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Toxicological information

Genetic toxicity: in vivo

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Administrative data

Endpoint:
in vivo mammalian somatic cell study: cytogenicity / bone marrow chromosome aberration
Remarks:
Type of genotoxicity: chromosome aberration
Type of information:
experimental study
Adequacy of study:
key study
Study period:
According to the NTP website the start dates for the three studies were 31 August 1987, 17 December 1987 and 22 August 1988
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Little data on methods used or on animal husbandry. Full results on types of aberrations detected not reported; the mitotic index was not determined as an indicator of toxicity to the bone marrow cells.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1997
Report Date:
1997

Materials and methods

Test guideline
Qualifier:
equivalent or similar to
Guideline:
EPA OPPTS 870.5385 (In Vivo Mammalian Cytogenetics Tests: Bone Marrow Chromosomal Analysis)
Deviations:
yes
Remarks:
cytotoxicity not determined; only 50 metaphases examined per animal
GLP compliance:
not specified
Type of assay:
chromosome aberration assay

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
- Name of test material (as cited in study report): butyl benzylphthalate
- Physical state: solid
- Analytical purity: no data
- Impurities (identity and concentrations): no data
- Composition of test material, percentage of components:
- Isomers composition: no data
- Purity test date: no data
- Lot/batch No.: no data
- Expiration date of the lot/batch: no data
- Stability under test conditions: no data
- Storage condition of test material: no data
- Other:

Test animals

Species:
mouse
Strain:
B6C3F1
Sex:
male
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: no data
- Age at study initiation: no data
- Weight at study initiation: no data
- Assigned to test groups randomly: [no/yes, under following basis: ] no data
- Fasting period before study: no data
- Housing: no data
- Diet (e.g. ad libitum): no data
- Water (e.g. ad libitum): no data
- Acclimation period: no data


ENVIRONMENTAL CONDITIONS
- Temperature (°C): no data
- Humidity (%): no data
- Air changes (per hr): no data
- Photoperiod (hrs dark / hrs light): no data


IN-LIFE DATES: From: To:

Administration / exposure

Route of administration:
intraperitoneal
Vehicle:
- Vehicle(s)/solvent(s) used: corn oil
- Justification for choice of solvent/vehicle: no data
- Concentration of test material in vehicle: no data
- Lot/batch no. (if required): no data
- Purity: no data
Details on exposure:
intraperitoneal injection of 0.4 ml
Duration of treatment / exposure:
single injection
Frequency of treatment:
single injection
Post exposure period:
17 hr (2 studies); 36 hr (1 study)
Doses / concentrationsopen allclose all
Remarks:
Doses / Concentrations:
0, 1250, 2500, or 5000 mg/kg bw
Basis:
nominal conc.
Study 1: 36 hr sampling time
Remarks:
Doses / Concentrations:
0, 1250, 2500, or 5000 mg/kg bw
Basis:
nominal conc.
Study 2: 17 hr sampling time
Remarks:
Doses / Concentrations:
0, 2500, 3750 or 5000 mg/kg bw
Basis:
nominal conc.
Study 3: 17 hr sampling time
No. of animals per sex per dose:
8 males per dose
Positive control(s):
dimethylbenzanthracene
- Justification for choice of positive control(s): no data
- Route of administration: not specified but presumably i.p.
- Doses / concentrations:100 mg/kg bw

Examinations

Tissues and cell types examined:
bone marrow cells
Details of tissue and slide preparation:
CRITERIA FOR DOSE SELECTION: based on available information on LD50 values. Highest dose "limited by experimental design" to 5000 mg/kg bw

TREATMENT AND SAMPLING TIMES ( in addition to information in specific fields): for the 17 hr sampling time the mice were implanted subcutaneously with a bromodeoxyuridine tablet 1 hr before exposure to BBP (to allow selection of cells in the first metaphase following treatment for scoring). Mice sampled at 36 hr were implanted subcutaneously with a bromodeoxyuridine tablet 18 hr after exposure to BBP. The mice received an i.p. injection of colchicine 2 hrs before sacrifice.


DETAILS OF SLIDE PREPARATION: Bone marrow cells were flushed from the femurs with phosphate-buffered saline, treated with a hypotonic salt solution, fixed and dropped onto chilled slides. After drying in air for 24 hr, the slides were stained.


METHOD OF ANALYSIS: 50 first-division metaphases were scored from each of the eight animals for all types of aberrations. The mean number of cells with aberrations (excluding gaps) and the mean total aberrations were determined for each treatment group.


OTHER:
Statistics:
The values for the percentage of cells with aberrations were analysed by a one-tailed trend test, and the significance was set at P=0.025

Results and discussion

Test resultsopen allclose all
Sex:
male
Genotoxicity:
positive
Remarks:
17 hr sampling time; at 5000 mg/kg bw only (2 studies)
Toxicity:
not specified
Vehicle controls valid:
yes
Negative controls valid:
not applicable
Positive controls valid:
yes
Sex:
male
Genotoxicity:
negative
Remarks:
36 hr sampling time (1 study)
Toxicity:
not specified
Vehicle controls valid:
yes
Negative controls valid:
not applicable
Positive controls valid:
yes
Additional information on results:
RESULTS OF RANGE-FINDING STUDY: not carried out


RESULTS OF DEFINITIVE STUDY
- Types of structural aberrations for significant dose levels (for Cytogenetic or SCE assay): not given in report
- Appropriateness of dose levels and route: appropriate, single i.p. injection
- Statistical evaluation: significant (P=0.003) at 5000 mg/kg bw dose at 17hr sampling time in both studies (studies 2 and 3).

Any other information on results incl. tables

 Butyl benzyl phthalate gave a weak positive result at a dose of 5000 mg/kg bw when sampled at 17 hr post treatment only. Trend analysis was also positive in studies 2 and 3 (p=0.003)

 

Study 1 (36 hr sampling)

Study 2 (17 hr sampling)

Study 3 (17 hr sampling)

 

Dose

(mg/kg bw)

% cells with

aberrations

Dose

(mg/kg bw)

% cells with

aberrations

Dose

(mg/kg bw)

% cells with

aberrations

 Corn oil    0.25    0.75    1.00
 DMBA  100  26.75  100  11.50  100  14.00
 BBP  1250  1.50  1250  1.50  2500  2.25
   2500  0.25  2500  0.75  3750  2.00
   5000  0.50  5000  3.25*  5000  4.25*

* P=0.006

Applicant's summary and conclusion

Conclusions:
Interpretation of results (migrated information): other: weak positive
In an in vivo assay for chromosome aberrations in which mice were treated by a single intraperitoneal injection, butyl benzyl phthalate showed a weak positive response in the bone marrow at the top dose of 5000 mg/kg bw.
Executive summary:

Butyl benzyl phthalate was assessed for its ability to induce chromosome aberrations in the bone marrow cells of mice.

In two separate studies, groups of eight male mice were injected intraperitoneally with either 0, 1250, 2500 or 5000 mg/kg bw of the test compound, another group received dimethylbenzanthracene (positive control) and cells were harvested at either 17 or 36 hr after treatment. In a further study mice were dosed with 0, 2500, 3750 or 5000 mg/kg bw and cells were harvested at 17 hr. The mice were subcutaneously implanted with a bromodeoxyuridine tablet 18 hr before harvesting, and injected with colchicine 2 hr before harvesting of the cells. Bone marrow cells were collected from the femurs of each animal, washed, fixed and spread on slides before staining. Fifty first-division metaphases from each animal were scored for all types of chromosome aberrations. The mean number of aberrations and the mean percentage of cells containing aberrations (excluding gaps) were determined for each treatment group. The mitotic index was not determined as an indicator of cytotoxicity.

In both studies in which cells were harvested at 17 hr post treatment, a weak (but statistically significant) increase in aberrations was seen only at 5000 mg/kg bw. There was no such increase at the delayed 36-hr sampling time.

In an in vivo assay for chromosome aberrations in which mice were treated by a single intraperitoneal injection, butyl benzyl phthalate showed a weak positive response in the bone marrow at the top dose of 5000 mg/kg bw.