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Toxicological information

Skin sensitisation

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Administrative data

Endpoint:
skin sensitisation: in vivo (non-LLNA)
Type of information:
experimental study
Adequacy of study:
key study
Study period:
1998-03-16 to 1998-04-16
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

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:
OECD Guideline 406 (Skin Sensitisation)
Version / remarks:
(1992)
Deviations:
no
Qualifier:
according to
Guideline:
EU Method B.6 (Skin Sensitisation)
Version / remarks:
(1996)
Deviations:
no
GLP compliance:
yes (incl. certificate)
Type of study:
Buehler test
Justification for non-LLNA method:
A skin sensitization test according to OECD 406 has already excisted since 1998 and is sufficient for evaluation of the skin sensitisation potential of the test substance.

Test material

Reference
Name:
Unnamed
Type:
Constituent
Test material form:
other: liquid
Details on test material:
2,2,4(or 2,4,4)-trimethyl-1,6-hexanediol of Hüls AG
purity 94.6 % (GC-FID area)
batch No. Pt. 15570/3033 of August 1995; sample ID 0637/81 770

In vivo test system

Test animals

Species:
guinea pig
Strain:
Dunkin-Hartley
Sex:
female
Details on test animals and environmental conditions:
TEST ANIMALS: 
- Strain: Dunkin-Hartley, Pirbright White, Hsd/Poc:DH (SPF)
- Sex: female
- Source: Harlan Winkelmann GmbH, Borchen (Germany)
- Age: healthy young adults
- Weight at study initiation: 326 g (mean test); 322 g (mean control)
- Housing: max 5 animals per cage
- Diet (e.g. ad libitum): Sniff G 4 diet, standard guinea pig diet, Ssniff Spezialfutter GmbH, 59494 Soest, Germany
- Water (e.g. ad libitum): tap water
- Acclimation period: at least 5 days
- Controls: 10 animals; treatment: vehicle

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22 +/- 3°C
- Humidity (%): 30 - 70 %
- Air changes (per hr):15 air changes/hour
- Photoperiod (hrs dark / hrs light): 12 hour light/dark rhythm

Study design: in vivo (non-LLNA)

Induction
Route:
epicutaneous, occlusive
Vehicle:
unchanged (no vehicle)
Concentration / amount:
6 hour occlusive patch (left side), 0.3 ml undiluted; then removal of  residual test material
Day(s)/duration:
day 0/7/14 for 6 hours
Adequacy of induction:
other: undilluted substance is non irritating
Challenge
No.:
#1
Route:
epicutaneous, occlusive
Vehicle:
unchanged (no vehicle)
Concentration / amount:
two 6 hour occlusive patches (right side), one with 0.3 ml test  substance and one with vehicle   subsequent removal of residual test material
Day(s)/duration:
day 28 for 6 hours
Adequacy of challenge:
highest non-irritant concentration
No. of animals per dose:
20
Details on study design:
1st application: Induction undiluted occlusive epicutaneous
2nd application: Induction undiluted occlusive epicutaneous
3rd application: Induction undiluted occlusive epicutaneous
ADMINISTRATION/EXPOSURE 
- Induction schedule: 3 identical inductions on days 0, 7, and 14:   6 hour occlusive patch (left side), 0.3 ml undiluted; then removal of  residual test material   assessment 30 hours after each administration
- Challenge schedule: day 28   two 6 hour occlusive patches (right side), one with 0.3 ml test  substance and one with vehicle   subsequent removal of residual test material   assessments 30 and 54 hours after administration
- Concentrations used for challenge: undiluted (100 %)
- Positive control:   alpha-hexylcinnamaldehyde (CAS No. 101-86-0) (not concurrent)   
Bühler test with 20 test and 10 control animals   
Occlusive epicutaneous induction, undiluted   
Occlusive epicutaneous challenge with 50 % in corn oil
EXAMINATIONS
- Grading system: Magnusson and Kligman
- Pilot study: determination of slightly and not skin irritating  concentrations dermal concentrations: 5; 25; 50; 100 % w/w  
 3 animals each with 4 different concentrations (0.3 ml each) at  different sites   
6 hour occlusive patch test followed by removal of residual test  material assessment of dermal reactions 30 and 54 hours after administration
- Additional (and identical except for increased body weights) pilot  study during week 4; reason: Increase in body weight might cause  differences in skin sensitivity
Challenge controls:
corn oil
Positive control substance(s):
not specified
Remarks:
alpha-hexylcinnamaldehyde (CAS No. 101-86-0) (not concurrent)   Bühler test with 20 test and 10 control animals   Occlusive epicutaneous induction, undiluted   Occlusive epicutaneous challenge with 50 % in corn oil, checked from 11-24-1997 to 24-12-1997

Results and discussion

Positive control results:
Positive control: 10/20 test animals positive 30 hours after challenge,  no control animal positive

In vivo (non-LLNA)

Resultsopen allclose all
Key result
Reading:
1st reading
Hours after challenge:
30
Group:
test group
Dose level:
100%
No. with + reactions:
0
Total no. in group:
20
Clinical observations:
no
Key result
Reading:
2nd reading
Hours after challenge:
54
Group:
test group
Dose level:
100%
No. with + reactions:
0
Total no. in group:
20
Clinical observations:
no
Key result
Reading:
1st reading
Hours after challenge:
30
Group:
negative control
Dose level:
100%
No. with + reactions:
0
Total no. in group:
10
Clinical observations:
no
Key result
Reading:
2nd reading
Hours after challenge:
54
Group:
negative control
Dose level:
100%
No. with + reactions:
0
Total no. in group:
10
Clinical observations:
no
Key result
Reading:
1st reading
Hours after challenge:
30
Group:
positive control
Dose level:
50 %
No. with + reactions:
10
Total no. in group:
20
Clinical observations:
effects on skin
Remarks on result:
other: see above
Remarks:
"Positive Control substance(s)

Any other information on results incl. tables

RESULTS OF PILOT STUDY: None of the applied test substance concentrations  caused primary skin irritation in any of the two pilot 

studies 30 or 54  hours after administration.
RESULTS OF TEST
- Sensitization reaction: No signs of dermal irritation were observed in  the application areas of test and control animals 30 and 54 hours after  administration.
- Clinical signs: No systemic effects were detected during the  observation period.
  1st, 2nd, and 3rd induction: No signs of skin irritation were observed  in the application areas of test and control animals 30 hours after  application.
- Positive control: 10/20 test animals positive 30 hours after challenge,  no control animal positive
- Other: The overall mean body weight increase of 250 g (test group) /  249 g (control group) is normal: no treatment related effect.

Applicant's summary and conclusion

Conclusions:
Under the conditions of the Buehler test, the test item showed no evidence of sensitisation.
Executive summary:

The test substance was tested for skin sensitisation in guinea pigs by the Buehler method.

To determine the potential sensitising effect of this test substance, 20 test animals and 10 control animals as well as an accompanying group of 3 animals were used for the test. 30 and 54 hours after challenge treatment all skin reactions were observed and recorded according to the Magnusson und Kligman grading scale for evaluation of challenge patch test reaction. The test undiluted substance did not cause any skin irritations in a preliminary study. The 100 % test compound was used for the induction period. The concentration used for challenge exposure, the highest non-irritating and nontoxic dose, was identified in the 4th week of the test on the animals of the accompanying group, same age as the animals in the main test. On this basis and based on the results from the induction period, the undiluted test substance was administered for challenge treatment.

During the test, no systemic effects and no impairment of body weight gain due to the test substance were observed in the test and control animals. 30 hours after all three inductions the dermal treatment with the test substance did not cause any skin reactions in the test animals. The control animals treated with the vehicle during the induction periods also showed no signs of skin irritation 30 hours post applicationem (p.a.).

The challenge treatment with the undiluted test compound did not cause any cutaneous reactions on the posterior right flank of any animal in the test and control groups 30 and 54 hours after administration. Neither did the vehicle-laden patch lead to skin reactions in any animal of the test and control groups.

Under the conditions of the Buehler test, the test item showed no evidence of sensitisation.