Naphthenic acids, nickel salts

Acute Toxicity: oral

Administrative data

Endpoint:

acute toxicity: oral

Type of information:

experimental study

Adequacy of study:

key study

Study period:

October 19, 2009 to November 9, 2009

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP Guideline Study

Cross-reference

Reason / purpose for cross-reference:

reference to same study

Data source

Reference

Reference 1

Reference Type:

study report

Title:

Unnamed

Year:

2009

Report date:

2009

Reference 2

Reference Type:

publication

Title:

Acute Oral Toxicity of Nickel Compounds

Author:

Henderson RG, Durando J, Oller A, Merkel DJ, Marone PA, and Bates HK.

Year:

2012

Bibliographic source:

Regul Toxicol and Pharmacol (doi.org/10.1016/j.yrtph.2012.02.002)

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 425 (Acute Oral Toxicity: Up-and-Down Procedure)

GLP compliance:

yes

Test type:

up-and-down procedure

Limit test:

yes

Test material

Test material information

Constituent 1

Reference substance name:

Nickel sulphate

EC Number:

232-104-9

EC Name:

Nickel sulphate

Cas Number:

7786-81-4

Molecular formula:

NiSO4

IUPAC Name:

nickel(2+) sulfate

Constituent 2

Reference substance name:

nickel (2+) sulfate

IUPAC Name:

nickel (2+) sulfate

Constituent 3

Reference substance name:

10101-97-0

IUPAC Name:

10101-97-0

Constituent 4

Reference substance name:

Nickel(II) sulfate hexahydrate

IUPAC Name:

Nickel(II) sulfate hexahydrate

Details on test material:

- Name of test material (as cited in study report): Nickel sulfate hexahydrate n56-72
- Physical state: solid
- Physical description: blue, crystalline
- Solubility: Soluble in water
- Stability under test conditions: Stable for the duration of testing
- Storage condition of test material: Stored in a closed container under nitrogen at room temperature
- Other: The test substance was stored in a closed container under nitrogen at room temperature. Prior to administration, the test substance was ground in a coffee mill (Cuisinart, Model #DCG-20). The sample was administered as a 45% w/w mixture in distilled water. Preliminary solubility testing conducted by EPSL indicated that mixtures in excess of 45% (i.e. 50-70%) were too viscous to be administered properly. Documentation of the methods of synthesis, fabrication, or derivation of the test substance is retained by Sigma Aldrich. 30S0 Spruce st. Saint Louis, MO 63103.

Test animals

Species:

rat

Strain:

other: Sprague-Dawley derived, albino

Sex:

female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Ace Animals, Inc., Boyertown, PA
- Age at study initiation: Young adult (10-11 weeks)
- Weight at study initiation: 182-230 grams

- Fasting period before study: Prior to each dosing, experimentaIIy naive rats were fasted overnight by removing the feed from their cages. During the fasting period, the rats were examined for health and weighed (initial).

- Housing: The animals were singly housed in suspended stainless steel caging with mesh floors, which conform to the size reconunendations in the most receut Guide for the Care and Use of LabamtOl)' Animals DHEW (NIH). Litter paper was placed beneath thc cage and was changed at least threc times per week.

- Diet (e.g. ad libitum): Purina Rodent Chow #5012
- Water (e.g. ad libitum): Filtered tap water was supplied ad libitum by an automatic water dispensing system
- Contanlinants: TIlere were no known contaminants reasonably expected to be found in the food or water at levels which would have interfered with the results of this study. Analyses of the food and water are conducted regularly and the records are kept on file at Eurofms I Product Safety Laboratories.

- Acclimation period: 6-22 days


ENVIRONMENTAL CONDITIONS
- Temperature (°C): 19-21'C
- Humidity (%): 34-69%
- Photoperiod (hrs dark / hrs light): 12-hour light/dark cycle

Administration / exposure

Route of administration:

oral: gavage

Vehicle:

water

Details on oral exposure:

VEHICLE
- Concentration in vehicle: 159, 200, and 250 mg/kg nickel sulfate hexahydrate
- Amount of vehicle (if gavage): Not provided

MAXIMUM DOSE VOLUME APPLIED: 250 mg/kg nickel sulfate hexahydrate

DOSE CALCULATIONS: Individual doses were calculated based on the initial body weights, taking into account the specific gravity (determined by EPSL) and concentration of the test mixture.

DOSAGE PREPARATION (if unusual): 159, 200, and 250 mg/kg nickel sulfate hexahydrate as a 45% w/w mixture in distilled water

DOSING: The ground test substance was administered to the stomach as a 45% w/w mixture in distilled water into the stomach using a stainless steel ball-tipped gavage needle attached to an appropriate syringe. FoIIowing administration, each animal was returned to its designated cage. Feed was
replaced approximately 3-4 hours after dosing. Individual animals were dosed as follows:

Limit test: 2,000 mg/kg (short-term outcome: death; long-term outcome: death)

Main test:
Dosing sequence 1: 159 mg/kg (short-term outcome: survival; long-term outcome: survival)
Dosing sequence 2: 200 mg/kg (short-term outcome: death; long-term outcome: death)
Dosing sequence 3: 159 mg/kg (short-term outcome: survival; long-term outcome: survival)
Dosing sequence 4: 200 mg/kg (short-term outcome: survival; long-term outcome: survival)
Dosing sequence 5: 250 mg/kg (short-term outcome: survival; long-term outcome: survival)

The test substance was administered in sequence to the animals as described above. The decision
to proceed with the next animal was based on the survival ofthe previous aninml following dosing. Dose progressions and stopping criteria were determined using the statistical program described later.

CLASS METHOD (if applicable)
- Rationale for the selection of the starting dose: A screen was conducted with one animal. An initial dose of 2,000 mg/kg was administered to one healthy female rat by oral gavage. Due to the mortality in this animal, a Main Test was conducted (see Amendment #1). Based on an estimate of the LD50 supplied by the Sponsor (200 mg/kg), five additional females were dosed at levels of 159, 200 or 250 mg/kg.

Doses:

159, 200, and 250 mg/kg nickel sulfate hexahydrate as a 45% w/w mixture in distilled water

No. of animals per sex per dose:

2 animals at 159 mg/kg
2 animals at 200 mg/kg
1 animal at 250 mg/kg

Control animals:

no

Details on study design:

- Duration of observation period following administration: 14 days (or other?) 14 days after dosing or until death occurred.

- Frequency of observations and weighing: Observed during first several hours post-dosing and at least once daily thereafter for 14 days after dosing or until death occurred. Individual body weights of the animals were recorded prior to test substance administration (initial) and again on Days 7 and 14 (temlination) foIl owing dosing or after death.

- Necropsy of survivors performed: Yes-Surviving rats were euthanized via CO2 inhalation at the end of the 14-day observation period. Gross necropsies were performed on all decedents and euthanized animals. Tissues and organs of the thoracic and abdominal cavities were examined.

- Other examinations performed: clinical signs, body weight,organ weights, histopathology, other: The animals were observed for mortality, signs of gross toxicity, behavioral changes. Observations included gross evaluation of skin and fur, eyes and mucous membranes, respiratory, circulatory, autonomic and central nervous systems, somatomotor activity and behavior pattern. Particular attention was directed to observation of tremors, convulsions, salivation, diarrhea, and coma.

Statistics:

The Acute Oral Toxicity (Guideline 425) Statistical Program (Weststat, version 1.0, May 2001)
was used for all data analyses including: dose progression selections, stopping criteria
determinations and/or LD50 and confidence limit calculations.

Results and discussion

Preliminary study:

Not applicable

Effect levels

Sex:

female

Dose descriptor:

LD50

Effect level:

361.9 mg/kg bw

Remarks on result:

other: 95% confidence interval cannot be calculated with any precision

Mortality:

159 mg/kg (0/2 females) - all survived; euthanized day 14
200 mg/kg (1/2 females) - one animal died within 5.5 hours of test substance administration; other animal survived and was euthanized on day 14
250 mg/kg (0/1 female) - the animal survived; euthanized day 14
2,000 mg/kg (1/1 female) - the animal died within 1.5 hours of test substance administration)

Clinical signs:

159 mg/kg (2 animals) - After administration, one animal exhibited piloerection, but this animal recovered by Day 1 and along with the other animal appeared active and healthy for the remainder 14-day observation period.

200 mg/kg (2 animals) - Prior to death, the decedent animal was hypoactive and exhibited prone posture. Following administration, the surviving animal exhibited piloerection, but recovered by six hours, appeared active and healthy for the remainder 14-day observation period.

250 mg/kg (1 animal)  - The animal appeared active and healthy during the study.

2,000 mg/kg (1 animal) - Prior to death, the animal was hypoactive and exhibited abnonnal posture.

Body weight:

159 mg/kg (2 animals) - both surviving animals gained body weight (1st animal: initial-230 grams, day 7-261 grams, and day 14-276 grams; 2nd animal: initial-200 grams, day 7-236 grams, and day 14-263 grams)

200 mg/kg (2 animals) -  surviving animal gained body weight (initial-220 grams, day 7-243 grams, and day 14-269 grams);no data for decedent
250 mg/kg (1 animal) - gained body weight (initial-200 grams, day 7-228 grams, and day 14-258 grams)
2,000 mg/kg (1 animal) - data not obtained due to death

Gross pathology:

159 mg/kg (2 animals) - No gross abnonnalities were noted for the animals when necropsied at the conclusion of the 14-day observation period.
200 mg/kg (2 animals) - Gross necropsy of the decedent revealed red intestines. No gross abnormalities were noted for the surviving animal when necropsied at the conclusion of the 14-day observation period
250 mg/kg (1 animal) - No gross abnormalities were noted for this animal when necropsied at the conclusion of the 14-day observation period.
2,000 mg/kg (1 animal) - Gross necropsy of the decedent revealed extremely red intestines.

Other findings:

None reported