Zirconium tetrabutanolate

Endpoint summary

Key value for chemical safety assessment

Skin irritation / corrosion

Link to relevant study records

Reference

Reference 1

Endpoint:

skin corrosion: in vitro / ex vivo

Type of information:

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

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Justification for type of information:

The read-across source zirconium tetrapropanolate and the target substance belong to simple alkoxides of metals of the same group (titanium and zirconium). Due to rapid hydrolysis, the intrinsic properties/toxicities lie in the organic part of the hydrolysis products. The main organic hydrolysis product is 1-propanol and therefore the properties are considered similar.

Reason / purpose for cross-reference:

read-across source

Qualifier:

according to guideline

Guideline:

OECD Guideline 439 (In Vitro Skin Irritation: Reconstructed Human Epidermis Test Method)

GLP compliance:

yes (incl. QA statement)

Irritation / corrosion parameter:

% tissue viability

Run / experiment:

3

Value:

ca. 9.27

Vehicle controls validity:

not applicable

Negative controls validity:

valid

Positive controls validity:

valid

Remarks on result:

positive indication of irritation

Interpretation of results:

Category 2 (irritant) based on GHS criteria

Executive summary:

The target substance is irritating to skin, read-across from studies tested on structural analogue zirconium tetrapropanolate.

Reference 2

Endpoint:

skin irritation: in vitro / ex vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2017 July to 2017 September

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 439 (In Vitro Skin Irritation: Reconstructed Human Epidermis Test Method)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Specific details on test material used for the study:

SOURCE OF TEST MATERIAL
- Supplier: Borica Co., Ltd.
- Lot number: 000577Z
- Expiration date of the lot/batch: 2018-Jul-06
- CAS number: 23519-77-9

Test system:

human skin model

Source species:

human

Cell type:

non-transformed keratinocytes

Vehicle:

unchanged (no vehicle)

Details on test system:

EpiDerm (EPI-200-MatTek Corporation) was used as reconstructed human epidermal model. It consisted of normal human-derived epidermal keratinocytes which have been cultured to form a multi-layered highly differentiated model of the human epidermis. It consisted of organized basal, spinous and granular layers and a multi-layered stratum corneum containing intercellular lamellar lipid layers arranged in patterns analogous to those found in vivo.

RECONSTRUCTED HUMAN EPIDERMIS (RHE) TISSUE
- Model used: EpiDerm™ (EPI-200) RECONSTRUCTED HUMAN EPIDERMIS
- Tissue batch number(s): 25837
- Date of initiation of testing: 2017-Jul-13


PREDICTION MODEL / DECISION CRITERIA (choose relevant statement)
- The test substance is considered to be corrosive to skin if [complete, e.g. the viability after 3 minutes exposure is less than 50%, or if the viability after 3 minutes exposure is greater than or equal to 50 % and the viability after 1 hour exposure is less than 15%.]
- The test substance is considered to be non-corrosive to skin if [complete, e.g. the viability after 3 minutes exposure is greater than or equal to 50% and the viability after 1 hour exposure is greater than or equal to 15%.]

Control samples:

yes, concurrent negative control

yes, concurrent positive control

Amount/concentration applied:

TEST MATERIAL
- Amount(s) applied (volume or weight with unit): 30 microliter neat test material


VEHICLE
- Not used


NEGATIVE CONTROL
- Amount(s) applied (volume or weight): 30 microliter Sterile Dulbecco's phosphate buffered saline (DPBS)
- Concentration (if solution): neat

POSITIVE CONTROL
- Amount(s) applied (volume or weight): 30 microliter Sodium dodecyl sulphate (SDS)
- Concentration (if solution): 5%

Duration of treatment / exposure:

60 +/- 1 minutes (25 minutes at room temperature and 35 minutes at 37°C, 5% CO2, >=95% RH)

Duration of post-treatment incubation (if applicable):

42 +/- 4 h hours post-treatment incubation.

Number of replicates:

3 repliecate per run.

Vehicle:

unchanged (no vehicle)

Irritation / corrosion parameter:

% tissue viability

Run / experiment:

3

Value:

ca. 9.27

Vehicle controls validity:

not applicable

Negative controls validity:

valid

Positive controls validity:

valid

Remarks on result:

positive indication of irritation

Table 3. Mean and SD of cell viability measurements and of viability precentages after 60 min (+/- 1 min) of application and 42 h (+/-4 h) post-incubation.

Name	Code	Mean of OD	SD of OD	Mean of viability (%)	SD of viability (%)	CV (%)	Classification
DPBS	NC	1.322	0.150	100.0	11.34	11.34	Non-irritant
SDS 5%	PC	0.054	0.014	4.085	1.07	26.26	Irritant
Test item	TA2	0.123	0.022	9.266	1.67	18.08	Irritant

Predition model: test items that reduce the viability to 50% or below are irritant (I); test items with a percentage viability above 50% are considered to be non-irritant (NI).

Notes:

NC: Negative control

PC: Positive control

TA: Zirconium tetrapropanolate

Interpretation of results:

Category 2 (irritant) based on GHS criteria

Conclusions:

A test item is considered to be an irritant (I) to skin in accordance with UN GHS Category 2 or EU R38 if the skin model viability after exposure and post-treatment incubation is ≤50%.
A test item may be considered as a non-irritant (NI) if the skin model viability after exposure and post-treatment incubation is > 50%.
The percentage of viability obtained with the test item Zirconium tetrapropanolate was 9.266%, therefore it was considered as irritant to the skin.

Executive summary:

The skin irritation potential of Zirconium tetrapropanolate was assessed in vitro according to OECD Test Guideline 439: In Vitro Skin irritation: Reconstructed Human Epidermis Test Method.

After 60 +/- 1 min exposure on the surface of the EpiDerm™ reconstructed human epidermis and a 42 +/- 4 h post-exposure incubation time, viability of the tissues was assessed and compared to the negative control. The percentage of viability obtained was 9.266% and therefore:

Zirconium tetrapropanolate

was classified as Irritant to the skin.

Endpoint conclusion

Endpoint conclusion:

adverse effect observed (irritating)

Eye irritation

Link to relevant study records

Reference

Reference 1

Endpoint:

eye irritation: in vitro / ex vivo

Type of information:

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

Adequacy of study:

weight of evidence

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Justification for type of information:

The read-across source zirconium tetrapropanolate and the target substance belong to simple alkoxides of metals of the same group (titanium and zirconium). Due to rapid hydrolysis, the intrinsic properties/toxicities lie in the organic part of the hydrolysis products. The main organic hydrolysis product is 1-propanol and therefore the properties are considered similar.

Reason / purpose for cross-reference:

read-across source

Qualifier:

according to guideline

Guideline:

OECD Guideline 492 (Reconstructed Human Cornea-like Epithelium (RhCE) Test Method for Identifying Chemicals Not Requiring Classification and Labelling for Eye Irritation or Serious Eye Damage)

GLP compliance:

yes (incl. QA statement)

Irritation parameter:

other: tissue viability

Run / experiment:

1 run, 3 replicates per run

Value:

ca. 15.27

Vehicle controls validity:

not applicable

Negative controls validity:

valid

Positive controls validity:

valid

Remarks on result:

positive indication of irritation

Interpretation of results:

Category 2 (irritating to eyes) based on GHS criteria

Executive summary:

The target substance is irritating to eyes, read-across from studies tested on structural analogue zirconium tetrapropanolate.

Reference 2

Endpoint:

eye irritation: in vitro / ex vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2017 July to 2017 September

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 492 (Reconstructed Human Cornea-like Epithelium (RhCE) Test Method for Identifying Chemicals Not Requiring Classification and Labelling for Eye Irritation or Serious Eye Damage)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Specific details on test material used for the study:

SOURCE OF TEST MATERIAL
- Supplier: Borica Co., Ltd.
- Lot number: 000577Z
- Expiration date of the lot/batch: 2018-Jul-06
- CAS number: 23519-77-9

Species:

human

Vehicle:

unchanged (no vehicle)

Controls:

yes, concurrent positive control

yes, concurrent negative control

Amount / concentration applied:

TEST MATERIAL
- Amount(s) applied (volume or weight with unit): 50 microliter
- Concentration (if solution): neat

VEHICLE
- Not used

Duration of treatment / exposure:

30 minutes +/- 2 min

Duration of post- treatment incubation (in vitro):

12 +/- 2 min post-treatment immersion and 2 hours +/- 15 min post-treatment incubation.

Number of animals or in vitro replicates:

3 replicates per run.

Details on study design:

- Details of the test procedure used
Prior to the study, the required compatibility checks confirmed that the test item interfered with MTT and therefore additional freeze killed negative controls (NC-FK) and freeze killed test item controls (TA-FK) were included in the assay to determine the background level of interference (manifesting as altered viability) produced by the test item. The level of viability measured in the interference controls was subtracted from the standard test viability value to give an adjusted final viability. No water colouration was observed and therefore colorant control was not required.

After pre-wetting tissues with 20 microliter PBS (Sterile Dulbecco’s phosphate buffered saline) for 30 +/- 2 min, single topical application of 50 microliter of neat test item or of reference items to the surface of the EpiOcular™ models for 30 +/- 2 min, followed by a 12 +/- 2 min post-treatment immersion, and 2 hr +/- 15 min post-treatment incubation, prior to the MTT endpoint; three tissues per condition (n = 3).


- RhCE tissue construct used, including batch number
EpiOcular™ EIT (OCL-200) Reconstructed Human Ocular Epithelium
Supplier: MatTek Corporation
Keratinocyte Strain: 4F1188
Lot number: 23799
Description of the RhCE tissue: The EpiOcular™ tissue model (OCL200-MatTek Corporation) is composed of stratified human keratinocytes in a three-dimensional structure, reflecting the morphology and function of the human corneal epithelium found in vivo.


- MTT test conditions
Spectrometer: BMG LabTech FluoStar Optima
Wavelength for O.D. measurements: 570 nm


- Positive and negative control means and acceptance ranges based on historical data
1. Mean OD570 of the negative control (treated with sterile water) tissues is > 0.8 and < 2.5.
2. Mean of the positive control relative percentage viability is below 50% of negative control viability after 30 +/- 2 minutes exposure.


- Acceptable variability between tissue replicates for positive, negative controls and test items
The SD between three tissues replicates should not exceed 18% in the same run (for negative and positive control tissues and tissues of test items).

Irritation parameter:

other: Tissue viability

Run / experiment:

1 run, 3 replicates per run

Value:

ca. 15.27

Vehicle controls validity:

not applicable

Negative controls validity:

valid

Positive controls validity:

valid

Remarks on result:

positive indication of irritation

Table 3. Mean and SD of viability measurements and of viability percentages after 30 +/- 2 min of application and 2 h +/- 15 min post-incubation of test and reference items.

Consition	Mean of OD	SD of OD	mean of viability %	SD of viability (%)	CV %	Classification
NC	1.657	0.016	100.00	0.938	0.938	Non-irritant
PC	0.522	0.115	31.479	6.964	22.122	Irritant
TA2	0.253	0.008	15.277	0.481	3.150	Irritant

Note:

NC: Negative control (sterile H2O)

PC: neat methyl acetate

TA2: Zirconium tetrapropanolate

Interpretation of results:

Category 2 (irritating to eyes) based on GHS criteria

Conclusions:

A Test item is considered to be irritant to the eye (i.e. would require labelling as either GHS 1 or 2) if they eye model viability after exposure and post-treatment incubation is ≤ 60%.
A test item is considered as a non-irritant to the eye (i.e. would not require a warning label in the European chemical classification systems) if the eye model viability after exposure and post-treatment incubation is > 60%.
The current assay is not intended to differentiate between GHS class 1 and GHS class 2 or R36 and R41 (degree of stromal damage).
The percentage of viability obtained with test item Zirconium tetrapropanolate was 5.602%, therefore it is considered as Irritant to the eye.

Executive summary:

The eye irritation potential of Zirconium tetrapropanolate was assessed in vitro according to OECD Test Guideline 492 (Reconstructed human Cornea-like Epithelium (RhCE) test method for identifying chemicals not requiring classification and labeling for eye irritation or serious eye damage).

After a 30 +/-2 minute exposure on the surface of EpiOcular™ reconstructed ocular epithelium and 2 h +/- 15 mins post-incubation time, the viability of the tissues was assessed and compared to a negative control. The percentage viability was 5.602% and therefore:

Zirconium tetrapropanolate

was classified as Irritant to the human eye.

Endpoint conclusion

Endpoint conclusion:

adverse effect observed (irreversible damage)

Respiratory irritation

Endpoint conclusion

Endpoint conclusion:

no study available

Additional information

No studies were conducted on the target substance zirconium tetrabutanolate. The studies of structure analogue, zirconium tetrapropanolate were used for read-across.

Studies using alternative in vitro methods – OECD 439, reconstructed human epidermis, and OECD 492, reconstructed human cornea-like epithelium. The target substance was found irritating in the two tests.

 

As the target substance hydrolyses rapidly (half-life < 5 minutes) the intrinsic properties are related to hydrolysis products – 1 -butanol. The C&L database of the registered substance indicated serious eye damage category 1 but not irritating to skin.

For safety consideration, it is safe to treat the target sbustacne as eye damage category 1 and irritating to skin, according to the in vitrol alternative test.

 

Based on above findings, the target substance is therefore considered irritating to skin category 2 and corrosive to eyes category 1 according to CLP regulations.

Justification for classification or non-classification

Based on results of alternative in vitro methods, OECD 439 and OECD 492, tested on the target substance, the results indicated irritating to skin and eyes.

The hydrolysis products, 1 -butanol, has also been found damage to eyes category 1, Irritant to skin category 2, specific target organ toxicty - respiratory irritation and CNS effect category 3.

Therefore, the target substance is classified as

Skin irritating Category 2, H315

Eye damage Category 1, H318

Specific target organ toxicity category 3, H335

Specific target organ toxicity Category 3, H336

according to CLP regulation.