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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.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

Administrative data

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
Study period:
2000-11-08 to 2000-11-14
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Qualifier:
equivalent or similar to guideline
Guideline:
OECD Guideline 429 (Skin Sensitisation: Local Lymph Node Assay)
Version / remarks:
(based on draft test guideline)
GLP compliance:
yes
Type of study:
mouse local lymph node assay (LLNA)
Specific details on test material used for the study:
- Name of test material (as cited in study report): 2-methylundecenal
- Substance type: Slightly viscous clear colourless liquid
- Physical state: Liquid
- Analytical purity: 95% (v/v)
- Impurities (identity and concentrations): No data
- Composition of test material, percentage of components: No data
- Isomers composition: No data
- Purity test date: No data
- Lot/batch No.: No data
- Expiration date of the lot/batch: No date but comment that "Stability was assured by reference to the expiry dates provided by the supplier"
- Stability under test conditions: No data
- Storage condition of test material: Ambient conditions under nitrogen
- Compound Control Sample No: S2352501
- Manufacturer: Sigma
Species:
mouse
Strain:
CBA
Sex:
female
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: Harlan UK Ltd
- Age at study initiation: 7-12 wks old
- Weight at study initiation: No data
- Housing: 4 per cage
- Diet: SDS RM1 (E) SQC pelleted diet ad libitum.
- Water: Tap water ad libitum.
- Acclimation period: No data

ENVIRONMENTAL CONDITIONS
- Temperature: 21 ± 3 °C
- Humidity: 50 % ± 20 %
- Air changes (per hr): No data
- Photoperiod: 12 hrs light/2 hrs dark/8 hrs off/2 hrs dimmed in each 24 hr period.
Vehicle:
acetone/olive oil (4:1 v/v)
Concentration:
0 (control), 0.5, 1.0, 2.5, 5.0 and 10.0 % (w/v).
No. of animals per dose:
4
Details on study design:
TOPICAL APPLICATION
- Each group of mice was treated by topical application with 25µL of the test or control substance to the dorsal surface of each ear for 3 consecutive days.

ADMINISTRATION OF ³HTdR
- 5 days after the first topical application, mice were administered with 20mCi ³HTdR in phosphate buffered saline (PBS) by intravenous tail vein injection with 250µL of 80µCi/mL ³HTdR (78.9µCi/µL ³HTdR following activity confirmation). The tail veins were visualised by placing the mice in a warm air environment for a few minutes.

DETERMINATION OF INCORPORATED ³HTdR
- Approx. 5 hr after ³HTdR injection all mice were sacrificed by CO₂ asphyxiation.
- The draining auricular lymph nodes were rapidly excised and pooled for each experimental group (8 nodes/group) into 1mL of phosphate buffered saline (PBS).
- Single cell suspensions (SCSs) of pooled lymph node cells (LNC) were prepared by gentle mechanical disaggregation of pooled lymph nodes through stainless steel gauze (200 mesh size) using a 5mL ‘B-D discardit’ syringe plunger in a petri dish.
- Approximately 8mL of PBS were subsequently used to wash the mesh and swill the petri dish before each group of pooled LNC SCS was recovered by aspiration, transferred into a centrifuge tube and made up to 10ml with PBS. Pooled LNC were pelleted by centrifugation at 190g (RCF) for 10 mins and the supernatants removed by aspiration before resuspending each LNC pellet with 10mL of PBS. This washing procedure was repeated twice before resuspending each LNC pellet in 3ml of 5% trichloroacetic acid (TCA) for precipitation of macromolecules.
- After incubation with 5 % TCA at 4°C overnight, each precipitate was pelleted and resuspended in 1mL of 5 % TCA. After transferring the precipitates to glass scintillation vials with 10mL of ‘Optiphase mp’ scintillation liquid ³HTdR incorporation was measured on a β-scintillation counter.
- Similarly, background ³HTdR levels were also measured in two 1mL aliquots of 5 % TCA.
- The β-scintillation counter expresses ³HTdR incorporation as the number of radioactive disintegrations per minute (DPM).

INTERPRETATION OF RAW DATA
- The proliferative responses of LNC were expressed as the number of radioactive disintegrations per minute per lymph node (DPM/node) and as the ratio of ³HTdR incorporation into LNC of test lymph nodes relative to that recorded for control lymph nodes (Stimulation Index- SI).
- Before DPM/node values were determined, mean background DPM was subtracted from test and control DPM raw data.

- A test substance was regarded as a sensitiser in the LLNA if the following criteria were fulfilled:
--1. that exposure to at least 1 concentration of the test substance resulted in an incorporation of ³HTdR at least 3-fold or greater than that recorded in the control mice, as indicated by the SI.
--2. that the data were not incompatible with a conventional biological dose response, although allowance would have been made (especially at high topical application concentrations) for either local toxicity or immunological suppression.
Key result
Parameter:
EC3
Value:
10
Parameter:
SI
Value:
1.4
Test group / Remarks:
concentration 0.5%
Parameter:
SI
Value:
1.3
Test group / Remarks:
concentration 1%
Parameter:
SI
Value:
1.3
Test group / Remarks:
concentration 2.5%
Parameter:
SI
Value:
2.4
Test group / Remarks:
concentration 5%
Parameter:
SI
Value:
3
Test group / Remarks:
concentration 10%

2-methylundecanal in AOO elicited a positive lymphocyte response (Stimulation Index (SI) ≥ 3) at 10.0 % which gave a SI of 3.0. The response was negative (SI < 3) at the other concentrations tested (0.5 %, 1.0 %, 2.5 % and 5.0 %). EC3 = 10. There was evidence of a dose response.

Background count - 66 DPM.  DPMs (less background count): 0 % - 3406 dpm, 0.5 % - 4794 dpm, 1.0 % - 4427 dpm, 2.5 % - 4572 dpm, 5.0 % - 8041 dpm, 10.0 % - 10090 dpm
Interpretation of results:
Category 1B (indication of skin sensitising potential) based on GHS criteria
Conclusions:
The test substance was assessed for skin sensitisation according to OECD guideline 429. The test material was found to be sensitising to skin at 10 % w/v.
Endpoint conclusion
Endpoint conclusion:
adverse effect observed (sensitising)
Additional information:
The test substance was assessed for skin sensitization using a murine local lymph node assay according to OECD guideline 429. The substance was found to be sensitising with a Stimulation Index value of 3.0 at a concentration of 10 % (w/v), but not at lower concentrations tested. Evidence of a dose-response relationship was also found.

Migrated from Short description of key information:
The test substance was assessed for skin sensitisation according to OECD guideline 429. The test material was found to be sensitising to skin at 10 % w/v.

Justification for selection of skin sensitisation endpoint:
The study was performed on the target substance according to OECD guideline 429.

Respiratory sensitisation

Endpoint conclusion
Endpoint conclusion:
no study available

Justification for classification or non-classification

The test substance was assessed for skin sensitisation according to OECD guideline 429. The test material was found to be sensitising to skin and should be classified for skin sensitisation.