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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:
May 03 - Jul 24, 2007
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2007
Report date:
2007

Materials and methods

Test guideline
Qualifier:
according to guideline
Guideline:
OECD Guideline 429 (Skin Sensitisation: Local Lymph Node Assay)
Deviations:
no
GLP compliance:
yes (incl. QA statement)
Type of study:
mouse local lymph node assay (LLNA)

Test material

Constituent 1
Chemical structure
Reference substance name:
1-ethoxy-2,3-difluoro-4-[(1s,4r)-4-propylcyclohexyl]benzene
EC Number:
605-718-3
Cas Number:
174350-05-1
Molecular formula:
C17H24F2O
IUPAC Name:
1-ethoxy-2,3-difluoro-4-[(1s,4r)-4-propylcyclohexyl]benzene
Test material form:
other: solid

In vivo test system

Test animals

Species:
mouse
Strain:
CBA
Sex:
female
Details on test animals and environmental conditions:
TEST ANIMALS- Source: Harlan Netherlands B.V. Postbus 6174 NL - 5960 AD Horst - Age at study initiation: 7 - 8 weeks - Weight at study initiation: 18,5 +/- 1,0- Housing: single- Diet (e.g. ad libitum): ad libitum - Water (e.g. ad libitum): ad libitum - Acclimation period: 7 daysENVIRONMENTAL CONDITIONS- Temperature (°C): 22 + 3°C- Humidity (%): 30-88%- Photoperiod (hrs dark / hrs light): 12/12IN-LIFE DATES: From: day 1 To: day 5

Study design: in vivo (LLNA)

Vehicle:
acetone/olive oil (4:1 v/v)
Concentration:
pre test for signs of irritation: 2.5, 5, 10 and 25 % (v/v)main test: 5, 10 and 25 % (v/v)
No. of animals per dose:
pre test: 2main test: 5 (f) per group (3 test groups, 1 control group) total 20 (f)
Details on study design:
RANGE FINDING TESTS:- Compound solubility: solubility in vehicle was demonstrated- Irritation: pre test performed- Lymph node proliferation response: no dataMAIN STUDYANIMAL ASSIGNMENT AND TREATMENT- Name of test method: OECD TG 429- Criteria used to consider a positive response: 3-fold greater response at one concentration in SI than control animals TREATMENT PREPARATION AND ADMINISTRATION:a) Topical application of 25 µL test item preparation (test group) or vehicle (control group)b) five days after topical application: iv application of 3H-methyl thymidin c) prior each treatment (a and b) ear thickness measurementd) five hours after treatment (b) necropsy and analysis of the 3H thymidin incorporation in draining lymph nodese) method: pooled per animal
Positive control substance(s):
hexyl cinnamic aldehyde (CAS No 101-86-0)
Statistics:
Dunnets Test

Results and discussion

Positive control results:
Conc. SI
5%: 2.43
10% 4.07
25% 4.88

In vivo (LLNA)

Resultsopen allclose all
Key result
Parameter:
SI
Value:
1.83
Test group / Remarks:
5% test item
Key result
Parameter:
SI
Value:
1.69
Test group / Remarks:
10% test item
Key result
Parameter:
SI
Value:
1.04
Test group / Remarks:
25% test item
Cellular proliferation data / Observations:
CELLULAR PROLIFERATION DATA

Control: 508.3 DPM/lymph node
5% test item: 930.0 DPM/lymph node
10% test item: 858.1 DPM/lymph node
25% test item: 530.4 DPM/lymph node

EC3 CALCULATION

The EC3 value could not be calculated since all SI's are below 3.

CLINICAL OBSERVATIONS:

No deaths occured. No symptoms of local toxicity at the ears of the animals and no systemic findings were observed.

BODY WEIGHTS

The body weight of the animals, recorded prior to the first application and prior to treatment with 3HTdR, was within the range commonly recorded for animals of this strain and age.

Applicant's summary and conclusion

Interpretation of results:
GHS criteria not met
Conclusions:
From the data it can be concluded that the test item is not a skin sensitiser under the conditions of this assay.
Executive summary:

Study Design

In the study the test item was dissolved in acetone:olive oil (4+1) was assessed for its possible contact allergenic potential.
For this purpose a local lymph node assay was performed using test item concentrations of 5, 10, and 25%. The GLP study was performed according to OECD TG 429.

Results

The animals did not show any clinical signs during the course of the study and no cases of mortality were observed.
A relevant increase in ear thickness gain could not be observed after treatment with the test item.
In this study Stimulation Indices (S.I.) of 1.83, 1.69, and 1.04 were determined with the test item at concentrations of 5, 10, and 25% in acetone:olive oil (4+1), respectively. Since the S.I. was not increased above 3 at any test group, no EC3 could be determined.

Conclusion

From the data it can be concluded that the test item is not a skin sensitiser under the conditions of this assay.