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EC number: 701-196-7
CAS number: -
A substance can enter the body via the gastrointestinal tract, the
lungs, or the skin, depending on the exposure route.
After oral administration, in general, a compound needs to be dissolved
before it can be taken up from the gastro-intestinal tract. GPM-800
dissolves in water (62 g/L (at 20°C), therefore it is expected to
readily dissolve into the gastrointestinal fluids. In principle, this
would allow passive diffusion (passage of small water-soluble molecules
through aqueous pores or carriage of such molecules across membranes
with the bulk passage of water). GPM-800 is a polymeric mercaptan with
a considerable size range (appr. 490-1474 g/mol). As absorption is
estimated to be still possible via this route for molecules with a
molecular weight below 1000, some uptake via passive diffusion is
expected for GPM-800. Furthermore, the substance dissolves in n-octanol,
which results in a moderate partition coefficient (log Pow > 1.2 (at
20°C)). This lipophilic characteristic favors absorption by passive
diffusion. The hydrolysis rate is slow (t1/2 > 1 year at 25°C at pH 4,
7 and 9) and is not further expected to influence the uptake. In
conclusion, its solubility in water, its moderate partition coefficient
and its molecular size will allow oral absorption. For risk assessment
purposes oral absorption of GPM-800 is therefore set at 100% . The oral
toxicity data do not provide reason to deviate from the proposed oral
absorption factor. Once absorbed, wide distribution of GPM-800
throughout the body is expected based on its water solubility and its
molecular weight range. As GPM-800 dissolves both in water and in
n-octanol, it is expected not to have a special preference for fatty
tissues. GPM-800 is expected to be excreted via urine. Based on these
facts, GPM-800 is not expected to bio-accumulate significantly in the
body upon exposure.
GPM-800 is a liquid with low volatility, as reflected in a low vapour
pressure (0.16 Pa at 20°C) and absence of a boiling point (substance
decomposes at ≥320°C). This implies that exposure via inhalation of
vapour of GPM-800 is not likely to occur. However, liquid aerosols can
be formed, which can be inhaled. Once GPM-800 reaches the lung tissue,
it will readily dissolve in the mucus lining of the respiratory tract.
The moderate lipohilicity allows the substance to cross the alveolar and
capillary membranes by passive diffusion and be absorbed. Based on the
above data, for risk assessment purposes the inhalation absorption of
GPM-800 is set at 100%.
In general, liquids such as GPM-800 are taken up more readily than dry
particulates. In order to cross the skin, a compound must first
penetrate into the stratum corneum (non-viable layer of corneocytes
forming a complex lipid membrane) and subsequently reaches the viable
epidermis, the dermis and the vascular network. The stratum corneum
provides its greatest barrier function against hydrophilic compounds,
whereas the viable epidermis is most resistant to penetration by highly
lipophilic compounds. The combined characteristics of moderate water
solubility and moderate lipophilicity of GPM-800 enables the substance
to cross both barriers. Therefore dermal absorption is likely to be
high. GPM-800 is slightly surface active, with a surface tension of 29.9
mN/m (at 20°C, at 250 mg/L). However at this value, this characteristic
is not expected to be of major influence on the uptake (only surfactants
with a surface tension < 10 mN/m are expected to greatly enhance dermal
uptake). On the other hand, the molecular size of GPM-800
(representative MW appr. 800 g/mole) is expected to hamper dermal
absorption as it may be too large for uptake across biomembranes.
According to the criteria given in the REACH Guidance, 10% dermal
absorption will be considered in case MW >500 and log Pow <-1 or >4,
otherwise 100% dermal absorption should be used. Both the molecular
weight of GPM-800 (approx. 490-1474 g/mol) and the moderate partition
coefficient do not meet the criteria for limited dermal absorption.
Therefore, for risk assessment purposes dermal absorption is set at 100%.
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.
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