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Description of key information

Key value for chemical safety assessment

Skin sensitisation

Link to relevant study records
Reference
Endpoint:
skin sensitisation: in vivo (LLNA)
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
4 (not assignable)
Rationale for reliability incl. deficiencies:
other: Data is from review article.
Qualifier:
according to guideline
Guideline:
OECD Guideline 429 (Skin Sensitisation: Local Lymph Node Assay)
GLP compliance:
not specified
Type of study:
mouse local lymph node assay (LLNA)
Species:
mouse
Strain:
CBA
Sex:
female
Vehicle:
acetone/olive oil (4:1 v/v)
Concentration:
2.5, 5, 10, 25 and 50% in acetone:olive oil (4:1 v/v)
No. of animals per dose:
2.5% -5 nulliparous and non pregnant female mouse
5%- 5 nulliparous and non pregnant female mouse
10% -5 nulliparous and non pregnant female mouse
25% -5 nulliparous and non pregnant female mouse
50% -5 nulliparous and non pregnant female mouse
Details on study design:
MAIN STUDY
A. INDUCTION EXPOSURE
- No. of exposures: 3
- Test groups: 3 groups of 5 test animals
- Control group: 5 + 5 (additional study)
- Site: epidermal
- Frequency of applications: 3
- Duration: the experimental animals were epidermally exposed to varying concentrations test chemical on three concesutive days and further testing was done three days after last exposure.
- Concentrations: 5%, 25% and 50% and additionally 2.5% and 10%
OTHER: Three days after the last exposure, all animals were injected with ³H-methyl thymidine and after five hours the draining (auricular) lymph nodes were excised.

After precipitating the DNA of the lymph node cells, radioactivity measurements were done.

Additional study: Based on the results, additional groups were treated at 2.5 and 10%. Five vehicle control animals were similarly treated, but with vehicle alone.
Positive control substance(s):
hexyl cinnamic aldehyde (CAS No 101-86-0)
Parameter:
SI
Remarks on result:
other: The SI values calculated for the substance concentrations 2.5, 5, 10 and 25% were 1.1, 1.5, 10.1, 16.4 respectively. An EC3 value of 5.8% was calculated.
Parameter:
other: disintegrations per minute (DPM)
Remarks on result:
other: see Remark
Remarks:
Mean DPM/animal values for the experimental groups treated with test substance concentrations 5 and 25 % were 232 and 2473 respectively. The DPM Value for the only surviving animal treated at 50% was 2402. The mean DPM/animal value for the vehicle control group was 151. In order to achieve more information regarding the SI=3 value, additional groups of animals were treated. Mean DPM/animal values for the experimental groups treated with test substance concentrations 2.5 and 10% were 145 and 1351 respectively. The mean DPM/animal value for the vehicle control group was 134.

Stimulation Index (SI) values:

Concentration

Stimulation Index

Test item

 

2.5%

1.1

5%

1.5

10%

10.1

25%

16.4

50%

#

Vehicle

1.0

α-hexylcinnamaldehyde

 

5%

1.2

10%

2.7

25%

16.8

# animals found dead

Interpretation of results:
sensitising
Remarks:
Migrated information Criteria used for interpretation of results: EU
Conclusions:
4-chlororesorcinol is considered as a strong skin sensitiser, as the EC3-value is found to be less than 10%, when tested as per Mouse local lymphnode assay (LLNA).
Executive summary:
Local Lymph Node Assay (LLNA) was performed on a group of 5 nulliparous and non-pregnant mice to study the skin sensitizing activity of the test materialA12 / SAT 030626 (4-Chlororesorcinol) at concentrations of 2.5, 5, 10, 25 and 50%. Vehicle control used was acetone:olive oil (4:1 v/v).

 

In the main study, three groups of five experimental animals were epidermally exposed to a 5%, 25% and 50% concentration respectively on three consecutive days. Five vehicle control animals were similarly treated, but with vehicle alone (acetone:olive oil (4:1 v/v).

 

Three days after the last exposure, all animals were injected with ³H-methyl thymidine and after five hours the draining (auricular) lymph nodes were excised.

 

After precipitating the DNA of the lymph node cells, radioactivity measurements were done.Based on the results, additional groups were treated at 2.5 and 10%. Five vehicle control animals were similarly treated, but with vehicle alone.

 

On the basis of observations noted, EC3 value of 5.8% was calculated.

According to the classification criteria for skin sensitisation, 4-chlororesorcinol is likely to be considered as a strong skin sensitiser, as the EC3-value is found to be less than 10%.

Endpoint conclusion
Endpoint conclusion:
adverse effect observed (sensitising)
Additional information:

Local Lymph Node Assay (LLNA) was performed on a group of 5 nulliparous and non-pregnant mice to study the skin sensitizing activity of the test materialA12 / SAT 030626 (4-Chlororesorcinol) at concentrations of2.5, 5, 10, 25 and 50%. Vehicle control used was acetone:olive oil (4:1 v/v).

 

In the main study, three groups of five experimental animals were epidermally exposed to a 5%, 25% and 50% concentration respectively on three consecutive days. Five vehicle control animals were similarly treated, but with vehicle alone (acetone:olive oil (4:1 v/v).

 

Three days after the last exposure, all animals were injected with ³H-methyl thymidine and after five hours the draining (auricular) lymph nodes were excised.

 

After precipitating the DNA of the lymph node cells, radioactivity measurements were done.Based on the results, additional groups were treated at 2.5 and 10%. Five vehicle control animals were similarly treated, but with vehicle alone.

 

On the basis of observations noted, EC3 value of 5.8% was calculated.

According to the classification criteria for skin sensitisation, 4-chlororesorcinol is likely to be considered as a strong skin sensitiser, as the EC3-value is found to be less than 10%.


Migrated from Short description of key information:
4-chlororesorcinol is found to be sensitising to skin.

Justification for selection of skin sensitisation endpoint:
4-chlororesorcinol is considered as a strong skin sensitiser, as the EC3-value is found to be less than 10%, when tested as per Mouse local lymphnode assay (LLNA).

Respiratory sensitisation

Endpoint conclusion
Endpoint conclusion:
no study available

Justification for classification or non-classification

The available study indicates that the substance 4-Chlororesorcinol is likely to be classified as a skin sensitiser.