sodium 1,3,5-triazinane-2,4,6-trione

Endpoint summary

Description of key information

Experimental results from repeated dose studies by the oral route (59 day, 13 week (according to OECD guideline 408) and 104 weeks (according to EU Method B.33) on sodium cyanurate monohydrate or sodium cyanurate. 
Read-across from a 13-week study with cyanuric acid. 

Key value for chemical safety assessment

Repeated dose toxicity: via oral route - systemic effects

Link to relevant study records

Reference

Endpoint:

chronic toxicity: oral

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Study performed to GLP and equivalent to guideline

Qualifier:

equivalent or similar to guideline

Guideline:

EU Method B.33 (Combined Chronic Toxicity / Carcinogenicity Test)

GLP compliance:

yes

Species:

rat

Strain:

other: Charles River CD

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River Breeding Laboratories, Inc. Portage, Michigan, USA
- Age at study initiation: ~5 weeks old
- Weight at study initiation: males: 87.0-164.0 g; females 72.0 – 141.0 g
- Housing: Suspended wire mesh cages
- Diet: Provided ad libitum
- Water: Provided ad libitum



ENVIRONMENTAL CONDITIONS
- Temperature (°F): 71
- Humidity (%): 59-61
- Photoperiod (hrs dark / hrs light): 12/12

Route of administration:

oral: drinking water

Vehicle:

water

Details on oral exposure:

PREPARATION OF DOSING SOLUTIONS: The appropriate amount of test material was dissolved in tap water and mixed using a motor driven propeller. The pH of the testing solutions was adjusted to pH 7.4 using glacial acetic acid and/or sodium hydroxide. Fresh drinking water solutions were prepared 3 times weekly.

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

Samples of drinking water from all groups were analysed on days 1, 3, 5 and of weeks 1 through 15 and on day 1 of weeks 16 through 106

Duration of treatment / exposure:

104 weeks

Frequency of treatment:

ad libitum / continuous

Remarks:

Doses / Concentrations:
0, 400 ppm, 1200 ppm, 2400 ppm, 5375 ppm (males ~ 25, 76, 154, 371 mg/kg bw/d; females ~ 42, 129, 266, 634 mg/kg bw/d).
Basis:

No. of animals per sex per dose:

Low dose group: 80/sex
Mid dose, mid-high dose and high dose groups: 100/sex/dose level
Tap water control: 100/sex
Sodium control: 80/sex

Control animals:

other: Vehicle (tap water), Sodium control (sodium hippurate)

Observations and examinations performed and frequency:

CAGE SIDE OBSERVATIONS: Yes
- Time schedule: Twice daily


DETAILED CLINICAL OBSERVATIONS: Yes
- Time schedule: Weekly


BODY WEIGHT: Yes
- Time schedule for examinations: Recorded weekly during the pretest and first 14 weeks of the study, every 2 weeks thereafter


FOOD CONSUMPTION: Yes
- Time schedule for examinations: recorded weekly for the first 14 weeks of the study, every 2 weeks thereafter

WATER CONSUMPTION AND COMPOUND INTAKE (if drinking water study): Yes
- Time schedule for examinations: Weekly


OPHTHALMOSCOPIC EXAMINATION: No


HAEMATOLOGY: Yes
- Time schedule for collection of blood: 6, 12, 18 and 24 months
- Anaesthetic used for blood collection: No data
- Animals fasted: Yes
- How many animals: 10 rats/sex
- Parameters checked: Total and differential leukocyte count, erythrocyte count, haemoglobin, haematocrit, platelet count, reticulocyte count, haematological indices mean corpuscular volume (MCV), mean corpuscular haemoglobin (MCH) and mean corpuscular haemoglobin concentration (MCH).


CLINICAL CHEMISTRY: Yes
- Time schedule for collection of blood: 6, 12, 18 and 24 months
- Animals fasted: Yes
- How many animals: 10 rats/sex
- Parameters checked: Sodium, potassium, chloride, calcium, phosphorous, osmolality, alkaline phosphatase, total bilirubin, aspartate aminotransferase, alanine aminotransferase, lactic dehydrogenase, blood urea nitrogen, creatinine, total protein, albumin, globulin (calculated), cholesterol and glucose.


URINALYSIS: Yes
- Time schedule for collection of urine: 6, 12, 18 and 24 months
- Metabolism cages used for collection of urine: No
- Animals fasted: Yes
- Parameters checked: Colour and appearance, microscopic examination of sediment, volume, osmolality, pH, protein, glucose, occult blood, nitrites, bilirubin, ketones, urobilinogen, sodium, potassium, chloride, magnesium, phosphorous, calcium, urea nitrogen, creatinine


NEUROBEHAVIOURAL EXAMINATION: No

Sacrifice and pathology:

GROSS PATHOLOGY: Yes all animals received a complete post mortem.
Organs: external examination; contents of the abdominal, thoracic and cranial cavities were examined both in situ and after removal and dissection. Adrenal, all gross lesions, all tissue masses, brain (fore-, mid-, and hind-), cecum, colon, duodenum, esophagus, eye and contiguous Harderian gland, heart with coronary vessels, ileum, jejunum, kidneys, liver (3 sections) lung and mainstream bronchi, lymph nodes (medistinal, mesenteric and regional), mammary gland, ovaries, pancreas, peripheral nerve (sciatic), pituitary, prostate / corpus and cervix uteri, mandibular salivary gland, skeletal thigh muscle, skin, spinal cord (cervical and thoracic), spleen, sternum bone marrow, stomach, testis with epididymus, thymus, thyroid and parathyroid, tongue, trachea, ureter, urinary bladder, whole head (including nasal, oral and otic tissue) and Zymbal’s gland.

HISTOPATHOLOGY: Yes a full tissue compliment was prepared for all animals in control and high dosage groups. Sections of the following organs from animals in the 400 ppm, 1200 ppm, 2400 ppm groups sacrificed at 6, 12and 18 months and all animals which died or were sacrificed in extremis between 0 and 24 months of study: adrenal, heart, kidneys, liver, ovaries, spleen, testes, ureter, urinary bladder, tissue masses and gross lesions. Gross lesions and tissue masses were microscopically examined for animals in the 400 ppm, 1200 ppm, 2400 ppm dose groups which survived to terminal sacrifice

Statistics:

Body weights and food consumption (weekly for weeks 1 – 4, quarterly thereafter) organ weights, (absolute and relative to body weights, interim and terminal sacrifices) clinical laboratory values (6, 12, 18 and 24 months prior to interim and terminal sacrifices) were analysed by Bartlett’s test for homogeneity of variance and analysis of variance (one-way classification). Treatment groups were compared to the control group and to the sodium control group by sex, using the appropriate t-statistic (equal or unequal variance) as described by Steel and Torrie and Ostle. Dunnett’s multiple comparison tables were used to determine significance. All statistical tests were two-tailed. Survival data and data on time to neoplastic lesion were analysed using the computer program of Thomas, Breslow and Gart. Statistical procedures included in this program are the Kaplan-Meier and standard methods for computing survival curves, Cox’s test for linear trend in proportions and both Cox’s test and Gehan-Breslow’s generalized Kruskall-Wallis test for comparing survival distributions. Data on time to neoplastic lesion were analysed for all benign tumors, all malignant tumors, all tumors combined and for individual type that appeared in two or more animals in the high dose group

Clinical signs:

effects observed, treatment-related

Mortality:

mortality observed, treatment-related

Body weight and weight changes:

effects observed, treatment-related

Food consumption and compound intake (if feeding study):

no effects observed

Food efficiency:

not examined

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

effects observed, treatment-related

Ophthalmological findings:

not examined

Haematological findings:

no effects observed

Clinical biochemistry findings:

no effects observed

Urinalysis findings:

no effects observed

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:
Red urine was observed for 5375 ppm group males (week 1 – 62) and appeared to be test article related and correlated with the high incidence of urinary bladder calculi. Decreased defecation and / or no faeces occurred more frequently for 5375 ppm group males (week 1 – 62) and a slightly higher incidence of yellow material (anogenital region, ventral surface, ventral abdomen, hindlimb) for 2400 and 5375 ppm female groups (weeks 14 – 39) and for male rats in the 5375 ppm group (weeks 1 – 52). In weeks 14 – 52 some male rats in the 5375 ppm group were noted to feel cold to the touch.
Survival was a little lower for high dose males (5375 ppm) as compared to control animals in weeks 26 – 104. Females given 1200 ppm and 2400 ppmhad a lower survival rate at 104 weeks compared to control animals

BODY WEIGHT AND WEIGHT GAIN:
Male control and treatment withdrawal rats were similar in weeks 63 – 104. The body weight of the withdrawal rats was also similar to their respective male groups not placed on compound withdrawal. Group mean body weights of female rats receiving 2400 and 5375 ppm after withdrawal were higher compared to group mean body weights of female control withdrawal animals and non withdrawal females receiving 2400 and 5375 ppm

FOOD CONSUMPTION AND COMPOUND INTAKE (if feeding study)
Group mean food consumption values for both males and females were similar in all groups including the untreated controls. Overall. the with drawal animals in all groups consumed more food (g/rat/day) during the recovery period than the animals in the main study.

WATER CONSUMPTION AND COMPOUND INTAKE (if drinking water study)
Water consumption of male and female treatment groups and the sodium control group was higher than those of the control group. The increased water consumption appeared dose related. No definite trend in water consumption of the compound withdrawal group was evident. Average water consumption (weeks 63 – 104) of male and female 2400 ppm and 5375 ppm withdrawal groups was higher than those of male and female control groups during the recovery period. Male and female 5375 ppm withdrawal groups showed decreased average water consumption as compared to non withdrawal male and female 5375 ppm groups in weeks 63 – 104

HAEMATOLOGY
No significant treatment related effects were observed.

CLINICAL CHEMISTRY
No results of pathologic significance were observed

URINALYSIS
No significant treatment related effects were observed


ORGAN WEIGHTS
There were no test article related organ weight variations in the treatment groups at any of the interim or terminal sacrifices

GROSS PATHOLOGY
Calculi in the kidney (pelvis) or urinary bladder, hydronephrosis, hydroureter, blood in urine and distention of urinary bladder were test article related in male rats from the 5375 ppm group sacrificed at the 6 month interim, died / sacrificed in extremis during the 0 – 12 month period of the study. Urolithiasis was the primary lesion. None of the rats at 12, 18 or 24 months or any rat that died / sacrificed in extremis during the 12 – 24 month periods showed any test article effects.

HISTOPATHOLOGY: NON-NEOPLASTIC
No evidence of a test article related carcinogenic effect was observed in any tissues or organs examined microscopically from male or female rats from any of the experimental groups. A non neoplastic change of questionable toxicological significance occurred in the kidneys of a small number of female rats from the 5375 ppm group which died or were sacrificed in extremis during the period 6 – 12 months.
Urinary tract lesions were probably related to the presence of urinary tract calculi. These lesions included hyperplasia of the urinary bladder epithelium, acute cystitis and hemorrhage in the bladder wall, which correlated with macroscopic observations of bladder calculi. Almost all test article related urinary tract lesions were limited to male rats from the 5375 ppm group which died, were sacrificed in extremis or were electively sacrificed in the first 12 months of study with most occurring in animals which died or were sacrificed in extremis. Hydroureter was sometimes associated with bladder calculi, some dilated ureters were also inflamed and hemorrhagic. Test article related kidney lesions consisted of tubular nephrosis in some rats from the 5375 ppm group which died or were sacrificed in extremis during the period 6 - 12 months. Calculi were noted in the bladders of some affected males, no calculi were found in any of the affected females. Test article related urinary tract lesions only occurring in the first 12 months of study suggests that some males by the nature of their urinary tract structure were more prone to obstruction and succumbed early. Occurrence of bladder epithelial hyperplasia and associated test article related bladder lesions in rats which did not have grossly evident calculi is consistent with a calculus based mechanism. Calculi which were transiently present but which were small enough to pass on the urine stream would cause irritation during their residence in the bladder. Uremia due to urinary tract obstruction by calculi was the probable cause of death in animals in which calculi could not be passed.
Heart lesions in 5375 ppm males which died or were sacrificed in extremis during the first 12 months of study also had urinary bladder calculi and or distention at necroscopy suggesting that the heart lesions were of uremic etiology, secondary to urinary tract obstruction.
An increased incidence of splenic hemosiderosis in male rats of the 5375 ppm group was possibly test article related but did not correlate with any alteration in clinical pathologic parameters.

Dose descriptor:

NOAEL

Effect level:

ca. 154 mg/kg bw/day (nominal)

Sex:

male

Dose descriptor:

NOAEL

Effect level:

ca. 266 mg/kg bw/day (nominal)

Sex:

female

Dose descriptor:

LOAEL

Effect level:

ca. 371 mg/kg bw/day (nominal)

Sex:

male

Dose descriptor:

LOAEL

Effect level:

ca. 634 mg/kg bw/day (nominal)

Sex:

female

Critical effects observed:

not specified

Executive summary:

Sodium cyanurate was administered in the drinking water in a two year toxicity and oncogenicity study in rats.  Non-neoplastic lesions were observed in urinary tracts of males in the 5375 ppm group sacrificed at the 6 and 12 month interims.  Heart and urinary tract lesions occurred in 5375 ppm males which died or were sacrificed in extremis during the first 12 months of the study.  The only possible substance related changes in females were in the urinary tract of the 5375 ppm animals which died or were sacrificed in extremis during the 6 – 12 month period of study.  In the 18 month interim sacrifice and the 24 month terminal sacrifice no lesions were detected which could be attributed to treatment with the test article.

No evidence of test article related carcinogenic effect was observed in any tissues or organs examined microscopically from male or female rats of any test group.

Endpoint conclusion

Endpoint conclusion:

adverse effect observed

Dose descriptor:

NOAEL

154 mg/kg bw/day

Study duration:

chronic

Species:

rat

Quality of whole database:

Study performed to GLP and equivalent to guideline (Klimisch 1).

Repeated dose toxicity: inhalation - systemic effects

Endpoint conclusion

Endpoint conclusion:

no study available

Repeated dose toxicity: inhalation - local effects

Endpoint conclusion

Endpoint conclusion:

no study available

Repeated dose toxicity: dermal - systemic effects

Endpoint conclusion

Endpoint conclusion:

no study available

Repeated dose toxicity: dermal - local effects

Endpoint conclusion

Endpoint conclusion:

no study available

Additional information

Oral Exposure:

1. Experimental results obtained with the substance monosodium salt of cyanuric acid (LOAEL > 4000 ppm and NOAEL = 4000 ppm).

Read-across: 2. Based on the experimental results obtained with the analogue cyanuric acid (NOAEL ca.231 mg/kg bw/day male; NOAEL ca. 914 mg/kg bw/day female; LOAEL ca. 109 mg/kg bw/day male; LOAEL ca. 915 mg/kg bw/day female), the read-across approach is applied and the NOAEL and LOAEL for substance sodium cyanurate are calculated to be NOAEL ca 272 mg/kg bw/day male; NOAEL ca. 1076 mg/kg bw/day female; LOAEL ca. 128 mg/kg bw/day male; LOAEL ca. 1078 mg/kg bw/day female under test conditions.

3. Experimental results obtained with the substance monosodium salt of cyanuric acid, monohydrate (NOAEL = 5375 ppm and LOAEL < 5375 ppm).

4. Experimental results obtained with the substance monosodium salt of cyanuric acid, monohydrate (Rat: NOAEL ca. 154 mg/kg bw/day, male; NOAEL ca. 266 mg/kg bw/day, female; LOAEL ca. 371 mg/kg bw/day, male; LOAEL ca. 634 mg/kg bw/day, female).

5. Experimental results obtained with the substance monosodium salt of cyanuric acid (Mouse: NOAEL ca. 1523 mg/kg bw/day, male and NOAEL ca. 1582 mg/kg bw/day, female).

Justification for selection of repeated dose toxicity via oral route - systemic effects endpoint:
Chronic data is available (rats and mice). The NOAEL value obtained in the study with rats is considered for the effect level (lowest NOAEL).

Justification for classification or non-classification

No systemic toxicological findings could be detected after repeated administration of sodium cyanurate by the oral route.Therefore, a classification as STOT RE is not justified.