Vanadium carbide nitride (V(C,N))

Endpoint summary

Description of key information

Key studies demonstrate a lack of irritation/corrosion potential: 
Data are read-across from a structural analogue, i.e. vanadium metal powder, based on inertness and similar solubility or lack thereof.
An in vitro skin irritation study (EpiSkinTM) was performed with vanadium metal powder (Heppenheimer, 2010), and results indicate that it is not irritant to skin. 
An acute eye irritation / corrosion test according to OECD 405 (Leuschner, 2010) was performed with vanadium metal powder, and results indicate that it is not irritant to eyes. 
Based on read-across (see discussion), it is assumed that vanadium carbide nitride does also not cause respiratory irritation. 

Key value for chemical safety assessment

Skin irritation / corrosion

Link to relevant study records

Reference

Endpoint:

skin irritation: in vitro / ex vivo

Type of information:

migrated information: read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Study period:

2010-03-03 to 2010-03-08

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

EU Method B.46 (In Vitro Skin Irritation: Reconstructed Human Epidermis Model Test)

Version / remarks:

2008

Deviations:

no

Qualifier:

according to guideline

Guideline:

other: ECVAM international validation study on in vitro tests for acute skin irritation (Altern Lab Anim. 2007 Dec; 35 (6):559-601)

Version / remarks:

2007

Deviations:

no

Qualifier:

according to guideline

Guideline:

other: OECD Guideline for the Testing of Chemicals; Draft proposal for a new guideline, in vitro skin irritation: Reconstructed Human Epidermis (RhE) Test method, 11 December 2009, Vers. 4.

Version / remarks:

2009-12-11

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Remarks:

signed 2009-03-30

Specific details on test material used for the study:

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: at room temperature, protected from moisture

Test system:

human skin model

Source species:

human

Cell type:

other: normal, human-derived epidermal keratinocytes

Cell source:

other: adult donor

Source strain:

not specified

Details on animal used as source of test system:

not applicable

Justification for test system used:

not specified

Vehicle:

water

Details on test system:

RECONSTRUCTED HUMAN EPIDERMIS (RHE) TISSUE
- Model used: EpiSkin TM skin model (purchased from Skinethic Laboratories)
- Tissue lot number: 10-EKIN-007
- Expiration date: 2010-03-08
- Shipping date: 2010-03-01
- Delivery date: 2010-03-02
- Date of initiation of testing: 2010-03-03

TEMPERATURE USED FOR TEST SYSTEM
- Temperature used during treatment / exposure: 37 ± 1.5 °C
- Temperature of post-treatment incubation: 37 ± 1.5 °C

REMOVAL OF TEST MATERIAL AND CONTROLS
- after the end of the treatment interval the inserts were removed from the 12-well plate.
- tissues were rinsed with PBS to remove any residual test material.
- excess PBS was removed by gently shaking the inserts and blotting the bottom with blotting paper.

MTT DYE USED TO MEASURE TISSUE VIABILITY AFTER TREATMENT / EXPOSURE
- MTT concentration: 300 µg/mL
- Incubation time with MTT: 3 hours
- Extraction of formazan: After the incubation period, the MTT solution was aspirated from the wells and the wells were rinsed with PBS. Tissue samples were cut out of the inserts and transferred into vials. Tissue samples were immersed into extractant solution by pipetting isopropanol into each vial. The tissue samples were completely covered by isopropanol. The vials were sealed to inhibit isopropanol evaporation. The formazan salt was extracted for approx. 70 hours in the refrigerator.
Per each tissue sample 2 × 200 µL aliquots of the formazan blue solution were transferred into a 96-well flat bottom microtiter plate and the optical density was determined with a spectrophotometer. Mean values were calculated from the 2 wells per tissue sample.
- Spectrophotometer: Versamax® Molecular Devices
- Wavelength: 570 nm without reference filter

TEST FOR DIRECT MTT REDUCTION
To test for the ability of the test item to directly reduce MTT approximately 15 mg of the test item were added to 1 mL of MTT solution and the mixture was incubated in the dark at room temperature for 60 minutes. Untreated MTT medium was used as control. If the MTT solution colour turned blue/purple, the test item was presumed to have reduced the MTT.

FUNCTIONAL MODEL CONDITIONS WITH REFERENCE TO HISTORICAL DATA
- Viability: mean optical density of the negative control was 0.857 (historical data range: 0.7 - 1.6)
- Barrier function: IC50 = 1.9 mg/mL (specification ≥ 1.5 mg/mL)
- Morphology: histology scoring = 23.0 (specification ≥ 19.5); well.differentiated epidermis consisting of a basal layer, several spinous and granular layers and a thick stratum corneum.
- Contamination: absence of bacteria, fungus and mycoplasma as well as absence of HIV1 and 2 antibodies, hepatitis C antibodies, and hepatitis B antigen
Please also refer to the field "Attached background material" below.

PREDICTION MODEL / DECISION CRITERIA
The mean optical density of the three negative control tissues was calculated. This value corresponds to 100% tissue viability in the current test. For each individual tissue treated with the test item or the positive control the individual relative tissue viability is calculated according to the following formula: relative viability(%) = (OD test item/ OD negative control) x 100
For the test item and the positive control the mean relative viability ± standard deviation of the three individual tissues are calculated and used for classification according to the following prediction model: for the current test, an irritation potential of a test item according to CLP classification category 2 is predicted if the mean relative tissue viability of three individual tissues is less or equal to 50% of the negative control.

Control samples:

yes, concurrent negative control

yes, concurrent positive control

Amount/concentration applied:

TEST MATERIAL
- Amount(s) applied (volume or weight with unit): approx. 15 mg of the test item were applied to each of triplicate tissues.

VEHICLE
- Amount(s) applied (volume or weight with unit): 15 µL of deionised water

NEGATIVE CONTROL
- Amount(s) applied (volume or weight): 15 µL

POSITIVE CONTROL
- Amount(s) applied (volume or weight): 15 µL

Duration of treatment / exposure:

15 ± 1 min

Duration of post-treatment incubation (if applicable):

42 ± 1 hours

Number of replicates:

Test item: triplicates
Negative control: triplicates
Positive control: triplicates

Irritation / corrosion parameter:

% tissue viability

Value:

90.8

Vehicle controls validity:

not examined

Negative controls validity:

valid

Positive controls validity:

valid

Remarks on result:

no indication of irritation

Other effects / acceptance of results:

- OTHER EFFECTS:
- Direct-MTT reduction: optical evaluation of the MTT-reducing capacity of the test item after 1 hour incubation with MTT-reagent did not show blue colour, i.e. the tet item was not persumed to reduce the MTT.

ACCEPTANCE OF RESULTS:
- Acceptance criteria met for negative control: after treatment with the negative control the absorbance values (0.878, 0.819, and 0.873, respectively) were well above the required acceptability criterion of mean optical density (0.6 ≤ OD ≤ 1.5) for the 15 minutes treatment interval.
- Acceptance criteria met for positive control: treatment with the positive control induced a decrease in the relative absorbance as compared to the negative control to 27.4% (acceptability criterion: positive control is ≤ 40 %).
- Acceptance criteria met for variability between replicate measurements: standard deviations between the % variabilities of the test item, the positive and negative controls were below 6% (threshold of the "OECD Guideline for the Testing of Chemicals, Draft Proposal for a New Guideline, In Vitro Skin Irritation": 18%).

Results after treatment with vanadium (metal)

 

Dose group	Treatment Interval	Absorbance 570 nm Tissue 1	Absor-bance 570 nm Tissue 2	Absorbance 570 nm Tissue 3	Mean Absorbance of 3 Tissues	Absorbance [%] Tissue 1, 2 + 3	Rel. Standard Deviation	Rel. Absorbance [% of Negative Control]
Negative Control	15 min	0.878	0.819	0.873	0.857	102.5 95.6 101.9	3.8	100.0
Positive Control	15 min	0.293	0.209	0.203	0.235	34.2 24.4 23.7	5.9	27.4
Vanadium (metal)	15 min	0.752	0.786	0.797	0.778	91.7 93.0 83.6	2.7	90.8

Historical data:

Positive Control		Negative Control
Number of Studies	73	Number of Studies	73
Period	July 2007 - March 2010	Period	July 2007 - March 2010
Mean Viability	16.5 %	Mean OD	1.081
Standard Deviation	11.0%	Standard Deviation	0.262
Range of Viabilities	3% - 36%	Range of ODs	0.7 – 1.6*

* The upper OD value is outside of the range of 0.6 - 1.5 recommended by the OECD guideline. Nevertheless since the OD value is only slightly above the required range, the historical data can still be considered as valid.

Interpretation of results:

not irritating

Conclusions:

The test item is not irritating to the skin.
According to the Regulation (EC) No 1272/2008 and subsequent regulations, the test item is not irritating to the skin.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not irritating)

Eye irritation

Link to relevant study records

Reference

Endpoint:

eye irritation, other

Remarks:

in vivo study

Type of information:

migrated information: read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Study period:

2010-05-18 to 2010-05-30

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 405 (Acute Eye Irritation / Corrosion)

Version / remarks:

2002-04-24

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Remarks:

signed 2009-11-12

Species:

rabbit

Strain:

Himalayan

Details on test animals or tissues and environmental conditions:

TEST ANIMALS
- Source: LPT Laboratory of Pharmacology and Toxicology GmbH & Co. KG, Branch Löhndorf, 24601 Löhndorf/Post Wankendorf, Germany
- Age at study initiation: Approx. 4 - 5 months
- Weight at study initiation: Animal 1: 2.4 kg; Animal 2: 2.0 kg; Animal 3: 2.5 kg
- Housing: For 8 hours following test item application, the animals were kept singly in restrainers which allowed free movement of the head but prevented a complete body turn, wiping of the eyes with the paws and excluded irritation of the eye by excrements and urine. During the acclimatisation period and after the 8-hour period in restrainers, the animals were kept singly in cages with dimensions of 380 mm x 425 mm x 600 mm (manufacturer: Dipl.Ing. W. EHRET GmbH, 16352 Schönwalde, Germany).
- Diet (ad libitum): Commercial diet, ssniff7 K-H V2333 (ssniff Spezialdiäten GmbH, 59494 Soest, Germany)
- Water (ad libitum before and after the exposure period): Tap water
- Acclimation period: At least 20 adaptation days

ENVIRONMENTAL CONDITIONS
- Temperature: 20 °C +/- 3 °C (maximum range)
- Relative humidity: 30% - 70% (maximum range; aim was 50% - 60%)
- Photoperiod (hrs dark / hrs light): 12/12
No further information on the test animals was stated.

Vehicle:

unchanged (no vehicle)

Controls:

no

Amount / concentration applied:

TEST MATERIAL
- Amount(s) applied (volume or weight with unit): 100 mg of the test item were administered into one eye each of three animals. The test item was placed into the conjunctival sac of the right eye of each ani¬mal after gently pulling the lower lid away from the eyeball. The lids were then gently held together for about one second in order to prevent loss of the material. The left eye, which remained untreated, served as a control.
No further information on the amount/concentration applied was stated.

Duration of treatment / exposure:

1 hour (One hour after application the eyes were rinsed.)

Observation period (in vivo):

1, 24, 48 and 72 hours after the administration

Number of animals or in vitro replicates:

3 male rabbits

Details on study design:

It is explicitly note and in accordance with the guideline used, that the test was performed initially using one animal. As no corrosive or severe irritant effects were observed in this animal, 2 further animals were employed 24 hours after start of the initial test.

REMOVAL OF TEST SUBSTANCE
- Washing (if done): The eyes were rinsed with portions of 20 mL 0.9% aqueous NaCl solution, each.
- Time after start of exposure: 1 hour after administration

SCORING SYSTEM: Draize scoring system

TOOL USED TO ASSESS SCORE: The eyes were examined ophthalmoscopically with a slit lamp prior to the administration and 1, 24, 48 and 72 hours after the administration. The eye reactions were observed and registered.
24 hours after administration, fluorescein (Fluorescein SE Thilo drops (ALCON PHARMA GmbH, 79108 Freiburg, Germany) was applied to the eyes before being examined to aid evaluation of the cornea for possible lesions.

OTHER OBSERVATIONS: Any further lesions not covered by the scoring system were recorded. Body weight of all animals was measured at the beginning of the study and at the end of the study. Behaviour and food consumption were monitored.
No further information on the study design was stated.

Irritation parameter:

cornea opacity score

Basis:

mean

Remarks:

animal #1

Time point:

other: 24,48, and 72 hours

Score:

0

Max. score:

0

Irritation parameter:

iris score

Basis:

mean

Remarks:

animal #1

Time point:

other: 24, 48, and 72 hours

Score:

0

Max. score:

0

Irritation parameter:

conjunctivae score

Basis:

mean

Remarks:

animal #1

Time point:

other: 24, 48, and 72 hours

Score:

0

Max. score:

0

Irritation parameter:

chemosis score

Basis:

mean

Remarks:

animal #1

Time point:

other: 24, 48, and 72 hours

Score:

0

Max. score:

0

Irritation parameter:

cornea opacity score

Basis:

mean

Remarks:

animal #2

Time point:

other: 24, 48, and 72 hours

Score:

0

Max. score:

0

Irritation parameter:

iris score

Basis:

mean

Remarks:

animal #2

Time point:

other: 24, 48, and 72 hours

Score:

0

Max. score:

0

Irritation parameter:

conjunctivae score

Basis:

mean

Remarks:

animal #2

Time point:

other: 24, 48, and 72 hours

Score:

0

Max. score:

0

Irritation parameter:

chemosis score

Basis:

mean

Remarks:

animal #2

Time point:

other: 24, 48, and 72 hours

Score:

0

Max. score:

0

Irritation parameter:

cornea opacity score

Basis:

mean

Remarks:

animal #3

Time point:

other: 24, 48, and 72 hours

Score:

0

Max. score:

0

Irritation parameter:

iris score

Basis:

mean

Remarks:

animal #3

Time point:

other: 24, 48, and 72 hours

Score:

0

Max. score:

0

Irritation parameter:

conjunctivae score

Basis:

mean

Remarks:

animal #3

Time point:

other: 24, 48, and 72 hours

Score:

0.33

Max. score:

1

Reversibility:

fully reversible within: 48 hours

Irritation parameter:

chemosis score

Basis:

mean

Remarks:

animal #3

Time point:

other: 24, 48, and 72 hours

Score:

0

Max. score:

0

Irritant / corrosive response data:

Conjunctival redness (Grade 1: Some blood vessels hyperaemic (injected)) was observed in all animals 1 hour after instillation, in animal no. 3 until 24 hours after instillation. The mean score per animal, following grading at 24, 48 and 72 h after installation of the test material was calculated < 2. The effect was fully reversible within 48 h after application of the test material.
In addition, secretion was observed in animal no. one 1 hour after instillation.
The corneae and the irises were not affected by instillation of the test item.
The fluorescein test performed 24 hours after instillation did not reveal any changes.

Other effects:

There were no systemic intolerance reactions.

Interpretation of results:

not irritating

Remarks:

Migrated information Criteria used for interpretation of results: EU

Conclusions:

According to the EC-Commission directive 67/548/EEC and its subsequent amendments on the approximation of the laws, regulations and administrative provision relating to the classification, packaging and labelling of dangerous substances and the results obtained under the present test conditions vanadium (metal) is non-irritating to eyes, hence, no labelling is required.
Also, according to the EC Regulation 1272/2008 and subsequent regulations, vanadium (metal) is non-irritating to eyes; no classification and labelling of the substance is necessary.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not irritating)

Respiratory irritation

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not irritating)

Additional information

Speciation:

Upon dissolution, vanadium substances transform inartificial body fluids, including PBS, sweat, gastric juice and lung fluid, predominantlyto the pentavalent form,exceptin artificial lysosomal fluid; here, even pentavalent forms are converted almost completely totetravalent species already after a short period of time (for more information on in vitro bioaccessibility testing,please refer IUCLID section 7). Thus, it can be assumed that vanadium speciation in body fluids is controlled by the conditions of the respective medium but not by the vanadium source.

Read across concept:

The toxicity of vanadium carbide nitride may reasonably be considered to be determined by the bioavailability of vanadium. As a first surrogate for bioavailability, the water solubility of a test substance may be used. Vanadium metal and vanadium carbide nitride are poorly soluble in water (9.6 µg/L at 20°C/pH 6.8) and thus, vanadium metal and vanadium carbide nitride can be considered biologically and toxicologically inert. Thus,read-acrossof data between vanadium metal and vanadium carbide nitride is fully justified.

Justification for selection of skin irritation / corrosion endpoint:
One reliable study conducted with vanadium is read-across to address this endpoint. Vanadium is not considered to be irritating to the skin. Consequently, vanadium carbide nitride is also not considered to be irritating to the skin.

Justification for selection of eye irritation endpoint:
One reliable study conducted with vanadium is read-across to address this endpoint. Vanadium is not considered to be irritating to the eyes. Consequently, vanadium carbide nitride is also not considered to be irritating to the eyes.

Justification for classification or non-classification

Skin and eye irritation:

Vanadium carbide nitride does not possess an irritation potential and does not require classification as skin or eye irritant according to Directive 67/548/EEC and Regulation (EC) 1272/2008.

Respiratory irritation:

Vanadium carbide nitride is only produced in briquette form. Based on the technical properties of a representative test material, the conduct of an acute inhalation toxicity test is neither technically feasible nor scientifically relevant for this type of compound. Due to the particle size, the low mobility and the negligible volatility, vanadium carbide nitride in briquette form can safely be assumed to have avery low potential for human inhalation hazard during handling or application. In addition, vanadium carbide nitride is poorly water soluble (< 1 mg/L at 20°C/6.8 pH) indicating inertness and a corresponding lack of potential to become bioavailable. Furthermore, pH-related effects do not need to be assumed upon contact with respiratory tract epithelia, and any lung overload associated with inert particles can be excluded. In sum, it is assumed that vanadium carbide nitride does not cause respiratory tract irritation.