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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
Study period:
2017-02-10 - 2017-05-16
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:
2017

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 471 (Bacterial Reverse Mutation Assay)
Version / remarks:
EC Guideline No. 440/2008. Part B: Methods for the Determination of Toxicity and
other health effects, Guideline B.13/14: "Mutagenicity: Reverse Mutation Test using
Bacteria”. Official Journal of the European Union No. L142, 31 May 2008
Deviations:
yes
Remarks:
Due to a calculation error not the correct composition of the S9-mix was prepared; this deviation in the composition of the S9-mix had no effect on the results of the study.
GLP compliance:
yes
Type of assay:
bacterial reverse mutation assay

Test material

Reference
Name:
Unnamed
Type:
Constituent
Test material form:
not specified

Method

Species / strainopen allclose all
Species / strain / cell type:
S. typhimurium TA 1535, TA 1537, TA 98 and TA 100
Species / strain / cell type:
E. coli WP2 uvr A
Metabolic activation:
with and without
Metabolic activation system:
Rat liver microsomal enzymes (S9 homogenate)
Test concentrations with justification for top dose:
Dose-range finding test: Eight concentrations, 1.7, 5.4, 17, 52, 164, 512, 1600 and 5000 μg/plate were tested in triplicate
Since the test item was cytotoxic in the dose range finding test/first mutation experiment, an additional dose range finding test was performed with the tester strains TA100 and WP2uvrA, both with and without S9-mix according to the pre-incubation method. Seven concentrations, 1.7, 5.4, 17, 52, 164, 512 and 1600 μg/plate and 5.4, 17, 52, 164, 512, 1600 and 5000 μg/plate were tested in triplicate in the tester strains TA100 and WP2uvrA, respectively.

Direct Plate Assay: Based on the results of the dose-range finding test, the following dose-range was selected for the mutation assay with the tester strains, TA1535, TA1537 and TA98 in the absence and presence of S9-mix: 5.4, 17, 52, 164, 512 and 1600 μg/plate.

Pre-Incubation Assay: Absence of S9-mix: 0.17, 0.54, 1.7, 5.4, 17 and 52 μg/plate; Presence of S9-mix: 1.7, 5.4, 17, 52, 164 and 512 μg/plate.
Vehicle / solvent:
- solvent used: Acetone
Controlsopen allclose all
Negative solvent / vehicle controls:
yes
Positive controls:
yes

Results and discussion

Test results
Species / strain:
other: All strains
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
cytotoxicity
Vehicle controls validity:
valid
Positive controls validity:
valid

Applicant's summary and conclusion

Conclusions:
Based on the results of this study it is concluded that Tri-n-butyl phosphine is not mutagenic in the Salmonella typhimurium reverse mutation assay and in the Escherichia coli reverse mutation assay.
Executive summary:

In this study, acceptable responses were obtained for the negative and strain-specific positive control items indicating that the test conditions were adequate and that the metabolic activation system functioned properly. The test item did not induce a significant dose-related increase in the number of revertant (His+) colonies in each of the four tester strains (TA1535, TA1537, TA98 and TA100) and in the number of revertant (Trp+) colonies in tester strain WP2uvrA both in the absence and presence of S9-metabolic activation. These results were confirmed in a follow-up experiment.