1,1,1,3,5,5,5-heptamethyl-3-octyltrisiloxane

Endpoint summary

Description of key information

In the key skin irritation study, conducted according to OECD TG 404, and in compliance with GLP, the test substance, 1,1,1,3,5,5,5-heptamethyl-3-octyltrisiloxane, was reported to be not irritating to rabbit skin (Aventis, 2001).

In the key in vitro eye irritation study, conducted according to OECD TG 437, and in compliance with GLP, the test substance, 1,1,1,3,5,5,5-heptamethyl-3-octyltrisiloxane, was reported to be not irritating to corneas and the reported in vitro irritation score was 0.35 (Eurofins, 2016).

Key value for chemical safety assessment

Skin irritation / corrosion

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not irritating)

Eye irritation

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not irritating)

Respiratory irritation

Endpoint conclusion

Endpoint conclusion:

no study available

Additional information

In the key skin irritation study, conducted according to OECD TG 404, and in compliance with GLP, the test substance, 1,1,1,3,5,5,5-heptamethyl-3-octyltrisiloxane, was reported to be not irritating to rabbit skin (Aventis, 2001).

Following application of 0.5 mL of undiluted test substance onto the skin of 3 female rabbits, kept in contact with the skin under semiocclusive dressing for 4 hours, no erythema or oedema were observed in any of the test animals at 1, 24, 48 and 72 hours post-application. No signs of systemic toxicity were noted in any of the animals.

A supporting skin irritation study was available, which also concluded the test item to be not irritating to rabbit skin (BRRC, 1995).

In the key in vitro eye irritation study, conducted according to OECD TG 437, and in compliance with GLP, the test substance, 1,1,1,3,5,5,5-heptamethyl-3-octyltrisiloxane, was reported to be not irritating to corneas and the reported in vitro irritation score was 0.35 (< 3) (Eurofins, 2016).

Corneas were excised from eyes collected as a by-product from slaughtered animals. 0.750 µL of undiluted test material was applied to 3 test corneas and incubated for 10 min at 32 +/- 1°C. Following incubation, the corneas were washed three times with MEM to remove residual test material and incubated with RPMI for 2 hours at 32 +/- 1°C, then illuminance measurement was performed. After the measurement, sodium fluorescein solution was added and the corneas were incubated for 90 min at 32 +/- 1°C. The opacity density was determined using a spectrophotometer and the in vitro irritation score was calculated. Negative and positive controls were included and gave the expected results.

Two supporting eye irritation studies were also available, which concluded the test item to be not irritating to rabbit eyes and supported the conclusion from the key study (Aventis, 2001; BRRC, 1995). Both studies were conducted according to an appropriate OECD test guideline or to a protocol similar to it, and in compliance with GLP.

Following 24-hour instillation of 0.1 mL of undiluted test item into the lower lid of 3 female rabbits, conjunctival redness in 2 of the animals as well as colourless eye discharge with moistening of the lids in all of the test animals were observed within 1 hour after administration. All signs of irritation disappeared within 24 hours post-treatment. The treated eyes were washed thoroughly with isotonic saline at 37°C at 24 hours post-instillation. Observations were performed at 1, 24, 48 and 72 hours after treatment (Aventis, 2001).

Following a single instillation of undiluted test material into the eyes of 3 female and 3 male rabbits, minor conjunctival redness with a minor to moderate ocular discharge were evident in all of the test animals. Ocular irritation subsided within 24 hours in 5 animals and 48 hours in 1 animal (BRRC, 1995).

Justification for classification or non-classification

Based on the available data for 1,1,1,3,5,5,5-heptamethyl-3-octyltrisiloxane, no classification is required for skin and eye irritation according to Regulation (EC) No. 1272/2008.