[No public or meaningful name is available]

Basic toxicokinetics

Administrative data

Endpoint:

basic toxicokinetics in vitro / ex vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

Study plan: 27/07/2018
Draft report: 31/01/2019
Final report: 18/02/2019

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Meets generally accepted scientific standards, well documented and acceptable for assessment.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2019

Report date:

2019

Materials and methods

Objective of study:

bioaccessibility (or bioavailability)

Test guideline

Qualifier:

according to guideline

Guideline:

other: Standard Operating Procedure (SOP) for Bioelution Testing of Metals, Inorganic Metal Compounds, and MetalContaining Complex Materials: Simulated Gastric Fluid

Version / remarks:

Eurometaux, February 16, 2018

Deviations:

yes

Remarks:

The samples were preserved by adding 0.12 mL concentrated HNO3 per 12 mL instead of no preservation in the SOP.

Principles of method if other than guideline:

Bio-elution refers to the in vitro extraction methods used to measure the degree to which a substance
(e.g., metal or mineral ion) is dissolved in artificial biological fluids. Simulated biological fluids represent
relevant exposure routes. The resulting value is the “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 objective of this study was to obtain knowledge about the bio-elution characteristics of G726A-HDE
in simulated gastric fluid. This study has been conducted according to the recommended Standard
Operating Procedure (SOP) for Bioelution Testing of Metals, Inorganic Metal Compounds, and MetalContaining Complex Materials: Simulated Gastric Fluid (Eurometaux, February 16, 2018) which is based
on ASTM D5517-07: Standard Test method for determining the extractability of metals from art materials
- ASTM, 2007 (American Society for Testing and Materials). The extent of dissolution of G726A-HDE as
received, was tested in a simulated gastric fluid at 37 °C and pH 1.5 for 2 hours (0.2 g/L and 2 g/L loading)
at an agitation speed of 100 revolutions per minute (rpm) for 1 hour followed by 1 hour of settling
(without shaking). The bio-elution endpoints were based on the dissolved lead (Pb), tellurium (Te) and tungsten (W) concentrations obtained after 2 hours of extraction.
The following deviation from the SOP was made:
• The samples were preserved by adding 0.12 mL concentrated HNO3 per 12 mL instead of no
preservation in the SOP.
The study was performed at ECTX. Analysis of the concentrations of dissolved lead, tellurium and tungsten has been performed at WLN Business B.V. (The Netherlands), an ISO 17025 accredited laboratory, as delegated by ECTX.
The measured pH of the test medium at the start of the test was 1.50, i.e. within the specifications of
pH 1.5 ± 0.1. The pH measured in the additional test item vessel at the start of the test was 1.50 for both
loadings, 0.2 g/L and 2 g/L, i.e. within the specifications of pH 1.5 ± 0.1. At the 2 hours sampling point of
the test, the pH in the blank control vessel and the test item vessels was between 1.50 and 1.53.
The temperature of the sampled test solutions including the blank test vessel was between 36.9 °C and
37.0 °C and corresponded to the required test conditions of 37 °C ± 1 °C.The blank control vessel showed no concentrations of lead, tellurium and tungsten above the limit of quantification (i.e. accredited reporting limit) of 0.5 µg/L Pb, 0.5 µg/L Te and 0.5 µg/L W.

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

Amorphous bismuth tungsten lead tellurite

Molecular formula:

Not applicable for UVCB substances

IUPAC Name:

Amorphous bismuth tungsten lead tellurite

Test material form:

solid: bulk

Specific details on test material used for the study:

The test item, G726A-HDE as received fulfilled the recommended <100 µm particle size. Therefore, no further preparation of the test item was needed. The Sponsor also provided the required document with the characteristics of the test item (Certificate of Analysis, MSDS)

Element(s) of interest: Lead, tellurium and tungsten
Chemical analysis regarding the elements of interest:
1. 33.5 % PbO (i.e. 31.1 % Pb)
2. 45.6 % TeO2 (i.e. 36.5 % Te)
3. 8.38 % WO3 (i.e. 6.65 % W)
Physical form: Solid, (in the powder form)
Colour: White
Particle size distribution (volume): d10: 0.35 µm d50: 1.08 µm d90: 2.71 µm
A certificate of analysis of the particle size distribution is added to this study report.
Specific surface area (N-BET): 2.93 m²/g
Homogeneous: Yes
Density: n.a.
Storage conditions
Room temperature, in the dark.

Radiolabelling:

no

Test animals

Species:

other: not applicable

Strain:

other: not applicable

Details on test animals or test system and environmental conditions:

Not applicable

Administration / exposure

Route of administration:

other: not applicable

Vehicle:

other: not applicable

Duration and frequency of treatment / exposure:

Not applicable

No. of animals per sex per dose / concentration:

Not applicable

Control animals:

other: not applicable

Positive control reference chemical:

Not applicable

Details on study design:

Test set-up
One PETG Erlenmeyer flask of 250 mL was used for the blank control vessel without test item. For each loading, 0.2 g/L and 2 g/L, 10 mg and 100 mg test item were weighed in triplicate into three separate 250 mL Erlenmeyer flasks. For each loading, a fourth replica with test item (named replica X) was prepared only for the measurement of the initial pH (at the start of the test). This additional test vessel was set up to avoid cross contaminations and did not have further utility in the test. 50 mL of extraction fluid (at 37 °C ± 1 °C) was added to the blank control vessel and each test item vessel resulting in a final loading of 0.2 g/L and 2 g/L, respectively. After covering the vessels with a screwcap and swirling the flasks to mix the test item and the medium, the flasks were placed into a thermostatic orbital shaker (37 °C ± 1 °C) at an agitation rate of 100 revolutions per minute for one hour. After that, the flasks were settled at 37 °C ± 1 °C for another hour.
Sampling during the test
The following sampling procedure was used at the sampling time to collect and preserve the samples for ICP-MS analyses: At the end of the incubation period (2 hours = 1 hour shaking at 100 rpm and 1 hour settling), each vessel was swirled to homogenise the solution prior to sampling, in order to avoid a concentration gradient after settling. Sampling was performed for the blank control and each test item vessel as indicated in the sampling scheme below. In each test vessel, a 12-mL sample was taken twice with a 12 mL syringe from the test vessel at a depth of two-thirds of the supernatant. The samples were filtrated through a 0.2 µm syringe filter and transferred to uniquely labelled 15-mL PP sample tubes. The samples were preserved by adding 0.12 mL concentrated HNO3 per 12 mL. The samples were covered (to avoid evaporation and concentration) and stored at room temperature in the dark until shipment to the Test Site (see 3.3 Test Site identification).
Observations and measurement of temperature and pH
At the start of the test (0h), pH was measured in the additional (fourth) replica with test item of each loading (named replica X). The addition of the test item to the test system had no significant influence on the initial pH of the test system. After sampling, temperature and pH were measured in the remaining blank control and test solutions after sampling.
Shipment of the samples to the Test Site
The samples and datasheet DSH026 Sample Transfer (external), which contains a chain of custody and a detailed sample list with storage conditions were transferred to the Test Site (see 3.3 Test Site identification) in an appropriate manner according to SOP AB-14 (see 5.2.1 SOPs of ECTX).
Analyses of the samples by the Test Site
The determination of dissolved lead, tellurium and tungsten concentrations in the blank control and test item vessels were carried out at the Test Site (see 3.3 Test Site identification), using an ICP-MS (SOP WLNCM.W.11.1 Elemental determination by ICP-MS technique, SFS-EN ISO 17294-2). To describe the dissolution behaviours, even below the accredited reporting limits of WLN and to allow more accurate toxicity calculations, raw data were used to perform calculations. Rounded values were used to at least one more decimal place than the corresponding accredited reporting limit of WLN, if relevant. The ECTX (Ecotoxicology and Biodegradation) TB-2018-R-TB X02A-184 section IV – page 17 from 44 accredited reporting limit with an accuracy of 90 % and 110 % for lead, tellurium and tungsten is 0.5 µg/L.
For values between the detection limit and the accredited reporting limit, an accuracy of 90 % - 110 % cannot be guaranteed.
The analyses were not performed in compliance with the GLP principles, but according to the ISO 17025 standard. Each sample, possibly after proper dilution, was measured once.

Details on dosing and sampling:

Not applicable

Statistics:

Not applicable

Results and discussion

Preliminary studies:

Not applicable

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

Any other information on results incl. tables

Bioaccessibility results

The temperature of the sampled test solutions including the blank test vessel was between 36.9 °C and 37.0 °C and corresponded to the required test conditions of 37 °C ± 1 °C.

The measured pH of the test medium at the start of the test was 1.50, i.e. within the specifications of pH 1.5 ± 0.1. The pH measured in the additional test item vessel at the start of the test was 1.50 and 1.51 for the 0.2 g/L and 2 g/L loading respectively i.e. within the specifications of pH 1.5 ± 0.1. At the 2 hours sampling point of the test, the pH in the blank control vessel and the test item vessels was between 1.50 and 1.52.

The blank control vessel showed no concentrations of lead, tellurium and tungsten above the limit of quantification (i.e. accredited reporting limit) of 0.5 µg/L Pb, 0.5 µg/L Te and 0.5 µg/L W.

The following observations could be made in the test vessels with a loading of 0.2 g/L G726A-HDE:

Test Substance	Gastric Bioaccessibility- 2 hours (mg/l)	surface area (m2/g)	release per surface (mg/m2)	Gastric Bioaccessibility- 2 hours as % released of total content
Lead	17.8	2.93	30	29
Tellurium	12.4	2.93	21	17
Tungsten	0.332	2.93	0.57	2.5

 

The following observations could be made in the test vessels with a loading of 2 g/L G726A-HDE:

Test Substance	Gastric Bioaccessibility- 2 hours (mg/l)	surface area (m2/g)	release per surface (mg/m2)	Gastric Bioaccessibility- 2 hours as % released of total content
Lead	58.8	2.93	10	9.5
Tellurium	38.6	2.93	6.6	5.3
Tungsten	0.446	2.93	0.076	0.34

Applicant's summary and conclusion

Conclusions:

HH Assessment being PbO as the main driver

a. Acute Classification assessment – Oral route
The ATE of the mixture (ATEmix) is determined by calculation from the ATE values for all relevant ingredients according to the following formula for Oral, Dermal or Inhalation Toxicity.
By solving the equation, an ATEmix of 15787 (mg/Kg bw) is obtained. This value is higher than the threshold of 2000 (mg/Kg bw), thus, according to the Acute Oral classification criteria, this classification does not apply due to PbO content.

b. Acute Classification assessment – Inhalation route
By solving the equation, an ATEmix of 26,81 (mg/l) is obtained. This value is higher than the threshold of 5 (mg/l) set by CLP Regulation, thus, according to the Acute INH classification criteria, this classification does not apply due to PbO content.

c. Carcinogenicity assessment
The effective concentation (Bioaccessible concentration-INH route/GCL) is higher (3.167%) than the Generic Concentration Limit of 1% set by the CLP Regulation triggering carcinogenicity Cat.2, being the lead monoxide the main driver. Therefore according to the CLP classification criteria, this classification shall apply.

d. Reprotox assessment
The effective concentation (Bioaccessible concentration/GCL) is higher (10.56%) than the Generic Concentration Limit of 0.3% set by the CLP Regulation triggering toxicity for the reproduction Cat.1A, being the lead monoxide the main driver. Therefore according to the CLP classification criteria, this classification shall apply.
(same would apply for effects on or via lactation)

e. STOT Repeated exposure assessment
The effective concentation (Bioaccessible concentration/GCL) is higher (6.334%) than the Specific Concentration Limit of 0.5% set by the self-classification included in the EU-REACH Registration Dossier triggering toxicity. Therefore according to the CLP classification criteria, this classification shall apply.


HH Assessment being PbO as the main driver

a. Skin Sensitisation assessment
The effective concentation (Bioaccessible concentration/GCL) is higher (2,43%) than the Generic Concentration Limit of 1% set by the CLP Regulation triggering toxicity as Skin Sensitiser Cat.1B, being the tellurium dioxide the main driver. Therefore according to the CLP classification criteria, this classification shall apply.

Executive summary:

HH Assessment being PbO as the main driver

Acute Classification assessment – Oral route

HH Assessment applying the most conservative approach for deriving hazard classification: Application of the CLP mixture rules.

According to section 3.1.3.6.2, In order to ensure that classification of the mixture is accurate, and that the calculation need only be performed once for all systems, sectors, and categories, the acute toxicity estimate (ATE) of ingredients shall be considered as follows:

3. include ingredients with a known acute toxicity, which fall into any of the acute hazard categories shown in Table 3.1.1; (our case);


4. ignore ingredients that are presumed not acutely toxic (e.g., water, sugar);


5. ignore components if the data available are from a limit dose test (at the upper threshold for Category 4 for the appropriate route of exposure as provided in Table 3.1.1) and do not show acute toxicity.

The ATE of the mixture (ATE_mix) is determined by calculation from the ATE values for all relevant ingredients according to the following formula for Oral, Dermal or Inhalation Toxicity.

By solving the equation, an ATEmix of 15787 (mg/Kg bw) is obtained. This value is higher than the threshold of 2000 (mg/Kg bw), thus, according to the Acute Oral classification criteria, this classification does not apply due to PbO content.

Acute Classification assessment – Inhalation route PbO+TeO2

By solving the equation, an ATEmix of 26,81 (mg/l) is obtained. This value is higher than the threshold of 5 (mg/l) set by CLP Regulation, thus, according to the Acute INH classification criteria, this classification does not apply due to PbO content.

Carcinogenicity assessment

HH Assessment applying the most conservative approach for deriving hazard classification: Application of the CLP mixture rules.

Carcinogen means a substance or a mixture of substances which induce cancer or increase its incidence.

According to section 3.6.3.1.1, the mixture will be classified as a carcinogen when at least one ingredient has been classified as a Category 1A, Category 1B or Category 2 carcinogen and is present at or above the appropriate generic concentration limit as shown in Table 3.6.2 for Category 1A, Category 1B and Category 2 respectively.

The effective concentation (Bioaccessible concentration-INH route/GCL) is higher (3.167%) than the Generic Concentration Limit of 1% set by the CLP Regulation triggering carcinogenicity Cat.2, being the lead monoxide the main driver. Therefore according to the CLP classification criteria, this classification shall apply.

 

 

 

 

Reprotox assessment

HH Assessment applying the most conservative approach for deriving hazard classification: Application of the CLP mixture rules.

According to section 3.7.3.1.1 of CLP Regulation, the mixture shall be classified as a reproductive toxicant when at least one ingredient has been classified as a Category 1A, Category 1B or Category 2 reproductive toxicant and is present at or above the appropriate generic concentration limit as shown in Table 3.7.2 for Category 1A, Category 1B and Category 2 respectively.

The effective concentation (Bioaccessible concentration/GCL) is higher (10.56%) than the Generic Concentration Limit of 0.3% set by the CLP Regulation triggering toxicity for the reproduction Cat.1A, being the lead monoxide the main driver. Therefore according to the CLP classification criteria, this classification shall apply.

(same would apply for effects on or via lactation)

 

STOT Repeated exposure assessment

HH Assessment applying the most conservative approach for deriving hazard classification: Application of the CLP mixture rules.

According to section 3.9.3.4.2 of CLP Regulation, where there is no reliable evidence or test data for the specific mixture itself, and the bridging principles cannot be used to enable classification, then classification of the mixture is based on the classification of the ingredient substances.

In this case, the mixture shall be classified as a specific target organ toxicant (specific organ specified), following single exposure, repeat exposure, or both when at least one ingredient has been classified as a Category 1 or Category 2 specific target organ toxicant and is present at or above the appropriate generic concentration limit as laid out in Table 3.9.4 for Category 1 and 2 respectively, unless the target substance has been assigned with a SCL, that is the case of PbO with a SCL for STOT-RE-1 ≥ 0,5%.

The effective concentation (Bioaccessible concentration/GCL) is higher (6.334%) than the Specific Concentration Limit of 0.5% set by the self-classification included in the EU-REACH Registration Dossier triggering toxicity. Therefore according to the CLP classification criteria, this classification shall apply.

 

 

 

 

HH Assessment >>>> being TeO2 as the main driver

Skin Sensitisation assessment

HH Assessment applying the most conservative approach for deriving hazard classification: Application of the CLP mixture rules.

According to CLP Regulation section 3.4.3.3.1, a mixture shall be classified as a respiratory or skin sensitiser when at least one ingredient has been classified as a respiratory or skin sensitiser and is present at or above the appropriate generic concentration limit as shown in Table 3.4.5 for solid/ liquid and gas respectively.

The effective concentation (Bioaccessible concentration/GCL) is higher (2,43%) than the Generic Concentration Limit of 1% set by the CLP Regulation triggering toxicity as Skin Sensitiser Cat.1B, being the tellurium dioxide the main driver. Therefore according to the CLP classification criteria, this classification shall apply.