Registration Dossier

Administrative data

Description of key information

In 2 limited studies Vulkanox MB2 (methyl-2-mercaptobenzimidazole) was tested for skin irritation/corrosion and eye irritation. The test substance was found to be not irritating to the skin and not irritating to the eye. Although the eye irritation test is limited with respect to dose (50 mg instead of 100 mg), due to the absence of any effect the study is reliable.
Additionally, a sin irritation/corrosion study and an eye irritation study with 1,3-dihydro-4(or 5)-methyl-2H-benzimidazole-2-thione, zinc salt (CAS 61617-00-3) as a surrogate for 1,3-dihydro-4(or 5)-methyl-2H-benzimidazole-2-thione (CAS 53988-10-6) were also negative.

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:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: sufficient documented and scientifically acceptable
Reason / purpose:
reference to same study
Principles of method if other than guideline:
500 mg of the test substance were semi-occlusively applied once to the intact skin onto the inside of the ear of one male and one female young adult New Zealand White rabbit (3-4 kg) for an exposure period of 24 hours. Evaluation of skin irritation was made until day 7 according to Draize et al. (J.Pharmacol. Exp. Ther. 82, 377-390 (1944).
GLP compliance:
no
Species:
rabbit
Strain:
New Zealand White
Type of coverage:
semiocclusive
Preparation of test site:
other: application at the inside of the ear
Vehicle:
unchanged (no vehicle)
Controls:
not required
Duration of treatment / exposure:
24 hours
Observation period:
7 days
Number of animals:
2 animals
Irritation parameter:
primary dermal irritation index (PDII)
Basis:
animal #1
Time point:
other: 1 h, 24 h, 4 d, 5 d, 6 d, 7 d
Score:
0
Max. score:
8
Reversibility:
other: not applicable - score = 0 at any time point
Irritation parameter:
primary dermal irritation index (PDII)
Basis:
animal #2
Time point:
other: 1 h, 24 h, 2 d, 3 d, 6 d, 7 d
Score:
0
Max. score:
8
Reversibility:
other: not applicable - score = 0 at any time point
Other effects:
no data

The test substance proved to be not irritating to the skin

Interpretation of results:
not irritating
Remarks:
Migrated information
Executive summary:
500 mg of the test substance were semi-occlusively applied once to the intact skin onto the insideof the ear of one male and one female young adult New Zealand White rabbit(3-4 kg) for an exposureperiod of 24 hours. Evaluation of skin irritation was made until day 7 according to Draize et al.(J.Pharmacol. Exp. Ther. 82, 377-390 (1944). The test substance proved to be not irritating to the skin.
Endpoint conclusion
Endpoint conclusion:
no adverse effect observed (not irritating)

Eye irritation

Link to relevant study records
Reference
Endpoint:
eye irritation: in vivo
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: sufficient documented and scientifically acceptable
Principles of method if other than guideline:
A dose of 50 mg of the test substance was administered into one eye of one male and one female adult New Zealand White rabbit (3-4 kg) for an exposure period of 24 hours. Then the treated eyes were rinsed with sterile water. The contralateral eye remained untreated and served as a control. The eyes were examined and the grade of the ocular reaction was recorded until day 7 according to Draize et al. (J. Pharmacol. Exp. Ther. 82, 377-390 (1944)).
GLP compliance:
no
Species:
rabbit
Strain:
New Zealand White
Vehicle:
unchanged (no vehicle)
Controls:
not required
Duration of treatment / exposure:
1 day
Observation period (in vivo):
7 days
Number of animals or in vitro replicates:
2 animals
Irritation parameter:
overall irritation score
Basis:
mean
Time point:
other: 1 h, 24 h, 2 d, 3 d, 6 d, 7 d
Score:
0
Max. score:
13
Reversibility:
other: not applicable - score = 0 at any time point
Other effects:
at the inspection 1 h after the application of the test substance for 24 hours a slight redness of the treated eye (score = 1) was found. This finding was reversible within 24 h (score = 0).

The test substance proved to be not irritating to the eye

Interpretation of results:
not irritating
Remarks:
Migrated information
Executive summary:

A dose of 50 mg of the test substance was administered into one eye of one male and one female adult New Zealand White rabbit (3-4 kg) for an exposure period of 24 hours. Then the treated eyes were rinsed with sterile water. The contralateral eye remained untreated and served as a control. The eyes were examined and the grade of the ocular reaction was recorded until day 7 according to Draize et al. (J. Pharmacol. Exp. Ther. 82, 377-390 (1944)).

The test substance was not irritating to the eye (score = 0 at any time point).

Endpoint conclusion
Endpoint conclusion:
no adverse effect observed (not irritating)

Respiratory irritation

Endpoint conclusion
Endpoint conclusion:
no study available

Additional information

The test substance was tested in a 24 h skin irritation/corrosion test in rabbits not conducted according actual guidelines. The test substance (500 mg) was semi-occlusively applied once to the intact skin (inside a rabbit ear) and remained there for 24 hours. The animals were observed for 7 days after experiment. Mean value for erythema according to DRAIZE was: 0.0; mean value for edema: 0.0. The test substance was found to be not irritating.

The test substance was tested in a 24 h eye irritation test in rabbits. The test substance (50 mgl) was administered into one eye of 2 rabbits (the other eye remained untreated and served as control). The substance was washed out after 24 hours with sterile water.

The animals were observed for 7 days after experiment.

The test substance was found to be not irritating to eye.


Justification for selection of skin irritation / corrosion endpoint:
key study used

Justification for selection of eye irritation endpoint:
key study used

Justification for classification or non-classification

skin irritation:

mean value for erythema = 0, mean value for edema = 0

On the basis of this data a classification is not justified

eye irritation:

mean values for cornea opacity (0); mean values for iris inflammation (0);

mean values for conjunctivae reddening (0), mean values for conjunctivae swelling (0)

On the basis of this data a classification is not justified