2-methylbut-3-yn-2-ol

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:

1995-10-04 - 1995-12-07

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Guideline study (OECD)

Data source

Reference

Reference 1

Reference Type:

other company data

Title:

Unnamed

Year:

1995

Report date:

1995

Reference 2

Reference Type:

secondary source

Title:

SIDS Initial Assessment Report - 2-Methylbut-3-yn-ol

Author:

BASG AG

Year:

2002

Bibliographic source:

OECD SIDS

Reference 3

Reference Type:

secondary source

Title:

Unnamed

Year:

2000

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 474 (Mammalian Erythrocyte Micronucleus Test)

GLP compliance:

yes

Remarks:

Dept. of Toxicology, BASF AG

Type of assay:

micronucleus assay

Test material

Test material information

Constituent 1

Reference substance name:

2-methylbut-3-yn-2-ol

EC Number:

204-070-5

EC Name:

2-methylbut-3-yn-2-ol

Cas Number:

115-19-5

Molecular formula:

C5H8O

IUPAC Name:

2-methylbut-3-yn-2-ol

Details on test material:

- Name of test material (as cited in study report): Methyl-1-butyn-3-ol
- Date of manufacturing : February 8, 1994
- Test substance No.: 93/231
- Physical state: colorless to yellowish liquid
- Analytical purity: 99 .7 area%
- Lot/batch No.: Tank 7 + 8
- Storage condition of test material: room temperature

Test animals

Species:

mouse

Strain:

NMRI

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River GmbH, WIGA, D-W8741 Sulzfeld, Germany
- Weight at study initiation: about 28 g
- Assigned to test groups randomly: yes, acc. randomization plan prepared with an appropriate computer program
- Housing:individually in Makrolon cages, type M I
- Diet (e.g. ad libitum): ad libitum, standardized pelleted feed (Kliba Haltungsdiät, Klingentalmühle AG, CH-4303 Kaiseraugst, Switzerland)
- Water (e.g. ad libitum): ad libitum, drinking water
- Acclimation period: about one week in Makrolon cages, type M III, in groups of 5 separately according to sex


ENVIRONMENTAL CONDITIONS
- Temperature (°C): 20 - 24
- Humidity (%): 30 - 70
- Photoperiod (hrs dark / hrs light): 12 / 12

ANALYSIS
- The feed used in the study was assayed for chemical and microbiological contaminants.
- The drinking water is regularly assayed for chemical contaminants by the municipal authorities of Frankenthal and by the Technical Services of BASF Aktiengesellschaft as well as for the presence of germs by a contract laboratory.

Administration / exposure

Route of administration:

intraperitoneal

Vehicle:

- Vehicle(s)/solvent(s) used: water
- Amount of vehicle (if gavage or dermal): 10 ml
- Concentration of test material in vehicle: 30, 60, 120 mg/ml

Details on exposure:

PREPARATION OF DOSING SOLUTIONS:
- substance formulations were prepared immediately before administration
- The amount of substance or volume to be administered was related to the specific weight of the individual animals on the day of the experiment

Duration of treatment / exposure:

single intraperitoneal application

Frequency of treatment:

once

Post exposure period:

24 - 48 h

Doses / concentrations

Remarks:

Doses / Concentrations:
300, 600 1200 mg/kg bw
Basis:
analytical conc.

No. of animals per sex per dose:

5 for all test groups and negative controls;
2 male and 3 female for cyclophosphamide;
3 male and 2 female for vincristine

Control animals:

yes

Positive control(s):

cyclophosphamide
- Route of administration: intraperitoneally
- Doses / concentrations: 20 mg/kg bw

vincristine
- Route of administration: intraperitoneally
- Doses / concentrations: 0.15 mg/kg bw

Examinations

Tissues and cell types examined:

polychromatic and normochromatic erythrocytes of bone marrow

Details of tissue and slide preparation:

CRITERIA FOR DOSE SELECTION:
In a pretest for the determination of the acute oral toxicity deaths were observed down to a dose of 1250 mg/kg body weight. Therefore, a dose of 1200 mg/kg body weight was selected as the highest dose in the present cytogenetic study. 600 mg/kg and 300 mg/kg body weight were administered as further doses.

TREATMENT AND SAMPLING TIMES ( in addition to information in specific fields):

Test Group - Sampling time - Dose
1 - 24 h - vehicle control
2 - 48 h - vehicle control
3 - 24 h - 300 mg/kg bw
4 - 24 h - 600 mg/kg bw
5 - 24 h - 1200 mg/kg bw
6 - 48 h - 1200 mg/kg bw
7 - 24 h - 20 mg/kg bw cyclophosphamide
8 - 24 h - 0.15 mg/kg bw vincristine

DETAILS OF SLIDE PREPARATION:
The bone marrow was prepared according to the method described by SCHMID, W . (1976, 1977):
- The two femora were prepared from the animals, and all soft tissues were removed.
- After cutting off the epiphyses, the bone marrow was flushed out of the diaphysis into a centrifuge tube using a cannula filled with fetal calf serum which was at 37°C (about 2 ml/femur).
- The suspension was mixed thoroughly with a pipette, centrifuged at 1500 rpm for 5 minutes, the supernatant was removed except for a few drops, and the precipitate was resuspended.
- 1 drop of this suspension was dropped onto clean microscopic slides, using a Pasteur pipette . Smears were prepared using slides with ground edges, the preparations were dried in the air and subsequently stained.
- The slides were stained in eosin and methylene blue solution for 5 minutes, rinsed in aqua dest. and then placed in fresh aqua dest. for 2 or 3 minutes . They were finally stained in Giemsa solution for 12 minutes. After being rinsed twice in aqua dest. and clarified in xylene, the preparations were embedded in Corbit-Balsam.

METHOD OF ANALYSIS:
In general, 1000 polychromatic erythrocytes from each of the male and female animals of every test group are evaluated and investigated for micronuclei. The normochromatic erythrocytes (= normocytes), which occur, are also scored.

Evaluation criteria:

- The increase in the number of micronuclei in polychromatic erythrocytes of treated animals as compared with the solvent control group provides an index of a chromosome-breaking (clastogenic) effect or of a spindle activity of the substance tested.
- The number of micronuclei in normochromatic erythrocytes at the early sacrifice intervals represents the situation before test substance administration and may serve as a control value.
- A substance-induced increase in the number of micronuclei in normocytes may be found with an increase in the duration of the sacrifice intervals.
- Ratio of polychromatic to normochromatic erythrocytes indicates an influence of the test substance specifically on the bone marrow .

Statistics:

The number of polychromatic micronucleated erythrocytes after test substance treatment was nearly the range of the actual control value and within the historical values .

Results and discussion

Test results

Sex:

male/female

Genotoxicity:

negative

Toxicity:

no effects

Vehicle controls validity:

valid

Negative controls validity:

valid

Positive controls validity:

valid

Additional information on results:

RESULTS OF RANGE-FINDING STUDY
- Dose range: down to a dose of 1,250 mg/kg bw
- Clinical signs of toxicity in test animals: 1/4 animals died

Any other information on results incl. tables

SUMMARY TABLE (MALES + FEMALES) : Polychromatic and normochromatic erythrocytes

Test group	Interval: 24 h				Interval: 48 h
	Polychromatic erythrocytes	Normocytes / total amount polychromatic erythrocytes	Cells with micronuclei (%)		Polychromatic erythrocytes	Normocytes / total amount polychromatic erythrocytes	Cells with micronuclei (%)
Dose (mg/kg bw)			polychromatic	normochromatic			polychromatic	normochromatic
vehicle control	10000	3833	1.5	0	10000	5140	1.5	0
300	10000	4351	0.9	1.4
600	10000	3731	1.8	1.1
1200	10000	3794	1.6	0.8	10000	4672	1.1	0.6
20, cyclophosphamide	5000	2918	18.2**	1.4
0.15, vincristine	5000	3332	82.8**	3.6

Thus, the test substance 3-Methyl-l-butyn-3-ol did not lead to any increase in the rate of micronuclei. The number of normochromatic or polychromatic erythrocytes containing small micronuclei (d <= D/4) did not deviate from the solvent control value at any of the sacrifice intervals. Nor were large micronuclei (d > D/4) observed either in the negative control group or in the three dose groups of 3-Methyl-l-butyn-3-ol. No inhibition of erythropoiesis induced by the treatment of mice with 3-Methyl-l-butyn-3-ol was detected; the ratio of polychromatic to normochromatic erythrocytes was always in the same range as that of the control values in all dose groups.

CLINICAL EXAMINATIONS

- The single intraperitoneal administration of the vehicle in a volume of 10 ml/kg body weight was tolerated by all animals without any signs or symptoms.

- Doses of 300 mg/kg or 600 mg/kg body weight led to staggering about 30 minutes - 1 hour after 'test substance administration.

- In the 1,200 mg/kg group abdominal position, shallow respiration and a narcotic-like state were observed after about 30 minutes - 6 hours after treatment of the animals.

- Neither the single administration of the positive control substance cyclophosphamide in a dose of 20 mg/kg bw nor that of vincristine in a dose of 0 .15 mg/kg body weight caused any evident signs of toxicity .

Applicant's summary and conclusion

Conclusions:

Interpretation of results (migrated information): negative
Under the experimental conditions chosen here, the test substance 3-Methyl-1-butyn-3-ol has no chromosome-damaging (clastogenic) effect nor does it lead to any impairment of chromosome distribution in the course of mitosis.