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Diss Factsheets

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:
other: Acceptable, well-documented study report similar or equivalent to OECD 406. GLP.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1990
Report date:
1990

Materials and methods

Test guideline
Qualifier:
equivalent or similar to guideline
Guideline:
OECD Guideline 406 (Skin Sensitisation)
GLP compliance:
yes
Type of study:
Buehler test
Justification for non-LLNA method:
The Buehler skin sensitisation test is a scientifically valid method for assessing skin sensitisation potential. As the data exists and is adequate for hazard assessment, performing a new LLNA test is not scientifically justified.

Test material

Constituent 1
Chemical structure
Reference substance name:
Mono-, and di-(sec-hexadecyl)naphthalene
EC Number:
930-936-3
Molecular formula:
C26H40 + C42H72
IUPAC Name:
Mono-, and di-(sec-hexadecyl)naphthalene
Details on test material:
- Name of test material (as cited in study report): MCP 917
- Physical state: pale yellow liquid
- Storage condition of test material: airtight metal can; stored in a ventilated cabinet at room temperature

In vivo test system

Test animals

Species:
guinea pig
Strain:
Hartley
Sex:
male/female
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: Charles River Kingston, Kingston, NJ 12484
- Age at study initiation: ~ 1 month old
- Weight at study initiation: 326-416 g
- Housing: individually housed in stainless steel cages
- Diet (e.g. ad libitum): ad libitum
- Water (e.g. ad libitum): standard pellet diet, ad libitum
- Acclimation period: at least 12 days

ENVIRONMENTAL CONDITIONS
- Temperature (°F): 65-75
- Humidity (%): 40-60
- Photoperiod (hrs dark / hrs light): 12/12

Study design: in vivo (non-LLNA)

Induction
Route:
epicutaneous, occlusive
Vehicle:
other: Squibb mineral oil (SMO)
Concentration / amount:
0.4 ml, 100% w/w in squibb mineral oil (SMO)
Challenge
Route:
epicutaneous, occlusive
Vehicle:
other: Squibb mineral oil (SMO)
Concentration / amount:
0.4 ml, 75% w/w in squibb mineral oil (SMO)
No. of animals per dose:
Induction and Challenge: 20 guinea pigs
Challenge Control: 10 guinea pigs
Positive Control: 10 guinea pigs
Details on study design:
RANGE FINDING TESTS: Four guinea pigs from a previous shipment were randomly treated with four concentrations of the study substance (100%, 75%, 50%, or 25% in SMO). In the evaluation of the irritation potential, the 100% concentration produced no significant dermal response. Therefore, the 100% concentration was chosen as a reasonable induction dose and as an exaggerated human exposure.

MAIN STUDY
A. INDUCTION EXPOSURE
- No. of exposures: 3
- Exposure period: 6 hours
- Test group: Induction group (20 animals)
- Site: Back
- Frequency of applications: once per week
- Duration: 3 weeks
- Concentrations: 0.4 ml, neat


B. CHALLENGE EXPOSURE
- No. of exposures: 1
- Day(s) of challenge: 14 days post-induction
- Exposure period: 6 hrs
- Test groups: Induction group (20 animals)
- Control group: Naive group (10 animals)
- Site: back
- Concentrations: 0.4 ml, 75% in SMO
- Evaluation (hr after challenge): 24 hours with additional depilation and 48 hours without additional depilation
Challenge controls:
a naive control group
Positive control substance(s):
yes
Remarks:
DNCB

Results and discussion

Positive control results:
The 0.05% w/v concentration of DNCB in acetone has been determined to be the highest non-irritating concentration for challenge. No skin irritation was observed during the induction phase. During the challenge phase, the positive control animals were considered to have been sensitized, based on the test criterion of a minimum of "+2" response for positively-responding animals.

In vivo (non-LLNA)

Resultsopen allclose all
Reading:
1st reading
Hours after challenge:
24
Group:
test chemical
Dose level:
75% w/w in SMO
No. with + reactions:
5
Total no. in group:
19
Remarks on result:
other: Reading: 1st reading. Hours after challenge: 24.0. Group: test group. Dose level: 75% w/w in SMO. No with. + reactions: 5.0. Total no. in groups: 19.0.
Reading:
2nd reading
Hours after challenge:
48
Group:
test chemical
Dose level:
75% w/w in SMO
No. with + reactions:
3
Total no. in group:
19
Remarks on result:
other: Reading: 2nd reading. Hours after challenge: 48.0. Group: test group. Dose level: 75% w/w in SMO. No with. + reactions: 3.0. Total no. in groups: 19.0.
Reading:
1st reading
Hours after challenge:
24
Group:
negative control
Dose level:
75% w/w in SMO
No. with + reactions:
2
Total no. in group:
10
Remarks on result:
other: Reading: 1st reading. Hours after challenge: 24.0. Group: Control group. Dose level: 75% w/w in SMO. No with. + reactions: 2.0. Total no. in groups: 10.0.
Reading:
2nd reading
Hours after challenge:
48
Group:
negative control
Dose level:
75% w/w in SMO
No. with + reactions:
4
Total no. in group:
10
Remarks on result:
other: Reading: 2nd reading. Hours after challenge: 48.0. Group: control group. Dose level: 75% w/w in SMO. No with. + reactions: 4.0. Total no. in groups: 10.0.
Reading:
1st reading
Hours after challenge:
24
Group:
positive control
Dose level:
0.05% w/w DNCB in acetone
No. with + reactions:
5
Total no. in group:
5
Remarks on result:
positive indication of skin sensitisation
Remarks:
Positive control study conducted by testing facility demonstrated that a valid test was performed and indicated that the test design would detect potential contact sensitisers.
Reading:
2nd reading
Hours after challenge:
48
Group:
positive control
Dose level:
0.05% w/w DNCB in acetone
No. with + reactions:
5
Total no. in group:
5
Remarks on result:
positive indication of skin sensitisation
Remarks:
Positive control study conducted by testing facility demonstrated that a valid test was performed and indicated that the test design would detect potential contact sensitisers.

Any other information on results incl. tables

At the 24 hour time point, 5 of 19 animals exposed to the study substance showed positive responses graded as 1 but at the 48 hour time point, 3 of 19 animals. Grade 1 responses were also observed in 2 of 10 naive challenge control animals at the 24 hour time point and 4 of 10 animals at the 48 hour time point. Because the responses were not more severe in the study substance exposed animals than in control animals, these were not considered positive responses. By comparison, 5 of 5 positive control animals exposed to DNCB had responses graded as 2 or more.

Applicant's summary and conclusion

Interpretation of results:
not sensitising
Remarks:
Migrated information
Conclusions:
Based on the results at challenge, the study substance did not induce a sensitisation response in guinea pigs in this study. This finding does not warrant the classification of the study substance as a skin sensitiser under the new Regulation (EC) 1272/2008 on classification, labeling, and packaging of substances and mixtures (CLP) or under the Directive 67/518/EEC for dangerous substances and Directive 1999/45/EC for preparations.
Executive summary:

Hartley Albino guinea pigs were dermally exposed to the study substance neat, 75% or 50% in Squibb mineral oil (SMO). For the challenge phase, the study substance concentration was 75% in SMO. Response grades, severity and incidence at the time of the challenge exposure for the study substance indicated no dermal responsiveness in the induction/challenge group above that observed in the naive challenge control group. Response grades, severity and incidence at the time of the challenge exposure for DNCB resulted in a significantly higher response in the induction/challenge group than that observed in the naive challenge control group. The animals were clinically observed five days per week and no treatment-related changes were noted. Based on the results at challenge, the study substance did not induce a sensitisation response in guinea pigs in this study. This finding does not warrant the classification of the study substance as a skin sensitiser under the new Regulation (EC) 1272/2008 on classification, labeling, and packaging of substances and mixtures (CLP) or under the Directive 67/518/EEC for dangerous substances and Directive 1999/45/EC for preparations.