Registration Dossier

Administrative data

Description of key information

Key value for chemical safety assessment

Skin sensitisation

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

Antimony as a semi-metal is subject at its surface to a passivation by the formation of a layer of antimony trioxide. In particular for antimony metal powder because of its large surface area, the oxide layer will form a quantitatively relevant portion of the entire particle. Furthermore, in vitro bioaccessibility testing in various artificial body fluids has shown that antimony metal compared to diantimony trioxide has a similar release rate of antimony ions (please refer to the respective entry under the endpoint toxicokinetics).

In view of this, and since transformation / dissolution testing (CanMet, 2010) has shown that antimony metal may be expected to release trivalent antimony ions upon dissolution, it may be assumed that human exposure towards antimony metal is secondary to that of antimony trioxide. Thus, read-across for sensitisation is considered justified.

There is a complete absence of any human studies of adequate quality that can be used for assessing the sensitising potential of diantimony trioxide. However, there is one reliable animal study (Chevalier, 2005), performed according to TG 406 and GLP, which shows that diantimony trioxide has no sensitising properties.

Diantimony trioxide (and via read-across also antimony metal) is not a skin sensitiser.

Respiratory sensitisation

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

Antimony as a semi-metal is subject at its surface to a passivation by the formation of a layer of antimony trioxide. In particular for antimony metal powder because of its large surface area, the oxide layer will form a quantitatively relevant portion of the entire particle. Furthermore, in vitro bioaccessibility testing in various artificial body fluids has shown that antimony metal compared to diantimony trioxide has a similar release rate of antimony ions (please refer to the respective entry under the endpoint toxicokinetics).

In view of this, and since transformation / dissolution testing (CanMet, 2010) has shown that antimony metal may be expected to release trivalent antimony ions upon dissolution, it may be assumed that human exposure towards antimony metal is secondary to that of antimony trioxide. Thus, read-across for sensitisation is considered justified.

Based on an industry survey, during many years of industrial practice no cases of hypersensitivity were observed till now by workers exposed exclusively to diantimony trioxide.

Diantimony trioxide (aand via read-across also antimony metal) is not a respiratory sensitiser.

Justification for classification or non-classification

Sensitisation:

 

The reference Chevalier F. (2005), is considered as the key study on skin sensitisation and will be used for classification. The overall sensitisation results are as follows:

 

Moore, G.E.(1994) – Buehler method in guinea pigs

The incidence of sensitisation after the challenge application was 0/20. Thus, the classification criteria according to regulation (EC) 1272/2008 as skin sensitizer are not met since 0 % of the test animals responded.

 

Respiratory sensitisation:

Based on an industry survey, during many years of industrial practice no cases of hypersensitivity were observed till now by workers exposed exclusively to diantimony trioxide. Thus, no classification as respiratory sensitiser according to regulation (EC) 1272/2008 is required.