Benzimidazole-2-thiol

Eye irritation

Administrative data

Endpoint:

eye 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 study report.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2013

Report date:

2013

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 405 (Acute Eye Irritation / Corrosion)

Principles of method if other than guideline:

The study was conducted to evaluate the acute eye irritation index of the test chemical in New Zealand White rabbits.

GLP compliance:

no

Test material

Test material information

Constituent 1

Reference substance name:

Benzimidazole-2-thiol

EC Number:

209-502-6

EC Name:

Benzimidazole-2-thiol

Cas Number:

583-39-1

Molecular formula:

C7H6N2S

IUPAC Name:

1H-benzimidazole-2-thiol

Details on test material:

SOURCE OF TEST MATERIAL
- Test substance: 2-mercaptobenzimidazole (benzimidazole-2-thiol) (CAS No. 583-39-1) is a pale yellow white powder with a molecular weight of 150.21.
- Source of test material: Sumitomo Chemical Co., Ltd.
- Lot number: 30807
- Purity: 98.5%
- Substance type: Organic
- Physical state: Solid
- Molecular formula: C7H6N2S
- Molecular weight: 150.204 g/mol

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: The test substance was kept at room temperature with light shielding until use.
- Stability under test conditions: No data
- Solubility and stability of the test substance in the solvent/vehicle: Stability tests of 2-mercaptobenzimidazole in DMSO solution were carried out at low concentration (3.125 mg / ml) in this study and high concentration (300 mg / ml) in chromosomal aberration test conducted simultaneously in our laboratory 2 concentration under light-shielded condition at room temperature. As a result, the average content of each 3 samples after preparation for 4 hours was 99.7 and 108% with respect to the average of the initial value (0 hour), respectively. In addition, as a result of conducting the content measurement test on the prepared specimens used in this Test I, the content of the 3.125 mg / ml solution was 96.2 to 97.1% with respect to the predetermined concentration, the content of the 50 mg / ml solution was 95.4 to 96.2% there were.
From the above results, it was confirmed that the 2-mercaptobenzimidazole was stable in the DMSO solution and the content of the test substance in the preparation solution was within the predetermined value range.
- 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: 2-Mercaptobenzimidazole was prepared by adjusting the concentration to 50 mg / ml in dimethylsulfoxide (hereinafter abbreviated as DMSO, Wako Pure Chemical Industries, Ltd.), then further diluting it with the same solvent at a common ratio of 2 to about 3 was used for the test promptly.

Test animals / tissue source

Species:

rabbit

Strain:

New Zealand White

Details on test animals or tissues and environmental conditions:

Details on test animals
- Age at study initiation: 10 to 12 weeks
- Weight at study initiation: 2.0kg ±200g
- Housing: Rabbit was housed in stainless steel cages provided with stainless steel mesh bottom and facilities for food and water bottle.
- Diet (e.g. ad libitum):Pelleted feed supplied ad libitum
- Water (e.g. ad libitum): Community tap water passed through ‘Aqua Guard on line water filter’ was kept in bottles, ad libitum.
- Acclimation period: The rabbit was acclimatized to standard laboratory condition for 24 hours in experimental room before study.

ENVIRONMENTAL CONDITIONS
- Temperature (°C):22-25 degC
- Humidity (%):40-60%
- Air changes (per hr):10-15 air changes per hour
- Photoperiod (hrs dark / hrs light): illumination cycle set to 12 hours artificial fluorescent light and 12 hours dark.

Test system

Vehicle:

unchanged (no vehicle)

Controls:

yes, concurrent no treatment

Amount / concentration applied:

TEST MATERIAL
- Amount(s) applied (volume or weight with unit): 0.1 gm

Duration of treatment / exposure:

21 days

Observation period (in vivo):

1, 24, 48 and 72 hours.
To determine the reversibility of the effect the animal was observed normally for 21 days.

Number of animals or in vitro replicates:

Three female rabbits

Details on study design:

REMOVAL OF TEST SUBSTANCE
- Washing (if done):after 24 hrs.

SCORING SYSTEM: Draize

TOOL USED TO ASSESS SCORE: Biomicroscope and hand slit lamp further examined with the aid of fluorescein.

Results and discussion

In vivo

Results

Results 1

Irritation parameter:

overall irritation score

Basis:

mean

Time point:

24/48/72 h

Score:

0

Reversibility:

not specified

Remarks on result:

no indication of irritation

Results 2

Irritation parameter:

overall irritation score

Basis:

mean

Time point:

21 d

Score:

0

Reversibility:

not specified

Remarks on result:

no indication of irritation

Irritant / corrosive response data:

The test chemical when applied to the eye of New Zealand white rabbit at the dose level of 0.1 gm did not produce any eye irritation. Furthermore, any lesions such as pannus, staining were not recorded throughout the observation period of 72 hours.

Other effects:

Clinical Signs: The test chemical applied in conjunctival sac of rabbits at the dose level of 0.1 gm did not show any observable clinical signs such as cage side activity and pain or stress etc. throughout the observation period of 21 days.

Any other information on results incl. tables

GRADING OF OCULAR LESIONS

 

S.NO/ SEX		OBSERVATION	Score				Total	Total Score
1/F			1 hour	24hours	48 hours	72 hours
	Cornea	A.       Opacity-Degree of Density	0	0	0	0	0	0×0×5=0
		B.       Area of Cornea Involved	0	0	0	0	0
	Iris	A.       Values	0	0	0	0	0	0
	Conjunctivae	A.       Redness	0	0	0	0	0	0+0+0×5=0
		B.       Chemosis	0	0	0	0	0
		C.       Discharge	0	0	0	0	0
2/F	Cornea	A.       Opacity-Degree of Density	0	0	0	0	0	0×0×5=0
		B.       Area of Cornea Involved	0	0	0	0	0
	Iris	A.       Values	0	0	0	0	0	0
	Conjunctivae	A.       Redness	0	0	0	0	0	0+0+0×5=0
		B.       Chemosis	0	0	0	0	0
		C.       Discharge	0	0	0	0	0
3/F	Cornea	A.       Opacity-Degree of Density	0	0	0	0	0	0×0×5=0
		B.       Area of Cornea Involved	0	0	0	0	0
	Iris	A.       Values	0	0	0	0	0	0
	Conjunctivae	A.       Redness	0	0	0	0	0	0+0+0×5=0
		B.       Chemosis	0	0	0	0	0
		C.       Discharge	0	0	0	0	0
Grand total								0.00
Mean								0.00
Eye Irritation Scoring index								0.00

 

Applicant's summary and conclusion

Interpretation of results:

other: not irritating

Conclusions:

The test chemical when applied to the eye of New Zealand white rabbit at the dose level of 0.1 gm did not produce any eye irritation. Furthermore, any lesions such as pannus, staining were not recorded throughout the observation period of 72 hours.

Executive summary:

The acute eye irritation study of the test chemical was conducted in New Zealand White Rabbits as per the Guideline OECD- 405.

One healthy rabbits of body weight 2.0kg was selected for study after acclimatization. Both eyes of rabbits were examined for any abnormal disch arge such as eye irritation, ocular defects or pre-existing corneal injury from eye 24 hours prior to application of test compound. Test chemical was applied in the conjunctival sac of rabbit after gently pulling the lower lid away from the eyeball at the dose rate of 0.1gm.The lids were then gently held for about one second in order to prevent loss of the material. The other eye which remain untreated, served as a control. The acute irritation to eye conjunctiva, cornea and iris was evaluated at 1, 24, 48 and 72 hours after the treatment. The grades of ocular reaction (conjunctiva, cornea and iris) were recorded at each observation. To determine the reversibility of the effect the animal was observed normally for 21 days. Any other lesions in the eye viz pannus, staining were observed and scored accordingly. Examination of reactions was facilitated by use of biomicroscope and hand slit lamp. Individual animal weight before and during the study was observed.

The test chemical failed to produce any eye irritation during the observation period in the initial test . Furthermore, no other clinical signs were recorded after application of test compound such as cage side activity, pain etc. The result obtained from the initial test was confirmed in additional two animals of same sex and same dose level (OECD-405).

Test compound was applied in the amount of 0.1 gm in the conjunctival sac of each rabbit after gently pulling the lower lid away from the eyeball.The other eye which remain untreated, served as a control. The acute irritation to eye conjunctiva, cornea and iris was evaluated at 1, 24, 48 and 72 hoursafter the treatment. The grades of ocular reaction (conjunctiva, cornea and iris) were recorded at each observation. To determine the reversibility of the effect the animals were observed normally for 21 days. Any other lesions in the eye viz pannus, staining were observed and scored accordingly. Examination of reactions was facilitated by use of biomicroscope and hand slit lamp. The test chemical when applied to the eye of New Zealand white rabbit at the dose level of 0.1 gm did not produce any eye irritation. Furthermore, any lesions such as pannus, staining were not recorded throughout the observation period of 72 hours.