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Toxicological information

Repeated dose toxicity: oral

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Administrative data

Endpoint:
sub-chronic toxicity: oral
Type of information:
migrated information: read-across based on grouping of substances (category approach)
Adequacy of study:
key study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Study performed according to basic scientific principles.

Data source

Referenceopen allclose all

Reference Type:
publication
Title:
Safety of polysodium silicate. Subacute peroral toxicity in rats.
Author:
Ito, R. et al.
Year:
1975
Bibliographic source:
J. Med. Sac. Toho. Japan 22(2), 223-227
Reference Type:
secondary source
Title:
Soluble Silicates. CAS No. 1344-09-8, 6834-92-0, 10213-79-3, 13517-24-3 and 1312-76-1.
Author:
OECD SIDS
Year:
2004
Bibliographic source:
SIDS Initial Assessment Report for SIAM 18 Paris, France 20-23 April, 2004

Materials and methods

Test guideline
Qualifier:
equivalent or similar to
Guideline:
OECD Guideline 408 (Repeated Dose 90-Day Oral Toxicity in Rodents)
Deviations:
not specified
GLP compliance:
no
Limit test:
no

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
SOURCE: Nihon Nohyaku Co., Ltd
PURITY: Not reported
IMPURITY/ADDITIVE/ETC.: Not reported
ANY OTHER INFORMATION: Poly sodium silicate is assumed to be metasilicate (designated in tables and figures as 'meta silicate' and in the text as Na2O.SiO2, indicating a molar ratio of 1.0). Designated by authors as Porikuron, a product based on poly sodium silicate (Na2O.nSiO2).

Test animals

Species:
rat
Strain:
Wistar
Sex:
male/female
Details on test animals and environmental conditions:
TEST ORGANISMS
- Age: 7 weeks

Administration / exposure

Route of administration:
oral: drinking water
Vehicle:
water
Analytical verification of doses or concentrations:
not specified
Duration of treatment / exposure:
3 months
Frequency of treatment:
daily
Doses / concentrations
Remarks:
Doses / Concentrations:
200, 600 and 1800 ppm
Basis:
nominal in water
No. of animals per sex per dose:
5
Control animals:
yes

Examinations

Observations and examinations performed and frequency:
- Clinical signs: daily
- Mortality: daily
- Body weight: once a week
- Food consumption: once a week
- Water consumption: measured daily 
- Haematology: after the test period erythrocytes and leukocytes were counted, hemoglobin value, blood cell volume and leukocyte percentage
- Biochemistry:  after the test period gamma-GOT, gamma-GPT and alkali phosphatase activity measurement
- Urinalysis: after the test period measurements were made on pH-value, sugar, protein, ketone and blood value.
Sacrifice and pathology:
- Macroscopic: wet weight of liver, kidney, heart, lung, spleen, suprarenal glands, thymus, thyroid gland, testicles and ovaries. Also dissected: pancreas, intestines, stomachs, bone marrow.
- Microscopic: liver, kidney, heart, lung, spleen, suprarenal glands, thymus, thyroid gland, testicles and ovaries were fixed with 10% formalin, packed in paraffin, cut into thin sections and subjected to hematoxylin and eosin staining.

Results and discussion

Effect levels

Dose descriptor:
NOAEL
Effect level:
> 227 - 237 mg/kg bw/day (nominal)
Sex:
male/female
Basis for effect level:
other: overall effects

Target system / organ toxicity

Critical effects observed:
not specified

Any other information on results incl. tables

No clearly treatment related effects at tested dose levels of 200, 600 and 1800 ppm (corresponding to 26.4, 76.2 and
227.1 mg/kg/day, respectively, for males; and 32.1, 97.6 and 237.2  mg/kg/day, respectively, for females).


TOXIC RESPONSE/EFFECTS BY DOSE LEVEL: 
- Mortality and time to death: None
- Clinical signs: No effects
- Body weight gain: No effects
- Food/water consumption: No effects
- Clinical chemistry: No effects
- Haematology: No effects
- Urinalysis: No effects
- Organ weights: No effects
- Gross pathology: No effects
- Histopathology: Except for the kidneys, no morphological changes have  been observed in the organs examined. The observed

histological changes in the kidneys (tubule wall calcinosis, glomerular swelling, tubule  swelling, weakening of the renal tubule cell

walls and dilation of the  tubule lumen) were not dose-related and occurred also in the controls.  Cylindrical inclusions in the renal

tubular cells were only observed in  the medium dosage group.

Applicant's summary and conclusion