Synthetic amorphous magnesium silicate, with molar ratio (SiO2:MgO) range of 1.4-4

Acute Toxicity: oral

Administrative data

Endpoint:

acute toxicity: oral

Type of information:

experimental study

Adequacy of study:

key study

Study period:

11 August 2000 to 25 August 2000

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Cross-reference

Reason / purpose for cross-reference:

reference to same study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1989

Report date:

2000

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

EPA OPPTS 870.1100 (Acute Oral Toxicity)

Principles of method if other than guideline:

Conducted according to standard acute oral toxicity study protocol

GLP compliance:

yes

Test type:

standard acute method

Limit test:

yes

Test material

Test material information

Constituent 1

Reference substance name:

Synthetic amorphous magnesium silicate, with molar ratio (SiO2:MgO) range of 1.4-4

EC Number:

701-065-4

Molecular formula:

MgO.xSiO2, the molar ratio SiO2:MgO typically ranges from 1.4-4

IUPAC Name:

Synthetic amorphous magnesium silicate, with molar ratio (SiO2:MgO) range of 1.4-4

Specific details on test material used for the study:

The test material was a white powder identified as Magnesol, Grade HMR-LS, S.R.R.000-21-1. This grade is within the identifiers of the registered substance.

Test animals

Species:

rat

Strain:

Sprague-Dawley

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source:Harlan Sprague Dawley, Indianapolis, Indiana.
- Age at study initiation: 6 to 10 weeks old
- Weight at study initiation: 204-251 grams
- Housing: Housed individually in stainless steel cages
- Diet: Purina Rat Chow available ad libitum
- Water: available ad libitum
- Acclimation period: five days prior to treatment

ENVIRONMENTAL CONDITIONS
The rats were housed in a temperature, humidity and light controlled room.

Administration / exposure

Route of administration:

oral: gavage

Vehicle:

water

Details on oral exposure:

The test substance was administered orally to animals, fasted overnight, five male/five female per dose group, according to the individual body weights.

Doses:

A dose of 5 g/kg was administered via a metal dosing cannula. The material was prepared as a 33% suspension in distilled water and administered in a dose volume of 15 mL/kg bw

No. of animals per sex per dose:

Five males and five females per dose group.

Control animals:

no

Details on study design:

All test animals were observed frequently during the day of dosing and once daily for 14 days following dosing for any toxic or deleterious effects. Body weights were recorded prior to first dosing occasion and at 7 and 14 days post administration. A group of 5 males and 5 females was treated at the limit dose level of 5 g/kg. No further dose levels were tested since no mortalities occurred. At the end of the observation period all test animals were sacrificed by CO2 asphyxiation. Gross necropsy was conducted on all the animals.

Statistics:

Not applicable

Results and discussion

Effect levels

Sex:

male/female

Dose descriptor:

LD50

Effect level:

> 5 000 mg/kg bw

Mortality:

The administration of Magnesol by oral gavage at a dose of 5 g/kg body weight to male and female rats produced no mortality in the ten test animals.

Clinical signs:

other: No clinical signs recorded

Gross pathology:

There were no macroscopic abnormalities or gross changes observed during necropsy.

Other findings:

No data

Any other information on results incl. tables

Rat Number	Sex	Initial Bwt (gm)	Dose (g/kg)	Dose in grams	7 Day Bwt (gm)	14 Day Bwt (gm)	Fate
670	M	238	5.0	1.19	277	316	Survived
671	M	246	5.0	1.23	293	330	Survived
672	M	247	5.0	1.24	301	344	Survived
673	M	251	5.0	1.26	298	332	Survived
674	M	242	5.0	1.21	293	335	Survived
675	F	209	5.0	1.05	220	250	Survived
676	F	205	5.0	1.03	219	230	Survived
677	F	204	5.0	1.02	221	235	Survived
678	F	223	5.0	1.12	242	263	Survived
679	F	225	5.0	1.13	250	268	Survived

Applicant's summary and conclusion

Interpretation of results:

GHS criteria not met

Conclusions:

The acute oral LD50 was greater than the limit dose of 5000 mg/kg.

Executive summary:

A sample identified as Magnesol, Grade HMR-LS was administered by gavage at a dose of 5.0 g/kg body weight to five male and five female rats. There was no mortality at the 5.0 g/kg dose level during the 14 day observation period. The acute oral LD50 was determined to be greater than 5000 mg/kg.

No classification is required for magnesium silicate under CLP based on the results of the acute study with Magnesol,