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Toxicological information

Skin sensitisation

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Administrative data

Endpoint:
skin sensitisation: in vivo (non-LLNA)
Type of information:
migrated information: read-across based on grouping of substances (category approach)
Adequacy of study:
key study
Study period:
1984-10-24 to 1984-12-20
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: This study is classified as reliable without restriction because it was conducted according to or similar to OECD TG 406.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1987
Report Date:
1987

Materials and methods

Test guideline
Qualifier:
equivalent or similar to
Guideline:
OECD Guideline 406 (Skin Sensitisation)
GLP compliance:
yes
Type of study:
Buehler test
Justification for non-LLNA method:
The first-choice method according to REACH Annex VII §8.3, the Murine Local Lymph Node Assay, is known to give false positive results with hydrocarbon substances.

Test material

Reference
Name:
Unnamed
Type:
Constituent
Type:
Constituent
Test material form:
other: Oily liquid
Details on test material:
- Name of test material (as cited in study report): white mineral oil [F-52-01; ARCOprime 70]
- Molecular formula (if other than submission substance): N/A
- Molecular weight (if other than submission substance): N/A
- Smiles notation (if other than submission substance): N/A
- InChl (if other than submission substance): N/A
- Structural formula attached as image file (if other than submission substance): see Fig. N/A
- Substance type: petroleum hydrocarbons
- Physical state: transparent colourless liquid
- Analytical purity: 100% petroleum hydrocarbons
- Impurities (identity and concentrations): not reported
- Composition of test material, percentage of components: not reported
- Isomers composition: not reported
- Purity test date: not reported
- Lot/batch No.: 769
- Expiration date of the lot/batch: September 1989
- Radiochemical purity (if radiolabelling): N/A
- Specific activity (if radiolabelling): N/A
- Locations of the label (if radiolabelling): N/A
- Expiration date of radiochemical substance (if radiolabelling): N/A
- Stability under test conditions: approximately 5 years
- Storage condition of test material: stored in temperature-monitored room (10 to 27 degrees Celsius)
- Density 0.8433 g/ml
- Flash Point °F: 355

In vivo test system

Test animals

Species:
guinea pig
Strain:
Hartley
Sex:
male
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: CAMM Research Laboratory Animals
- Age at study initiation: young adult
- Weight at study initiation: 314.4 ± 22.6 grams
- Housing: housed individually in stainless steel cages
- Diet (e.g. ad libitum): ad libitum
- Water (e.g. ad libitum): ad libitum
- Acclimation period: 14 days


ENVIRONMENTAL CONDITIONS
- Temperature (°C): 19 to 22 degrees Celsius
- Humidity (%): 28 to 70%
- Air changes (per hr): not reported
- Photoperiod (hrs dark / hrs light): 12 hours light/dark


IN-LIFE DATES: From: 1984-10-24 To: 1984-12-20

Study design: in vivo (non-LLNA)

Inductionopen allclose all
Route:
epicutaneous, occlusive
Vehicle:
unchanged (no vehicle)
Concentration / amount:
0.5 millilitres of undiluted test material [highly refined base oil; F-52-01] and 0.3% DNCB in 80% ethanol/water (induction phase) and 0.2% DNCB in 80% ethanol/water (challenge phase)
Challengeopen allclose all
Route:
epicutaneous, occlusive
Vehicle:
unchanged (no vehicle)
Concentration / amount:
0.5 millilitres of undiluted test material [highly refined base oil; F-52-01] and 0.3% DNCB in 80% ethanol/water (induction phase) and 0.2% DNCB in 80% ethanol/water (challenge phase)
No. of animals per dose:
6 males in the irritation phase
8 males induction/challenge phase
4 males challenge control
Details on study design:
RANGE FINDING TESTS: In the dose selection (irritation) study six guinea pigs were administered 0.5 millilitre aliquots of undiluted test article and dilutions 1:2, 1:4, and 1:8 in USP mineral oil to shaved areas of the skin and occlusively wrapped. After 6 hours, the wrapping was removed and the skin was wiped. Twenty-four and 48 hours post-treatment the skin was scored using the Draize scoring method. Based on these findings, the highest non-irritating concentration was selected for use during the challenge phase. A primary irritation score of 0.0 to 0.9 is considered non-irritating.

MAIN STUDY
A. INDUCTION EXPOSURE
- No. of exposures: 3
- Exposure period: 6 hours
- Test groups: white mineral oil [F-52-01] test group [n=10]
- Control group: 0.3% DNCB positive control group [n=10]
- Site: strip of skin along the dorsal midline
- Frequency of applications: once a week
- Duration: 3 weeks
- Concentrations: 0.5 millilitres of undiluted test article and 0.3% DNCB in 80% ethanol/water


B. CHALLENGE EXPOSURE
- No. of exposures: 1
- Day(s) of challenge: 14 days after induction exposure
- Exposure period: 6 hours
- Test groups: white mineral oil [F-52-01] test group [n=10]
- Control group: white mineral oil [F-52-01] challenge control [n=4]; 0.2% DNCB positive control [n=10]; 0.2% DNCB challenge control [n=4]
- Site: naive site on the skin flanking the dorsal midline
- Concentrations: 0.5 millilitres of undiluted test article and 0.2% DNCB in 80% ethanol water
- Evaluation (hr after challenge): 24 and 48 hours


OTHER:
Challenge controls:
F-52-01 challenge control (0.5 millilitres of undiluted test article]
0.2% DNCB in 80% ethanol/water challenge control (0.5 millilitres)
Positive control substance(s):
yes
Remarks:
2,4 dinitrochlorobenzene (2,4 DNCB)

Results and discussion

Positive control results:
Challenge treatment 1 did not induce a strong positive sensitizing response and the positive challenge control did not induce any positive response. Researches realized that this was due to technician error in mixing the DNCB with ethanol and water. A fresh batch of positive control was made and in challenge treatment 2 the positive control group induced a strong positive response, indicating that DNCB is a delayed contact sensitizer. The positive control had a higher response grade and severity index than the DNCB challenge control, substantiating the claim that DNCB is a delayed contact sensitizer.

In vivo (non-LLNA)

Resultsopen allclose all
Reading:
other: Challenge phase 2
Hours after challenge:
48
Group:
test group
Dose level:
0.5 undiluted test material
No. with + reactions:
1
Total no. in group:
10
Clinical observations:
severity index= 0.1
Remarks on result:
other: Reading:
Reading:
other: Challenge phase
Hours after challenge:
48
Group:
negative control
Dose level:
0.5 mL undiluted test material
No. with + reactions:
0
Total no. in group:
4
Clinical observations:
severity index= 0.0
Remarks on result:
other: Reading:
Reading:
other: Challenge phase 2
Hours after challenge:
48
Group:
positive control
Dose level:
0.2% DNCB
No. with + reactions:
10
Total no. in group:
10

Any other information on results incl. tables

Summary of challenge 2 scores

Test and Control Group

Time

Response Grades

Incidence

Severity

0

1

2

3

4

5

6

F-52-01

24 hours

9

1

0

0

0

0

0

1/10

0.1

48 hours

9

1

0

0

0

0

0

F-52-01 Challenge Control

24 hours

4

0

0

0

0

0

0

0/4

0.0

48 hours

4

0

0

0

0

0

0

Positive Control 0.2% DNCB

24 hours

0

0

0

2

5

2

1

10/10

4.2 to 4.4

48 hours

0

0

1

0

3

6

0

0.2% DNCB Challenge Control

24 hours

2

1

1

0

0

0

0

3/4

0.8

48 hours

1

3

0

0

0

0

0

Applicant's summary and conclusion

Interpretation of results:
not sensitising
Remarks:
Migrated information Criteria used for interpretation of results: EU
Conclusions:
Under the conditions of this study, no significant increased response to Highly refined base oil was observed at challenge treatment 2 compared to induction treatment. The response of the treatment animals was similar to the response of the F-52-01 challenge control group. Based on these findings, Highly refined base oil [F-52-01] is not a delayed contact dermal sensitizer.
Executive summary:

In a skin sensitisation study, male guinea pigs were used in irritation, induction, and challenge tests to determine if Highly refined base oil is a delayed dermal sensitizer. During the induction phase, 0.5 mL of undiluted test article (F-52-01 test group; n=10) or 0.3% DNCB in 80% ethanol/water (positive control test group; n=10) was applied to a shaved area along the dorsal midline and removed after 6 hours. This procedure was performed once a week every three weeks. Fourteen days after the last induction dose was applied, the positive control test group (n=10), the F-52 -02 test group (n=10), the F-52 -01 challenge control group (n=4), and the 0.2% DNCB challenge control group (n=2) were administered either 0.5 mL of undiluted White mineral oil [F-52 -01] or 0.2% DNCB in 80% ethanol/water on naive test sites. The patches were removed after 6 hours of exposure and the challenge sites were scored at 24 and 48 hour post-application.

No significant increased response to white mineral oil was observed at challenge treatment 2 compared to induction treatment. The response of the treatment animals was similar to the response of the F-52-01 challenge control group. Based on these findings and under the conditions of this study, Highly refined base oil is not a delayed contact dermal sensitizer. DNCB induced a delayed contact sensitizing response in challenge treatment 2. The positive control group had response grades and a severity index that was higher than the DNCB challenge control group, which substantiated the positive control group results.

This study received a Klimisch score of 1and is classified as reliable without restriction because it was carried out according to or similar to OECD TG 406.