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Administrative data

Description of key information

A GLP guideline study according to OECD 422 was conducted. No adverse effects were observed after oral administration of the source substance tantalum pentachloride in male and female Wistar rats at the highest tested dose of 1000 mg/kg bw/day. Based on the results, the NOAEL can be considered to be 1000 mg/kg bw/day.

Supporting data was obtained from a non-GLP, non-guideline subacute repeated inhalation toxicity study. The result of this study showed that the inhalation of tantalum pentoxide does not lead to specific changes of the lung tissues and no systemic toxicity was observed. Nevertheless, in some animals haemorrhagic infarcts caused by prolonged dust application were observed. The lesions were attributed to particle effects and are not considered substance specific.

Key value for chemical safety assessment

Repeated dose toxicity: via oral route - systemic effects

Endpoint conclusion
Endpoint conclusion:
no adverse effect observed
Dose descriptor:
NOAEL
1 000 mg/kg bw/day
Study duration:
subacute
Species:
rat
Quality of whole database:
High.

Repeated dose toxicity: inhalation - systemic effects

Endpoint conclusion
Endpoint conclusion:
no adverse effect observed
Dose descriptor:
NOAEC
150 mg/m³
Study duration:
subacute
Species:
rat

Repeated dose toxicity: inhalation - local effects

Endpoint conclusion
Endpoint conclusion:
no adverse effect observed
Dose descriptor:
NOAEC
150 mg/m³
Study duration:
subacute
Species:
rat

Repeated dose toxicity: dermal - systemic effects

Endpoint conclusion
Endpoint conclusion:
no study available

Repeated dose toxicity: dermal - local effects

Endpoint conclusion
Endpoint conclusion:
no study available

Additional information

No data regarding the oral exposition is available for ditantalum pentoxide (target substance). Thus, available data from tantalum pentachloride were used in a read-across approach. Tantalum pentachloride readily hydrolyses upon contact with water releasing a considerably higher amount of tantalum ions compared to tantalum pentoxide. Thus, any resulting toxicity potential of tantalum pentachloride would also be expected to be higher. Therefore, the read across to the source substance tantalum pentachloride is adequately protective. Details on the read-across rational are provided in section 13.

In a combined repeated dose toxicity study with the reproduction/developmental toxicity screening test (OECD 422) the source substance tantalum pentachloride was administered orally (after hydrolysis and neutralization) to 10 male and female Wistar rats/dose in water by gavage at dose levels of 0, 100, 300, or 1000 mg/kg bw/day. The animals were treated with the test item formulation on 7 days per week for a period of 54 days, i.e. during 14 days of pre-mating and maximum 14 days of mating in both males and females, during the gestation period and up to post-natal day 3 in females. Males were dosed after the mating period until the minimum total dosing period of 28 days was completed. No adverse effects of tantalum pentachloride were found up to the dose level of 1000 mg/kg body weight/day. Thus, the NOAEL in this study is considered to be 1000 mg/kg bw/day.

Supporting data addressing inhalation was obtained from a non-GLP, non-guideline sub-acute repeated inhalation toxicity study conducted in rats with tantalum pentoxide. The result of this study showed that the inhalation of tantalum pentoxide does not lead to specific changes of the lung tissues and furthermore no systemic toxicity was described. Nevertheless, in some animals haemorrhagic infarcts caused by prolonged dust application were observed. The lesions were attributed to particle effects. Thus, the effect is not considered relevant for the toxicological assessment of the target substance as the effect is not driven by substance specific properties.


Justification for selection of repeated dose toxicity via oral route - systemic effects endpoint:
GLP study in accordance to OECD guideline 422

Justification for selection of repeated dose toxicity inhalation - systemic effects endpoint:
Supporting study, in which tantalum pentoxide was tested.

Justification for selection of repeated dose toxicity inhalation - local effects endpoint:
Supporting study, in which tantalum pentoxide was tested.

Justification for classification or non-classification

Based on the available data from the read-across partner tantalum pentachloride and itself, the target substance tantalum pentoxide does not warrant classification for specific target organ toxicity in accordance to CLP as no severe toxic effects were observed.