Ruthenium trichloride hydrate

Endpoint summary

Description of key information

In an OECD Test Guideline 407 repeated dose oral toxicity study, rats were fed diets containing 0, 500, 1500, 5000 or 15,000 ppm ruthenium trichloride hydrate for 28 days. Males in the highest dose group had reduced body weight gain and reduced food conversion efficiency compared to controls. There were no other adverse effects in these animals, and no effects on clinical signs, pathology, organ weights or histopathology in any treated animals. The study NOAEL was 5000 ppm (equivalent to about 407 mg/kg bw/day) (Zelenák, 2017).

 

No repeated dose toxicity studies by the inhalation or dermal route were identified, or are required.

Key value for chemical safety assessment

Repeated dose toxicity: via oral route - systemic effects

Link to relevant study records

Reference

Endpoint:

short-term repeated dose toxicity: oral

Type of information:

experimental study

Adequacy of study:

key study

Study period:

14 July 2016-28 February 2017

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Remarks:

Study conducted according to GLP

Qualifier:

according to guideline

Guideline:

OECD Guideline 407 (Repeated Dose 28-Day Oral Toxicity Study in Rodents)

Version / remarks:

03 October 2008

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Limit test:

no

Species:

rat

Strain:

Wistar

Details on species / strain selection:

Wistar rat as a rodent is one of the standard strains for repeat-dose toxicity studies.

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River Laboratories, Research Models and Services, Germany GmbH, Sandhofer Weg 7, D-97633, Sulzfeld, Germany.
- Females (if applicable) nulliparous and non-pregnant: Yes.
- Age at study initiation: Approximately 8 weeks old at onset of treatment.
- Weight at study initiation: Males: 283-347 g. Females: 191-249 g. Weight did not exceed +/- 20% of mean weight at onset of treatment.
- Fasting period before study: Not specified.
- Housing: Type II polycarbonate/ wire grid bottomed cages. Animals were housed two or three per cage.
- Diet (e.g. ad libitum): ssniff® SM R/M-Z+H “Complete Diet for Rats and Mice- Breeding and Maintenance” (ssniff Spezialdiäten GmbH, D-59494 Soest Germany), with or without Ruthenium chloride (treated or control groups, respectively) provided ad libitum.
- Water (e.g. ad libitum): Tap water provided ad libitum.
- Acclimation period: 15 days.

DETAILS OF FOOD AND WATER QUALITY: Tap water as for human consumption, assessed once every three months, with monthly microbiological assessment.

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 20.3 - 27.4 °C
- Humidity (%): 33 - 78%
- Air changes (per hr): 15-20.
- Photoperiod (hrs dark / hrs light): 12 hours artificial light (6am - 6pm). 12 hours dark.

IN-LIFE DATES: From: 30 June 2016 (animal arrival) To: 25 August 2016 (last necropsy).

Route of administration:

oral: feed

Details on oral exposure:

DIET PREPARATION
- Rate of preparation of diet (frequency): A single diet mix batch was prepared before the study.
- Mixing appropriate amounts with (Type of food): About 6 minutes for pre-mixing and 4-8 minutes for diet mixing.
- Storage temperature of food: approximately 15-21 °C (storage areas); 22 +/- 3 °C (animal rooms).

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

Analysis of the diets for homogeneity and concentration of Ruthenium chloride were performed at the Test Site using a validated ICP/AES method to determine the Ruthenium content.

Duration of treatment / exposure:

28 days.

Frequency of treatment:

Constant (dietary).

Dose / conc.:

0 ppm

Remarks:

Control, received diet prepared in a similar manner to treatment groups, without inclusion of test material.

Dose / conc.:

500 ppm

Remarks:

"Low dose" group. Approximately 40.6 mg/kg bw/day.

Dose / conc.:

1 500 ppm

Remarks:

"Mid dose" group. Approximately 124 mg/kg bw/day.

Dose / conc.:

5 000 ppm

Remarks:

"Mid high dose" group. Approximately 407 mg/kg bw/day.

Dose / conc.:

15 000 ppm

Remarks:

"High dose" group. Approximately 1238 mg/kg bw/day.

No. of animals per sex per dose:

5/sex/group (low and mid doses); 10/sex/group (control, mid high and high doses).

Control animals:

yes, plain diet

Details on study design:

- Dose selection rationale: The concentrations of Ruthenium chloride in diet were selected based on the available data and information from a preliminary dose range finding study [CiToxLAB study code 15/266-100PE].
- Rationale for animal assignment (if not random): Randomisation based on body weights.
- Post-exposure recovery period in satellite groups: 5/sex/group, 28-day daily treatment with control, mid high or high dose. 14-day recovery period.
- Section schedule rationale (if not random): Not specified.

Positive control:

None.

Observations and examinations performed and frequency:

CAGE SIDE OBSERVATIONS: Yes.
- Time schedule: At least once a day, at approximately the same time. Animals were inspected for signs of morbidity and mortality twice daily (at the beginning and end of each day).
- Cage side observations: Not specified.

DETAILED CLINICAL OBSERVATIONS: Yes.
- The animals were monitored for any clinical signs, including pertinent behavioural changes, signs of toxicity including mortality, changes in skin, fur, eyes, mucous membranes, occurrence of secretions and excretions, and autonomic activity (e.g. lachrymation, piloerection, pupil size, unusual respiratory pattern), changes in gait, posture and response to handling as well as the presence of clonic or tonic movements, stereotypies (e.g. excessive grooming, repetitive circling), bizarre behaviour (e.g. selfmutilation, walking backwards), observation of tremors, convulsions, salivation,
diarrhoea, lethargy, sleep or coma.

BODY WEIGHT: Yes.
- Time schedule for examinations: 7 days prior to treatment start (Day -7), then daily until the first day of treatment (Day 0). Twice weekly thereafter, including before necropsy.

FOOD CONSUMPTION AND COMPOUND INTAKE (if feeding study):
- Food consumption for each animal determined and mean daily diet consumption calculated as g food//day: Yes (by measuring non-consumed diet on a regular basis throughout the study).
- Compound intake calculated as time-weighted averages from the consumption and body weight gain data: Yes.

FOOD EFFICIENCY:
- Mean food utilisation (food conversion efficiency) was calculated: weekly body weight gain (g)/weekly food consumption (g).

WATER CONSUMPTION AND COMPOUND INTAKE (if drinking water study): Not specified.

OPHTHALMOSCOPIC EXAMINATION: No.

HAEMATOLOGY: Yes.
- Time schedule for collection of blood: Post-fasting and immediately prior to the scheduled necropsy (Day 28).
- Anaesthetic used for blood collection: Yes (pentobarbital).
- Animals fasted: Yes.
- How many animals: All animals.
- Parameters checked in table 1 were examined.

CLINICAL CHEMISTRY: Yes.
- Time schedule for collection of blood: Post-fasting and immediately prior to the scheduled necropsy (Day 28).
- Animals fasted: Yes.
- How many animals: All animals.
- Parameters checked in table 2 were examined.

URINALYSIS: No.

NEUROBEHAVIOURAL EXAMINATION: Yes.
- Time schedule for examinations: Day 21/22 of test.
- Dose groups that were examined: All animals.
- Battery of functions tested: sensory activity / grip strength.

IMMUNOLOGY: No.

Sacrifice and pathology:

GROSS PATHOLOGY: Yes (all tissues and organs).

HISTOPATHOLOGY: Yes (see table 3). Tissues and organs in Table 3 were retained from all animals. Full histopathology was performed for control and high dose animals, as well as any organs or tissues from other animals with macroscopic abnormalities.

Statistics:

The mean and standard deviations values, for the frequency of treatment-related clinical observations and macroscopic findings were calculated.

Clinical signs:

effects observed, non-treatment-related

Description (incidence and severity):

Dark faeces was observed in the mid high (5000 ppm) and high dose (15,000 ppm) animals from Day 11 to Day 30. This was considered to be a non-adverse observation. No signs of toxicity were observed.

Mortality:

no mortality observed

Body weight and weight changes:

effects observed, treatment-related

Description (incidence and severity):

At completion of the feeding period (Day 27), the mean body weight gain of high dose (15,000 ppm) males was about 23% lower than controls. After a 14-day recovery period, these changes were completely recovered. No dose-related or statistically significant changes in body weight gain were observed in the other treated males, or any treated females. The mean body weight and body weight gain of females was more variable than for the males, but there was no clear evidence of a treatment-related effect.

Food consumption and compound intake (if feeding study):

no effects observed

Food efficiency:

effects observed, treatment-related

Description (incidence and severity):

Statistically significantly lower (about 24%) food utilisation was observed in high dose (15,000 ppm) males dues to reduced body weight gain. No effects in other treated males or any treated females.

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):

no effects observed

Immunological findings:

not examined

Organ weight findings including organ / body weight ratios:

no effects observed

Gross pathological findings:

no effects observed

Neuropathological findings:

not examined

Histopathological findings: non-neoplastic:

no effects observed

Histopathological findings: neoplastic:

no effects observed

Other effects:

not specified

Key result

Dose descriptor:

NOAEL

Effect level:

5 000 ppm

Based on:

test mat.

Sex:

male/female

Basis for effect level:

body weight and weight gain

Critical effects observed:

not specified

Conclusions:

In an OECD 407-compliant 28-day repeated-dose oral toxicity study, rats were fed diets containing 0, 500, 1500, 5000 or 15,000 ppm ruthenium trichloride hydrate (providing up to approximately 1238 mg/kg bw/day). Males in the highest dose group had reduced body weight gain and reduced food conversion efficiency compared to controls. There were no other adverse effects in these animals, and no effects on clinical signs, pathology, organ weights or histopathology in any treated animals. Consequently, the NOAEL is 5000 ppm (providing approximately 407 mg/kg bw/day).

Executive summary:

In an OECD 407 repeated-dose oral toxicity study, conducted according to GLP, groups of Wistar rats were fed diets containing ruthenium trichloride hydrate for 28 days. Diets were formulated to provide 0, 500, 1500, 5000 or 15,000 ppm of the test material (equivalent to approximately 0, 40.6, 124, 407 or 1238 mg/kg bw/day). Male rats recieving the highest dietary concentration (15,000 ppm, approximately 1238 mg/kg bw/day) showed reduced body weight gain compared to controls. These animals also demonstrated a statistically significant reduction in food conversion efficiency. No other significant differences in body weight or body weight gain were reported, although high dose females showed lower body weight gain for the first week only.

There were no adverse effects on food consumption, clinical signs of toxicity, behaviour (functional neurological assessment), haematology, clinical biochemistry, gross pathology, organ weights or histopathology.

The no-observed-adverse-effect level (NOAEL) of ruthenium trichloride hydrate in rats following dietary exposure was 5000 ppm (approximately 407 mg/kg bw/day), on the basis of reduced body weight gain in treated males.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

NOAEL

407 mg/kg bw/day

Study duration:

subacute

Species:

rat

Quality of whole database:

Overall, good-quality database which meets REACH Standard Information Requirements.

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

Mode of Action Analysis / Human Relevance Framework

No data identified.

Additional information

No relevant human data were identified.

 

In an OECD Test Guideline 407 repeated dose oral toxicity study, conducted according to GLP, Wistar rats (5/sex/group) were fed ruthenium trichloride hydrate at concentrations of 0, 500, 1500, 5000 or 15,000 ppm (equivalent to approximately 0, 40.6, 124, 407 or 1238 mg/kg bw/day) for 28 days. Male rats fed the highest dietary concentration showed reduced body weight gain compared to controls. These animals also demonstrated a statistically significant reduction in food conversion efficiency. No other significant differences in body weight or body weight gain were reported, although high dose females showed reduced growth for the first week only. There were no adverse effects on food consumption, clinical signs of toxicity, behaviour (functional neurological assessment), haematology, clinical biochemistry, gross pathology, organ weights or histopathology. The no-observed-adverse-effect level (NOAEL) of ruthenium trichloride in rats after 28 days' administration in the diet was 5000 ppm (approximately 407 mg/kg bw/day), on the basis of reduced body weight gain in treated males. On this basis, a study NOAEL of 5000 ppm (about 407 mg/kg bw/day) was established (Zelenák, 2017).

 

In an OECD Test Guideline 421 reproductive and developmental toxicity screening study involving dietary exposure to ruthenium trichloride hydrate at up to 15,000 ppm for at least 29 days, the systemic NOAEL was 5000 ppm (419 mg/kg bw/day), based on reduced growth in males at the highest tested dose (Hargitai, 2017).

 

According to REACH Annex VIII (EC 1907/2006), repeated dose toxicity studies only need to be conducted on one species taking into consideration the most appropriate route of administration regarding human exposure.

Justification for classification or non-classification

No adverse systemic effects were seen in reliable guideline studies (28-day oral repeated dose and a reproductive/developmental screening assay) with ruthenium trichloride hydrate at more than 400 mg/kg bw/day. As such, the results of these studies indicate that classification of this substance as STOT-RE is not required, according to EU CLP criteria (EC 1272/2008).