Isobutyryl chloride

Genetic toxicity: in vitro

Administrative data

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:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP compliant guideline study, available as unpublished report, no restrictions, fully adequate for assessment.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1998

Report date:

1998

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 471 (Bacterial Reverse Mutation Assay)

Test guideline 2

Qualifier:

according to guideline

Guideline:

OECD Guideline 472 (Genetic Toxicology: Escherichia coli, Reverse Mutation Assay)

Test guideline 3

Qualifier:

according to guideline

Guideline:

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

GLP compliance:

yes

Type of assay:

bacterial reverse mutation assay

Test material

Test material information

Constituent 1

Reference substance name:

Isobutyryl chloride

EC Number:

201-194-1

EC Name:

Isobutyryl chloride

Cas Number:

79-30-1

Molecular formula:

C4H7ClO

IUPAC Name:

2-methylpropanoyl chloride

Details on test material:

- Name of test material (as cited in study report): Isobuttersäurechlorid
- Analytical purity: 99.5 %
- Batch number: Vers. 99/V
- Test substance number: 96/505
- Physical state: colorless liquid
- Storage condition of test material: room temperature

Method

Target gene:

his

Species / strain

Species / strain / cell type:

S. typhimurium TA 1535, TA 1537, TA 98, TA 100 and E. coli WP2

Metabolic activation:

with and without

Metabolic activation system:

Aroclor 1254-induced rat liver S-9 mix

Test concentrations with justification for top dose:

0, 20, 100, 500, 2500, 5000 µg/plate (standard plate test; first test)
0, 20, 100, 500, 1000, 1500 µg/plate (standard plate test; second test)
0, 0.8, 4, 20, 100, 500 µg/plate (preincubation test)

Vehicle / solvent:

- Vehicle(s)/solvent(s) used: DMSO
- Justification for choice of solvent/vehicle: Due to the limited solubility of the test substance in water, DMSO was selected as the vehicle, which had been demonstrated to be suitable in bacterial reverse mutation tests and for which historical control data are available.

Controls

Controls 1

Untreated negative controls:

yes

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

other: 2-aminoanthracene

Remarks:

with S-9 mix for strains TA 1535, TA 100, TA 1537, TA 98 and E.coli WP2 uvrA

Controls 2

Untreated negative controls:

yes

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

other: N-methyl-N'-nitro-N-nitrosoguanidine

Remarks:

without S-9 mix for strains TA 1535 and TA 100

Controls 3

Untreated negative controls:

yes

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

other: 4-nitro-o-phenyldiamine

Remarks:

without S-9 mix for strain TA 98

Controls 4

Untreated negative controls:

yes

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

9-aminoacridine

Remarks:

without S-9 mix for strain TA 1537

Controls 5

Untreated negative controls:

yes

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

N-ethyl-N-nitro-N-nitrosoguanidine

Remarks:

without S-9 mix for strain E.coli WP2 uvrA

Details on test system and experimental conditions:

METHOD OF APPLICATION: in agar (plate incorporation); preincubation

DURATION
Plate incorporation method:
- Exposure duration: ca. 48-72 hours at 37°C
Preincubation method:
- Preincubation period: 20 minutes at 37°C
- Exposure duration: ca. 48-72 hours at 37°C

NUMBER OF REPLICATIONS:
- 3 test plates per dose or per control

DETERMINATION OF CYTOTOXICITY
- Decrease in the number of revertants
- Reduced his- or trp- background growth
- Reduction in the titer

Evaluation criteria:

The test chemical is considered positive in this assay if a dose-related and reproducible increase in the number of revertant colonies (i.e. about doubling of the spontaneous mutation rate) in at least one tester strain is observed either without S-9 mix or after adding a metabolizing system.
A test substance is generally considered nonmutagenic in this test if the number of revertants for all tester strains were within the historical negative control range under all experimental conditions in two experiments carried out independently of each other.

Results and discussion

Test results

Species / strain:

S. typhimurium TA 1535, TA 1537, TA 98, TA 100 and E. coli WP2

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

cytotoxicity

Remarks:

at concentrations of ≥1000 µg/plate in the standard plate test and ≥100 µg/plate in the preincubation assay

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

Positive controls validity:

valid

Additional information on results:

ADDITIONAL INFORMATION ON CYTOTOXICITY:
A bacteriotoxic effect (reduced his- or trp- background growth, decrease in the number of his+ or trp+ revertants, reduction in the titer) was observed at doses ≥ 1000 µg/plate onward (standard plate test) or ≥ 100 µg/plate (preincubation assay).

SOLUBILITY:
No precipitation of the test substance was found.

Remarks on result:

other: all strains/cell types tested

Remarks:

Migrated from field 'Test system'.