Registration Dossier
Registration Dossier
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EC number: 464-320-6 | CAS number: 423772-95-6
Endpoint summary
Administrative data
Link to relevant study record(s)
Description of key information
The available evidence suggests that the substance is potentially bioavailable via the oral and dermal routes and also by inhalation if exposure occurs. The substance is expected to be metabolised by the liver and mainly excreted in urine and has no potential to bioaccumulate.
Key value for chemical safety assessment
- Bioaccumulation potential:
- no bioaccumulation potential
- Absorption rate - oral (%):
- 100
- Absorption rate - dermal (%):
- 100
- Absorption rate - inhalation (%):
- 100
Additional information
- D-Xylopyranose, oligomeric, 2-octyldodecan-1-yl xyloside, constituent with 1 D-xylopyranose unit (at 66 % (w/w), MW: 430.67 g/mol)
- D-Xylopyranose, oligomeric, 2-octyldodecan-1-yl xyloside, constituent with 2 D-xylopyranose units (at 15% (w/w), MW: 562.79 g/mol)
- D-Xylopyranose, oligomeric, 2-octyldodecan-1-yl xyloside, constituent with 3 or higher D-xylopyranose units (at 4% w/w), MW: 694.91g/mol)
- 2-octyldodecan-1-ol (at 15% w/w), MW: 298.55 g/mol)
According to section 8.1.1 of Annex X of Regulation (EC) No 1907/2006 (REACH) and R7.c guidance, in absence of toxicokinetic data on the registered substance, the toxicokinetic profile of the substance (i.e. absorption, distribution, metabolism and elimination) was derived from the relevant available information collated in the dossier. The physical chemical characteristics, the results obtained from acute, repeated-dose toxicity study on the substance, as well as information gained from genotoxicity assays were used to predict its toxicokinetic behaviour.
Structure and physical-chemical properties:
The target substance C20 APX (D-Xylopyranose, oligomeric,2-octyldodecylxylosides) is a UVCB: 70-100% - The ranges stated are referring to the sum of all carbon chain lengths of the same glycosylation state.
The typical sample contains a significant amount of free guerbet alcohol representing residues of non-reacted products. The constituents are:
The molecular weight used for NOAEL/DNEL calculations is the lowest one, i.e. 298.55 g/mol, as a worse case. It has very low volatility based on its vapour pressure (6.7x10-4Pa at 25°C). It is slightly soluble (2.3 mg/L) and not bioaccumulable. The log Kow ranging 5.51-8.63 for individual components of the substance suggests a high bioaccumulation potential but a BCF calculation based on the log of Kow showed a BCF between 66 and 159 L/kg.
Absorption:
Oral/GI absorption:
The physical chemical characteristics described above suggest that the target substance is of adequate molecular size (< 500 g/mol) to participate in endogenous absorption mechanisms within the mammalian gastrointestinal tract. The absorption may be potentiated by the ability of the substance to dissolve into gastro-intestinal fluids and hence make contact with the mucosal surface.
These hypotheses are supported by oral systemic effects observed in the 28-day repeated dose toxicity study (OECD 407) performed on the substance in rats by gavage. In this study, metabolic physiological adaptation to the substance in form of hepatocyte enlargement, centrilobular in distribution for males and centrilobular or generalised for females, was observed in relation to treatment for animal of either sex treated with 750 mg/kg/day or 150 mg/kg/day but not at 15 mg/kg/day.
The NOAEL was set to 750 mg/kg bw/day in the 28-day repeated dose toxicity study. The observation of systemic effects indicates the oral bioavailability of the substance and/or its metabolites.
In light of these data, and the lack of specific information, the target substance was assumed to be 100% bioavailable by oral route for the DNELs calculation in the purpose of human health risk assessment.
Dermal absorption:
In light of these data, and the lack of specific information on the target substance, a dermal absorption of 100% was conservatively assumed for the DNELs calculation in the purpose of human health risk assessment.
Respiratory absorption:
The potential for inhalation toxicity was not evaluated in vivo. The vapour pressure of the target substance indicated an absence of volatility and inhalability and therefore no exposure by inhalation is anticipated. Thus, at ambient temperature, no respiratory absorption is expected under normal use and handling of the substance.
Based on the result of the physico-chemical properties, toxicological properties and pattern of use, e.g. potential human exposure, it has been determined that inhalation is not anticipated to be a potential route of exposure during the normal use(s) of this material.
However, if inhalation occurs, the substance is expected to be directly absorbed across the respiratory tract epithelium by passive diffusion.
In light of these data, and the lack of specific information on respiratory absorption, the substance was conservatively assumed to be 100% bioavailable by inhalation for the DNEL calculation in the purposes of human health risk assessment.
Distribution:
Systemic distribution of the substance can be predicted from its physical chemical characteristics. Considering that the substance is highly lipophilic (log Pow >4) and slightly water soluble, it is suggested that, upon systemic absorption, the substance may be transported through the circulatory system in association with a carrier molecule such as a lipoprotein or other macromolecule. Afterwards, based on its lipophilic character, the substance will readily cross cellular barriers or will be distributed into fatty tissues with a potential to accumulate. However, the substance seems to be metabolised by the liver, probably into more soluble and excretable metabolites.
Metabolism:
The results of the the 28-day repeated dose toxicity study (OECD 407) performed in the rat with the test substance showed liver changes that are consistent with the increased metabolism associated with detoxification of a xenobiotic. This liver induction confirmed that a non-negligible part of the substance is metabolised following gastrointestinal tract absorption. The cytotoxicity observed in in vivo micronucleus test in rat, also confirmed the metabolism of the test substance in rat. The results of the in vitro gene mutation study also shows slightly lower cytitixucuty in the presence of S9 metabolising system, corresponding to signs of metabolisation and detoxification process.
Excretion:
The substance having a molecular weight mainly lower than 500 g/mol, it is expected to be mainly excreted in urine and no more than 5-10% may be excreted in bile. Any substance that is not absorbed from the gastro-intestinal tract, following oral ingestion, will be excreted in the faeces.
Following dermal exposure, highly lipophilic substances, such as the substance, that have penetrated the stratum corneum but not penetrated the viable epidermis may be sloughed off with skin cells.
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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