Registration Dossier

Administrative data

Description of key information

Sodium silicate can be irritating to corrosive to the skin of rabbits, depending on the molar ratio and concentration.

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:
supporting study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Study according to OECD Guideline, but only 1 animal tested.
Qualifier:
according to
Guideline:
OECD Guideline 404 (Acute Dermal Irritation / Corrosion)
Deviations:
yes
Remarks:
only one animal tested
GLP compliance:
yes
Remarks:
Inveresk Research International
Species:
rabbit
Strain:
New Zealand White
Details on test animals 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:
unchanged (no vehicle)
Controls:
not specified
Amount / concentration applied:
Concentration: 40.9 other: wt%; 0.5 mL
Duration of treatment / exposure:
The exposure lasted 1 min, 1 hr or 4 hrs.
Observation period:
up to 5 days
Number of animals:
1
Details on study design:
- Removal of test substance: yes (washed away with water)
- Scoring system: according to Draize 
- Examination time points: 1, 24, 48, 72 hours and 5 days
Irritation parameter:
primary dermal irritation index (PDII)
Score:
3
Reversibility:
other: Effects persisted for at least 5 days.

AVERAGE SCORE: 
- Erythema: 2
- Edema: 1

Interpretation of results:
irritating
Endpoint:
skin irritation: in vivo
Type of information:
experimental study
Adequacy of study:
supporting study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Study according to OECD Guideline, but only 1 animal tested.
Qualifier:
according to
Guideline:
OECD Guideline 404 (Acute Dermal Irritation / Corrosion)
Deviations:
yes
Remarks:
only one animal tested
GLP compliance:
yes
Remarks:
Inveresk Research International
Species:
rabbit
Strain:
New Zealand White
Details on test animals 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:
unchanged (no vehicle)
Controls:
not specified
Amount / concentration applied:
Concentration: 39.9 other: wt%; 0.5 mL
Duration of treatment / exposure:
The exposure lasted 1 min, 1 hr or 4 hrs
Observation period:
up to 5 days
Number of animals:
1
Details on study design:
- Removal of test substance: yes (washed away with water)
- Scoring system: according to Draize 
- Examination time points: 1, 24, 48, 72 hours and 5 days
Irritation parameter:
primary dermal irritation index (PDII)
Score:
3
Reversibility:
not reversible

AVERAGE SCORE: 
- Erythema: 2
- Edema: 1

No further details on "results" available.


Interpretation of results:
irritating
Endpoint:
skin irritation: in vivo
Type of information:
experimental study
Adequacy of study:
supporting study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Study according to OECD Guideline, but only 1 animal tested.
Qualifier:
according to
Guideline:
OECD Guideline 404 (Acute Dermal Irritation / Corrosion)
Deviations:
yes
Remarks:
only one animal tested
GLP compliance:
yes
Remarks:
Inveresk Research International
Species:
rabbit
Strain:
New Zealand White
Details on test animals 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:
unchanged (no vehicle)
Controls:
not specified
Amount / concentration applied:
Concentration: 39 other: wt%; 0.5 mL
Duration of treatment / exposure:
The exposure lasted 1 min, 1 hr or 4 hrs.
Observation period:
Examination time points: 1, 24, 48, 72 hours and 5 days.
Number of animals:
1
Details on study design:
- Removal of test substance: yes (washed away with water)
- Scoring system: according to Draize  
Irritation parameter:
primary dermal irritation index (PDII)
Score:
0

AVERAGE SCORE: 
- Erythema: 0
- Edema: 0

No further details on "results" available.


Interpretation of results:
not irritating
Endpoint:
skin irritation: in vivo
Type of information:
experimental study
Adequacy of study:
supporting study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Study according to OECD Guideline, but only 1 animal tested.
Qualifier:
according to
Guideline:
OECD Guideline 404 (Acute Dermal Irritation / Corrosion)
Deviations:
yes
Remarks:
only one animal tested
GLP compliance:
yes
Remarks:
Inveresk Research International
Species:
rabbit
Strain:
New Zealand White
Type of coverage:
semiocclusive
Preparation of test site:
shaved
Vehicle:
unchanged (no vehicle)
Controls:
not specified
Amount / concentration applied:
Concentration: 38.3 other: wt%
Duration of treatment / exposure:
uo to 4 hour(s)
Observation period:
5 days
Number of animals:
1
Irritation parameter:
primary dermal irritation index (PDII)
Score:
0.33

AVERAGE SCORE: 
- Erythema: 0.33
- Edema: 0
REVERSIBILITY: At 48 hrs erythema was no longer observed.

Interpretation of results:
not irritating
Endpoint:
skin irritation: in vivo
Type of information:
experimental study
Adequacy of study:
key study
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:
OECD Guideline 404 (Acute Dermal Irritation / Corrosion)
GLP compliance:
yes
Remarks:
Forsvarets Forskningsanstalt
Species:
rabbit
Strain:
other: White Landrace
Details on test animals 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:
no
Amount / concentration applied:
0.5 g/mL applied
Concentration: 53.5 wt% in water
Duration of treatment / exposure:
4 hour(s)
Observation period:
One week for animals with no lesions and 14 days for animals with wounds.
Number of animals:
3
Details on study design:
- Removal of test substance with water after 4 hrs exposure
- Scoring system: skin irritation index, according to OECD 404. 
- Examination time points: 1, 24, 48 and 72 hours
Irritation parameter:
primary dermal irritation index (PDII)
Time point:
other: 24, 48, 72 h
Score:
8
Reversibility:
not reversible
Irritation parameter:
erythema score
Basis:
animal #1
Time point:
24/48/72 h
Score:
4
Max. score:
4
Reversibility:
not reversible
Remarks:
observation for 14 d
Remarks on result:
probability of severe irritation
Irritation parameter:
erythema score
Basis:
animal #2
Time point:
24/48/72 h
Score:
4
Max. score:
4
Reversibility:
not reversible
Remarks:
observation for 14 d
Remarks on result:
probability of severe irritation
Irritation parameter:
erythema score
Basis:
animal #3
Time point:
24/48/72 h
Score:
4
Max. score:
4
Reversibility:
not reversible
Remarks:
observation for 14 d
Remarks on result:
probability of severe irritation
Irritation parameter:
edema score
Basis:
animal #1
Time point:
24/48/72 h
Score:
4
Max. score:
4
Reversibility:
not reversible
Remarks:
observation for 14 d
Remarks on result:
probability of severe irritation
Irritation parameter:
edema score
Basis:
animal #2
Time point:
24/48/72 h
Score:
4
Max. score:
4
Reversibility:
not reversible
Remarks:
observation for 14 d
Remarks on result:
probability of severe irritation
Irritation parameter:
edema score
Basis:
animal #3
Time point:
24/48/72 h
Score:
4
Max. score:
4
Reversibility:
not reversible
Remarks:
observation for 14 d
Remarks on result:
probability of severe irritation
Other effects:
All exposed animals showed an acute necrosis. The necrosis and an acute oedema outside the wound remained during the following examinations.

AVERAGE SCORE: 
- Erythema: 4
- Edema: 4

No further details on "results" available.


Interpretation of results:
Category 1 (corrosive) based on GHS criteria
Endpoint:
skin irritation: in vivo
Type of information:
experimental study
Adequacy of study:
key study
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:
OECD Guideline 404 (Acute Dermal Irritation / Corrosion)
GLP compliance:
yes
Remarks:
Forsvarets Forskningsanstalt
Species:
rabbit
Strain:
other: white landrace
Details on test animals 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:
no
Amount / concentration applied:
0.5 g/mL applied
Concentration: 82% in water
Duration of treatment / exposure:
4 hour(s)
Observation period:
One week for animals with no lesions and 14 days for animals with wounds.
Number of animals:
3
Details on study design:
- Removal of test substance with water after 4 hrs exposure
- Scoring system: skin irritation index, according to OECD 404. 
- Examination time points: 1, 24, 48 and 72 hrs
Irritation parameter:
primary dermal irritation index (PDII)
Time point:
other: 24, 48, 72 h
Score:
4.6
Reversibility:
not fully reversible within: 1 animal had a wound that had not healed after 14 days. The skin on the other animal had healed after 14 days.
Irritation parameter:
erythema score
Basis:
animal #1
Time point:
24/48/72 h
Score:
4
Max. score:
4
Reversibility:
not reversible
Remarks:
observation for 14 d
Remarks on result:
probability of severe irritation
Irritation parameter:
erythema score
Basis:
animal #2
Time point:
24/48/72 h
Score:
0
Max. score:
0
Remarks on result:
no indication of irritation
Irritation parameter:
erythema score
Basis:
animal #3
Time point:
24/48/72 h
Score:
4
Max. score:
4
Reversibility:
fully reversible within:
Remarks:
14 d
Remarks on result:
probability of severe irritation
Irritation parameter:
edema score
Basis:
animal #1
Time point:
24/48/72 h
Score:
1.3
Max. score:
2
Reversibility:
not reversible
Remarks:
observation for 14 d
Remarks on result:
probability of severe irritation
Irritation parameter:
edema score
Basis:
animal #2
Time point:
24/48/72 h
Score:
0
Max. score:
0
Remarks on result:
no indication of irritation
Irritation parameter:
edema score
Basis:
animal #3
Time point:
24/48/72 h
Score:
4
Max. score:
4
Reversibility:
fully reversible within: 14 d
Remarks on result:
probability of severe irritation
Other effects:
2 of 3 animals showed necrotic skin lesions. 1 animal had a local necrosis which remained together with an acute oedema during the whole examination period. The second animal had a pigmented wound with an acute oedema which decreased to a slight oedema after 72 hrs. The third animal showed no skin irritancy. The fur grew fast on this animal, which made it difficult to obtain close contact between the test substance and the exposed area.

AVERAGE SCORE: 
- Erythema: 2.6
- Edema: 2.0

No further details on "results" available.

Interpretation of results:
other: probability of severe irritation
Endpoint:
skin irritation: in vivo
Type of information:
experimental study
Adequacy of study:
key study
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:
OECD Guideline 404 (Acute Dermal Irritation / Corrosion)
GLP compliance:
yes
Remarks:
Forsvarets Forskningsanstalt
Species:
rabbit
Strain:
other: White landrace
Details on test animals 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:
no
Amount / concentration applied:
0.5 g/mL applied
Concentration: 34.5 wt% in water
Duration of treatment / exposure:
4 hour(s)
Observation period:
One week for animals with no lesions and 14 days for animals with wounds.
Number of animals:
3
Details on study design:
Test substance was removed with water after 4 hrs exposure.
- Scoring system: skin irritation index, according to OECD 404. 
- Examination time points: 1, 24, 48 and 72 hours
Irritation parameter:
primary dermal irritation index (PDII)
Time point:
other: 24, 48, 72 h
Score:
0.4
Reversibility:
other: 1 of 3 rabbits had redness that persisted until 72 hrs and oedema observed only 48 hrs after exposure ended
Irritation parameter:
erythema score
Basis:
animal #1
Time point:
24/48/72 h
Score:
0
Max. score:
0
Remarks on result:
no indication of irritation
Irritation parameter:
erythema score
Basis:
animal #2
Time point:
24/48/72 h
Score:
1
Max. score:
1
Reversibility:
fully reversible
Irritation parameter:
erythema score
Basis:
animal #3
Time point:
24/48/72 h
Score:
0
Max. score:
0
Remarks on result:
no indication of irritation
Irritation parameter:
edema score
Basis:
animal #1
Time point:
24/48/72 h
Score:
0
Max. score:
0
Remarks on result:
no indication of irritation
Irritation parameter:
edema score
Basis:
animal #2
Time point:
24/48/72 h
Score:
0.3
Max. score:
1
Reversibility:
fully reversible
Irritation parameter:
edema score
Basis:
animal #3
Time point:
24/48/72 h
Score:
0
Max. score:
0
Remarks on result:
no indication of irritation

AVERAGE SCORE: 
- Erythema: 0.3
- Edema: 0.1

No further details on "results" available.


Interpretation of results:
GHS criteria not met
Endpoint:
skin irritation: in vivo
Type of information:
experimental study
Adequacy of study:
other information
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Guideline study, adapted to human conditions. No information on purity of test substance.
Qualifier:
according to
Guideline:
OECD Guideline 404 (Acute Dermal Irritation / Corrosion)
Deviations:
yes
Remarks:
study design adjusted to humans
GLP compliance:
yes
Remarks:
Henkel KGaA Dermatologie
Species:
human
Type of coverage:
semiocclusive
Vehicle:
water
Amount / concentration applied:
Concentration: 34.9 other: wt%
Duration of treatment / exposure:
4 hour(s)
Observation period:
up to 72 h
Number of animals:
20 (10 male and 10 female volunteers)
Details on study design:
500 µL of undiluted sodium silicate or a 50% aqueous solution of the substance was applied to the inside of the lower arm and covered by a semi-occlusive patch, app. 1.5 cm2. 2 hrs after application, the site was examined for irritation, and removed if strong irritation was observed. The patch was removed after 4 hrs, and the test site rinsed.

The occurrence of erythema, oedema, flaking/dandruff and fissures in the skin was assessed according to Frosch' scoring  system (PJ Frosch, AM Kligman: J Am Acad Dermatol 1, 1979, 35-41.). The scores were summed and an irritation score derived from the results. Sodium dodecylsulfate 20% was used a positive control, if the results did not differ significantly (p greater than or equal to 0.05) from those of the positive control, it was considered irritating.

Clinical signs:

The undiluted test substance caused slight scaling of the skin in 7/20 volunteers and strong scaling in 1/20. The total score was 0.45. Exposure to a 50% dilution caused slight scaling of the skin in 7/20 volunteers and
strong scaling in 1/20, giving the total score 0.45.

Undiluted sodium silicate 37/40 caused scaling of the skin in 8/20 volunteers, but is not considered irritating to the skin. A 50% dilution of sodium silicate 37/40 resulted in scaling of the skin in 9/20 subjects,
giving a total score of 0.50.

The positive control caused erythema within 2 hrs, with a score of 21.8. The negative control, water, did not cause any
adverse effects.

 

Interpretation of results:
not irritating
Endpoint:
skin irritation / corrosion, other
Remarks:
human volunteer study
Type of information:
experimental study
Adequacy of study:
other information
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Guideline study, adapted to human conditions. No information on purity of test substance.
Principles of method if other than guideline:
COLIPA open cutaneous test
GLP compliance:
yes
Remarks:
Henkel KGaA Dermatologie
Species:
human
Type of coverage:
open
Vehicle:
water
Amount / concentration applied:
Concentration: 34.9 other: wt%
application of 5, 10, 50% aqueous solutions and undiluted
Duration of treatment / exposure:
30 minute(s), the test substance was reapplied with a glass stick every 30 seconds. The test area on the inner lower arm was 3 cm2. After 30 minutes, the test area was rinsed with water and dried.
Number of animals:
20 volunteers (10 male and 10 female)
Details on study design:
The adverse skin effects were scored for erythema and oedema until 30 minutes after the last application. The range ran from 0 (no reaction) to 4 (very strong redness spreading outside the test site and/or very strong oedema >2 mm). In addition the subjects were questioned to assess the occurrence of burning sensation, itching, pain, heat, cold.

Clinical signs:

Exposure to undiluted sodium silicate solution did not cause any irritation. It rapidly hardened on the skin, forming a wax-like coating. The 50% aqueous dilution caused slight redness (barely perceptible erythema) in 3/20
volunteers 21-25 minutes after the exposure started, and lasted 15-19 minutes. The 10% aqueous dilution caused slight
redness (barely perceptible erythema) in 2/20 volunteers 21and 25 minutes after the exposure started, and lasted 19 and
15 minutes, respectively. Exposure to 5% dilution resulted in slight redness (barely perceptible erythema) in
2/20 volunteers, which started 25 and 21 minutes after the first exposure and lasted 15 and 19 minutes in total,
respectively. A third volunteer had a slight itch that started right after the exposure ended, and lasted 30
minutes. All the adverse effects were reversible.


Under non-occlusive conditions the 5, 10 and 50% aqueous dilutions of the sodium silicate solution caused slight irritation
(barely perceptible erythema). The undiluted sodium silicate solution did not cause irritation.

Interpretation of results:
not irritating
Endpoint:
skin irritation: in vivo
Type of information:
experimental study
Adequacy of study:
other information
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Comparable to guideline study.
Principles of method if other than guideline:
comparable to Directive 2000/33/EC, B.40
GLP compliance:
no
Species:
rat
Strain:
Wistar
Details on test animals 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:
shaved
Vehicle:
water
Controls:
not required
Amount / concentration applied:
Concentration: 52 other: wt%; 0.3 mL
Duration of treatment / exposure:
4 hour(s)

AVERAGE SCORE:
- Erythema: not applicable
- Oedema: not applicable

ELECTRICAL RESISTANCE VALUE (kOhm.disc): kOhm.disc (1hr): 1.1 (SD 0.3), kOhm.disc (4hrs): 0.9 (SD 0.1)


ANY OTHER INFORMATION: The substance is predicted to be corrosive.

Interpretation of results:
corrosive
Endpoint:
skin irritation: in vivo
Type of information:
experimental study
Adequacy of study:
other information
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Comparable to guideline study.
Principles of method if other than guideline:
comparable to Directive 2000/33/EC, B.40
GLP compliance:
no
Species:
rat
Strain:
Wistar
Details on test animals 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:
shaved
Vehicle:
water
Controls:
not required
Amount / concentration applied:
Concentration: 44 other: wt%; 0.3 mL
Duration of treatment / exposure:
24 hour(s)

ELECTRICAL RESISTANCE VALUE (kOhm.disc): 
kOhm.disc (1 hr)  : 4.6 (SD 1.3) 
kOhm.disc (4hrs)  : 3.5 (SD 1.5)
kOhm.disc (24 hrs): 1.1 (SD 0.6)


ANY OTHER INFORMATION: 4 hr exposure: resistance measured at 24 hrs: 7.6 (SD 1.4)


The substance is predicted to be corrosive.

Interpretation of results:
corrosive
Endpoint:
skin irritation: in vivo
Type of information:
experimental study
Adequacy of study:
other information
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Comparable to guideline study.
Principles of method if other than guideline:
comparable to Directive 2000/33/EC, B.40
GLP compliance:
no
Species:
rat
Strain:
Wistar
Details on test animals 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:
shaved
Vehicle:
water
Controls:
not required
Amount / concentration applied:
Concentration: 38 other: wt%; 0.3 mL
Duration of treatment / exposure:
24 hour(s)
Number of animals:
- Number of skin discs: 3

ELECTRICAL RESISTANCE VALUE (kOhm.disc): 
kOhm.disc (1 hr)  : 7.3 (SD 2.5) 
kOhm.disc (4 hrs) : 2.8 (SD 0.3) 
kOhm.disc (24 hrs): 1.6 (SD 0.1)


ANY OTHER INFORMATION: 4 hr exposure: resistance measured at 24 hrs: 7.5 (SD 0.2)


The substance is predicted to be corrosive.

Interpretation of results:
corrosive

Eye irritation

Link to relevant study records

Referenceopen allclose all

Endpoint:
eye irritation: in vitro / ex vivo
Type of information:
experimental study
Adequacy of study:
weight of evidence
Study period:
16 Mar - 18 Mar 1993
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
study well documented, meets generally accepted scientific principles, acceptable for assessment
Remarks:
The method is well-documented, but not yet validated. It is currently in use as an alternative to in vivo eye irritation studies for substances which are shown to be irritating in skin irritation tests.
Principles of method if other than guideline:
ex vivo rabbit eye irritation study
GLP compliance:
yes
Remarks:
Environmental Safety Laboratory, Unilever Research, Bedford UK.
Species:
rabbit
Vehicle:
unchanged (no vehicle)
Controls:
other: 2 untreated eyes served as control
Amount / concentration applied:
undiluted
Amount applied: 50 mg
Duration of treatment / exposure:
1 minute(s)
Observation period (in vivo):
eyes ex vivo were checked 0.5, 1, 2, 3, and 4 h after treatment for opacification of the cornea and corneal thickness
1 h after treatment fluorescein solution was applied and the rate of fluorescein diffusion into the corneal stroma was assessed togehter with possible corneal damage
4 h after treatment eyes were dissected and corneas underwent histological examination
Number of animals or in vitro replicates:
3 rabbit eyes (ex vivo) were treated with the test substance
2 control rabbit eyes (ex vivo) were untreated
Irritation parameter:
cornea opacity score
Run / experiment:
1 min treatment
Value:
4
Vehicle controls validity:
not applicable
Negative controls validity:
not applicable
Positive controls validity:
not applicable
Remarks on result:
other: 4 = Complete corneal opacity, iris not discernible.
Irritation parameter:
percent corneal swelling
Run / experiment:
1 min treatment
Value:
> 0 - < 100
Vehicle controls validity:
not applicable
Negative controls validity:
not applicable
Positive controls validity:
not applicable
Remarks on result:
other: No corneal swelling measurements were taken because of the considerable damage to the corneal surface.
Irritation parameter:
other: fluorescein staining
Run / experiment:
1 min treatment
Value:
4
Vehicle controls validity:
not applicable
Negative controls validity:
not applicable
Positive controls validity:
not applicable
Remarks on result:
other: 4 = Strong - Intense staining of the epithelium and anterior stroma with very rapid diffusion into the remainder of the stroma.
Irritation parameter:
histopathological observations
Run / experiment:
1 min treatment
Value:
>= 1 - <= 7
Vehicle controls validity:
not applicable
Negative controls validity:
not applicable
Positive controls validity:
not applicable
Remarks on result:
other: Loss of corneal cell layers: 1-7 (According to the study report, 8 epithelial cell layers are normal.)

AVERAGE SCORE: 
- Maximum opacity score:
10 seconds: 1-2 ((1): scattered/diffuse areas of opacity or loss of corneal epithelium, iris clearly visible/ (2): easily discernable greyish transculant areas, details of iris slightly obscured)
60 seconds: 4 (complete corneal opacity, iris not discernable)


- Maximum mean swelling: 
10 seconds: 23.26%
60 seconds: Not measurable


- Fluorescein staining: 
10 seconds: distinct (pale continous staining of the epithelium with slow diffusion into stroma)
60 seconds: strong (intense staining of the epithelium and anterior stroma with very rapid diffusion into the remainder
of the stroma)


- Loss of corneal cell layers:
10 seconds: 3-7 
60 seconds: 1-7

Interpretation of results:
Category 1 (irreversible effects on the eye) based on GHS criteria
Endpoint:
eye irritation: in vitro / ex vivo
Type of information:
experimental study
Adequacy of study:
weight of evidence
Study period:
16 Mar - 18 Mar 1993
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
study well documented, meets generally accepted scientific principles, acceptable for assessment
Remarks:
The method is well-documented, but not yet validated. It is currently in use as an alternative to in vivo eye irritation studies for substances which are shown to be irritating in skin irritation tests.
Principles of method if other than guideline:
ex vivo rabbit eye irritation study
GLP compliance:
yes
Remarks:
Environmental Safety Laboratory, Unilever Research, Bedford UK.
Species:
rabbit
Details on test animals or tissues and environmental conditions:
TEST ANIMALS: 
- Source: Laboratories of Industrial Toxicology, Huntingdon Research Centre Ltd. (HRC)
The eyes were from animals used by HRC in skin irritation tests or were the control eyes from eye irritation tests.
Vehicle:
unchanged (no vehicle)
Controls:
other: 2 untreated eyes served as control
Amount / concentration applied:
undiluted
Amount applied: 50 mg
Duration of treatment / exposure:
1 minute(s)
Observation period (in vivo):
eyes ex vivo were checked 0.5, 1, 2, 3, and 4 h after treatment for opacification of the cornea and corneal thickness
1 h after treatment fluorescein solution was applied and the rate of fluorescein diffusion into the corneal stroma was assessed togehter with possible corneal damage
4 h after treatment eyes were dissected and corneas underwent histological examination
Number of animals or in vitro replicates:
3 rabbit eyes (ex vivo) were treated with the test substance
2 control rabbit eyes (ex vivo) were untreated
Irritation parameter:
cornea opacity score
Run / experiment:
1 min treatment
Value:
2
Vehicle controls validity:
not applicable
Negative controls validity:
not applicable
Positive controls validity:
not applicable
Remarks on result:
other: 2 = early discernable greyish transculant areas, details of iris slightly obscured
Irritation parameter:
percent corneal swelling
Run / experiment:
1 min treatment
Value:
28.25
Vehicle controls validity:
not applicable
Negative controls validity:
not applicable
Positive controls validity:
not applicable
Remarks on result:
other: Timepoint of measurement and of maximum swelling after treatment: 240 min. Corneal swelling is expressed as the percentage increase in thickness compared with the pre-treatment thickness.
Irritation parameter:
other: fluorescein staining
Run / experiment:
1 min treatment
Value:
2
Vehicle controls validity:
not applicable
Negative controls validity:
not applicable
Positive controls validity:
not applicable
Remarks on result:
other: Distinct - Pale continuous staining of the epithelium with slow diffusion into the stroma.
Irritation parameter:
histopathological observations
Run / experiment:
1 min treatment
Value:
>= 1 - <= 7
Vehicle controls validity:
not applicable
Negative controls validity:
not applicable
Positive controls validity:
not applicable
Remarks on result:
other: Loss of corneal cell layers: 1-7 (According to the study report, 8 epithelial cell layers are normal.)

AVERAGE SCORE: 
- Maximum opacity score: 
10 seconds: 1 (scattered/diffuse areas of opacity or loss of corneal epithelium, iris clearly visible)
60 seconds: 2 (easily discernable greyish translucant areas, details of iris slightly obscured)
- Maximum mean swelling: 
10 seconds: 9.30%
60 seconds: 28.25%
- Fluorescein staining: 
10 seconds: marginal (punctate staining across cornea with some evidence of slight diffusion into cornea)
60 seconds: Distinct (pale continuous staining of the epithelium with slow diffucion into the stroma)
- Loss of corneal cell layers: 
10 seconds: 0-2
60 seconds: 1-7 

Interpretation of results:
other: moderately irritating
Endpoint:
eye irritation: in vitro / ex vivo
Type of information:
experimental study
Adequacy of study:
weight of evidence
Study period:
16 Mar - 18 Mar 1993
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
study well documented, meets generally accepted scientific principles, acceptable for assessment
Remarks:
The method is well-documented, but not yet validated. It is currently in use as an alternative to in vivo eye irritation studies for substances which are shown to be irritating in skin irritation tests.
Principles of method if other than guideline:
ex vivo rabbit eye irritation study
GLP compliance:
yes
Remarks:
Environmental Safety Laboratory, Unilever Research, Bedford UK.
Species:
rabbit
Vehicle:
unchanged (no vehicle)
Controls:
other: 2 enucleated eyes served as control
Amount / concentration applied:
undiluted
Amount applied: 50 mg
Duration of treatment / exposure:
1 minute(s)
Observation period (in vivo):
eyes ex vivo were checked 0.5, 1, 2, 3, and 4 h after treatment for opacification of the cornea and corneal thickness
1 h after treatment fluorescein solution was applied and the rate of fluorescein diffusion into the corneal stroma was assessed togehter with possible corneal damage
4 h after treatment eyes were dissected and corneas underwent histological examination
Number of animals or in vitro replicates:
3 rabbit eyes (ex vivo) were treated with the test substance
2 control rabbit eyes (ex vivo) were untreated
Irritation parameter:
cornea opacity score
Run / experiment:
1 min treatment
Value:
4
Vehicle controls validity:
not applicable
Negative controls validity:
not applicable
Positive controls validity:
not applicable
Remarks on result:
other: 4 = Complete corneal opacity, iris not discernible.
Irritation parameter:
percent corneal swelling
Run / experiment:
1 min treatment
Value:
> 0 - < 100
Vehicle controls validity:
not applicable
Negative controls validity:
not applicable
Positive controls validity:
not applicable
Remarks on result:
other: No corneal swelling measurements were taken because of the considerable damage to the corneal surface.
Irritation parameter:
other: fluorescein staining
Run / experiment:
1 min treatment
Value:
4
Vehicle controls validity:
not applicable
Negative controls validity:
not applicable
Positive controls validity:
not applicable
Remarks on result:
other: 4 = Strong - Intense staining of the epithelium and anterior stroma with very rapid diffusion into the remainder of the stroma.
Irritation parameter:
histopathological observations
Run / experiment:
1 min treatment
Value:
>= 4 - <= 7
Vehicle controls validity:
not applicable
Negative controls validity:
not applicable
Positive controls validity:
not applicable
Remarks on result:
other: Loss of corneal cell layers: 4-7 (According to the study report, 8 epithelial cell layers are normal.)

AVERAGE SCORE: 
- Maximum opacity score: 
10 seconds: 1 (scattered/diffuse areas of opacity or loss of corneal epithelium, iris clearly visible)
60 seconds: 4 (complete corneal opacity, iris not discernable)
- Maximum mean swelling: 
10 seconds: 15.91%
60 seconds: Not measurable
- Fluorescein staining: 
10 seconds: marginal (punctate staining across cornea with some evidence of slight diffusion into cornea)
60 seconds: strong (intense staining of the epithelium and anterior stroma with very rapid diffusion into the remiander
of the stroma)
- Loss of corneal cell layers:
10 seconds: 2-4
60 seconds: 4-7 

Interpretation of results:
Category 1 (irreversible effects on the eye) based on GHS criteria
Endpoint:
eye irritation: in vitro / ex vivo
Type of information:
experimental study
Adequacy of study:
weight of evidence
Study period:
16 Mar - 18 Mar 1993
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
study well documented, meets generally accepted scientific principles, acceptable for assessment
Remarks:
The method is well-documented, but not yet validated. It is currently in use as an alternative to in vivo eye irritation studies for substances which are shown to be irritating in skin irritation tests.
Principles of method if other than guideline:
ex vivo rabbit eye irritation study
GLP compliance:
yes
Remarks:
Environmental Safety Laboratory, Unilever Research, Bedford UK.
Species:
rabbit
Details on test animals or tissues and environmental conditions:
TEST ANIMALS:  - Source: Laboratories of Industrial Toxicology, Huntingdon Research Centre Ltd. (HRC)
The eyes were from animals used by HRC in skin irritation tests or were the control eyes from eye irritation tests.
Vehicle:
unchanged (no vehicle)
Controls:
other: 2 untreated eyes served as control
Amount / concentration applied:
undiluted
Amount applied: 50 mg
Duration of treatment / exposure:
1 minute(s)
Observation period (in vivo):
eyes ex vivo were checked 0.5, 1, 2, 3, and 4 h after treatment for opacification of the cornea and corneal thickness
1 h after treatment fluorescein solution was applied and the rate of fluorescein diffusion into the corneal stroma was assessed togehter with possible corneal damage
4 h after treatment eyes were dissected and corneas underwent histological examination
Number of animals or in vitro replicates:
3 rabbit eyes (ex vivo) were treated with the test substance
2 control rabbit eyes (ex vivo) were untreated
Irritation parameter:
cornea opacity score
Run / experiment:
1 min treatment
Value:
ca. 2 - ca. 3
Vehicle controls validity:
not applicable
Negative controls validity:
not applicable
Positive controls validity:
not applicable
Remarks on result:
other: 2 = early discernable greyish transculant areas, details of iris slightly obscured; 3 = grey/ white areas, no details of iris visible, size of pupil barely discernible
Irritation parameter:
percent corneal swelling
Run / experiment:
1 min treatment
Value:
46.56
Vehicle controls validity:
not applicable
Negative controls validity:
not applicable
Positive controls validity:
not applicable
Remarks on result:
other: Timepoint of measurement and of maximum swelling after treatment: 240 min. Corneal swelling is expressed as the percentage increase in thickness compared with the pre-treatment thickness.
Irritation parameter:
other: fluorescein staining
Run / experiment:
1 min treatment
Value:
2
Vehicle controls validity:
not applicable
Negative controls validity:
not applicable
Positive controls validity:
not applicable
Remarks on result:
other: Distinct - Pale continuous staining of the epithelium with slow diffusion into the stroma.
Irritation parameter:
histopathological observations
Run / experiment:
1 min treatment
Value:
>= 1 - <= 7
Vehicle controls validity:
not applicable
Negative controls validity:
not applicable
Positive controls validity:
not applicable
Remarks on result:
other: Loss of corneal cell layers: 1-7 (According to the study report, 8 epithelial cell layers are normal.)

AVERAGE SCORE: 
- Maximum opacity score:
10 seconds: 1 (scattered/diffuse areas of opacity or loss of corneal epithelium, iris clearly visible)
60 seconds: 2/3 (easily discernable greyish transculant areas, details of iris slightly obscured/grey-white areas,
no details of iris visible, size of pupil barely discernable)
- Maximum mean swelling:
10 seconds: 16.28%
60 seconds: 46.56%
- Fluorescein staining: 
10 seconds: marginal (punctate staining across cornea with some evidence of slight diffusion into cornea)
60 seconds: distinct (pale continuous staining of the epithelium with slow diffusion into the stroma).
- Loss of layers: 
10 seconds: 1-3
60 seconds: 1-7

Interpretation of results:
other: irritating to the eye
Endpoint:
eye irritation: in vitro / ex vivo
Type of information:
experimental study
Adequacy of study:
weight of evidence
Study period:
16 Mar - 18 Mar 1993
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
study well documented, meets generally accepted scientific principles, acceptable for assessment
Remarks:
The method is well-documented, but not yet validated. It is currently in use as an alternative to in vivo eye irritation studies for substances which are shown to be irritating in skin irritation tests.
Principles of method if other than guideline:
ex vivo rabbit eye irritation study
GLP compliance:
yes
Remarks:
Environmental Safety Laboratory, Unilever Research, Bedford UK.
Species:
rabbit
Vehicle:
unchanged (no vehicle)
Controls:
other: 2 enucleated eyes served as control
Amount / concentration applied:
undiluted
Amount applied: 50 mg
Duration of treatment / exposure:
1 minute(s)
Observation period (in vivo):
eyes ex vivo were checked 0.5, 1, 2, 3, and 4 h after treatment for opacification of the cornea and corneal thickness
1 h after treatment fluorescein solution was applied and the rate of fluorescein diffusion into the corneal stroma was assessed togehter with possible corneal damage
4 h after treatment eyes were dissected and corneas underwent histological examination
Number of animals or in vitro replicates:
3 rabbit eyes (ex vivo) were treated with the test substance
2 control rabbit eyes (ex vivo) were untreated
Irritation parameter:
cornea opacity score
Run / experiment:
1 min treatment
Value:
1
Vehicle controls validity:
not applicable
Negative controls validity:
not applicable
Positive controls validity:
not applicable
Remarks on result:
other: 1 = scattered/diffuse areas of opacity or loss of corneal epithelium, iris clearly visible
Irritation parameter:
percent corneal swelling
Run / experiment:
1 min treatment
Value:
20.34
Vehicle controls validity:
not applicable
Negative controls validity:
not applicable
Positive controls validity:
not applicable
Remarks on result:
other: Timepoint of measurement and of maximum swelling after treatment: 240 min. Corneal swelling is expressed as the percentage increase in thickness compared with the pre-treatment thickness.
Irritation parameter:
other: fluorescein staining
Run / experiment:
1 min treatment
Value:
1
Vehicle controls validity:
not applicable
Negative controls validity:
not applicable
Positive controls validity:
not applicable
Remarks on result:
other: Marginal = Punctuate staining across cornea with some evidence of slight diffusion into cornea.
Irritation parameter:
histopathological observations
Run / experiment:
1 min treatment
Value:
>= 0 - <= 4
Vehicle controls validity:
not applicable
Negative controls validity:
not applicable
Positive controls validity:
not applicable
Remarks on result:
other: Loss of corneal cell layers: 0-4 (According to the study report, 8 epithelial cell layers are normal.)

AVERAGE SCORE: 
- Maximum opacity score:
10 seconds: 1 (scattered/diffuse areas of opacity or loss of corneal epithelium, iris clearly visible)
60 seconds: 1 (scattered/diffuse areas of opacity or loss of corneal epithelium, iris clearly visible)
- Maximum mean swelling: 
10 seconds: 6.82%
60 seconds: 20.34%
- Fluorescein staining: 
10 seconds: marginal (punctate staining across cornea with some evidence of slight diffusion into cornea)
60 seconds: marginal (punctate staining across cornea with some evidence of slight diffusion into cornea)
- Loss of corneal cell layers: 
10 seconds: 1-3
60 seconds: 0-4 

Interpretation of results:
other: slight irritating potential observed
Endpoint:
eye irritation: in vitro / ex vivo
Type of information:
experimental study
Adequacy of study:
weight of evidence
Study period:
16 Mar - 18 Mar 1993
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
study well documented, meets generally accepted scientific principles, acceptable for assessment
Remarks:
The method is well-documented, but not yet validated. It is currently in use as an alternative to in vivo eye irritation studies for substances which are shown to be irritating in skin irritation tests.
Principles of method if other than guideline:
ex vivo rabbit eye irritation study
GLP compliance:
yes
Remarks:
Environmental Safety Laboratory, Unilever Research, Bedford UK.
Species:
rabbit
Details on test animals or tissues and environmental conditions:
TEST ANIMALS: 
- Source: Laboratories of Industrial Toxicology, Huntingdon Research Centre Ltd. (HRC)
Vehicle:
unchanged (no vehicle)
Controls:
other: 2 enucleated eyes served as control
Amount / concentration applied:
undiluted
Amount applied: 50 mg
Duration of treatment / exposure:
1 minute(s)
Observation period (in vivo):
eyes ex vivo were checked 0.5, 1, 2, 3, and 4 h after treatment for opacification of the cornea and corneal thickness
1 h after treatment fluorescein solution was applied and the rate of fluorescein diffusion into the corneal stroma was assessed togehter with possible corneal damage
4 h after treatment eyes were dissected and corneas underwent histological examination
Number of animals or in vitro replicates:
3 rabbit eyes (ex vivo) were treated with the test substance
2 control rabbit eyes (ex vivo) were untreated
Irritation parameter:
cornea opacity score
Run / experiment:
1 min treatment
Value:
ca. 1 - ca. 2
Vehicle controls validity:
not applicable
Negative controls validity:
not applicable
Positive controls validity:
not applicable
Remarks on result:
other: 1 = scattered/diffuse areas of opacity or loss of corneal epithelium, iris clearly visible; 2 = early discernable greyish transculant areas, details of iris slightly obscured
Irritation parameter:
percent corneal swelling
Run / experiment:
1 min treatment
Value:
19.32
Vehicle controls validity:
not applicable
Negative controls validity:
not applicable
Positive controls validity:
not applicable
Remarks on result:
other: Timepoint of measurement and of maximum swelling after treatment: 240 min. Corneal swelling is expressed as the percentage increase in thickness compared with the pre-treatment thickness.
Irritation parameter:
other: fluorescein staining
Run / experiment:
1 min treatment
Value:
1
Vehicle controls validity:
not applicable
Negative controls validity:
not applicable
Positive controls validity:
not applicable
Remarks on result:
other: Marginal = Punctuate staining across cornea with some evidence of slight diffusion into cornea.
Irritation parameter:
histopathological observations
Run / experiment:
1 min treatment
Value:
>= 0 - <= 4
Vehicle controls validity:
not applicable
Negative controls validity:
not applicable
Positive controls validity:
not applicable
Remarks on result:
other: Loss of corneal cell layers: 0-4 (According to the study report, 8 epithelial cell layers are normal.)

AVERAGE SCORE: 
- Maximum opacity score: 1/2 ((1)scattered/diffuse areas of opacity or loss of corneal epithelium, iris clearly visible/(2) early discernable greyish transculant areas, details of iris slightly obscured)
- Maximum mean swelling: 19.32%
- Fluorescein staining: Marginal (punctate staining across cornea with some evidence of slight diffusion into cornea)
- Loss of corneal cell layers: 0-4 

Interpretation of results:
other: slight irritating potential observed

Additional information

The degree of irritation caused in the studies, indicate that the irritation response is inversely correlated with the molar ratio of sodium silicate; a lower molar ratio SiO2: Na2O leads to a higher irritation score and vice versa. This correlation is superimposed by the concentration effect: lower concentrations will exhibit lower irritancy as compared to higher concentrations of the same molar ratio. The inverse correlation with molar ratio is demonstrated by the studies of Cuthbert and Carr (1985) where sodium silicates of comparable concentrations (38 - 41%) but different molar ratios were tested. Whereas ratios of 2.0 and 2.4 exhibited irritating properties, ratios of 2.8 and 3.3 were not irritating. The concentration effect becomes evident when the irritancy of identical molar ratios but different concentrations are compared. A sodium silicate of MR 2.4 is irritating at 40% and corrosive at 82% (Cuthbert and Carr 1985, Karlsson and Loden 1984).

Sodium silicate can be irritating to corrosive to the skin of rabbits, depending on the molar ratio and concentration. Any effects on the skin decrease with increasing molar ratio, superimposed by increasing irritancy with increasing concentrations.

Due to animal welfare, in vivo eye irritation studies were not conducted since the substance is irritating/corrosive to skin (5.3.1). A series of non-validated in vitro studies indicate the same inverse correlation between molar ratio and irritation that has been observed for skin irritation. The powders of varying molar ratios exhibited effects in enucleated rabbit eyes ranging from severely irritating (MR 2.0, 2.4 and 2.6) to slightly irritating (MR 2.8, 3.0 and 3.3).

Justification for classification or non-classification

DSD: Irritating to corrosive depending on the molar ratio/specific concentration limit.

CLP: Depending on the molar ratio: no classification to skin corrosin/irritation category 1B.