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EC number: 273-227-8
CAS number: 68953-84-4
1,4-Benzenediamine, N,N'-mixed Ph and tolyl derivs. induces changes in organ weights, blood serum and haematologic parameters upon repeated oral exposure of rats. Some evidence of macrocytic anemia was demonstrated. Evaluation of the test results leads to a NOAEL of 16.00 mg/kg bw/day.
Three repeated dose oral toxicity studies in Fisher 344 rats are
available for assessment: a 3-week oral gavage study (Iatropoulos,
1994b), a 4-week dietary study (Iatropoulos, 1994a) and a 52-week
chronic dietary study (Iatropoulos, 1996). All of these repeated dose
toxicity studies were conducted according to GLP and international
standards and they are leading to similar conclusions. Out of these
studies, the 52-week chronic feeding toxicity study with a 38-week
interim sacrifice and a 12-week recovery period (Iatropoulos, 1996) was
chosen as the key study. It provides data to comprehensively assess the
long-term effects of 1,4-Benzenediamine, N,N'-mixed Ph and tolyl derivs.
The dietary levels of 53; 310 and 1900 ppm were chosen based upon the
results of the 4-week dietary study, and corresponded with mean (male
and female) ingested concentrations of 2.65; 16.00 and 100.20 mg/kg
bw/day on an average basis.
Effects observed during the 52-week study included haematological
changes, changes in the blood serum and elevated organ weights. A
proliferative activity towards urinary bladder epithelium was also
suggested. The clinical chemistry assessments showed elevated levels of
cholesterol in the serum of high dose males and females, but these
changes did not persist throughout the observation period. Increased
bilirubin levels were found in high dose males, whereas high dose
females showed decreased bilirubin levels. However, both deviations
reversed during the 12-week recovery period. Elevated organ weights for
e.g. liver, kidney and spleen were found in the mid and high dose
animals. The histopathologic examination at week 52 showed that the
spleen and liver exhibited signs of extramedullary erythropoiesis in the
high dose male and female groups. Hematologic changes included elevated
mean corpuscular volumes and decreased mean corpuscular hemoglobin in
high dose males and females. These findings suggest a macrocytic anemia
in the high dose animals. Based on these observations, an NOAEL of 16.00
mg/kg bw/day was established for 1,4-benzenediamine, N,N’-mixed Ph and
The results of the supporting 3-week oral gavage (Iatropoulos, 1994b)
and the 4-week dietary studies (Iatropoulos, 1994a) are in good
agreement with the observations described above. The 3-week oral gavage
study revealed the test chemical to have target activity towards the
liver in that an increase in organ weight plus evidence of proliferative
changes in the liver were observed. Oral gavage daily dosing of test
chemical at 3000 mg/kg bw/day to rats of both sexes led to 100%
mortality within 10 days. The 1000 mg/kg bw dose was lethal to all males
by day 7, but only to 6 of 10 females through 21 days. Lower doses (100
and 300 mg/kg day) were not lethal but did induce increased liver
weights and signs of proliferative changes within the liver and possibly
the urinary bladder. Only the lowest dose was without an effect on body
The 4-week toxicity study was conducted by adding 120; 470 and 1900 ppm
of test substance to the animals’ diet, which corresponds to actual
ingested doses of 7.5, 30 and 120 mg/kg bw/day. Macrocytic anemia was
the primary change in rats related to chemical exposure. These changes
were reversible within 2 weeks following dietary exposure cessation, as
were liver weight and serum cholesterol elevations. These changes were
minor and were associated with no apparent prolonged adverse effects.
The PCNA data for liver and bladder indicated increased cellular
division at the higher doses, but with a lack of dose-responsiveness.
Based upon these findings, the NOAEL for 1,4-benzenediamine, N,N’-mixed
Ph and tolyl derivs. in rats is 470 ppm in the diet, corresponding to
30mg/kg bw/day. As this NOAEL is above the NOAEL derived from the
52-week study, the latter is retained in the calculations of the DNELs.
No dermal or inhalation repeated dose toxicity studies are available.
According to section R.188.8.131.52 of ECHA’s Guidance on information
requirements and chemical safety assessment, new repeated dose toxicity
testing is only required, as a last resort, if route-to-route
extrapolation starting from the available repeated dose data is not
The available set of test results for 1,4-Benzenediamine, N,N'-mixed Ph
and tolyl derivs. - including a 52-week dietary exposure study and
toxicokinetic examinations of both oral and dermal absorption of main
constituent(s) of the test substance – does allow oral-to-dermal
extrapolation of the chronic oral repeated dose study results towards
the relevant DNEL long-term for dermal route-systemic, and as a
consequence, no additional dermal repeated dose toxicity study was
The multi-constituent substance 1,4-Benzenediamine, N,N'-mixed Ph and
tolyl derivs. has a very low vapour pressure (see vapour pressure
section) and virtually no particles < 100 um are detected upon
granulometric sieving experiment (see granulometry section). Moreover,
the supported uses and exposure scenarios show negligible exposure to
humans via the inhalatory route. As a consequence, exposure of humans
via inhalation is not likely and testing of the repeated dose toxicity
via inhalation is not appropriate.
Three repeated dose oral toxicity studies with rats are available for
assessment: a 3-week oral gavage study, a 4-week dietary study and a
52-week chronic dietary study. However, the 3-week study was performed
as a range-finding study and the observations made were not of
sufficient detail to allow a STOT-RE analysis. As a consequence, only
the 4- and 52-week studies were used to assess the STOT-RE properties of
1,4-Benzenediamine, N,N'-mixed Ph and tolyl derivs..
Both the 4- and the 52-week studies showed evidence of changes in organ
(liver) weights and macrocytic anemia. In both cases, all changes had
minor impact on animal health status, and none were life threatening.
The change in liver weight was reversible and was not associated with
histopathological changes or liver dysfunction; so the repeated exposure
to the substance does not cause serious damage to the organism. The
effect of macrocytic anemia was reversible and had a minor impact on
animal health. Because of its minimal toxicological importance this
effect does not warrant a STOT-RE classification.
As a consequence, it can be concluded that no classification according
to CLP Regulation (EC) No. 1272/2008 regarding STOT-RE properties is
warranted. Likewise, comparison of the severity of the experimentally
observed effects with the criteria described in section 3.2.4 of Annex
VI of Directive 67/548/EEC (Dangerous Substances Directive) shows that
R48 classification should not be applied.
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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