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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.

The new ECHA CHEM database has been released by ECHA, and it now contains all REACH registration data. There are more details on the transition of ECHA's published data to ECHA CHEM here.

Diss Factsheets

Administrative data

Endpoint:
in vivo mammalian somatic cell study: cytogenicity / erythrocyte micronucleus
Remarks:
Type of genotoxicity: chromosome aberration
Type of information:
migrated information: read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
weight of evidence
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Well described study and suitable for assessment.

Data source

Referenceopen allclose all

Reference Type:
secondary source
Title:
Unnamed
Year:
1995
Reference Type:
other: Publication; reference for detailed protocol
Title:
The in Vivo Erythrocyte Micronucleus Test: Measurement at Steady State Increases Assay Efficency and Permits Integration with Toxicity Studies
Author:
MacGregor JT, Wehr CM, Henika PR, Shelby MD
Year:
1990
Bibliographic source:
Fundamental and Applied Toxicology, volume 14, pages 513 - 522

Materials and methods

Principles of method if other than guideline:
Peripheral blood samples were obtained from male and female B6C3Fl mice at the end of the 13-week drinking-water toxicity study. Smears were prepared, fixed, and stained. The frequency of micronuclei in 10,000 normochromatic erythrocytes (NCB) in up to 10 animals per dose group was determined.
GLP compliance:
yes
Type of assay:
micronucleus assay

Test material

Constituent 1
Chemical structure
Reference substance name:
2-methylpropan-2-ol
EC Number:
200-889-7
EC Name:
2-methylpropan-2-ol
Cas Number:
75-65-0
Molecular formula:
C4H10O
IUPAC Name:
2-methylpropan-2-ol
Test material form:
other: colorless liquid
Details on test material:
- Name of test material (as cited in study report): t-butyl alcohol
- Physical state: clear colorless liquid
- Analytical purity: > 99 %
- Lot/batch No.: F112784
- Stability: bulk chemical is stable for 2 weeks
- Stability under test conditions: The stability of the dose formulations was at least 3 weeks at room temperature when stored in the dark and at least 3 days at room temperature under normal room light.
- Storage condition of test material: it should be protected from light at temperatures up to 60 °C

Test animals

Species:
mouse
Strain:
B6C3F1
Sex:
male/female
Details on test animals or test system and environmental conditions:
TEST ANIMALS
- Source: Frederick Cancer Research Facility
- Age at study initiation: approximately 6 weeks old
- Housing: single housing
- Diet (e.g. ad libitum): NIH-07 open formula rodent feed; ad libitum
- Water (e.g. ad libitum): deionized water; ad libitum
- Acclimation period/quarantine: 13 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 12-30 °C
- Humidity (%): 31-56 %
- Air changes (per hr): 10/hour
- Photoperiod (hrs dark / hrs light): 12/12

Administration / exposure

Route of administration:
oral: drinking water
Vehicle:
- Vehicle(s)/solvent(s) used: water

Details on exposure:
REPARATION OF DOSING SOLUTIONS: T-butyl alcohol was mixed with deionized water
Duration of treatment / exposure:
13 weeks
Frequency of treatment:
94-95 consecutive days in the drinking water
Doses / concentrations
Remarks:
Doses / Concentrations:
0, 2.5, 5, 10, 20 or 40 mg/mL in deionized
Basis:
nominal in water
No. of animals per sex per dose:
Male:
0: 8
2.5 mg/mL: 10
5 mg/mL: 10
10 mg/mL: 9
20 mg/mL: 9
40 mg/mL: 3

Female:
0: 9
2.5 mg/mL: 8
5 mg/mL: 10
10 mg/mL: 10
20 mg/mL: 9
40 mg/mL: 5
Control animals:
yes, concurrent vehicle
Positive control(s):
- used positive control: Urethane
- Doses / concentrations: 2,000 ppm

Examinations

Tissues and cell types examined:
Normochromatic erythrocytes
Details of tissue and slide preparation:
DETAILS OF SLIDE PREPARATION: Smears were prepared and fixed in absolute methanol, stained with a chromatin-specific fluorescent dye mixture of Hoechst 33258/pyronin Y, and coded.

METHOD OF ANALYSIS: Slides were scanned at 630x or 1,000x magnification using a semi-automated image analysis system to determine the micronuclei in 10,000 normochromatic erythrocytes (NCB).
A detailled discussion of this assay can be found in MacGregor et al., 1990.

Results and discussion

Test results
Sex:
male/female
Genotoxicity:
negative
Toxicity:
not specified
Vehicle controls validity:
valid
Negative controls validity:
not specified
Positive controls validity:
valid
Additional information on results:
RESULTS OF DEFINITIVE STUDY
- Induction of micronuclei (for Micronucleus assay): No increase in the frequency of micronucleated NCEs was observed. No effect on the percentage of PCEs was noted.

Any other information on results incl. tables

Males

Dose (mg/mL)

Micronucleated NCE cells (%)

PCE (%)

Number of Mice

 

0

0.09 +/- 0.01

0.86 +/- 0.14

8

 

2.5

0.10 +/- 0.01

1.03 +/- 0.07

10

 

5

0.07 +/- 0.01

0.92 +/- 0.16

10

 

10

0.09 +/- 0.02

0.68 +/- 0.08

9

 

20

0.08 +/- 0.01

0.87 +/- 0.10

9

 

40

0.06 +/- 0.03

0.52 +/- 0.25

3

 

 

 

 

 

Urethane

2

1.95 +/- 0.07

1.79 +/- 0.07

3

 

 

 

 

 

Females

Dose (mg/mL)

Micronucleated NCE cells (%)

PCE (%)

Number of Mice

 

0

0.06 +/- 0.01

0.88 +/- 0.13

9

 

2.5

0.04 +/- 0.01

0.68 +/- 0.10

8

 

5

0.05 +/- 0.01

0.77 +/- 0.16

10

 

10

0.05 +/- 0.01

0.88 +/- 0.09

10

 

20

0.07 +/- 0.01

0.94 +/- 0.08

9

 

40

0.07 +/- 0.01

0.81 +/- 0.18

5

Table 3: Frequency of Micronuclei in Mouse Peripheral Blood Erythrocytes Following Treatment with t-Butyl Alcohol in Drinking Water for 13 Weeks.

Applicant's summary and conclusion