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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:
1983-09-23 to 1983-10-31
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 guideline study OECD TG 406.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1983
Report Date:
1984

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: semi-solid
Details on test material:
- Name of test material (as cited in study report): Vacuum Residuum (API 81-13) CAS No. 64741-56-6
- Substance type: Bitumen
- Physical state: Black tarry semi-solid
- Composition of test material,
weight percentage of components: Sample API 81-13: 4.46% sulphur, 0.51% nitrogen, 90+% carbon; 6.5% asphaltenes
<1 ppm copper, 33 ppm iron, 39 ppm vanadium, 18 ppm nickel
- Lot/batch No.: API 81-13
- Expiration date of the lot/batch: not reported
- Stability under test conditions: not reported
- Storage condition of test material: Stored at room temperature in original containers
- Other:Sample 81-13 was selected because of its high sulphur and asphaltene contents
- Distillation (ASTM D 11-60) °F- Initial Boiling Point 650
- Gravity API: 6.6

In vivo test system

Test animals

Species:
guinea pig
Strain:
Hartley
Sex:
male
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: Hazleton Dutchland Inc., Denver, Pennsylvania
- Age at study initiation: Young adult
- Weight at study initiation: Between 382 to 499 grams
- Housing: Individual screen-bottom cages
- Diet (e.g. ad libitum): Ad libitum
- Water (e.g. ad libitum): Ad libitum
- Acclimation period: 14 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22 to 26 degrees Celsius
- Humidity (%): 42% to 72%
- Air changes (per hr): no data
- Photoperiod (hrs dark / hrs light): 12 hours dark/ 12 hours light

IN-LIFE DATES: From: 09/08/83 To: 09/23/83

Study design: in vivo (non-LLNA)

Inductionopen allclose all
Route:
epicutaneous, occlusive
Vehicle:
unchanged (no vehicle)
Concentration / amount:
0.4 mL
Challengeopen allclose all
Route:
epicutaneous, occlusive
Vehicle:
unchanged (no vehicle)
Concentration / amount:
0.4 mL
No. of animals per dose:
10 animals per dose; 20 animals were in the positive control group.
Details on study design:
RANGE FINDING TESTS: Yes, no description

MAIN STUDY
A. INDUCTION EXPOSURE
- No. of exposures: Three
- Exposure period: 6 hours each exposure
- Test groups: Test substance
- Control group: 2,4-dinitrochlorobenzene at a concentration of 0.3% in 80% in ethanol/distilled water
- Site: Left flank
- Frequency of applications: One application
- Duration: Three weeks
- Concentrations: 0.4 mL

B. CHALLENGE EXPOSURE
- No. of exposures: One
- Day(s) of challenge: One
- Exposure period: 6 hours
- Test groups: 10 test animals and 10 (previously untreated control animals were treated with the test material)
- Control group: Positive control group was treated in the same manner as the treatment group, at a concentration of 0.1% w/v/ acetone
- Site: Right flank
- Concentrations: 0.4 mL

OTHER: The test material was applied to a pad, then applied to the test area with a dental dam and Elastoplast tape. Paraffin oil was used as a solvent to remove residual test material after each application. Due to severe irritation present at the test site for the positive control animals, the third sensitizing dose was applied to a test site, slight posterior to the initial test site.
Challenge controls:
Positive controls were treated in the same manner as the treatment test group with 0.1% w/v in acetone.
Positive control substance(s):
yes
Remarks:
2,4-dinitrochlorobenzene

Results and discussion

Positive control results:
All 20 animals reacted to the 2,4-Dinitrochlorobenzene (DNCB) in the sensitising and challenge phases of the study. The animals experienced slight to moderate reactions to the 0.1% w/v concentration of the DNCB in acetone.

In vivo (non-LLNA)

Resultsopen allclose all
Reading:
other: Sensitising Phase erythema
Group:
test group
Dose level:
0.4 mL undiluted
No. with + reactions:
9
Total no. in group:
10
Remarks on result:
other: Reading:
Reading:
other: Sensitizing Phase Edema
Group:
test group
Dose level:
0.4 mL undiluted
No. with + reactions:
8
Total no. in group:
10
Remarks on result:
other: Reading:
Reading:
other: Challenge Phase Erythema
Group:
test group
Dose level:
0.4 mL undiluted
No. with + reactions:
0
Total no. in group:
10
Remarks on result:
other: Reading:
Reading:
other: Challenge phase Edema
Group:
test group
Dose level:
0.4 mL undiluted
No. with + reactions:
0
Total no. in group:
10
Remarks on result:
other: Reading:
Reading:
other: Challenge Phase Erythema and Edema
Group:
negative control
Dose level:
0.4 mL undiluted
No. with + reactions:
0
Total no. in group:
10
Remarks on result:
other: Reading:
Reading:
other: Sensitizing Phase Erythema and Edema
Group:
positive control
Dose level:
Three applications 0.3% in 80% EtOH
No. with + reactions:
20
Total no. in group:
20
Remarks on result:
other: Reading:
Reading:
other: Challenge Phase
Group:
positive control
Dose level:
0.1% in Acetone
No. with + reactions:
20
Total no. in group:
20
Remarks on result:
other: Reading:

Applicant's summary and conclusion

Interpretation of results:
not sensitising
Remarks:
Migrated information Based on reactions from challenge dose. Grades of 1 or greater in test animal indicate evidence of sensitization, provided grades of < 1 are seen in the naive control animals. Criteria used for interpretation of results: EU
Conclusions:
Normal body weight gains were recorded for all animals during the study with the exception of weight losses during the last 4 days of the study for three animals. Dermal irritation ranged from very slight to well defined for erythema and very slight for edema during the sensitization phase. No dermal irritation was exhibited by either the test group or naive control animals following the challenge application with the undiluted test material. All 20 animals receiving the positive control material reacted appropriately. Based on these results this test material is not considered to be a skin sensitiser in guinea pigs by the closed patch technique.
Executive summary:

In a dermal sensitisation study using undiluted vaccum residue, 20 young adult male Hartley albino guinea pigs were tested using the method of Buehler. 

 

Normal body weight gains were recorded for all animals during the study with the exception of weight losses during the last 4 days of the study for three animals. Dermal irritation ranged from very slight to well defined for erythema and very slight for edema during the sensitisation phase. The high sulfur levels in sample 81 -13 may have attributed to the erythema. No dermal irritation was exhibited by either the test group or naive control animals following the challenge application with the undiluted test material. All 20 animals receiving the positive control material reacted appropriately. Based on these results this test material is not considered to be a skin sensitizer in guinea pigs by the closed patch technique.

 

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