Iridium

Endpoint summary

Description of key information

A GLP compliant study was performed to assess the acute oral toxicity of Iridium to the rat according to OECD guideline 420. Iridium was administered orally as a suspension in 1% Carboxymethylcellulose (CMC). Up to a dose level of 2000 mg/kg body weight, no mortality occured. It was concluded that the acute median lethal oral dose (LD₅₀) to rats was greater than 2000 mg/kg body weight.

Key value for chemical safety assessment

Acute toxicity: via oral route

Link to relevant study records

Reference

Endpoint:

acute toxicity: oral

Type of information:

experimental study

Adequacy of study:

key study

Study period:

8 Sept - 1 Oct 2020

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 420 (Acute Oral Toxicity - Fixed Dose Method)

Version / remarks:

v 17 December 2001

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method B.1 bis (Acute Oral Toxicity - Fixed Dose Procedure)

Version / remarks:

v 30 May 2008

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test type:

fixed dose procedure

Limit test:

no

Specific details on test material used for the study:

powder
purity >99.95%

Species:

rat

Strain:

Wistar

Sex:

female

Details on test animals or test system and environmental conditions:

Wistar Han
Females were nulliparous and non-pregnant
age at beginning of treatment: 8 - 12 weeks
Acclimatization:At least 5 days prior to the start of dosing under test conditions after health examination. Only animals without any visible signs of illness were used for the study.

Route of administration:

oral: gavage

Vehicle:

CMC (carboxymethyl cellulose)

Remarks:

1%

Details on oral exposure:

Dose administration was once orally by gavage (feeding needle). The volume administered did not exceed 10 mL/kg b.w.

Doses:

Based on available information on the toxicity of the test item, 300 mg/kg was chosen as the initial starting dose, since a severe toxicity which may necessitate humane euthanasia was not expected at this dose level.
In the absence of mortality or toxicity at a dose level of 2000 mg/kg, an additional group of animals was treated

No. of animals per sex per dose:

DRF: 1 female at 300 mg/kg, 1 female at 2000 mg/kg
Main test: 4 additional females at 2000 mg/kg

Control animals:

no

Details on study design:

Clinical observations and inspections for morbidity / mortality were performed at least three times within the first six hours after application (i.e., 30 minutes and 1 hour, 2 hours and 4 hours after dosing on day 0), thereafter at least once daily for 14 days. All surviving animals were observed for 14 days after dosing.
The nature and severity, where appropriate, of the clinical signs and the time were recorded at each observation for all individual animals. If applicable, the time of death/humane kill was recorded as precisely as possible. Observations included changes in the skin and fur, eyes and mucous membranes, and respiratory, circulatory, autonomic and central nervous system, and somatomotor activity and behavior pattern. Particular attention was directed to the observation of tremors, convulsions, salivation, diarrhea, lethargy, sleep and coma.
Body weights were recorded on Day 0 (prior to dosing), Day 7, and 14, or (if applicable) at death (unscheduled).
A gross necropsy was performed on all animals that died or were humanely killed during the study (if applicable) and at the end of the in-life part. Any macroscopic abnormalities were recorded. Routinely no organs or tissues were retained.

Statistics:

The test item is classified according to Annex 3 of the OECD Guidelines for Testing of Chemicals No. 420 ‘Acute Oral Toxicity – Fixed Dose Procedure’ (adopted 17 December 2001) as shown in the Flow Chart in Annex 2.
Evaluation of data includes the identification of the number of animals that died during the study (or that were killed for humane reasons), and determination of the nature, severity, onset and duration of the toxic effects. If possible, the signs of toxic effects of evident toxicity are described. Evident toxicity refers to the toxic effects of sufficient severity that administration of the next higher dose level could result in development of severe signs of toxicity and probable mortality. Effects on body weights and abnormalities noted at necropsy were identified.
Using the mortality data obtained, an estimate of the acute oral median lethal dose (LD50) of the test item was made.

Preliminary study:

Two single animals were treated as follows:
Dose level (mg/kg) Concentration (mg/mL) Dose volume (mL/kg) Number of rats
Female
300 30 10 1
2000 200 10 1

In the absence of mortality or toxicity at a dose level of 2000 mg/kg, an additional group of animals (4 females) was treated at 2000 mg/kg.

Key result

Sex:

female

Dose descriptor:

LD50

Effect level:

> 2 000 mg/kg bw

Based on:

test mat.

Mortality:

There were no deaths during the study.

Clinical signs:

other: 300 mg/kg: Clinical signs observed were secretion of Haderian glands on day 4 and 5. No further clinical signs were noted. 2000 mg/kg: Secretion of Harderian glands was noted in two animals. The fur of one animal was stained with the test item. Additiona

Gross pathology:

300 mg/kg: No abnormalities were noted at the macroscopic examination at study termination on Day 14.
2000 mg/kg: Small scratches in the scapula region were noted for three animals. One animal showed staining of the dorsum caused by secretion of Harderian glands. In four animals an increased amount of saliva in the mouth including a wet snout was observed. Two animals had a knot of size 3x4 mm on the thymus and for one animal a cystic kidney was noted. No other abnormalities were noted at necropsy.

Interpretation of results:

GHS criteria not met

Conclusions:

The acute median lethal oral dose (LD50) to rats of Iridium was demonstrated to be greater than 2000 mg/kg body weight.

Executive summary:

A study was performed to assess the acute oral toxicity of Iridium to the rat.

Following a sighting test at a dose levels of 300 mg/kg b.w. and 2000 mg/kg b.w. in one female rat per dose group, a further group of four fasted females was given a single oral dose of Iridium, as a suspension in 1% Carboxymethylcellulose (CMC), at a dose level of 2000 mg/kg body weight. Clinical signs and body weight development were monitored in all animals during the study. All animals were subjected to gross necropsy.

Mortality:There were no deaths.

Clinical Observations:Secretion of Harderian glands was noted (in one animal dosed at 300 mg/kg b.w. and two animals dosed at 2000 mg/kg b.w.) on several days. The fur of one animal (2000 mg/kg b.w.) was stained with test item on the day of application and for this animal a small scratch in the scapula region was observed. There were no signs of systemic toxicity noted in the remaining animals.

Body Weight:All animals showed expected gains in body weight.

Necropsy:Small scratches in the scapula region were noted in three animals. One animal showed staining of the dorsum caused by secretion of Harderian glands. In four animals an increased amount of saliva in the mouth including a wet snout was observed. Two animals had a knot of size 3x4 mm on the thymus and for one animal a cystic kidney was noted.No other abnormalities were noted at necropsy.

The acute median lethal oral dose (LD₅₀) to rats of Iridium was demonstrated to be greater than 2000 mg/kg body weight.

Iridium is not classified for acute toxicity (oral) according to CLP.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

LD50

Value:

2 000 mg/kg bw

Acute toxicity: via inhalation route

Endpoint conclusion

Endpoint conclusion:

no study available

Acute toxicity: via dermal route

Endpoint conclusion

Endpoint conclusion:

no study available

Justification for classification or non-classification

Iridium does not require classification for acute toxicity via the oral route, according to GLP.