Molybdenum nickel tetraoxide

Endpoint summary

Description of key information

- skin: Human Skin Model Test (in vitro): not irritating 
- eye: HET-CAM (in vitro): not irritating 

Key value for chemical safety assessment

Skin irritation / corrosion

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not irritating)

Eye irritation

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not irritating)

Additional information

Besides the in vitro studies on the skin and eye irritating potential of Molybdenum nickel tetraoxide, there are no in vivo data available for the substance itself. Therefore a read-across approach was conducted from the surrogate substance Nickel sulphate which also belongs to the group of soluble Nickel compounds.

 

Skin irritation

In vitro

The skin irritation potential of Molybdenum nickel tetraoxide was determined by Paulus (2010) in the Human Skin Model Test following EU-Method B.46. An average of 25.6 mg of the test item was applied to EpiDerm^TM tissues. After a 60 min incubation tissues were rinsed and incubated for further 41 hours. The cell viability was measured photometrically by dehydrogenase conversion of MTT into a blue formazan salt. No decrease of cell viability was detected compared to the negative control (DPBS-buffer). The relative absorbance values were increased to 118.5%. This value is well above the threshold for irritation potential (50%). Therefore, under these test conditions Molybdenum nickel tetraoxide is considered as to possess no skin irritation potential.

In vivo

In a GLP-guideline study according to OECD 404, 0.5 g of the read-across substance Nickel sulphate hexahydrate (moistened with water) was applied under semiocclusive conditions to the shaved skin of New Zealand White rabbits for periods of 3 minutes, 1 and 4 hours (respecitvely, for the animal with 3 exposure sites) and 4 hours (for the remaining animals with only single exposure site) (SLI, 1999). The observation period was terminated at 72 hours.

Exposure to the test article for 3 minutes and 1 hour produced no dermal irritation and very slight erythema, respectively, in one animal immediately following patch removal. The dermal irritation at the 1-hour exposure site resolved completely by the 48-hour scoring interval. An additional dermal finding of desquamation was noted on the 1-hour test site.

After exposure to the test substance for 4 hours very slight erythema on all rats were observed one hour following patch removal. The dermal irritation was fully reversible on all test animals by the 48-hour scoring interval. An additional dermal finding of desquamation was noted on 1of 3 test animals. The mean value of the scores for the 4-hour exposure period for either erythema or oedema formation calculated over all the animals tested was 0.42 and 0.00, respectively.

Therefore, under the conditions of this test, Nickel sulphate hexahydrate is not considered as skin irritant.

Eye irritation

In vitro

The eye irritancy potential of Molybdenum nickel tetraoxide was evaluated in the Hen's Egg Test - Chorioallantoic Membrane (HET-CAM) assay following ICCVAM (Paulus, 2010). 0.3 mL of the test item was added to the membrane of 9 nine day incubated Lohmannchicken eggs. The reaction on the vessels were observed over a period of 300 seconds. Molybdenum nickel tetraoxide showed no effects on the blood vessels of the CAM. The calculated mean irritation score was 0.00. Thus, it can be stated, that under these experimental conditions, Molybdenum nickel tetraoxide doses not possess irritation potential

 

In vivo

The acute eye irritation of the read-across substance Nickel sulphate hexahydrate was investigated in a GLP-guideline study (OECD Guideline 405) in New Zealand White rabbits (SLI, 1999). 0.1 g of the test substance was instilled in the right eye of a total of 3 rabbits. The left eye, which remained untreated, served as control. Ocular reactions to the substance were examined 1, 24, 48, 72 hours and 7 days after treatment. Iritis was noted in all rabbits (3/3) at the 1 hour examination. By the 48-hour scoring interval the iritis resolved completely. Conjunctivitis (redness, swelling and discharge) was noted in 3/3 test eyes at the 1-hour scoring interval. Complete recovery of the conjunctival irritation occured by day 7. Systemic toxic effects could not be detected.

Justification for classification or non-classification

The data on skin and eye irritation are conclusive but not sufficient for classification according to the criteria of Directives 67/548/EEC (DSD) and 1272/2008/EC (CLP).