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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
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1991
Report Date:
1991

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
EU Method B.6 (Skin Sensitisation)
GLP compliance:
yes
Type of study:
guinea pig maximisation test
Justification for non-LLNA method:
Currently no LLNA study is available for assessment. The Guinea Pig Maximisation Test (GMPT) has been carried out as an animal test to predict human sensitization for over a decade and is recommended by international test guidelines such as OECD.

Test material

Reference
Name:
Unnamed
Type:
Constituent
Specific details on test material used for the study:
- Analytical purity: 99.7%

In vivo test system

Test animals

Species:
guinea pig
Strain:
other: Pirbright White, Dunkin
Sex:
female
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: Lippische Versuchstierzucht, Hagemann GmbH & Co. KG, Germany
- Weight at study initiation: 294 - 331 g
- Housing: 5 per cage, in Makrolon cages, type IV; bedding: Granulat Typ 3/4 (staubfrei); SSNIFF
- Diet: Kliba 341.4 mm (Kaninchen-Meerschweinchen-Haltungsdiaet), ad libitum
- Water: tap water ad libitum; about 2 g of ascorbic acid per 10 litres were added to the drinking water twice a week
- Acclimation period: at least 7 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 20 - 24°C
- Humidity (%): 30 - 70%
- Air changes (per hr): fully air-conditioned rooms in which a central air-conditioning system
- Photoperiod (hrs dark / hrs light): 12/12



Study design: in vivo (non-LLNA)

Inductionopen allclose all
Route:
intradermal
Vehicle:
water
Remarks:
destilled
Concentration / amount:
5%
Route:
epicutaneous, occlusive
Vehicle:
water
Remarks:
destilled
Concentration / amount:
75%
Day(s)/duration:
48 hours
Challenge
No.:
#1
Route:
epicutaneous, occlusive
Vehicle:
water
Remarks:
destilled
Concentration / amount:
50%
Day(s)/duration:
24 hours
Adequacy of challenge:
highest non-irritant concentration
No. of animals per dose:
Test groups: 10
Control groups: 5
Details on study design:
PRETEST
For detecting a possible influence on irritating effects of previous intradermal treatment with Freund´s adjuvant, animals pretreated with Freund´s adjuvant / 0.9% aqueous NaCl-solution (1:1) each, in the same manner as intradermal induction about 3 weeks prior to the application of the test substance were used. In the preliminary test after two 24-hour percutaneous occlusive applications within 96 hours the minimum irritant concentration was found to be a 75% test substance preparation in aqua bidest. and the maximum non-irritant concentration a 50% test substance preparation in aqua bidest.
Applicability: it was possible to inject a 5% test substance preparation in 0.9% aqueous NaCl-solution resp. in Freund´s adjuvant / 0.9% aqueous NaCl-solution (1:1) with a syringe.

MAIN STUDY
A. INDUCTION:
- Intradermal induction: 6 intradermal injections in groups of two per animal
Injections for the test group:
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.
Injections for control groups 1 and 2: The animals were given the same injections (A, B, C) but without test substance, only with the formulating agent.
- Site of application: shoulder
- Readings: 24 h after the beginning of application
- Assessment of the skin findings: analogous to the pretest
- Percutaneous induction: Percutaneous induction was carried out one week after intradermal induction.
- Amount applied: 2 x 4 cm filter paper strips were applied to the skin of the shoulder under an occlusive dressing. In the case of liquids the filter paper strip was soaked in the test substance formulation; thus, the animals were exposed to about 0.3 g of the test substance formulation. The control animals were not treated since the distilled water used as formulating agent was not expected to influence the result of the study.
- Duration of exposure: 48 hours
- Site of application: shoulder, same area as in the case of the previous intradermal application
- Readings: 48 h after the beginning of application
- Assessment of skin findings: analogous to the pretest

B. CHALLENGE:
- Test concentration: non-irritant concentration (50%) challenge 21 days after intradermal induction.
- Amount applied: 2 x 2 cm filter paper strips were applied to the skin of the flank under an occlusive dressing. In the case of liquids the test filter paper strip was soaked in the test substance formulation; thus the animals were exposed to about 0.15 g of the test substance formulation. Treatment of the test group and of control group 1 with the test substance formulation (control group 2 remained untreated).
- Duration of exposure: 24 hours
- Site of application: intact clipped flank
- Readings: 24 and 48 h after the removal of the patch
- Assessment of skin findings: analogous to the pretest
Challenge controls:
yes
Positive control substance(s):
yes

Results and discussion

In vivo (non-LLNA)

Resultsopen allclose all
Key result
Reading:
1st reading
Hours after challenge:
24
Group:
test group
Dose level:
50%
No. with + reactions:
0
Total no. in group:
10
Clinical observations:
none
Reading:
1st reading
Hours after challenge:
24
Group:
negative control
Dose level:
50%
No. with + reactions:
0
Total no. in group:
5
Clinical observations:
none

Any other information on results incl. tables

After the challenge with the 50% test substance aqueous preparation, no skin reactions could be observed neither in the test animals nor in the animals of control group. Thus, under the present test conditions, the test item diethylene glycol is not a skin sensitizer.

Applicant's summary and conclusion

Interpretation of results:
GHS criteria not met