Lanthanum trinitrate

Endpoint summary

Key value for chemical safety assessment

Skin sensitisation

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not sensitising)

Additional information:

Skin sensitisation:

The potential for skin sensitisation of lanthanum trinitrate was evaluated using the local lymph node assay in the mouse (Henzell G, 2013).

according to OECD 429 guideline and EU method B.42. Following the results of preliminary study, three groups, each of four animals, were treated with the test item to dorsal ear surface as a suspension in dimethylformamide at concentrations of 10, 5 and 2.5% w/w. At concentrations of 5% and 10% w/w the stimulation indices were only slightly higher than the three-fold increase in 3HTdR incorporation compared to the control values (3.15 and 3.26 respectively). It was also observed that the preliminary screening animals showed excessive or elevated increases in ear thickness changes, indicating irritation potential. On this basis the test item could not be clearly classified as a sensitiser.

This study has been scored Klimisch 2 to reflect the ambiguity of the results (expert judgment) and the use of this study in a 'weight-of-evidence' approach according to the ECHA Practical guidance 2 'How to report weight of evidence'. Thus, the guideline indicates that a 'weight-of-evidence' approach should be used when several studies are available which give conflicting results.

In order to clarify the skin sensitisation potential of lanthanum trinitrate, a Guinea Pig Maximisation test (Török-Bathó M, 2013) was performed according to the OECD guideline 406, EU Method B.6 and EPA OPPTS 870.2600. The test item, formulated in saline solution, was applied to twenty animals per dose in the induction exposure phase (intra-dermal and dermal exposure). The dose for the intra-dermal injection was 0.01% (w/v) and 100% (w/v) for the dermal occlusive exposure. Fourteen days later, ten treated animals and five control animals were treated with the test item at a concentration of 100% (w/v). Remaining ten tested animals and five control animals were treated with 0.5 mL of the 50% dilution (safeguard dose). There were no dead animals and no local skin effects or adverse clinical responses, related to treatment, observed in either the test group or in the control group. There were no notable differences in bodyweights between the test animal group and the control group. The net response value represented an incidence rate of 0% after a challenge exposure at both 100 and 50% (w/v) lanthanum trinitrate. On the basis of the results of this study, the substance should be considered not to be a skin sensitiser.

Migrated from Short description of key information:

Skin sensitisation:

Lanthanum trinitrate was tested using the LLNA method (OECD 429 and EU Method B42 and in compliance with GLP). The substance was tested at 10%, 5% and 2.5% (w/w) concentrations. Based on the results of this K2 study (Henzell, 2013), the test result was considered inconclusive and then disregarded. Therefore, a Guinea pig maximisation test (GPMT) following OECD guideline 406, EU Method B.6 and US EPA OPPTS 870.2600, and in compliance with GLP, was performed. The result of this K1 test (Török-Bathó, 2013) concluded that this substance is clearly not a skin sensitiser.

Justification for selection of skin sensitisation endpoint:

Although this endpoint is covered by 'weight-of-evidence' approach, only the results of one of the two studies available are considered reliable.

Respiratory sensitisation

Endpoint conclusion

Endpoint conclusion:

no study available

Justification for classification or non-classification

Based on the results of the guinea pig maximisation (Magnusson and Kligman method; OECD 406) study and according to the criteria of the DSD and CLP Regulation, lanthanum trinitrate should not be classified as skin sensitiser.