3a,4,5,6,7,7a-hexahydro-4,7-methano-1H-indene

Endpoint summary

Key value for chemical safety assessment

Skin sensitisation

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not sensitising)

Additional information:

As detailed in section 5.1.3 of the CSR (IUCLID Section 7.1.1), 3a,4,7,7a-tetrahydro-4,7-methanoindene (DCPD) is considered an appropriate read-across candidate where data are not available for 3a,4,5,6,7,7a-hexahydro-4,7-methano-1H-indene (TCDE).

Non human information

There are no data available for TCDE. Considering the read-across substance, DCPD, the sensitisation potential 75% DCPD 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 75% DCPD 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 DCPD 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% DCPD (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% DCPD 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 human information is available.

Migrated from Short description of key information:
3a,4,5,6,7,7a-hexahydro-4,7-methano-1H-indene (TCDE) is considered not to be a potential 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 DCPD in humans. However, in a study in volunteers to determine the human sensory response to DCPD 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 TCDE or DCPD.

Justification for classification or non-classification

Dicyclopentadiene (DCPD) was shown to be non-sensitising in a guideline skin sensitisation study in animals and therefore requires no classification under DSD or 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, as for the read-across substance DCPD, TCDE is considered not to warrant classification under DSD or CLP.