Silicate(2-), hexafluoro-, disodium, reaction products with lithium magnesium sodium silicate

Acute Toxicity: dermal

Administrative data

Endpoint:

acute toxicity: dermal

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

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

Reference Type:

study report

Title:

Unnamed

Year:

1988

Report date:

1988

Materials and methods

Test guideline

Qualifier:

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:

yes

Test type:

fixed dose procedure

Test material

Test material information

Constituent 1

Reference substance name:

Silicic acid, lithium magnesium sodium salt

EC Number:

258-476-2

EC Name:

Silicic acid, lithium magnesium sodium salt

Cas Number:

53320-86-8

Molecular formula:

Na0.7[Li0.3Mg5.5Si8O20(OH)4]

IUPAC Name:

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

Species:

rabbit

Strain:

New Zealand White

Sex:

male/female

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:

occlusive

Vehicle:

physiological saline

Duration of exposure:

24 hours

Doses:

2g/kg bodyweight

No. of animals per sex per dose:

Three male, three female

Results and discussion

Effect levels

Sex:

male/female

Dose descriptor:

LD50

Effect level:

> 2 000 mg/kg bw

Based on:

test mat.

Mortality:

None

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

Remarks:

Migrated information Criteria used for interpretation of results: EU

Conclusions:

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.