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Toxicological information

Genetic toxicity: in vitro

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Administrative data

Endpoint:
in vitro gene mutation study in bacteria
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2017
Report date:
2018

Materials and methods

Test guideline
Qualifier:
according to guideline
Guideline:
OECD Guideline 471 (Bacterial Reverse Mutation Assay)
GLP compliance:
yes (incl. QA statement)
Type of assay:
bacterial reverse mutation assay

Test material

Constituent 1
Chemical structure
Reference substance name:
Diethyl ethylphosphonate
EC Number:
201-111-9
EC Name:
Diethyl ethylphosphonate
Cas Number:
78-38-6
Molecular formula:
C6H15O3P
IUPAC Name:
diethyl ethylphosphonate
Test material form:
liquid
Specific details on test material used for the study:
Name: Diethyl ethylphosphonate
CAS number 78-38-6
Batch n°: 170623
Manufacturing date: 12/06/2017
Expiration date: 11/06/2019
Receiving date: 23/08/2017
Chelab ID: 17.076968.0001
Composition as reported in the certificate provided by the sponsor (see annex n°1 to the study plan): Diethyl ethylphosphonate 99.54%.

Method

Target gene:
Salmonella typhimurium TA98
NIP 877
Salmonella typhimurium TA100
NIP 876
Salmonella typhimurium TA1535
NIP 878
Salmonella typhimurium TA1537
NIP 879
Escherichia coli WP2 uvrA pKM101
NIP 880
Species / strain
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:
S9 mix
Test concentrations with justification for top dose:
0.05 μl/plate. 0.16 μl/plate, 0.5 μl/plate, 1.58 μl/plate, 5 μl/plate
Vehicle / solvent:
ddH2O was used as solvent to dissolve the test substance.
Controls
Untreated negative controls:
yes
Remarks:
ddH2O and DMSO were used
Positive controls:
yes
Positive control substance:
benzo(a)pyrene
other: 2-aminoantracene
Details on test system and experimental conditions:
In this study the plate incorporation method was applied. The study was divided into 2 main phases:
1) Preliminary cytotoxicity to determine whether the test item was cytotoxic or not, in presence and absence of metabolic activation system (S9 mix). For this preliminary phase, Salmonella typhimurium TA100, one of the 5 strains that are employed in the test, was exposed to 5 concentrations of the test substance, in the presence and in the absence of an exogenous metabolic activation system (S9 mix). The survival of treated cultures was determined by verifying the presence of a normal bacterial background. Absent or abnormal background was indicative of a cytotoxic response.
2) Ames test. For the plate incorporation method, suspensions of 5 different bacteria strains were exposed to 5 concentrations of the test substance in the presence and in the absence of an exogenous metabolic activation system (S9 mix).
The suspensions were then immediately mixed with an overlay agar and plated onto minimal medium. After two days of incubation at 37°C, revertant colonies were compared to the number of spontaneous revertant colonies on solvent control plates.
Evaluation criteria:
Positive results from the bacterial reverse mutation test indicate that a substance induces point mutations by base substitutions or frameshifts in the genome of either Salmonella typhimurium and/or Escherichia coli.
Negative results indicate that under the test conditions, the test substance is not mutagenic in the tested species.
On the basis of the results obtained, it can be concluded that, under the test conditions applied, the test item “Diethyl ethylphosphonate”, batch n° 170623, is considered not mutagenic.
However, in accordance with OECD 471:1997, whereas there is no requirement for verification of a clear positive response, negative results need to be confirmed by other means on a case by case basis, in agreement with the sponsor.

Results and discussion

Test resultsopen allclose all
Species / strain:
S. typhimurium TA 100
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
no cytotoxicity
Vehicle controls validity:
valid
Untreated negative controls validity:
valid
Positive controls validity:
valid
Species / strain:
S. typhimurium TA 1535
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
no cytotoxicity
Vehicle controls validity:
valid
Untreated negative controls validity:
valid
Positive controls validity:
valid
Species / strain:
S. typhimurium TA 1537
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
no cytotoxicity
Vehicle controls validity:
valid
Untreated negative controls validity:
valid
Positive controls validity:
valid
Species / strain:
S. typhimurium TA 98
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
no cytotoxicity
Vehicle controls validity:
valid
Untreated negative controls validity:
valid
Positive controls validity:
valid
Species / strain:
E. coli WP2 uvr A pKM 101
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
no cytotoxicity
Vehicle controls validity:
valid
Untreated negative controls validity:
valid
Positive controls validity:
valid

Applicant's summary and conclusion