Registration Dossier

Toxicological information

Skin irritation / corrosion

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Administrative data

Endpoint:
skin irritation: in vivo
Type of information:
experimental study
Adequacy of study:
key study
Study period:
1990-07-10 to 1990-07-13
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1990
Report Date:
1990

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 404 (Acute Dermal Irritation / Corrosion)
Version / remarks:
adopted 12 May 1981
Deviations:
yes
Remarks:
the test substance only was applied to 2.5 cm square of skin instead to approximately 6 cm square of skin
GLP compliance:
yes
Remarks:
The study report states that the study was conducted in compliance with Good Laboratory Practice Standards, e.g. by the United Kingdom Compliance Programme, Department of Health & Social Security 1986 and subsequent revision, Department of Health, 1989.

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
- Name of test material (as cited in study report): pure molybdic oxide
- Physical state: light grey powder
- Analytical purity: > 99.9 % (calculated based on a Molybdenum content of 66.63 %)
- Impurities (identity and concentrations): no relevant impurities (> 1.0%)
- Purity test date: 1990-06-06
- Stability under test conditions: not determined
- Storage condition of test material: at ambient temperature

No further significant information on test material was stated.

Test animals

Species:
rabbit
Strain:
New Zealand White
Details on test animals and environmental conditions:
TEST ANIMALS
- Age at study initiation: approximately 9 to 11 weeks
- Weight at study initiation: weight range 2.1 to 2.6 kg
- Housing: The rabbits were individually housed in metal cages with perforated floors.
- Diet: free access to SDS Standard Rabbit Diet
- Water: free access to tap water
- Acclimation period: The rabbits were all acclimated to the laboratory environment, but the acclimatisation period was not stated.

ENVIRONMENTAL CONDITIONS
- Temperature: maintained at approximately 19 °C
- Relative humidity: 30-70 %
- Air exchanges: maintained at approximately 19 air changes per hour
- Photoperiod (hrs dark / hrs light): 12 hrs/12 hrs

No further significant information on test animals was stated.

Test system

Type of coverage:
semiocclusive
Preparation of test site:
shaved
Vehicle:
water
Controls:
not required
Amount / concentration applied:
TEST MATERIAL
- Amount(s) applied (volume or weight with unit): 0.5 g amount of Pure Molybdic oxide

VEHICLE
- Amount(s) applied (volume or weight with unit): 0.5 ml distilled water

No further significant information was stated.
Duration of treatment / exposure:
4 hour period
Observation period:
Examination of treated skin was made on Day 1 (i.e. approximately 30 minutes after removal of the patches) and on Days 2, 3 and 4. All animals were observed daily for signs of ill health or toxic signs.
Number of animals:
6 female rabbits
Details on study design:
TEST SITE
- Area of exposure: Approximatley 24 hours prior to application of the test substance, hair was removed with electric clippers from the dorso-lumbar region of each rabbit exposing an area of skin approximately 10 cm square.
- Type of wrap if used: A 2.5 cm square gauze pad was used. each treatment site was occluded with "Elastoplast" elastic adhesive dressing.

REMOVAL OF TEST SUBSTANCE
- Washing: The treament site was washed using water to remove any residual test substance.
- Time after start of exposure: At the end of the exposure period (Exposure period. 4 hours)

SCORING SYSTEM:
Grading and scoring of the dermal reactions were performed using the prescribed numerical scoring system as follows:

Erythema and eschar formation:
No erythema = 0
Very slight erythema (barely perceptible) = 1
Well-defined erythema = 2
Moderate to severe erythema = 3
Severe erythema (beet redness) to slight eschar formation (injuries in depth) = 4

Oedema formation:
No oedema = 0
Very slight oedema (barely perceptible) = 1
Slight oedema (edges of area well-defined by definite raising) = 2
Moderate oedema (raised approximately 1 millimetre) = 3
Severe oedema (raised more than 1 millimetre and extending beyond the area of exposure) = 4

No further significant information on study design was stated.

Results and discussion

In vivo

Resultsopen allclose all
Irritation parameter:
erythema score
Basis:
mean
Time point:
other: Day 1 (i.e., approimately 30 minutes after removal of the patches) and on Days 2, 3 and 4
Score:
0
Max. score:
0
Remarks on result:
other: No response to treatment in any animal throughout the observation period.
Irritation parameter:
edema score
Basis:
mean
Time point:
other: Day 1 (i.e. approximately 30 minutes after removal of the patches) and on Days 2, 3 and 4
Score:
0
Max. score:
0
Remarks on result:
other: No response to treatment in any animal throughout the observation period.
Irritant / corrosive response data:
There was no response to treatment in any animal throughout the observation period.
Other effects:
no data

Applicant's summary and conclusion

Interpretation of results:
not irritating
Remarks:
Migrated information Criteria used for interpretation of results: EU
Conclusions:
A single semi-occlusive application of molybdenum trioxide to intact rabbit skin for four hours elicited no dermal irritation.
Molybdenum trioxide does not require classification as a skin irritant according to directive 67/548/EEC or regulation 1272/2008/EC.