Propyltriacetoxysilane

Endpoint summary

Additional information

Read-across from experimental results with supporting substances acetic acid and sodium acetate:

In vitro gene mutation in bacteria: Weight of evidence:

  

In the study by Zeiger et. al., 1992 (reliability 1), bacterial reverse mutation assay (Ames test) according to OECD Guideline 471 and with GLP compliance was performed. A standard Ames test was carried out with acetic acid using Salmonella typhimurium strains TA 98, TA 100, TA 1535, and TA 97, with and without metabolic activation. Acetic acid did not show any mutagenic effect under test conditions. Based on these experimental results, read-across approach was applied and propyltriacetoxysilane was also considered as no mutagenic under test conditions.

 

In the study by McMahon et. al., 1979 (reliability 2), bacterial reverse mutation assay (Ames test) according to OECD Guideline 471 (with deviations) was performed. A bacterial mutagen screening technique was carried out with acetic acid using Salmonella typhimurium strains TA 1535, TA 1537, TA 98 and TA 100, with and without metabolic activation. Acetic acid did not show any mutagenic effect under test conditions. Based on these experimental results, read-across approach was applied and propyltriacetoxysilane was also considered as no mutagenic under test conditions.

 

In the study by Ishidate et. al., 1984 (reliability 2), bacterial reverse mutation assay (Ames test) according to OECD Guideline 471 (with deviations) was performed. The study was carried out with sodium acetate and using Salmonella typhimurium strains TA92, TA1535, TA100, TA1537, TA94, only with metabolic activation. No significant increases in the numbers of revertant colonies were detected at the maximum dose tested. Based on these experimental results, read-across approach was applied and propyltriacetoxysilane was also considered as no mutagenic under test conditions.

 

In vitro mammalian chromosome aberration. Weight of evidence:

 

In the study by Morita et. al., 1990 (reliability 2), a cytogenetic assay was carried out with acetic acid using Chinese hamster ovary K1 cells. Acetic acid was not clastogenic at concentrations close to those showing cytotoxicity, both with and without metabolic activation. Low pH did induce some artificial chromosome aberrations, but these were eliminated by neutralization of the test medium. Based on these experimental results and applying the read-across approach, the substance propyltriacetoxysilane is also considered as not clastogenic under test conditions.

 

In the study by Ishidate et. al., 1983 (reliability 2), a chromosomal aberrations tests were carried out with sodium acetate using a Chinese hamster fibroblast cell line. In the studies, no metabolic activation systems were applied. The maximum dose of each sample was selected by a preliminary test in which the dose needed for 50% cell-growth inhibition was estimated using a cell densiometer. The incidence of cells with aberrations (including gaps) was 0%. Based on these experimental results, the read-across approach was applied and propyltriacetoxysilane was also considered as no mutagenic under test conditions.

In vitro gene mutation in mammalian cells. Experimental results on propyltriacetoxysilane. Key study:

The test item Propyl Triacetoxy Silane PTA was assessed for its potential to induce mutations at the mouse lymphoma thyamidine kinase locus using the cell line L5178Y according to OECD Guideline 476. The Experiment I was performed as a 4h short-term exposure assay up to 10.0 mM (with metabolic activation) and up to 5.5 mM (without metabolic activation). The Experiment II was performed as a 4h short-term exposure up to 8.5 mM (with metabolic activation) and a 24h long-term exposure up to 5.0 mM (without metabolic activation). No biologically relevant increase of mutants was found after treatment with the test item. Additionally, colony sizing showed no clastogenic effects induced by the test item. Therefore, Propyl Triacetoxy Silane (PTA) was considered to be non-mutagenic in the in vitro mammalian cell gene mutation assay (thymidine kinase locus) in mouse lymphoma L5178Y cells with and without metabolic activation under test conditions.

Read-across from experimental results with supporting substance sodium acetate:

In vivo genetic toxicity. Key study:

In the study by Seiler, 1981 (reliability 2), the Testicular DNA-synthesis inhibition test (DSI test) was performed on male mice with Sodium Acetate (single oral dose by gavage). No inhibitory effect on DNA-replication was detectable in animals treated with Sodium Acetate. Based on these results, read-across approach was applied and propyltriacetoxysilane is also considered no genotoxic in animals (based on no effects on DNA-replication).

Justification for selection of genetic toxicity endpoint
No study was selected, since all available studies were negative.

Short description of key information:
In vitro bacteria reverse mutation and in vitro mammalian chromosome aberration: Weight of evidence: Experimental results from studies performed with the supporting substances acetic acid and sodium acetate. All study results were negative. Based on these results, the read-across approaches were applied and propyltriacetoxysilane is considered negative under test conditions.
In vitro gene mutation in mammalian cells: Key study: Propyl Triacetoxy Silane (PTA) was considered to be non-mutagenic in the in vitro mammalian cell gene mutation assay (thymidine kinase locus) in mouse lymphoma L5178Y cells under test conditions.

Endpoint Conclusion: No adverse effect observed (negative)

Justification for classification or non-classification

Based on the available information on genetic toxicity in vitro (Bacterial Reverse Mutation Assay, Chromosome Aberration and Gene Mutation Tests) and in vivo (DNA damage genotoxicity test) the substance propyltriacetoxysilane is considered to be negative, and therefore, the substance is not classified.