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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:
17/08/2016-23/08/2016
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2016
Report date:
2016

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to guideline
Guideline:
OECD Guideline 429 (Skin Sensitisation: Local Lymph Node Assay)
Qualifier:
according to guideline
Guideline:
EU Method B.42 (Skin Sensitisation: Local Lymph Node Assay)
GLP compliance:
yes (incl. QA statement)
Type of study:
mouse local lymph node assay (LLNA)

Test material

Constituent 1
Chemical structure
Reference substance name:
9β,11β-epoxy-17,21-dihydroxy-16β-methylpregna-1,4-diene-3,20-dione
EC Number:
213-563-4
EC Name:
9β,11β-epoxy-17,21-dihydroxy-16β-methylpregna-1,4-diene-3,20-dione
Cas Number:
981-34-0
Molecular formula:
C22H28O5
IUPAC Name:
17,21-dihydroxy-16-methyl-9,11-epoxypregna-1,4-diene-3,20-dione
Test material form:
solid: particulate/powder

In vivo test system

Test animals

Species:
mouse
Strain:
CBA/Ca
Sex:
female
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: TOXI-COOP ZRT. H-1103, Budapest, Cserkesz u.90
- Females (if applicable) nulliparous and non-pregnant: yes
- Microbiological status of animals, when known:
- Age at study initiation: young adult mice, 11-12 weeks old
- Weight at study initiation: 19.3-21.8 g
- Housing: grouped caging in small groups during acclimatization period; grouped caging (4 animals/ cage) during the test
- Diet (e.g. ad libitum): ad libitum
- Water (e.g. ad libitum): ad libitum
- Acclimation period: 14 days
- Indication of any skin lesions: no

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22 +/- 3°C
- Humidity (%): 30-70 %

Study design: in vivo (LLNA)

Vehicle:
dimethyl sulphoxide
Concentration:
maximum concentration 5%
No. of animals per dose:
4
Details on study design:
PRE-SCREEN TESTS:
- Irritation: No sign of significant irritation was observed.
- Systemic toxicity: No significant, treatment related effect on body weights or any other sign of systemic toxicity were observed in any treatment group.
- No sign of significant irritation (indicated by an erythema score ≥ 3 and/or an increase of ≥ 25 % of ear thickness observed on any day of measurement) or any other local effect was observed.


MAIN STUDY

ANIMAL ASSIGNMENT AND TREATMENT
- Name of test method:
- Criteria used to consider a positive response:

TREATMENT PREPARATION AND ADMINISTRATION:
Each mouse was topically treated with 25 μL of the appropriate formulations of the test item, the positive control substance or the vehicles using a pipette, on the dorsal surface of each ear. After the treatments animals were returned to their cages. Each animal was dosed once a day for three consecutive days (Days 1, 2 and 3). There was no treatment on Days 4, 5 and 6.
Positive control substance(s):
hexyl cinnamic aldehyde (CAS No 101-86-0)

Results and discussion

Positive control results:
The positive control group animals were treated with 25% (w/v) HCA solution (formulated in AOO) concurrent to the test item groups. No mortality, cutaneous reactions or signs of toxicity were observed in the positive control group.

In vivo (LLNA)

Results
Parameter:
SI
Value:
>= 3
Cellular proliferation data / Observations:
Since no failed treatment, obvious sign of systemic toxicity or irritation was observed during the test no treatment group was excluded from the evaluation.
No significant lymphoproliferative response (SI ≥ 3) compared to the relevant vehicle control (DMSO) was noted for beta methyl-epoxy at the tested concentrations. The observed stimulation index values were 0.7, 0.4, 0.8 and 0.8 at test item concentrations of 5 %, 2.5 %, 1 % and 0.5 % (w/v), respectively.
Significance of the dose-response was evaluated by linear regression using the SI values. No significant dose-response was observed (p = 0.67, r = 0.33).

Applicant's summary and conclusion

Interpretation of results:
GHS criteria not met
Conclusions:
Under the conditions of the present assay, beta methyl-epoxy tested at the maximum feasible concentration of 5 % (w/v, based on solubility) and also at concentrations of 2.5 %, 1 % or 0.5% (w/v) as formulations (apparently solutions) in a suitable vehicle (DMSO) was shown to have no skin sensitization potential in the Local Lymph Node Assay.