tert-butyl perbenzoate

Genetic toxicity: in vitro

Administrative data

Endpoint:

in vitro DNA damage and/or repair study

Remarks:

Type of genotoxicity: other: SCE

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

March, 1985 - July, 1988

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Remarks:

Well executed and reported study subjected to peer review and conducted according to modern standards, including GLP.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1992

Report date:

1992

Materials and methods

Principles of method if other than guideline:

No guidelines are cited in the source document. A detailed description of the SCE protocol is presented by Galloway et al. (1985, 1987). Briefly, Chinese hamster ovary cells were incubated with study compound or solvent (dimethylsulfoxide) as described in (c) and (d) below, and cultured for sufficient.
time to reach second metaphase division. Cells were then collected by mitotic shake-off, fixed, air-dried, and stained.

GLP compliance:

yes

Remarks:

NTP follows GLP as a matter of policy

Type of assay:

sister chromatid exchange assay in mammalian cells

Test material

Test material information

Constituent 1

Reference substance name:

tert-butyl perbenzoate

EC Number:

210-382-2

EC Name:

tert-butyl perbenzoate

Cas Number:

614-45-9

Molecular formula:

C11H14O3

IUPAC Name:

tert-butyl benzenecarboperoxoate

Method

Species / strain

Species / strain / cell type:

Chinese hamster Ovary (CHO)

Metabolic activation:

with and without

Metabolic activation system:

Arochlor 1254 induced liver homogenate from SD rats

Test concentrations with justification for top dose:

0.0, 0.16, 0.50, 1.60, 5.00, 16.00, 50.0 ug/ml

Vehicle / solvent:

dimethylsulfoxide (DMSO)

Controls

Negative solvent / vehicle controls:

yes

Remarks:

DMSO

Positive controls:

yes

Positive control substance:

cyclophosphamide

Remarks:

Migrated to IUCLID6: mitomycin

Details on test system and experimental conditions:

A detailed description of the SCE protocol is presented by Galloway et al. (1985, 1987). Briefly, Chinese hamster ovary cells were incubated with study compound or solvent (dimethylsulfoxide) as described in (c) and (d) below, and cultured for sufficient time to reach second metaphase division. Cells were then collected by mitotic shake-off, fixed, air-dried, and stained.

In the absence of S9, cells were incubated with study compound or solvent for 2 h at 37°C. Then BrdU was added and incubation was continued for 24 h. Cells were washed, fresh medium containing BrdU and colcemid was added, and incubation was continued for 2-3 h.

In the presence of S9, cells were incubated with study compound or solvent for 2 h at 37°C. The cells were then washed, and medium containing BrdU was added. Cells were incubated for a further 26 h, with colcemid present for the final 2-3 h. S9 was from the livers of Aroclor 1254-induced male Sprague Dawley rats.

Statistics:

Trend test

Results and discussion

Test results

Test results 1

Species / strain:

Chinese hamster Ovary (CHO)

Metabolic activation:

with

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity

Vehicle controls validity:

valid

Positive controls validity:

valid

Test results 2

Species / strain:

Chinese hamster Ovary (CHO)

Metabolic activation:

without

Genotoxicity:

positive

Cytotoxicity / choice of top concentrations:

cytotoxicity

Vehicle controls validity:

valid

Positive controls validity:

valid

Any other information on results incl. tables

See pp B-4 and B-5 of attached study report.

Applicant's summary and conclusion

Conclusions:

t-BP-induced sister-chromatid exchange in Chinese hamster ovary cells in vitro, only in the absence of S9 fraction.

Executive summary:

t-BP-induced sister-chromatid exchange in Chinese hamster ovary cells in vitro, only in the absence of S9 fraction.