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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.

The new ECHA CHEM database has been released by ECHA, and it now contains all REACH registration data. There are more details on the transition of ECHA's published data to ECHA CHEM here.

Diss Factsheets

Administrative data

acute toxicity: dermal
Type of information:
experimental study
Adequacy of study:
key study
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: Test carried out by GLP compliant laboratory to recognised validated methods by trained personnel
Justification for type of information:
See Document "Laponite Analog justification-BL_6_30_2020.pdf" in Section 13.2 - Toxicokinetic assessment for Synthetic fluorohectorites for justification of read-across.

Data source

Reference Type:
study report
Report date:

Materials and methods

Test guideline
no guideline available
Principles of method if other than guideline:
Six rabbits each received a single dermal application at a dose level of 2g/kg bodyweight. The skin of three animals was abraided and the other three animals skin remained in tact. The test site was occluded for 24 hours after which time the wrap and test material were removed. The animals were observed for pharmacologic activity 1,3,6 and 24 hours after treatment and daily afterwards for 14 days. After this time the rabbits were euthenased and subjected to gross necropsy.
GLP compliance:
Test type:
fixed dose procedure

Test material

Constituent 1
Chemical structure
Reference substance name:
Silicic acid, lithium magnesium sodium salt
EC Number:
EC Name:
Silicic acid, lithium magnesium sodium salt
Cas Number:
Molecular formula:
Synthetic hectorite
Details on test material:
Read-across: Laponite Type 1 (Silicate(2-), hexafluoro-, disodium, reaction products with lithium magnesium sodium silicate) and Laponite Type 2 (silicic acid, lithium magnesium sodium salt) in this case the read across substance, are essentially the same structure except that Type 1 has fluoride incorporated in the structure. They both behave in a similar way in powder form and also when dispersed in water, forming a colloidal gel. At skin pH values of essentially neutral, no hydrolysis from the clay type structure would occur and it would not be expected for there to be any difference in the dermal effect than there is for Laponite T2 .

Test animals

New Zealand White
Details on test animals or test system and environmental conditions:
The rabbits were checked for health issues and acclimatised for at least 7 days prior to test initiation. They were housed in controlled humidity and temperature conditions in a 12 hour day/night cycle. Equal numbers of males / females were used and weighed prior to the test.

Administration / exposure

Type of coverage:
physiological saline
Duration of exposure:
24 hours
2g/kg bodyweight
No. of animals per sex per dose:
Three male, three female

Results and discussion

Effect levels
Dose descriptor:
Effect level:
> 2 000 mg/kg bw
Based on:
test mat.
Clinical signs:
other: One animal suffered diarrhea between 3-6 hours after administration
Gross pathology:
No gross changes observed

Applicant's summary and conclusion

Interpretation of results:
practically nontoxic
Migrated information Criteria used for interpretation of results: EU
This test substance is not toxic dermally to rabbits under the conditions of this test
Executive summary:

Laponite Type 2 (EC 258-476-2) is not toxic dermally to rabbits under the conditions of this test. This test substance is a "read-across" for Laponite Type 1 (EC 285-349-9), their structures being essentially identical with the exception of some ionic substitution within the clay lattice. It is therefore concluded that Laponite Type 1 will not be dermally toxic to rabbits in the same way as for Laponite type 2.