Registration Dossier

Administrative data

Description of key information

Sodium molybdate was tested negative for acute dermal and eye irritating properties in tests conducted according to OECD 404 and OECD 405. Sodium molybdate is used as read-across partner to Molybdenum disilicide.

Key value for chemical safety assessment

Skin irritation / corrosion

Link to relevant study records
Reference
Endpoint:
skin irritation: in vivo
Type of information:
read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
key study
Justification for type of information:
For justification of read-across please refer to the read-across report attached to IUCLID section 13.
Reason / purpose:
read-across source
Irritation parameter:
erythema score
Basis:
mean
Time point:
other: 0.5 h
Score:
0
Max. score:
0
Irritation parameter:
edema score
Basis:
mean
Time point:
other: 0.5 h
Score:
0
Max. score:
0
Irritation parameter:
erythema score
Basis:
mean
Time point:
24 h
Score:
0
Max. score:
0
Irritation parameter:
edema score
Basis:
mean
Time point:
24 h
Score:
0
Max. score:
0
Irritation parameter:
erythema score
Basis:
mean
Time point:
48 h
Score:
0
Max. score:
0
Irritation parameter:
edema score
Basis:
mean
Time point:
48 h
Score:
0
Max. score:
0
Irritation parameter:
erythema score
Basis:
mean
Time point:
72 h
Score:
0
Max. score:
0
Irritation parameter:
edema score
Basis:
mean
Time point:
72 h
Score:
0
Max. score:
0
Irritant / corrosive response data:
No irritation
Other effects:
None
Table 1: Dermal reactions elicited by Sodium Molybdate
Rabbit number*  E = Erythema Day
O = Oedema 1** 2 3 4
 
2481 E 0 0 0 0
O 0 0 0 0
2482 E 0 0 0 0
O 0 0 0 0
2483 E 0 0 0 0
O 0 0 0 0
2484 E 0 0 0 0
O 0 0 0 0
2485 E 0 0 0 0
O 0 0 0 0
2486 E 0 0 0 0
O 0 0 0 0

*= only female animals were tested

**= approximately 30 minutes after removal of dressing

Interpretation of results:
GHS criteria not met
Conclusions:
In conclusion, in an acute dermal irritation/corrosion study according to OECD 404, the read-across partner Sodium molybdate was found to be non-irritating.
Executive summary:

In a primary dermal irritation study (OECD guideline 404) six female New Zealand white rabbits were dermally exposed to 0.5 g of Sodium molybdate for 4 hours to a body surface area of 2.5 cm² under semi-occlusive conditions. Animals then were observed for 0.5, 24, 48 and 72 hours. Sodium molybdate did not cause any skin effects and is considered under the conditions of this study as non toxic.

This information is used in a read-across approach in the assessment of the target substance.

For justification of read-across please refer to the attached read-across report (see IUCLID section 13).

Endpoint conclusion
Endpoint conclusion:
no adverse effect observed (not irritating)

Eye irritation

Link to relevant study records
Reference
Endpoint:
eye irritation: in vivo
Type of information:
read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
key study
Justification for type of information:
For justification of read-across please refer to the read-across report attached to IUCLID section 13.
Reason / purpose:
read-across source
Irritation parameter:
cornea opacity score
Basis:
mean
Time point:
24/48/72 h
Score:
0
Max. score:
0
Irritation parameter:
iris score
Basis:
mean
Time point:
24/48/72 h
Score:
0
Max. score:
0
Irritation parameter:
conjunctivae score
Basis:
mean
Time point:
24/48/72 h
Score:
0.33
Max. score:
0.66
Reversibility:
fully reversible within: 3d
Irritation parameter:
chemosis score
Basis:
mean
Time point:
24/48/72 h
Score:
0.06
Max. score:
0.33
Reversibility:
fully reversible within: 2d
Irritant / corrosive response data:
Eye irritation scores were recorded at 1, 24, 48, and 72 hours, and at 7 days after treatment. No corneal damage or iridial inflammation was seen throughout the observation period. A diffuse crimson-red colouration of the conjunctivae was seen one hour after instillation only in one animal. Mild conjunctival inflammation was observed in the remaining five animals. Conjunctival reactions had completely resolved in all animals one to three days after instillation.

Table 1: Mean values of each rabbit scored at 24, 48 and 72 hours after treatment with Sodium molybdate
Animal number Opacity Iritis Conjunctival redness Conjunctival oedema
2451 (male) 0 0 0.33 0
2523 (male) 0 0 0.33 0
2524 (male) 0 0 0.66 0.33
2525(male) 0 0 0.33 0
2526 (female) 0 0 0 0
2527 (female) 0 0 0.33 0
Interpretation of results:
not irritating
Conclusions:
In conclusion, in an acute eye irritation/corrosion study according to OECD 405, Sodium molybdate is not an eye-irritant.
Executive summary:

In a primary eye irritation study (OECD 405), 100 mg of Sodium molybdate was instilled into the conjunctival sac of one eye of each of six young adult New Zealand White rabbits (four males and two females). Animals were observed for 7 days. Irritation was scored by the method of Draize. Only very mild conjunctival reactions were observed, which were fully reversible within 2-3 days. In this study, Sodium molybdate is not an eye irritant.

 

This information is used in a read-across approach in the assessment of the target substance.

For justification of read-across please refer to the attached read-across report (see IUCLID section 13).

Endpoint conclusion
Endpoint conclusion:
no adverse effect observed (not irritating)

Respiratory irritation

Endpoint conclusion
Endpoint conclusion:
no study available

Additional information

No data is available for Molybdenum disilicide (target substance). Thus, available data from Sodium molybdate was used in a read-across approach. Due to a lower water solubility of Molybdenum disilicide compared to Sodium molybdate the resulting bioavailability (toxicity potential) would also be expected to be lower. Therefore, the read across to the source substance Sodium molybdate is adequately protective. Details on the read-across rational are provided in section 13.

Sodium molybdate was tested negative for acute dermal and eye irritating properties in tests conducted according to OECD 404 and OECD 405. Based on the results from the read-across partner Sodium molybdate, Molybdenum disilicide can be considered as not irritating to the skin and eye.

Justification for classification or non-classification

The read across partner Sodium molybdate did not cause any skin and eye effects in an acute dermal and eye irritating study in accordance to OECD 404 and OECD 405. Based on the results from the read-across partner, no classification of Molybdenum disilicide is warranted.