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EC number: 208-765-4 | CAS number: 541-05-9
- Life Cycle description
- Uses advised against
- Endpoint summary
- Appearance / physical state / colour
- Melting point / freezing point
- Boiling point
- Density
- Particle size distribution (Granulometry)
- Vapour pressure
- Partition coefficient
- Water solubility
- Solubility in organic solvents / fat solubility
- Surface tension
- Flash point
- Auto flammability
- Flammability
- Explosiveness
- Oxidising properties
- Oxidation reduction potential
- Stability in organic solvents and identity of relevant degradation products
- Storage stability and reactivity towards container material
- Stability: thermal, sunlight, metals
- pH
- Dissociation constant
- Viscosity
- Additional physico-chemical information
- Additional physico-chemical properties of nanomaterials
- Nanomaterial agglomeration / aggregation
- Nanomaterial crystalline phase
- Nanomaterial crystallite and grain size
- Nanomaterial aspect ratio / shape
- Nanomaterial specific surface area
- Nanomaterial Zeta potential
- Nanomaterial surface chemistry
- Nanomaterial dustiness
- Nanomaterial porosity
- Nanomaterial pour density
- Nanomaterial photocatalytic activity
- Nanomaterial radical formation potential
- Nanomaterial catalytic activity
- Endpoint summary
- Stability
- Biodegradation
- Bioaccumulation
- Transport and distribution
- Environmental data
- Additional information on environmental fate and behaviour
- Ecotoxicological Summary
- Aquatic toxicity
- Endpoint summary
- Short-term toxicity to fish
- Long-term toxicity to fish
- Short-term toxicity to aquatic invertebrates
- Long-term toxicity to aquatic invertebrates
- Toxicity to aquatic algae and cyanobacteria
- Toxicity to aquatic plants other than algae
- Toxicity to microorganisms
- Endocrine disrupter testing in aquatic vertebrates – in vivo
- Toxicity to other aquatic organisms
- Sediment toxicity
- Terrestrial toxicity
- Biological effects monitoring
- Biotransformation and kinetics
- Additional ecotoxological information
- Toxicological Summary
- Toxicokinetics, metabolism and distribution
- Acute Toxicity
- Irritation / corrosion
- Sensitisation
- Repeated dose toxicity
- Genetic toxicity
- Carcinogenicity
- Toxicity to reproduction
- Specific investigations
- Exposure related observations in humans
- Toxic effects on livestock and pets
- Additional toxicological data
Genetic toxicity: in vivo
Administrative data
- Endpoint:
- in vivo mammalian somatic cell study: cytogenicity / bone marrow chromosome aberration
- Type of information:
- experimental study
- Adequacy of study:
- key study
- Study period:
- 1980-11-25 to 1981-03-23
- Reliability:
- 2 (reliable with restrictions)
- Rationale for reliability incl. deficiencies:
- comparable to guideline study with acceptable restrictions
Data source
Reference
- Reference Type:
- study report
- Title:
- Unnamed
- Year:
- 1 982
- Report date:
- 1982
Materials and methods
Test guideline
- Qualifier:
- equivalent or similar to guideline
- Guideline:
- OECD Guideline 475 (Mammalian Bone Marrow Chromosome Aberration Test)
- Deviations:
- yes
- Remarks:
- number of cells scored for MI; presentation of results
- Principles of method if other than guideline:
- Method: other
- GLP compliance:
- yes
- Type of assay:
- chromosome aberration assay
Test material
- Reference substance name:
- Hexamethylcyclotrisiloxane
- EC Number:
- 208-765-4
- EC Name:
- Hexamethylcyclotrisiloxane
- Cas Number:
- 541-05-9
- Molecular formula:
- C6H18O3Si3
- IUPAC Name:
- hexamethyl-1,3,5,2,4,6-trioxatrisilinane
Constituent 1
Test animals
- Species:
- rat
- Strain:
- Sprague-Dawley
- Sex:
- male
- Details on test animals or test system and environmental conditions:
- TEST ANIMALS
- Source: Charles River
- Age at study initiation: 50-60 days
- Weight at study initiation: 200-440 g
- Assigned to test groups randomly: [no/yes, under following basis: ]
- Fasting period before study:
- Housing: 6/cage
- Diet: ad libitum
- Water: ad libitum
- Acclimation period:
ENVIRONMENTAL CONDITIONS
- Temperature (°C): 20
- Humidity (%): 50
- Air changes (per hr): no information
- Photoperiod (hrs dark / hrs light): 12/12
Administration / exposure
- Route of administration:
- intraperitoneal
- Vehicle:
- Vehicle: DMSO
- Duration of treatment / exposure:
- 6, 24 or 48 hours
- Frequency of treatment:
- Single ip injection of test and positive and solvent controls
Doses / concentrationsopen allclose all
- Dose / conc.:
- 125 mg/kg bw (total dose)
- Dose / conc.:
- 225 mg/kg bw (total dose)
- Dose / conc.:
- 300 mg/kg bw (total dose)
- Dose / conc.:
- 400 mg/kg bw (total dose)
- Dose / conc.:
- 515 mg/kg bw (total dose)
- Dose / conc.:
- 1 080 mg/kg bw (total dose)
- No. of animals per sex per dose:
- 5 male animals per dose
- Control animals:
- yes, concurrent vehicle
- Positive control(s):
- -cyclophosphamide
- Justification for choice of positive control(s): none given in report
- Route of administration: ip injection
- Doses / concentrations: 21 mg/kg bw
Examinations
- Tissues and cell types examined:
- Bone marrow
- Details of tissue and slide preparation:
- CRITERIA FOR DOSE SELECTION: initial cytotoxicity assay.
The doses used in the cytogenetic studies were based on the range-finding experiments. Animals were injected IP with hexamethylcyclotrisiloxane prepared in glass tubes at doses of 1081, 721, 360, 180, and 72 mg/kg. No deaths were observed. A second range-finding experiment was not performed. All subsequent cytogenetic studies were performed using polypropylene tubes to prepare samples.
TREATMENT AND SAMPLING TIMES ( in addition to information in specific fields): Animals were sacrificed at 6, 24, or 48 hours after injection. Colchicine was injected 2 to 2.5 hours before sacrifice at a final dose of approximately 1.5 mg/kg.
DETAILS OF SLIDE PREPARATION: Approximately four slides were prepared from each animal. Slides were fixed, stained with Giesma and permanently mounted.
METHOD OF ANALYSIS: Suitable cells (with properly condensed and well spread chromosomes) were photographed. Projected photographs were examined for chromosomal breaks or gaps, chromatid breaks or gaps, complex rearrangements, polyploidy and large translocation or deletions. Small translocation or deletions could not be detected. - Statistics:
- If the compound did not cause chromosomal damage, then the distribution of breaks per animal for all the negative control and test animals is expected to follow the Poisson distribution. A comparison of the expected and observed distribution values was performed using the Chi2 test as a measure of "goodness to fit". The Wilcoxon test was used as a non-parametric test to compare the distribution of breaks per animal between the negative control animals and the highest test doses. Details of both statistical evaluations are given in the text, Statistical Methods, Snedecor, G.W. and Cochran, W.G., Iowa State University Press, Ames, Iowa, 1980.
Results and discussion
Test results
- Sex:
- male
- Genotoxicity:
- negative
- Toxicity:
- no effects
- Remarks:
- on mitotic index. Deaths occurred at highest dose.
- Vehicle controls validity:
- valid
- Negative controls validity:
- not applicable
- Positive controls validity:
- valid
- Additional information on results:
- For the cytogenetic experiments, hexamthylcyclotrisiloxane prepared in polypropylene tubes produced mortalities at high dose levels. The dosage groups analyzed in the cytogenetic studies were based on the maximum tolerated dose for each sacrifice group. In the 48-hour sacrifice group, doses of 1080 mg/kg killed 5 of 6 animals and 515 mg/kg killed 1 of 6 animals. In the 24-hour group, the highest dose level (400 mg/kg) killed 3 of 6 animals, but all 6 animals injected with 300 mg/kg lived. In the 6-hour assay, all of the animals injected with the highest dose, 300 mg/kg, lived.
There was no evidence that hexamethylcyclotrisiloxane induced chromosomal damage in rats following IP injection. A summary of the total number of cells analyzed for each dose at each time of sacrifice is summarized as follows: For animals injected with 125 mg/kg the frequencies of breaks were 1.40%, 2.02%, and 1.99% for the three times of sacrifice (6, 24, and 48 hours, respectively); frequencies of 0.71%, 2.17%, and 2.35% were seen for animals injected with 225 mg/kg at the three times of sacrifice. For animals dosed with 300 mg/kg, the frequencies of breaks were 2.07% and 1.01% at 6 and 24 hours; 0.90% breaks were seen with animals dosed with 400 mg/kg at 24 hours; and 1.94% breaks were seen in animals injected with 515 mg/kg at 48 hours. No complex rearrangements such as quadriradials, triradials, or ring chromosomes were detected in animals injected with the test substance. For the negative control animals, the frequencies of breaks were 0.85%, 0.58%, and 2.23% for sacrifice times of 6, 24, and 48 hours, respectively. The animals injected with cyclophosphamide had both a large number of breaks and complex rearrangements. A comparison of the frequencies of breaks for doses of hexamethylcyclotrisiloxane with the negative control at the three time points shows no significant differences. These frequencies are similar to those recorded for control animals in previous testing. The frequency of breaks in previous negative control animals ranged from 0 to 2.58%, a range compatible with all the results obtained in this project. The conclusion based on comparison to historical data is confirmed by a statistical analysis using the Wilcoxon test that demonstrated that there was no difference between the number of breaks per animal for the negative control groups and the test groups. The use of the Chi2 test as a measure of "goodness to fit" indicated that the distribution of breaks per animal did not closely follow the Poisson distribution. However, the Wilcoxon test demonstrated that there was no difference between the number of breaks per animal for the negative control groups and the test groups.
Any other information on results incl. tables
Data for the following dose groups is summarized below:
a. 48-hour sacrifice time: 515, 225, and 125 mg/kg
b. 24-hour sacrifice time: 400, 300, 225, and 125 mg/kg
c. 6-hour sacrifice time: 300, 225, and 125 mg/kg
Summary of Chromosome Aberration Data at three respective
intervals
Test Dose No.
Chem. (mg/kg) cells G* B* O* MI*(%)
DMSO:
6 hrs -- 142 1 1 0 4.6
101 0 2 0 5.4
116 5 1 0 5.8
120 1 1 0 7.3
107 0 0 0 4.7
24 hrs* -- 120 0 0 0 7.3
101 2 0 0 3.7
103 1 2 0 3.0
95 0 1 0 2.7
94 0 0 0 6.8
48 hrs -- 117 0 0 0 4.8
108 1 3 0 5.7
92 0 5 0 3.5
113 2 4 0 7.4
107 0 0 0 5.2
Test material:
6 hrs 300 112 0 3 0 3.7
120 1 1 0 4.8
113 0 3 0 4.3
115 0 0 0 3.4
120 0 5 0 3.5
225 114 3 0 0 6.9
108 0 1 0 4.9
120 0 0 0 3.3
109 1 3 0 2.9
110 2 3 0 4.6
125 98 1 1 0 6.6
107 2 1 0 7.9
106 2 1 0 4.9
118 2 3 0 3.6
24 hrs 400 117 0 1 0 4.9
106 3 1 0 5.9
300 121 0 2 0 3.0
115 0 0 0 9.9
136 3 0 0 5.1
108 3 1 0 7.9
114 4 3 0 5.0
225 104 0 1 0 10.0
119 0 0 0 8.3
115 0 4 0 5.8
138 0 3 0 7.8
122 1 5 0 8.9
125 113 0 0 0 7.7
121 0 2 0 7.8
110 0 0 0 4.4
131 0 6 0 5.1
119 0 4 0 6.0
48 hrs 515 106 3 4 0 9.9
109 0 0 0 6.7
146 2 3 0 12.4
225 102 1 3 0 6.4
115 0 3 0 6.1
109 0 3 0 9.3
109 0 0 0 6.8
103 0 1 0 6.4
100 0 5 0 5.4
125 112 0 3 0 9.5
119 1 4 0 6.9
43 0 0 0 5.0
118 0 2 0 5.1
111 0 1 0 3.1
Cyclophosphamide
24 hrs 21 109 ND >64 7Quad 4.2
3Tri
120 ND >67 2Quad 5.4
1Tri
107 ND >48 2Quad 2.5
2Tri
---
*: G=Gaps; B=Breaks; O=Other; MI=Mitotic Index
ND = not determined
Quad = quadriradial
Tri = Triradial
Applicant's summary and conclusion
Information on Registered Substances comes from registration dossiers which have been assigned a registration number. The assignment of a registration number does however not guarantee that the information in the dossier is correct or that the dossier is compliant with Regulation (EC) No 1907/2006 (the REACH Regulation). This information has not been reviewed or verified by the Agency or any other authority. The content is subject to change without prior notice.
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