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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:
March, 15th - May, 12th 2000
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2000
Report Date:
2000

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to
Guideline:
OECD Guideline 406 (Skin Sensitisation)
Deviations:
no
Qualifier:
according to
Guideline:
EU Method B.6 (Skin Sensitisation)
Deviations:
no
GLP compliance:
yes
Type of study:
guinea pig maximisation test
Justification for non-LLNA method:
An LLNA study was not performed because there is an existing reliable study for skin sensitisation using the Guinea Pig Maximisation test method. Furthermore, the LLNA test method is not considered to be suitable for fatty alcohols. Please refer to the attached document for further details.

Test material

Reference
Name:
Unnamed
Type:
Constituent
Test material form:
solid

In vivo test system

Test animals

Species:
guinea pig
Strain:
Dunkin-Hartley
Sex:
female
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: Harlan Nossan S.r.l., Correzzana (MI), Italy
- Age at study initiation: 5 -6 weeks
- Weight at study initiation: 672.9 ± 61.9 g (control), 629.9 ± 62.0 g (test group)
- Housing: stainless steel cages (48x63x41 cm) with a grid floor in groups of 5 animals
- Diet: commercially available laboratory diet (Altromin MSK) ad libitum
- Water: drinking water ad libitum
- Acclimation period: at least 5 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 20 - 24
- Humidity (%): 45 - 65
- Air changes (per hr): no data
- Photoperiod (hrs dark / hrs light): 12/12

IN-LIFE DATES: From: 2000-03-15 To: 2000-05-12

Study design: in vivo (non-LLNA)

Induction
Route:
intradermal and epicutaneous
Vehicle:
corn oil
Concentration / amount:
5% test substance in vehicle or Freund's complete adjuvant for intradermal induction
75% test substance in vehicle for topical induction
10% test substance in vehicle for challenge
Challenge
No.:
#1
Route:
epicutaneous, occlusive
Vehicle:
corn oil
Concentration / amount:
5% test substance in vehicle or Freund's complete adjuvant for intradermal induction
75% test substance in vehicle for topical induction
10% test substance in vehicle for challenge
No. of animals per dose:
Range finding: 2 for injection tolerance test, 5 for topical tolerance test
Main test: 10 for test group, 5 for control group
Details on study design:
RANGE FINDING TESTS:
Intradermal injection tolerance test: 0.1 ml of the test item in concentrations of 10, 5, 1, 0.5, 0.1 and 0.05% in vehicle injected intradermally, evaluation after 6 days
Topical application tolerance test: with 0.1 ml of emusified Freund's complete adjuvant (FCA) intradermally injected animals (2 injections) were treated topically for 24 hrs (epicutaneous, occlusive, duplicate application) after 8 days with concentrations of 75, 50, 20, 10 and 5% test substance in vehicle, evaluation 24 and 48 hours after removal of dressings

MAIN STUDY
A. INDUCTION EXPOSURE
- No. of exposures: 2
- Exposure period:
Intradermal: single application, skin reactions assessed approx. 24 hrs after injection
Epicutaneous: 48 hrs, evaluation 24 hrs after patch removal
- Test groups:
Intradermal: 3 pairs of injections (0.1 ml each) at anterior, median and posterior positions; anterior: emulsified FCA, median: test substance in corn oil, posterior: test substance in emulsified FCA
Epicutaneous: 0.4 ml of test substance in corn oil (the day before 0.5 ml of sodium lauryl sulphate at 10% concentration was spread evenly over the skin surrounding the injections sites)
- Control group: Animals of the control group were treated in the same manner except that the test item was replaced by vehicle alone
- Site:
Intradermal: scapular region over an area approx. 20 x 40 mm, all injections were made at the edge of the prepared site and the anterior and median injections were positioned close together and distant from the posterior injections
Epicutaneous: gauze patches were covered with the test solutions (0.4 ml each) and placed over the injection sites, this was covered with strips of aluminium foils and the animals were then wrapped with lengths of elastic adhesive bandages
- Frequency of applications: Day1: intradermal injections, Day7: pretreatment with sodium lauryl sulphate, Day8: epicutaneous application
- Duration: 3 weeks
- Concentrations:
Intradermal: 5% in corn oil, 5% in emulsified FCA
Epicutaneous: 75% in corn oil

B. CHALLENGE EXPOSURE
- No. of exposures: 1
- Day(s) of challenge: Day 22
- Exposure period: 24 hrs
- Test groups: 0.2 ml aliquots of the test substance in corn oil on patches of gauze measuring 20x20 mm were applied on the right flank of each animal, the left flank of each animal was similarly treated with 0.2 ml of vehicle (petrolatum) alone
- Control group: same treatment as test substance animals
- Site: clipped flanks, area approx. 50x50 mm on each flank
- Concentrations: 10% in corn oil
- Evaluation: 48 and 72 hrs after challenge (24 and 48 hrs after removal of dressings)
Positive control substance(s):
yes
Remarks:
Mercaptobenzothiazole

Results and discussion

Positive control results:
Most recent reliability check performed in September/October 1999.
Concentrations:
Induction: 1% positive control substance in PEG 400 (injection); 50% positive control substance in acetone (topical)
Challenge: 25% positive control substance in acetone

100% response in test group and 0% response in control group at challenge: test system regarded as valid.

In vivo (non-LLNA)

Resultsopen allclose all
Key result
Reading:
1st reading
Hours after challenge:
48
Group:
test group
Dose level:
10%
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:
48
Group:
negative control
Dose level:
10%
No. with + reactions:
0
Total no. in group:
5
Remarks on result:
no indication of skin sensitisation
Reading:
2nd reading
Hours after challenge:
72
Group:
test group
Dose level:
10%
No. with + reactions:
0
Total no. in group:
10
Remarks on result:
no indication of skin sensitisation
Reading:
2nd reading
Hours after challenge:
72
Group:
negative control
Dose level:
10%
No. with + reactions:
0
Total no. in group:
5
Remarks on result:
no indication of skin sensitisation
Reading:
1st reading
Hours after challenge:
24
Group:
positive control
Dose level:
25% positive control substance in acetone
No. with + reactions:
5
Total no. in group:
5
Remarks on result:
positive indication of skin sensitisation
Reading:
2nd reading
Hours after challenge:
48
Group:
positive control
Dose level:
25% positive control substance in acetone
No. with + reactions:
5
Total no. in group:
5
Remarks on result:
positive indication of skin sensitisation

Applicant's summary and conclusion

Interpretation of results:
GHS criteria not met
Conclusions:
The test item does not elicit a sensitisation response in the guinea pig, there being no reaction observed at challenge.
Executive summary:

The potential of the test item, NAFOL 2022, to induce and elicit delayed dermal sensitisation was assessed by a guinea pig model using the maximisation test of Magnusson and Kligman.

The concentrations of the test item used in the main study were determined by the results of preliminary screening tests. The main sensitisation test was undertaken using a test group of 10 animals and a control group of 5 animals. In an attempt to induce sensitisation, test animals were intradermally injected with an emulsion of Freund's complete adjuvant (FCA) and the test item at 5% concentration in both the selected vehicle and an emulsion of FCA. One week later this was boosted by topical application of the test item at 75% concentration over the injection sites. Control group animals were treated in the same manner but the selected vehicle (corn oil) was used in place of the test item. Two weeks after the second induction stage, all animals were challenged by topical application of both the vehicle (petrolatum) and the test item at 10% concentration.

At challenge no response to the test item was observed in any animal of the test or control groups following topical exposure to the test item at 10% concentration. No reaction to the vehicle alone was observed in any animal of test or control groups.

These results indicate that the test item, NAFOL 2022, does not elicit a sensitisation response in the guinea pig, there being no reaction observed at challenge.