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Description of key information

Oral LD50 for rhenium (VII) oxide in female rat > 500 - < 2000 mg/kg bw.

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:
25 February 2003 – 18 June 2003
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: Study conducted according to OECD Guideline No. 423, EEC Directive 96/54/EC and USEPA Guideline OPPTS 870.1100.
Qualifier:
according to guideline
Guideline:
OECD Guideline 423 (Acute Oral toxicity - Acute Toxic Class Method)
Deviations:
no
Qualifier:
according to guideline
Guideline:
EU Method B.1 tris (Acute Oral Toxicity - Acute Toxic Class Method)
Deviations:
no
Qualifier:
according to guideline
Guideline:
EPA OPPTS 870.1100 (Acute Oral Toxicity)
Deviations:
no
GLP compliance:
yes (incl. QA statement)
Test type:
acute toxic class method
Limit test:
no
Species:
rat
Strain:
other: Wistar CrIGIxBrIHan:Wl
Sex:
female
Details on test animals or test system and environmental conditions:
TEST ANIMALS
- Source: Charles River Deutschland GmbH, Sandhofer Weg 7, 97633 Sulzfeld
- Age at study initiation: Young adult animals (approx . 14-18 weeks)
- Weight at study initiation: 194-214 g
- Fasting period before study: Feed withdrawn at least 16 hours before administration, but water available ad libitum .
- Housing: 1 rat / Stainless steel wire mesh cage (type DK-111, Becker & Co., Castrop-Rauxel, FRG )
- Diet: ad libitum (Kliba-Labordidt, Provimi Kliba SA, Kaiseraugst, Switzerland)
- Water: ad libitum
- Acclimation period: at least 5 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 20-24
- Humidity (%): 30-70
- Air changes (per hr): fully air-conditioned rooms
- Photoperiod (hrs dark / hrs light): 6 am – 6 pm light, 6 pm – 6 am darkness


Route of administration:
oral: gavage
Vehicle:
water
Details on oral exposure:
VEHICLE
- Concentration in vehicle: 5 or 20 g/100 ml
- Amount of vehicle (if gavage): 10 ml/kg bw
- Justification for choice of vehicle: Aqueous formulation corresponds to the physiological medium
- Purity: Doubly distilled

MAXIMUM DOSE VOLUME APPLIED: 10 ml/kg bw

CLASS METHOD (if applicable)
- Rationale for the selection of the starting dose: Based on the physical and chemical characteristics of the test substance and its composition, no pronounced acute oral toxicity was expected. Therefore, a starting dose of 2,000 mg/kg bw was chosen in the first step with 3 female animals. As one of those animals died, 2,000 mg/kg bw was administered to a further 3 female animals in a second step. Because all animals died at the second step, 500 mg/kg bw was tested in a third step with 3 female animals. Because all animals survived the third step, 500 mg/kg bw was again tested in a fourth step with another group of 3 female animals.

Doses:
500 or 2000 mg/kg bw
No. of animals per sex per dose:
Six females/dose
Control animals:
no
Details on study design:
- Duration of observation period following administration: at least 14 days
- Frequency of observations and weighing: Signs and symptoms of toxicity recorded several times on the day of administration and at least once each workday. Mortality checked twice
each workday and once on Saturdays, Sundays and public holidays. Body weights measured shortly before administration, weekly thereafter and at the end of the study period.
- Necropsy of survivors performed: yes
- Other examinations performed: clinical signs, body weight, gross pathology

Statistics:
No data
Sex:
female
Dose descriptor:
LD50
Effect level:
> 500 - < 2 000 mg/kg bw
Mortality:
No mortality occurred at 500 mg/kg bw. Four of the six animals given 2000 mg/kg bw died between 1 and 3 days after administration.
Clinical signs:
other: At 500 mg/kg bw, impaired general state, dyspnoea and staggering were observed in all of the treated animals with a poor general state, piloerection, smeared fur and lacrimation being seen in one animal, the symptoms being evident from immediately after a
Gross pathology:
There were no macroscopic abnormalities amongst the animals given 500 mg/kg bw. Amongst those administered 2000 mg/kg bw, those which died showed a moderate postmortal state and yellow discoloration, few or many black erosions/ulcers of the glandular stomach and a red, diffuse discoloration of the small and large intestine. Amongst the survivors, a severe thickening of the wall of the glandular stomach was found.
Interpretation of results:
Toxicity Category IV
Remarks:
Migrated information Criteria used for interpretation of results: EU
Conclusions:
The acute oral median lethal dose (LD50) of rhenium (VII) oxide in the female rat was found to be >500 mg/kg bw and <2000 mg/kg bw.
Executive summary:

In a guideline acute oral toxicity study, conducted to GLP, groups of 6 female rats were administered 500 or 2000 mg rhenium (VII) oxide/kg bw by stomach tube and observed for at least 14 days. Clinical signs of toxicity appeared immediately following administration and lasted for up to 9 days. Deaths amongst the high-dosed animals were recorded between 1 and 3 days after dosing. Body weight amongst this group was decreased and gross pathological examination revealed effects on the stomach and intestines.The acute oral median lethal dose (LD50) was deemed to be >500 mg/kg bw and <2000 mg/kg bw.

Endpoint conclusion
Endpoint conclusion:
adverse effect observed

Acute toxicity: via inhalation route

Endpoint conclusion
Endpoint conclusion:
no study available

Acute toxicity: via dermal route

Endpoint conclusion
Endpoint conclusion:
no study available

Additional information

A guideline acute oral toxicity study, conducted to GLP, on the relevant material rhenium (VII) oxide, determined the LD50 to be > 500 mg/kg bw and < 2000 mg/kg bw. On the basis of this, it is considered appropriate to classify Perrhenic acid as Acute tox category 4.


Justification for selection of acute toxicity – oral endpoint
Only one, good quality, guideline study on a relevant material.

Justification for classification or non-classification