6H-dibenz[c,e][1,2]oxaphosphorin 6-oxide

Endpoint summary

Key value for chemical safety assessment

Genetic toxicity in vitro

Description of key information

The test substance Ukanol GK-F is thus classified as “not mutagenic under the test conditions”.

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:

Date of test protocol: 01.08.2007; Start of experimental phase: 12.09.2007; Completion of experimental phase: 21.09.2007; Preliminary report: 24.09.2007; Final report: 08.10.2007

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Performed according to GLP, OECD guidelines followed and no deviations reported

Justification for data waiving:

other:

Reason / purpose for cross-reference:

reference to same study

Reason / purpose for cross-reference:

reference to other study

Qualifier:

according to guideline

Guideline:

OECD Guideline 471 (Bacterial Reverse Mutation Assay)

Deviations:

no

Qualifier:

according to guideline

Guideline:

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

Deviations:

no

Principles of method if other than guideline:

The following literature was additionally used:
“Revised Methods for the Salmonella Mutagenicity Test” by Dorothy Maron and Prof. Bruce Ames, Mutation Research 113 (1983), p.173-215

Corresponding LAUS GmbH SOP:
SOP 118 008 03, Version 6 of 13 Nov. 2006
“Bestimmung des erbgutverändernden Potentials mit dem Bacterial-Reverse-Mutation-Test (Ames-Test)” [Determination of mutagenic potential using the bacterial reverse mutation test (Ames test)]

GLP compliance:

yes (incl. QA statement)

Type of assay:

bacterial reverse mutation assay

Target gene:

See attached report

Species / strain / cell type:

S. typhimurium, other: Salmonella typhimurium LT2; Strains TA 1535, TA 97a, TA 98, TA 100 and TA 102

Additional strain / cell type characteristics:

not specified

Metabolic activation:

with and without

Metabolic activation system:

S9 mix

Test concentrations with justification for top dose:

Experiment 1: 5024, 1507, 502, 151, 50 µg/plate
Experiment 2: 5014, 2507, 1254 µg/plate

Vehicle / solvent:

DMSO

Untreated negative controls:

no

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

sodium azide

benzo(a)pyrene

other: 4-nitro-1,2-phenylenediamine, 2-aminoanthracene

Details on test system and experimental conditions:

See Attached report

Evaluation criteria:

see attached report

Statistics:

No details provided in report

Species / strain:

S. typhimurium TA 1535

Metabolic activation:

with and without

Genotoxicity:

not determined

Cytotoxicity / choice of top concentrations:

no cytotoxicity

Vehicle controls validity:

valid

Untreated negative controls validity:

not specified

Positive controls validity:

valid

Remarks on result:

other: all strains/cell types tested

Remarks:

Migrated from field 'Test system'.

The detailed results can be found in the annex to the attached report.

 

- First experiment

Validation of the criteria: The controls used to validate the genotype and the sterility control met all necessary criteria. Revertant counts were within the frequency range expected from the test facility’s historical data for the batches used to demonstrate the titre, spontaneous revertants and positive controls (for historical data see Annex 4 of attached report: Comparison of historical data, see Page 34).

 

Solubility and toxicity: The test substance was dissolved in DMSO. A stock solution was prepared with a concentration of 50 mg/I.

There were no signs of toxicity in the strains tested. The background lawn was visible and the number of spontaneous revertants was not reduced.

 

Mutagenicity: No significant increase in the number of revertants with and without metabolic activation was observed. No dose-response relationship was observed. On the basis of this experiment, the test substance Ukanol GK-F is classified as “not mutagenic under the test conditions”.

 

A second experiment was performed with modified test parameters to validate these results.

 

- Second experiment

Validation of the criteria: The controls used to validate the genotype, the sterility control and the titre control fulfilled all relevant criteria. Revertant counts were within the frequency range expected from the test facility’s historical data for the spontaneous revertants and the positive controls.

 

Solubility and toxicity: The test substance was dissolved in DMSO. A stock solution was prepared with a concentration of 50 mg/I. There were no signs of toxicity in the strains tested. The background lawn was visible and the number of spontaneous revertants was not reduced.

 

Mutagenicity: No significant increase in the number of revertants with and without metabolic activation was observed. No dose-response relationship was observed. On the basis of this experiment, the test substance Ukanol GK-F is classified as “not mutagenic under the test conditions”.

 

- Results: The test substance had no mutagenic effect in any experiment. The revertant counts were not significantly increased in comparison with the spontaneous revertants. No dose-response relationship was observed. No cytotoxicity was observed. The background lawn was visible and the number of revertants was not significantly reduced. Under the test conditions, the test substance Ukanol GK-F can be classified as non-mutagenic in the reverse mutation test with Salmonella typhimurium strains TA 97a, TA 98, TA 100, TA 102 and TA 1535.

 

- Discussion: The test substance Ukanol GK-F is classified as non-mutagenic for the aforementioned reasons. No toxic effect on the bacteria was observed.

 

Mutations in the positive controls were lower than specified by Prof. Ames, but within the frequency range expected from LAUS GmbH’s historical control data (see Annex 4 of attached report: Comparison of historical data, page 34). An increased mutation rate (induction rate > 2) was established beyond doubt in all strains and all experiments with and without metabolic activation.

 

Quarterly genotype validation was ok. The titre values for each experiment were above the required value.

 

Although some of the spontaneous revertants were below the range specified by Prof. Ames, they were nonetheless within the usual range expected from LAUS GmbH’s historical data.

It can thus be assumed that the test results are valid.

Conclusions:

Interpretation of results (migrated information):
negative

Ukanol GK-F showed no mutagenic effect in Salmonella typhimurium, strains TA97a, TA98, TA100, TA102 and TA1535 under the test conditions. No dose-response relationship was observed.

Executive summary:

Two valid experiments were conducted.

 

First experiment: The test substance was dissolved in DMSO. Five concentrations were tested in the plate incorporation method (range 5024 to 50 µg/plate). The batches were incubated for 48 hours with genetically altered histidine-deficient strains of Salmonella typhimurium; TA 97a, TA 98, TA 100, TA 102 and TA 1535 strains were used each with and without a metabolic activation system.

 

No increase in revertants was detected in any of the concentrations tested. Thus there was no evidence of mutagenic effect.

 

The test substance had no toxic effect on the test strains.

 

The sterility and titre control showed no signs of irregularities. The figures obtained for spontaneous revertants in the negative controls lay within the usual range, all positive controls induced a clear mutagenic response both with and without metabolic activation.

 

Second experiment: To validate these results, the test was repeated with three concentrations (5014 to 1254 µg/plate) under modified experimental conditions. The preincubation method was used.

 

In this experiment too, the test substance showed no mutagenic or toxic effect in the test strains.

 

The sterility control was ok. The figures obtained for the titre control and the spontaneous revertants in the negative controls lay within the usual range, all positive controls induced a clear mutagenic response both with and without metabolic activation.

Ukanol GK-F showed no mutagenic effect in Salmonella typhimurium, strains TA97a, TA98, TA100, TA102 and TA1 535 under the test conditions. No dose-response relationship was observed.

 

The test substance Ukanol GK-F is thus classified as “not mutagenic under the test conditions”.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (negative)

Additional information

Additional information from genetic toxicity in vitro:

First experiment: The test substance was dissolved in DMSO. Five concentrations were tested in the plate incorporation method (range 5024 to 50 µg/plate). The batches were incubated for 48 hours with genetically altered histidine-deficient strains of Salmonella typhimurium; TA 97a, TA 98, TA 100, TA 102 and TA 1535 strains were used each with and without a metabolic activation system. No increase in revertants was detected in any of the concentrations tested. Thus there was no evidence of mutagenic effect. The test substance had no toxic effect on the test strains. The sterility and titre control showed no signs of irregularities. The figures obtained for spontaneous revertants in the negative controls lay within the usual range, all positive controls induced a clear mutagenic response both with and without metabolic activation.

 

Second experiment: To validate these results, the test was repeated with three concentrations (5014 to 1254 µg/plate) under modified experimental conditions. The preincubation method was used. In this experiment too, the test substance showed no mutagenic or toxic effect in the test strains.

 

The sterility control was ok. The figures obtained for the titre control and the spontaneous revertants in the negative controls lay within the usual range, all positive controls induced a clear mutagenic response both with and without metabolic activation. Ukanol GK-F showed no mutagenic effect in Salmonella typhimurium, strains TA97a, TA98, TA100, TA102 and TA1 535 under the test conditions. No dose-response relationship was observed.

 

The test substance Ukanol GK-F is thus classified as “not mutagenic under the test conditions”.

Justification for selection of genetic toxicity endpoint
Key Study