Dipotassium disulphate

Repeated dose toxicity: oral

Administrative data

Endpoint:

sub-chronic toxicity: oral

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: This study was selected as the key study because the information provided for the hazard endpoint is sufficient for the purpose of classification and labelling and/or risk assessment.

Cross-reference

Reason / purpose for cross-reference:

reference to same study

Data source

Reference

Reference Type:

publication

Title:

13-Week Subchronic Oral Toxicity Study of Ammonium Sulfate in Rats

Author:

Takagi H, Onodera H, Yun L, Yasuhara K, Koujitani T, Mitsumori K, and Hirose M

Year:

1999

Bibliographic source:

Kokuritsu Iyuakuhin Shokuhin Eisei Kenkyusho Hokoku [Bull. Natl. Health Sci.], 117:108-114

Materials and methods

Principles of method if other than guideline:

A 13-week subchronic oral toxicity study was performed in male and female rats

GLP compliance:

not specified

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

Ammonium sulphate

EC Number:

231-984-1

EC Name:

Ammonium sulphate

Cas Number:

7783-20-2

IUPAC Name:

diammonium sulfate

Details on test material:

- Purity: Not reported

Test animals

Species:

rat

Strain:

Fischer 344/DuCrj

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River Japan
- Age at study initiation: ~6 weeks
- Weight at study initiation: not reported
- Fasting period before study: No
- Housing: 5per plastic cage using soft chips as bedding
- Diet (e.g. ad libitum): ad libitum
- Water (e.g. ad libitum): not reported
- Acclimation period: 1 week

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 24±1°C
- Humidity (%): 55±5%
- Air changes (per hr): 18
- Photoperiod (hrs dark / hrs light): 12/12

Administration / exposure

Route of administration:

oral: feed

Vehicle:

unchanged (no vehicle)

Details on oral exposure:

DIET PREPARATION: Food was stored at room temperature until used. Stability was checked for one week at room temperature.

Analytical verification of doses or concentrations:

not specified

Duration of treatment / exposure:

13 Weeks

Frequency of treatment:

Continuously in the diet

Doses / concentrations

Doses / concentrations 1

Remarks:

Doses / Concentrations:
0.38, 0.75, 1.5, 3%
Basis:
nominal in diet

Doses / concentrations 2

Remarks:

Doses / Concentrations:
220, 441, 886, 1792 mg/kg/day (males); 239, 484, 961, 1975 mg/kg/day (females)
Basis:
actual ingested

No. of animals per sex per dose:

10/sex/dose

Control animals:

yes, plain diet

Details on study design:

- Dose selection rationale: In a 2-week preliminary study, female F344 rats were administered 5% of the test substance in diet. Significant weight gain suppression and diarrhoea were observed when compared to controls. Based on these findings, the doses selected for the 13-week subchronic toxicity study were 0.38, 0.75, 1.5, and 3%.

Examinations

Observations and examinations performed and frequency:

CAGE SIDE OBSERVATIONS: Yes
- Time schedule: Daily
- Cage side observations checked : Mortality, behaviour

DETAILED CLINICAL OBSERVATIONS: No data

BODY WEIGHT: Yes
- Time schedule for examinations: Weekly

FOOD CONSUMPTION AND COMPOUND INTAKE (if feeding study): Yes
- Time schedule: Weekly

FOOD EFFICIENCY: No

WATER CONSUMPTION AND COMPOUND INTAKE: No

OPHTHALMOSCOPIC EXAMINATION: No

HAEMATOLOGY: Yes
- Time schedule for collection of blood: Blood was collected from the aorta abdominalis post mortem (during necropsy)
- Anaesthetic used for blood collection: No
- Animals fasted: No data
- How many animals: All
- Parameters examined: erythrocyte count, haemoglobin, haematocrit, mean cell volume, mean corpuscular haemoglobin content, mean corpuscular haemoglobin concentration, platelet count, leukocyte count

CLINICAL CHEMISTRY: Yes
- Time schedule for collection of blood: Blood was collected from the aorta abdominalis post mortem (during necropsy)
- Animals fasted: No data
- How many animals: All
- Parameters examined: total protein, albumin/globulin ratio, albumin, total cholesterol, urea nitrogen, sodium, chloride, potassium, calcium, inorganic phosphorus, glutamat-oxaloacetic transaminase, glutamate-pyruvat transaminase, alkaline phosphatase

URINALYSIS: No

NEUROBEHAVIOURAL EXAMINATION: No

Sacrifice and pathology:

GROSS PATHOLOGY: Yes
HISTOPATHOLOGY: Yes

Brain, heart, lungs, liver, kidneys, adrenals, spleen, testes, and thymus were weighed. In addition to these, other main organs were fixed (10% neutral buffered formalin), sectioned, stained (haematoxyline and eosin) and examined histologically.

Statistics:

Variance in data for body weights, haematology, serum biochemistry, and organ weights was checked for homogeneity by the Bartlett test. When the data were homogeneous, one-way analysis of variance (ANOVA) was used. When a significant difference between groups was observed, the Dunnett method was used when the number of animals per group was equal or the Schiff method was used when the number of animals per group was unequal. When dispersion was not equal, the Kruskal-Wallis test was applied and when statistically significant differences were indicated, Dunnett's or Schiff test was employed.

Results and discussion

Results of examinations

Clinical signs:

effects observed, treatment-related

Mortality:

mortality observed, treatment-related

Body weight and weight changes:

no effects observed

Food consumption and compound intake (if feeding study):

no effects observed

Food efficiency:

not examined

Water consumption and compound intake (if drinking water study):

not examined

Ophthalmological findings:

not examined

Haematological findings:

no effects observed

Clinical biochemistry findings:

no effects observed

Urinalysis findings:

not examined

Behaviour (functional findings):

not examined

Organ weight findings including organ / body weight ratios:

no effects observed

Gross pathological findings:

no effects observed

Histopathological findings: non-neoplastic:

no effects observed

Histopathological findings: neoplastic:

no effects observed

Details on results:

CLINICAL SIGNS AND MORTALITY: No mortality was observed. Diarrhoea was observed in the males at 3% starting at week 1 continuing throughout the study.

BODY WEIGHT AND WEIGHT GAIN: Body weight gain was significantly decreased in 3% males when compared with controls.
Final mean body weights were significantly decreased in males receiving 0.38%, 1.5% and 3%, and significantly increased in females of the same groups when compared with controls. The changes in the 0.38% group were not dose-related.

FOOD CONSUMPTION: There were no significant differences between the groups for both males and females.

HAEMATOLOGY and CLINICAL CHEMISTRY: The following, statistically significant and dose-related changes were observed:
- decreased leukocyte count (3% males)
- decreased erythrocyte count, haemoglobin, decreased haematocrit, and platelet count (3% females).
- increased mean corpuscular haemoglobin content and mean corpuscular haemoglobin concentration (3% females)
The same changes in haematological parameters were also observed in 1.5% males and females; however, these changes were not dose-related.
Blood serum analysis revealed some statistically significant alterations; however, there was no dose-response. These changes were not considered biologically significant, as they were within the limits of background data and no anomalies were observed in the haematopoietic organs.

ORGAN WEIGHTS: Increased absolute and relative spleen weights (males only) and kidney weights (males and females) were observed at 3%. Relative testis weights were increased at all dose levels and relative liver weight was increased in females at all doses. However, no dose-related trend was observed. Therefore, the authors did not consider these findings adverse or indicative of obvious test substance toxicity.

PATHOLOGY: Histological examination revealed myofibrosis cordis (3% males), basophilia of the renal tubuli (3% males and females), and melanosis of the spleen (3% males and females). However, the incidence of these findings was not statistically significantly different from control.

According to the authors, with exception of the diarrhoea observed in high dose males, none of these observations was considered to indicate obvious toxicity of the test substance.

Effect levels

1

Dose descriptor:

NOEL

Effect level:

1.5 other: % (886 mg/kg bw/day)

Sex:

male

Basis for effect level:

other: based on diarrhoea observed in 3% males

2

Dose descriptor:

NOEL

Effect level:

3 other: % (1975 mg/kg/day)

Sex:

female

Basis for effect level:

other: no adverse effects at highest dose tested

Target system / organ toxicity

Critical effects observed:

not specified

Applicant's summary and conclusion

Conclusions:

NOAEL: 1.5% (886 mg/kg/day) for males and 3% (1975 mg/kg/day) for females
This study and the conclusions which are drawn from it fulfil the quality criteria (validity, reliability, repeatability).

Executive summary:

A 13-week subchronic oral toxicity study of ammonium sulphate was performed in both sexes of F344 rats by feeding them a CRF-1 powder diet containing concentrations of 0.38, 0.75, 1.5, and 3.0% of the test substance. A control group was fed plain diet. Rats were randomly divided into 5 groups each consisting of 10 males and 10 females. The mean daily doses were 220, 441, 886, 1792 mg/kg bw/day for males, and 239, 484, 961, 1975 mg/kg bw/day for females. Male animals in the 3% group exhibited diarrhoea during the administration period. No changes indicating obvious ammonium sulphate toxicity were observed in the body weights, organ weights, haematological, serum biochemical, or histopathological examinations. Based on these results, the NOEL (no-observed-effect level) of ammonium sulphate for F344 rats was judged to be 1.5% in males (886 mg/kg/day) and 3% in females (1975 mg/kg/day).