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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.

The new ECHA CHEM database has been released by ECHA, and it now contains all REACH registration data. There are more details on the transition of ECHA's published data to ECHA CHEM here.

Diss Factsheets

Toxicological information

Skin sensitisation

Currently viewing:

Administrative data

Endpoint:
skin sensitisation: in vivo (LLNA)
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2004
Report date:
2004

Materials and methods

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

Test material

Constituent 1
Chemical structure
Reference substance name:
2-butyloctanoic acid
EC Number:
248-570-1
EC Name:
2-butyloctanoic acid
Cas Number:
27610-92-0
Molecular formula:
C12H24O2
IUPAC Name:
2-butyloctanoic acid
Test material form:
liquid
Details on test material:
- Name of test material: 2-butyl octanoic acid
- Molecular formula: C12H24O2
- Molecular weight: 200.32 g/mole
- Smiles notation: O=C(O)C(CCCCCC)CCCC

In vivo test system

Test animals

Species:
mouse
Strain:
other: CBA/Ca
Sex:
female
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: Charles River UK Limited, Kent, England
- Age at study initiation: 7-8 weeks
- Weight at study initiation: 16-19 g
- Housing: in pairs in suspended cages (dimensions 36.5 x 20.7 x 14 cm) with stainless steel grid tops and solid bottoms, bedding: wood shavings and nesting material (Nestlets, supplied by Datesand Limited Manchester, UK)
- Diet: Rat and Mouse No. 1 Maintenance Diet ad libitum, supplied by Special Diets Services Limited, Essex, UK
- Water: Water from the domestic mains supply ad libitum
- Acclimation period: 8 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 21-22
- Humidity (%): 55 (mean)
- Air changes (per hr): 15
- Photoperiod (hrs dark / hrs light): 12/12

IN-LIFE DATES: From: 2003-06-25 To: 2003-07-02

Study design: in vivo (LLNA)

Vehicle:
acetone/olive oil (4:1 v/v)
Concentration:
10, 25 and 50%
No. of animals per dose:
4
Details on study design:
RANGE FINDING TESTS:
not performed, dose levels were selected based on existing data from a test on the test substance, produced under an old production process

MAIN STUDY
ANIMAL ASSIGNMENT AND TREATMENT
- Name of test method: (3H)-methyl thymidine
- Criteria used to consider a positive response: stimulation index (SI) >=3, together with consideration of dose-response and, where appropriate, statistical significance

TREATMENT PREPARATION AND ADMINISTRATION:
For 3 consecutive days, animals received open application of 25 µl of the appropriate formulation onto the dorsum of each ear. There were no treatment on Days 4 and 5. On Day 6 each animal received an intravenous injection of 250 µl of phosphate buffered saline (PBS) containing 20 µCi of 3H-methyl thymidine into the lateral tail vein. Approx. 5 h after intravenous administration animals were killed by exposure to carbon dioxide and exsanguinated. Each pair of draining auricular lymph nodes was collected from each animal. A single cell suspension of lymph node cells from each group was prepared by gentle mechanical desegregation through 200 µm mesh stainless steel gauze. The lymph node cells were washed twice in an excess of PBS and precipitated with 5% trichloroacetic acid at approx. 4°C for 18 h. The pellets were resuspended and solubilised in 200 µl soluene. Scintillation fluid (10 ml) was added and incorporation of tritiated thymidine measured by ß-scintillation counting as disintegrations per minute (dpm).
Positive control substance(s):
hexyl cinnamic aldehyde (CAS No 101-86-0)
Statistics:
no statitistics performed

Results and discussion

Positive control results:
The methods used on this study were periodically checked in the testing facility. Stimulation indices in recent positive control studies were 2.3, 5.5 and 7.5 in March 2003 and 1.9, 4.3 and 11.7 in May 2003 at concentrations of 10, 20 and 40% hexyl cinnamic aldehyde, thereby indicating that the test method employed is valid.

In vivo (LLNA)

Resultsopen allclose all
Key result
Parameter:
SI
Value:
1
Test group / Remarks:
10 % (new batch)
Key result
Parameter:
SI
Value:
2.6
Test group / Remarks:
25 % (new batch)
Key result
Parameter:
SI
Value:
1.7
Test group / Remarks:
50 % (new batch)
Key result
Parameter:
SI
Value:
1.9
Test group / Remarks:
50 % (old batch)

Any other information on results incl. tables

No adverse clinical signs were noted at any dose level in this study.

Body weight gain for animals receiving test substance was similar to controls.

Applicant's summary and conclusion

Interpretation of results:
GHS criteria not met
Conclusions:
The target substance and Category Member 2 was considered not to be a sensitiser in mice.
Executive summary:

Delayed contact hypersensitivity potential of the target substance was investigated using CBA/Ca mice. The study was performed according to OECD guideline 429 and OECD Principles of Good Laboratory Practice.

Three groups of 4 female mice received an open application of 25µl of test substance onto the dorsum of each ear at concentrations of 10%, 25% or 50%. Another group of 4 females received only the vehicle, acetone:olive oil (4:1, v/v). Treatment was for 3 consecutive days. Three days later each animal received an intravenous injection of 3H-methyl thymidine, and 5 h later the draining lymph nodes were collected and the incorporation of tritiated thymidine assessed by scintillation counting.

On comparing the groups treated with the test substance with the control group, the Stimulation Indices were calculated to be 1.0, 2.6 and 1.7 for 10%, 25% and 50%, respectively.

Under the conditions of the study, the test substance was considered not to be a sensitiser in mice.