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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:
guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2002
Report date:
2002

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to guideline
Guideline:
OECD Guideline 406 (Skin Sensitisation)
Qualifier:
according to guideline
Guideline:
EPA OPPTS 870.2600 (Skin Sensitisation)
GLP compliance:
yes
Remarks:
US EPA GLPs (40 CFR, Part 792) and OECD GLPs
Type of study:
Buehler test
Justification for non-LLNA method:
The study was conducted prior to the LLNA becoming the preferred method.

Test material

Constituent 1
Chemical structure
Reference substance name:
4-(α,α-dimethylbenzyl)phenol
EC Number:
209-968-0
EC Name:
4-(α,α-dimethylbenzyl)phenol
Cas Number:
599-64-4
Molecular formula:
C15H16O
IUPAC Name:
4-(α,α-dimethylbenzyl)phenol
Details on test material:
p-Cumylphenol (PCP, CAS #599-64-4)Purity = 99%

In vivo test system

Test animals

Species:
guinea pig
Strain:
Hartley
Sex:
male/female
Details on test animals and environmental conditions:
Male and female albino Hartley guinea pigs were received from Elm Hill Breeding Labs, Inc. They were 373.6 to 437.8 g and at least 21 days of age. They were group-housed upon arrival in stainless steel suspended cages. The animals were acclimated for at least 5 days prior to dosing. Water and feed were provided ad libitum. The temperature during the test period was 68 ± 5 degrees F with a relative humidity range of 30 to 70 %. Room lights were on a 12-hour light/dark cycle.

Study design: in vivo (non-LLNA)

Induction
Route:
epicutaneous, occlusive
Vehicle:
other: 80% Ethanol
Concentration / amount:
0.4 g
Challenge
Route:
epicutaneous, occlusive
Vehicle:
other: Acetone
Concentration / amount:
0.4 g
No. of animals per dose:
- Experimental: 10/sex
- Negative Controls: 5/sex
- Positive Controls: 3 males and 2 females
- Preliminary Irritation: 1 male and 2 females
Details on study design:
Before each application of the test or control substance, the animals were clipped and shaved or depilated on the scapula region in an area of about 3 x 4 cm.

A preliminary irritancy test was conducted, in which it was determined that 0.4 g PCP moistened with 80 % Ethanol was the highest non-irritating concentration.

For the main study, for the induction phase, closed patches for the experimental group were prepared with the PCP moistened with 80 % Ethanol and were applied directly to the skin and covered with a gauze pad of approximately 4 to 6 cm². The patch was kept in place with occlusive bandaging. The patch was removed after 6 hours of exposure and any residual PCP was wiped off with a gauze pad. The test substance was applied once per week for 3 consecutive weeks (Days 0, 7 and 14) on one side of the animal. The positive control substance (dinitrochlorobenzene, DNCB) was applied in the same manner. Naive animals, i.e., untreated during the induction phase, served as a negative control group.

On the day of the challenge, a 4 x 3 cm virgin skin site was shaved on the flanks of the experimental and control animals. The challenge test was performed in the same way as the 6-hour closed patch test of the induction phase. The skin was exposed to PCP for 6 hours. The concentration used at challenge was the highest non-irritating dose determined in the Preliminary Irritation Study. At approximately 21 hours after removal of the challenge dose, the area of the challenge was marked and the whole back shaved. Approximately three hours after shaving, the test site was examined for erythema and oedema. The reaction was graded according to the Magnusson and Kligman Grading Scale for the Evaluation of Challenge Patch Test Reactions. Reading of the skin area was repeated at approximately 48 hours after removal of the challenge dose and the skin reactions were graded.

0 = No reactions
1 = discrete or patchy erythema
2 = moderate and confluent erythema
3 = intense erythema and swelling
Challenge controls:
- Negative Controls: 5 per sex
- Positive Controls: 3 males and 2 females
Positive control substance(s):
yes
Remarks:
Dinitrochlorobenzene (DNCB)

Results and discussion

Positive control results:
Following the challenge application of 0.1 % DNCB to the test animals, 5 of 5 animals developed moderate to intense erythema and oedema within 24 hours. All animals continued to exhibit discrete to moderate erythema and discrete to intense oedema through 48 hours.

In vivo (non-LLNA)

Resultsopen allclose all
Key result
Reading:
1st reading
Hours after challenge:
24
Group:
test chemical
Dose level:
0.4 g
No. with + reactions:
0
Total no. in group:
20
Clinical observations:
none
Remarks on result:
no indication of skin sensitisation
Key result
Reading:
2nd reading
Hours after challenge:
48
Group:
test chemical
Dose level:
0.4 g
No. with + reactions:
0
Total no. in group:
20
Clinical observations:
none
Remarks on result:
no indication of skin sensitisation
Reading:
1st reading
Hours after challenge:
24
Group:
negative control
Dose level:
0 g
No. with + reactions:
0
Total no. in group:
10
Clinical observations:
none
Remarks on result:
no indication of skin sensitisation
Reading:
2nd reading
Hours after challenge:
48
Group:
negative control
Dose level:
0 g
No. with + reactions:
0
Total no. in group:
10
Clinical observations:
none
Remarks on result:
no indication of skin sensitisation
Reading:
1st reading
Hours after challenge:
24
Group:
positive control
Dose level:
0.1 %
No. with + reactions:
5
Total no. in group:
5
Clinical observations:
none
Remarks on result:
positive indication of skin sensitisation
Reading:
2nd reading
Hours after challenge:
48
Group:
positive control
Dose level:
0.1%
No. with + reactions:
5
Total no. in group:
5
Clinical observations:
none
Remarks on result:
positive indication of skin sensitisation

Applicant's summary and conclusion

Interpretation of results:
other: Not classified in accordance with EU criteria
Conclusions:
Under the conditions of this study, PCP was not a skin sensitiser.
Executive summary:

The skin sensitisation potential was investigated in a study performed per OECD Test Guideline 406 and EPA OPPTS 870.2600 under GLP conditions.

Male and female albino Hartley guinea pigs were exposed to the test substance in 80 % Ethanol (induction phase) or Acetone (challenge phase) during a Buehler test.

Under the conditions of this study, PCP was not a skin sensitiser.