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Skin sensitisation

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Administrative data

Endpoint:
skin sensitisation: in vivo (non-LLNA)
Type of information:
experimental study
Adequacy of study:
weight of evidence
Study period:
1994-11-08 to 1995-01-16
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1995
Report date:
1995

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to guideline
Guideline:
OECD Guideline 406 (Skin Sensitisation)
Version / remarks:
(July 17th, 1992)
Deviations:
no
Qualifier:
according to guideline
Guideline:
EU Method B.6 (Skin Sensitisation)
Deviations:
no
GLP compliance:
yes (incl. QA statement)
Type of study:
guinea pig maximisation test
Justification for non-LLNA method:
study performed prior to adoption of LLNA guideline

Test material

Constituent 1
Chemical structure
Reference substance name:
Reference substance 002
Cas Number:
288259-40-5
Constituent 2
Chemical structure
Reference substance name:
Water
EC Number:
231-791-2
EC Name:
Water
Cas Number:
7732-18-5
Molecular formula:
H2O
IUPAC Name:
Dihydrogen oxide
Test material form:
liquid
Specific details on test material used for the study:
SOURCE OF TEST MATERIAL
- Source and lot/batch No.of test material: LC 802-3

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: room temperature
- Stability under test conditions: yes stable for study duration

TREATMENT OF TEST MATERIAL PRIOR TO TESTING
- Treatment of test material prior to testing: dilution for induction
- Final dilution of a dissolved solid, stock liquid or gel: 0.01 - 0.5 %

In vivo test system

Test animals

Species:
guinea pig
Strain:
Dunkin-Hartley
Sex:
male
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: Harlan Winkelmann GmbH
- Weight at study initiation: 208 - 319 g
- Housing: individual or in pairs
- Diet (e.g. ad libitum): Altromin 3022, ad libitum
- Water (e.g. ad libitum): tap water, ad libitum
- Acclimation period: at least 5 days


ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22°C ± 3°C
- Humidity (%): 60% ± 20%
- Photoperiod (hrs dark / hrs light): 12/12
- IN-LIFE DATES: From: To: 1994-10-11 (prelim. study) 1994-11-08 (main study) to 1994-12-02

Study design: in vivo (non-LLNA)

Induction
Route:
intradermal and epicutaneous
Vehicle:
physiological saline
Remarks:
0.9%
Concentration / amount:
intracutaneous: 0.5% test substance solution
topical: undiluted test substance
Day(s)/duration:
day 0: intracutaneous injection 0.1 mL; day 7: 48 hours exposure to 2 mL of undiluted testsubstance, topically, semi-occlusive patch (size: approx. 5 x 6 cm²)
Adequacy of induction:
highest concentration used causing mild-to-moderate skin irritation and well-tolerated systemically
Challenge
No.:
#1
Route:
epicutaneous, occlusive
Vehicle:
other: aqueous hydroxypropylmethylcellulose gel
Remarks:
0.8%
Concentration / amount:
0.01% testsubstance solution
Day(s)/duration:
24 hours
Adequacy of challenge:
highest non-irritant concentration
No. of animals per dose:
test group: 10 males
control group: 5 males
Details on study design:
RANGE FINDING TESTS:
A preliminary irritation study was conducted in order to select test substance concentrations to be used in the main study. The selection of concentrations was based on the following criteria:
-The concentrations are well-tolerated systemically by the animals.
-For the induction exposures: the highest possible concentration that produced mild to moderate irritation
-For challenge exposure: the maximum non-irritant concentration.

intracutaneous application 2 animals (0.1, 1, 5, 10 50 100%)
topical application 6 animals (0.01, 0.1, 1, 10, 50 and 100%)

Based on the results, the test substance concentrations selected for the main study were a 0.5% concentration for the intradermal induction and a 100% concentration for the epidermal induction exposure. A 0.01% test substance concentration was selected for the challenge phase.

MAIN STUDY
A. INDUCTION EXPOSURE INTRADERMAL
- No. of exposures: 1
- Test groups: (1) 0.1 mlLFreund's adjuvant (diluted 1: 1 with 0.9% NaCI-solution)
(2) 0.1 mL of the test compound
(3) 0.1 mL of a mixture of the test compound and Freund's adjuvant (1 : 1)
- Control group: animals were treated as described for the experimental animals except that, instead of the test substance, vehicle alone was administered
- Site: scapular region
- Frequency of applications: 1
- Concentrations: 0.5% test substance

B. INDUCTION EXPOSURE INTRADERMAL
- No. of exposures: 1
- Exposure period: 48 h
- Test groups: 2 mL undiluted test substance
- Control group: vehicle
- Site: shoulder region
- Frequency of applications: 1
- Duration: 48 h
- Concentrations: 100%

C. CHALLENGE EXPOSURE
- No. of exposures: 1
- Day(s) of challenge: 21
- Exposure period: 24 h
- Test groups: left flank: 2 mL 0.01% test substance in 0.8% aqueous hydroxypropyl-methylcellulose gel; right flank: vehicle
- Control group: 2left flank: 2 mL 0.01% test substance in 0.8% aqueous hydroxypropyl-methylcellulose gel; right flank: vehicle
- Concentrations: 0.01% testsubstance
- Evaluation (hr after challenge): 24, 48, 72 h
Positive control substance(s):
yes
Remarks:
potassium dichromate

Results and discussion

Positive control results:
The positive control results were obtained from LPT historical background data. The animals of the positive control group (same origin (strain) as those used in the study) had been treated with a 1.0% (wIv) potassium dichromate solution intracutaneously in stage 1, a 1.0% (wIv) potassium dichromate solution topically in stage 2 and a 0.1% (wIv) potassium dichromate solution topically in stage 3.
The animal strain used in this study is sensitive to potassium dichromate. The degree of sensitisation was extreme (17 of 20 animals with positive reaction, one animal died prematurely) and potassium dichromate is classified as a substance with extremely sensitising properties.

In vivo (non-LLNA)

Resultsopen allclose all
Key result
Reading:
1st reading
Hours after challenge:
24
Group:
negative control
Dose level:
0.01%
No. with + reactions:
0
Total no. in group:
5
Remarks on result:
no indication of skin sensitisation
Key result
Reading:
1st reading
Hours after challenge:
24
Group:
test chemical
Dose level:
0.01%
No. with + reactions:
0
Total no. in group:
10
Remarks on result:
no indication of skin sensitisation
Key result
Reading:
1st reading
Hours after challenge:
24
Group:
positive control
Dose level:
0.1%
No. with + reactions:
17
Total no. in group:
19
Clinical observations:
one animal died prematurely (stress related)
Remarks on result:
positive indication of skin sensitisation
Key result
Reading:
2nd reading
Hours after challenge:
48
Group:
negative control
Dose level:
0.01%
No. with + reactions:
0
Total no. in group:
5
Remarks on result:
no indication of skin sensitisation
Key result
Reading:
2nd reading
Hours after challenge:
48
Group:
test chemical
Dose level:
0.01%
No. with + reactions:
0
Total no. in group:
10
Remarks on result:
no indication of skin sensitisation

Applicant's summary and conclusion

Interpretation of results:
GHS criteria not met
Conclusions:
Polyoxyethylene(4.5) lauryl miristyl ether carboxylic acid is not a dermal sensitiser in this study.
Executive summary:

In a dermal sensitisation study according to OECD Guideline 406 (adopted 17th July 1992) and EU method B.6 (1992) with Polyoxyethylene(4.5) lauryl miristyl ether carboxylic acid (90% a.i.) in hydroxypropyl-methylcellulose gel, young adult male Dunkin-Hartley guinea pigs (10 in test group, 5 in control group) were tested using the method of Magnusson and Kligman. Potassium dichromate was used as positive control.

Based on the results of a preliminary study, the test substance concentrations selected for the main study were a 0.5% concentration (in 0.9% NaCl solution) for the intradermal induction and a 100% concentration for the epidermal induction exposure. A 0.01% test substance concentration (in 0.8% aqueous hydroxypropyl-methylcellulose gel) was selected for the challenge phase.

After epidermal induction all animals of the experimental group showed signs of irritation. Following a challenge exposure to a 0.01% test substance concentration, no skin reactions were evident in the control animals and animals of the test group (24, 48 and 72 h readings). The sensitisation rate was 0%.

According to CLP, EU GHS (Regulation (EC) No 1272/2008), a response of at least 30% of the test animals of an adjuvant type guinea pig test method for skin sensitisation is considered as positive.

Polyoxyethylene(4.5) lauryl miristyl ether carboxylic acid is not a dermal sensitiser in this study.