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Administrative data

short-term repeated dose toxicity: oral
Type of information:
experimental study
Adequacy of study:
other information
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: GLP guideline study

Data source

Reference Type:
study report

Materials and methods

Test guideline
according to guideline
other: 96/54/EG, B.7; OECD 407 (1995) Siehe Bemerkungen.
GLP compliance:
Limit test:

Test material

Test animals

other: rat, Crl:CD(SD)

Administration / exposure

Route of administration:
oral: gavage
other: 0,5 % Methylcellulose
Details on oral exposure:
Method of administration:
Duration of treatment / exposure:
Test duration: 28 days
Frequency of treatment:
Dosing regime: 7 days/week
No. of animals per sex per dose:
Male: 5 animals at 5 mg/kg bw/day
Male: 5 animals at 15 mg/kg bw/day
Male: 5 animals at 50 mg/kg bw/day
Male: 5 animals at 100 mg/kg bw/day
Female: 5 animals at 5 mg/kg bw/day
Female: 5 animals at 15 mg/kg bw/day
Female: 5 animals at 50 mg/kg bw/day
Female: 5 animals at 100 mg/kg bw/day

Results and discussion

Results of examinations

Details on results:
Clinical observations:
Test substance-related death occurred at 100 mg/kg bw/d.

The 100 mg/kg bw/d dose group was terminated on day 17 due
to the test substance-related mortality and clinical signs
of severe toxicity within the group. Two males were found
dead on days 12 and 16, and one female was sacrificed in
extremis on day 13. Two females were accidentally killed,
one on day 2 (immediately after dosing), and one on day 3
(found dead), due to a dosing accident. The remainder three
males and two females were sacrificed on day 17 because of
severe toxic signs.

Clinical signs were noted approximately 1-3 hours post-
dosing on day of sacrifice or found dead and included
aggressive behaviour, convulsions, hypersensitivity,
hyperreactivity, salivation, and tremors. Test substance-
related adverse decrease in food consumption in animals at
100 mg/kg bw/d corresponded to reduced body weights and

mean body weight gains in animals treated at this dose
level. At 50 mg/kg bw/d adverse test substance-related
decreases (compared to controls) in mean body weights

(males / females: 6 - 13 % / 8 - 10 %), mean body weights
gains (males / females: 30 - 50 % / 29 - 60 %), and food
efficiency (males / females: 20 - 30 % / 30 - 40 %) were
observed in males and females. Food consumption was not
affected at this dose level.

No test substance-related effects were detected during
functional observational battery and motor activity
measurements in males and female receiving 50 mg/kg bw/d

and below.

Laboratory findings:
Haematology revealed statistically significant decreased

red blood cell counts (RBC), haemoglobin and hematocrit
values in parallel to significantly increased reticulocyte
counts for males and females at 15 and 50 mg/kg bw/d (except
for RBC, not significant in 15 mg/kg bw/d males; except for
reticulocyte count, not significant in 15 mg/kg bw/d
females). In males, statistically significant decreased
haemoglobin and hematocrit values were also noted at

5 mg/kg bw/d. Furthermore, statistically significant
decreased MCHC values were seen for males at 50 mg/kg bw/d
and for females at 15 and 50 mg/kg bw/d; statistically
significant increased red cell distribution width (RDW) was
determined for males at 15 and 50 mg/kg bw/d and for females
at 50 mg/kg bw/d. These haematology findings correlated with
histopathological findings of erythrocytic hyperplasia in
the bone marrow, and increased extramedullary haematopoiesis
in the spleen and liver.

Test substance-related adverse changes of clinical
biochemistry parameters suggestive of decreased glomerular
filtration in the kidney were present in males and/or
females treated with 50 mg/kg bw/d. These were statistically
significant increased urea nitrogen (males: 133 % of
controls), increased creatinine (males / females: 136 % /
126 % of controls), and increased inorganic phosphorous
(males / females: 124 % / 119 % of controls). In addition,
statistically significant decreased calcium values (92 % of
controls) in males and increased chloride values in males
and females (102 % / 103 % of control) were noted at

50 mg/kg bw/d. Bilirubin was statistically significant
increased (158 % and 150 % of control, respectively) in
males and females at 50 mg/kg bw/d, and was also
statistically significant increased in females treated at

5 and 15 mg/kg bw/d.

Urinalysis revealed statistically significant increased
total protein values for males treated at 50 mg/kg bw/d.

Effects in organs:
Test substance-related effects were noted in organ weights
and gross as well as microscopic examination in liver,
kidneys, spleen and bone marrow in both sexes.

The assessment of organ weights showed statistically
significant increases in absolute and relative liver

(50 mg/kg bw/d), kidney (50 mg/kg bw/d males;

>= 15 mg/kg bw/d females) and spleen (>= 15 mg/kg bw/d)
weights in animals of both sexes.

At necropsy discolouration of the kidneys (>= 15 mg/kg bw/d
males, 100 mg/kg bw/d females) and discolouration and
enlargement of the spleen (>= 50 mg/kg bw/d males,

100 mg/kg bw/d females) were observed that correlated with
microscopic findings in these organs.

Microscopy revealed test substance-related effects in the
kidney, spleen, liver and bone marrow:

Kidney: Renal cortical tubular degeneration and/or necrosis
with regeneration (i.e., renal cortical nephrosis) was
observed in all male and female rats given >= 15 mg/kg bw/d
and in 4/5 females given 5 mg/kg bw/d. The severity was
dose-related and females were more affected than males.

The nephrosis was characterized by degeneration and necrosis
of individual or clusters of epithelial lining cells in

the proximal convoluted tubules of the renal cortex.
Evidence of a regenerative response included increased
mitotic figures, hypercellular tubules with cytoplasmic
basophilia (basophilic tubules), and karyomegaly.


Increased extramedullary haematopoiesis was observed in
males and females given >= 15 mg/kg bw/d. Both the

incidence and severity were dose-related. An increase in

the amount of hemosiderin pigment was present in all

10 rats given 50 mg/kg bw/d, and in 4/5 females given

15 mg/kg bw/d. Congestion of the red pulp was apparent in
males and females dosed with >= 15 mg/kg bw/d.

Liver: Centrilobular hepatocellular hypertrophy was

observed in 5/5 males and 5/5 females dosed with

50 mg/kg bw/d. Extramedullary haematopoiesis was observed

in 2/5 males and 2/5 females given 50 mg/kg bw/d. Increased
hemosiderin pigment in Kupffer cells was noted in 3/5 males
and in 5/5 females at 50 mg/kg bw/d.

Bone marrow:

An increase in erythrocytic hyperplasia was seen in

4/5 males and in 5/5 females at 50 mg/kg bw/d. The
hyperplasia correlated with increased red blood cell
haematopoiesis in spleen and liver as well as

haematology findings.

Target system / organ toxicity

Critical effects observed:
not specified

Applicant's summary and conclusion

Classified as R48/25 - STOT RE1, H372