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Toxicological information

Repeated dose toxicity: oral

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Administrative data

sub-chronic toxicity: oral
Type of information:
experimental study
Adequacy of study:
key study
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: The study was conducted under GLP and it was done according to valid methods, therefore it is considered relevant, reliable and adequate for classification.
Reason / purpose:
reference to same study

Data source

Reference Type:
study report
Report Date:

Materials and methods

Test guidelineopen allclose all
according to
EU Method B.27 (Sub-Chronic Oral Toxicity Test: Repeated Dose 90-Day Oral Toxicity Study in Non-Rodents)
according to
OECD Guideline 408 (Repeated Dose 90-Day Oral Toxicity in Rodents)
Principles of method if other than guideline:
No. of animals per group was limited to 10, of which the first 5 were the main group and the next 5 were used for 29-day recovery. This is not considered to impact the study as there is extensive dose response information from other 28- and 90-day toxicity studies.
GLP compliance:
Limit test:

Test material

Test material form:
solid: crystalline
Details on test material:
- Name of test material (as cited in study report): Chloracetamid, Chloressigsäureamid
- Physical state: White powder
- Analytical purity: 99.7%
- Impurities (identity and concentrations):See confidential details
- Composition of test material, percentage of components: See confidential details
- Purity test date: 1983-11-29
- Lot/batch No.: 791
- Stability under test conditions: 7 days stable in feed
- Storage condition of test material: In the dark at ca. 22 °C
- Other: Technical substance , manufactured 1983-07-19 , content of active ingredient in test substance 997 g/kg (according to report Dr. Their dd 1984-07-12)

Test animals

other: Wistar: Hoe: WISKf(SPF71)
Details on test animals and environmental conditions:
- Source: Hoechst AG, Hattersheim-Kastengrund (Germany), SPF-Zucht,
- Age at study initiation: Males ca. 4 weeks; females ca. 5 weeks
- Weight at study initiation: Average males 79.8 g; average females 85.4 g
- Housing: Draft mesh cages (Type 3), in groups until 2 animals
- Diet: Rattendiät Altromin 1321 by Altromin GmbH Lage/Lippe (Germany) ad libitum
- Water: Tap water in plastic bottles, ad libitum
- Acclimation period: At least 5 days before study

Fully airconditioned rooms

Administration / exposure

Route of administration:
oral: feed
unchanged (no vehicle)
Details on oral exposure:
PREPARATION OF DOSING SOLUTIONS: 1kg premix of the 10 fold end concentration was mixed together with 9 kg Altromin 1321 in a ploughshare mixer for 20 minutes. Every mixture was examined analytically for concentration and homogeneity of the test substance.

- Rate of preparation of diet (frequency): weekly
- Mixing appropriate amounts with (Type of food): Rattendiät Altromin 1321
Analytical verification of doses or concentrations:
Details on analytical verification of doses or concentrations:
Extraction of the active ingredient from the spiked diet using methanol (Chromasolv R). Concentration and dilution in methanol
(Chromasolv R). Determination of the active ingredient using gaschromatography with a nitrogen selective detector (PND).
(cf report Dr. Thier dd 1984-07-12 / encluded in the study report)
Duration of treatment / exposure:
90 days
Frequency of treatment:
Doses / concentrations
Doses / Concentrations:
0, 2, 10, 50 mg/kg bw/day
nominal in diet
No. of animals per sex per dose:
10 (of which the first 5 animals were used as the main group, and the next 5 animals for 29-day recovery)
Control animals:
Details on study design:
- Dose selection rationale: In an earlier 90 days oral repeated dose study doses of 12.5 and 50 mg/kg bw/day were administered. These doses were too high to determine a no effect level. Purpose of this experiment was to determine a no effect level.
- Rationale for selecting satellite groups: first 5 animals of each group were killed at the end of testing; the other 5 were killed after 29 days recovery period.
- Post-exposure recovery period in satellite groups:29 days


Observations and examinations performed and frequency:
-Monday - Friday 2x daily, on weekends 1x daily: behaviour /health state
-1x weekly: neurological disorders, opacities of eyes, injuries of the mouth's mucous membrane, disturbed toothgrowth
-2x weekly, during acclimation, study and recovery: body weight
-2x weekly during study: feed used; 1x weekly water used
-end of study or end of recovery period: haematological parameters in the blood: Hemoglobin; Erythrocyte count, Leucocyte count, Hematocrit, Reticulocyte count *, Heinz bodies *, Differential Blood Count, Platelet Count, Clotting time (* only in the control group and high dose group)
-after sacrifice: clinical-chemical parameters in the serum: Sodium, Potassium, Inorganic Phosphorus, Uric acid, Bilirubin total, Creatinine, Serum glucose, Urea-N (BUN), Calcium, Chloride, SGOT, SGPT, Alk. Phospatase
-night between 88./89. study day, 16 h urine: urinanalysis (animals unfeed, unwatered): Appearance, Color, Protein, Glucose, Hemoglobin, Bilirubin, pH value, Ascorbic acid, Ketone bodies, Density * (only from high dose and control group), Sediment

Sacrifice and pathology:
- Sacrifice by i.p. injection of 50 mg Nembutal / kg bw / de-bleeding by opening the vena cava cranialis
- gross assessment according to Hoechst Sektionsordnung I, Prof. K/G dd 1982-02-04
-relative organ weights (% of bw)
- histological assessment of fixated organ or preparations according to Hoechst Sektionsordnung I, Prof. K/G dd 1982-02-04: heart, lungs, liver, kidneys, spleen, stomach, jejunum, colon, bladder, testes, epidiymis, prostate, seminal vesicle, ovaries, uterus,thyroid, pancreas, adrenals, thymus, pituitary gland, brain, eyes with N. opticus, bone marrow (femur marrow)
Other examinations:
Feed analysis (see Table 1)
Statistical evaluation of following measured values, using probability level 0.05:
- body weight at observation times
- body weight gain during intervals
- haematological parameters (except differential blood count)
- clinical chemical parameters
- urinanalysis (pH, density)
- absolute/ relative organ weights
Hoechst evaluation software used according to SOP Dr. Passing, Department of Practical Mathematics.

Results and discussion

Results of examinations

Clinical signs:
no effects observed
no mortality observed
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):
no effects observed
Ophthalmological findings:
no effects observed
Haematological findings:
effects observed, treatment-related
Clinical biochemistry findings:
no effects observed
Urinalysis findings:
no effects observed
Behaviour (functional findings):
no effects observed
Organ weight findings including organ / body weight ratios:
effects observed, treatment-related
Gross pathological findings:
effects observed, treatment-related
Histopathological findings: non-neoplastic:
effects observed, treatment-related
Histopathological findings: neoplastic:
no effects observed
Details on results:
CLINICAL SIGNS AND MORTALITY: no effects, no mortalities during dosing & recovery period.
BODY WEIGHT AND WEIGHT GAIN: decreased in males & femaels in highest dose from week 2/3 onwards, respectively; reversible in recovery period.
FOOD CONSUMPTION AND COMPOUND INTAKE: decreased in males & females during first 30 days. No effects in recovery period.
WATER CONSUMPTION: no effects during dosing & recovery period.
OPHTHALMOSCOPIC EXAMINATION: no effects during dosing & recovery period.
HAEMATOLOGY: increased white blood cells at highest dose; reversible in recovery period.
CLINICAL CHEMISTRY: no effects during dosing & recovery period.
URINALYSIS: no effects during dosing & recovery period.
NEUROBEHAVIOUR: no effects during dosing & recovery period.
ORGAN WEIGHTS: male rats, highest dose: reduced testicular weights; still observed in the recovery group - decreased liver weight in females, highest dose; reversible in recovery period however decreased liver weight in males after recovery period.
GROSS PATHOLOGY: male rats, highest dose: smaller testes, reversible in the recovery group
HISTOPATHOLOGY: male rats, highest dose: depression - standstill of spermiogenesis and proliferation of Leydig cells and other interstitial cells in testes; absence of mature & immature sperms instead only loose connective tissue visible in epidydimides; in the recovery group starting to complete regeneration was observed.

Effect levels

open allclose all
Dose descriptor:
Effect level:
100 mg/kg diet
Based on:
test mat.
Dose descriptor:
Effect level:
10 mg/kg bw/day (actual dose received)
Based on:
test mat.

Target system / organ toxicity

Critical effects observed:
not specified

Any other information on results incl. tables

Table 1 Feed analysis

Mixture 1 (11.01.1984) Means
Dose mg/kg added    days after mg/kg found     mg/kg in
mg/kg test subst. act.ingr. preparation Act. Ingr. Test subst.   feed (real)
20 20,1 20 1 19 19    
20 20,1 20 1 14 14   16,5
100 100 99,8 1 92 92    
100 100 99,8 1 81 81   86,5
500 500 499 1 453 454    
500 500 499 1 479 480   467
Mixture 2 (22.02.1984)
Dose mg/kg added    days after mg/kg found     mg/kg in
mg/kg test subst. act.ingr. preparation Act. Ingr. Test subst.   feed (real)
20 20 19,9 1 16 16    
20 20 19,9 1 13 13   14,5
100 100 99,7 1 77 77    
100 100 99,7 1 78 78   77,5
500 500 499 1 396 397    
500 500 499 1 381 382   389,5
Mixture 3 (24.04.1984)
Dose mg/kg added    days after mg/kg found     mg/kg in
mg/kg test subst. act.ingr. preparation Act. Ingr. Test subst.   feed (real)
20 20 19,9 1 14 14    
20 20 19,9 1 14 14   14
100 100 99,7 1 63 63    
100 100 99,7 1 68 68   65,5
500 500 499 1 362 363    
500 500 499 1 361 362   362,5
Overall means
Nomimal doses feed Measured doses feed
mg/kg mg/kg
20 15,0
100 76,5
500 406,3

Applicant's summary and conclusion

Chloroacetamide in this 90 day oral repeated dose study in rats caused a decreased body weight gain and increased leucocyte count in the high dose male and female rats. The high dose males had smaller testes, depression- standstill of the spermiogenesis and proliferation of Leydig cells. After a 29 day recovery period, there were signs of beginning or ended regeneration of the testicular tubuli.
The NOAEL for Chloroacetamide in this study was determined to be 10 mg/kg bw/day.
Executive summary:

In a 90 day oral repeated dose study in Wistar rats were given doses of 0, 20, 100 and 500 mg Chloroacetamide test substance/kg feed /day. Each group consisted of 10 male and 10 female animals, of which the first 5 animals of each group, were killed at the end of the 90 day, whereas the other 5 were killed after a 29 day recovery period. In the high dose (500 mg/kg feed) male and female animals showed reduced body weight gain and food consumption and increased leucocytes in both sexes, decreased liver weights in females, and smaller testes, reduced testicular weights, proliferation of Leydig/other interstitial cells and depression - standstill of spermiogenesis in males.Re-onset in the recovery group with partial to complete regeneration of testes was observed in males, therefore this was to be designated as reversible. Further liver weights were reversed in females and slightly decreased in males in the hightest dose recovery groups. The NOAEL was determined to be 100 mg/kg feed, which was reported to correspond with 10 mg/kg bw/day.