[No public or meaningful name is available]

Basic toxicokinetics

Administrative data

Endpoint:

basic toxicokinetics, other

Remarks:

assessment of toxicokinetic behavior

Type of information:

other: In accordance with REACH Annex VIII (8.8) an assessment of toxicokinetic behavior has been conducted to the extent that can be derived from the relevant available information.

Adequacy of study:

key study

Study period:

The assessment was conducted in August 2019

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Relevant studies were reviewed by a qualified toxicologist with a view to fulfilling the requirements of Annex VIII (8.8).

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2019

Materials and methods

Objective of study:

toxicokinetics

Test guideline

Qualifier:

no guideline required

Principles of method if other than guideline:

In accordance with REACH Annex VIII (8.8) an assessment of toxicokinetic behaviour has been conducted to the extent that can be derived from the relevant available information. The assessment is based on the Guidance on information requirements and chemical safety assessment R.7c: Endpoint specific guidance (ECHA, June 2017)

GLP compliance:

no

Remarks:

Not relevant for assessment

Test material

Test material information

Constituent 1

Reference substance name:

Silicon

EC Number:

231-130-8

EC Name:

Silicon

Cas Number:

7440-21-3

Molecular formula:

Si

IUPAC Name:

Silicon

Constituent 2

Reference substance name:

Magnesium silicate

EC Number:

237-413-2

EC Name:

Magnesium silicate

Cas Number:

13776-74-4

Molecular formula:

H2O3Si.Mg

IUPAC Name:

magnesium(2+) ion oxosilanebis(olate), crystalline

Constituent 3

Reference substance name:

Silicon dioxide

EC Number:

231-545-4

EC Name:

Silicon dioxide

Cas Number:

7631-86-9

Molecular formula:

O2Si

IUPAC Name:

Silicon dioxide, amorphous

Constituent 4

Reference substance name:

Dimagnesium silicate

EC Number:

233-112-5

EC Name:

Dimagnesium silicate

Cas Number:

10034-94-3

Molecular formula:

Mg2O4Si

IUPAC Name:

dimagnesium silicate

impurity 1

Reference substance name:

Carbon

EC Number:

231-153-3

EC Name:

Carbon

Cas Number:

7440-44-0

Molecular formula:

C

IUPAC Name:

Carbon

impurity 2

Reference substance name:

Metallic impurities (Na and S)

IUPAC Name:

Metallic impurities (Na and S)

Test material form:

solid: particulate/powder

Results and discussion

Any other information on results incl. tables

Absorption

The molecular weight of the individual constituents of the substance does not preclude absorption from the gastrointestinal tract following oral ingestion. The water solubility results, based on element analysis, suggest that absorption of Mg and Si could be limited from the gastrointestinal tract following oral ingestion. However, ionised elements (particularly Mg) could diffuse across the gastrointestinal tract relatively freely.

There is limited evidence of absorption from the gastrointestinal tract following oral ingestion from oral toxicity studies. The acute oral toxicity study showed no signs of toxicity. The oral OECD 422 study showed no toxicologically significant effects on body weight, food consumption, clinical signs, clinical pathology, organ weights or histopathology assessments.

The available data suggests that dermal absorption would be low. This is supported by acute dermal toxicity study and LLNA study; neither of which showed any evidence of systemic toxicity.

The substance is not a skin irritant so significant damage to the skin surface should not occur to enhance penetration.

The results of the available acute and repeated dose toxicity studies show no significant evidence of toxicity and there is little to confirm there has been significant absorption of the substance; or the substance is not inherently toxic.

Distribution

 

There is no significant evidence to suggest widespread distribution of the substance will occur.

Significant systemic distribution was not evident from the repeated dose toxicity study.

The lack of skin sensitization response would suggest the substance does not bind to circulatory proteins.

Metabolism

 

The results of the repeated dose toxicity study did not show evidence to indicate any substance influenced hepatic metabolism. Due to the nature of the test item, it can be predicted that metabolism of the test item is not expected due to the simple nature of the product. It is unlikely that this material will require conjugation as a prelude to biliary excretion

 

The results of the genotoxicity assays have shown that genotoxicity is neither enhanced or diminished in the presence of a metabolising system.

Excretion

There is no evidence to indicate the route of excretion but poorly water-soluble products are not favourable for urinary excretion in general but simple structures such as the test item may well be excreted via the kidney unchanged and may not require biliary excretion which is the normal route for poorly water soluble products. Any substance that is not absorbed from the gastrointestinal tract will be excreted in the faeces.

Applicant's summary and conclusion

Conclusions:

The available information suggests that absorption of the test substance from the gastrointestinal tract and absorption via the skin may be limited. There is no significant evidence to suggest widespread distribution of any absorbed substance. There is no evidence to suggest that the test substance may be metabolised.