Phosphonic acid, P-(3-silylpropyl)-, Si,Si,Si-tris(mixed ethoxy and methoxy) derivs., mixed Et and Me diesters

Endpoint summary

Description of key information

In vitro skin irritation tests (BASF, 2015): not irritating
In vitro eye irritation tests (BASF, 2015): irritating

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:

adverse effect observed (irritating)

Respiratory irritation

Endpoint conclusion

Endpoint conclusion:

no study available

Additional information

In vitro skin irritation:

The objective was to assess the potential for corrosive activity and skin irritation of Diethylphosphonatopropyltrimethoxysilan. Using the currently available methods a single in vitro assay may not always be sufficient to cover the full range of skin irritating/corrosion potential. Therefore, two in vitro assays were part of this in vitro skin irritation and corrosion test strategy: The Skin Corrosion Test (SCT) and Skin Irritation Test (SIT). The potential of Diethylphosphonatopropyltrimethoxysilan to cause dermal corrosion/irritation was assessed by a single topical application of 50 μL (corrosion test) or 30 μL (irritation test) of the undiluted test substance to a reconstructed three dimensional human epidermis model (EpiDerm™). For the corrosion test two EpiDerm™ tissue samples were incubated with the test substance for 3 minutes and 1 hour, respectively. The irritation test was performed with three EpiDerm™ tissue samples, which were incubated with the test substance for 1 hour followed by a 42-hours post-incubation period. Tissue destruction was determined by measuring the metabolic activity of the tissue after exposure/post-incubation using a colorimetric test. The reduction of mitochondrial dehydrogenase activity, measured by reduced formazan production after incubation with a tetrazolium salt (MTT) was chosen as endpoint. The formazan production of the testsubstance treated epidermal tissues is compared to that of negative control tissues. The quotient of the values indicates the relative tissue viability. The EpiDerm™ skin corrosion/irritation test showed the following results: The test substance is not able to reduce MTT directly. Corrosion test: The mean viability of the test-substance treated tissues determined after an exposure period of 3 minutes was 93.4%, and it was 96.1% after an exposure period of 1 hour. Irritation test: The mean viability of the test-substance treated tissues determined after an exposure period of 1 hour with about 42 hours post-incubation was 100.4%. Based on the observed results and applying the evaluation criteria it was concluded, that Diethylphosphonatopropyltrimethoxysilan does not show a skin irritation potential in the EpiDerm™ in vitro skin irritation and corrosion test strategy under the test conditions chosen.

In vitro eye irritation:

The objective of the present study was the determination of a possible eye irritating potential of Diethylphosphonatopropyltrimethoxysilan. Using the currently available methods a single in vitro assay may not always be sufficient to cover the full range of eye irritating potential. Therefore, two in vitro assays were part of this in vitro eye irritation test strategy: The Bovine Corneal Opacity and Permeability Test (BCOP Test) and EpiOcular Eye Irritation Test.

BCOP

The potential of Diethylphosphonatopropyltrimethoxysilan to cause ocular irritation or serious damage to the eyes was assessed by a single topical application of 750 μL of the undiluted test substance to the epithelial surface of isolated bovine corneas. Three corneas were treated with the test substance for 10 minutes followed by a 2-hours post-incubation period. In addition to the test substance a negative control (NC; de-ionized water) and a positive control (PC; 100% ethanol) were applied to three corneas each. Corneal opacity was measured quantitatively as the amount of light transmitted through the cornea. Permeability was measured quantitatively as the amount of sodium fluorescein dye that passes across the full thickness of the cornea. Both measurements were used to calculate an In Vitro Irritancy Score of the test substance. The mean In Vitro Irritancy Score (IVIS) of the test substance was 16.2 (negative control: 2.0, positive control: 55.8). Thus the test substance was not identified as corrosive or severe irritant.

EpiOcular

The potential of Diethylphosphonatopropyltrimethoxysilan to cause ocular irritation was assessed by a single topical application of 50 μL of the undiluted test substance to a reconstructed three dimensional human cornea model (EpiOcular™). Two EpiOcular™ tissue samples were incubated with the test substance for 30 minutes followed by a 2-hours post-incubation period. Tissue destruction was determined by measuring the metabolic activity of the tissue after exposure/post-incubation using a colorimetric test. The reduction of mitochondrial dehydrogenase activity, measured by reduced formazan production after incubation with a tetrazolium salt (MTT) was chosen as endpoint. The formazan production of the testsubstance treated epidermal tissues is compared to that of negative control tissues. The ratio of the values indicates the relative tissue viability. The EpiOcular™ eye irritation test showed the following results: The test substance is not able to reduce MTT directly. The mean viability of the test-substance treated tissues was 53.7%. Thus, based on this result, the test substance was identified as irritant.

Based on the results for BCOP and EpiOcular Test and applying the evaluation criteria, Diethylphosphonatopropyltrimethoxysilan shows an eye irritation potential in the in vitro eye irritation test strategy under the test conditions chosen.

Effects on eye irritation: irritating

Justification for classification or non-classification

Based on the available data, the substance is not irritating to the skin according to DSD-DPD and CLP but has to be classified as irritating to the eye (R36/Cat. 2) according to DSD-DPD and CLP.