Isotridecan-1-ol

Skin sensitisation

Administrative data

Endpoint:

skin sensitisation: in vivo (non-LLNA)

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Justification for type of information:

see justification attached to chapter 13

Cross-reference

Cross-reference 1

Reason / purpose for cross-reference:

read-across source

Reference

Endpoint:

skin sensitisation: in vivo (non-LLNA)

Type of information:

experimental study

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

comparable to guideline study with acceptable restrictions

Principles of method if other than guideline:

Modified Draize procedure:
Hartley strain albino guinea pigs were treated by intradermal injection to induce sensitization and challenged 2 weeks later by both intradermal injection and topical application. When there was no evidence of sensitization the induction and challenge procedures were repeated.

GLP compliance:

no

Type of study:

other: modified Draize test

Justification for non-LLNA method:

Test performed before LLNA guideline was available.

Species:

guinea pig

Strain:

Hartley

Sex:

male/female

Details on test animals and environmental conditions:

TEST ANIMALS
- Source: from own colony (Unilever Research Laboratory, Great Britain)
- Weight at study initiation: about 350 g
- Housing: in pairs of the same sex
- Diet: pelleted guinea pig diet, cabbage, and hay; ad libitum
- Water: ad libitum

Route:

intradermal

Vehicle:

not specified

Concentration / amount:

2.5x the ICC = 0.25%

Route:

intradermal and epicutaneous

Vehicle:

not specified

Concentration / amount:

- injection challenge concentration (ICC): 0.1%;
- application challenge concentration (ACC): 10%

No. of animals per dose:

4 males, 6 females (or visa versa)

Details on study design:

RANGE FINDING TESTS:

Preliminary irritation test:
- Intradermal injection: Four animals of the same sex and weighing about 450 g were each injected intradermally on the shaved flanks with 0.1 ml aliquots of a range of concentrations of tests material in a suitable solvent. The reactions were examined for size (two largest diameters), erythema and edema 24 h later and the concentration giving slight but perceptible irritation with no edema was selected as the injection challenge concentration (ICC).
- Topical application: Aliquots (0.1 ml) of a range of concentrations of test substance in a suitable solvent were applied in small circular areas to the shaved flanks of 4 guinea pigs of the same sex and weighing about 450 g. The reactions were examined for erythema 24 h later and the highest concentration which caused no irritation was selected as the application challenge concentration (ACC).

MAIN STUDY:

10 guinea pigs were injected intradermally aliquots of 2.5 times the ICC at 4 sites which overlie the 2 auxillary and 2 inguinal lymph nodes. 14 days later each animal was challenged intradermally in one flank and topical in the other with 0.1 ml test substance preparation. The topical application was done by spreading 0.1 ml onto the shaven flank in a small circular area, which was not covered. 24 hours later the reactions were scored and apparent sensitization reactions were confirmed 7 days later by a second challenge with controls included. In the absence of sensitization reactions at first challenge the induction and challenge procedures were repeated, but this time a comfirmatory challenge with controls was included irrespective of any apparent sensitization reactions at the previous challenge.
Reactions were examined under a Philips color-matched unit with 3 Philips 40 W actinic blue 05 fluorescent tubes and 3 Philips 40 W white 35 fluorescent tubes. Each injection reaction was given a total score based on size (2 largest diameters), erythema and edema. Individual reactions were considered positive when their total score was significantly greater than the average total score for control reactions. Application reactions were scored on a 0 to +++ scale and individual reactions were considered positive if (a) they were + or greater and (b) there were no erythema reactions in controls.

Challenge controls:

At each challenge with controls, 4 previously untreated animals of the same sex and weight were treated intradermally and topically on opposite flanks with 0.1 ml aliquots at the ICC and ACC respectively.

Positive control substance(s):

not specified

Remarks on result:

no indication of skin sensitisation

Interpretation of results:

GHS criteria not met

Cross-reference 2

Reason / purpose for cross-reference:

read-across source

Reference

Endpoint:

skin sensitisation: in vivo (non-LLNA)

Type of information:

experimental study

Adequacy of study:

weight of evidence

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 406 (Skin Sensitisation)

Qualifier:

according to guideline

Guideline:

EU Method B.6 (Skin Sensitisation)

Qualifier:

according to guideline

Guideline:

EPA OPPTS 870.2600 (Skin Sensitisation)

GLP compliance:

yes (incl. QA statement)

Type of study:

Buehler test

Justification for non-LLNA method:

Test performed before LLNA guideline was available.

Species:

guinea pig

Strain:

Dunkin-Hartley

Sex:

female

Details on test animals and environmental conditions:

- Test species / strain / quality: Guinea pigs / Dunkin Hartley, Crl:HA
- Reasons for the selection of the test species: The guinea pig has been the animal of choice for predictive sensitization tests for several decades.
- Age on day 0: 5 – 9 weeks
- Sex: Female
- Supplier: Charles River Laboratories, Research Models and Services, Germany GmbH, Stolzenseeweg 32 – 36, 88353 Kisslegg
- Arrival in the testing facility: Acclimatization period (21 days before the first test-substance application)
- Identification: Ear tattoo
- Body weight on day 0: 401 g – 461 g

HOUSING CONDITIONS
- Room temperature / relative humidity: 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. There were no deviations from these ranges, which influenced the results of the study.
- Day / night rhythm: 12 h / 12 h (6.00 a.m. – 6.00 p.m. / 6.00 p.m. – 6.00 a.m.)
- Type of cage: Plastic cages from Tecniplast Deutschland GmbH (type 3020W009) with perforated base; floor area: 4000 cm²
- Enrichment: Wooden gnawing blocks (Typ NGM E-022); Abedd ® Lab. and Vet. Service GmbH Vienna, Austria
- Number of animals per cage: 5
- Feeding: Kliba Labordiät (Kaninchen & Meerschweinchenhaltung "GLP"), Provimi Kliba SA, Kaiseraugst, Basel, Switzerland ad libitum
- Drinking water: Tap water ad libitum

Route:

epicutaneous, occlusive

Vehicle:

unchanged (no vehicle)

Concentration / amount:

undiluted

Route:

epicutaneous, occlusive

Vehicle:

unchanged (no vehicle)

Concentration / amount:

undiluted

No. of animals per dose:

Groups Number of animals
Control group 1 10
Control group 2 10
Test group 20

Details on study design:

RANGE FINDING TESTS
In accordance with the cited Guidelines a slightly irritating concentration should be used in the main test for induction whereas the maximum non-irritant concentration should be applied for challenge.
- Amount applied: 0.5 mL of the test substance / test-substance preparation was applied to each animal.
- Occlusive dressing: 2 x 2 cm gauze patches (6 layers surgical gauze Ph. Eur. from Lohmann GmbH & Co. KG) containing the test substance / test-substance preparation were applied to the skin of the flanks under an occlusive dressing. The dressing consisted of rubberized linen patches (4 x 4 cm from Russka), patches of Idealbinde (5 x 5 cm from Pfälzische Verbandstoff-Fabrik) and Fixomull® Stretch (adhesive fleece) from Beiersdorf AG.
- Duration of exposure: 6 hours
- Application site: Right and left flank
- Application frequency: One application
-Number of test animals: 2 per test-substance concentration
-Readings: 1, 24 and 48 h after removal of the patch

MAIN STUDY
- Body weight determination: Individual body weights on day 0 and on the last day of observation (with the exception of the 2nd control group).
- Mortality: Twice each workday (beginning and end) and once on Saturdays, Sundays and on public holidays.

A. INDUCTION EXPOSURE
3 inductions were conducted.
- Amount applied: 0.5 mL of the test substance was applied to each animal.
- Occlusive dressing: 2 x 2 cm gauze patches (6 layers surgical gauze Ph. Eur. from Lohmann GmbH & Co. KG) containing the test substance were applied to the skin of the flank under an occlusive dressing. The dressing consisted of rubberized linen patches (4 x 4 cm from Russka), patches of Idealbinde (5 x 5 cm from Pfälzische Verbandstoff-Fabrik) and Fixomull® Stretch (adhesive fleece) from Beiersdorf AG.
- Duration of exposure: 6 hours
- Application site: Intact flank
- Application frequency: Three times at weekly intervals; days 0, 7 and 14 on the same application site
- Readings: 24 h after the removal of the patch
The control groups were not treated, since the test substance was applied undiluted and thus no vehicle was used.


B. CHALLENGE EXPOSURE
The challenge was carried out 14 days after the third induction.
- Amount applied: 0.5 mL of the test substance was applied to each animal. Occlusive dressing: 2 x 2 cm gauze patches (6 layers surgical gauze Ph. Eur. from Lohmann GmbH & Co. KG) containing the test substance were applied to the skin of the flank under an occlusive dressing. The dressing consisted of rubberized linen patches (4 x 4 cm from Russka), patches of Idealbinde (5 x 5 cm from Pfälzische Verbandstoff-Fabrik) and Fixomull® Stretch (adhesive fleece) from Beiersdorf AG.
- Duration of exposure: 6 hours
- Application site: Intact flank
- Readings: 24 and 48 h after the removal of the patch
The test group and control group 1 were treated with the test substance (control group 2 remained untreated).

Positive control substance(s):

not required

Remarks:

However, a separate study is performed twice a year in the laboratory. The positive controls with Alpha-Hexylcinnamaldehyde, techn. 85% showed that the test system was able to detect sensitizing compounds under the laboratory conditions chosen.

Group:

test chemical

No. with + reactions:

0

Total no. in group:

20

Remarks on result:

other: Group: test group. No with. + reactions: 0.0. Total no. in groups: 20.0.

CLINICAL OBSERVATIONS AND ASSESSMENT OF FINDINGS

Pretest for selection of epidermal induction and challenge concentration:

The undiluted test substance and a 50% test substance preparation in acetone were tested. After application of both concentrations no skin irritation could be observed.

MAIN STUDY

Induction:

The inductions with the undiluted test substance caused the following skin reactions:

Skin findings	Test group Inductions
	1st	2nd	3rd
Grade 0 Grade 1	20/20 -	20/20 -	15/20 5/20

x/y: number of animals with findings / number of animals tested (reading 24 h after removal of the

patch)

Challenge:

The challenge with the undiluted test substance did not cause any skin reactions neither in animals of the control group 1 nor in test group animals 24 and 48 hours after removal of the patch.

Control group 2 that had been intended for a potential rechallenge, was not treated and therefore not reported.

Body weights:

The expected body weight gain was generally observed in the course of the study.

Interpretation of results:

GHS criteria not met

Materials and methods

Test material

Test material information

Constituent 1

Reference substance name:

Isotridecan-1-ol

EC Number:

248-469-2

EC Name:

Isotridecan-1-ol

Cas Number:

27458-92-0

Molecular formula:

C13H28O

IUPAC Name:

2-methyldodecan-1-ol

Details on test material:

- Name of test material: Isotridecanol
- Smile code: OCCCCCCCCCCC(C)C

Results and discussion

In vivo (non-LLNA)

Results

Key result

Remarks on result:

no indication of skin sensitisation