1,3-dihydro-5-methoxy-2H-benzimidazole-2-thione

Eye irritation

Administrative data

Endpoint:

eye irritation: in vivo

Type of information:

experimental study

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

comparable to guideline study with acceptable restrictions

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 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:

Benzimidazole-2-thiol

Details on test material:

SOURCE OF TEST MATERIAL
- Name of test material (as cited in study report): benzimidazole-2-thiol (2-MBI, 1,3-dihydrobenzimidazole-2-thione)
- Source and lot/batch No.of test material: Ouchi Shinko Chemical Ind., Ltd.(Osaka, Japan)
- Molecular formula (if other than submission substance): C7H6N2S
- Molecular weight (if other than submission substance):150.204 g/mole
- Substance type:organic

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

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 compound 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 compound 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.

Applicant's summary and conclusion

Interpretation of results:

other: not irritating

Conclusions:

Based on the results obtained from current Acute Eye Irritation study, it can be concluded that the test compound in the amount of 0.1gm was practically non irritant to the eyes of New Zealand white rabbit under test condition.

Executive summary:

The acute eye irritation study of test chemical was conducted in New Zealand White Rabbits as per the Guideline OECD- 405. Initial study of test chemical was conducted on one healthy rabbits of body weight 2.0kg. 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. The test compound when applied to conjunctival sac of rabbit in the amount of 0.1gm did not produce any eye irritation during the observation period. 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 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 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. Test compound applied to the conjunctival sac of the rabbits at the dose level of 0.1 gm did not produce any eye irritation as well as eye discharge. Furthermore, there was no other clinical sign recorded in both of the animals during the whole observation period for 21 days. Based on above findings, it can be concluded that the test compound was practically non-irritant when applied in the amount of 0.1 gm in the conjunctival sac of the rabbits