Diethyl phenylphosphonite

Endpoint summary

Key value for chemical safety assessment

Genetic toxicity in vitro

Description of key information

Ames test: neg. (GLP, OECD 471, BASF 2011)

Link to relevant study records

Reference

Endpoint:

in vitro gene mutation study in bacteria

Remarks:

Type of genotoxicity: gene mutation

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2010-12-21 to 2011-01-27

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP and guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 471 (Bacterial Reverse Mutation Assay)

Version / remarks:

1997-07-21

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method B.13/14 (Mutagenicity - Reverse Mutation Test Using Bacteria)

Version / remarks:

2008-05-30

Deviations:

no

Qualifier:

according to guideline

Guideline:

EPA OPPTS 870.5100 - Bacterial Reverse Mutation Test (August 1998)

Version / remarks:

adopted Aug 1998

GLP compliance:

yes (incl. QA statement)

Type of assay:

bacterial reverse mutation assay

Species / strain / cell type:

S. typhimurium TA 1535, TA 1537, TA 98, TA 100 and E. coli WP2

Metabolic activation:

with and without

Metabolic activation system:

liver S9 mix from induced rats

Test concentrations with justification for top dose:

33 ug, 100 ug, 333 ug, 1000 ug, 2650 ug, 5300 ug/plate (standard plate test)
33 ug, 100 ug, 333 ug, 1000 ug, 2650 ug, 5300 ug/plate (preincubation test)

Vehicle / solvent:

- Vehicle(s)/solvent(s) used: DMSO
- Justification for choice of solvent/vehicle: Due to the limited solubility of the test substance in water, DMSO was used as vehicle, which had been demonstrated to be suitable in bacterial reverse mutation tests and for which historical control data are available.

Untreated negative controls:

no

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

other: with metabolic activation: 2-aminoanthracene; without metabolic activation: N-methyl-N'-nitro-N-nitrosoguanidine, 4-nitro-o-phenylenediamine, 9-aminoacridine and 4-nitroquinoline-N-oxide

Details on test system and experimental conditions:

METHOD OF APPLICATION: in agar (plate incorporation) and preincubation

DURATION
-Preincubation period: 20 min, 37 °C
- Exposure duration:48-72 hours, 37 °C

NUMBER OF REPLICATIONS:3

DETERMINATION OF CYTOTOXICITY
- Method: relative total growth

Evaluation criteria:

The test substance is considered positive in this assay if the following criteria are met:
A dose-related and reproducible increase in the number of revertant colonies, i.e. about doubling of the spontaneous mutation rate in at least one tester strain either without S9 mix or after adding a metabolizing system.
A test substance is generally considered non-mutagenic in this test if:
The number of revertants for all tester strains were within the historical negative control range under all experimental conditions in at least two experiments carried out independently of each other.

Species / strain:

S. typhimurium TA 1535, TA 1537, TA 98, TA 100 and E. coli WP2

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

other: bacteriotoxic effect was occasionally observed depending on the strain from about 2 650 μg/plate onward

Vehicle controls validity:

valid

Untreated negative controls validity:

not examined

Positive controls validity:

valid

Additional information on results:

TEST-SPECIFIC CONFOUNDING FACTORS
- Precipitation: No test substance precipitation was found with and without S9 mix.

ADDITIONAL INFORMATION ON CYTOTOXICITY:
A bacteriotoxic effect (reduced his- background growth, slight decrease in the number of his+ revertants, reduction in the titer) was occasionally observed in the standard plate test depending on the strain and test conditions from about 2 650 μg/plate onward.
In the preincubation assay bacteriotoxicity (slight decrease in the number of his+ revertants) was occasionally observed depending on the strain and test conditions from about 2 650 μg/plate onward.

Remarks on result:

other: all strains/cell types tested

Remarks:

Migrated from field 'Test system'.

A biologically relevant increase in the number of his+ or trp+ revertants was not observed in the standard plate test or in the preincubation test either without S9 mix or after the addition of a metabolizing system.

Conclusions:

Interpretation of results (migrated information):
negative

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (negative)

Additional information

Additional information from genetic toxicity in vitro:

The test substance Diethoxyphenylphosphin was tested for mutagenicity in the Salmonella typhimurium / Escherichia coli reverse mutation assay both in the standard plate test and in the preincubation test with and without the addition of a metabolizing system (S9 mix) obtained from rat liver using the Salmonella strains TA 1535, TA 100, TA 1537, TA 98 and Escherichia coli WP2 uvrA.

The test substance did not lead to a biologically relevant increase in the number of revertant colonies either without S9 mix or after adding a metabolizing system in two experiments carried out independently of each other (standard plate test and preincubation assay). Besides, the results of the negative as well as the positive controls performed in parallel corroborated the validity of this study, since the values fulfilled the acceptance criteria of this study. In this study with and without S9 mix, the number of revertant colonies in the negative controls was within the range of the historical negative control data for each tester strain. In addition, the positive control substances both with and without S9 mix induced a significant increase in the number of revertant colonies within the range of the historical positive control data or above.

Justification for selection of genetic toxicity endpoint
only one reliable GLP and guideline study available

Justification for classification or non-classification

Under the experimental conditions of the study, the test substance Diethoxyphenylphosphin is not mutagenic in the Salmonella typhimurium/Escherichia coli reverse mutation assay in the absence and the presence of metabolic activation and therefore no subject to classification according to Directive 67/548/EEC (DSD) and accoding to Regulation (EC) No 1272/2008 (CLP).