Diisobutyl phthalate

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:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Study conducted as part of the US National Toxicology Program. Article published in established peer-reviewed journal; standard protocol followed.

Data source

Reference

Reference Type:

review article or handbook

Title:

Phthalate ester testing in the National Toxicology Program’s Environmental Mutagenesis Test Development Program

Author:

Zeiger, E., Haworth, S., Speck, W., and Mortelmans, K.

Year:

1982

Bibliographic source:

Environmental Health Perspectives, 45, 99-101, 1982

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 471 (Bacterial Reverse Mutation Assay)

GLP compliance:

no

Type of assay:

bacterial reverse mutation assay

Test material

Test material information

Constituent 1

Reference substance name:

Diisobutyl phthalate

EC Number:

201-553-2

EC Name:

Diisobutyl phthalate

Cas Number:

84-69-5

Molecular formula:

C16H22O4

IUPAC Name:

diisobutyl phthalate

Details on test material:

Reagent grade

Method

Target gene:

Histidine prototrophy assay in Salmonella typhimurium (Ames test)

Species / strain

Species / strain / cell type:

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

Additional strain / cell type characteristics:

not specified

Metabolic activation:

with and without

Metabolic activation system:

S9/cofactors (exogenous metabolic activation

Test concentrations with justification for top dose:

100-10,000 µg/plate (recommended maximum for OECD 471 is 5,000 µg/plate)

Vehicle / solvent:

DIBP dissolved in DMSO.

Details on test system and experimental conditions:

Slight deficiency in number/type of bacterial strains with respect to OECD 471.
Doses/concentration: 100-10,000 µg/plate (recommended maximum for OECD 471 is 5,000 µg/plate).
Pre-incubation modification of the method of Ames et al.
Bacteria were tested for reversion to histidine prototrophy, both in the absence and presence of S9/cofactors (exogenous metabolic activation system). Concurrent positive and solvents controls were included to demonstrate the effective performance of the assays.

Evaluation criteria:

Testing conducted in a blind manner. Decoding of samples performed by NTP after data evaluation.
Concurrent positive and solvents controls were included to demonstrate the effective performance of the assays.
Treatment of data: A positive mutagenic response was defined as a reproducible, dose-related increase in his+ revertants over the spontaneous level.

Results and discussion

Test results

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:

not specified

Vehicle controls validity:

not specified

Untreated negative controls validity:

not specified

Positive controls validity:

valid

Remarks on result:

other: strain/cell type:

Remarks:

Migrated from field 'Test system'.

Applicant's summary and conclusion

Conclusions:

Interpretation of results (migrated information):
negative with metabolic activation
negative without metabolic activation

DIBP was not mutagenic in this assay, neither in the absence nor presence of an exogenous metabolic activation system.

Executive summary:

Bacteria were tested for reversion to histidine prototrophy, both in the absence and presence of S9/cofactors (exogenous metabolic activation system). Doses/concentration:100-10,000 µg/plate. Pre-incubation modification of the method of Ames et al. Concurrent positive and solvents controls were included to demonstrate the effective performance of the assays. DIBP was not mutagenic in this assay, with and without metabolic activation.