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Toxicological information

Skin sensitisation

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Administrative data

Endpoint:
skin sensitisation: in vivo (non-LLNA)
Type of information:
experimental study
Adequacy of study:
key study
Study period:
1993-03-31 to 1996-01-23
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1996
Report Date:
1996

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 406 (Skin Sensitisation)
Deviations:
no
GLP compliance:
yes
Type of study:
guinea pig maximisation test
Justification for non-LLNA method:
Suitable non-LLNA data was already available. Therefore the generation of new LLNA data is not necessary.

Test material

Reference
Name:
Unnamed
Type:
Constituent
Specific details on test material used for the study:
- Name of test material (as cited in study report): Sodium molybdate 241/32
- Physical state: white powder
- Analytical purity: 40.52% molybdenum, 19.29% sodium
- Purity test date: 1993-05-13
- Batch No.: 241/32
- Storage condition of test material: room temperature

In vivo test system

Test animals

Species:
guinea pig
Strain:
Dunkin-Hartley
Sex:
female
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: D. Hall, Newchurch, Staffordshire, England
- Age at study initiation: 6 to 7 weeks
- Weight at study initiation: 286 to 377 g
- Housing: in groups of 10 in suspended metal cages with wire mesh floors
- Diet (e.g. ad libitum): ad libitum
- Water (e.g. ad libitum): ad libitum
- Acclimation period: 4 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 21 °C
- Humidity (%): 30 to 70 %
- Air changes (per hr): 15
- Photoperiod (hrs dark / hrs light): 12/12

Study design: in vivo (non-LLNA)

Inductionopen allclose all
Route:
intradermal
Vehicle:
water
Concentration / amount:
5 % (w/w) / 0.1 mL
Route:
intradermal
Vehicle:
other: Freund´s complete adjuvant
Concentration / amount:
50/50 mixture of Freund`s complete adjuvant and water for irrigation
Route:
intradermal
Vehicle:
water
Concentration / amount:
5% (w/w) in a 50/50 mixture of Freund´s complete adjuvant and water for irrigation
Route:
epicutaneous, occlusive
Vehicle:
water
Concentration / amount:
70% (w/w)
Adequacy of induction:
non-irritant substance, but skin pre-treated with 10% SDS
Challengeopen allclose all
No.:
#1
Route:
epicutaneous, occlusive
Vehicle:
water
Concentration / amount:
70% (w/w) applied to the anterior site
No.:
#1
Route:
epicutaneous, occlusive
Vehicle:
water
Concentration / amount:
35% (w/w) applied to the posterior site
No. of animals per dose:
20
Details on study design:
RANGE FINDING TESTS:
- 2 guinea-pigs
- Intradermal injection: 0.1, 0.25, 0.5, 1.0, 2.5, 5.0, 7.5 and 10.0 % w/w sodium molybdate 241/32 in water and vehicle control
- Epicutaneous application: 30, 50, 60 and 70 % w/w sodium molybdate 241/32 in water

MAIN STUDY
A. INDUCTION EXPOSURE
- No. of exposures: 1x intradermal, 1x epicutaneous
- Exposure period: 48 h of occlusive topical application
- Test groups: 1
- Control group: 2
- Site: 40 x 60 mm area of dorsal skin on the scapular region

Control and test animals were challenged topically two weeks after the topical induction

B. CHALLENGE EXPOSURE
- No. of exposures: 1
- Exposure period: 24 h
- Test groups: 1
- Control group: 1
- Site: 20 x 20 mm patch applied to both anterior and posterior flank sides
- Concentrations: saturated Whatman No. 3 paper with 0.2 ml of Sodium molybdate 241/32 either 70 % (anterior) or 35 % (posterior) w/w in water
- Evaluation (hr after challenge): 24, 48 and 72 hours after removal of the patches

OTHER:
The preliminary investigations indicated, that topical application of 70 % w/w sodium molybdate 241/32 in water did not cause skin irritation. Therefore, six days after the intradermal injections, the same 40 x 60 mm area was clipped and shaved free of hair and the site was pre-treated by gentle rubbing with 0.2 mL per site of 10 % w/w sodium lauryl sulphate in petrolatum. 24 hours later a 20 x40 mm patch of Whatman No. 3 paper was saturated with 0.4 mL of Sodium molybdate 241/32, 70% w/w in distilled water. The patch was placed on the skin under occlusive conditions and left in place for 48 hours.
Challenge controls:
Animals that were treated the same way like test animal for the procedure of induction with the exception that the sodium molylbdate 241/32 was omitted. The challenge procedure was likewise to the test animals.
Positive control substance(s):
yes
Remarks:
formalin

Results and discussion

Positive control results:
Sensitivity of the guinea-pig strain used is checked periodically with formalin, a known sensitiser. Formalin produced a clear positive response in all performed control experiments.

In vivo (non-LLNA)

Resultsopen allclose all
Key result
Reading:
1st reading
Hours after challenge:
24
Group:
test group
Dose level:
70 and 35 % Sodium molybdate 241/32 w/w in water
No. with + reactions:
0
Total no. in group:
20
Clinical observations:
none
Remarks on result:
no indication of skin sensitisation
Key result
Reading:
2nd reading
Hours after challenge:
48
Group:
test group
Dose level:
70 and 35 % of Sodium molybdate 241/32 w/w in water
No. with + reactions:
0
Total no. in group:
20
Clinical observations:
none
Remarks on result:
no indication of skin sensitisation
Key result
Reading:
other: 3rd reading
Hours after challenge:
72
Group:
test group
Dose level:
70 and 35 % Sodium molybdate 241/32 w/w in water
No. with + reactions:
0
Total no. in group:
20
Clinical observations:
none
Remarks on result:
no indication of skin sensitisation
Reading:
1st reading
Hours after challenge:
24
Group:
negative control
Dose level:
Freud's treated control
No. with + reactions:
0
Total no. in group:
20
Clinical observations:
none
Remarks on result:
no indication of skin sensitisation
Reading:
other:
Group:
positive control
Dose level:
Formalin (Induction: Intradermal 0.1% , topical 10 % aqueous dilution)
No. with + reactions:
10
Total no. in group:
10
Remarks on result:
positive indication of skin sensitisation

Any other information on results incl. tables

Clinical signs:

No signs of toxicity were recorded.

Induction:

- Intradermal injections: Necrosis was recorded at sites receiving Freund´s Complete Adjuvant in test and control animals. A slight irritation was seen in test animals at sites receiving Sodium molybdate, 5% w/w in water for irrigation; no irritation was observed in the control animals receiving water for irrigation.

- Topical application: Slight erythema was observed in test animals following topical application with Sodium molybdate 241/32, 70% w/w in distilled water. Very slight erythema was seen in the control guinea-pigs.

Applicant's summary and conclusion

Interpretation of results:
GHS criteria not met
Conclusions:
In conclusion, Sodium molybdate 241/32 is considered as not skin sensitising.
Executive summary:

In a dermal sensitization study (OECD 406) with Sodium molybdate in water, 20 young adult female guinea-pigs of the Dunkin-Hartley strain were tested using the method of Magnusson and Kligman. No dermal reactions were seen in a period of 72 hours after challenging the test animals. In this study, Sodium molybdate is not a dermal sensitizer.