Nickel bis(2-ethylhexanoate)

Acute Toxicity: oral

Administrative data

Endpoint:

acute toxicity: oral

Type of information:

experimental study

Adequacy of study:

key study

Study period:

07 July 2022 - 26 July 2022

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2022

Report date:

2022

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 423 (Acute Oral toxicity - Acute Toxic Class Method)

GLP compliance:

yes (incl. QA statement)

Test type:

acute toxic class method

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

Nickel bis(2-ethylhexanoate)

EC Number:

224-699-9

EC Name:

Nickel bis(2-ethylhexanoate)

Cas Number:

4454-16-4

Molecular formula:

C8H16O2.1/2Ni

IUPAC Name:

nickel(2+) bis(2-ethylhexanoate)

Test material form:

solid

Remarks:

dark green paste

Details on test material:

Supplier: Shepherd Mirecourt S.A.S.
CAS Number: 4454-16-4
Batch/Lot number: L8147
Appearance: dark green paste
Purity: ≥94%
Ni content: 15.82 %
Expiry date: 17 November 2022

Test animals

Species:

rat

Strain:

Wistar

Remarks:

Han:WIST rats

Sex:

female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Toxi-Coop Zrt., H-1122 Budapest, Magyar Jakobinusok tere 4B
- Hygienic level at supplier: SPF
- Hygienic level during the study: Standard housing conditions
- Number of animals: 9 animals, 3 animals/group
- Sex: Female, nulliparous and non-pregnant animals
- Age of animals at dosing: Young adult rats, approx. 8 weeks old
- Body weight range at dosing: 170 - 184 g. The maximum difference of individual animal weights from the mean of the treatment group did not exceed 20%.
- Acclimatisation period: At least 15 days
- Animal health: Only healthy animals were used for the test. The health status was certified by the Veterinarian.
- Housing: Group caging (3 animals/cage)
- Cage type: T3H polycarbonate
- Bedding and nesting: “SAFE 3/4-S-FASERN” certified wooden chips and “Sizzle pet” nest material were available to animals during the study.
- Enrichment: Animals were housed by group to allow social interaction and with deep wood sawdust bedding to allow digging and other normal rodent activities.
- Animals received standard laboratory rat diet, ad libitum, and tap water from the municipal supply, as for human consumption from drinking bottles designed for rodents, ad libitum.
- The night before treatment, the animals were fasted. Food, but not water, was withheld overnight. Animals were weighed before dosing. Food was replaced 3 hours after the treatment.

ENVIRONMENTAL CONDITIONS
- Lighting period: 12 hours daily, from 6.00 a.m. to 6.00 p.m.
- Temperature: 19 – 24 °C (target: 22 ± 3 °C)
- Relative humidity: 34 – 70 % (target: 30 – 70 %)
- Ventilation: 15-20 air exchanges/hour

IN-LIFE DATES: From 07 July 2022 to 26 July 2022

Administration / exposure

Route of administration:

oral: gavage

Vehicle:

corn oil

Remarks:

Batch number: MKCM9808 Manufacturer: Sigma-Aldrich Expiry date: 30 April 2026 Storage: Room temperature

Details on oral exposure:

VEHICLE
- Concentration in vehicle: 200 or 30 mg/mL
- Amount of vehicle (if gavage): 10 mL/kg bw
- Justification for choice of vehicle: The test item did not dissolve in distilled water, in 1% methyl cellulose solution and in PEG 400 (even if heated up to approximately 60º C), and dissolved partially in corn oil.
Because the best results were achieved in corn oil, a harsher mechanical treatment was chosen: the sonication (with a 1.3mm disruption horn) of the test item with corn oil resulted in a gavage-applicable clear solution of green color.

DOSAGE PREPARATION: The test item was freshly formulated in the vehicle at the appropriate concentration (200 or 30 mg/mL), in the Pharmacy of NEXTREAT Laboratories on the day of administration. The formulations were stirred with magnetic stirrer up to finishing the treatment.

CLASS METHOD (if applicable)
- Rationale for the selection of the starting dose: As starting dose level for acute toxicity study, a dose of 2000 mg/kg body weight (bw) was selected based on the information published by ECHA.
- Initially three animals were treated at the starting dose of 2000 mg/kg bw (Group 1). All three animals died on Day 0, thus the second group (Group 2) was treated at the lower dose level (300 mg/kg bw). As no mortality observed after approximately 24 hours, three further animals were treated at the same dose level (Group 3). As no mortality was observed in this confirmatory dose group, no further animals were treated according to the study design of OECD 423.

Doses:

2000 mg/kg bw or 300 mg/kg bw

No. of animals per sex per dose:

3 female animals per group

Control animals:

no

Details on study design:

- Duration of observation period following administration: 14 days
- Clinical observations: Following the end of the dosage, the animals were observed individually once during the first 30 minutes, at 1, 2, 3, 4 and 6 hours after the treatment and once daily for 14 consecutive days thereafter. Individual observations were performed on the skin and fur, eyes and mucous membranes and also respiratory, circulatory, autonomic and central nervous system, somatomotor activity and behaviour pattern. Particular attention was directed to observation of tremors, convulsions, salivation, diarrhoea, lethargy, sleep and coma. The time of death was recorded as precisely as possible.
- Body weight: The body weight of the animals was recorded on Days 0 (prior to dosing), 7 and 14 (prior to necropsy), with a precision of 1 g. Terminal body weight of animals found dead was also recorded.
- Necropsy: Animals were subjected to a necropsy and a macroscopic examination. After examination of the external appearance, the cranial, thoracic and abdominal cavities were opened and the appearance of the tissues and organs were observed. All gross macroscopic changes were recorded for each animal.

Statistics:

The method used was not intended to allow the calculation of a precise LD50 value.

Results and discussion

Effect levels

Effect levels 1

Key result

Sex:

female

Dose descriptor:

LD50

Effect level:

> 300 - <= 2 000 mg/kg bw

Based on:

test mat.

Effect levels 2

Sex:

female

Dose descriptor:

LD50 cut-off

Effect level:

500 mg/kg bw

Based on:

test mat.

Mortality:

At the dose level of 2000 mg/kg bw, 3/3 animals died on Day 0.
No mortality was observed at the dose level of 300 mg/kg bw.

Clinical signs:

other: other:

Body weight:

lower than 10% body weight loss

Gross pathology:

In the 2000 mg/kg bw groups, three animals were found dead on Day 0. In these animals diffuse red discoloration of the glandular mucosa of the stomach was observed. Green mucoid material in the stomach and non-collapsed lungs were also noted in all animals.

In the 300 mg/kg bw group, no macroscopic changes were observed.

Applicant's summary and conclusion

Interpretation of results:

Category 4 based on GHS criteria

Remarks:

The test substance is classified Category 4 according to Regulation (EC) No 1272/2008 (CLP)

Conclusions:

Under the conditions of this study, the acute oral LD50 value of the test item Nickel-2-ethylhexanoate was found to be between 300 and 2000 mg/kg bw in female Han:WIST rats.
The LD50 cut-off value is 500 mg/kg bw.

The study result triggers the following classification/labelling:
- Regulation (EC) No 1272/2008 (CLP): Category 4
- GHS (rev. 9) 2021: Category 4