2-chlorobutane

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

Study period:

1989

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Well documented, according to accepted guidelines

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1989

Report date:

1989

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 474 (Mammalian Erythrocyte Micronucleus Test)

Version / remarks:

1983 followed, reliability scoring based on 1997 guideline.

Deviations:

no

GLP compliance:

yes

Type of assay:

micronucleus assay

Test material

Test material information

Constituent 1

Reference substance name:

Sec-butylchloride

IUPAC Name:

Sec-butylchloride

Constituent 2

Reference substance name:

76-86-4

IUPAC Name:

76-86-4

Test material form:

other: colourless liquid

Details on test material:

- Name of test material (as cited in study report): Sec-butylchloride
- Physical state: Liquid (colourless)
- Storage condition of test material: Cool, well-ventilated place

Test animals

Species:

mouse

Strain:

other: BOR:NMRI SPF (Han.)

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Firma Winkelmann, Versuchtierzucht, D- 4791 Borchen, Germany
- Age at study initiation: Adult (about 3 months)
- Weight at study initiation: 32.9 to 38.6 g (males); 30.9 to 35.0 g (females)
- Assigned to test groups randomly: Yes, by lot
- Housing: Collective caging
- Diet: Ad libitum
- Water: Ad libitum
- Acclimation period: 12 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 21.5 ± 1.5
- Humidity (%): 55 ± 10
- Photoperiod (hrs dark / hrs light): 12/12

Administration / exposure

Route of administration:

intraperitoneal

Vehicle:

- Vehicle(s)/solvent(s) used: corn oil
- Amount of vehicle (if gavage or dermal): 10 mL/kg
- Lot/batch no. (if required): Batch: 2466515
- Manufacturer: Roth GmbH, Karlsruhe

Details on exposure:

PREPARATION OF DOSING SOLUTIONS: By suspending appropriate amounts in corn oil

Duration of treatment / exposure:

Single administration

Frequency of treatment:

Single administration

Post exposure period:

24, 48, or 72 hours

Doses / concentrations

Remarks:

Doses / Concentrations:
2000 mg/kg bw
Basis:
nominal conc.

No. of animals per sex per dose:

5/sex in control groups and 15/sex in test-article groups (with 5/sex being sacrificed for smear evaluation at each time point)

Control animals:

yes, concurrent vehicle

Positive control(s):

Cyclophosphamide
- Route of administration: intraperitoneal
- Doses / concentrations: 40 mg/kg bw in 10 mL/kg corn oil
- positive control group 5 males and 5 females
- Batch No 13096473, supplied by Asta-Werke, D-4800 Bielefeld

Examinations

Tissues and cell types examined:

Bone marrow from femurs.

Details of tissue and slide preparation:

The femurs were removed and the bone marrow was suspended in fetal calf serum. Samples were centrifuged at 1.600 x g, decanted and then one drop of each single suspension was smeared on a slide by means of a second slide.

These preparations were dried, fixed in absolute (99 %) methanol for 5 min. and then allowed to air dry. The slides were stained using a May-Grünwald and Giemsa solution.

From each animal 2 preparations were made. Prior to analysis all the slides were randomized and coded (blind evaluation).

Evaluation criteria:

The test substance is considered to be active if a statistically significant increase in the number of polychromatic erythrocytes with micronuclei in comparison to the control values occurs at any point in time.

Statistics:

One factorial analysis of variance.

Results and discussion

Test results

Sex:

male/female

Genotoxicity:

negative

Toxicity:

yes

Vehicle controls validity:

valid

Negative controls validity:

not applicable

Positive controls validity:

valid

Additional information on results:

RESULTS OF RANGE-FINDING STUDY
- Dose range: 1000, 2500 and 5000 mg/kg bw
- Clinical signs of toxicity in test animals:
Animals treated with 5000 and 2500 mg/kg showed severe ataxia, a distinct writhing-reflex, a lateral body position, sedation and piloerection i.e. 5 min. p.a. and up to 4 hours p.a., whereby the lower dosed animals only showed slight ataxia, a slight sedation and a slight piloerection at this point of time. Animals treated with 1000 mg/kg were slightly sedated for about 1 hour and showed a very slight piloerection.

Any other information on results incl. tables

For animals treated with a single dose of 2000 mg/kg bw a very slightly reduced activity (sedation) and piloerection was noted 1 to 3 hours following administration, but the animals were normal in appearance and behaviour afterwards. No animal died throughout the study.

Applicant's summary and conclusion

Conclusions:

Interpretation of results (migrated information): negative
2 -chlorobutane is considered negative for mutagenicity in this in-vivo test.

Executive summary:

The number of polychromatic erythrocytes with micronuclei was significantly incresed 24h post injection in the positive control animals. This confirms the sensitivity of the animal strain used. No significant differences between animals treated with 2 -chlorobutane and control animals were noted at 24, 48 and 72 hours following application. The number of polychromatic and normochromatic erythrocytes and the ratio polychromatic/normochromatiuc erythrocytes was not significantly different to the controls in animals treated with 2 -chlorobutane at any time. Thus, 2 -chlorobutane is considered negative for mutagenicity in this test.