3,4,5,6-tetrachloro-2-(1,4,5,8-tetrabromo-6-hydroxy-3-oxoxanthen-9-yl)benzoic acid

Endpoint summary

Description of key information

Skin irritation/corrosion:

The test item 3,4,5,6-tetrachloro-2-(1,4,5,8-tetrabromo-6-hydroxy-3-oxoxanthen-9-yl)benzoic acid (CAS No. 18472-87-2) was applied to shorn skin of 5 male and 5 female animals at 2000 mg/kg body weight. Administration of the test item at 2000 mg/kg did not result in any skin reaction at the site of application during the study period of 14 days. Also, the erythema and edema score of rats was calculated as 0.  Administration of the test item did not result in any signs of toxicity and mortality during the study period of 14 days. Animals exhibited normal body weight gain through the study period of 14 days. Gross pathological examination did not reveal any abnormalities attributable to the treatment. 

Hence, it was concluded that 3,4,5,6-tetrachloro-2-(1,4,5,8-tetrabromo-6-hydroxy-3-oxoxanthen-9-yl)benzoic acid (CAS No. 18472-87-2) was Non-Irritating to the skin of Sprague Dawley rats under the experimental conditions tested and Classified as “Category- Unclassified” as per CLP Classification.

 

Eye irritation :

The ocular irritation potential of target chemical was assessedin various in- vitro and in-vivo experimental studies.Based on the available studies,it can be concluded that the test chemical is unable to cause eye irritation and considered as irritating. Comparing the above annotations with the criteria of CLP regulation, it can be classified under the category “Category 2".

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

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Justification for type of information:

Data is from experimental study report.

Qualifier:

according to guideline

Guideline:

other: OECD Guideline 402 (Acute dermal toxicity)

Principles of method if other than guideline:

The study now reported was designed and conducted to determine the dermal Irritation/corrosion potential of 3,4,5,6-tetrachloro-2-(1,4,5,8- tetrabromo-6-hydroxy-3-oxoxanthen-9-yl)benzoic acid (CAS No. 18472-87-2) in Sprague Dawley rats. This study was performed as per OECD guideline No. 402.

GLP compliance:

yes

Specific details on test material used for the study:

SOURCE OF TEST MATERIAL
- Test Item: 3,4,5,6-tetrachloro-2-(1,4,5,8-tetrabromo-6-hydroxy-3-oxoxanthen-9-yl)benzoic acid (CAS No.18472-87-2)
- Source of test material: Sustainability Support Services (Europe) AB
- Lot/batch No.of test material: FG/15-16/0790
- Manufacturing Date: June, 2015
- Expiration date of the lot/batch: May, 2023
- Purity test date: No data
- Consistency: Solid, powder
- Colour: Red

RADIOLABELLING INFORMATION (not applicable)
- Radiochemical purity: N/A
- Specific activity: N/A
- Locations of the label: N/A
- Expiration date of radiochemical substance: N/A

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: Ambient Temperature
- Stability under test conditions: No data
- Solubility and stability of the test substance in the solvent/vehicle: No data
- Reactivity of the test substance with the solvent/vehicle of the cell culture medium: No data

TREATMENT OF TEST MATERIAL PRIOR TO TESTING
- Treatment of test material prior to testing: Test item was moistened with distilled water before application.
- Preliminary purification step (if any):No data
- Final dilution of a dissolved solid, stock liquid or gel: No data
- Final preparation of a solid: No data

FORM AS APPLIED IN THE TEST: Paste

OTHER SPECIFICS:
Safety Precautions : Safety precautions included use of protective clothing, gloves, masks and eye protection (glasses).

Species:

rat

Strain:

Sprague-Dawley

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: National Institute of Biosciences, Pune.
- Age at study initiation: Young adult male and female rats aged between 6 – 9 weeks were used.
- Weight at study initiation: The weight range of approximately 218.4 to 256.4 grams at initiation of dosing were used.
Body weights at the start :
Male
Mean : 246.68 g (= 100 %)
Minimum : 238.5 g (- 3.32 %)
Maximum : 256.4 g (+ 3.94 %)
Total No. of animals : 5
Female
Mean : 224.90 g (= 100 %)
Minimum : 218.4 g (- 2.89 %)
Maximum : 235.6 g (+ 4.76 %)
Total No. of animals : 5
- Housing: The rats were individually housed in polycarbonate cages with paddy husk as bedding.
- Diet (e.g. ad libitum): Rodent feed supplied by the Nutrivet Life Sciences, Pune, was provided ad libitum from individual feeders.
- Water (e.g. ad libitum): Water was provided ad libitum from individual bottles attached to the cages. All water was from a local source and passed through the reverse osmosis membrane before use.
- Acclimation period : 5 days.

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 20.0 to 22.3 degree centigrade.
- Humidity (%): 55.7% to 59.6%.
- Air changes (per hr): Ten to fifteen air changes per hour.
- Photoperiod (hrs dark / hrs light): An artificial light and dark cycle of 12 hours each was provided to the room.

IN-LIFE DATES: 28-09-2016 to 13-10-2016

Type of coverage:

semiocclusive

Preparation of test site:

clipped

Vehicle:

water

Remarks:

Distilled water

Controls:

not specified

Amount / concentration applied:

TEST MATERIAL
- Amount(s) applied (volume or weight with unit): 2000 mg/kg bw
- Concentration (if solution): no

VEHICLE (not used)
- Amount(s) applied (volume or weight with unit):No data
- Concentration (if solution): No data
- Lot/batch no. (if required): No data
- Purity: No data

NEGATIVE CONTROL
- Amount(s) applied (volume or weight): No data
- Concentration (if solution): No data

POSITIVE CONTROL
- Amount(s) applied (volume or weight): No data
- Concentration (if solution): No data

Duration of treatment / exposure:

24 hrs.

Observation period:

14 days

Number of animals:

10 (5/sex).

Details on study design:

TEST SITE
- Area of exposure: Trunk (dorsal surface and sides from scapular to pelvic area)
- % coverage: Approximately 10% of the total body surface area.
- Type of wrap if used: Porous gauze dressing and non-irritating tape.

REMOVAL OF TEST SUBSTANCE
- Washing (if done): Distilled water was used to remove residual test item.

OBSERVATION TIME POINTS
(indicate if minutes, hours or days) : Dermal reaction was observed daily for study period of 14 days.

SCORING SYSTEM: Draize Method.

OTHER OBSERVATIONS
Type and Frequency of Tests, Analyses and Measurements

Viability: Twice daily.

Clinical Observations and General Appearance:
Animals were observed for clinical signs, mortality, until sacrifice.
Onset, duration and severity of any sign were recorded. The clinical signs and mortality observations were conducted at 10, 30, 60 minutes, 2, 4 and 6 hours on the day of dosing and once daily thereafter for 14 day. Daily observation was done as far as possible at the same time.
The observations were included general clinical signs, observations of eyes, mucous membranes, respiratory, circulatory system and behavior pattern.

Body weights:
Individual animal body weights were recorded pre-test (prior to administration of the test item), day 7 and at termination on day 14.

Gross Pathology:
Necropsy was performed on animals surviving at the end of the study. Macroscopic examination of all the orifices, cavities and tissues were made and the findings were recorded. All animals surviving the study period were sacrificed by the carbon dioxide asphyxiation technique (day 15).

Histopathology:
No gross abnormalities were observed in animals sacrificed terminally hence, no histopathology was performed.

Irritation parameter:

erythema score

Basis:

mean

Time point:

14 d

Score:

0

Max. score:

4

Reversibility:

other: Not applicable

Remarks on result:

no indication of irritation

Irritation parameter:

edema score

Basis:

mean

Time point:

14 d

Score:

0

Max. score:

4

Reversibility:

other: not applicable

Remarks on result:

no indication of irritation

Irritant / corrosive response data:

Overall result:
Sex : Male
Group I -
Animal treated at the dose level of 2000 mg/kg body weight did not result in any skin reaction during the study period of 14 days.

Sex : Female
Group I -
Animal treated at the dose level of 2000 mg/kg body weight did not result in any skin reaction during the study period of 14 days.

Other effects:

Other effects
Clinical Signs of Toxicity and Mortality
Sex : Male
Group I -
Animal treated at the dose level of 2000 mg/kg body weight did not result in any signs of toxicity during the study period of 14 days. All animals survived through the study period of 14 days.

Sex : Female
Group I -
Animal treated at the dose level of 2000 mg/kg body weight did not result in any signs of toxicity during the study period of 14 days. All animals survived through the study period of 14 days.

Body Weight
Sex : Male
Group I (2000 mg/kg) - Percent body weight gain after 7 days and 14 days was found to be 11.17% and 20.64% respectively.

Sex : Female
Group I (2000 mg/kg) - Percent body weight gain after 7 days and 14 days was found to be 6.33% and 11.63% respectively.

Gross Pathological Findings
Gross pathological examination did not reveal any abnormalities in animals from 2000 mg/kg dose group.

Table No. I

Summary of Clinical Signs of Toxicity and Mortality

Test System : Sprague Dawley Rat

Sex : Male

Group  No.	Dose mg/kg	Observed Signs	Total Number of Animals	Animal Nos.	Period of signs in days  From - to	Mortality
I	2000	No clinical signs observed	5	1 - 5	0 - 14	0/5

 

Sex : Female 

Group  No.	Dose mg/kg	Observed Signs	Total Number of Animals	Animal Nos.	Period of signs in days  From - to	Mortality
I	2000	No clinical signs observed	5	6 - 10	0 - 14	0/5

 

 Table No. II

 Summary of Evaluation of Dermal Reaction 

Test System : Sprague Dawley Rat

Sex : Male 

Group  No.	Dose mg/kg	Dermal Reaction	Total Number of Animals	Animal Nos.	Period of signs in days  From - to	Mortality
I	2000	No dermal reaction observed	5	1 - 5	0 - 14	0/5

 

Sex : Female 

Group  No.	Dose mg/kg	Dermal Reaction	Total Number of Animals	Animal Nos.	Period of signs in days  From - to	Mortality
I	2000	No dermal reaction observed	5	6 - 10	0 - 14	0/5

 

Table No.III 

Mean Body Weight and Percent Body Weight Gain (g) 

Test System : Sprague Dawley Rat

Sex : Male 

Group No.	Dose (mg/kg body weight)		Body weight Day 0	Body weight Day 7	% body weight gain day 0-7	Body weight Day 14	% body weight gain day 7- 14	% body weight gain day 0- 14
I	2000	Mean	246.68	274.24	11.17	297.50	8.52	20.64
		± SD	7.30	8.65	1.27	6.88	1.91	2.54

 

 

Sex : Female

Group No.	Dose (mg/kg body weight)		Body weight Day 0	Body weight Day 7	% body weight gain day 0-7	Body weight Day 14	% body weight gain day 7- 14	% body weight gain day 0- 14
I	2000	Mean	224.90	239.14	6.33	251.06	4.99	11.63
		± SD	6.59	7.46	0.72	7.69	1.36	0.81

 

 Table No.IV 

Summary of Gross Pathological Findings

Test System : Sprague Dawley Rat 

Sex : Male

Group No.	Dose mg/kg	Animal Numbers	Animal Fate	Gross Pathological Findings
I	2000	1 - 5	TS	No abnormality detected

 

Sex : Female

Group No.	Dose mg/kg	Animal Numbers	Animal Fate	Gross Pathological Findings
I	2000	6 - 10	TS	No abnormality detected

 TS = Terminal Sacrifice

 

Interpretation of results:

other: Not irritating

Conclusions:

The test item 3,4,5,6-tetrachloro-2-(1,4,5,8-tetrabromo-6-hydroxy-3-oxoxanthen-9-yl)benzoic acid (CAS No. 18472-87-2) was applied to shorn skin of 5 male and 5 female animals at 2000 mg/kg body weight. Administration of the test item at 2000 mg/kg did not result in any skin reaction at the site of application during the study period of 14 days. Also, the erythema and edema score of rats was calculated as 0.  Administration of the test item did not result in any signs of toxicity and mortality during the study period of 14 days. Animals exhibited normal body weight gain through the study period of 14 days. Gross pathological examination did not reveal any abnormalities attributable to the treatment. 
Hence, it was concluded that 3,4,5,6-tetrachloro-2-(1,4,5,8-tetrabromo-6-hydroxy-3-oxoxanthen-9-yl)benzoic acid (CAS No. 18472-87-2) was Non-Irritating to the skin of Sprague Dawley rats under the experimental conditions tested and Classified as “Category- Unclassified” as per CLP Classification.

Executive summary:

The study now reported was designed and conducted to determine the dermal Irritation/corrosion potential of 3,4,5,6-tetrachloro-2-(1,4,5,8-tetrabromo-6-hydroxy-3-oxoxanthen-9-yl)benzoic acid (CAS No. 18472-87-2) in Sprague Dawley rats. This study was performed as per OECD guideline No. 402. Ten rats (5 male and 5 female) were used for conducting dermal irritation/ corrosion study.

 

The animals were kept in their cages for at least 5 days prior to administration for acclimatization to the laboratory condition and after acclimatization period, animals were randomly selected. Approximately 24 hours before application, the hair of each rat was closely clipped from the trunk (dorsal surface and sides from scapular to pelvic area) with an electric clipper, so as to expose at least 10% of the body surface area. The test item was moistened with distilled water. The test item was applied onto the exposed skin of the animal, taking care to spread the test item evenly over the entire area of approximately 10% of the total body surface area or as much of the area as can reasonably be covered. The test item was held in contact with the skin using a porous gauze dressing and non irritating tape around the animal to cover the exposure site for first 24 hours exposure period. Elizabethan collar was placed on each animal for first 24 hours after application of the test item. These collars prevent ingestion of test item. Following 24 hours of exposure, the wrapping was removed and the test site wiped free of excess test item. Distilled water was used to remove residual test item.

 

The test item 3,4,5,6-tetrachloro-2-(1,4,5,8-tetrabromo-6-hydroxy-3-oxoxanthen-9-yl)benzoic acid (CAS No. 18472-87-2) was applied to shorn skin of 5 male and 5 female animals at 2000 mg/kg body weight. Administration of the test item at 2000 mg/kg did not result in any skin reaction at the site of application during the study period of 14 days. Also, the erythema and edema score of rats was calculated as 0.  Administration of the test item did not result in any signs of toxicity and mortality during the study period of 14 days. Animals exhibited normal body weight gain through the study period of 14 days. Gross pathological examination did not reveal any abnormalities attributable to the treatment.

 

Hence, it was concluded that 3,4,5,6-tetrachloro-2-(1,4,5,8-tetrabromo-6-hydroxy-3-oxoxanthen-9-yl)benzoic acid (CAS No. 18472-87-2) was Non-Irritating to the skin of Sprague Dawley rats under the experimental conditions tested and Classified as “Category- Unclassified” as per CLP Classification.

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

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Justification for type of information:

Data is from experimental study report.

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)

Principles of method if other than guideline:

The purpose of this study was to assess potential for the test article to be ocular irritants. The ocular irritation potential of a test article may be predicted by measurement of its cytotoxic effect, as reflected in the (MTT) assay, in the MatTek EpiOcular™ model

GLP compliance:

no

Specific details on test material used for the study:

RADIOLABELLING INFORMATION (Not applicable)
- Radiochemical purity: N/A
- Specific activity: N/A
- Locations of the label: N/A
- Expiration date of radiochemical substance: N/A

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: Room temperature / Fridge storage
- Stability under test conditions: No data available
- Solubility and stability of the test substance in the solvent/vehicle: No data available
- Reactivity of the test substance with the solvent/vehicle of the cell culture medium: No data available

TREATMENT OF TEST MATERIAL PRIOR TO TESTING
- Treatment of test material prior to testing: The test article tested as provided neat (undiluted).
- Preliminary purification step (if any): No data available
- Final dilution of a dissolved solid, stock liquid or gel: No data available
- Final preparation of a solid: No data available

FORM AS APPLIED IN THE TEST:solid

Species:

human

Strain:

other: Not applicable

Details on test animals or tissues and environmental conditions:

- Description of the cell system used:
The normal human-derived keratinocytes were cultured at the air-liquid interface in a chemically defined medium on a permeable polycarbonate insert (surface 0.5 cm2). They were cultured in chemically defined serum free medium to form a multi-layered epithelium similar to that found in native corneal mucosa. Each lot of tissues was Quality Assured by MatTek according to specific QC standards including: histology, tissue viability (MTT mean optical density), reproducibility (SD) and tissue thickness.

- Test System Identification
All of the EpiOcular™ 3-dimensional human tissues used in this study were identified by the date of arrival and the lot number. Certificate of Analysis for the tissues is included in this report. Tissue plates were appropriately labeled with study information. Bias was not a factor in this test system.
- Justification of the test method and considerations regarding applicability
EpiOcularTM Eye Irritation (OCL) by MatTek In Vitro Life Science Laboratories, Bratislava, Slovakien

The test articles and controls were evaluated for potential ocular irritancy using the EpiOcular™ 3 dimensional human tissue model purchased from MatTek,In Vitro Life Science Lab. (Bratislava, Slovakia).The EpiOcular tissue construct is a nonkeratinized epithelium prepared from normal human keratinocytes (MatTek). It models the cornea epithelium with progressively stratified, but not cornified cells. These cells are not transformed or transfected with genes to induce an extended life span in culture. The “tissue” is prepared in inserts with a porous membrane through which the nutrients pass to the cells. A cell suspension is seeded into the insert in specialized medium. After an initial period of submerged culture, the medium is removed from the top of the tissue so that the epithelial surface is in direct contact with the air. This allows the test material to be directly applied to the epithelial surface in a fashion similar to how the corneal epithelium would be exposed in vivo. Each lot of tissues was Quality Assured by MatTek, Inc. according to specific QC standards including: histology (cell layers), tissue viability (MTT mean optical density) and reproducibility (SD).

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 mg of solid test chemical
- Concentration (if solution): neat (undiluted)

VEHICLE (no vehicle)
- Amount(s) applied (volume or weight with unit): none
- Concentration (if solution): none
- Lot/batch no. (if required): none
- Purity: none

NEGATIVE CONTROL
- Amount(s) applied (volume or weight): 50 μL
- Concentration (if solution): neat

POSITIVE CONTROL
- Amount(s) applied (volume or weight): 50 μL
- Concentration (if solution): neat

Duration of treatment / exposure:

Tissues were exposed for approximately 6 hrs ± 15 min for solid test articles, and controls, at approximately 37°C, 5% CO2 in a humidified incubator.

Observation period (in vivo):

Not applicable.

Duration of post- treatment incubation (in vitro):

Following the washing and post soak, the tissues were rinsed and incubated at approximately 37°C, 5% CO2 in a humidified incubator for a post-exposure recovery time of 18 hours for solid test chemicals and controls.

Number of animals or in vitro replicates:

2 tissues were used for test compound and control.

Details on study design:

- Details of the test procedure used
The tissues were exposed to the test article neat (undiluted). EpiOcular™ tissues were purchased from MatTek. Quality control of the tissues was performed by MatTek and the Certificate of Analysis (CoA)
for the tissues is provided and is kept in the study binder. Tissues were exposed for approximately 6 hrs ± 15 min for solid test articles and controls at approximately 37°C, 5% CO2 in a humidified incubator.
After the exposure, the test article was rinsed off the tissues and the tissues were soaked in media for ~25 minutes for solid test articles and controls.Following the washing and post soak, the tissues were rinsed and incubated at approximately 37°C, 5% CO2 in a humidified incubator for a post-exposure recovery time of 18 hours for solid test chemicals and controls.Tissue viability was assessed by 3-(4,5-dimethylthiazol- 2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay.

- MTT Auto reduction and colouring assessment
MTT Pre-test
The test article was assessed for the potential to interfere with the assay. Approximately 50 µL of liquid test article was added to 1 mL of MTT media (~1 mg/mL) and incubated in a humidified incubator at approximately 37°C and approximately 5% CO2 for 3 hours. 50 µL of ultrapure water was used as a negative control.
- Test Article Color Test
Approximately 50 µL of liquid test article was added to 1.0 mL of ultrapure water and 2.0 mL isopropanol and incubated in a humidified incubator at approximately 37°C and approximately 5% CO2 for 2 hours, 04 minutes and 35 seconds. Samples were then added to the wells of a clear 96-well plate and the plate was read on a Thermo Scientific Multiskan FC Microplate Photometer to 570 nm. Test articles that tested positive for excessive coloration (OD >0.08) were assessed on living-tissue controls that were incubated in both culture media and MTT media as well (n=3 for both conditions).

- MTT Assay:
Inserts are removed from the 24-well plate after 3 hrs of incubation and the bottom of the insert is blotted on absorbent material, and then transferred to a pre-labeled 6-well plate containing 1 ml isopropanol in each well so that no isopropanol is flowing into the insert. At the end of the non-submerged extraction inserts and tissues are discarded without piercing and 1 ml of isopropanol is added into each well. The extract solution is mixed and the optical density of the extracted formazan (200 μL/well of a 96-well plate) was determined using Thermo Scientific Multiskan FC Microplate Photometer at 570 nm. Relative cell viability was calculated for each tissue as % of the mean negative control tissues.

- Evaluation of Test Article in the cell Models
1. Cell System:
Upon receipt, the MatTek EpiOcular™ tissue cultures were placed in 1.0 mL of fresh Maintenance medium (in a 6-well plate) for 60 minutes. After the 60 minutes incubation, the Maintenance medium was exchanged with fresh medium and the tissues were incubated overnight (16-24 hrs) at approximately 37°C, approximately 5% CO2 in a humidified incubator.
2. Control and Test Article Exposures:
20 µL of calcium and magnesium free DPBS was added to each tissue and the tissues placed back into the incubator for 30 minutes. The controls and the test article will be applied topically to tissues by pipette.2 tissues will be used per test compound and control.
a)Controls: 50 µL of negative control sterile ultrapure water and positive control methyl acetate were added to the tissues. The tissues were placed into the ~37°C humidified incubator with 5% CO2 for the approximately 30 minute exposure time.
b)Test Article: When a solid was tested, 50 mg of the solid were added to the tissues. The tissues were placed into the ~37°C humidified incubator with 5% CO2 for the approximately 6 hrs ± 15 min.
3. Post exposure treatment:
After the exposure, the tissues were rinsed 20 times with sterile of DPBS to remove test material. The apical surface was gently blotted with a cotton swab and cultures were immediately transferred to a 12-well plate containing 5 mL of media per well. Tissues exposed to liquid test articles (and the respective control) were incubated, submerged in the media for ~12 minutes at room temperature.For liquid test articles, tissues, Tissuses were then transferred to 6-well plates containing 1.0 mL fresh Maintenance medium per well and incubated for a post-exposure recovery period for 2 hours at approximately 37 degC, 5% CO2 in a humidified incubator.
- Doses of test chemical and control substances used
Test Article:
When a solid was tested, 6 hours of the solid were added to the tissues. The tissues were placed into the ~37°C humidified incubator with 5% CO2 for the approximately 6 hrs ± 15 min.
Controls: 50 µL of negative control sterile ultrapure water, positive control methyl acetate were added to the tissues. The tissues were placed into the ~37°C humidified incubator with 5% CO2 for the approximately 30 minute exposure time.

- Duration and temperature of exposure, post-exposure immersion and post-exposure incubation periods:
Tissues were exposed for approximately 6 hours for solid test articles and controls, at approximately37°C, 5% CO2 in a humidified incubator.
Following the post soak, the tissues were rinsed and incubated at approximately 37°C, 5% CO2 in a humidified incubator for a post-exposure recovery time totaling 18 hours for solid test articles and controls.

- Justification for the use of a different negative control than ultrapure H2O (Not applicable)
- Justification for the use of a different positive control than neat methyl acetate (Not applicable)
- Number of tissue replicates used per test chemical and controls: 2 tissues were used for test compound and control.
- Description of the method used to quantify MTT formazan
The blue formazan salt was extracted by placing the tissue insterts in 1 mL isopropanol in a 6-well plate. The extraction for solid exposed tissues was 3 hrs incubation. After an addition of 1 ml isopropanol and mixing, the optical density of the extracted formazan (200μL/well of a 96-well plate) was determined using a Thermo Scientific Multiskan FC Microplate Photometer at 570 nm.

- Description of evaluation criteria used including the justification for the selection of the cut-off point for
the prediction model
Calculations and Statistical Methods
MTT Assay
Blanks:
· The OD mean from all replicates for each plate (ODblank).
Negative Controls (NC):
· The blank corrected value was calculated: ODNC= ODNCraw– ODblank.
· The OD mean per NC tissue was calculated.
· The mean OD for all tissues corresponds to 100% viability.
· The mean, standard deviation (SD), standard error of the mean (SEM) and the percent coefficient of variation (% CV) was calculated.
ODblank= optical density of blank samples (isopropanol alone).
ODNCraw= optical density negative control samples.
ODNC= optical density of negative control samples after background subtraction.
Positive Control (PC):
· Calculate the blank corrected value: ODPC= ODPCraw– ODblank.
· The OD mean per PC tissue was calculated.
· The viability per tissue was calculated: %PC = [ODPC/ mean ODNC] x 100.
· The mean viability for all tissues was calculated: Mean PC = Σ %PC / number of tissues.
· The standard deviation (SD), standard error of the meanthe mean (SEM) and the percent coefficient of variation (% CV) was calculated.
ODPCraw= optical density positive control samples.
ODPC= optical density of positive control samples after background subtraction.
Tested Articles:
· Calculate the blank corrected value ODTT= ODTTraw– ODblank.
· The OD mean per tissue is calculated.
· The viability per tissue is calculated: %TT = [ODTT/ mean ODNC] x 100.
· The mean viability for all tissues is calculated: Mean TT = Σ %TT / number of tissues.
· The standard deviation (SD) and the percent coefficient of variation (% CV)for the controls and the test articles will be calculated.
ODTTraw= optical density test article samples.
ODPC= optical density of test article samples after background subtraction.
Data Correction Procedure for MTT Interfering Compounds
True viability = Viability of treated tissue – Interference from test article = ODtvt – ODkt where ODkt =
(mean ODtkt – mean ODukt).
ODtvt = optical density of treated viable tissue
ODkt = optical density of killed tissues
ODtkt = optical density of treated killed tissue
ODukt = optical density of untreated killed tissue (NC treated tissue)
Data Correction Procedure for Colored Compounds
True viability = Viability of treated tissue incubated in MTT media – Viability of treated tissue incubated in
media without MTT = ODtvt – ODvt.
ODtvt = optical density of treated viable tissue incubated in MTT media
ODvt = optical density of viable tissues incubated in media alone.
Proposed Statistical methods
The mean, standard deviation (SD) and the percent coefficient of variation (% CV) for the controls and the test article will be calculated.
- Evaluation of data
The results of the assay was evaluated and compared to negative control.
Table: Irritancy Prediction
In VitroResults In VivoPrediction
Mean tissue viability ≤60% Irritant (I) – Category 1 or 2
Mean tissue viability >60% Non-irritant (NI) – No Category
- Assay quality controls
- Negative Controls (NC)
The assay is meeting the acceptance criterion if the mean viability of the NC in terms of Optical Density(OD570) of the NC tissues (treated with sterile ultrapure water) in the MTT assay are >0.8 to <2.5. This is an indicator of tissue viability following shipping and conditions under use.
- Positive Controls (PC)
Methyl acetate was used as a PC and tested concurrently with the test article. The assay is meeting the acceptance criteria if the viability of the PC is <50% of the negative control.
- Standard Deviation (SD)
Each test of ocular irritancy potential is predicted from the mean viability determined on 2 single tissues. The assay meets the acceptance criteria if SD calculated from individual percent tissue viabilities of the
replicates is <18% for three replicate tissues.

Irritation parameter:

other: mean % tissue viability

Run / experiment:

Run 1

Value:

6.6

Vehicle controls validity:

not specified

Negative controls validity:

valid

Positive controls validity:

valid

Remarks on result:

other: Mean of OD: 0.122; irritant

Other effects / acceptance of results:

The MTT data show the assay quality controls were met.

The analysis contains the results of so called corrected adsorbance since the colors themselves disturbed the MTT salt. Thus, a test with only the colored chemicals were conducted without adding the MTT salt during the MTT analysis. Hence, the results presented here are the corrected result (i.e. the results from the assay with MTT minus the results from the assay without MTT) and shows the true, corrected MTT analysis without the effect of the chemical absorbance included for test chemical.

Interpretation of results:

other: irritating

Conclusions:

The ocular irritation potential of test article was determined according to the OECD 492 test guideline followed for this study. The mean of OD for test chemical was determined to be 0.122. The mean % tissue viability of test chemical was determined to be 6.6%. Thus, test chemical was considered to be irritating to the human eyes.

Executive summary:

The ocular irritation potential of test article was determined according to the OECD 492 test guideline for this study. The MatTek EpiOcular™ model was used to assess the potential ocular irritation of the test articles by determining the viability of the tissues following exposure to the test article via MTT. Tissues were exposed to liquid test articles and controls for ~30 minutes, followed by a ~12 minute post-soak and approximately 2 hour recovery after the post-soak. The viability of each tissue was determined by MTT assay.

The MTT data show the assay quality controls were met, passing the acceptance criteria.

The mean of OD for test chemical was determined to be 0.122.The mean % tissue viability of test chemical was determined to be 6.6%. Hence, under the experimental test conditions it was concluded that test chemical was considered to be irritating to the human eyes.

Endpoint conclusion

Endpoint conclusion:

adverse effect observed (irritating)

Additional information

Skin irritation / corrosion:

The test compound 3,4,5,6-tetrachloro-2-(1,4,5,8-tetrabromo-6-hydroxy-3-oxoxanthen-9-yl)benzoic acid (CAS Number: 18472-87-2) was investigated for its dermal irritation potential to a greater or lesser extent. Often are the studies based on in vivo experiments in rodents for 3,4,5,6-tetrachloro-2-(1,4,5,8-tetrabromo-6-hydroxy-3-oxoxanthen-9-yl)benzoic acid (CAS Number: 18472-87-2) along with the study available on structurally similar read across substance Disodium 2-(2,4,5,7-tetraiodo-6-oxido-3-oxoxanthen-9-yl)benzoate (CAS No. 16423-68-0). The studies are summarized as below:  

 

The study now reported was designed and conducted at IIT, Pune (2016) to determine the dermal Irritation/corrosion potential of 3,4,5,6-tetrachloro-2-(1,4,5,8-tetrabromo-6-hydroxy-3-oxoxanthen-9-yl)benzoic acid (CAS No. 18472-87-2) in Sprague Dawley rats. This study was performed as per OECD guideline No. 402. Ten rats (5 male and 5 female) were used for conducting dermal irritation/ corrosion study.  

The animals were kept in their cages for at least 5 days prior to administration for acclimatization to the laboratory condition and after acclimatization period, animals were randomly selected. Approximately 24 hours before application, the hair of each rat was closely clipped from the trunk (dorsal surface and sides from scapular to pelvic area) with an electric clipper, so as to expose at least 10% of the body surface area. The test item was moistened with distilled water. The test item was applied onto the exposed skin of the animal, taking care to spread the test item evenly over the entire area of approximately 10% of the total body surface area or as much of the area as can reasonably be covered. The test item was held in contact with the skin using a porous gauze dressing and non irritating tape around the animal to cover the exposure site for first 24 hours exposure period. Elizabethan collar was placed on each animal for first 24 hours after application of the test item. These collars prevent ingestion of test item. Following 24 hours of exposure, the wrapping was removed and the test site wiped free of excess test item. Distilled water was used to remove residual test item.  

The test item 3,4,5,6-tetrachloro-2-(1,4,5,8-tetrabromo-6-hydroxy-3-oxoxanthen-9-yl)benzoic acid (CAS No. 18472-87-2) was applied to shorn skin of 5 male and 5 female animals at 2000 mg/kg body weight. Administration of the test item at 2000 mg/kg did not result in any skin reaction at the site of application during the study period of 14 days. Also, the erythema and edema score of rats was calculated as 0.  Administration of the test item did not result in any signs of toxicity and mortality during the study period of 14 days. Animals exhibited normal body weight gain through the study period of 14 days. Gross pathological examination did not reveal any abnormalities attributable to the treatment. Hence, it was concluded that 3,4,5,6-tetrachloro-2-(1,4,5,8-tetrabromo-6-hydroxy-3-oxoxanthen-9-yl)benzoic acid (CAS No. 18472-87-2) was Non-Irritating to the skin of Sprague Dawley rats under the experimental conditions tested. 

 

In a further skin irritation test for 3,4,5,6-tetrachloro-2-(1,4,5,8-tetrabromo-6-hydroxy-3-oxoxanthen-9-yl)benzoic acid (Acid Red 92) (CAS No. 18472 -87 -2) by topical semi-occlusive application of 0.5 g to the intact left flank of each of three young adult New Zealand White rabbits (published in a SCCNFP report). The duration of the treatment was four hours. The scoring of skin reactions was performed 1, 24, 48 and 72 hours, as well as 7, 10 and 14 days after removal of the dressing. The test item did not elicit any skin reactions at the application site of any animal (all scores = 0). The individual mean score for erythema/eschar and edema for each of the three animals was 0. A light to marked red staining was apparent in all animals for the majority of the observation period and was still present in one animal 14 days after removal of the dressing, the end of the observation period for all animals. No corrosive effects were noted on the treated skin of any animal at any of the measuring intervals.

Hence, 3,4,5,6-tetrachloro-2-(1,4,5,8-tetrabromo-6-hydroxy-3-oxoxanthen-9-yl)benzoic acid (Acid Red 92) (CAS No. 18472 -87 -2) is considered to be not irritating to the skin of New Zealand Albino rabbits. 

 

Thus, on the basis of the above studies for target substance, it was concluded that 3,4,5,6-tetrachloro-2-(1,4,5,8-tetrabromo-6-hydroxy-3-oxoxanthen-9-yl)benzoic acid (CAS Number: 18472-87-2) is non-Irritating to the skin of rats and rabbits under the experimental conditions tested and Classified as “Category- Unclassified” as per CLP Classification.

 

Eye irritation:

In different studies, the test chemical has been investigated for potential for ocular irritation to a greater or lesser extent. The studies are based on in- vitro and in-vivo experimental conducted in rabbits conducted which have been summarized as below:

 

The ocular irritation potential of test article was determined according to the OECD 492 test guideline for this study. The MatTek EpiOcular™ model was used to assess the potential ocular irritation of the test articles by determining the viability of the tissues following exposure to the test article via MTT. Tissues were exposed to liquid test articles and controls for ~30 minutes, followed by a ~12 minute post-soak and approximately 2 hour recovery after the post-soak. The viability of each tissue was determined by MTT assay.

The MTT data show the assay quality controls were met, passing the acceptance criteria.

The mean of OD for test chemical was determined to be 0.122.The mean % tissue viability of test chemical was determined to be 6.6%. Hence, under the experimental test conditions it was concluded that test chemical was considered to be irritating to the human eyes.

 

The Vitrigel-EIT method was conducted by Hiroyuki Yamaguchi et. al.,(J. Appl. Toxicol. 2016; 36: 1025–1037) to check the eye irritation potential of the test substance Phloxine B. The Vitrigel-EIT method is composed of two parts, i.e., the construction of a human corneal epithelium (HCE) model in a collagen vitrigel membrane chamber and the prediction of eye irritancy by analyzing the time-dependent profile of transepithelial electrical resistance values for 3 min after exposing a chemical to the HCE model. A SV40-immortalized Human Corneal Epithelium cell strain (HCE-T cells, RCB no. 2280) was obtained from the RIKEN BioResource Center (Tsukuba, Japan). The test chemical solution was prepared in a culture medium at a concentration of 2.5 (weight/volume) % appropriate for measuring TEER values without being influenced by the test chemical-dependent electrical resistance.

Here, the chemical was dissolved in the medium by using an appropriate technique(s) as follows: vortex mixing within 1 min, sonication within 20 min and/or heating in a water bath <70 °C. In case test chemical was insoluble or immiscible by the above technique( s), the test chemical solution was prepared as a homogeneous suspension that the chemical was mixed well in the medium by vortex within 1 min immediately before use. The pH level of each 2.5 w/v % test chemical solution was measured using Universal pH test paper from ADVANTEC (Tokyo, Japan). The HCE models on day 6 were subjected to the exposure experiment of test chemicals. At first, 500 μl of culture medium was poured in the chamber and the value of the Rsample, before chemical exposures, was measured to obtain the initial TEER value of each model. Next, the medium inside the chamber was changed to 500 μl of test chemical solution and the periodical values of Rsample were measured by the TEER recorder at intervals of 10 s for 3 min after exposure of each test solution. Three independent models were subjected to the exposure experiment for each test solution to plot the average time-dependent profile of TEER values on a chart. The chemical exposure experiment was conducted in the ambient temperature of 28 ± 2 °C. Hence, it was concluded that test chemical was irritating to the human eyes under the experimental conditions tested.

 

In a further eye irritation study by Takahashi et al.( Toxicology in Vitro 25 (2011) 1425–1434), the Short Time Exposure (STE) test method based in vitro assay was performed on a confluent monolayer of Staten’s Seruminstitut Rabbit Cornea (SIRC) cells, cultured on a 96-well polycarbonate microplate. After five-minute exposure to a test chemical, the cytotoxicity is quantitatively measured as the relative viability of SIRC cells using the MTT assay. Decreased cll viability is used to predict potential adverse effects leading to ocular damage. On the basis of the relative viability index of -0.1 obtained in STE test, the test chemical is an irritant. Similarly from the Draize 100% data the test chemical was found to be an irritant. So, based on the scores of Draize test the test chemical was classified under CLP category 2 as per the CLP classification criteria.

 

 

Furthermore, in vivo Draize tests were conducted by Ohno et. al., (Toxicology in Vitro 13 (1999) 73 – 98) according to the OECD guidelines for 3,4,5,6-tetrachloro-2-(1,4,5,8-tetrabromo-6-hydroxy-3-oxoxanthen-9-yl)benzoic acid (Acid Red 92).

In the first validation, 100 ml aqueous solution or a suspension of the test substances (10%) was applied to the right eyes of male New Zealand white rabbits (2.30±2.98 kg, 13 wk of age). Left eyes remained untreated as a control. Eyes were observed at 1 hr, 4 hr, and every 24 hr thereafter for 7 days. Three rabbits were used for test. In the case of the second and the third validations, the concentrations were increased to 100% when the Draize score (maximum average total score: MAS) was lower than 20 or lowered to 1% or 0.1% when the MAS was higher than 20. Isotonic sodium chloride solution was also used as a negative control. The Maximum Average Score[MAS] obtained for 100% Acid Red 92 instilled in rabbits eyes is 71.0. According to the classification based on the MAS scores test chemical can be considered to be an eye irritant. It falls under the category - Eye Irritation 2 [CLP classification criteria].

 

Moreover in a study reported in COLIPA report (2004), the primary eye irritation potential of test chemical was investigated by instillation of 0.1 g into one eye of three young adult New Zealand White rabbits. Scoring of irritation effects was performed approximately 1, 24, 48 and 72 hours, as well as 7 and 10, 14 and 17 days after test item application.

The mean score was calculated across 3 scoring times (24, 48 and 72 hours after instillation) for each animal for corneal opacity, iris, redness and chemosis of the conjunctivae, separately.

The individual mean scores were as follows:

<Scornea opacity> = 0.0 - 0.0 - 1.0

<Siris> = 0.0 - 0.0 - 0.0

<Sconjunctiva redness> = 2.0 - 2.0 - 2.0

<Sconjunctiva chemosis> = 1.3 - 1.3 - 1.3

The instillation of the test item into the eye resulted in mild to moderate, early-onset and transient ocular changes, such as reddening of the conjunctivae and sclerae, discharge and chemosis. A slight corneal opacity, affecting up to the whole area of the cornea, was also apparent in one animal from 24 hours to 10 days after treatment, A light to marked red staining was also observed in the treated eye of all animals during the first 7 days after treatment. All ocular effects were reversible and were no longer evident 17 days after treatment. No abnormal findings were observed in the iris of any animal at any reading. No corrosion was observed at any of the measuring intervals.

The test item did not induce significant or irreversible damage to the rabbit eye. Based on the CLP classification criteria, the test item is considered to be not irritating to the eye.

 

Thus, according to CLP Regulation EC No. 1272/2008 and based on the studies of skin and eye irritation, it is concluded that the test chemical is ‘’not classified’’ as skin irritant but classified as an eye irritant in ‘’Category 2”.

Justification for classification or non-classification

According to CLP Regulation EC No. 1272/2008 and based on the studies of skin and eye irritation, it is concluded that the test chemical is ‘’not classified’’ as skin irritant but classified as an eye irritant in ‘’Category 2”.