Methyl-1H-benzotriazole

Endpoint summary

Key value for chemical safety assessment

Genetic toxicity in vitro

Description of key information

A test for gene mutation in bacteria is available for the substance.

 

For the endpoint gene mutation in mammalian cells, no test with the substance is available.

As the former read-across to the proposed analogueous substance Benzotriazole (CAS 95-14-7) proofed to be scientifcly not adequate, a read-across based on a category developed in OECD QSAR Toolbox was used to fulfill the data gap which arose.
As the data gap was identified shortly before the deadline for submission,
a final evaluation is pending.

 

As a in vivo test for the endpoint cytogenicity is available, no in vitro test for this endpoint is needed.

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

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: well performed and documented study, no Guideline followed

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 471 (Bacterial Reverse Mutation Assay)

Version / remarks:

only 4 strains used

Principles of method if other than guideline:

Study performed according to the Ames test protocol

GLP compliance:

no

Type of assay:

bacterial reverse mutation assay

Target gene:

his-

Species / strain / cell type:

S. typhimurium TA 1535, TA 1537, TA 98 and TA 100

Metabolic activation:

with and without

Metabolic activation system:

S-9 rat liver

Test concentrations with justification for top dose:

20, 100, 500, 2500, 12500 µg/plate

Vehicle / solvent:

DMSO

Positive controls:

yes

Positive control substance:

sodium azide

other: Nitrofurantoin, 4-Nitro-1,2-phenylendiamin, 2-Aminoanthrazen

Details on test system and experimental conditions:

Method according to Maron, D. M.; Ames, B. N.; Mutation Res. 113, 173-215, 1983

Evaluation criteria:

positve is a reproducible, dose dependent increase of the mutation rate. The mutation rate should increase to twice the rate of the negative control.

Statistics:

mean and standard deviation

Species / strain:

S. typhimurium TA 1535, TA 1537, TA 98 and TA 100

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

cytotoxicity

Remarks:

above 2000 µg/plate

Untreated negative controls validity:

valid

Positive controls validity:

valid

Conclusions:

Interpretation of results (migrated information):
negative

The test item is cytotoxic to the used bacteria strains in doses above 2000 µg/plate.
Lower doses do not show this effect.
No mutagenic potential was observed in this study

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (negative)

Genetic toxicity in vivo

Description of key information

One in vivo study for the endpoint cytogenicity is available for the substance

Link to relevant study records

Reference

Endpoint:

in vivo mammalian somatic cell study: cytogenicity / erythrocyte micronucleus

Remarks:

Type of genotoxicity: chromosome aberration

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: well performed and documented study, no Guideline mentioned but equivalent to Guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 474 (Mammalian Erythrocyte Micronucleus Test)

GLP compliance:

yes

Type of assay:

micronucleus assay

Species:

mouse

Strain:

NMRI

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: F. Winkelmann, Borchen, Germany
- Age at study initiation: 8 - 12 weeks
- Weight at study initiation: 31 - 44 g
- Assigned to test groups randomly: [yes, under following basis: company randomising plan]
- Housing: standard Kakrolon cages type I and II
- Diet: Altromin 1324 ad libitum
- Water: ad libitum
- Acclimation period: 1 week

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22 +- 2°C
- Humidity (%): 50 %
- Air changes (per hr): 10
- Photoperiod (hrs dark / hrs light): 12

Route of administration:

oral: gavage

Vehicle:

- Vehicle(s)/solvent(s) used: Polyethylenglycole
- Justification for choice of solvent/vehicle: suitable solvent for Tolyltriazole
- Concentration of test material in vehicle: no data
- Amount of vehicle (if gavage or dermal): no data

Details on exposure:

PREPARATION OF DOSING SOLUTIONS: the test item was solved in polyethylene glycol and
administered by gavage

Duration of treatment / exposure:

not applicable

Frequency of treatment:

once

Post exposure period:

24 / 48 / 72 hours

Remarks:

Doses / Concentrations:
600 mg / kg bw
Basis:
nominal conc.

No. of animals per sex per dose:

5

Control animals:

yes, concurrent vehicle

Positive control(s):

cyclophosphamide
- Justification for choice of positive control(s): common substance, reommended by the OECD Guideline
- Route of administration: gavage
- Doses / concentrations: 20 mg / kg bw

Tissues and cell types examined:

bone marrow from the femur

Details of tissue and slide preparation:

CRITERIA FOR DOSE SELECTION: a range finding study indicated the dose

TREATMENT AND SAMPLING TIMES ( in addition to information in specific fields):

DETAILS OF SLIDE PREPARATION:
The bonemarrow is purged with fetal calve serum
Dyeing with an Ames Hema-Tek Slide Stainer

METHOD OF ANALYSIS:
manual counting with a microscope (magnification 1000)

Evaluation criteria:

for the test item the number of polychromatic cells with micro nuclei is compared to the controls
A difference is significant, if the error probability is below 5 %

Statistics:

distrribution free rank sum test according to wilcoxon
Chi2-Test
Mean values and 1s-range

Sex:

male/female

Genotoxicity:

negative

Toxicity:

yes

Vehicle controls validity:

valid

Positive controls validity:

valid

Additional information on results:

RESULTS OF RANGE-FINDING STUDY
- Dose range: 500 - 1000 mg/kg bw
- Clinical signs of toxicity in test animals: apathy, horrent fur, narcotic state, prone position, spasm, breathlessness

RESULTS OF DEFINITIVE STUDY
- Induction of micronuclei (for Micronucleus assay): normal
- Ratio of NCE/PCE (for Micronucleus assay): 1000:1715

Group	evaluable polychromatic Erythrocytes	Ratio NCE/PCE	Micronuclei per 1000 NCE	Micronuclei per 1000 PCE
negative control	10000	1320	0.5	1.2
Tolyltriazole, 24 h	10000	1540	0.9	1.7
Tolyltriazole, 48 h	10000	1715	0.6	1.4
Tolyltriazole, 72 h	10000	994	0.5	1.0
positive control	10000	1393	0.8	14.7

Conclusions:

Interpretation of results (migrated information): negative
Tolyltriazole does not show genetic toxicity in this study.
Toxic effects were observed in a range finding study at 750 mg /kg bw

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (negative)

Justification for classification or non-classification

The available information is conclusive but not sufficient for classification.