5H-1,2-oxathiole 2,2-dioxide

Eye irritation

Administrative data

Endpoint:

eye irritation: in vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2022

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2022

Report date:

2022

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 405 (Acute Eye Irritation / Corrosion)

Version / remarks:

adopted on 9 October 2017 (corrected on 14 June 2021)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

5H-1,2λ⁶-oxathiole-2,2-dione

EC Number:

606-834-7

Cas Number:

21806-61-1

Molecular formula:

C3H4O3S

IUPAC Name:

5H-1,2λ⁶-oxathiole-2,2-dione

Details on test material:

Physical appearance (with Color): white solid
Lot No.: N222070161
Molecular formula: C3H4O3S
Molecular weight: 120.12
Stability: Stable in room temperature
Date of Manufacture: 2022.7.1
Date of Expiry: 2023.6.30
Storage Conditions: Cool and dry (+2 to +8° C)
Test Item Code by Test Facility: D1547-001

Specific details on test material used for the study:

Physical appearance (with Color): white solid
Lot No.: N222070161
Molecular formula: C3H4O3S
Molecular weight: 120.12
Stability: Stable in room temperature
Date of Manufacture: 2022.7.1
Date of Expiry: 2023.6.30
Storage Conditions: Cool and dry (+2 to +8° C)

Test animals / tissue source

Species:

rabbit

Strain:

New Zealand White

Remarks:

Oryctolagus cuniculus

Details on test animals or tissues and environmental conditions:

No. of Animals / Test: Initial Test: 1 Female
Remaining two animals were sacrificed by overdose intravenous administration of sodium thiopentone.
(Females used were nulliparous and non-pregnant).
Age at Receipt: 5 months
Body Weight at Receipt: 2.18946 kg to 2.21835 kg
Animal Identification:
Acclimatization: Cage cards
Treatment Period: Cage cards and last 4 digits of the animal number was written on the ear of each rabbit using black permanent marker pen.
Animal No: Nc3720.
Husbandry
a. Environmental Conditions:
Animals were housed under standard laboratory conditions, in an environmentally monitored air-conditioned room with adequate fresh air supply (12 to 15 Air changes per hour), room temperature 19.2°C to 22.8°C and relative humidity 46% to 69% with 12 hours fluorescent light and 12 hours dark cycle. The temperature and relative humidity was recorded once daily.
b. Housing:
The animals were housed individually in stainless steel wire mesh cage (Size: L 24 x B 18 x H 18 inches) having facilities for holding pelleted feed and drinking water.
c. Feed:
Altromin Maintenance Diet for rabbits (manufactured by Altromin Spezialfutter GmbH & Co. KG) was provided ad libitum to the rabbits throughout the experimental period. The contaminant analysis test report for the feed is presented as Annexure 2.
d. Water:
Water was provided ad libitum throughout the acclimatization and experimental period. Deep bore-well water passed through reverse osmosis unit was provided in plastic water bottles with stainless steel sipper tubes.

Acclimatization:
Healthy young adult animals were acclimatized for a period of five days for initial test to the experimental room conditions prior to treatment and were observed for clinical signs once daily. Veterinary examination of all the animals was performed on the day of receipt.

Preparation of Animals:
Both the eyes of each experimental animal selected for testing were examined within 24 hours before initiating the treatment using ophthalmoscope. Only those animals with absence of signs of eye irritation, ocular defects or pre-existing corneal injury were used.

Test system

Vehicle:

unchanged (no vehicle)

Controls:

yes, concurrent no treatment

yes, concurrent negative control

Amount / concentration applied:

volume of 0.1 mL (94.8 mg) of pulverized test item was instilled to the initial test animal

Duration of treatment / exposure:

After pre-instillation procedure, test item was instilled into the conjunctival sac of the left eye by gently pulling the lower lid away from the eye ball. Then the eye lids were gently held together for a few second to prevent loss of test item. The right eye remained untreated and served as the control.
The eye was rinsed using 0.9% w/v normal saline after 1 hour of treatment (post treatment).

Observation period (in vivo):

21 days

Number of animals or in vitro replicates:

Initial Test: 1 Female
Remaining two animals were sacrificed by overdose intravenous administration of sodium thiopentone.
(Females used were nulliparous and non-pregnant).

Details on study design:

The experiment was performed in one phase that is initial test. As there was corrosive effect observed, confirmatory test was not conducted.

Results and discussion

In vivo

Results

Results 1

Irritation parameter:

cornea opacity score

Remarks:

Area of cornea involved: Score 4 ( at 24/48/72 h and Day 7/14/21, Max. score 4)

Basis:

mean

Remarks:

Animal No.: Nc3720

Time point:

24/48/72 h

Score:

2

Max. score:

4

Reversibility:

not reversible

Remarks on result:

positive indication of irritation

Results 2

Irritation parameter:

iris score

Basis:

mean

Remarks:

Animal No.: Nc3720

Time point:

24/48/72 h

Score:

0

Max. score:

2

Reversibility:

fully reversible

Results 3

Irritation parameter:

chemosis score

Basis:

mean

Remarks:

Animal No.: Nc3720

Time point:

24/48/72 h

Score:

1.67

Max. score:

4

Reversibility:

fully reversible

Results 4

Irritation parameter:

conjunctivae score

Basis:

mean

Remarks:

Animal No.: Nc3720

Time point:

24/48/72 h

Score:

2

Max. score:

3

Reversibility:

not reversible

Remarks on result:

positive indication of irritation

Irritant / corrosive response data:

Scoring of Ocular Lesions:
In initial test, treated eye (left) of revealed ocular lesions like redness (diffuse, crimson color; individual vessels not easily discernible) and chemosis (some swelling above normal) at 1st hour observation. At 24 and 48 hours observation, ocular lesions like redness (diffuse, crimson color; individual vessels not easily discernible), chemosis (obvious swelling, with partial eversion of lids), corneal opacity (easily discernible translucent area; details of iris slightly obscured) and area of opacity (greater than three-quarters, up to whole area). At 72 hours and on day 7 observation ocular lesions like redness (diffuse, crimson color; individual vessels not easily discernible), chemosis (some swelling above normal), corneal opacity (easily discernible translucent area; details of iris slightly obscured) and area of opacity (greater than three-quarters, up to whole area). On days 14 and 21 ocular lesions like redness (diffuse, crimson color; individual vessels not easily discernible), corneal opacity (easily discernible translucent area; details of iris slightly obscured) and area of opacity (greater than three-quarters, up to whole area) were observed.

Slit Lamp Examination:
In initial test, ocular lesions like conjunctivitis and corneal opacity were observed at 24, 48, 72 hours, on days 7 and 14 observation; conjunctivitis, corneal opacity and corneal ulceration/abrasion on day 21 observation during slit lamp examination.

Evaluation of Scoring:
For initial test, the mean score calculated across 3 scoring times (approximately 24, 48 and 72 hours after test item instillation) for corneal opacity, iris, conjunctival redness and conjunctival chemosis were 2, 0, 2 and 1.67 respectively.

Necropsy:
The initial test animal was sacrificed by intravenous administration of sodium thiopentone and subjected to Necropsy. The external gross pathological findings like Eye (left) - conjunctiva, discoloration, red - opacity, discharge, white were observed and there were no internal gross pathological changes.

Other effects:

Clinical Signs of Toxicity and Mortality:
No treatment related clinical signs of toxicity and mortality was observed in initial test animal.

Body Weight:
No treatment related changes were noted in body weight and percent change in body weight with respect to day 1 in initial test. Animal revealed physiologically normal increase in body weight.

Any other information on results incl. tables

• INDIVIDUAL ANIMAL EYE IRRITATION/CORROSION SCORING RECORD

Initial Test                         Sex: Female                        Dose: 0.1 mL/animal                Animal No.: Nc3720
Observation Period	Ocular Lesions
	Conjunctiva				Iris		Cornea
	Redness		Chemosis				Opacity		Area
Eyes	LE	RE	LE	RE	LE	RE	LE	RE	LE	RE
1 hr	2	0	1	0	0	0	0	0	-	-
24 hrs	2	0	2	0	0	0	2	0	4	-
48 hrs	2	0	2	0	0	0	2	0	4	-
72 hrs	2	0	1	0	0	0	2	0	4	-
Day 7	2	0	1	0	0	0	2	0	4	-
Day 14	2	0	0	0	0	0	2	0	4	-
Day 21	2	0	0	0	0	0	2	0	4	-
Mean Tissue Score	2	0	1.67	0	0	0	2	0	-	-

hr: hour; hrs: hours; LE: Left Eye (Treated Eye); RE: Right Eye (Untreated control Eye); -: Not applicable.

Mean Tissue Score = (24 hr+48 hr+72 hr)/3

 

Redness:  0: Normal; 2: Diffuse, crimson color; individual vessels not easily discernible.

Chemosis: 0: Normal; 1: Some swelling above normal; 2: obvious swelling, with partial eversion of lids.

Iris: 0: Normal.               

Opacity: 0: No ulceration or opacity; 2: Easily discernible translucent area; details of iris slightly obscured.

Area: 4: Greater than three-quarters, up to whole area.

 

• INDIVIDUAL ANIMAL SLIT LAMP EXAMINATION RECORD

Initial Test                  Sex: Female                        Dose: 0.1 mL/animal                           Animal No.: Nc3720

Day 2 (24 hours)

Day 3 (48 hours)

Day 4 (72 hours)

Day 7

Day 14

Day 21

Eye

LE

RE

LE

RE

LE

RE

LE

RE

LE

RE

LE

RE

Lids

13

N

13

N

13

N

13

N

13

N

13

N

Ducts

N

N

N

N

N

N

N

N

N

N

N

N

Cornea

24

N

24

N

24

N

24

N

24

N

24,16

N

Pupil

N

N

N

N

N

N

N

N

N

N

N

N

Sclera

N

N

N

N

N

N

N

N

N

N

N

N

Ciliary Bodies

N

N

N

N

N

N

N

N

N

N

N

N

Iris

N

N

N

N

N

N

N

N

N

N

N

N

Aqueous Humour

N

N

N

N

N

N

N

N

N

N

N

N

Lens

N

N

N

N

N

N

N

N

N

N

N

N

Vitreous Humour

N

N

N

N

N

N

N

N

N

N

N

N

  LE: Left Eye; RE: Right Eye; N: Normal/No Abnormality Detected; 13: Conjunctivitis; 24: Corneal Opacity; 16: Corneal ulceration/ abrasion.

 

• INDIVIDUAL ANIMAL GROSS PATHOLOGY FINDINGS

  

Phase of the Experiment	Dose (mL/animal)	Animal No.	Sex	Fate	Gross Pathology Findings
					External	Internal
Initial Test	0.1	Nc3720	Female	TS	Eye (Left) - Conjunctiva, discoloration, red, Opacity, discharge, white	NAD

TS: Terminal Sacrifice; NAD: No Abnormality Detected.

Applicant's summary and conclusion

Interpretation of results:

Category 1 (irreversible effects on the eye) based on GHS criteria

Conclusions:

Based on the above results of the experiment and under the experimental conditions employed, it is concluded that the mean score of test item, 5H-1,2-oxathiole 2,2-dioxide is classified as “Category 1 (Serious eye damage / Irreversible effects on eye)” as per the Globally Harmonized System of Classification and Labelling of Chemicals (GHS).

Executive summary:

The test item, 5H-1,2-oxathiole 2,2-dioxide was evaluated for In Vivo Eye Irritation/ Serious Eye Damage in New Zealand White Rabbits.
Both the eyes of each experimental animal were examined within 24 hours before the treatment. The animals with absence of signs of eye irritation, ocular defects or pre-existing corneal injury were used for the treatment. The pH of test item was 5.30 as per in-house pH determination.
The initial test was conducted using single female rabbit, as there was corrosive effect observed, confirmatory test was not conducted. The systemic analgesic tramadol hydrochloride injection (2.5 mg/kg) and two drops of topical ocular anesthetic (0.5% tetracaine hydrochloride) were given to the animal at sixty minutes and five minutes prior to test item instillation respectively. The 0.1 mL (94.8 mg) of test item was instilled into the conjunctival sac of the left eye and right eye served as control. The eyes were scored approximately at 1, 24, 48, 72 hours, on days 7, 14 and 21. Slit lamp examination was carried out using fluorescein strips (fluorescein sodium ophthalmic strip USP) and were scored approximately at 24, 48, 72 hours, on days 7, 14 and 21.
The initial test animal was observed twice daily for clinical signs of toxicity and mortality. No treatment related clinical signs of toxicity and mortality were observed in initial test animal after the test item instillation.
In initial test, treated eye (left) revealed ocular lesions like redness and chemosis at 1st hour observation; Redness, chemosis and corneal opacity at 24, 48, 72 hours and on day 7 observation; Redness and corneal opacity on days 14 and 21 observation.
In initial test, ocular lesions like conjunctivitis and corneal opacity were observed at 24, 48, 72 hours, on days 7 and 14 observation; conjunctivitis, corneal opacity and corneal ulceration/abrasion on day 21 observation during slit lamp examination.
The body weights were recorded on the day of receipt, on the day of treatment (prior to instillation of test item) and weekly thereafter of the experiment. No treatment related changes were noted in body weight and percent change in body weight with respect to day 1. Animal revealed physiologically normal increase in body weight in initial test.
At termination, the initial test animal was sacrificed by intravenous administration of sodium thiopentone and subjected to Necropsy. The external gross pathological findings like Eye (left) - conjunctiva, discoloration, red - opacity, discharge, white were observed and there were no internal gross pathological changes. Remaining two animals were sacrificed by overdose intravenous administration of sodium thiopentone and carcass were disposed.
In initial test animal, the mean score calculated across 3 scoring times (approximately 24, 48 and 72 hours after test item instillation) for corneal opacity, iris, conjunctival redness and conjunctival chemosis were 2, 0, 2 and 1.67 respectively.

Based on the above results of the experiment and under the experimental conditions employed, it is concluded that the mean score of test item, 5H-1,2-oxathiole 2,2-dioxide is classified as “Category 1 (Serious eye damage / Irreversible effects on eye)”.