Registration Dossier
Registration Dossier
Data platform availability banner - registered substances factsheets
Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.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
Use of this information is subject to copyright laws and may require the permission of the owner of the information, as described in the ECHA Legal Notice.
EC number: 213-914-1 | CAS number: 1066-40-6
- 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: oral
Administrative data
- Endpoint:
- short-term repeated dose toxicity: oral
- Type of information:
- experimental study
- Adequacy of study:
- supporting study
- Study period:
- 12-06-1989 to 12-02-1990
- Reliability:
- 2 (reliable with restrictions)
- Rationale for reliability incl. deficiencies:
- comparable to guideline study with acceptable restrictions
- Remarks:
- The restrictions were only one dose tested, only 6 animals per sex per group, no haematology or clinical chemistry evaluation, histopathology conducted after 20 years.
Data source
Referenceopen allclose all
- Reference Type:
- study report
- Title:
- Unnamed
- Year:
- 1 990
- Report date:
- 1990
- Reference Type:
- study report
- Title:
- Unnamed
- Year:
- 2 010
- Report date:
- 2010
Materials and methods
Test guideline
- Qualifier:
- equivalent or similar to guideline
- Guideline:
- OECD Guideline 407 (Repeated Dose 28-Day Oral Toxicity Study in Rodents)
- Deviations:
- yes
- Remarks:
- Only one dose tested, only 6 animals per sex per group, no haematology or clinical chemistry evaluation, histopathology conducted after 20 years
- 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:
- Hexamethyldisiloxane
- Test material form:
- other: solution
- Details on test material:
- - Name of test material (as cited in study report): Hexamethyldisiloxane
- Substance type: siloxane
- Physical state: Liquid
- Stability under test conditions: No data
- Storage condition of test material: No data
Constituent 1
Test animals
- Species:
- rat
- Strain:
- Sprague-Dawley
- Sex:
- male/female
Administration / exposure
- Route of administration:
- oral: gavage
- Vehicle:
- unchanged (no vehicle)
- Analytical verification of doses or concentrations:
- not specified
- Duration of treatment / exposure:
- 28 days
- Frequency of treatment:
- daily (5 days/week)
Doses / concentrations
- Dose / conc.:
- 1 500 mg/kg bw/day (actual dose received)
- No. of animals per sex per dose:
- SIx
- Control animals:
- yes
Results and discussion
Effect levels
- Key result
- Dose descriptor:
- LOAEL
- Effect level:
- 1 500 mg/kg bw/day (actual dose received)
- Based on:
- test mat.
- Sex:
- male/female
- Basis for effect level:
- other: Based on bile duct protoporphyrin accumulation at the the only dose tested
Target system / organ toxicity
- Critical effects observed:
- not specified
Any other information on results incl. tables
No
treatment-related deaths occurred. There were no clinical signs of
toxicity or effects on body weight gains.
Statistically significant increase in the relative kidney weights was
observed in male rats. However, no increase in liver weights was noted
in either male or female rats.
The addendum reported the following microscopic findings: Dark brown pigment was observed in bile ducts from 4/6 males. Under polarised light the pigment showed red birefringence and 'Maltese cross' patterns and was accompanied by bile duct proliferation and chronic inflammation. In the reported study the brown pigmented material had been observed, but was called bile stasis with an attendant granulomatous cholangitis. It should be noted that bile stasis is a process, not a material and that what would actually have been observed is bile pigment (bile) that was accumulated due to intra- or extra-hepatic obstruction. It does not appear that any stains were used to characterise the material (bile). In the 1990 report the authors hypothesised that the presumptive bile stasis was secondary to dosing errors, i.e. the authors' entire interpretation was erroneous and followed misidentification of the brown pigment. The amendment noted that although the pigment deposits in the old slides often appeared washed out, the classical appearance of protoporphyrin pigment (red birefringence and Maltese cross patterns under polarised light) was observed clearly enough to make a confident diagnosis.
There is ongoing research into the origin of the brown pigment found in bile ducts of some rats treated with some silicon-containing compounds.
Therefore, until this research is completed, the NOAEL/LOAEL is based on the effects on the liver, which were dismissed in 1990.
Applicant's summary and conclusion
- Conclusions:
- In a 28-day oral gavage study (DCC, 1990), conducted to GLP using a protocol with limitations compared with OECD test guidelines, the NOAEL for hexamethyldisiloxane for effects relevant to humans was less then 1500 mg/kg bw/day, based on bile duct protoporphyrin accumulation at a dose of 1500 mg/kg bw/day (the only dose tested).
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.
Reproduction or further distribution of this information may be subject to copyright protection. Use of the information without obtaining the permission from the owner(s) of the respective information might violate the rights of the owner.