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Description of key information

Key value for chemical safety assessment

Skin sensitisation

Link to relevant study records
Reference
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other: GLP compliant, guideline study, available as unpublished report, no restrictions, fully adequate for assessment
Qualifier:
according to
Guideline:
OECD Guideline 406 (Skin Sensitisation)
Deviations:
no
GLP compliance:
yes
Type of study:
other: Modified Buehler test
Justification for non-LLNA method:
Predates LLNA
Species:
guinea pig
Strain:
Dunkin-Hartley
Sex:
female
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: David Hall Ltd., Burton-on-Trent, Staffordshire, UK
- Age at study initiation: 7-10 weeks
- Weight at study initiation: 320-395 g
- Housing: In groups of up to 4, in solid-floor polypropylene cages with softwood shavings
- Diet: Guinea Pig FD1 Diet ad libitum, Special Diet Services Ltd., Witham, Essex, UK
- Water: Mains water ad libitum
- Acclimation period: At least 5 days

ENVIRONMENTAL CONDITIONS
- Temperature: 18-21°C
- Humidity: 60-68%
- Air changes (per hr): Approximately 15/hour
- Photoperiod: 12 hrs dark / 12 hrs light

IN-LIFE DATES: From: 13 September 1988 To: 19 October 1988
Route:
epicutaneous, occlusive
Vehicle:
unchanged (no vehicle)
Concentration / amount:
Undiluted for both induction and challenge.
Route:
epicutaneous, occlusive
Vehicle:
unchanged (no vehicle)
Concentration / amount:
Undiluted for both induction and challenge.
No. of animals per dose:
12
Details on study design:
RANGE FINDING TESTS: Yes
- Groups of at least 2 animals were used and up to four different concentrations of the test substance were tested on each animal.

MAIN STUDY
A. INDUCTION EXPOSURE
- No. of exposures: 9
- Exposure period: 6 hours
- Test groups: yes
- Control group: yes
- Site: an area on the shoulder
- Frequency of applications: on days 0, 2, 4, 7, 9, 11, 14 16 and 18
- Concentrations: 0.5 mL of undiluted test material

B. CHALLENGE EXPOSURE
- No. of exposures: 1
- Day(s) of challenge: 10
- Exposure period: 6 hours
- Test groups: yes
- Control group: yes
- Site: an area of flank
- Concentrations: 0.2 mL of undiluted test material
- Evaluation (hr after challenge): Approximately 24 and 48 hours after patch removal
Reading:
1st reading
Hours after challenge:
24
Group:
test group
Dose level:
undiluted test material
No. with + reactions:
0
Total no. in group:
12
Remarks on result:
other: Reading: 1st reading. . Hours after challenge: 24.0. Group: test group. Dose level: undiluted test material. No with. + reactions: 0.0. Total no. in groups: 12.0.
Reading:
2nd reading
Hours after challenge:
48
Group:
test group
Dose level:
undiluted test material
No. with + reactions:
0
Total no. in group:
12
Remarks on result:
other: Reading: 2nd reading. . Hours after challenge: 48.0. Group: test group. Dose level: undiluted test material. No with. + reactions: 0.0. Total no. in groups: 12.0.
Reading:
1st reading
Hours after challenge:
24
Group:
negative control
Dose level:
blank patch
No. with + reactions:
0
Total no. in group:
12
Remarks on result:
other: Reading: 1st reading. . Hours after challenge: 24.0. Group: negative control. Dose level: blank patch. No with. + reactions: 0.0. Total no. in groups: 12.0.
Reading:
2nd reading
Hours after challenge:
48
Group:
negative control
Dose level:
blank patch
No. with + reactions:
0
Total no. in group:
12
Remarks on result:
other: Reading: 2nd reading. . Hours after challenge: 48.0. Group: negative control. Dose level: blank patch. No with. + reactions: 0.0. Total no. in groups: 12.0.
Group:
positive control
Remarks on result:
not measured/tested

Scattered mild redness was commonly seen at the induction sites during the induction phase. Other adverse skin reactions were fissuring, dry, thickened, straw-coloured skin (possible hyperkeratinisation), loss of skin suppleness, superficial cracking of the skin and small superficial scattered scabs. These reactions sometimes precluded evaluation of erythema.

No signs of skin irritation were noted in control animals during induction.

No skin responses were noted in test or control animals at 24 or 48 hours after challenge.

Interpretation of results:
not sensitising
Remarks:
Migrated information
Conclusions:
In a modified (9 induction) Beuhler test in female guinea pigs , there were no skin responses following challenge with undiluted dicyclopentadiene 75%w. Dicyclopentadiene 75% is therefore considered to be non-sensitising to guinea pig skin.
Executive summary:

The sensitization potential of dicyclopentadiene 75% was investigated in female guinea pigs in a modified (9 -induction) Buehler test. The animals were dermally exposed to 0.5 mL undiluted dicyclopentadiene 75% for each of 9 induction phases. Scattered mild redness was commonly seen at the induction sites during the induction phase. Other adverse skin reactions were fissuring, dry, thickened, straw-coloured skin (possible hyperkeratinisation), loss of skin suppleness, superficial cracking of the skin and small superficial scattered scabs. These reactions sometimes precluded evaluation of erythema. Following challenge with 0.2 mL undiluted dicyclopentadiene 75%, no skin responses were noted in test or control animals at 24 or 48 hours after challenge. It is concluded that dicyclopentadiene 75% was a non-sensitiser to guinea pig skin.

Endpoint conclusion
Endpoint conclusion:
no adverse effect observed (not sensitising)
Additional information:

Non human information

In the key study, sensitisation potential of dicyclopentadiene 75% was investigated in female guinea pigs in a modified (9 -induction) Buehler test, according to OECD guideline 406. Guinea pigs were dermally exposed to 0.5 mL undiluted dicyclopentadiene 75% for each of 9 induction phases (Safepharm, 1989e). Scattered mild redness was commonly seen at the induction sites during the induction phase. Other adverse skin reactions were fissuring, dry, thickened, straw-coloured skin (possible hyperkeratinisation), loss of skin suppleness, superficial cracking of the skin and small superficial scattered scabs. These reactions sometimes precluded evaluation of erythema. Following challenge with 0.2 mL undiluted dicyclopentadiene 75%, no skin responses were noted in test or control animals at 24 or 48 hours after challenge. Dicyclopentadiene 75% was therefore considered to be a non-sensitiser to guinea pig skin.

In the supporting study (Litton Bionetics, 1976a), 8 guinea pigs were induced with 10 intracutaneous injections (3/week) of 0.1% dicyclopentadiene (0.05 – 0.1mL). No skin reactions were observed. Two weeks after the last dose, the animals were challenged by injection with 0.05mL of 0.1% dicyclopentadiene and skin reactions graded using the Draize scheme. Mild erythema was seen 24-48 h after administration of this challenge and this was evaluated as a negative response.

Human information

No relevant information


Migrated from Short description of key information:
Dicyclopentadiene is considered not to be a skin sensitiser.

Respiratory sensitisation

Endpoint conclusion
Endpoint conclusion:
no adverse effect observed (not sensitising)
Additional information:

Non human information

There are no specific animal studies to assess respiratory sensitisation but a wide range of inhalation studies in a number of animal species have shown no evidence of respiratory sensitisation potential.

Human information

Very little information has been reported on the irritation effects of dicyclopentadiene in humans. However, in a study in volunteers to determine the human sensory response to dicyclopentadiene vapour and to determine the odour threshold (Kinkead et al, 1971) there was no evidence of respiratory sensitisation.


Migrated from Short description of key information:
There are no specific animal studies to assess respiratory sensitisation but there is no evidence of respiratory sensitisation from the existing animal and human studies with dicyclopentadiene.

Justification for classification or non-classification

Dicyclopentadiene was shown to be non-sensitising in a guideline skin sensitisation study in animals and therefore requires no classification under CLP.

Since there is no evidence for respiratory sensitisation in a range of inhalation studies in various animal species or in the limited documented human exposures, dicyclopentadiene is considered not to warrant classification under CLP.