3-pyridyl dimethylcarbamate

Endpoint summary

Key value for chemical safety assessment

Genetic toxicity in vitro

Description of key information

GLP guideline study according to OECD 471

Link to relevant study records

Reference

Endpoint:

in vitro gene mutation study in bacteria

Type of information:

experimental study

Adequacy of study:

key study

Study period:

1999-04-06 to 1999-06-07

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 471 (Bacterial Reverse Mutation Assay)

Version / remarks:

Adopted 21st July 1997

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Type of assay:

bacterial reverse mutation assay

Specific details on test material used for the study:

- CAS No.: 51581-32-9
- Batch No.: TMFP 304
- Purity: at least 99 %
- Solubility in water: Soluble
- Date of expiry: December 1999
- Storage: In the refrigerator, in the dark
- Appearance: colorless liquid
- pH: 7.92

Target gene:

Histidine

Species / strain / cell type:

S. typhimurium, other: TA97a, TA98, TA100, TA102 and TA1535

Metabolic activation:

with and without

Metabolic activation system:

Aroclor 1254 rat homogenised liver (S9) activation system

Test concentrations with justification for top dose:

Test substance: 5000, 1667, 556, 185 and 62 µg / plate
The concentrations for the first experiment were set according to the preliminary toxicity test. At 5000 µg / plate, a reduction of the bacterial background was seen but the revertant colonies were normal and could be counted. 5000 µg / plate is the highest recommended concentration recommended for the Ames test.

Vehicle / solvent:

Vehicle used: None

Untreated negative controls:

yes

Negative solvent / vehicle controls:

not specified

True negative controls:

not specified

Positive controls:

yes

Positive control substance:

other: 4-Nitro-o-phenylene-diamine

Remarks:

-S9, TA97a, 10 µg / plate

Untreated negative controls:

yes

Negative solvent / vehicle controls:

not specified

True negative controls:

not specified

Positive controls:

yes

Positive control substance:

2-nitrofluorene

Remarks:

-S9, TA98, 2 µg / plate

Untreated negative controls:

yes

Negative solvent / vehicle controls:

not specified

True negative controls:

not specified

Positive controls:

yes

Positive control substance:

sodium azide

Remarks:

-S9, TA100, 2µg / plate ; TA1535, 1 µg / plate

Untreated negative controls:

yes

Negative solvent / vehicle controls:

not specified

True negative controls:

not specified

Positive controls:

yes

Positive control substance:

other: t-Butyl-hydroperoxide

Remarks:

-S9, TA102, 50 µg / plate

Untreated negative controls:

yes

Negative solvent / vehicle controls:

not specified

True negative controls:

not specified

Positive controls:

yes

Positive control substance:

7,12-dimethylbenzanthracene

Remarks:

+S9, TA97a, 5 µg / plate

Untreated negative controls:

yes

Negative solvent / vehicle controls:

not specified

True negative controls:

not specified

Positive controls:

yes

Positive control substance:

other: 2-Aminoanthracene

Remarks:

+S9, TA98, 1 µg / plate ; TA100, TA1535, 2 µg / plate

Untreated negative controls:

yes

Negative solvent / vehicle controls:

not specified

True negative controls:

not specified

Positive controls:

yes

Positive control substance:

other: 1,8 - Dihydroxy-anthraquinone

Remarks:

+S9, TA102, 50 µg / plate

Details on test system and experimental conditions:

METHOD OF APPLICATION: Plate incorporation assay in which bacteria, test substance (and microsomes) are in contact on the plate without preceding incubation in the liquid state. The number of viable cells in the overnight-cultures is in the range of 2 X 10^8 cells per ml.
For each sample the following solutions were combined:
- 0.1 mL of the overnight culture of the bacteria
- 0.5 mL of S9-mix (or phosphate buffered saline for samples without metabolic activation)
- 0.1 mL of the appropriate test- or reference substance solution and
- 2 mL of top agar

The combined solutions were mixed and spread over a plate with minimal agar (9 cm diameter). After the top agar had solidified, the plates were incubated at 37 °C until the colonies were visible (2 days).

Rationale for test conditions:

No specified

Evaluation criteria:

The criteria for a positive result are:
A reproducible increase of the number of revertants to more than the following threshold values for at least one of the concentrations:
- For the strains with a low spontaneous revertant rate i.e. TA98 and TA1535: The twofold of the amount of the spontaneous revertants
- For the strains with a high spontaneous revertant rate i.e. TA97a, TA100 and TA102: The 1 2/3 fold of the amount of the spontaneous revertants.
These threshold values were derived from the variations in the control samples of our historic data of the Ames test.

Key result

Species / strain:

S. typhimurium, other: TA97a, TA98, TA100, TA102 and TA1535

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity

Vehicle controls validity:

not specified

Untreated negative controls validity:

valid

Positive controls validity:

valid

Additional information on results:

- Positive control substances: All positive control substances increased the mutation frequency to more than the threshold
- Solubility: The test substance was sufficiently soluble in water, no precipitation of the test substance was visible in any stage of the experiments

Conclusions:

In this study, the test item was classified as non-mutagenic in an Ames test according to OECD 471 under the UN GHS Criteria.

Executive summary:

In a reverse bacterial mutation test, conducted according to OECD guideline 471, strains of Salmonella typhimurium TA97a, TA98, TA100, TA102 and TA1535 were exposed to the test item dissolved in water at concentrations ranging from 62 to 5000 µg / plate according to the direct plate incorporation method in the presence and absence of an external S9 metabolising system. All positive control groups showed significantly increased mutation frequencies which demonstrate the sensitivity of the test system. No increase in the mutation frequency to more than the threshold values was obtained in any of the concentrations tested. Based on these results, the test item is considered non-mutagenic according to the UN GHS Criteria.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (negative)

Genetic toxicity in vivo

Endpoint conclusion

Endpoint conclusion:

no study available

Justification for classification or non-classification

No increase in the mutation frequency was obtained in any of the concentrations tested in a GLP guideline study according to OECD 471. Based on these results, the test item is considered non-mutagenic.