Silicic acid, sodium salt

Endpoint summary

Key value for chemical safety assessment

Skin sensitisation

Link to relevant study records

Reference

Endpoint:

skin sensitisation: in vivo (LLNA)

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 429 (Skin Sensitisation: Local Lymph Node Assay)

Deviations:

yes

Remarks:

1-fluoro-2,4-dinitrobenzene (DNFB) as positive control

GLP compliance:

not specified

Type of study:

mouse local lymph node assay (LLNA)

Species:

mouse

Strain:

Balb/c

Sex:

female

Details on test animals and environmental conditions:

TEST ANIMALS:
- Source: National Cancer Institute, USA
- Age: 45 - 60 days
- Weight at study initiation: 17 - 20 g

Vehicle:

other: 15% ethanol

Concentration:

2, 4 and 6%

Details on study design:

RANGE FINDING TESTS:
- Irritation: A primary irritancy assay was performed to establish the minimal irritating and the maximal non-irritating concentration.

TREATMENT PREPARATION AND ADMINISTRATION:
Test solutions were prepared daily in amber vials using 15% ethanol.

Positive control substance(s):

other: 1-fluoro-2,4-dinitrobenzene (DNFB)

Statistics:

Bartlett's chi-square Test, one-way ANOVA and Dunnett's Multiple Range t Test

Parameter:

other: increase of cell proliferation [%]

Remarks:

value of highest non-irritating test substance concentration: 4%

Value:

40

Parameter:

SI

Test group / Remarks:

2%

Remarks on result:

other: No data on SI according to OECD TG 429 are given.

Parameter:

SI

Test group / Remarks:

4%

Remarks on result:

other: No data on SI according to OECD TG 429 are given.

Parameter:

SI

Test group / Remarks:

6%

Remarks on result:

other: No data on SI according to OECD TG 429 are given.

RESULTS OF PILOT STUDY: minimal irritating concentration: 6%; maximal  non-irritating concentration: 4%

 
RESULTS OF TEST
- Sensitization reaction: sensitization with 2-6% did not significantly  alter cell proliferation in the auricular lymph nodes,

even though an  increase of 30% and 40% at the 4% and 6% treatment levels was measured,  respectively. A greater than

30-fold increase was measured in the  positive control.

Interpretation of results:

not sensitising

Endpoint conclusion

Additional information:

The read-across substance, sodium metasilicate, was not sensitizing in the local lymph node assay. In a human case report, contact urticaria induced by sodium silicate was observed in one individual.

Migrated from Short description of key information:
Based on the category approach, sodium silicate is not sensitising.

Respiratory sensitisation

Endpoint conclusion

Additional information:

Not required. No data available.

Justification for classification or non-classification

The available data is conclusive but not sufficient for classification.