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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.

The new ECHA CHEM database has been released by ECHA, and it now contains all REACH registration data. There are more details on the transition of ECHA's published data to ECHA CHEM here.

Diss Factsheets

Administrative data

Key value for chemical safety assessment

Effects on fertility

Effect on fertility: via oral route
Endpoint conclusion:
adverse effect observed
Dose descriptor:
NOAEL
1 000 mg/kg bw/day
Study duration:
subchronic
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

No data on the reproductive toxicity of potassium methylsilanetriolate are available, so good quality data for the surrogate substance trimethoxy(methyl)silane (CAS 1185-55-3) have been used to assess the reproductive toxicity of tripotassium propylsilanetriolate. An in vitro cytogenicity assay (OECD 473) is being conducted with potassium methylsilanetriolate. When the results of this test are available, depending on the outcome of the study, read across from trimethoxy(methyl)silane may be reconsidered.

Refer to the repeated dose toxicity endpoint summary (Section 7.5 of the IUCLID) for further details on read-across justification.

Oral administration of read-across substance trimethoxy(methyl)silane to male and female Sprague-Dawley rats at doses of 50, 250 or 1000 mg/kg/day did not result on any effects on reproductive parameters and the No-observed-Adverse-Effect-Level for reproductive performance was considered to be 1000 mg/kg/day.

The substance is classified as corrosive (Cat 1A) so extended one-generation reproductive toxicity testing with the substance itself would have to be performed at a very low, non-irritant/corrosive doses, where no relevant systemic toxicity is expected. An extended one-generation reproductive toxicity study will be conducted with the surrogate substance trimethoxy(methyl)silane (CAS 1185-55-3) when a final decision has been received from ECHA (Draft Decision SEV-D-2114279311-53-01/D).

Short description of key information:
No data on the reproductive toxicity of potassium methylsilanetriolate are available, therefore data on trimethoxy(methyl)silane (MTMS) have been read-across. Exposure to trimethoxy(methyl)silane was not associated with reproductive toxicity. The findings support a NOAEL of at least 1000 mg/kg bw/day.

Justification for selection of Effect on fertility via oral route:
The study was carried out in accordance with an appropriate OECD test guideline and in compliance with GLP.

Effects on developmental toxicity

Description of key information
No data on the developmental toxicity of potassium methylsilanetriolate are available, therefore data on trimethoxy(methyl)silane have been read-across.  The findings support a NOAEL of at least 1000 mg/kg bw/day.
Effect on developmental toxicity: via oral route
Endpoint conclusion:
adverse effect observed
Dose descriptor:
NOAEL
1 000 mg/kg bw/day
Study duration:
subchronic
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

No data on the developmental toxicity of potassium methylsilanetriolate are available. Potassium methylsilanetriolate is a mono-constituent ionic substance of 35-55% w/w potassium methylsilanetriolate in aqueous solution that has a very alkaline pH of >12. Potassium methylsilanetriolate dissociates complete into potassium and methylsilanetriolate ions in aqueous solution.

Due to the high pH, the substance is classified as corrosive (Cat 1A), so developmental toxicity testing with the substance itself would have to be performed at a very low, non-irritant/corrosive doses, where no relevant systemic toxicity is expected.

In more dilute aqueous solution the pH of the substance will be reduced dependent on concentration. As the pH is reduced, the concentration of the non-ionised form of methylsilanetriolate (methylsilanetriol) increases. At pH <9.0, the substance is no longer in the ionised form; methylsilanetriol is the predominant species at low concentrations, with dimers and oligomers of methylsilanetriol forming at higher concentrations. Under comparable conditions of concentration and pH, methylsilanetriolate is equivalent to methylsilanetriol.

The surrogate substance, trimethoxy(methyl) silane (MTMS), hydrolyses in contact with water (half-life ca. 2 hours at pH 7), producing methanol and methylsilanetriol. Under acidic conditions, such as in the stomach following oral ingestion, hydrolysis is very rapid (half-life estimated as approximately 5 seconds at pH 2 and 37°C).

Since potassium ions will not contribute to any systemic toxicity effect, and methanol does not contribute any significant repeated dose toxicity to rodents at the dose levels tested, it is considered appropriate to read across the available data on MTMS. An in vitro cytogenicity assay (OECD 473) is being conducted with potassium methylsilanetriolate. When the results of this test are available, depending on the outcome of the study, read across from trimethoxy(methyl)silane may be reconsidered.

The key study was read across from the structurally analogous substance trimethoxy(methyl)silane (CAS 1185-55-3).

The key study for developmental toxicity from the read across substance is the only study available for this endpoint. It is a reliable OECD 422 Combined Repeat Dose Toxicity and Screening Study for Reproductive and Developmental Toxicity, carried out in compliance with GLP (Dow Corning Corporation, 2005). No gross abnormalities were found for any of the pups, with the exception of a single runt in the 50 mg/kg/day group. No other effects were reported. The study was carried out in accordance with an appropriate OECD test guideline and in compliance with GLP. The original study was considered reliability 1. Read-across to the registered substance is considered scientifically justified and is reliability 2.

Additional information on read across approach is given in a supporting report (PFA, 2015t) attached in Section 13 of the IUCLID 5 dossier.

A full developmental toxicity study will be conducted with the surrogate substance trimethoxy(methyl)silane (CAS 1185-55-3) when a final decision has been received from ECHA (Draft Decision SEV-D-2114279311-53-01/D).

PFA, (2015t). Peter Fisk Associates, Analogue report – mammalian toxicity of alkyl alkoxysilanes, PFA.404.002.002.


Justification for selection of Effect on developmental toxicity: via oral route:
The study was carried out in accordance with an appropriate OECD test guideline and in compliance with GLP.

Justification for classification or non-classification

Based on the available read-across data, potassium methylsilanetriolate does not require classification for reproductive or developmental toxicity according to Regulation (EC) No. 1272/2008.

Additional information