Xylene

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

Study period:

not specified

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: GLP status not known, near guideline study, published in peer reviewed literature, no restrictions, fully adequate for assessment.

Justification for type of information:

N/A

Data source

Reference

Reference Type:

publication

Title:

Unnamed

Year:

1983

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 471 (Bacterial Reverse Mutation Assay)

Deviations:

yes

Remarks:

TA102 not used

Principles of method if other than guideline:

Liquid preincubation protocol using Salmonella strains TA98, TA100, TA1535 and TA1537 in the absence or presence of liver S9 from male Sprague-Dawley rats and Syrian hamsters induced with Aroclor 1254.

GLP compliance:

not specified

Type of assay:

bacterial reverse mutation assay

Test material

Test material information

Constituent 1

Reference substance name:

o-xylene

EC Number:

202-422-2

EC Name:

o-xylene

Cas Number:

95-47-6

Molecular formula:

C8H10

IUPAC Name:

o-xylene

Details on test material:

supplied by Aldrich, Lot number HD061297

Specific details on test material used for the study:

not specified

Method

Target gene:

not specified

Species / strain

Species / strain / cell type:

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

Cytokinesis block (if used):

N/A

Metabolic activation:

with and without

Metabolic activation system:

rat liver S-9, Aroclor 1254 induced; hamster liver S-9, Aroclor 1254 induced

Test concentrations with justification for top dose:

0, 1.0, 3.3, 10.0, 33.0, 100.0, 333.0 µg/plate

Vehicle / solvent:

- Vehicle(s)/solvent(s) used: DMSO

Controls

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

other: 2-Aminoanthracene, 4-Nitro-o-phenylenediamine, sodium azide, 9-aminoacridine

Remarks:

Positive and true negative controls tested as coded samples

Details on test system and experimental conditions:

METHOD OF APPLICATION: liquid preincubation

DURATION
- Preincubation period: 20 mins
- Exposure duration: 48 hours

NUMBER OF REPLICATIONS: Three plates were used and the experiment was repeated at least 1 week after completion of the initial test.

DETERMINATION OF CYTOTOXICITY
- Method: relative total growth

Rationale for test conditions:

not specified

Evaluation criteria:

Initially data were evaluated in an ad hoc manner. A positive response was indicated by a reproducible, dose-related increase, whether or not it was twofold over background.

Statistics:

The data were evaluated using an analysis based on models presented by Margolin et al, 1981 (methods not described).

Results and discussion

Test results

Test results 1

Key result

Species / strain:

S. typhimurium TA 1535

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity

Vehicle controls validity:

valid

Untreated negative controls validity:

not examined

True negative controls validity:

not examined

Positive controls validity:

valid

Test results 2

Key result

Species / strain:

S. typhimurium TA 1537

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity

Vehicle controls validity:

valid

Untreated negative controls validity:

not examined

True negative controls validity:

not examined

Positive controls validity:

valid

Test results 3

Key result

Species / strain:

S. typhimurium TA 98

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity

Vehicle controls validity:

valid

Untreated negative controls validity:

not examined

True negative controls validity:

not examined

Positive controls validity:

valid

Test results 4

Key result

Species / strain:

S. typhimurium TA 100

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

cytotoxicity

Remarks:

>100 µg/plate without activation and >333 µg/plate with activation

Vehicle controls validity:

valid

Untreated negative controls validity:

not examined

True negative controls validity:

not examined

Positive controls validity:

valid

Test results 5

Species / strain:

S. typhimurium TA 102

Remarks:

strain not tested

Metabolic activation:

not applicable

Genotoxicity:

not determined

Cytotoxicity / choice of top concentrations:

not determined

Vehicle controls validity:

not examined

Untreated negative controls validity:

not examined

True negative controls validity:

not examined

Positive controls validity:

not examined

Additional information on results:

N/A

Remarks on result:

other: all strains/cell types tested

Any other information on results incl. tables

N/A

Applicant's summary and conclusion

Conclusions:

Interpretation of results:
negative

negative with and without metabolic activation

Executive summary:

o-xylene was not genotoxic when tested with and without metabolic activation in Salmonella typhimurium strains TA98, TA100, TA1535 and TA1537 at concentrations up to 100 µg/plate (limit of cytotoxicity) using a liquid preincubation procedure and with metabolic activation at a concentration of 333 µg/plate.