Silicic acid, aluminum sodium salt

Endpoint summary

Description of key information

Skin Irritation

The two studies in skin irritation with the test substance Silicic acid, aluminum sodium salt (CAS 1344-00-9, NAS) showed no evidence of erythema or edema.

The studies in the structurally related read-across substances showed only mild responses not meeting GHS criteria for classification.

 

Eye Irritation

There is only one reliable study in one nanoform of Silicic acid, aluminum sodium salt (CAS 1344-00-9, NAS) which produced only slight and short-term irritation, not meeting GHS criteria for classification. A second study in the same form of substance, that did not show ocular irritation, cannot be used for classification, because contradictory to the current guideline the eyes were rinsed. Another study in two other forms of Silicic acid, aluminum sodium salt (CAS 1344-00-9, NAS) also cannot be used for classification, since there are no individual animal scores provided in its report. But it produced in any case only mild and reversible effects. Yet another study in another form of Silicic acid, aluminum sodium salt (CAS 1344-00-9, NAS) is also unassessable for classification due to ambiguous results making impossible a stand-alone prediction according to OECD 491.
An in-vitro study in the structurally related read-across substance Silicic acid, aluminum magnesium sodium salt (CAS 12040-43-6, SMAS) measured a relative tissue viability of 88.7%, thereby not meeting GHS criteria for classification.

Key value for chemical safety assessment

Skin irritation / corrosion

Link to relevant study records

Reference

Reference 1

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:

test procedure in accordance with national standard methods with acceptable restrictions

Qualifier:

according to guideline

Guideline:

other: U.S. Fed. Hazardous Substances Act, Section 101.11

GLP compliance:

not specified

Specific details on test material used for the study:

Zeolex 7

Species:

rabbit

Strain:

New Zealand White

Type of coverage:

semiocclusive

Preparation of test site:

other: abraded and intact (shaved)

Vehicle:

not specified

Amount / concentration applied:

0.5 g

Duration of treatment / exposure:

24 h

Observation period:

Scoring after 24 and 72 h after test initiation

Number of animals:

6

Details on study design:

The procedure described in Section 101.11 of the Federal Hazardous Substances Act was followed. Irritation to the skin was measured by the patch test technique using the albino rabbit. Six healthy New Zealand rabbits were used to determine the irritation potential of each test material. Each animal received two applications of the assigned test material; one application to an intact and one application to an abraded skin area clipped free of hair. Surgical gauze (1 inch x 1 inch) secured in place by adhesive tape was used to cover the treated sites. Each animal received 0.5 grams of test material at each test site.

The entire trunk of each animal was then wrapped in plastic to prevent loss of the sample. Contact of the test material with the skin was maintained for 24 hours, after which the plastic and gauze were removed and the treated areas gently cleansed. The treated areas were scored according to the Federal Hazardous Substances Act, 24 and 72 hours after initiation of the test.

Irritation parameter:

primary dermal irritation index (PDII)

Basis:

mean

Time point:

other: 24 / 72 h

Score:

0

Remarks on result:

no indication of irritation

Irritation parameter:

edema score

Basis:

animal: #1 - #6

Time point:

72 h

Score:

0

Remarks on result:

no indication of irritation

Irritation parameter:

edema score

Basis:

animal: #1 - #6

Time point:

24 h

Score:

0

Remarks on result:

no indication of irritation

Irritation parameter:

erythema score

Basis:

animal: #1 - #6

Time point:

72 h

Score:

0

Remarks on result:

no indication of irritation

Irritation parameter:

erythema score

Basis:

animal: #1 - #6

Time point:

24 h

Score:

0

Remarks on result:

no indication of irritation

Irritant / corrosive response data:

No evidence of erythema or edema was observed following topical application of the test material to any of the rabbits.

Interpretation of results:

GHS criteria not met

Conclusions:

No evidence of erythema or edema was observed following topical application of the test material to any of the rabbits.

Executive summary:

The skin irritation potential of the Sodium silicoaluminate Zeolex 7 was investigated in six rabbits according to the Federal Hazardous Substances Act. No evidence of erythema or edema was observed within 72 hours.

Reference 2

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:

test procedure in accordance with national standard methods with acceptable restrictions

Qualifier:

according to guideline

Guideline:

other: U.S. Fed. Hazardous Substances Act, Section 101.11

GLP compliance:

not specified

Specific details on test material used for the study:

Zeolex 23A

Species:

rabbit

Strain:

New Zealand White

Type of coverage:

semiocclusive

Preparation of test site:

other: abraded and intact (shaved)

Vehicle:

not specified

Amount / concentration applied:

0.5 g

Duration of treatment / exposure:

24 h

Observation period:

Scoring after 24 and 72 h after test initiation

Number of animals:

6

Details on study design:

The procedure described in Section 101.11 of the Federal Hazardous Substances Act was followed. Irritation to the skin was measured by the patch test technique using the albino rabbit. Six healthy New Zealand rabbits were used to determine the irritation potential of each test material. Each animal received two applications of the assigned test material; one application to an intact and one application to an abraded skin area clipped free of hair. Surgical gauze (1 inch x 1 inch) secured in place by adhesive tape was used to cover the treated sites. Each animal received 0.5 grams of test material at each test site.

The entire trunk of each animal was then wrapped in plastic to prevent loss of the sample. Contact of the test material with the skin was maintained for 24 hours, after which the plastic and gauze were removed and the treated areas gently cleansed. The treated areas were scored according to the Federal Hazardous Substances Act, 24 and 72 hours after initiation of the test.

Irritation parameter:

primary dermal irritation index (PDII)

Basis:

mean

Time point:

other: 24 / 72 h

Score:

0

Remarks on result:

no indication of irritation

Irritation parameter:

edema score

Basis:

animal: #1 - #6

Time point:

72 h

Score:

0

Remarks on result:

no indication of irritation

Irritation parameter:

edema score

Basis:

animal: #1 - #6

Time point:

24 h

Score:

0

Remarks on result:

no indication of irritation

Irritation parameter:

erythema score

Basis:

animal: #1 - #6

Time point:

72 h

Score:

0

Remarks on result:

no indication of irritation

Irritation parameter:

erythema score

Basis:

animal: #1 - #6

Time point:

24 h

Score:

0

Remarks on result:

no indication of irritation

Irritant / corrosive response data:

No evidence of erythema or edema was observed following topical application of the test material to any of the rabbits.

Interpretation of results:

GHS criteria not met

Conclusions:

No evidence of erythema or edema was observed following topical application of the test material to any of the rabbits.

Executive summary:

The skin irritation potential of the Sodium silicoaluminate Zeolex 23A was investigated in six rabbits according to the Federal Hazardous Substances Act. No evidence of erythema or edema was observed within 72 hours.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not irritating)

Eye irritation

Link to relevant study records

Reference

Reference 1

Endpoint:

eye irritation: in vitro / ex vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

Sep. 6-18, 2019, experimental phase: Sep. 9-12, 2019

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Qualifier:

according to guideline

Guideline:

OECD Guideline 492 (Reconstructed Human Cornea-like Epithelium (RhCE) Test Method for Identifying Chemicals Not Requiring Classification and Labelling for Eye Irritation or Serious Eye Damage)

Version / remarks:

2019

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Specific details on test material used for the study:

Name: Silicic acid, magnesium aluminium sodium salt
Batch no.: 1901274010
Appearance: white fluffy powder
Composition: Sodium; Magnesium; Aluminium; Silica
Purity: >95%
Homogeneity: homogeneous

Controls:

yes, concurrent positive control

yes, concurrent negative control

Duration of treatment / exposure:

6 h

Duration of post- treatment incubation (in vitro):

18 h

Number of animals or in vitro replicates:

2

Details on study design:

- Negative Control: Sterile demineralised water, prepared by LAUS GmbH using an ion exchanger and membrane filtration through sterile filters, batch no.: T20190717.
- Positive Control: Methyl acetate (C3H6O2, CAS No. 79-20-9), procured from MatTek, batch no.: 021319ISC.
- Test System: Commercially available EpiOcular(TM) kit.
The EpiOcular tissue consists of normal, human-derived keratinocytes which have been cultured to form a stratified squamous epithelium similar to that found in the human cornea. It consists of highly organized basal cells. These cells are not transformed or transfected with genes to induce an extended life span. The EpiOcular tissues are cultured in specially prepared cell culture inserts with a porous membrane through which nutrients can pass to the cells. The tissue surface is 0.6 cm².
- MTT solution: 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazoliumbromide (=MTT), which can be reduced to a blue formazan, prepared by LAUS GmbH.
A MTT stock solution of 5 mg/mL in DPBS buffer was prepared and stored in aliquots of 2 mL at – 20 ± 5 °C. 2 mL of the stock solution were thawed and diluted with 8 mL of assay medium (resulting in 1 mg/mL). This MTT-solution with the concentration of 1 mg/mL was used in the test.

Irritation parameter:

in vitro irritation score

Run / experiment:

relative tissue viability

Value:

ca. 86.3 - ca. 91

Negative controls validity:

valid

Positive controls validity:

valid

Remarks on result:

no indication of irritation

Measured Values

As blank, the optical density of isopropanol was measured in eight wells of the 96-well-plate. The measured values and their mean are given in the following table:

Table 9.1-a : Absorbance Values Blank Isopropanol (OD at 570 nm)

Replicate              1              2               3               4             5             6             7             8              Mean

Absorbance       0.032       0.033       0.033       0.034       0.034       0.034       0.033       0.035       0.034

The absorbance values of negative control, test item and positive control are given in the following table:

Table 9.1-b: Absorbance Values Negative Control, Positive Control and Test Item (OD at 570 nm)

Designation        Measurement        Negative Control        Positive Control       Silicic acid, magnesium aluminium                                                                                                                                                   sodium salt

Tissue 1                    1                            1.878                     0.791                                          1.671

2                            1.889                     0.772                                          1.658

Tissue 2                    1                            1.771                     0.866                                          1.586

2                            1.761                     0.859                                          1.574

From the measured absorbances, the mean of each tissue was calculated, subtracting the mean absorbance of isopropanol as given in table 9.1-a (= corrected values).

Table 9.1-c: Mean Absorbance Negative Control, Positive Control and Test Item

Designation                     Negative Control        Positive Control        Silicic acid, magnesium aluminium sodium salt

Mean – blank (Tissue 1)       1.850                            0.748                                          1.631

Mean – blank (Tissue 2)       1.732                            0.829                                          1.546

Comparison of Tissue Viability

For the test item and the positive control, the following percentage values of tissue viability were calculated in comparison to the negative control:

Table 9.2-a: % Viability Positive Control and Test Item

Designation                     Positive Control               Silicic acid, magnesium aluminium sodium salt

% Viability (Tissue 1)              41.7%                                                 91.0%

% Viability (Tissue 2)              46.3%                                                 86.3%

% Viability Mean                     44.0%                                                88.7%

Eye hazard potential was assessed using the criteria given in the following table:

Table 9.3-a: Assessment of Eye Hazard Potential

% Viability               Assessment               UN GHS classification

> 60 %                    Non eye irritant              No Category

≤ 60 %                   At least eye irritant         No prediction can be made (category 1 or 2)

Validity criteria and results are stated in the following table:

Table 9.4 -a:

Validity                                           CriterionDemanded                                           Found    

Mean OD of negative control              > 0.8 and < 2.8                                                 1.8

% mean relative viability of

positive control                                   < 50% of negative control                                 44.0%

Variation within replicates                   < 20%                                                              6.6% (negative control)

4.5% (positive control)

4.7% (test item)

Values for negative control and for positive control were within the range of historical data of the test facility.

Therefore, the experiment was considered valid.

Interpretation of results:

GHS criteria not met

Conclusions:

Under the conditions of the test, Silicic acid, aluminum magnesium sodium salt (CAS 12040-43-6, SMAS) is considered non-eye irritant in the EpiOcular(TM) Eye Irritation Test.

Executive summary:

The test item Silicic acid, aluminum magnesium sodium salt (CAS 12040-43-6, SMAS) was applied to a three-dimensional human cornea tissue model in duplicate for an exposure time of 6 hours.

Reference 2

Endpoint:

eye irritation: in vivo

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

test procedure in accordance with national standard methods with acceptable restrictions

Qualifier:

according to guideline

Guideline:

other: Fed. Hazardous Substance Act Section 191.12 (1973)

GLP compliance:

not specified

Specific details on test material used for the study:

Zeolex 23A

Species:

rabbit

Strain:

New Zealand White

Vehicle:

unchanged (no vehicle)

Amount / concentration applied:

100 mg

Duration of treatment / exposure:

once, unrinsed

Observation period (in vivo):

72 hours

Number of animals or in vitro replicates:

6

Details on study design:

A single application of the test sample (100 mg of a solid) full strength was made into the conjunctival sac of the right eye of six rabbits. The eyelids were held closed for one second. The left eye served as the control.
The eyes were examined and the grade of ocular reaction recorded at 24, 48 and 72 hours following application. Reading of reactions was facilitated by the use of a hand-held ophthalmoscope. After the recording of observations, the eyes were stained with sodium fluorescein and examined with an ultra-violet lamp to detect possible corneal damage.
The reactions were based on the " Illustrated Guide for Grading Eye Irritation by Hazardous Sabstances", Federal Hazardous Substances Act Regulations.

Irritation parameter:

chemosis score

Basis:

animal #6

Time point:

24/48/72 h

Score:

0

Max. score:

4

Irritation parameter:

chemosis score

Basis:

animal #5

Time point:

72 h

Score:

0

Max. score:

4

Irritation parameter:

chemosis score

Basis:

animal #5

Time point:

48 h

Score:

0

Max. score:

4

Irritation parameter:

chemosis score

Basis:

animal #5

Time point:

24 h

Score:

1

Max. score:

4

Reversibility:

fully reversible within: 48 h

Irritation parameter:

chemosis score

Basis:

animal #4

Time point:

72 h

Score:

0

Max. score:

4

Irritation parameter:

chemosis score

Basis:

animal #4

Time point:

48 h

Score:

0

Max. score:

4

Irritation parameter:

chemosis score

Basis:

animal #4

Time point:

24 h

Score:

1

Max. score:

4

Reversibility:

fully reversible within: 48 h

Irritation parameter:

chemosis score

Basis:

animal #3

Time point:

72 h

Score:

0

Max. score:

4

Irritation parameter:

chemosis score

Basis:

animal #3

Time point:

48 h

Score:

0

Max. score:

4

Irritation parameter:

chemosis score

Basis:

animal #3

Time point:

24 h

Score:

1

Max. score:

4

Reversibility:

fully reversible within: 48 h

Irritation parameter:

chemosis score

Basis:

animal #2

Time point:

24/48/72 h

Score:

0

Max. score:

4

Irritation parameter:

chemosis score

Basis:

animal #1

Time point:

72 h

Score:

0

Max. score:

4

Irritation parameter:

chemosis score

Basis:

animal #1

Time point:

48 h

Score:

0

Max. score:

4

Irritation parameter:

chemosis score

Basis:

animal #1

Time point:

24 h

Score:

1

Max. score:

4

Reversibility:

fully reversible within: 48 h

Irritation parameter:

conjunctivae score

Basis:

animal #6

Time point:

24/48/72 h

Score:

0

Max. score:

0

Irritation parameter:

conjunctivae score

Basis:

animal #5

Time point:

72 h

Score:

0

Max. score:

3

Irritation parameter:

conjunctivae score

Basis:

animal #5

Time point:

48 h

Score:

0

Max. score:

3

Irritation parameter:

conjunctivae score

Basis:

animal #5

Time point:

24 h

Score:

1

Max. score:

3

Reversibility:

fully reversible within: 48 h

Irritation parameter:

conjunctivae score

Basis:

animal #4

Time point:

72 h

Score:

0

Max. score:

3

Irritation parameter:

conjunctivae score

Basis:

animal #4

Time point:

48 h

Score:

0

Max. score:

3

Irritation parameter:

conjunctivae score

Basis:

animal #4

Time point:

24 h

Score:

2

Max. score:

3

Reversibility:

fully reversible within: 48 h

Irritation parameter:

conjunctivae score

Basis:

animal #3

Time point:

72 h

Score:

0

Max. score:

3

Irritation parameter:

conjunctivae score

Basis:

animal #3

Time point:

48 h

Score:

0

Max. score:

3

Irritation parameter:

conjunctivae score

Basis:

animal #3

Time point:

24 h

Score:

1

Max. score:

3

Reversibility:

fully reversible within: 48 h

Irritation parameter:

conjunctivae score

Basis:

animal #2

Time point:

72 h

Score:

0

Max. score:

3

Irritation parameter:

conjunctivae score

Basis:

animal #2

Time point:

48 h

Score:

0

Max. score:

3

Irritation parameter:

conjunctivae score

Basis:

animal #2

Time point:

24 h

Score:

1

Max. score:

3

Reversibility:

fully reversible within: 48 h

Irritation parameter:

conjunctivae score

Basis:

animal #1

Time point:

72 h

Score:

0

Max. score:

3

Irritation parameter:

conjunctivae score

Basis:

animal #1

Time point:

48 h

Score:

0

Max. score:

3

Irritation parameter:

conjunctivae score

Basis:

animal #1

Time point:

24 h

Score:

1

Max. score:

3

Reversibility:

fully reversible within: 48 h

Irritation parameter:

iris score

Basis:

animal #6

Time point:

24/48/72 h

Score:

0

Max. score:

2

Irritation parameter:

iris score

Basis:

animal #5

Time point:

24/48/72 h

Score:

0

Max. score:

2

Irritation parameter:

iris score

Basis:

animal #4

Time point:

24/48/72 h

Score:

0

Max. score:

2

Irritation parameter:

iris score

Basis:

animal #3

Time point:

24/48/72 h

Score:

0

Max. score:

2

Irritation parameter:

iris score

Basis:

animal #2

Time point:

24/48/72 h

Score:

0

Max. score:

2

Irritation parameter:

iris score

Basis:

animal #1

Time point:

24/48/72 h

Score:

0

Max. score:

2

Irritation parameter:

cornea opacity score

Basis:

animal #6

Time point:

24/48/72 h

Score:

0

Max. score:

4

Irritation parameter:

cornea opacity score

Basis:

animal #5

Time point:

24/48/72 h

Score:

0

Max. score:

4

Irritation parameter:

cornea opacity score

Basis:

animal #4

Time point:

24/48/72 h

Score:

0

Max. score:

4

Irritation parameter:

cornea opacity score

Basis:

animal #3

Time point:

24/48/72 h

Score:

0

Max. score:

4

Irritation parameter:

cornea opacity score

Basis:

animal #2

Time point:

24/48/72 h

Score:

0

Max. score:

4

Irritation parameter:

cornea opacity score

Basis:

animal #1

Time point:

24/48/72 h

Score:

0

Max. score:

4

Irritant / corrosive response data:

Only on day 1, effect scores of 1 for conjunctivae and chemosis were observed in many animals, and in one animal score 2 for conjunctivae. Cornea and iris remained unaffected. No irritating effects were seen anymore after 48 h or later.

Interpretation of results:

not irritating

Conclusions:

Based on the results of this study, Zeolex 23A would not be considered an ocular irritant.

Executive summary:

Zeolex 23 A was tested according to the regulations of the Federal Hazardous Substances Act without rinsing. According to this and also modern GHS it would not be considered an ocular irritant.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not irritating)

Respiratory irritation

Endpoint conclusion

Endpoint conclusion:

no study available

Justification for classification or non-classification

The studies in skin irritation in various nanoforms of Silicic acid, aluminum sodium salt (CAS 1344-00-9, NAS) showed no evidence of erythema or edema. Therefore, there is no need for classification.

Concerning the studies in eye irritation, no adverse effects were observed which would lead to classification according to GHS, no hazard was identified and classification is not justified.