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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:
key study
Study period:
2000-11-27 to 2001-01-15
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: The study was conducted according to the appropriate OECD test guideline, and in compliance with GLP.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2001
Report date:
2001

Materials and methods

Test guideline
Qualifier:
according to guideline
Guideline:
OECD Guideline 474 (Mammalian Erythrocyte Micronucleus Test)
Deviations:
no
GLP compliance:
yes (incl. QA statement)
Type of assay:
micronucleus assay

Test material

Constituent 1
Reference substance name:
Triethoxy(2,4,4-trimethylpentyl)silane
EC Number:
252-558-1
EC Name:
Triethoxy(2,4,4-trimethylpentyl)silane
Cas Number:
35435-21-3
IUPAC Name:
triethoxy(2,4,4-trimethylpentyl)silane

Test animals

Species:
mouse
Strain:
NMRI
Sex:
male/female
Details on test animals or test system and environmental conditions:
TEST ANIMALS

- Source: Harlan Winkelman (D-33178, Borchen)

- Weight at study initiation: 24 - 42 g

- Assigned to test groups randomly: yes, under following basis: assigned and tail tagged by chance

- Housing: Macrolon Type III (Hereto, D-79302 Emmendingen)

- Diet (e.g. ad libitum): ad libitum

- Water (e.g. ad libitum): ad libitum

- Acclimation period: minimum of 5 days


ENVIRONMENTAL CONDITIONS

- Temperature (°C): 19 - 25 ˚c

- Humidity (%): 49.5 - 61 %

- Photoperiod (hrs dark / hrs light): 12 hrs dark / 12 hrs light


IN-LIFE DATES: From: To: 15 January 2001

Administration / exposure

Route of administration:
oral: unspecified
Vehicle:
- Vehicle(s)/solvent(s) used: CMC (carboxymethyl cellulose)

- Justification for choice of solvent/vehicle: The vehicle was chosen according to its relatively nontoxicity for the animals

- Lot/batch no. (if required): 36H0738
Details on exposure:
Route of exposure: Oral
Duration of treatment / exposure:
24 - 48 hours
Frequency of treatment:
The animals received the test item once orally.
Post exposure period:
Animals were sacrificed 24 - 48 h after treatment.
Doses / concentrations
Remarks:
Doses / Concentrations:
2000 mg/kg bw
Basis:
nominal conc.
No. of animals per sex per dose:
five
Control animals:
yes, concurrent vehicle
Positive control(s):
- cyclophosphamide

- Justification for choice of positive control(s): standard guideline positive control

- Route of administration: oral

- Doses / concentrations: 10 ml/kg bw of 0.9 % solution in 0.9 % NaCl

Examinations

Tissues and cell types examined:
Bone marrow
Details of tissue and slide preparation:
CRITERIA FOR DOSE SELECTION: limit dose

TREATMENT AND SAMPLING TIMES ( in addition to information in specific fields): no further information

DETAILS OF SLIDE PREPARATION: centrifuged cells were suspended in a thin layer of FCS and smeared on a slide. The smears were air dried and stained with May-Grunwald (Merdk, D-64293 Darmstadt) / Giemsa (Merck, D-64293 Darmstadt).

METHOD OF ANALYSIS: microscopic examination. 2000 PCE scored for incidence of polychromatic erythrocytes with micronuclei. Ratio of PCE / NCE was scored based on 1000 erythrocytes (PCE+NCE)
Evaluation criteria:
A test item is classified as mutagenic if it induces either a statistically significant dose related increase in the number of micronucleated polychromatic erythrocytes or a reproducible statistically significant positive response for at least one of the test points.
Statistics:
Micronuclei in 2000 PCE per animal were counted for each sex. NCE per 1000 PCE, Sum and Mean calculated for each sex.

Results and discussion

Test results
Sex:
male/female
Genotoxicity:
negative
Toxicity:
no effects
Vehicle controls validity:
valid
Negative controls validity:
not applicable
Positive controls validity:
valid
Additional information on results:
See table 3

RESULTS OF DEFINITIVE STUDY

- Induction of micronuclei (for Micronucleus assay): negative

- Ratio of PCE/NCE (for Micronucleus assay): see table 3. The PCE/NCE ratio was unchanged in treated animals, so there is no evidence that the test substance reached the target tissue.

- Appropriateness of dose levels and route: appropriate dose and route

- Statistical evaluation: no statistically significant induction of micronuclei occurred.

Any other information on results incl. tables

Table 3: Results of in vivo micronucleus test with Wacker BS 1701 

 

Vehicle

Control

Positive

Control

200 mg/kg

bw

1000 mg/kg

bw

2000 mg/kg

bw

2000 mg/kg

bw

Number of cells evaluated

2000

2000

2000

2000

2000

2000

Sampling time (h)

24

24

24

24

24

48

Number of erythro-cytes

normo­chromatic

NR

NR

NR

NR

NR

NR

poly­chromatic

2000

2000

2000

2000

2000

2000

polychromatic with micronuclei

7 Male

5.2 Female

70.2 Male

42.4 Female

7.6 Male

9.2 Female

8.4 Male

4.8 Female

9.4 Male

5.0 Female

7.4 Male

4.8 Female

Ratio of erythro­cytes

polychromatic / normochromatic

Male

1000/679.4

Female

1000/766.6

Male

1000/608

Female

1000/657.6

Male

1000/712.4

Female

1000/655.8

Male

1000/656.4

Female

1000/611.6

Male

1000/657

Female

1000/641.2

Male

1000/1064.6

Female

1000/511

polychromatic with micro­nuclei / normochromatic

NR

NR

NR

NR

NR

NR

 

Applicant's summary and conclusion

Conclusions:
Interpretation of results (migrated information): negative
Triethoxy(2,4,4-trimethylpentyl)silane has been tested in a valid and reliable in vivo mouse micronucleus assay according to OECD 474 and under GLP. It was not genotoxic under the conditions of the test. The PCE / NCE ratio was only slightly affected in treated males, indicating that the test item had no or only slight toxic properties.