3,7-dimethyloct-6-enyl isobutyrate

Skin sensitisation

Administrative data

Endpoint:

skin sensitisation: in vivo (non-LLNA)

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

data from handbook or collection of data

Justification for type of information:

data is from peer reviewed journals

Data source

Reference

Reference Type:

publication

Title:

The Freund's Complete Adjuvant Test and the Open Epicutaneous Test

Author:

G. Klecak

Year:

1985

Bibliographic source:

Curr. Probl. Derm., vol.14, pp.152-171 (Karger, Basel 1985)

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

other: as mentuined below

Principles of method if other than guideline:

An Open Epicutaneous Test (OET) was performed on guinea pigs to assess the skin sensitization potential of test chemical

GLP compliance:

not specified

Type of study:

not specified

Justification for non-LLNA method:

not specified

Test material

Test material information

Constituent 1

Reference substance name:

Reference substance 001

Cas Number:

97-89-2

Molecular formula:

C14H26O2

Details on test material:

- Name of test material:3,7-dimethyloct-6-en-1-yl 2-methylpropanoate
- Common Name: Citronellyl isobutyrate
- Molecular formula: C14H26O2
- Molecular weight : 226.3574 g/mol
- Smiles notation :C(OCC[C@@H](CC\C=C(\C)C)C)(C(C)C)=O
- InChl:1S/C14H26O2/c1-11(2)7-6-8-13(5)9-10-16-14(15)12(3)4/h7,12-13H,6,8-10H2,1-5H3
- Substance type: Organic
- Physical state: Liquid

In vivo test system

Test animals

Species:

guinea pig

Strain:

not specified

Sex:

male/female

Details on test animals and environmental conditions:

- Weight at study initiation: 300-450g

Study design: in vivo (non-LLNA)

Induction

Route:

epicutaneous, open

Vehicle:

other: ethanol, acetone, H20, petroleum, PEG and/or other suitable vehicles

Concentration / amount:

Concentration:4%
Amount: 0.1ml

Day(s)/duration:

3 weeks (0-21 days)

Adequacy of induction:

not specified

Challenge

No.:

#1

Route:

epicutaneous, open

Vehicle:

other: ethanol, acetone, H20, petroleum, PEG and/or other suitable vehicles

Concentration / amount:

4% - 0.025 ml

Day(s)/duration:

72 hours

Adequacy of challenge:

not specified

No. of animals per dose:

6–8 male and female guinea pigs

Details on study design:

RANGE FINDING TESTS: The Pretest was performed to establish the primary irritating threshold concentration of test substance. For this, a single application of 0.025 ml of each test concentration (e.g, 100, 30, 10 and 3%) is simultaneously performed on one of the areas measuring 2 cm2 of the flank skin previously clipped and marked with a circular stamp. Reactions are read 24 h after the application of the test material. On the basis of preliminary study, the maximal non-irritating concentration selected was 8%. Thus the sensitization test was conducted at a dose of 4% of test chemical.

MAIN STUDY
A. INDUCTION EXPOSURE
- No. of exposures: 21
- Exposure period:24 hours
- Test groups:6-8 guinea pigs
- Control group:3 guinea pigs
- Site: an area measuring 8 cm2 on the clipped flank skin of the guinea pigs
- Frequency of applications: The applications are repeated daily for 3 weeks or done 5 times weekly during 4 weeks
- Duration: 21 days (3 weeks)
- Concentrations: 4% in vehicle.
Amount: 0.1ml

B. CHALLENGE EXPOSURE
- No. of exposures: 2
- Day(s) of challenge: on days 21 and 35
- Exposure period:24 hours
- Test groups: 6-8 guinea pigs
- Control group: 3 guinea pigs
- Site: contralateral flank measuring 2 cm2
- Concentrations: Concentration:4%
Amount: 0.025ml
- Evaluation (hr after challenge): 24,48 and/or 72h.

Challenge controls:

The 10 controls were either left untreated or treated with 0.1 ml aliquot of the vehicle for 21 days

Positive control substance(s):

not specified

Results and discussion

In vivo (non-LLNA)

Results

Reading:

1st reading

Hours after challenge:

72

Group:

test chemical

Dose level:

4%

No. with + reactions:

0

Total no. in group:

6

Clinical observations:

no signs of dermal sensitization pbserved

Remarks on result:

no indication of skin sensitisation

Applicant's summary and conclusion

Conclusions:

The test chemical was considered to be not sensitizing on skin of guinea pigs at concentration of 4% in an Open Epicutaneous Test (OET).

Executive summary:

An Open Epicutaneous Test (OET) was performed on guinea pigs to assess the skin sensitization potential of test chemical.

 

The Pretest was performed to establish the primary irritating threshold concentration of test substance. For this, a single application of 0.025 ml of each test concentration (e.g, 100, 30, 10 and 3%) is simultaneously performed on one of the areas measuring 2 cm2 of the flank skin previously clipped and marked with a circular stamp. Reactions are read 24 h after the application of the test material. On the basis of preliminary study, the maximal non-irritating concentration selected was 4%. Thus the sensitization test was conducted at a dose of 4% of test chemical.

 

On day 1 during induction, 0.1 ml of test chemical was applied at concentrations of 4% in vehicle to an area measuring 8 cm2 on the clipped flank skin of the guinea pigs. The applications are repeated daily for 3 weeks or done 5 times weekly during 4 weeks, usually on the same skin sites. The application sites were left uncovered and the reactions, if continuous daily applications were performed, can be read 24 h after each application, or at the end of each week. 

To determine whether or not contact sensitization was induced, all groups of guinea pigs previously treated for 21 days, as well as 10 untreated, or only pretreated with the vehicle, controls are tested on days 21 and 35 on the contralateral flank with the test material. This test was performed by applying with a pipette 0.025 ml of each concentration to skin areas measuring 2 cm2. The reactions were read after 24, 48 and/or 72h.

 

It was observed that none of the guinea pigs induced contact sensitization at challenge concentration of 4%.Thus, the test chemical was considered to be not sensitizing on skin of guinea pigs at concentration of 4% in an Open Epicutaneous Test (OET).