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EC number: 291-454-0
CAS number: 90411-76-0
No specific information on toxicokinetic, metabolism or distribution of Nigrosin WLF in animals or in humans are available. Therefore, statements on toxicokinetics of Nigrosin WLF are based on the physico--chemical data as well as on the toxicological studies described in IUCLID within the REACH process.
No specific information on toxicokinetic, metabolism or distribution of
Nigrosin WLF in animals or in humans are available. Therefore, the
following statements on toxicokinetics of Nigrosin WLF are based on the
physico--chemical data as well as on the toxicological studies described
in IUCLID within the REACH process. The criteria outlined in the Reach
Guidance on Information Requirements and Chemical Safety Assessment,
Chapter R7c. Section R7.12: Guidance on Toxicokinetics, will be applied
throughout the statement.
The Chemical name of Nigrosin WLF is Hydrochloric acid, reaction
products with aniline and nitrobenzene, sulfonated, sodium salts. This
organic UVCB substance contains aniline as an impurity. Since the
concentration on Aniline is very low, below 0.2% (w/w), this impurity is
not further evaluated in this assumption. The molecular weight of this
black solid could not be determined. The calculated vapour pressure
values are extrapolated at 0.000005 Pa at 20 °C, 0.0000095 Pa at 25 °C
and 0.00017 Pa at 50 °C. The melting point was determined according to
the guideline "EC-A 1"and the Differential thermal analysis (DTA) showed
no melting point The boiling point was determined according to the
guideline "EC-A 2"and the Differential thermal analysis (DTA) showed no
boiling point. The sample decomposed at 310 °C. The water solubility is
100 g/liter, the log Pow is unknown.
Due to this information inhalation exposure is unlikely
The molecular weight cannot be determined but can be assumed to be >500
g and the log Pow is not known. However the substance is soluble in
water. Therefore the guidance document proposes that the substance is
likely to absorbed from GI tract. However, from the acute oral toxicity
no clinical findings are reported (LD50 >2000 mg/kg bw , Report No.
T5050442, Löser 1975) . From the available repeated oral dose toxicity
study neither hematology nor clinical chemistry gave evidence for
treatment related effects up to 1000 mg/kg bw/day . The only test item
related microscopic and macroscopic changes at terminal sacrifice are
slight grey or black discolorations in a dose-related manner in all
treated groups, predominantly in the lymph nodes and less frequently in
the intestine and /or Peyer’s patches. Corresponding to these findings
at clinical observations it was noted that the color of feces was
changed (black) in cages of treatment groups (Report No T2082697,
Schladt 2013). These observations indicate poor absorption after oral
Referring to dermal absorption, as the substance is a solid and the
molecular weight is supposed to be high ( > 500 g) and the water
solubility is 100 g/l and log Pow is unknown, therefore it is
anticipated that dermal absorption is low to moderate. The acute dermal
toxicity study (LD50 >2000 mg/kg bw, Report No. AT06430, Gillissen 2012)
as well as the skin irritation (Report No. T1048720, Mihail 1976) or the
skin sensitization study (Report No. AT06456, Vohr 2012) do not provide
information on dermal absorption because no systemic effects are
reported thus confirming the assumption-of a low absorption rate.
There are no animal experiments available using the inhalation route.
The substance is a solid with very low volatility based on vapor
pressure below 0.5 kPa and a boiling point above 150 °C (decomposition
by >300 °C), 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 the alveolar region of the respiratory tract. According to OECD
guideline 110, the particle size distribution of Hydrochloric acid,
reaction products with aniline and nitrobenzene, sulfonated, sodium
salts was determined by scanning electron microscopy method for the
sieved fraction (100 µm, 0.15 % of total sample) and presented on the
basis of calculated mass fractions. The median diameter was 78.22 µm
with the main fraction of 76 % distribution in the range of 10 - 100 µm;
and hence the tested Hydrochloric acid, reaction products with aniline
and nitrobenzene, sulfonated, sodium salts with sieved size smaller than
100 µm are mainly dominated by inhalable fraction as defined in EN 481.
Thus it is unlikely that large quantities of the compound are inhaled.
As the log Pow is unknown no statement can be given for the absorption
directly across the respiratory tract epithelium. The compound is
soluble in water (100 g/l) and may be retained within the mucous
membranes. For absorption of deposited material similar criteria as for
GI tract may apply. Based on the physico-chemical properties the
potential tor respiratory absorption is low. Taking into account the
lack of observed effects after oral ingestion it is likely that the
absorption rate via inhalation and oral dosing is low and absorption
vial inhalation is considered to be comparable to that via
There are no specific data available. The compound is soluble in water
and may be retained within the mucous. In the available repeated dose
toxicity study (Schladt 2013) neither hematology nor clinical chemistry
gave evidence for treatment related effects up to 1000 mg/kg bw/day .
Test item related microscopic and macroscopic changes observations at
terminal sacrifice were slight grey or black discolorations in a
dose-related manner in all treated groups, predominantly in the lymph
nodes and less frequently in the intestine and /or Peyer’s patches.
Corresponding to these findings at clinical observations it was noted
that the color of feces was changed (black) in cages of treatment
groups. As no other findings are noted these observations indicate the
low absorption rate and the consecutive distribution of the compound in
There are no specific investigations available. Based on the results of
the in vitro mutagenicity tests with Nigrosin WLF [Ames test (Report No.
AT06550, Nern 2012), HPRT (Harlan CCR Study No. 1469000, Harlan CCR
2012) and MNT in vitro (Report No. AT06519, Nern 2013)] it is concluded
that DNA-reactive metabolites of the substance will probabely not be
generated in mammals in the course of hepatic transformation.
There is no specific information available. However, in the sub-acute
oral study in rats at clinical observations, it was noted that the color
of feces was changed (black) in cages of treatment groups, indicating
that the compound might be mainly excreted via feces
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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