to a DerekfW prediction (cited in EU RAR draft 2008), the chemical reactivity and so the binding to proteins is limited. This prediction at its own is has limited weight, because negative findings usually have to be considered out of the applicability domain. However, viewing the alerts present in DerekfW this type of chemicals may be considered negative. Protein binding is considered limited, because the ester-salt is not activated and the amine is tertiary which may be sterically hindered. This conclusion is supported by a TOPKAT models. NTA is within the TOPKAT domain and provides an analogue which is negative. Despite the uncertainty due to a lack of mechanistic reasoning, the analogue approach can add to the overall impression that the chemical is not a sensitizer.


Migrated from Short description of key information:
A Bühler test according to OECD 406 was conducted in 20 female guinea pigs. 50% Na3NTA did not cause sensitization (BASF 1997).
A closed patch test study was carried out with 66 volunteers. 1% aqueous solution of a liquid detergent containing 20% Na3NTA was applied three times a week for three consecutive weeks. No evidence of sensitization was noted.
According to DerekfW the chemical reactivity and so the binding to proteins is limited.
The TOPKAT models provide an analogue which is negative.

Respiratory sensitisation

Endpoint conclusion
Additional information:

no data


Migrated from Short description of key information:
no data

Justification for classification or non-classification

Overall, it can be concluded that there is no evidence of a skin sensitising potential for NTA.