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Toxicological information

Skin sensitisation

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Administrative data

Endpoint:
skin sensitisation: in vivo (LLNA)
Type of information:
experimental study
Adequacy of study:
key study
Study period:
2010-04-26 to 2010-05-12
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2010
Report date:
2010

Materials and methods

Test guideline
Qualifier:
according to guideline
Guideline:
OECD Guideline 429 (Skin Sensitisation: Local Lymph Node Assay)
Version / remarks:
2002-04-24
Deviations:
no
GLP compliance:
yes (incl. QA statement)
Remarks:
signed 2009-04-06
Type of study:
mouse local lymph node assay (LLNA)

Test material

Constituent 1
Chemical structure
Reference substance name:
Cobalt oxide
EC Number:
215-154-6
EC Name:
Cobalt oxide
Cas Number:
1307-96-6
Molecular formula:
CoO
IUPAC Name:
oxocobalt
Details on test material:
- Name of test material (as cited in study report): Cobalt Monoxide (CoRC Study EFF18)
- Chemical name: Cobalt (II) oxide
- Physical state at room temperature: powder; green-brown colour
- Storage condition of test material: At room temperature, protected from light
- Volatile: No
- Water solubility at 37 °C: 3.27 mg/L
- Stability in container after opening: Stable

In vivo test system

Test animals

Species:
mouse
Strain:
CBA
Sex:
female
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: Harlan Winkelmann, 33178 Borchen, Germany
- Age at study initiation: 8 - 9 weeks
- Weight at study initiation: 17 - 22 g
- Housing: Full barrier in an air-conditioned room; The animals were kept in groups of 5 animals in IVC cages, type II L, polysulphone cages on Altromin saw fibre bedding (lot no. 291109, preliminary test; 101109, main test)
- Diet (ad libitum): Altromin 1324 maintenance diet for rats and mice (lot no. 1130)
- Water (ad libitum): Tap water, sulphur acidified to a pH value of approx. 2.8 (drinking water, municipal residue control, microbiological controls at regular intervals).
- Acclimation period: At least five days

ENVIRONMENTAL CONDITIONS
- Temperature: 22 +/- 3°C
- Relative humidity: 55 +/- 10 %
- Air changes: At least 10 X / hour
- Photoperiod (hrs dark / hrs light): 12/12
No further information on the test animals was stated.

Results and discussion

Positive control results:
A stimulation index of 5.1 +/- 0.9 was obtained. Please "Attached background material" for the results.

In vivo (LLNA)

Resultsopen allclose all
Parameter:
EC3
Test group / Remarks:
37.5 % of the test item
Remarks on result:
other: EC3 derived by linear interpolation
Parameter:
SI
Value:
3.4
Test group / Remarks:
50 % of the test item
Parameter:
SI
Value:
2.6
Test group / Remarks:
25 % of the test item
Parameter:
SI
Value:
1.8
Test group / Remarks:
12.5 % of the test item

Any other information on results incl. tables

All animals survived throughout the test period without showing any clinical signs.

All animals showed th expected weight development, which includes a weight loss of up to 2 g throughout the study.

Applicant's summary and conclusion

Interpretation of results:
Category 1B (indication of skin sensitising potential) based on GHS criteria
Conclusions:
Solutions or preparations containing more than 37.5 % cobalt monoxide (CoRC Study EFF18) are expected to have a stimulation index of >3, and are therefore considered to be dermal sensitisers.
According to the EC Regulation No. 1272/2008 and subsequent regulations, the test item is classified as Category 1B.