Dichloro(diphenyl)silane

Endpoint summary

Key value for chemical safety assessment

Effects on fertility

Description of key information

 In accordance with Column 1 of REACH Annex IX the extended one-generation reproductive toxicity study (required in Section 8.7.3) does not need to be conducted if no adverse effects on reproductive organs were observed in a 90-day repeated dose toxicity study. A 90-day repeated dose oral toxicity study in rats is ongoing with the registration substance dichloro(diphenyl)silane (CAS 80-10-4). Therefore, the need for further testing for reproductive toxicity will be assessed once the results of the OECD 408 are available.

Link to relevant study records

Reference

Endpoint:

extended one-generation reproductive toxicity - basic test design (Cohorts 1A, and 1B without extension)

Data waiving:

study scientifically not necessary / other information available

Justification for data waiving:

other:

Reason / purpose for cross-reference:

data waiving: supporting information

Reason / purpose for cross-reference:

data waiving: supporting information

Effect on fertility: via oral route

Endpoint conclusion:

no study available

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 accordance with Column 1 of REACH Annex IX the extended one-generation reproductive toxicity study (required in Section 8.7.3) does not need to be conducted if no adverse effects on reproductive organs were observed in a 90-day repeated dose toxicity study. A 90-day repeated dose oral toxicity study in rats is ongoing with the registration substance dichloro(diphenyl)silane (CAS 80-10-4). Therefore, the need for further testing for reproductive toxicity will be assessed once the results of the OECD 408 are available.

Effects on developmental toxicity

Description of key information

According to ECHA decision number TPE-D-2114425282-58-01/F, there is an ongoing pre-natal developmental toxicity study with the registration substance, conducted according to OECD TG 414 and in compliance with GLP. The study will be submitted as soon as possible once the final report is available.

Link to relevant study records

Reference

Endpoint:

developmental toxicity

Data waiving:

other justification

Justification for data waiving:

other:

Qualifier:

according to guideline

Guideline:

OECD Guideline 414 (Prenatal Developmental Toxicity Study)

Version / remarks:

25 June 2018

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Limit test:

yes

Species:

rat

Strain:

Wistar

Remarks:

Crl: WI(Han)

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River, 97633 Sulzfeld, Germany
- Age at study initiation: approx. 11-12 weeks old for females; between 12 weeks and not older than 24 weeks for males
- Weight at study initiation:
- Housing: Housed individually in IVC cages on saw fibre bedding (except during the pre-mating period when females will be kept in groups of two animals and during mating period when two females will be paired with one male)
- Diet: Altromin 1324 maintenance diet for rats and mice provided ad libitum
- Water: Tap water, sulphur acidified to a pH of approximately 2.8 provided ad libitum
- Acclimation period: At least 5 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22 ± 3
- Humidity (%): 55 ± 10
- Air changes (per hr): 10
- Photoperiod (hrs dark / hrs light): 12 hours light, 12 hours dark

Route of administration:

oral: gavage

Vehicle:

corn oil

Details on exposure:

PREPARATION OF DOSING SOLUTIONS:
The test item was weighed into a tared plastic vial and the vehicle was added to give the appropriate final concentration of the test item. The formulation was vortexed and/or stirred until visual homogeneity was achieved. Formulates were constantly stirred until daily administration. The test item formulation were prepared freshly on each administration day before the administration procedure and administered directly after its preparation. The vehicle was used as control item.


VEHICLE
- Justification for use and choice of vehicle:
The vehicle was selected in consultation with the sponsor based on the test item’s characteristics.

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

Before beginning of the treatment period, formulation samples were prepared and analysed in order to obtain knowledge about stability and homogeneity of the test item.

Details on mating procedure:

- Impregnation procedure: cohoused
- If cohoused:
- M/F ratio per cage: 1:2
- Length of cohabitation: Females were paired for cohabitation in batches in order to control the number of animals for terminal sacrifice on a particular day. After getting 92 sperm positive females, the remaining females and males will be discarded without any observations.
- Verification of same strain and source of both sexes: yes
- Proof of pregnancy: sperm in vaginal smear referred to as day 0 of pregnancy

Duration of treatment / exposure:

From gestation day (GD) 5 until GD 19

Frequency of treatment:

7 days per week

Duration of test:

From GD 5 until GD 20

Dose / conc.:

50 mg/kg bw/day (actual dose received)

Dose / conc.:

100 mg/kg bw/day (actual dose received)

Dose / conc.:

200 mg/kg bw/day (actual dose received)

No. of animals per sex per dose:

20 pregnant females per group

Control animals:

yes, concurrent vehicle

Details on study design:

- Dose selection rationale: On the basis of a 14-day dose range finding study with dichloro(diphenyl)silane (CAS RN 80-10-4) in male and female Wistar rats with dose levels of 25, 50, 100, 500 and 375 mg/kg bw/day the following conclusions can be made: Mortality occurred in 2/2 males and 2/2 females at the dose of 500 mg/kg bw/day and 1/2 females at 375 mg/kg bw/day. Inflammatory lesions in stomach, small and large intestine were considered as the cause of morbidity. Adverse clinical signs were observed at 500 mg/kg bw/day in both males and females including, increased salivation (slight), apathy, hypotonia (muscle), reduced spontaneous activity (slight/severe), slow movements, piloerection (moderate) and half eyelid close (both), hypothermia, lacrimation (left) on treatment days. No treatment-related mortality or marked clinical signs were observed at up to 100 mg/kg bw/day. Treatment did not affect the body weight gain at up to 100 mg/kg bw/day in males and females and body weight was comparable to the respective controls. Test item-related gross lesions were noted in the stomach, small and large intestine at ≥375 mg/kg bw/day and these were evident during the histopathological examination. The test item caused inflammatory and degenerative findings in the stomach of animals at 375 and 500 mg/kg bw/day. Based on the histopathological data, the NOAEL was established at 100 mg/kg bw/day.
- Rationale for animal assignment (if not random): Females were assigned to the experimental groups with achieving a most homogenous variation in body weight throughout the groups (randomisation will be performed with IDBS Workbook 10.1.2 software).

Maternal examinations:

CAGE SIDE OBSERVATIONS: Yes
- Time schedule: General clinical observations were made at least once a day, preferably at the same time each day. Twice daily all animals were observed for morbidity and mortality except on weekends and public holidays when observations were made once daily.
- Clinical observations included spontaneous activity, lethargy, recumbent position, convulsions, tremors, apnoea, asphyxia, vocalisation, diarrhoea, changes in the skin and fur, eyes and mucous membranes (salivation, discharge), piloerection and pupil size. Changes in gait, posture, response to handling as well as the presence of clonic or tonic movements, stereotypes, or bizarre behaviour were recorded.

DETAILED CLINICAL OBSERVATIONS: Yes
- Time schedule: At least once a day

BODY WEIGHT: Yes
- Time schedule for examinations: All animals were weighed once before initiation of pairing to ensure that the body weights were within ± 20 % variation. The sperm positive females were weighed on GD 0, 5, 8, 11, 14, 17 and 20. Males were not be weighed in this study except once before initiation of pairing.

FOOD CONSUMPTION (if feeding study): Yes
- Food consumption for each animal determined and mean daily diet consumption calculated as g food/kg body weight/day: Yes

POST-MORTEM EXAMINATIONS: Yes
- Sacrifice on gestation day # 20
- Organs examined: See table 1

OTHER: Thyroid hormones levels from samples from all dams were assessed at the end of the treatment prior to or as part of the sacrifice of the animals. At termination, blood samples were collected from the defined site will be collected in serum separator tubes and obtained serum were stored at ≤-20°C. Serum samples were assessed for serum levels for thyroid hormones (T3, T4, TSH) using ELISA.

Ovaries and uterine content:

The ovaries and uterine content was examined after termination: Yes
Examinations included:
- Gravid uterus weight: Yes
- Number of corpora lutea: Yes
- Number of implantations: Yes
- Number of early resorptions: Yes
- Number of late resorptions: Yes

Fetal examinations:

- External examinations: Yes: all per litter
- Soft tissue examinations: Yes: half per litter
- Skeletal examinations: Yes: half per litter
- Head examinations: Yes: half per litter

Statistics:

A statistical assessment of the results of the body weight and food consumption will be performed by comparing values of dosed animals with control animals using a one-way ANOVA and a post-hoc Dunnett Test. Results of absolute and relative organ weights, thyroid hormones and foetal evaluation parameters like external, visceral, craniofacial and skeletal parameters will be statistically analysed by comparing values of dosed with control animals using either a parametric one-way ANOVA and a post-hoc Dunnett Test or a non-parametric Kruskal-Wallis Test and a post-hoc Dunn’s Test, based on the results of homogeneity and normality tests. The statistics will be performed with GraphPad Prism V.6.01 software or Ascentos 1.3.4 software (p<0.05 is considered as statistically significant).

Effect on developmental toxicity: via oral route

Endpoint conclusion:

no study available (further information necessary)

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

According to ECHA decision number TPE-D-2114425282-58-01/F, there is an ongoing pre-natal developmental toxicity study with the registration substance, conducted according to OECD TG 414 and in compliance with GLP. The study will be submitted as soon as possible once the final report is available.

Justification for classification or non-classification

In the absence of appropriate measured data, the substance is not classified for reproductive or developmental toxicity.