Dimethyl phthalate

Genetic toxicity: in vivo

Administrative data

Endpoint:

in vivo mammalian somatic cell study: cytogenicity / erythrocyte micronucleus

Remarks:

Type of genotoxicity: chromosome aberration

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: see 'Remark'

Remarks:

The study was conducted according to standrad NTP protocols for mammalian testing of chromosome aberration (micronucleus formation) and is comparable to OECD TG 475. The study is reliable with acceptable restrictions: GLP-status is unclear, doses are applied three times every 24h, limited documentation (online file).

Data source

Reference

Reference 1

Reference Type:

publication

Title:

Unnamed

Year:

1994

Reference 2

Reference Type:

secondary source

Title:

No information

Author:

ECB-IUCLID

Year:

2000

Bibliographic source:

European Chemicals Bureau, 11-FEB-2000

Materials and methods

Principles of method if other than guideline:

Method: other: NTP standard protocol (Micronucleus in mouse bone marrow)

GLP compliance:

not specified

Type of assay:

micronucleus assay

Test material

Test material information

Constituent 1

Reference substance name:

Dimethyl phthalate

EC Number:

205-011-6

EC Name:

Dimethyl phthalate

Cas Number:

131-11-3

Molecular formula:

C10H10O4

IUPAC Name:

1,2-dimethyl benzene-1,2-dicarboxylate

Test material form:

liquid

Specific details on test material used for the study:

- Name of test material (as cited in study report): Dimethyl phthalate

Test animals

Species:

mouse

Strain:

B6C3F1

Sex:

male

Administration / exposure

Route of administration:

intraperitoneal

Vehicle:

- Vehicle(s)/solvent(s) used: corn oil

Details on exposure:

route of exposure: intraperitoneal injection

Duration of treatment / exposure:

72 h; 3 x i.p.

Doses / concentrations

Doses / concentrations 1

Dose / conc.:

750 mg/kg bw/day (nominal)

Remarks:

intraperitoneal injection

Doses / concentrations 2

Dose / conc.:

1 500 mg/kg bw/day (nominal)

Remarks:

intraperitoneal injection

Doses / concentrations 3

Dose / conc.:

2 250 mg/kg bw/day (nominal)

Remarks:

intraperitoneal injection

Doses / concentrations 4

Dose / conc.:

3 000 mg/kg bw/day (nominal)

Remarks:

intraperitoneal injection

No. of animals per sex per dose:

5M per treatment and 4M in vehicle/positive control

Control animals:

yes, concurrent vehicle

Positive control(s):

cyclophosphamide
- Route of administration: intraperitoneal injection
- Doses / concentrations: 25mg/kg bw

Examinations

Tissues and cell types examined:

bone marrow and erythrocytes are examined for presence of micronuclei

Details of tissue and slide preparation:

TREATMENT AND SAMPLING TIMES (in addition to information in specific fields):
- Treatment: 3 treatments every 24h, duration 72h
- Sampling: 24h after last dosing
- The bone marrow is flushed from the femurs and spread onto slides.

DETAILS OF SLIDE PREPARATION:
- The slides are air-dried, fixed and stained with a fluorescent DNA-specific dye that illuminates any micronuclei that may be present.

Statistics:

Formal statistical analysis:
- trend test (cells containing micronuclei)
- pairwise comparison of each dose group to the corresponding control
- Data are typically presented as the mean number of micronucleated cells per 1,000 cells for each treatment group

Results and discussion

Test results

Sex:

male

Genotoxicity:

negative

Toxicity:

not specified

Vehicle controls validity:

valid

Negative controls validity:

valid

Positive controls validity:

valid

Additional information on results:

RESULTS OF DEFINITIVE STUDY
- Induction of micronuclei (for Micronucleus assay): yes, positive control was valid
- Ratio of PCE/NCE (for Micronucleus assay): no
- Appropriateness of dose levels and route: yes
- Statistical evaluation: yes

Any other information on results incl. tables

Table1:

Start Date	Sample Collection Time	Sex	Cell	Dosing Regimen	Trend Test P-Value
03/15/1994	24 Hours	Male	PCE	IP x 3, 72 Hours	0.166
		Dose (mg/kg)	No. of Animals Scored	Mean MN-PCE/1000 PCE ± SEM	Pairwise P
Vehicle Control:	Corn Oil	0	4	1.00 ± 0.00
Test Chemical:		750	5	0.90 ± 0.33	0.586
		1500	5	1.20 ± 0.30	0.344
		2250	5	0.70 ± 0.30	0.756
		3000	5	1.60 ± 0.29	0.137
Positive Control:	Cyclophosphamide	25	4	3.63 ± 0.69	0.000

Applicant's summary and conclusion

Conclusions:

Interpretation of results (migrated information): negative
No chromosome aberration was detected in male B6C3F1 mice at doses up to 3000 mg/kg bw.
Test substance was not mutagenic.

Executive summary:

The study was conducted according to standard NTP protocol for mammalian bone marrow chromosome aberration testing of chemicals which is comparable to OECD Guideline 475. GLP

status is unclear. Acceptable restriction: doses are applied three times every 24h, limited documentation (online file).

Male B6C3F1 mice were exposed to dose levels of 0, 750, 1500, 2250 and 3000 mg/kg bw (5 animals/treatment) three times every 24h (72h duration) via intraperitoneal injection. 24h after the last application bone marrow was analyzed for presence of micronuclei in polychromatic erythrocytes (PCE). No mutagenic effect of the test substance was reported. The relevant negative (vehicle: corn oil) and positive (cyclophosphamide) controls were valid.

No chromosome aberration was detected in male B6C3F1 mice at doses up to 3000 mg/kg bw.

Test substance was not mutagenic.