1,1'-carbonylbis-1H-imidazole

Skin irritation / corrosion

Administrative data

Endpoint:

skin irritation: in vitro / ex vivo

Type of information:

other: data from hydrolysed substance

Adequacy of study:

key study

Study period:

1979

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study without detailed documentation

Justification for type of information:

Substance 530-62-1 hydrolyses

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1979

Report date:

1979

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 404 (Acute Dermal Irritation / Corrosion)

Deviations:

yes

Remarks:

however occlusive exposure instead of semi-occulsive

GLP compliance:

no

Test material

Test material information

Constituent 1

Reference substance name:

Imidazole

EC Number:

206-019-2

EC Name:

Imidazole

Cas Number:

288-32-4

Molecular formula:

C3H4N2

IUPAC Name:

1H-imidazole

Specific details on test material used for the study:

80%

In vitro test system

Vehicle:

not specified

Test animals

Species:

rabbit

Strain:

not specified

Test system

Type of coverage:

occlusive

Preparation of test site:

not specified

Vehicle:

water

Controls:

no

Duration of treatment / exposure:

1-4h

Observation period:

4h

Number of animals:

2 animals

Results and discussion

In vivo

Results

Irritation parameter:

erythema score

Basis:

mean

Time point:

7 d

Score:

2

Reversibility:

no data

Any other information on results incl. tables

Skin reactions after 1-hr exposure time:

Mild erythema was seen in all (4/4) animals 1 hr after removal of the occlusive dressing. Erythema subsided in one animal overnight. Focal necrosis developed in the other 3 animals within 24 and 48 hr. Findings at the end of the observation period (8 d) were as follows:

2/4 animals showed no erythema but showed desquamation (1/4) and focal necrosis (1/4). Slight erythema, desquamation and extended focal necrosis was seen in the 3rd animal, and severe erythema with superficial necrosis was noted in the 4th animal.

Oedema were absent after patch removal but grade 2 oedema were noted in 2/4 and 3/4 animals after 24 and 48 hr, respectively. Oedema had resolved on day 8 of observation.

Skin reactions after 4-hr exposure time:

Well defined, moderate erythema and oedema were seen in both animals after removal of the occlusive dressing. Erythema became severe overnight and rested severe until the end of the observation period. Soft necroses developed overnight in both animals. Leather-like necrosis indicative of full thickness necrosis was noted in both animals and confirmed by pathology after sacrifice of the animals. Oedema started to resolve overnight but rested as grade 2 until day 8.

General toxicity:

No signs noted after 1-hr or 4-hr exposure.

Applicant's summary and conclusion

Interpretation of results:

corrosive

Conclusions:

After 4-hr occlusive exposure moderate erythema and oedema were noted within 1 hr. Severe erythema developed overnight and persisted until day 8, the end of the observation period.
Soft necroses developed overnight. They hardened and changed into persistent leather-like necroses in both animals as noted on day 8. Slight oedema were noted at the end of the observation period.
No signs of general toxicity were noted.
Imidazole was corrosive.

Executive summary:

When 80 % Imidazole was applied to the intact rabbit skin as an aqueous paste for 1 or 4 hours under occlusive dressing skin reactions were noted as early as one hour after removal of the dressing. Focal necrosis developed overnight in all animals and was described as leather-like at the end of the observation period when pathology confirmed full thickness necrosis after sacrifice of the animals .