Borate(1-), bis[ethanedioato(2-)-.kappa.O1,.kappa.O2]-, potassium (1:1), (T-4)-

Endpoint summary

Description of key information

The potential corrosive effect of KBOB was studied with EpiDerm tissue, in compliance with OECD TG 431. According to study results, the test item was classified as non-corrosive. 
The potential skin irritation effects were evaluated based on the acute skin irritation study of lithium bis(oxalato)borate (LiBOB), a structurally similar substance. The test was performed in New Zealand White rabbits according to OECD guideline 404 and EU method B.4. The irritation effect of the test item was evaluated according to the Draize method. According to study results lithium bis(oxalato)borate is non irritating to the intact skin of New Zealand white rabbits. Consequently, also potassium bis(oxalato)borate can be regarded as non-irritating to skin. 
They eye corrosion potential of KBOB was investigated in the in vitro bovine corneal opacity and permeability assay according to OECD Technical Guideline 437 (Bovine Corneal Opacity and Permeability Test Method for Identifying Ocular Corrosives and Severe Irritants). Based on the study results, KBOB is considered a severe eye irritant.

Key value for chemical safety assessment

Skin irritation / corrosion

Link to relevant study records

Reference

Endpoint:

skin irritation: in vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2011-11-22 to 2011-11-25

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: GLP and guideline compliant skin irritation study for lithium bis(oxalato)borate was used for read across and evaluation of skin irritation properties of potassium bis(oxalato)borate on the basis of structural similarity.

Qualifier:

according to guideline

Guideline:

OECD Guideline 404 (Acute Dermal Irritation / Corrosion)

Version / remarks:

24th April 2002

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method B.4 (Acute Toxicity: Dermal Irritation / Corrosion)

Version / remarks:

16th June 2004

Deviations:

no

Qualifier:

according to guideline

Guideline:

EPA OPPTS 870.2500 (Acute Dermal Irritation)

Version / remarks:

August 1998

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Species:

rabbit

Strain:

New Zealand White

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: S & K LAP Kft. 2173 Kartal, Császár út 135, HUNGARY
- Age at study initiation: Young adult rabbits, 10 weeks old
- Weight at study initiation: 3191-3340 g
- Housing: Animals were housed individually in metal cages.
- Diet (e.g. ad libitum): P. Strengthened Female Hare Mixed diet, ad libitum
- Water (e.g. ad libitum): tap water, ad libitum
- Acclimation period: 19 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22 ± 3 °C
- Humidity (%): 30 - 70 % (rel.)
- Photoperiod (hrs dark / hrs light): 12/12

Type of coverage:

occlusive

Preparation of test site:

other: clipped

Vehicle:

unchanged (no vehicle)

Controls:

other: untreated skin served as a control

Amount / concentration applied:

TEST MATERIAL
- Amount(s) applied (volume or weight with unit): 0.5 g

Duration of treatment / exposure:

4 hours

Observation period:

1, 24, 48, 72 hours

Number of animals:

3 males

Details on study design:

TEST SITE
- Area of exposure: back and flanks
- coverage: an approximately area of 6 cm^2 of intact skin
- Type of wrap if used: plastic wrap

REMOVAL OF TEST SUBSTANCE
- Washing (if done): body temperature water used
- Time after start of exposure: 4 hours

SCORING SYSTEM: by Draize et al. (1959)

Irritation parameter:

erythema score

Remarks:

mean

Basis:

animal #1

Time point:

other: 24, 48, 72 h

Score:

0.33

Max. score:

4

Reversibility:

fully reversible within: 72 h

Remarks on result:

other: very slight erythema and crust was found after 24 h

Irritation parameter:

edema score

Remarks:

mean

Basis:

animal #1

Time point:

other: 24, 48, 72 h

Score:

0

Max. score:

4

Irritation parameter:

erythema score

Remarks:

mean

Basis:

animal #2

Time point:

other: 24, 48, 72 h

Score:

0.66

Max. score:

4

Reversibility:

fully reversible within: 72 h

Remarks on result:

other: very slight erythema was detected after 24 and 48 h

Irritation parameter:

edema score

Remarks:

mean

Basis:

animal #2

Time point:

other: 24, 48. 72 h

Score:

0

Max. score:

4

Irritation parameter:

erythema score

Remarks:

mean

Basis:

animal #3

Time point:

other: 24, 48, 72 h

Score:

0.33

Max. score:

4

Reversibility:

fully reversible within: 48 h

Remarks on result:

other: very slight erythema after 24 h

Irritation parameter:

edema score

Remarks:

mean

Basis:

animal #3

Time point:

other: 24, 48, 72 h

Score:

0

Max. score:

4

Read across for evaluation of skin irritation properties of potassium bis(oxalato)borate from the skin irritation in vivo study results of lithium bis(oxalato)borate is justified on the basis of structural similarity of the substances. The bis(oxalato)borate salt part [B(C2O4)2] is the same in both substances and only the cationic part of salts differ (lithium or potassium). Both lithium and potassium belong to alkali-metals.

Interpretation of results:

not irritating

Remarks:

Criteria used for interpretation of results: EU

Conclusions:

Based on the skin irritation study of lithium bis(oxalato)borate the test substance was not irritating to the intact skin of New Zealand white rabbits.
Based on structural similarity, the result can be used for read across when evaluating skin irritation properties of potassium bis(oxalato)borate. The result can be used for classification purposes. For risk assessment, also potassium bis(oxalato)borate can be regarded as not irritating to skin. See also attachment in section 13 (Analogue approach justification).

Executive summary:

The acute skin irritation study of the test item lithium bis(oxalato)borate (LiBOB) was performed in New Zealand White rabbits according to OECD guideline 404 and EU method B.4. The irritation effect of the test item was evaluated according to the Draize method. The test item was administered in pure state, in a single dose of 0.5 g, to the hairless skin of three experimental rabbits. The untreated skin of each animal served as control. After 4 hours the rest of the test item was removed with water. The animals were examined at 1, 24, 48 and 72 hours after the patch removal. One hour after the patch removal very slight and well defined erythema and very slight edema were observed. 24 hours after the patch removal very slight erythema was found in all animals and crust were recorded in one animal. 72 hours after the patch removal no primary irritation symptoms, like erythema and edema or other signs occurred on the treated skin surfaces, so the study was terminated at this time. The animal’s individual mean scores (considering readings at 24, 48 and 72 hours after the patch removal) were as follows:

- erythema: 0.33, 0.66, 0.33

- edema: 0.00, 0.00, 0.00

During the study the control area was symptom-free. General state and the behavior of animals were normal throughout the study period. There were no notable body weight changes during the contact and observation period. The observed symptoms were evaluated as fully reversible alterations. From this follows lithium bis(oxalato)borate is non irritating to the intact skin of New Zealand white rabbits. (TOXICOOP, 2012).

Based on structural similarity, the result can be used for read across when evaluating skin irritation properties of potassium bis(oxalato)borate. Consequently, also potassium bis(oxalato)borate can be regarded as not irritating to skin.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not irritating)

Eye irritation

Link to relevant study records

Reference

Endpoint:

eye irritation: in vitro / ex vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2014-01-15 to 2014-01-22

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP and guideline compliant study

Qualifier:

according to guideline

Guideline:

OECD Guideline 437 (Bovine Corneal Opacity and Permeability Test Method for Identifying Ocular Corrosives and Severe Irritants)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Species:

other: cow

Strain:

not specified

Vehicle:

physiological saline

Controls:

other: not applicable; but in vitro controls

Amount / concentration applied:

20 % in physiological saline (0.9 % NaCl).

Duration of treatment / exposure:

4 hours ± 5 minutes

Observation period (in vivo):

90 minutes

Number of animals or in vitro replicates:

not applicable

Details on study design:

The assay uses isolated corneas from animals freshly slaughtered at an abattoir. Fresh eyes were collected from the abattoir on the test day and transported in HBSS containing Pen/Strep on ice to the laboratory, where cornea preparation was initiated immediately. The eyes were carefully examined for defects and any defective eyes discarded. The tissue surrounding the eyeball was carefully pulled away and the cornea excised, leaving 2-3 mm of sclera. The isolated corneas were stored in a petri dish containing HBSS and again examined for defects before use in the test.

Negative control: physiological saline (0.9 % NaCl)
Positive control: imidazole 20 % in physiological saline (0.9 % NaCl)

Irritation parameter:

in vitro irritation score

Value:

102.43

Irritant / corrosive response data:

As the mean in vitro irritation score for the test item was determined to be > 55 (102.43), the test item is identified as inducing serious eye damage.

Interpretation of results:

Category 1 (irreversible effects on the eye)

Remarks:

Criteria used for interpretation of results: other: UN GHS

Conclusions:

Based on the in vitro eye corrosion/irritation study with bovine corneas, KBOB is considered a severe eye irritant.

Executive summary:

They eye corrosion potential of KBOB was investigated in the in vitro bovine corneal opacity and permeability assay according to OECD Technical Guideline 437 (Bovine Corneal Opacity and Permeability Test Method for Identifying Ocular Corrosives and Severe Irritants).

The test item was suspended in physiological saline (0.9 %) as a concentration of 20 %. Isolated bovine corneas were mounted in corneal holders, and after an initial incubation in RPMI medium (in both anterior and posterior chamber), their opacity was measured with an opacitometer. Three corneas were used as negative controls, positive controls and for the test item, each. 750 μL of the test item or the control substance was introduced into the anterior chamber, and after 4 hours ± 5 minutes of incubation at 32 ± 1 °C, the substances were removed and the epithelium washed with MEM media containing phenol red until free of test substance, then with RPMI, then an opacity measurement was performed. After a 90-minute incubation (32 ± 1 °C) in fresh RPMI with 1 mL of a 5 mg/mL sodium fluorescein solution added to the anterior chamber, the medium from the posterior chamber was removed and its optical density (OD490) at 490 nm was determined, using a spectrophotometer. The initial opacity reading of each cornea was subtracted from the final opacity reading to obtain the change in opacity, corrected by subtracting the average change in opacity observed for the negative controls, and a mean opacity value was calculated for each treatment. The OD490 values were similarly corrected by subtracting a mean blank-well OD490 from each OD490 for a test article, then the average corrected negative-control OD490 from each test-item or positive-control OD490, and a mean OD490 was then calculated for each treatment. The in vitro irritation score (IVIS) was then calculated as the mean opacity value – (15 x mean OC490 value).

The resulting mean in vitro irritation score for the test item was 102.43. According to the evaluation criteria, KBOB is classified into UN GHS Category 1.

Endpoint conclusion

Endpoint conclusion:

adverse effect observed (irritating)

Respiratory irritation

Endpoint conclusion

Endpoint conclusion:

no study available

Additional information

Justification for selection of skin irritation / corrosion endpoint:
GLP guideline study (in vivo) of structurally similar substance

Justification for selection of eye irritation endpoint:
GLP guideline study

Effects on eye irritation: corrosive

Justification for classification or non-classification

The substance is classified as non-corrosive and non-irritating to skin and highly corrosive to eyes, based on study results.