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Diss Factsheets
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EC number: 451-060-3 | CAS number: 122886-55-9
- 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
Basic toxicokinetics
Administrative data
- Endpoint:
- basic toxicokinetics, other
- Remarks:
- Toxicokinetic assessment of the substance based on the available data
- Type of information:
- other: expert statement
- Adequacy of study:
- key study
- Study period:
- Not applicable
- Reliability:
- 2 (reliable with restrictions)
- Rationale for reliability incl. deficiencies:
- other: since this is a theoretical assessment, the Klimisch value cannot be 1.
Data source
Reference
- Reference Type:
- study report
- Title:
- Unnamed
- Year:
- 2 018
Materials and methods
- Objective of study:
- other: Toxicokinetic assessment of the substance based on the available data
Test guideline
- Qualifier:
- according to guideline
- Guideline:
- other: Guidance for the implementation of REACH. Guidance on information requirements and chemical safety assessment. Chapter R.7c: Endpoint specific guidance. European Chemical Agency, Version 6.0
- Version / remarks:
- November 2016
- Deviations:
- no
- GLP compliance:
- no
Results and discussion
Main ADME results
- Type:
- absorption
- Results:
- The absorption factors for risk assessment purposes are derived to be 10% (oral), 100% (inhalation) and 10% (dermal).
Any other information on results incl. tables
Toxicokinetic assessment
A toxicant can enter the body via the gastrointestinal tract, the lungs and the skin. In general, a compound needs to be dissolved before it can be taken up from the gastrointestinal tract after oral administration.
KY-UN has a very low water solubility of < 3.03 μg/L. This implies that the substance will only dissolve to a limited extend into the gastrointestinal fluids and consequently uptake via passive diffusion (passage of small water-soluble molecules through aqueous pores or carriage across membranes with the bulk passage of water) will be limited. In addition, the high molecular weight (508.74) is also not favorable for this process. KY-UN has a high partition coefficient, therefore this substance will dissolve in lipids and has the ability to cross epithelia by passive diffusion.
No data are available on the dissociation constant of KY-UN, therefore it is unclear in which state (ionized or not ionized) the substance will be present under physiological circumstances in the stomach or intestinal tracts. Since it is generally thought that ionized substances do not readily diffuse across biological membranes, the state of the substance might hamper uptake.
Considering all this data, oral absorption of KY-UN is considered to be limited due to its very low water solubility, its high molecular size, and its ability to dissolve in lipids. Therefore, for risk assessment purposes oral absorption of KY-UN is set at 10%. The oral toxicity data do not provide reasons to deviate from the proposed oral absorption factor.
The low vapour pressure (1.5E-12 Pa at 25°C) indicates that KY-UN is a substance with low volatility. Inhalation of vapour is therefore considered very limited. KY-UN is a powder, with a mean particle diameter (MMAD) of 72.6 μm, and with 50% of the particles having a diameter < 66.4 μm. In humans, particles with aerodynamic diameters below 100 μm have the potential to be inhaled. Particles with aerodynamic diameters below 50 μm may reach the thoracic region and those below 15 μm can reach the alveolar region of the respiratory tract. Based on the size of the particles, a significant part of the particles are expected to be able to reach all parts of the lung upon inhalation. If the substance reaches these regions, KY-UN is not likely to dissolve in the mucus lining of the respiratory tract and to get absorbed significantly, due to the very low water solubility. Since KY-UN is able to dissolve in lipids, some uptake through respiratory epithelium is possible. In the absence of actual data on inhalation absorption, for risk assessment purposes the inhalation absorption of KY-UN will be set at 100%.
KY-UN is a powder and as its water solubility is very low, and consequently the ability to dissolve into the surface moisture of the skin followed by uptake and partition from the stratum corneum into the epidermis will be restricted. Its ability to dissolve in lipids will favour crossing of epidermal barriers, although its high molecular size is expected to hamper uptake through dermal epithelium. According to the guidance, a default value of 100% skin absorption is generally used unless molecular weight is above 500 and log Pow is outside the range [-1, 4]. Since KY-UN has a molecular weight of 508.74 and a log Pow >6, it does meet either criteria. Therefore, the dermal absorption of KY-UN for risk assessment purposes is set at 10%.
Once absorbed, distribution of the test substance throughout the body is expected to be limited based on its very low water solubility and high molecular weight. Absorbed KY-UN is expected to be excreted mainly via bile based on its very low water solubility and high molecular weight. Based on its partition coefficient, KY-UN is expected to accumulate in adipose tissue, and therefore bioaccumulation can be expected.
Applicant's summary and conclusion
- Conclusions:
- A toxicokinetic assessment was performed based on the available data of KY-UN. Based on the physical/chemical properties of the substance, absorption factors for this substance are derived to be 10% (oral), 100% (inhalation) and 10% (dermal) for risk assessment purposes. The bioaccumulation potential is expected to be significant.
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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