Phosphorous ester

Endpoint summary

Additional information

In vitro mammalian chromosome aberration test

In a mammalian cell cytogenetic assay chromosome aberration was tested (08/625 -020C). The V 79 cells were exposed to GARDO TP 10451 dissolved in DMSO. Two experiments were carried out.

In the first experiment the cells were exposed for 3 hours at 37°C at concentrations of 9.76, 19.53, 39.06 and 78.12 µg/L with and without metabolic activation (S9-mix) and harvested at 20 hours. In the second experiment the exposure period without metabolic activation was 20 hours with concentrations of 4.88, 9.76, 19.53 and 30.06 µg/mL and with metabolic activation at concentrations of 9.76, 19.53, 39.06 and 78.12 for 3 hours. There were no biologically relevant increases in the rate of polyploid or endoreduplicated metaphases in either experiment in the presence or absence of metabolic activation. The validity of the test was shown using Ethylmethane sulphonate and N-Nitrosodimethylamine as positive control.

Therefore GARDO TP 10451 is considered not clastogenic in this system.

The study was conducted according to the OECD Guideline 473 and the EU-Guideline B.10.

Reverse Mutation Assay using Bacteria

In a reverse mutation assay using bacteria (08/625 -007M) five bacterial strains of S. typhimurium (TA 98, TA 100, TA 1535, TA 1537 and E.coli WP uvr A) were exposed to GARDO TP 10451 dissolved in Dimethyl sulfoxide. Two independent experiments, a plate incorporation test and a pre-incubation test, were carried out. Each assay was conducted with and without metabolic activation (S9 -Mix) at concentrations of 5000, 1581.1, 500, 158.1, 50 and 15.81 µg/plate in experiment two 5 µg/plate were investigated too. The highest revertant rate was observed in the first experiment in case of S. typhimurium TA 1535 at 15.81 µg/plate (MF=1.55), without metabolic activation. There wae no additional dose-dependent relationship and these values were below the biological threshold value. The reported data of this mutagenicity assay shows, that under the experimental conditions reported, the test item did not induce gene mutations by frameshift or base-pair substitution in the genome of the strains.

Therefore GARDO TP 10451 is considered non-mutagenic in this bacterial reverse mutation assay.

The study was conducted according to the OECD Guideline 471 and the EU-Guideline B.13/14.

In Vitro Mammalian Cell Gene Mutation Test: Mouse Lymphoma Assay with GARDO TP 10451

An in vitro mammalian cell assay was performed in mouse lymphoma L5178Y TK+/- 3.7.2 C cells at the tk locus to test the potential of GARDO TP 10451 to cause gene mutation and/or chromosome damage. The test item was dissolved in Dimethyl sulfoxide (DMSO) and treatments were carried out for 3 hours with and without metabolic activation (S9) and for 24 hours without metabolic activation. In the first assay the treatments were carried out for 3 hours at concentrations of 1250, 937, 625, 312, 156, 78 and 39 µg/mL in the presence and absence of the S9 -mix. In the second assay the treatments were carried out at the same concentrations for 3 hours in the presence of S9 -mix. And at concentrations of 700, 650, 625, 500, 375, 250, 125 and 75 µg/L for 3 and 24 hours in the absence of S9-mix. The results of assay 1 did not indicate mutagenic effect of GARDO TP 10451 either in the presence or absence of metabolic activation and the defined cytotoxicity levels were not attained in assay 1. In assay 2 no significant positive effect was observed either in the presence or absence of metabolic activation (at the 3 -and 24 -hour treatments) at the evaluated test concentrations. The two assays with GARDO TP 10451 in mouse lymphoma L5178Y TK+/- 3.7.2 C cells were considered valid and met acceptance criteria. Treatments for 3 and 24 hours in the presence and absence of metabolic activation system (S9 -mix) did not result in statistically or biologically significant dose-dependent increase in mutation frequencies.

Therefore no mutagenic effect of GARDO TP 10451 was observed in the mouse lymphoma assay.

The study was conducted according to the OECD Guideline 476 and the EU-Guideline B.17

Short description of key information:
The test substance GARDO TP 10451 was examined an a Chromosome Aberration Test, a Reverse Mutation Assay using Bacteria and a Mouse Lymphoma Assay.
GARDO TP 10451 is considered to be not clastogenic in test system for chromosome aberration, non-mutagenic in a bacterial reverse mutation assay and non-mutagenic and a mouse lymphoma assay.

Endpoint Conclusion:

Justification for classification or non-classification

The results obtained from these studies point to the fact that GARDO TP 10451 is unclassified for gentetic effects according to the CLP/GHS.