2-Propanol, 1,3-bis(2,6-dimethylphenoxy)-

Skin sensitisation

Administrative data

Endpoint:

skin sensitisation: in vivo (LLNA)

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2008-05-23 to 2008-09-15

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP and guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2008

Report date:

2008

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 429 (Skin Sensitisation: Local Lymph Node Assay)

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

EPA OPPTS 870.2600 (Skin Sensitisation)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Type of study:

mouse local lymph node assay (LLNA)

Test material

Test material information

Constituent 1

Reference substance name:

1,3-bis(2,6-dimethylphenoxy)propan-2-ol

EC Number:

617-745-8

Cas Number:

856976-65-3

Molecular formula:

C19 H24 O3

IUPAC Name:

1,3-bis(2,6-dimethylphenoxy)propan-2-ol

In vivo test system

Test animals

Species:

mouse

Strain:

CBA

Sex:

female

Details on test animals and environmental conditions:

Age on day 0: 6 – 12 weeks
Body weight on day 0: 19.2 g – 22.5 g
Acclimatization period 7 days before the first test-substance application.
The single housed animals were identified by cage cards.
The animals were housed in fully air-conditioned rooms. Central air-conditioning guaranteed a range of 20 – 24°C for temperature and of 30 – 70% for relative humidity. The day/night rhythm was 12 h light and 12 h darkness.
Single housing in Makrolon cages, type II.
Bedding: Lignocel FS14; SSNIFF
Feeding: Kliba-Labordiaet (Maus / Ratte Haltung “GLP”), Provimi Kliba SA, Kaiseraugst, Basel, Switzerland, ad libitum
Drinking water: Tap water ad libitum

Study design: in vivo (LLNA)

Vehicle:

methyl ethyl ketone

Concentration:

3%, 10% and 50% w/w preparations in MEK, in control group only MEK
Each test animal was applied with 25 μL per ear of the respective test-substance preparation to the dorsum of both ears for three consecutive days. The control group was treated with 25 μL per ear of the vehicle alone.

No. of animals per dose:

5

Details on study design:

Form of application: Epicutaneous application is simulating dermal contact with the compound which is possible to occur under practical use conditions.
Frequency of application: 3 consecutive applications (day 0 – day 2) to the same application site
The test-substance preparation was produced on a weight per weight basis shortly before the application. After stirring with a magnetic stirrer the test substance was soluble in the vehicle.

TREATMENT PREPARATION AND ADMINISTRATION: Prior to first application, the animals were distributed to the individual groups, received their animal numbers and were allocated to the respective cages according to the randomization instructions of „Nijenhuis, A. and Wilf, H.S.: Combinatorial Algorithms, Academic Press, New York, San Francisco, London, 1978, pp. 62 – 64“

On study day five (about 66 to 72 hours after the last application of test substance to the ears) the mice were injected intravenously with 20 μCi of 3H-thymidine in 250 μl of sterile saline into a tail vein. The animals were sacrificed on study day 5 about 5 hours after 3H-thymidine injection by cervical dislocation. The ear weight was determined, the weight of the lymph nodes, cell count were determined and the 3H thymidine incorporation of the lymph node cells was measured.

Positive control substance(s):

hexyl cinnamic aldehyde (CAS No 101-86-0)

Statistics:

Table(s) and/or figure(s) of measured parameters presented in the report were produced using PC based tabular calculation software. The mean and individual data were not always rounded but the significant digits were produced by changing the display format. As a consequence, calculation of mean values using the individual data presented in the report will, in some instances, yield minor variations in value.

Results and discussion

In vivo (LLNA)

Results

Results 1

Parameter:

SI

Remarks on result:

other: see Remark

Remarks:

When considering the concurrent control values the 10% and 50% preparations of the test substance in MEK induced a biologically relevant response (increase to 1.5fold or above of control value = simulation index (SI) 1.5) in the auricular lymph node cell counts. Because the cell count of the concurrent control group was at the lower end of the historical control data, the stimulation indices were additionally calculated in relation to the mean historical control value. This leads to the reduction of stimulation indices below or to the border of a biologically relevant response. The cell count SIs calculated with the historical control correspond to finding that the increase of 3H-thymidine incorporation into the cells was not biologically relevant (increase above the cut off stimulation index of 3) at all concentrations. Additionally, the 3H-thymidine incorporation did not show a concentration response relation. Some increase in lymph node weights occurred after treatment with all test substance preparations. In addition, minimal increase in ear weights was observed in mice treated with all test substance preparations without concentration relation, as indication of some ear irritation. Minimal white residues of test substance were noted in all animals of test group 4 on study days 1 and 2. Based on the results described above, it is concluded that the lymph node response observed on the presence of some skin irritation cannot be interpreted as indication for skin sensitization. Thus the test item does not show a skin sensitizing effect in the Murine Local Lymph Node Assay under the test conditions chosen. Results Stimulation Index: (3H-thymidine incorporation) Vehicle MEK: 1.00 3% in MEK: 2.29 10% in MEK: 1.92 50% in MEK: 2.26

Results 2

Parameter:

other: disintegrations per minute (DPM)

Remarks on result:

other: DPM/Lymph Node Pair (3H-thymidine incorporation) Vehicle MEK: 305.7 3 % in MEK: 699.7 10 % in MEK: 588.2 50 % in MEK: 691.9