5,5'-{ethane-1,2-diylbis[thio-1,3,4-thiadiazole-5,2-diyldiazene-2,1-diyl(5-amino-3-tert-butyl-1H-pyrazole-4,1-diyl)]}diisophthalic acid

Eye irritation

Administrative data

Endpoint:

eye irritation: in vivo

Remarks:

in vivo, existing study

Type of information:

experimental study

Adequacy of study:

key study

Study period:

The study was performed between 18 July 2011 and 07 September 2011

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: see 'Remark'

Remarks:

Study conducted in compliance with agreed protocols, with no or minor deviations from standard test guidelines and/or minor methodological deficiencies, which do not affect the quality of the relevant results. The study report was conclusive, done to a valid guideline and the study was conducted under GLP conditions.

Justification for type of information:

1. HYPOTHESIS FOR THE ANALOGUE APPROACH
The read-across is based on the hypothesis that the Source and Target substances will have similar toxicological and ecotoxicological properties, due to their extremely close physico-chemical properties and structural similarities. For example, both the Source and Target substances are mono-constituents which share structural similarities and contain the same functional groups.
The Source substance has a comprehensive data set generated for a REACH Annex VII registration and this along with its similarity to the Target substance are considered sufficient to consider the read-across an appropriate adaptation to the standard information requirements of Annex VII of the REACH regulation for the Target substance in accordance with the provisions of Annex XI, 1.5 of the REACH regulation.
As can be seen from the structure the Source substance and the Target substance are structurally identical the difference lies in the salt form i.e. the counter ion. In the case of the Source substance the counter ion is a potassium ion whereas in the Target substance the counter ion is a hydrogen .
SOURCE TARGET
mono-constituent substance mono-constituent substance

Potassium salt
Free acid


Both the Source and Target substances have similar molecular weights of 1073 and 921 respectively. The difference in molecular weight is due to the counter ions. The Source substance is the potassium salt of the Target substance.


2. SOURCE AND TARGET CHEMICAL(S) (INCLUDING INFORMATION ON PURITY AND IMPURITIES)

The Source and Target substance have similar purity profiles. Water is the main impurity in both substances. Both substances contain impurities that are analogues of the Source molecule. Neither substance contains purposely added diluents or additives.
The Source and Target are manufactured using the same chemical synthetic route. The difference in salt form is the difference between the two substances.

3. ANALOGUE APPROACH JUSTIFICATION
The Target substance is the free acid salt of the Source substance, hence the Target contains all the same functional groups as the Source substance. It is anticipated that the physicochemical results of the Target and the Source substance will be very similar.
It is expected that the water solubility of the Target Substance will be slightly lower than the Source substance, although environmental conditions will impact on the degree of solubility. Even though the water solubility values are differ , both the Source and Target substance are extremely water soluble and neither will have a tendency to partition into lipids or body fats. The potential for systemic absorption is considered to be low for both substances as their bioavailability is expected to be low due to the high molecular weights of the molecules and low lipophilicity, which precludes easy passage across biological membranes.
For the full read across assessment dossier see the attached Read-across assessment framework report


4. DATA MATRIX
See Read-Across Assessment Framework Report

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2011

Report date:

2011

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 405 (Acute Eye Irritation / Corrosion)

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method B.5 (Acute Toxicity: Eye Irritation / Corrosion)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

Tetra potassium 5,5'-[ethane-1,2-diylbis[thio-1,3,4-thiadiazole-5,2-diyldiazene-2,1-diyl(5-amino-3-tert-buyl-1H-pyrazole-4,1-diyl)]}diisophthalate

EC Number:

700-616-6

Cas Number:

849608-59-9

Molecular formula:

C36H32K4N14O8S4

IUPAC Name:

Tetra potassium 5,5'-[ethane-1,2-diylbis[thio-1,3,4-thiadiazole-5,2-diyldiazene-2,1-diyl(5-amino-3-tert-buyl-1H-pyrazole-4,1-diyl)]}diisophthalate

Test material form:

solid

Test animals / tissue source

Species:

rabbit

Strain:

New Zealand White

Details on test animals or tissues and environmental conditions:

Three New Zealand White (Hsdlf:NZW) strain rabbits were supplied by Harlan Laboratories UK Ltd., Leicestershire, UK. At the start of the study the animals weighed 2.38 to 3.04 kg and were twelve to twenty weeks old. After an acclimatisation period of at least five days each animal was given a number unique within the study which was written with a black indelible marker-pen on the inner surface of the ear and on the cage label.
The animals were individually housed in suspended cages. Free access to mains drinking water and food (2930 Teklad Global Certified Rabbit diet supplied by Harlan Laboratories UK Ltd., Oxon, UK) was allowed throughout the study. The diet and drinking water were considered not to contain any contaminant of a level that might have affected the purpose or integrity of the study.
The temperature and relative humidity were set to achieve limits of 17 to 23°C and 30 to 70% respectively. Any occasional deviations from these targets were considered not to have affected the purpose or integrity of the study. The rate of air exchange was at least fifteen changes per hour and the lighting was controlled by a time switch to give twelve hours continuous light (06:00 to 18:00) and twelve hours darkness.
The animals were provided with environmental enrichment items which were considered not to contain any contaminant of a level that might have affected the purpose or integrity of the study.

Test system

Vehicle:

unchanged (no vehicle)

Controls:

other: The left eye remained untreated and was used for control purpose.

Amount / concentration applied:

TEST MATERIAL

- Amount(s) applied (volume or weight with unit):
A volume of 0.1 ml of the test material was placed into the conjunctival sac of the right eye, formed by gently pulling the lower lid away from the eyeball.

- Concentration (if solution):
Ground before use

VEHICLE

- Amount(s) applied (volume or weight with unit):
Not applicable

- Concentration (if solution):
Not applicable

- Lot/batch no. (if required):
Not applicable

- Purity:
Not reported

Duration of treatment / exposure:

1 hour

Observation period (in vivo):

Approximately 1 hour and 24, 48 and 72 hours following treatment

Number of animals or in vitro replicates:

3 animals were tested in total. (After consideration of the ocular responses produced in the first treated animal, two additional animals were treated. )

Details on study design:

Immediately before the start of the test, both eyes of the provisionally selected test rabbits were examined for evidence of ocular irritation or defect with the aid of a light source from a standard ophthalmoscope. Only animals free of ocular damage were used.
Initially, a single rabbit was treated. A volume of 0.1 ml of the test item, which was found to weigh approximately 74 mg (as measured by gently compacting the required volume into an adapted syringe) was placed into the conjunctival sac of the right eye, formed by gently pulling the lower lid away from the eyeball. The upper and lower eyelids were held together for about one second immediately after treatment, to prevent loss of the test item, and then released. The left eye remained untreated and was used for control purposes. Immediately after administration of the test item, an assessment of the initial pain reaction was made according to the six point scale shown in Appendix 1.

After consideration of the ocular responses produced in the first treated animal, two additional animals were treated.
Assessment of ocular damage/irritation was made approximately 1 hour and 24, 48 and 72 hours following treatment, according to the numerical evaluation given in Appendix 2, (from Draize J H (1977) "Dermal and Eye Toxicity Tests" In: Principles and Procedures for Evaluating the Toxicity of Household Substances, National Academy of Sciences, Washington DC p.48 to 49).
Any other ocular effects were also noted. Examination of the eye was facilitated by the use of the light source from a standard ophthalmoscope.

Any clinical signs of toxicity, if present, were also recorded.
Additional observations were made on Days 7 and 14 to assess the reversibility of the ocular effects.
Individual bodyweights were recorded on Day 0 (the day of dosing) and at the end of the observation period.

Results and discussion

In vivo

Results

Results 1

Irritation parameter:

cornea opacity score

Basis:

animal: 70738 Male

Time point:

other: Highest score at 24, 48 and 72 hours

Score:

1

Max. score:

4

Reversibility:

fully reversible within: 7 days

Results 2

Irritation parameter:

cornea opacity score

Basis:

animal: 70807 Male

Time point:

other: Highest score at 24, 48 and 72 hours

Score:

1

Max. score:

4

Reversibility:

fully reversible within: 72 hours

Results 3

Irritation parameter:

cornea opacity score

Basis:

animal: 70881 Male

Time point:

other: Highest score at 24, 48 and 72 hours

Score:

0

Max. score:

4

Reversibility:

fully reversible within: 7 days

Results 4

Irritation parameter:

iris score

Basis:

animal: 70738 Male

Time point:

other: Highest score at 24, 48 and 72 hours

Score:

1

Max. score:

2

Reversibility:

fully reversible within: 7 days

Results 5

Irritation parameter:

iris score

Basis:

animal: 70807 Male

Time point:

other: Highest score at 24, 48 and 72 hours

Score:

1

Max. score:

2

Reversibility:

fully reversible within: 72 hours

Results 6

Irritation parameter:

iris score

Basis:

animal: 70881 Male

Time point:

other: Highest score at 24, 48 and 72 hours

Score:

1

Max. score:

2

Reversibility:

fully reversible within: 7 days

Results 7

Irritation parameter:

other: redness

Basis:

animal: 70738 Male

Time point:

other: Higest score at 24, 48 and 72 hours

Score:

2

Max. score:

3

Reversibility:

fully reversible within: 14 days

Remarks on result:

other: Orange coloured staining of fur around the eye

Results 8

Irritation parameter:

other: redness

Basis:

animal: 70807 Male

Time point:

other: Highest scote at 24, 48 and 72 hours

Score:

2

Max. score:

3

Reversibility:

fully reversible within: 14 days

Remarks on result:

other: Orange coloured staining of fur around the eye

Results 9

Irritation parameter:

other: redness

Basis:

animal: 70881 Male

Time point:

other: Highest score at 24, 48 and 72 hours

Score:

2

Max. score:

3

Reversibility:

fully reversible within: 14 days

Remarks on result:

other: Orange coloured staining of fur around the eye

Results 10

Irritation parameter:

chemosis score

Basis:

animal: 70738 Male

Time point:

other: Highest score at 24, 48 and 72

Score:

2

Max. score:

4

Reversibility:

fully reversible within: 48 hours

Results 11

Irritation parameter:

chemosis score

Basis:

animal: 70807 Male

Time point:

other: Highest score 24, 48 and 72 hours

Score:

2

Max. score:

4

Reversibility:

fully reversible within: 7 days

Results 12

Irritation parameter:

chemosis score

Basis:

animal: 70881 Male

Time point:

other: Highest score at 24, 48 and 72 hours

Score:

2

Max. score:

4

Reversibility:

fully reversible within: 14 days

Irritant / corrosive response data:

Ocular Reactions
Individual and group mean scores for ocular irritation are given in Table 1 and Table 2 (see "Any other information on results incl. tables" section).
Orange coloured staining of the fur was noted around all treated eyes during the study.
Scattered or diffuse corneal opacity was noted in all treated eyes one hour after treatment and at the 24 and 48 Hour observations and persisted in two treated eyes at the 72 Hour observation.
Iridial inflammation was noted in all treated eyes one hour after treatment and at the 24 and 48 Hour observations and persisted in two treated eyes at the 72 Hour observation.
Moderate conjunctival irritation was noted in all treated eyes one hour after treatment and at the 24, 48 and 72 Hour observations with minimal conjunctival irritation noted at the 7 Day observation.
All treated eyes appeared normal at the 14 Day observation.

Other effects:

Bodyweight
Individual bodyweights and bodyweight changes are given in Table 3 (see "Any other information on results incl. tables" section)
All animals showed expected gain in bodyweight during the study.

Any other information on results incl. tables

Interpretation of Results

The numerical values corresponding to each animal, tissue and observation time were recorded. The data relating to the conjunctivae were designated by the letters A (redness), B (chemosis) and C (discharge), those relating to the iris designated by the letter D and those relating to the cornea by the letters E (degree of opacity) and F (area of cornea involved). For each tissue the score was calculated as follows:

Score for conjunctivae =         (A + B + C) x 2
Score for iris                            =         D x 5
Score for cornea                      =         (E x F) x 5

Using the numerical data obtained a modified version of the system ( Modified Kay and Calandra Interpretation of Eye Irritation Test was used to classify the ocular irritancy potential of the test material. This was achieved by adding together the scores for the cornea, iris and conjunctivae for each time point for each rabbit. The group means of the total scores for each observation were calculated. The highest of these group means (the maximum group mean score) together with the persistence of the reactions enabled classification of the eye irritancy potential of the test material.

If evidence of irreversible ocular damage is noted, the test material will be classified as corrosive to the eye.

The results were evaluated according to EU labelling regulations Commission Directive 2001/59/EC and Regulation (EC) No 1272/2008 for classification and labelling of dangerous substances.

Table 1              Individual Scores and Individual Total Scores for Ocular Irritation

Rabbit Number and Sex	70738Male						70807Male						70881Male
	IPR= 2						IPR = 2						IPR = 2
Time After Treatment	1 Hour	24 Hours	48 Hours	72 Hours	7 Days	14 Days	1 Hour	24 Hours	48 Hours	72 Hours	7 Days	14 Days	1 Hour	24 Hours	48 Hours	72 Hours	7 Days	14 Days
CORNEA
E = Degree of Opacity	1	1	1	1	0	0	1	1	1	0	0	0	1	1	1	1	0	0
F = Area of Cornea Involved	2	2	2	1	0	0	2	1	1	0	0	0	1	1	1	1	0	0
Score (E x F) x 5	10	10	10	5	0	0	10	5	5	0	0	0	5	5	5	5	0	0
IRIS
D	1	1	1	1	0	0	1	1	1	0	0	0	1	1	1	1	0	0
Score (D x 5)	5	5	5	5	0	0	5	5	5	0	0	0	5	5	5	5	0	0
CONJUNCTIVAE
A = Redness	2Sf	2Sf	2Sf	2Sf	1Sf	0Sf	2Sf	2Sf	2Sf	2Sf	1Sf	0	2Sf	2Sf	2Sf	2Sf	1	0
B = Chemosis	2	2	2	2	1	0	2	1	1	1	0	0	2	1	1	1	1	0
C = Discharge	2	2	1	1	0	0	2	2	1	1	0	0	2	2	1	1	0	0
Score (A + B + C) x 2	12	12	10	10	4	0	12	10	8	8	2	0	12	10	8	8	4	0
Total Score	27	27	25	20	4	0	27	20	18	8	2	0	22	20	18	18	4	0

IPR=  Initial pain reaction

Sf=    Orangecoloured staining of fur around the eye

Table 2              Individual Total Scores and Group Mean Scores for Ocular Irritation

Rabbit Number and Sex	Individual Total Scores At:
	1 Hour	24 Hours	48 Hours	72 Hours	7 Days	14 Days
70738Male	27	27	25	20	4	0
70807Male	27	20	18	8	2	0
70881Male	22	20	18	18	4	0
Group Total	76	67	61	46	10	0
Group Mean Score	25.3	22.3	20.3	15.3	3.3	0.0

Table 3              Individual Bodyweights and Bodyweight Changes

Rabbit Number and Sex	Individual Bodyweight (kg)		Bodyweight Change (kg)
	Day 0	Day 14
70738Male	2.54	2.93	0.39
70807Male	2.38	2.69	0.31
70881Male	3.04	3.36	0.32

Applicant's summary and conclusion

Interpretation of results:

Category 2 (irritating to eyes) based on GHS criteria

Conclusions:

The test item produced a maximum group mean score of 25.3 and was classified as a moderate irritant (Class 5 on a 1 to 8 scale) to the rabbit eye according to a modified Kay and Calandra classification system.
The test item was classified as irritant according to EU labelling regulations Commission Directive 2001/59/EC. The symbol “Xi”, the indication of danger “Irritant” and the risk phrase R 36 “IRRITATING TO EYES” are therefore required.
The test item was also classified as Irritating to eyes (Category 2) according to Regulation (EC) No 1272/2008.

Executive summary:

Introduction. 

The study was performed to assess the irritancy potential of the test item to the eye of the New Zealand White rabbit. The method was designed tobe compatible with the following:

OECD Guidelines for the Testing of Chemicals No. 405 “Acute Eye Irritation/Corrosion” (adopted24 April 2002)

Method B5 Acute Toxicity (Eye Irritation) of Commission Regulation (EC) No. 440/2008

Result. 

A single application of the test item to the non-irrigated eye of three rabbits produced scattered or diffuse corneal opacity, iridial inflammation and moderate conjunctival irritation. All treated eyes appeared normal at the 14-Day observation.

Conclusion. 

The test item produced a maximum group mean score of 25.3 and was classified as amoderate irritant (Class 5 on a 1 to 8 scale) to the rabbit eye according to a modified Kay and Calandra classification system.

The test item was classified as irritant according to EU labelling regulations Commission Directive 2001/59/EC. The symbol “Xi”, the indication of danger “Irritant” and the risk phrase R 36 “IRRITATING TO EYES” are therefore required.

The test item was also classified as Irritating to eyes (Category 2) according to Regulation (EC) No 1272/2008.