1,2-dimethylimidazole

Endpoint summary

Description of key information

In one study slight erythema and edema after an exposure of 20 hours to 1, 2-dimethylimidazole was observed. No signs of erythema nor edema were observed after an exposure of 1, 5 or 15 minutes. In another study, after 1 and 4 hours exposure, slight to strong erythema and edema as well as superficial necrosis and parchment-like skin developed which remained throughout the 8-day observation period.
Application of the test substance to the eyes led to a conjunctivea score of 2, a cornea score of 2 and a chemosis score of 1. After 8 days, scarring of the eyelids was observed. These effects were not reversible within 8 days.

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:

comparable to guideline study with acceptable restrictions

Remarks:

Meets generally accepted scientific standards, well documented and acceptable for assessment.

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 404 (Acute Dermal Irritation / Corrosion)

Version / remarks:

prior to the adoption of OECD404 in 1981

Principles of method if other than guideline:

Three test groups of animals were treated for 4 hour, 1 hour an 3 minutes respectively using occlusive conditions. An application site of 2x2 cm was covered with the liquid test substance. After the application time (4 h) the skin was washed with Lutrol or water/Lutrol mixture (1:1). The animals were observed for 8 days and skin changes were recorded. The report describes findings after 4, 24 and 48 hours and at the end of the observation period (8 days).

GLP compliance:

no

Species:

rabbit

Strain:

Vienna White

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: M.GAUKLER (6050 Offenbach)
- Weight at study initiation: 4hr test: 3.4 kg, 1hr test: 3.3 kg, 3 minut test: 2.9 kg
- Diet: Ssniff K, standard diet for rabbits and guinea pigs (Firma INTERMAST GMBH, Soest), ad libitum
- Water: ad libitum

Type of coverage:

occlusive

Preparation of test site:

shaved

Vehicle:

water

Controls:

no

Amount / concentration applied:

TEST MATERIAL
- Amount applied: 0.5 g
- Concentration: 80% aqueous preparation

Duration of treatment / exposure:

4 hours, 1 hour and, 3 minutes

Observation period:

8 days

Number of animals:

4 hour test: 3 male and 3 female
1 hour test: 1 male and 1 female
3 minute test: 1 male and 1 female

Details on study design:

Approximately 15-24 hours before treatment, the backs and sides of the animals were shaved with an electric clipper. On test day 1, a skin area of approx 2 x 2 cm was exposed for 4 hours, 1 hour and 3 minutes using a patch holding the chemical. During exposure the test areas were covered with inert foil and fixed with adhesive bandage. In the 3 minute exposure test the test patches were held manually against the animals. After exposure the treated skin was washed with Lutrol or a water/Lutrol mixture (1:1) and dried with cellulose towels.

TEST SITE
- Area of exposure: 2 x 2 cm
- Type of wrap: rubberised linnencloth, fixed with adhesive tape

REMOVAL OF TEST SUBSTANCE
- Washing: with Lutrol (50% or 100%) and dried with cellulose
- Time after start of exposure: up to 4 h

Irritation parameter:

edema score

Basis:

animal #1

Time point:

24/48 h

Score:

0.5

Max. score:

4

Reversibility:

not fully reversible within: 8 days

Irritation parameter:

edema score

Basis:

animal #2

Time point:

24/48 h

Score:

1.5

Max. score:

4

Reversibility:

not fully reversible within: 8 days

Irritation parameter:

edema score

Basis:

animal #3

Time point:

24/48 h

Score:

2

Max. score:

4

Reversibility:

not fully reversible within: 8 days

Irritation parameter:

edema score

Basis:

animal #4

Time point:

24/48 h

Score:

2

Max. score:

4

Reversibility:

not fully reversible within: 8 days

Remarks on result:

other: necrosis observed

Irritation parameter:

edema score

Basis:

animal #5

Time point:

24/48 h

Score:

1

Max. score:

4

Reversibility:

fully reversible within: 8 days

Irritation parameter:

edema score

Basis:

animal #6

Time point:

24/48 h

Score:

0

Max. score:

4

Irritation parameter:

erythema score

Basis:

animal #1

Time point:

24/48 h

Score:

1.5

Max. score:

4

Reversibility:

not fully reversible within: 8 days

Irritation parameter:

erythema score

Basis:

animal #2

Time point:

24/48 h

Score:

4

Max. score:

4

Reversibility:

not fully reversible within: 8 days

Remarks on result:

other: necrosis observed

Irritation parameter:

erythema score

Basis:

animal #3

Time point:

24/48 h

Score:

2.5

Max. score:

4

Reversibility:

not fully reversible within: 8 days

Remarks on result:

other: necrosis observed

Irritation parameter:

erythema score

Basis:

animal #4

Time point:

24/48 h

Score:

1.5

Max. score:

4

Reversibility:

not fully reversible within: 8 days

Remarks on result:

other: necrosis observed

Irritation parameter:

erythema score

Basis:

animal #5

Time point:

24/48 h

Score:

1

Max. score:

4

Reversibility:

fully reversible within: 8 days

Irritation parameter:

erythema score

Basis:

animal #6

Time point:

24/48 h

Score:

0.5

Max. score:

4

Reversibility:

fully reversible within: 8 days

Irritation parameter:

erythema score

Remarks:

1 h exposure

Basis:

animal #1

Time point:

24/48 h

Score:

3

Max. score:

4

Reversibility:

not fully reversible within: 8 days

Remarks on result:

other: patchy superficial necrosis and scale formation

Irritation parameter:

erythema score

Remarks:

1 h exposure

Basis:

animal #2

Time point:

24/48 h

Score:

1

Max. score:

4

Reversibility:

not fully reversible within: 8 days

Irritation parameter:

edema score

Remarks:

1 h exposure

Basis:

animal #1

Time point:

24/48 h

Score:

1.5

Max. score:

4

Reversibility:

not fully reversible within: 8 days

Irritation parameter:

edema score

Remarks:

1 h exposure

Basis:

animal #2

Time point:

24/48 h

Score:

0

Max. score:

4

Irritation parameter:

erythema score

Remarks:

3 min exposure

Basis:

mean

Remarks:

animal 1-2

Time point:

24/48 h

Score:

0

Max. score:

4

Remarks on result:

other: scale formation in one animal on day 8

Interpretation of results:

other: skin irritating

Endpoint conclusion

Endpoint conclusion:

adverse effect observed (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:

comparable to guideline study with acceptable restrictions

Remarks:

Meets generally accepted scientific standards, well documented and acceptable for assessment

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 405 (Acute Eye Irritation / Corrosion)

Version / remarks:

prior to the adoption of OECD405 in 1981

Principles of method if other than guideline:

Method: BASF-Test: 50 µL of the test substance were applied to the conjunctival sac of one eye in 2 animals. The animals were observed after 10 min, 1 and 3h on the day of treatment and up to 8 days afterwards. Findings were recorded daily. The eyes were not washed out after 24 hours as specified in OECD Guideline 405. The report describes findings after 1 and 24 hours and at the end of the observation period. For final evaluation, the findings after 48 and 72 hours from the raw data were taken into account.

GLP compliance:

no

Species:

rabbit

Strain:

Vienna White

Details on test animals or tissues and environmental conditions:

TEST ANIMALS
- Weight at study initiation: ca. 2.92 kg

Vehicle:

unchanged (no vehicle)

Controls:

other: talc powder in the left eye

Amount / concentration applied:

TEST MATERIAL
- Amount(s) applied (volume or weight with unit): 0.05 mL

Duration of treatment / exposure:

single application

Observation period (in vivo):

8 days

Number of animals or in vitro replicates:

2

Irritation parameter:

conjunctivae score

Basis:

animal #1

Time point:

24 h

Score:

2

Max. score:

3

Reversibility:

not fully reversible within: 8 days

Irritation parameter:

conjunctivae score

Basis:

animal #2

Time point:

24 h

Score:

2

Max. score:

3

Reversibility:

not fully reversible within: 8 days

Irritation parameter:

cornea opacity score

Basis:

animal #1

Time point:

24 h

Score:

3

Max. score:

4

Reversibility:

not fully reversible within: 8 days

Irritation parameter:

cornea opacity score

Basis:

animal #2

Time point:

24 h

Score:

3

Max. score:

4

Reversibility:

not fully reversible within: 8 days

Irritation parameter:

chemosis score

Basis:

animal #1

Time point:

24 h

Score:

1

Max. score:

4

Reversibility:

not fully reversible within: 8 days

Irritation parameter:

chemosis score

Basis:

animal #2

Time point:

24 h

Score:

2

Max. score:

4

Reversibility:

not fully reversible within: 8 days

Irritation parameter:

iris score

Basis:

mean

Remarks:

animal 1-2

Time point:

24 h

Score:

2

Max. score:

2

Reversibility:

not fully reversible within: 8 days

Remarks on result:

other: Mucosal bleeding

Irritant / corrosive response data:

After 8 days, scarring of the eyelids was observed. During the whole observation period, hemorrhage of mucous membranes was observed.

Interpretation of results:

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

Endpoint conclusion

Endpoint conclusion:

adverse effect observed (irritating)

Additional information

Skin irritation
In a skin irritation test similar to OECD guideline 404, the test substance was applied in 80% aqueous solution to the skin of Vienna White Rabbits (1965, RL2). Animals were treated for 1, 5, 15 min and 20 hours using occlusive conditions. Observation took place for 8 days and skin changes were recorded daily. Slight erythema and edema was observed after an exposure of 20 hours. No signs of erythema nor edema were observed after an exposure of 1, 5 or 15 minutes. 1,2-Dimethylimidazole was judged not irritating to the skin.

In another study similar to OECD guideline 404, Vienna White rabbits were exposed to an 80% aqueous solution of 1,2-dimethylimidazole under occlusive conditions for 3 minutes (1 animal/sex/dose), 1 hour (1 animal/sex/dose) or 4 hours (3 animals/sex/dose), followed by an 8-day observation period (1980, RL2). Animals exposed for 1 and 4 hours showed slight to strong erythema and edema and superficial but not full-thickness necrosis throughout the 8-day observation period. 1,2-Dimethylimidazole was judged severly irritating but not corrosive to the skin.

Eye irritation
In an eye irritation test comparable to OECD guideline 405, 50 µL of the test substance was applied to the conjunctival sac of the eyes of 2 Vienna White rabbits (1965, RL2). Animals were observed after 10 min, 1 and 3h on the day of treatment and at up to 8 days after the treatment. Application of the test substance led (after 8 days) to a conjunctivea score of 2 a cornea score of 2 and a chemosis score of 1. After 8 days, scarring of the eyelids was observed. Effects observed where not reversible within 8 days. During the whole observation period, hemorrhage of mucous membranes was observed. 1,2-Dimethylimidazole was judged irritating to the eyes with the risk of serious damage.

Justification for classification or non-classification

Based on the available data, 1,2 -dimethylimidazole has to be classified for skin irritation and eye damage. According to the EU Classification, Labelling and Packaging of Substances and Mixtures (CLP) Regulation (EC) No. 1272/2008, the classification is H315, Cat. 2 and H318, Cat. 1, which is in accordance with Annex VI.