Dipraseodymium dizirconium heptaoxide

Endpoint summary

Description of key information

There is no experimental data available for the substance dipraseodymium dizirconium heptaoxide for the endpoints skin irritation and eye irritation. However, based on a weight of evidence approach including experimental data available for its constituents praseodymium(III,IV) oxide and zirconium dioxide, it can be concluded that the substance is not irritant to skin or eyes and does not require to be classified as a skin or eye irritant.

Key value for chemical safety assessment

Skin irritation / corrosion

Link to relevant study records

Reference

Endpoint:

skin corrosion: in vitro / ex vivo

Data waiving:

study scientifically not necessary / other information available

Justification for data waiving:

an in vitro skin irritation study does not need to be conducted because adequate data from an in vivo skin irritation study are available

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not irritating)

Eye irritation

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not irritating)

Respiratory irritation

Endpoint conclusion

Endpoint conclusion:

no study available

Additional information

Skin irritation

1. Information on praseodymium(III,IV) oxide

In the guideline study performed by Shapiro (1991; Klimisch 2), 0.5 g of the test material was applied to both an intact and abraded site on each of six New Zealand White rabbits. The sites were occluded for 24 hours, after which the patches were removed and the test sites wiped to prevent further exposure. Evaluation occurred 24 and 72 hours after exposure. With the exception of one rabbit, which exhibited very slight erythema without oedema at both the intact and abraded site at 24 hours (reversible within 72 h), all sites were clear of irritation during the test period (PDII = 0.09). This study was considered reliable with restrictions because no observations were made at 48 hours after exposure. Based on the results of this study, praseodymium(III,IV) oxide is considered not be a dermal irritant and does not require classification.

2. Information on zirconium dioxide

In a guideline study performed by The British Industrial Biological Research Association (1986; Klimisch 2), zirconium dioxide was found not to be irritating to the skin of New Zealand White rabbits. The overall irritation score was calculated to be zero and hence, it can be concluded that zirconium dioxide does not need to be classified for skin irritation.

3. Conclusion on the substance dipraseodymium dizirconium heptaoxide

Based on the results of the in vivo skin irritation studies in rabbits performed with the constituents of the substance, i.e. praseodymium(III,IV) oxide and zirconium dioxide, the substance of these two oxides is not expected to be capable of causing skin irritation in vivo either and is concluded not to be classified for this endpoint.

Eye irritation

1. Information on praseodymium(III,IV) oxide

In the guideline study performed by Shapiro (1991; Klimisch 2), 0.1 g of the test material was instilled into the left eye of six New Zealand white rabbits, with three of the treated eyes being rinsed after 30 seconds with saline. The animals were observed for 72 hours and the eyes examined at 24, 48 and 72 hours. Irritation was scored according to the method of Draize. In this study, the test item produced minimal irritation to both the unwashed and washed eyes but no classification is required under the conditions of this study in accordance with the CLP criteria.

2. Information on zirconium dioxide

In the guideline study performed by the Chemical Evaluation and Research Institute of Japan (2000; Klimisch 2), 0.1 g of yttrium zirconium oxide (test item with a low amount of yttrium oxide incorporated into the crystal lattice of zirconium dioxide) was instilled into the left eye of 3 New Zealand White rabbits. The results were calculated in terms of the Mean ocular irritation index (MOI). The test item was determined to be slightly irritating based on the AFNOR criteria, but the irritation was reversible at 72 h. It does not need to be classified for eye irritation according to the criteria of the CLP regulation. The results of this study were considered relevant for zirconium dioxide. The study was considered reliable with restrictions because no scores for each individual eye irritation endpoint for each individual animal were reported.

3. Conclusion on the substance dipraseodymium dizirconium heptaoxide

Based on the results of the in vivo eye irritation studies in rabbits performed with praseodymium(III,IV) oxide and yttrium zirconium oxide (i.e. zirconium dioxide with a small amount of yttrium oxide incorporated into its crystal lattice), the substance is not expected to be capable of causing eye irritation in vivo to an extent requiring classification for this endpoint either.

Justification for classification or non-classification

The substance dipraseodymium dizirconium heptaoxide does not need to be classified for skin or eye irritation based on the experimental results available for its constituents praseodymium(III,IV) oxide and zirconium dioxide (or zirconium dioxide with a small amount of yttrium oxide incorporated in its crystal lattice).

No data are available for respiratory irritation.