Diindium trioxide

Basic toxicokinetics

Administrative data

Endpoint:

basic toxicokinetics in vitro / ex vivo

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

test procedure in accordance with generally accepted scientific standards and described in sufficient detail

Remarks:

Test according to state-of-the-art operating procedures for testing of metal bioelution.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2015

Report date:

2015

Materials and methods

Objective of study:

bioaccessibility (or bioavailability)

Test guideline

Qualifier:

according to guideline

Guideline:

other: ASTM D5517-07: Standard Test Method for determining the extractability of metals from art materials - ASTM, 2007 (American Society for Testing and Materials).

Principles of method if other than guideline:

The release/dissolution of indium from Indium(III) oxide in simulated gastric fluid was measured. The resulting value is termed bio-accessibility, and is defined as the fraction of a substance that is soluble under physiological conditions and therefore potentially available for absorption into systemic circulation. The simulated gastric fluid represents an exposure-relevant exposure route (oral exposure). The compound was introduced as powder in a test item / solution ratio of 200 mg/L during 2 hours.

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

Diindium trioxide

EC Number:

215-193-9

EC Name:

Diindium trioxide

Cas Number:

1312-43-2

Molecular formula:

In2O3

IUPAC Name:

bicyclo[1.1.1]diindoxane

Test material form:

solid: particulate/powder

Remarks:

migrated information: powder

Details on test material:

- Product name: Indium(III) oxide
- Physical state: solid (powder), yellow
- Purity: 99.996%
- Lot/batch No.: OX-2857
- Expiration date of the lot/batch: stable over time
- Storage condition of test material: room temperature, in the dark
- Particle size (typical): d90<8.62μm; d50<4.23μm; d10<1.43μm
- Specific surface area: 0.81 m²/g

Results and discussion

Preliminary studies:

not applicable

Main ADME results

Type:

other: bioaccessibility

Results:

gastric fluid (2hours): as %In released of total In content: 0.15

Toxicokinetic / pharmacokinetic studies

Details on absorption:

not applicable

Details on distribution in tissues:

not applicable

Details on excretion:

not applicable

Metabolite characterisation studies

Metabolites identified:

not measured

Details on metabolites:

not applicable

Bioaccessibility (or Bioavailability)

Bioaccessibility (or Bioavailability) testing results:

gastric fluid (2hours): as %In released of total In content: 0.15

Any other information on results incl. tables

Indium(III) oxide, loading 0.2 g/L              2h gastric at pH 1.5
Analyte                                                              X±σ                        CV
Indium (In)	dissolution	243 ± 32 μg/L	13%
	eluted	1210 ± 157 μg/g	13%
% Indium eluted		0.15%

X= Average of 3 test vessels (0.2µm filtration)

σ = Standard deviation

CV: Coefficient of variation (%)

Applicant's summary and conclusion

Conclusions:

Bio-elution test according to state-of-the-art procedures, useful for determining dissolution capacity of In in gastric fluid.
Interpretation of results: Low bioaccessibility of In from Indium(III) oxide. The dissolution in gastric fluid is used to estimate bioavailability after oral exposure

Executive summary:

During this study on Indium(III) oxide at a loading of 0.2 g/L in simulated gastric fluid (pH 1.5), it was shown that significant amounts of indium were measured. For indium an average value of 243 μg/L In (CV=13%) or 1210 μg In per g test item was found after 2 hours of extraction, corresponding with a indium release per surface of 1.49 mg/m² or an indium release of 0.15% (based on the specific surface area of Indium(III) oxide (0.81 m²/g) or on the available amount of indium (82.7%, molecular formula))