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Toxicological information

Repeated dose toxicity: oral

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Administrative data

Endpoint:
sub-chronic toxicity: oral
Type of information:
experimental study
Adequacy of study:
key study
Study period:
1965
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: No data on batch no. and composition. Reporting is limited. The study was performed pre-GLP. No guideline was available.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1965
Report Date:
1965

Materials and methods

Test guideline
Qualifier:
no guideline followed
Principles of method if other than guideline:
Haematology parameters were limited. No clinical biochemistry was performed. No data reported on frequency and set up of
observations and clinical signs. Ophthalmological examinations and functional observations were not performed.
GLP compliance:
no
Remarks:
pre-GLP
Limit test:
no

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
No furher data.

Test animals

Species:
rat
Strain:
Wistar
Sex:
male/female
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: own colony maintained at Alderley Park, Cheshire, UK
- Weight at study initiation: 126-310 g (males), 88-232 g (females)
- Age at study initiation: no data
- Fasting period before study: no info
- Housing: 5/cage in Wilmslow-type mobile rat units (wire mesh cages on 3 sides and floor)
- Diet (e.g. ad libitum): ad lib
- Water (e.g. ad libitum): ad lib
- Acclimation period: in house colony


ENVIRONMENTAL CONDITIONS
- Temperature (°C): no data
- Humidity (%): no data
- Air changes (per hr): no data
- Photoperiod (hrs dark / hrs light): no data


IN-LIFE DATES: no data

Administration / exposure

Route of administration:
oral: feed
Vehicle:
maize oil
Details on oral exposure:

DIET PREPARATION:

All diets were pregered in tho central diet room of the Laboratories. The basic ration from which all diets were made was a
standard pulverised rat stock diet. The control diet contained powdered stock diet, 20 parts, malt extract, 18 parts, and maize oil , 2 parts, all by weight. Experimental diets were identical with the control except that the calculated weight of Ethomeen was
incoporated into the diet via the maize oil, in which it was dissolved by gentle heating at 40 degrees C. The ingredients were mixed mechanically and watar added to produce e dough. The mixture was extruded through a sausage-meat machine which moulded thediet into pieces of' 3 - 5 cm long and approximately 1 cm in diameter. These were then dried in a vacuum oven at a temperature of
not more than 40°C.
Analytical verification of doses or concentrations:
no
Details on analytical verification of doses or concentrations:
No analyticak verification.
Duration of treatment / exposure:
90 days
Frequency of treatment:
ad libitum in the feed
Doses / concentrations
Remarks:
Doses / Concentrations:
170, 500, 1500, 4500 ppm
Basis:
nominal in diet
No. of animals per sex per dose:
25 sex/group, in the higest dose group 10 sex/group. In addition a further group of 14 rats, 7 males and 7 females, were fed diet
containing 4500 ppm Ethomeen T/12 end killed at intervals up to 6 weeks from the beginning of the experiment. Tissues from these
animals were examined for sudanophilic material.
Control animals:
yes, plain diet
Details on study design:
- Dose selection rationale: no info
- Rationale for animal assignment (if not random): at random
- Section schedule rationale (if not random): no info
Positive control:
Not used.

Examinations

Observations and examinations performed and frequency:
CAGE SIDE OBSERVATIONS: Yes, but frequency of observations not indicated.

DETAILED CLINICAL OBSERVATIONS: No data

BODY WEIGHT: Yes / No / No data
Initially, the body weight of each rat was determined and recorded. Subsequently all animals were weighed weekly during the course of tho experiment.

FOOD CONSUMPTION:
Measured daily during 1 week in 0, 1500 and 4500 ppm groups.

FOOD EFFICIENCY: No data

WATER CONSUMPTION AND COMPOUND INTAKE (if drinking water study): No data

OPHTHALMOSCOPIC EXAMINATION: No data

HAEMATOLOGY:
Haemoglobin concentrations, packed-cell volumes, white-cell counts and differential white-cell counts were measured pre-
experimentally and imediately prior to killing the animals at the end of the feeding period, These studies were done on individual
samples from 5 male and 5 female rats from each group except-that blood was examined from all animals fed diet containing the
highest level of Ethomeen T/12.

CLINICAL CHEMISTRY: No data

URINALYSIS: No data

NEUROBEHAVIOURAL EXAMINATION: No data

Sacrifice and pathology:
PATHOLOGY:
At the end of the 90-day test period all animals were killed with chloroform and an immediate full post-mortem examination made.
Absolute organ weights were recorded and organ/body weight ratios calculated from a random selection of animals in each group. The following organs wore included: liver, heart, lung, adrenals, kidneys, spleen. Tissues and organs of the remaining animals werefixed in Zenker's fluid except brains, which ware fixed in 10% formal saline, and examined microscopically. The following tissues
and organs were examined: liver, kidney, spleen, heart, lung, adrenals, gonads, thymus, thyroid, pancreas, stomach, duodenum,
jejunum, ileum, caecum, colon, salivary gland, mesenteric lymph nodes, spinal cord and brain (cerebrum, cerebellum and medulla).
Other examinations:
No
Statistics:
Not used.

Results and discussion

Results of examinations

Clinical signs:
not specified
Mortality:
not specified
Body weight and weight changes:
effects observed, treatment-related
Food consumption and compound intake (if feeding study):
effects observed, treatment-related
Food efficiency:
not specified
Water consumption and compound intake (if drinking water study):
not specified
Ophthalmological findings:
not examined
Haematological findings:
no effects observed
Clinical biochemistry findings:
not examined
Urinalysis findings:
not examined
Behaviour (functional findings):
not examined
Organ weight findings including organ / body weight ratios:
no effects observed
Gross pathological findings:
effects observed, treatment-related
Histopathological findings: non-neoplastic:
effects observed, treatment-related
Histopathological findings: neoplastic:
no effects observed
Details on results:
Mortality and Reactions:
No deaths occurred prematurely and males and females responded similarly. At the highest dose level hairloss was observed and
the animals were generally lethargic throughout the experiment. At the other dose levels no effects were noted.

Body weights:
At 4500 ppm, no body weight gain was observed and at 1500 ppm a decreased body weight gain was observed. At lower levels
no effects were observed.

Food consumption:
The palatability of the diet was affected by the addition of 4500 and 1500 ppm test compound.

Haematology:
No effects were noted.

Pathology:
Changes attributed to treatment were seen only in animals at a dietary level of 4500 ppm. These changes were confined to the
gastrointestinal tract. The stomach and bowel content of all rats at this dietary level was yellow and the mucooa of the small
intestine was thickened and yellow. The mean organ body-weight ratios were not different from controls. Abnormality was seen
only at a dietary level of 4,500 ppm and 1,500 pppm and was confined to the small intestine and regional mesenteric nodes. All
animals fed 4,500 ppm in the diet showed engorgement of the villi and lamina propria of the small intestine with swollen foamy
macrophages. Similar macrophages are occasionally seen to a lesser degree in Peyer's patches and in the regional lymph nodes.
Changes were most proounced In the jejunum and upper ileum but could be detected throughout the small intestine. The
macrophages were sudanophilic and were presumed to contain deposits of Ethomeen. The other components of the intestinal wall
appeared completely normal. A similar change was present to a lesser degree in 31 of 40 rats fed a dietary level of 1,500 ppm. No
changes were present ot a dietary level of 500 ppm or less of Ethomeen T/12.

Effect levels

Dose descriptor:
NOEL
Effect level:
500 ppm
Sex:
male/female
Basis for effect level:
other: At higher levels animals did not gain weight normally and showed pathological lesions confined to the small intestines and its regional lymph nodes. This dietary level of 500 ppm corresponds to ca. 35 mg/kg bw/day (see below)

Target system / organ toxicity

Critical effects observed:
not specified

Any other information on results incl. tables

A NOEL of 500 ppm in the diet corresponds with:

ca. 33 mg/kg bw in males (taking into account a mean food intake of 20 g/day and a mean BW of 300 g throughout the study period)

ca. 35 mg/kg bw in females (taking into account a mean food intake of 15 g/day and a mean BW of 200 g throughout the study period)

Applicant's summary and conclusion

Conclusions:
From this study a NOEL of 500 ppm can be derived. At higher levels animals did not gain weight normally and showed pathological
changes confined to the small intestines and its regional lymph nodes. This dietary level corresponds to ca. 35 mg/kg bw/day.
Executive summary:

The test substance Ethomeen T/12 was administered via the diet daily for 90 days to Wistar rats. One control group and four treated groups were tested, each consisting of 25 males and 25 females (except for the high dose group that had 10 animals per sex). These were exposed to 0, 170, 500, 1500 or 4500 ppm. A further group of 14 rats, 7 males and 7 females, was fed a diet containing 4500 ppm Ethomeen T/12 end killed at intervals up to 6 weeks from the beginning of the experiment. Tissues from these animals were examined for sudanophilic material.

The following parameters were evaluated: clinical signs, body weight and food consumption, haematology, and macroscopy at termination, organ weights and histopathology on a selection of tissues.

No deaths occurred prematurely and males and females responded similarly. At the highest dose level hairloss was observed and the animals were generally lethargic throughout the experiment. At the other dose levels no effects were noted. Body weights: At 4500 ppm, no body weight gain was observed and at 1500 ppm a decreased body weight gain was observed. At lower levels no effects were observed. Food consumption: The palatability of the diet was affected by the addition of 4500 and 1500 ppm test compound. Haematology: No effects were noted. Pathology: Changes attributed to treatment were seen only in animals at a dietary level of 4500 ppm. These changes were confined to the gastrointestinal tract. The stomach and bowel content of all rats at this dietary level was yellow and the mucooa of the small intestine was thickened and yellow. The mean organ body-weight ratios were not different from controls. Abnormality was seen only at a dietary level of 4,500 ppm and 1,500 pppm and was confined to the small intestine and regional mesenteric nodes. All animals fed 4,500 ppm in the diet showed engorgement of the villi and lamina propria of the small intestine with swollen foamy macrophages. Similar macrophages are occasionally seen to a lesser degree in Peyer's patches and in the regional lymph nodes. Changes were most proounced In the jejunum and upper ileum but could be detected throughout the small intestine. The macrophages were sudanophilic and were presumed to contain deposits of Ethomeen T/12. The other components of the intestinal wall appeared completely normal. A similar change was present to a lesser degree in 31 of 40 rats fed a dietary level of 1,500 ppm. No changes were present ot a dietary level of 500 ppm or less of Ethomeen T/12.

From this study a NOEL of 500 ppm can be derived. At higher levels animals did not gain weight normally and showed pathological changes confined to the small intestines and its regional lymph nodes. This dietary level corresponds to ca. 35 mg/kg bw/day.