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

Endpoint summary

Key value for chemical safety assessment

Effects on fertility

Description of key information

In the combined 28-day repeated dose toxicity study with the reproduction/ developmental toxicity screening test, the reported NOAEL for reproductive toxicity was greater than 1000 mg/kg bw. No treatment-related changes were observed in any of the test animals.

Effect on fertility: via oral route

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

NOAEL

1 000 mg/kg bw/day

Study duration:

subacute

Species:

rat

Effect on fertility: via inhalation route

Endpoint conclusion:

no study available

Effect on fertility: via dermal route

Endpoint conclusion:

no study available

Additional information

In the combined 28-day repeated dose toxicity study with the reproduction/ developmental toxicity screening test, 1,1,1,3,5,5,5-heptamethyl-3-octyltrisiloxane was tested according to OECD TG 422 and in compliance with GLP (Charles River, 2016).

The test item,1,1,1,3,5,5,5-heptamethyl-3-octyltrisiloxane, was formulated in dried and deacidified corn oil and administered orally (gavage) to 10 male and 10 female rats per group. An extra 5 animals per sex in the control and high dose group were included and allowed 14 days of recovery. All the animals were treated daily, for at least 28 days. Main males and recovery males were exposed to the test substance for 29 days. Main females were treated for 41 to 47 days. Recovery females were exposed for 43 days. The selected doses were 100, 300 and 1000 mg/kg bw/day, based on toxicity results from a 14-day dose range-finding study.

The following observations and examinations were evaluated: mortality / viability, clinical signs (daily), functional observations and locomotor activity (end of treatment), body weight and food consumption (at least at weekly intervals), clinical pathology (end of treatment), macroscopy at termination, organ weights and histopathology on a selection of tissues. In addition, the following reproduction/developmental parameters were determined: mating, fertility and conception indices, precoital time, number of corpora lutea and implantation sites, gestation index and duration, parturition, maternal care, sex ratio and early postnatal pup development (mortality, clinical signs, body weights, sex and macroscopy). Formulations were analysed once during the study to assess accuracy and homogeneity.

No treatment-related effects on systemic toxicity or reproductive parameters were observed in any of the test animals and it was concluded that the NOAEL for parental toxicity and reproductive effects was greater than 1000 mg/kg bw.

Effects on developmental toxicity

Description of key information

In the combined 28-day repeated dose toxicity study with the reproduction/ developmental toxicity screening test, the reported NOAEL for maternal toxicity and developmental/ teratogenic effects was greater than 1000 mg/kg bw. No treatment-related changes were observed in any of the test animals.

Effect on developmental toxicity: via oral route

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

NOAEL

1 000 mg/kg bw/day

Study duration:

subacute

Species:

rat

Effect on developmental toxicity: via inhalation route

Endpoint conclusion:

no study available

Effect on developmental toxicity: via dermal route

Endpoint conclusion:

no study available

Additional information

In the combined 28-day repeated dose toxicity study with the reproduction/ developmental toxicity screening test,1,1,1,3,5,5,5-heptamethyl-3-octyltrisiloxane was tested according to OECD TG 422 and in compliance with GLP (Charles River, 2016).

The test item,1,1,1,3,5,5,5-heptamethyl-3-octyltrisiloxane, was formulated in dried and deacidified corn oil and administered orally (gavage) to 10 male and 10 female rats per group. An extra 5 animals per sex in the control and high dose group were included and allowed 14 days of recovery. All the animals were treated daily, for at least 28 days. Main males and recovery males were exposed to the test substance for 29 days. Main females were treated for 41 to 47 days. Recovery females were exposed for 43 days. The selected doses were 100, 300 and 1000 mg/kg bw/day, based on toxicity results from a 14-day dose range-finding study.

The following observations and examinations were evaluated: mortality / viability, clinical signs (daily), functional observations and locomotor activity (end of treatment), body weight and food consumption (at least at weekly intervals), clinical pathology (end of treatment), macroscopy at termination, organ weights and histopathology on a selection of tissues. In addition, the following reproduction/developmental parameters were determined: mating, fertility and conception indices, precoital time, number of corpora lutea and implantation sites, gestation index and duration, parturition, maternal care, sex ratio and early postnatal pup development (mortality, clinical signs, body weights, sex and macroscopy). Formulations were analysed once during the study to assess accuracy and homogeneity.

No treatment-related effects on development were observed in any of the test animals and it was concluded that the NOAEL for maternal toxicity and developmental effects was greater than 1000 mg/kg bw.

Justification for classification or non-classification

Based on the available data for1,1,1,3,5,5,5-heptamethyl-3-octyltrisiloxane, no classification is required for reproductive or developmental toxicity according to Regulation (EC) No. 1272/2008.