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EC number: 203-492-7 | CAS number: 107-46-0
- 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
Repeated dose toxicity: dermal
Administrative data
- Endpoint:
- short-term repeated dose toxicity: dermal
- Type of information:
- experimental study
- Adequacy of study:
- key study
- Study period:
- 08.11.1991 to 12.12.1991
- Reliability:
- 1 (reliable without restriction)
- Rationale for reliability incl. deficiencies:
- comparable to guideline study
Cross-reference
- Reason / purpose for cross-reference:
- reference to other study
Data source
Reference
- Reference Type:
- study report
- Title:
- Unnamed
- Year:
- 1 993
- Report date:
- 1993
Materials and methods
Test guideline
- Qualifier:
- equivalent or similar to guideline
- Guideline:
- OECD Guideline 410 (Repeated Dose Dermal Toxicity: 21/28-Day Study)
- Deviations:
- yes
- Remarks:
- No urinalysis
- GLP compliance:
- yes
- Limit test:
- no
Test material
- Reference substance name:
- Hexamethyldisiloxane
- EC Number:
- 203-492-7
- EC Name:
- Hexamethyldisiloxane
- Cas Number:
- 107-46-0
- Molecular formula:
- C6H18OSi2
- IUPAC Name:
- trimethyl[(trimethylsilyl)oxy]silane
Constituent 1
Test animals
- Species:
- rat
- Strain:
- Sprague-Dawley
- Sex:
- male/female
- Details on test animals or test system and environmental conditions:
- TEST ANIMALS
- Source: Charles River Breeding Laboratories, Portage, MI
- Age at study initiation: Approximately 8 weeks
- Weight at study initiation: Males: 229-262 g; Females: 206-241 g
- Fasting period before study: No
- Housing: Individually in standard stainless steel wire cages
- Diet (e.g. ad libitum): Ad libitum
- Water (e.g. ad libitum): Ad libitum
- Acclimation period: Seven days
ENVIRONMENTAL CONDITIONS
- Temperature (°F): 68-73
- Humidity (%): 30-70
- Air changes (per hr): No data
- Photoperiod (hrs dark / hrs light): 12/12
IN-LIFE DATES: From: 13.11.1991 To: 12.12.1991
Administration / exposure
- Type of coverage:
- occlusive
- Vehicle:
- unchanged (no vehicle)
- Details on exposure:
- TEST SITE
- Area of exposure: Dorsal
- % coverage: 10 %
- Type of wrap if used: Plastic wrap and cloth bandage
- Time intervals for shavings or clipplings: as needed
REMOVAL OF TEST SUBSTANCE
- Washing (if done): yes, with a wet gauze
- Time after start of exposure: Six hours
TEST MATERIAL
- Amount(s) applied (volume or weight with unit):
- Concentration (if solution):
- Constant volume or concentration used: yes/no
- For solids, paste formed: yes/no
USE OF RESTRAINERS FOR PREVENTING INGESTION: no, not required with wrap used. - Analytical verification of doses or concentrations:
- no
- Duration of treatment / exposure:
- 28 Days
- Frequency of treatment:
- 6 hours per day, 5 days per week for a period of 28 days
Doses / concentrationsopen allclose all
- Dose / conc.:
- 100 mg/kg bw/day
- Dose / conc.:
- 500 mg/kg bw/day
- Dose / conc.:
- 1 000 mg/kg bw/day
- No. of animals per sex per dose:
- Ten
- Control animals:
- other: yes, wrapped without test substance
- Details on study design:
- - Dose selection rationale: No data
- Rationale for animal assignment (if not random): Random
- Rationale for selecting satellite groups: No satellite groups
- Post-exposure recovery period in satellite groups: No post-exposure period - Positive control:
- None
Examinations
- Observations and examinations performed and frequency:
- CAGE SIDE OBSERVATIONS: Yes
- Time schedule: Twice daily on weekdays for general appearance, behavioral abnormalities, signs of toxicity and mortality.
DETAILED CLINICAL OBSERVATIONS: No
DERMAL IRRITATION: Yes
BODY WEIGHT: Yes
- Time schedule for examinations: On the initial day of the study, weekly during the study period and just prior to necropsy.
FOOD CONSUMPTION:
- Food consumption for each animal determined and mean daily diet consumption calculated as g food/kg body weight/day: No data. Food consumption was measured weekly throughout the study period.
FOOD EFFICIENCY:
- Body weight gain in kg/food consumption in kg per unit time X 100 calculated as time-weighted averages from the consumption and body weight gain data: No
WATER CONSUMPTION: No
OPHTHALMOSCOPIC EXAMINATION: No
HAEMATOLOGY: Yes
- Time schedule for collection of blood: At study termination
- Anaesthetic used for blood collection: Yes (ketamine HCl)
- Animals fasted: Yes, for 16 hours
- How many animals: All
- Parameters checked in table No.1 were examined.
CLINICAL CHEMISTRY: Yes
- Time schedule for collection of blood: At termination of the study
- Animals fasted: Yes, for 16 hours
- How many animals: All
- Parameters checked in table No.1 were examined.
URINALYSIS: No
NEUROBEHAVIOURAL EXAMINATION: No - Sacrifice and pathology:
- See Table 2. Organs examined at necropsy (macroscopic and microscopic): At the end of dosing a complete necropsy was performed on all animals. The liver, kidneys, adrenals brain, spleen, ovaries and testes were examined and weighed. A complete set of organs/tissues were collected and retained in 10% buffered formalin. All tissues from the control and high dose groups were processed and examined microscopically.
- Other examinations:
- None reported.
- Statistics:
- Statistical Methods: Data was evaluated by two-sided Welch Trend Test. All follow-up tests were one-sided and in the same direction as the overall trend. P<0.05 was used as a critical level of significance.
Results and discussion
Results of examinations
- Clinical signs:
- no effects observed
- Dermal irritation:
- no effects observed
- Mortality:
- no mortality observed
- Body weight and weight changes:
- effects observed, treatment-related
- Food consumption and compound intake (if feeding study):
- effects observed, treatment-related
- Food efficiency:
- not examined
- Water consumption and compound intake (if drinking water study):
- not examined
- Ophthalmological findings:
- not examined
- Haematological findings:
- no effects observed
- Clinical biochemistry findings:
- no effects observed
- Urinalysis findings:
- not examined
- Behaviour (functional findings):
- not examined
- Organ weight findings including organ / body weight ratios:
- effects observed, treatment-related
- Gross pathological findings:
- no effects observed
- Histopathological findings: non-neoplastic:
- no effects observed
- Histopathological findings: neoplastic:
- not examined
- Details on results:
- CLINICAL SIGNS AND MORTALITY: No deaths, overt signs of toxicity or changes in any of the control or treated animals.
BODY WEIGHT AND WEIGHT GAIN: A slight but statistically significant decrease in body weight gains was observed in the high dose males during the last week of the study.
FOOD CONSUMPTION: A slight but statistically significant decrease in food consumption was observed in the high dose males during the last week of the study.
HAEMATOLOGY: No adverse changes occurred.
CLINICAL CHEMISTRY: No adverse changes occurred.
ORGAN WEIGHTS: A statistically significant decrease in liver and kidney weights were noted in the high dose males when expressed as organ to brain weight ratio.
GROSS PATHOLOGY: No adverse findings.
HISTOPATHOLOGY: Histopathology of organs and tissues for control and high dose group animals revealed no effects attributable to test material treatment.
Effect levels
open allclose all
- Dose descriptor:
- NOAEL
- Remarks:
- relevant to human
- Effect level:
- >= 1 000 mg/kg bw/day
- Sex:
- male/female
- Basis for effect level:
- other: No adverse effects relevant to humans.
- Dose descriptor:
- NOAEL
- Remarks:
- rats
- Effect level:
- >= 1 000 mg/kg bw/day
- Sex:
- male/female
- Basis for effect level:
- other: No adverse effects.
Target system / organ toxicity
- Critical effects observed:
- not specified
Applicant's summary and conclusion
- Conclusions:
- In a 28-day repeated dose dermal toxicity study in rats, conducted using a protocol similar to OECD 410, and to GLP, the NOEL for hexamethyldisiloxane was considered to be 500 mg/kg/day, based on reduced kidney and liver weights in males. There were no such effects in females. Overall, the NOAEL was considered to be ≥1000 mg/kg bw/day for human relevant effects. The effects on kidney and liver weights were not accompanied by histopathological findings and were not observed in females, therefore are not considered adverse.
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