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Administrative data

Endpoint:
skin sensitisation: in vivo (non-LLNA)
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: GLP compliant guideline study, available as unpublished report, no restrictions, fully adequate for assessment

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1998
Report date:
1998

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to guideline
Guideline:
EU Method B.6 (Skin Sensitisation)
Qualifier:
according to guideline
Guideline:
OECD Guideline 406 (Skin Sensitisation)
GLP compliance:
yes
Type of study:
guinea pig maximisation test

Test material

Constituent 1
Chemical structure
Reference substance name:
2,5-dimethylhexyne-2,5-diol
EC Number:
205-533-4
EC Name:
2,5-dimethylhexyne-2,5-diol
Cas Number:
142-30-3
Molecular formula:
C8H14O2
IUPAC Name:
2,5-dimethylhex-3-yne-2,5-diol
Details on test material:
- Name of test material (as cited in study report): 2,5-Dimethyl-3-hexin-2,5-diol
- Physical state: solid, white
- Storage: room temperature

In vivo test system

Test animals

Species:
guinea pig
Strain:
Pirbright-Hartley
Sex:
female
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: Charles River GmbH, Wiga, Kisslegg, FRG
- Age at study initiation: young adults
- Weight at study initiation: 285 - 398 g
- Housing: 5 animals per cage, Makrolon type IV cages, with Granulat Type 3/4 (dust-free) SSNIFF bedding
- Diet: ad libitum, Kliba Labordiät 341 (Kaninchen-Meerschweinschen-Haltungsdiät) from Firma Klingentalmühle AG, Kaiseraugst, Switzerland
- Water: ad libitum, tap water 2 g ascorbic acid per 10 L water was added to the drinking water twice a week
- Acclimation period: 7 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 20 -24
- Humidity (%): 30 -70
- Air: fully air conditioned
- Photoperiod (hrs dark / hrs light): 12/12

Study design: in vivo (non-LLNA)

Inductionopen allclose all
Route:
intradermal and epicutaneous
Vehicle:
water
Concentration / amount:
- Intradermal induction: 5% in solution
- Epicutaneous induction: 50% in aqua bidest.
- challenge: 25% in aqua bidest.
Challengeopen allclose all
Route:
epicutaneous, occlusive
Vehicle:
water
Concentration / amount:
- Intradermal induction: 5% in solution
- Epicutaneous induction: 50% in aqua bidest.
- challenge: 25% in aqua bidest.
No. of animals per dose:
- Test material: 20
- Control: 10
Details on study design:
RANGE FINDING TESTS:
- Amount applied: 2 x 2 cm filter paper strips were applied to the skin of the flanks under an occlusive dressing (the bandage consists of rubberized linenpatches 4 x 4 cm from Russka and Fixomull®& Stretch (adhesive fleece) from Beiersdorf AG). The test filter paper strip was soaked in the test substance formulation.
- Exposure period: 2 times for 24 hours within a period of 96 hours in order to detect non-specific phenomena that are not caused by a sensitization reaction but could possibly be attributed to a shift in the irritation threshold.
- Site of application: flank, on the same area respectively
- Number of test animals: 4 per test concentration
- Readings: 24 and 48 h after the beginning of application

MAIN STUDY
A. INDUCTION EXPOSURE
- No. of exposures: 2 (day 0 intradermal injections + day 7 epicutaneous exposure)
- Intradermal induction: A row of six intradermal injections in groups of two per animal was made. These injections were: A) front row: 2 injections each of 0.1 mL Freund's adjuvant without test substance emulsified with 0.9% aqueous NaCl-solution in a ratio of 1:1, B) middle row: 2 injections each of 0.1 mL of the test substance formulation, C) back row: 2 injections each of 0.1 mL Freund's adjuvant/ 0.9% aqueous NaCl-solution (1 : 1) with test substance.
- Epicutaneous exposure: 2 x 4 cm filter paper strips were applied to the skin of the shoulder under an occlusive dressing (the bandage consists of rubberized linenpatches 6 x 4 cm from Russka and Fixomull® Stretch (adhesive fleece) from Beiersdorf AG). The filter paper strip was soaked in the test substance formulation.
- Exposure period (epicutaneous): 48 hours
- Site: shoulder
- Evaluation: 24 h after intradermal injections, and 48 h after epicutaneous exposure.

B. CHALLENGE EXPOSURE
- No. of exposures: 1
- Exposure: 2 x 2 cm filter paper strips were applied to the skin of the flank under an occlusive dressing (the bandage consists of rubberized linenpatches 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). The test filter paper strip was soaked in the test substance formulation.
- Day(s) of challenge: 14 days after the percutaneous induction
- Exposure period: 24 h
- Site: intact flank
- Evaluation (hr after challenge): 24 and 48
Challenge controls:
Identical procedure. A row of six intradermal injections in groups of two per animal A) front row: 2 injections each of 0.1 ml Freund's adjuvant without test substance emulsified with 0.9% aqueous NaCl-solution in a ratio of 1:1, B) middle row: 2 injections each of 0.1 ml of the vehicle, C) back row: 2 injections each of 0.1 ml Freund's adjuvant/ 0.9% aqueous NaCl-solution (1 : 1) with vehicle. Epicutaneous exposure not performed, since the distilled water used as formulating agent was not expected influence the result of the study.
Positive control substance(s):
yes
Remarks:
Alpha-Hexylcinnamaldehyde

Results and discussion

Positive control results:
In a positive control test with Alpha-Hexylcinnamaldehyde, performed two years before this study, in 85% of the animals sensitisation was observed.

In vivo (non-LLNA)

Resultsopen allclose all
Reading:
1st reading
Hours after challenge:
24
Group:
negative control
Dose level:
25%
No. with + reactions:
0
Total no. in group:
9
Remarks on result:
other: Reading: 1st reading. . Hours after challenge: 24.0. Group: negative control. Dose level: 25%. No with. + reactions: 0.0. Total no. in groups: 9.0.
Reading:
1st reading
Hours after challenge:
24
Group:
test chemical
Dose level:
25%
No. with + reactions:
0
Total no. in group:
16
Remarks on result:
other: Reading: 1st reading. . Hours after challenge: 24.0. Group: test group. Dose level: 25%. No with. + reactions: 0.0. Total no. in groups: 16.0.
Reading:
2nd reading
Hours after challenge:
48
Group:
negative control
Dose level:
25%
No. with + reactions:
0
Total no. in group:
9
Remarks on result:
other: Reading: 2nd reading. . Hours after challenge: 48.0. Group: negative control. Dose level: 25%. No with. + reactions: 0.0. Total no. in groups: 9.0.
Reading:
2nd reading
Hours after challenge:
48
Group:
test chemical
Dose level:
25%
No. with + reactions:
0
Total no. in group:
16
Remarks on result:
other: Reading: 2nd reading. . Hours after challenge: 48.0. Group: test group. Dose level: 25%. No with. + reactions: 0.0. Total no. in groups: 16.0.

Any other information on results incl. tables

- Intradermal induction: After the intradermal induction well-defined erythema and slight oedema were observed at the injection sites of all control group animals and all test group animals, at which only Freund's adjuvant / 0.9% aqueous NaCl-solution (1 :1) was applied. Injections of 5% test substance preparations in 0.9% aqueous NaCl-solution or in Freund's adjuvant / 0.9% aqueous NaCl-solution (1 :1) caused well-defined erythema and slight oedema in all test group animals. The injection sites of all control group animals, at which 0.9% aqueous NaCl-solution was applied, did not show any skin reactions.

 

- Percutaneous induction: After the percutaneous induction with a 50% test substance preparation incrustation, partially open (caused by the intradermal induction) could be observed in addition to well-defined erythema and slight oedema in all test group animals.

 

- Body weights: The expected body weight gain was generally observed in the course of the study.

- Mortality: 1 animal of control group 1 and 4 animals of the test group died 13, 17, 20 or 21 days after the beginning of the study. Macroscopic examination revealed that the animals suffered from pneumonia. The cause of death was not related to the test substance treatment.

Applicant's summary and conclusion

Interpretation of results:
not sensitising
Remarks:
Migrated information