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Diss Factsheets

Administrative data

Description of key information

Disodium silicate is corrosive to skin and eyes. The degree of irritation is dependent on the concentration (and water content).

Key value for chemical safety assessment

Skin irritation / corrosion

Link to relevant study records

Referenceopen allclose all

Endpoint:
skin irritation: in vivo
Type of information:
experimental study
Adequacy of study:
other information
Reliability:
4 (not assignable)
Rationale for reliability incl. deficiencies:
other: Only secondary literature available (review).
Principles of method if other than guideline:
Method: other: FHSA method 16 C.F.R. 1500.41 et.seq.
GLP compliance:
no
Species:
rabbit
Type of coverage:
occlusive
Amount / concentration applied:
Concentration: 10 T49-004:wt%
Duration of treatment / exposure:
24 hour(s)
Irritation parameter:
primary dermal irritation index (PDII)
Score:
5.6

RS-Freetext:
AVERAGE SCORE: Not reported
REVERSIBILITY: Not reported
OTHER EFFECTS: Not reported

Interpretation of results:
corrosive
Endpoint:
skin irritation: in vivo
Type of information:
experimental study
Adequacy of study:
other information
Reliability:
4 (not assignable)
Rationale for reliability incl. deficiencies:
other: Only secondary literature available (review).
Principles of method if other than guideline:
Method: other: FHSA (Federal Hazardous Substances Act) test specified in C.F.R. 1500.41 et.seq.
GLP compliance:
no
Species:
rabbit
Type of coverage:
occlusive
Amount / concentration applied:
Concentration: 6 T49-004:wt%
Duration of treatment / exposure:
24 hour(s)
Irritation parameter:
primary dermal irritation index (PDII)
Score:
8

RS-Freetext:
AVERAGE SCORE: not reported
REVERSIBILITY: not reported
OTHER EFFECTS: not reported

Interpretation of results:
corrosive
Endpoint:
skin irritation / corrosion
Type of information:
experimental study
Adequacy of study:
other information
Reliability:
4 (not assignable)
Rationale for reliability incl. deficiencies:
other: Only secondary literature available (review).
Principles of method if other than guideline:
Method: other: DOT test, FHMTA 49 C.F.R. 173.240
GLP compliance:
no
Species:
rabbit
Type of coverage:
occlusive
Amount / concentration applied:
Concentration: 99 T49-004:wt%
Duration of treatment / exposure:
4 hour(s)

RS-Freetext:
AVERAGE SCORE: not reported
REVERSIBILITY: not reported
OTHER EFFECTS: not reported

Interpretation of results:
not irritating
Endpoint:
skin irritation: in vivo
Type of information:
experimental study
Adequacy of study:
other information
Reliability:
3 (not reliable)
Rationale for reliability incl. deficiencies:
other: The method was not validated at the time the study was performed. The article is limited in detail.
Principles of method if other than guideline:
Method: other: Skin irritation test
GLP compliance:
no
Species:
guinea pig
Type of coverage:
semiocclusive
Vehicle:
water
Amount / concentration applied:
Concentration: 37 T49-004:wt%
Duration of treatment / exposure:
4 hour(s)
Number of animals:
6
Irritation parameter:
primary dermal irritation index (PDII)
Score:
0.3

RS-Freetext:
AVERAGE SCORE
- Erythema: Not reported. 
- Edema: Not reported.
REVERSIBILITY: Not reported.
OTHER EFFECTS: PII intact skin: 0.0. PII abraded skin: 0.6.
PII: 0.3. There was tissue destruction in 0/6 intact skin
sites, and 0/6 abraded skin sites. Irritancy: negligible.

Interpretation of results:
not irritating
Endpoint:
skin irritation: in vivo
Type of information:
experimental study
Adequacy of study:
other information
Reliability:
3 (not reliable)
Rationale for reliability incl. deficiencies:
other: The method was not validated at the time the study was performed. The article is limited in detail.
Principles of method if other than guideline:
Method: other: Skin irritation test
GLP compliance:
no
Species:
rabbit
Type of coverage:
semiocclusive
Vehicle:
water
Amount / concentration applied:
Concentration: 37 T49-004:wt%
Duration of treatment / exposure:
4 hour(s)
Number of animals:
5
Irritation parameter:
primary dermal irritation index (PDII)
Score:
7.4

RS-Freetext:
AVERAGE SCORE
- Erythema: Not reported. 
- Edema: Not reported.
REVERSIBILITY: Lesions remained for at least 96 hrs.
OTHER EFFECTS: PII intact skin: 6.8. PII abraded skin: 8.0.
PII: 7.4. There was tissue destruction in 5/5 intact skin
sites, and 5/5 abraded skin sites. Irritancy: corrosive.

Interpretation of results:
corrosive
Endpoint:
skin irritation: in vivo
Type of information:
experimental study
Adequacy of study:
other information
Reliability:
3 (not reliable)
Rationale for reliability incl. deficiencies:
other: The method was not validated at the time the study was performed. The article is limited in detail.
Principles of method if other than guideline:
Method: other: Skin irritation test
GLP compliance:
no
Species:
human
Type of coverage:
semiocclusive
Amount / concentration applied:
Concentration: 37 T49-004:wt%
Duration of treatment / exposure:
4
Number of animals:
8
Irritation parameter:
primary dermal irritation index (PDII)
Score:
3.6

RS-Freetext:
AVERAGE SCORE
- Erythema: Not reported. 
- Edema: Not reported.
REVERSIBILITY: Lesions disappeared after unknown time
period.
OTHER EFFECTS: PII intact skin: 3.0. PII abraded skin: 4.2.
PII: 3.6. There was tissue destruction in 0/8 intact skin
sites, and 1/8 abraded skin sites. Irritancy: severe. A
single subject developed a severe erythematous and vesicular
reaction on intact skin. The lesion was not permanent.

Conclusions:
Classification: irritating
Endpoint:
skin irritation: in vivo
Type of information:
experimental study
Adequacy of study:
other information
Reliability:
3 (not reliable)
Rationale for reliability incl. deficiencies:
other: The method was not validated at the time the study was performed. The article is limited in detail.
Principles of method if other than guideline:
Method: other: Skin irritation test
GLP compliance:
no
Species:
rabbit
Type of coverage:
semiocclusive
Vehicle:
water
Duration of treatment / exposure:
4 hour(s)
Number of animals:
6
Irritation parameter:
primary dermal irritation index (PDII)
Score:
8

RS-Freetext:
AVERAGE SCORE
- Erythema: Not reported. 
- Edema: Not reported.
REVERSIBILITY: Lesions remained for at least 96 hrs.
OTHER EFFECTS: PII intact skin: 8.0. PII abraded skin: 8.0.
PII: 8.0. There was tissue destruction in 6/6 intact skin
sites, and 6/6 abraded skin sites. Irritancy: corrosive.

Interpretation of results:
corrosive
Endpoint:
skin irritation: in vivo
Type of information:
experimental study
Adequacy of study:
other information
Reliability:
3 (not reliable)
Rationale for reliability incl. deficiencies:
other: The method was not validated at the time the study was performed. The article is limited in detail.
Principles of method if other than guideline:
Method: other: Skin irritation test
GLP compliance:
no
Species:
guinea pig
Type of coverage:
semiocclusive
Duration of treatment / exposure:
4 hour(s)
Number of animals:
6
Irritation parameter:
primary dermal irritation index (PDII)
Score:
2.4

RS-Freetext:
AVERAGE SCORE
- Erythema: Not reported. 
- Edema: Not reported.
REVERSIBILITY: Lesions remained less than 96 hrs.
OTHER EFFECTS: PII intact skin: 1.7. PII abraded skin: 3.2.
PII: 2.4. There was tissue destruction in 0/6 intact skin
sites, and 3/6 abraded skin sites. Irritancy: moderate.

Interpretation of results:
moderately irritating
Endpoint:
skin irritation: in vivo
Type of information:
experimental study
Adequacy of study:
weight of evidence
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Guideline study, but no information on purity of test substance.
Qualifier:
according to guideline
Guideline:
OECD Guideline 404 (Acute Dermal Irritation / Corrosion)
Deviations:
no
GLP compliance:
yes
Remarks:
Inveresk Research International
Species:
rabbit
Strain:
New Zealand White
Details on test animals or test system and environmental conditions:
TEST ANIMALS: 
- Sex: Male
- Source: Cheshire Rabbit Farms Ltd.
- Age: approx. 11 weeks
- Weight at study initiation: 2.3 - 3.0 kg 
Type of coverage:
semiocclusive
Preparation of test site:
shaved
Vehicle:
water
Controls:
no
Amount / concentration applied:
0.5 g
Duration of treatment / exposure:
4 hour(s)
Observation period:
5 days
Number of animals:
1
Irritation parameter:
primary dermal irritation index (PDII)
Time point:
other: 1, 24, 48, 72 hours and 5 days
Score:
8
Reversibility:
not reversible
Remarks on result:
other: Some evidence of necrosis was observed. When the test substance was applied as dry powder, no erythema or oedema was observed.

AVERAGE SCORE:
- Erythema: 4
- Edema: 4

No further details on "results" available.


Interpretation of results:
corrosive
Endpoint:
skin irritation: in vivo
Type of information:
experimental study
Adequacy of study:
weight of evidence
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Guideline study, but no information on purity of test substance.
Qualifier:
according to guideline
Guideline:
OECD Guideline 404 (Acute Dermal Irritation / Corrosion)
Deviations:
no
GLP compliance:
yes
Remarks:
Inveresk Research International
Species:
rabbit
Strain:
New Zealand White
Details on test animals or test system and environmental conditions:
TEST ANIMALS: 
- Sex: Female
- Source: Cheshire Rabbit Farms ltd.
- Age: approx. 11 weeks
- Weight at study initiation: 2.3 - 3.0 kg 
Type of coverage:
semiocclusive
Preparation of test site:
shaved
Vehicle:
water
Controls:
no
Amount / concentration applied:
0.5 g
Duration of treatment / exposure:
4 hour(s)
Observation period:
up to 5 days
Number of animals:
1
Irritation parameter:
primary dermal irritation index (PDII)
Time point:
other: 1, 24, 48, 72 hours and 5 days
Score:
8
Reversibility:
not reversible
Remarks on result:
other: Severe reactions with some evidence of necrosis occured. When the test substance was applied as dry powder, no  erythema and oedema was observed.

AVERAGE SCORE:
- Erythema: 4
- Edema: 4

No further details on "results" available.

Interpretation of results:
corrosive
Endpoint:
skin irritation: in vivo
Type of information:
experimental study
Adequacy of study:
weight of evidence
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Guideline study, but no information on purity of test substance.
Qualifier:
according to guideline
Guideline:
OECD Guideline 404 (Acute Dermal Irritation / Corrosion)
Deviations:
no
GLP compliance:
yes
Remarks:
Inveresk Research International
Species:
rabbit
Strain:
New Zealand White
Details on test animals or test system and environmental conditions:
TEST ANIMALS: 
- Sex: Male
- Source: Cheshire Rabbit Farms ltd.
- Age: approx. 11 weeks
- Weight at study initiation: 2.3 - 3.0 kg 
Type of coverage:
semiocclusive
Preparation of test site:
shaved
Vehicle:
water
Controls:
no
Amount / concentration applied:
0.5 g
Duration of treatment / exposure:
4 hour(s)
Observation period:
5 days
Number of animals:
1
Irritation parameter:
primary dermal irritation index (PDII)
Time point:
other: 1, 24, 48, 72 hours and 5 days
Score:
8
Reversibility:
not reversible
Remarks:
Effects persisted for up to 5 days after exposure
Remarks on result:
other: Some evidence of necrosis was observed. When the test substance was applied as dry powder, no erythema and oedema was observed.

AVERAGE SCORE:
- Erythema: 4
- Edema: 4

No further details on "results" available.

Interpretation of results:
corrosive
Endpoint:
skin irritation: in vivo
Type of information:
experimental study
Adequacy of study:
weight of evidence
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: Guideline study
Qualifier:
according to guideline
Guideline:
OECD Guideline 404 (Acute Dermal Irritation / Corrosion)
GLP compliance:
yes
Remarks:
no data
Species:
rabbit
Strain:
not specified
Type of coverage:
semiocclusive
Preparation of test site:
shaved
Vehicle:
water
Controls:
not specified
Amount / concentration applied:
Concentration: 10%; 0.5 mL
Duration of treatment / exposure:
4 hour(s)
Observation period:
Examination time points: 24, 48 and 72 hours
Number of animals:
3
Irritation parameter:
primary dermal irritation index (PDII)
Time point:
other: 24, 48 and 72 hours
Score:
1.22
Reversibility:
other: The severity of erythema was reduced from 2 to 1 by day 2, but persisted. The oedema observed in 1 animal had reversed by day 2.

AVERAGE SCORE:
- Erythema: 1.11
- Edema: 0.11

No further details on "results" available.

Interpretation of results:
slightly irritating
Endpoint:
skin irritation: in vivo
Type of information:
experimental study
Adequacy of study:
weight of evidence
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: Guideline study
Qualifier:
according to guideline
Guideline:
OECD Guideline 404 (Acute Dermal Irritation / Corrosion)
Deviations:
not specified
GLP compliance:
yes
Remarks:
no data
Species:
rabbit
Strain:
not specified
Type of coverage:
semiocclusive
Preparation of test site:
shaved
Vehicle:
water
Controls:
not specified
Amount / concentration applied:
Concentration: 50 %; 0.5 mL
Duration of treatment / exposure:
4 hour(s)
Observation period:
Examination time points: 24, 48 and 72 hours
Number of animals:
3
Irritation parameter:
primary dermal irritation index (PDII)
Time point:
other: 24, 48 and 72 hours
Score:
3.67
Reversibility:
no data
Remarks on result:
other: Reaction extended outside application site.

AVERAGE SCORE:
- Erythema: 2.33
- Edema: 1.33

No further details on "results" available.

Interpretation of results:
irritating
Endpoint:
skin irritation: in vivo
Type of information:
experimental study
Adequacy of study:
weight of evidence
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Guideline study, but no information on purity of test substance.
Qualifier:
according to guideline
Guideline:
OECD Guideline 404 (Acute Dermal Irritation / Corrosion)
Deviations:
yes
Remarks:
The powder was not moistened before application.
GLP compliance:
yes
Remarks:
Forsvarets Forskningsanstalt
Species:
rabbit
Strain:
other: white landrace
Details on test animals or test system and environmental conditions:
- Source: Dörröds Djur -och Foderservice, Veberöd
- Weight at study initiation: 2.7 kg (average)
Type of coverage:
semiocclusive
Preparation of test site:
shaved
Vehicle:
unchanged (no vehicle)
Controls:
not specified
Amount / concentration applied:
Concentration: 57.5 T49-004:wt%; 0.5 g
Duration of treatment / exposure:
4 hour(s)
Observation period:
14 days
Number of animals:
3
Irritation parameter:
primary dermal irritation index (PDII)
Time point:
other: 24, 48 and 72 hours
Score:
7.8
Reversibility:
not reversible
Other effects:
2 out of 3 exposed animals showed an acute skin necrosis. The third animal had a pigmented necrosis (2 cm2) on the exposed area. The necrosis andthe acute oedema outside the tissue lesion remained during the following examinations. The wound was not healed after 14 days.

AVERAGE SCORE:
- Erythema: 4
- Edema: 3.8

No further details on "results" available.

Interpretation of results:
corrosive
Endpoint:
skin irritation: in vivo
Type of information:
experimental study
Adequacy of study:
weight of evidence
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Guideline study, but no information on purity of test substance.
Qualifier:
according to guideline
Guideline:
OECD Guideline 404 (Acute Dermal Irritation / Corrosion)
Deviations:
yes
Remarks:
The powder was not moistened before application.
GLP compliance:
yes
Remarks:
Forsvarets|Forskningsanstalt
Species:
rabbit
Strain:
other: white landrace
Details on test animals or test system and environmental conditions:
TEST ANIMALS: 
- Source: Dörröds Djur -och Foderservice, Veberöd
- Weight at study initiation: 2.7 kg (average) 
Type of coverage:
semiocclusive
Preparation of test site:
shaved
Vehicle:
unchanged (no vehicle)
Controls:
not specified
Amount / concentration applied:
Concentration: 97 T49-004:wt%; 0.5 g
Duration of treatment / exposure:
4 hour(s)
Observation period:
up to 14 days
Number of animals:
3
Irritation parameter:
primary dermal irritation index (PDII)
Time point:
other: 24, 48 and 72 hours
Score:
5.1
Reversibility:
not reversible
Other effects:
At the first examination two of the three exposed animals showed necrosis. The wounds of these two animals (1 and 3 cm2) together with a well defined oedema remained at all examinations and were not healed after the observation period of 14 days. The third animal showed four small wounds after 48 and 72 hours. The animal had fast growing fur which made it difficult to get close contact between the test substance and the exposed skin area. The wounds were healed within 14 days (observation period).

AVERAGE SCORE:
- Erythema: 2.8
- Edema: 2.3

No further details on "results" available.

Interpretation of results:
corrosive
Endpoint:
skin irritation: in vivo
Type of information:
experimental study
Adequacy of study:
weight of evidence
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Guideline study, but no information on purity of test substance.
Qualifier:
according to guideline
Guideline:
OECD Guideline 404 (Acute Dermal Irritation / Corrosion)
GLP compliance:
yes
Remarks:
Hazleton France
Species:
rabbit
Strain:
New Zealand White
Details on test animals or test system and environmental conditions:
- Source: Bancel
- Age: adult
- Weight at study initiation: 2.4-2.6 kg
Type of coverage:
semiocclusive
Preparation of test site:
shaved
Vehicle:
unchanged (no vehicle)
Controls:
not specified
Amount / concentration applied:
undiluted
Duration of treatment / exposure:
4 hour(s)
Observation period:
72 h
Number of animals:
3
Irritation parameter:
primary dermal irritation index (PDII)
Time point:
other: 24, 48 and 72 hours
Score:
0.17
Reversibility:
fully reversible

AVERAGE SCORE:
- Erythema: 0.22
- Oedema: 0.11
REVERSIBILITY: Erythema and oedema observed within 1 hour after exposure in one of three animals disappeared 72 hours after exposure.
OTHER EFFECTS: Only one animal developed a well defined erythema and a barely perceptible oedema within 1 hour after
exposure; the other two animals did not reveal erythema or oedema at any time.

Interpretation of results:
not irritating
Endpoint:
skin irritation: in vivo
Type of information:
experimental study
Adequacy of study:
weight of evidence
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Guideline study, but no information on purity of test substance.
Qualifier:
according to guideline
Guideline:
OECD Guideline 404 (Acute Dermal Irritation / Corrosion)
Deviations:
not specified
GLP compliance:
yes
Remarks:
Hazleton France
Specific details on test material used for the study:
Details on the test material are given above.
Species:
rabbit
Strain:
other: New Zealand hybrid
Details on test animals or test system and environmental conditions:
TEST ANIMALS: 
- Sex: male
- Source: Bancel 
- Age: adult
- Weight at study initiation: 2.6 - 2.7 kg
Type of coverage:
semiocclusive
Preparation of test site:
shaved
Vehicle:
water
Controls:
not specified
Amount / concentration applied:
- Concentration in vehicle: 0.5 g/0.10 g purified water
- Total volume applied: 0.3 ml
Duration of treatment / exposure:
4 hour(s)
Observation period:
14 days
Number of animals:
3
Irritation parameter:
primary dermal irritation index (PDII)
Time point:
other: 24, 48 and 72 hours
Score:
4.67
Reversibility:
other: Erythema persisted for at least 14 days, while oedema, observed within 1 hour after exposure, disappeared 72 hours after exposure.
Remarks on result:
other: Necrosis persisted in the entire area of application for 7 days and in parts of the test area for at least 14 days.

AVERAGE SCORE:
- Erythema: 4
- Edema: 0.67

No further details on "results" available.

 

Interpretation of results:
corrosive
Endpoint:
skin corrosion: in vitro / ex vivo
Type of information:
experimental study
Adequacy of study:
weight of evidence
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Comparable to guideline study.
Qualifier:
equivalent or similar to guideline
Guideline:
EU Method B.40 (In Vitro Skin Corrosion: Transcutaneous Electrical Resistance Test (TER))
Deviations:
yes
Remarks:
see "Any other information on materials and methods"
GLP compliance:
no
Species:
rat
Strain:
Wistar
Details on test animals or test system and environmental conditions:
TEST ANIMALS:
- Sex: male
- Age: 28 days
- Weight at study initiation: 60-80 grams
Type of coverage:
open
Preparation of test site:
abraded
Vehicle:
unchanged (no vehicle)
Controls:
not specified
Amount / concentration applied:
0.3 mL
Duration of treatment / exposure:
1 hour
Observation period:
1 h
Irritation / corrosion parameter:
other: other: electrical resistance value (kOhm. disc)
Value:
0.4
Remarks on result:
other:
Remarks:
Time point: 1 h. (migrated information)
Interpretation of results:
corrosive

Eye irritation

Link to relevant study records

Referenceopen allclose all

Endpoint:
eye irritation, other
Type of information:
experimental study
Adequacy of study:
other information
Reliability:
4 (not assignable)
Rationale for reliability incl. deficiencies:
other: Only secondary literature available (review).
Principles of method if other than guideline:
Method: other: FHSA (Federal Hazardous Substances Act) specified in C.F.R. 1500.42 et.seq.
GLP compliance:
no
Species:
rabbit
Amount / concentration applied:
Concentration: 10 other: wt%

RS-Freetext:
AVERAGE SCORE: Not reported
REVERSIBILITY: Not reported
OTHER EFFECTS: Not reported

Interpretation of results:
irritating
Endpoint:
eye irritation, other
Type of information:
experimental study
Adequacy of study:
other information
Reliability:
4 (not assignable)
Rationale for reliability incl. deficiencies:
other: Only secondary literature available (review).
Principles of method if other than guideline:
Method: other: FHSA (Federal Hazardous Substances Act) specified in C.F.R. 1500.42 et.seq.
GLP compliance:
no
Species:
rabbit
Amount / concentration applied:
Concentration: 6 other: wt%

RS-Freetext:
AVERAGE SCORE: not reported
DESCRIPTION OF LESIONS: not reported
REVERSIBILITY: not reported
OTHER EFFECTS: not reported

Interpretation of results:
irritating
Endpoint:
eye irritation, other
Type of information:
experimental study
Adequacy of study:
other information
Reliability:
4 (not assignable)
Rationale for reliability incl. deficiencies:
other: Only secondary literature available (review).
Principles of method if other than guideline:
Method: other: FHSA (Federal Hazardous Substances Act) specified in C.F.R. 1500.42 et.seq.
GLP compliance:
no
Species:
rabbit
Amount / concentration applied:
Concentration: 5 other: wt%

RS-Freetext:
AVERAGE SCORE: not reported
DESCRIPTION OF LESIONS: not reported
REVERSIBILITY: not reported
OTHER EFFECTS: not reported

Interpretation of results:
irritating
Endpoint:
eye irritation, other
Type of information:
experimental study
Adequacy of study:
other information
Reliability:
4 (not assignable)
Rationale for reliability incl. deficiencies:
other: Only secondary literature available (review).
Principles of method if other than guideline:
Method: other: FHSA (Federal Hazardous Substances Act) specified in C.F.R. 1500.42 et.seq.
GLP compliance:
no
Species:
rabbit
Amount / concentration applied:
Concentration: 3 other: wt%

RS-Freetext:
AVERAGE SCORE: not reported
DESCRIPTION OF LESIONS: not reported
REVERSIBILITY: not reported
OTHER EFFECTS: not reported

Interpretation of results:
irritating
Endpoint:
eye irritation, other
Type of information:
experimental study
Adequacy of study:
other information
Reliability:
3 (not reliable)
Rationale for reliability incl. deficiencies:
other: Method not validated and only secondary literature available.
Principles of method if other than guideline:
Method: other: Esophageal test
GLP compliance:
no
Species:
rabbit

RS-Freetext:
MORTALITY: Not reported
CLINICAL SIGNS: Not reported
NECROPSY FINDINGS: Corrosive effects in the esophagus
POTENTIAL TARGET ORGANS: Not reported
SEX-SPECIFIC DIFFERENCES: Not reported

R

M-Freetext:
Schleyer et al. (1982) reports on a series of esophageal
tests (oral, rabbit) conducted under the auspicies of the
Consumer Product Safety Commission. 
Microscopic examination of the esophagus was used as the
primary criterion for categorizing results as either
"corrosive" or "negative". The data is given below.
SiO2/Na2O       Concentration     Results
weight ratio
1.0             10% w/v           +,+

Endpoint:
eye irritation: in vivo
Data waiving:
other justification
Justification for data waiving:
the study need not be conducted because the available information indicates that the criteria are met for classification as corrosive to the skin or irritating to eyes
the study need not be conducted because the substance is a strong acid (pH <= 2.0) or base (pH => 11.5)
other:
Endpoint:
eye irritation: in vitro / ex vivo
Data waiving:
study scientifically not necessary / other information available
Justification for data waiving:
the study need not be conducted because the available information indicates that the criteria are met for classification as corrosive to the skin or irritating to eyes
the study need not be conducted because the substance is a strong acid (pH <= 2.0) or base (pH => 11.5)
Endpoint:
eye irritation: in vitro / ex vivo
Type of information:
experimental study
Adequacy of study:
other information
Reliability:
4 (not assignable)
Rationale for reliability incl. deficiencies:
other: see 'Remark'
Remarks:
The method is well-documented, but not validated. There are no guidelines for this kind of study, but the protocol is in use as an alternative to in vivo eye irritation studies for substances which are shown to be skin irritating/corrosive in in vivo studies.
Principles of method if other than guideline:
In vitro rabbit eye irritation study according to York et al., 1994; York et  al., 1982; Burton et al., 1981.
GLP compliance:
yes
Remarks:
Environmental safety laboratory, Unilever Research, Bedford UK.
Species:
rabbit
Strain:
New Zealand White
Details on test animals or tissues and environmental conditions:
TEST ANIMALS: 
- Source: Huntingdon Research centre (HRC) ltd.
Vehicle:
unchanged (no vehicle)
Controls:
not required
Amount / concentration applied:
undiluted ; 50 mg
Duration of treatment / exposure:
0.17 minute(s)
Irritation parameter:
other: opacity score
Basis:
mean
Time point:
other: 30 minutes, 1, 2, 3 and 4 hours after treatment
Score:
> 0

AVERAGE SCORE:
- Maximum macroscopic and microscopic opacity score: 4 (complete corneal opacity, iris not discernible)
- Mean maximum corneal swelling: 41.30% (increase in thickness)
- Fluorescein staining: extreme (intense staining  of very badly damaged cornea, appears yellow/orange as opposed to
the bright green in previous grades).
- Loss of corneal cell layers: 3-6 (a normal cornea has ca. 8 layers)


REVERSIBILITY: Not applicable


OTHER EFFECTS: The overall result was severe irritation (moderate/severe opacity and/or >35% swelling and/or 7-8
cell layers of the cornea lost)

Interpretation of results:
corrosive
Endpoint:
eye irritation: in vitro / ex vivo
Type of information:
experimental study
Adequacy of study:
other information
Reliability:
4 (not assignable)
Rationale for reliability incl. deficiencies:
other: see 'Remark'
Remarks:
The method is well-documented, but not validated. There are no guidelines for this kind of study, but the protocol is in use as an alternative to in vivo eye irritation studies for substances which are shown to be skin irritating/corrosive in in vivo studies.
Principles of method if other than guideline:
In vitro rabbit eye irritation study discribed by York et  al., 1982; Burton et al., 1981.
The method is not validated yet, but is in use as an alternative to in vivo eye irritation studies, providing the test substance is shown to be skin irritating/corrosive.
GLP compliance:
yes
Remarks:
no data
Species:
rabbit
Strain:
New Zealand White
Vehicle:
unchanged (no vehicle)
Controls:
not specified
Amount / concentration applied:
undiluted ; 50 mg
Duration of treatment / exposure:
0.17 minute(s)
Irritation parameter:
other: opacity score
Basis:
mean
Time point:
other: 30 minutes, 1, 2, 3 and 4 hours after treamtent
Score:
> 0
Max. score:
4

AVERAGE SCORE:
- Maximum macroscopic and microscopic opacity score: 4 (complete corneal opacity, iris not discernible)
- Mean maximum corneal swelling: 43.18% (increase in thickness)
- Fluorescein staining: extreme (intense staining  of very badly damaged cornea, appears yellow/orange as opposed to the bright

green in previous grades).
- Loss of corneal cell layers: 2-4 (a normal cornea has ca. 8 layers)


REVERSIBILITY: Not applicable


OTHER EFFECTS: The overall result was severe irritation (moderate/severe opacity and/or >35% swelling and/or 7-8 cell

layers of the cornea

Interpretation of results:
corrosive

Additional information

Disodium metasilicate is irritating as a 10% and corrosive as a 50% aqueous solution. When tested as an anhydrous powder, it was not irritating to the skin, when moistened with water it was found to be corrosive. Taking into account the results of the studies, the degree of irritation is dependent on the concentration (and therefore water content): lower concentrations exhibit lower irritancy compared to higher concentrations of the same molar ratio.

Due to animal welfare, in vivo studies were not conducted since the substance is skin irritating/corrosive and at the same time a strong base (pH > 11.5). Results from non-validated in vitro assays (in vitro rabbit eye test) indicate corrosiveness of disodium metasilicate, either administered as a powder or as granules with a molar ratio of 1.0.

Justification for classification or non-classification

DSD:Causes burns. Irritating to the respiratory system. According to Annex I the substance is classified as C; R34 and Xi; R37.

CLP:Causes severe skin burns and eye damage. May cause respiratory irritation. According to Annex VI disodium metasilicate is classified as Skin corr 1B, H314 and STOT SE 3, H335.