Diethyl ethylphosphonate

Genetic toxicity: in vitro

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

Test material information

Constituent 1

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 phosphonate

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 results

Test results 1

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

Test results 2

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

Test results 3

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

Test results 4

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

Test results 5

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