Tetrahydro-1,3,4,6-tetrakis(hydroxymethyl)imidazo[4,5-d]imidazole-2,5(1H,3H)-dione

Endpoint summary

Description of key information

Skin irritation/ corrosion: not irritant

Eye irritation: not irritant

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

Study period:

1978

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 404 (Acute Dermal Irritation / Corrosion)

Principles of method if other than guideline:

24h occlusive exposure to intact and abraded rabbit skin, with 7-day observation period

GLP compliance:

no

Remarks:

pre-GLP study

Specific details on test material used for the study:

SOURCE OF TEST MATERIAL
- Test substance no.: 78/15-1
- physical state: liquid

Species:

rabbit

Strain:

other: Albino

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Weight at study initiation: about 3 - 4 kg
- Housing: single
- Diet: ad libitum
- Water: ad libitum
- Acclimation period: > 7 d

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22 ± 2°C
- Humidity (%): 55 ± 10%
- Photoperiod (hrs dark / hrs light): 12/12

Type of coverage:

occlusive

Preparation of test site:

clipped

Vehicle:

unchanged (no vehicle)

Controls:

yes

Amount / concentration applied:

TEST MATERIAL
- Amount(s) applied: 0.5 ml
- Concentration (if solution): undiluted

Duration of treatment / exposure:

24 h

Observation period:

After 24 h and 72 h, and additional reading after 7 d in the case of findings after 72 h

Number of animals:

6

Details on study design:

TEST SITE
- Area of exposure: About 2.5 cm x 2.5 cm = about 6.25 cm²
- Type of wrap used: Covering of the material applied to the skin sites with gauze (2 layers 2.5 cm x 2.5 cm). Fixing of the gauze with an elastic bandage. Additionally, the trunk was wrapped in a PVC sheet.

REMOVAL OF TEST SUBSTANCE
- no

OBSERVATION TIME POINTS
- After 24 h and 72 h, and additional reading after 7 d in the case of findings after 72 h

SCORING SYSTEM: Scale for scoring the irritation index based on DRAIZE:
1 . Erythema and eschar formation:
No erythema 0
Very slight erythema (barely perceptible) 1
WeII-defined erythema 2
Moderate to severe erythema 3
Severe erythema (beet redness) to slight eschar formation (injuries in depth) 4

Total possible erythema score 4

2. Edema formation:
No edema 0
Very slight edema (barely perceptible) 1
Slight edema (edges of area weil defined by definite raising) 2
Moderate edema (raised approximately 1 mm) 3
Severe edema (raised more than 1 mm and extending beyond the area of exposure) 4

Total possible edema score 4

IRRITATION INDEX: ∑[(1)+(2)] / N

ASSESSMENT OF THE IRRITATION INDEX
0 to 0.5 non irritating
0.6 to 3.0 slightly irritating
3.1 to 5.0 moderately irritating
5.1 to 8.0 severely irritating

OTHER EXAMINATIONS
- Sacrifice of the rabbits: 7 d after application, assessment of the subcutaneous connective tissue and the muscles underneath at the application site

Irritation parameter:

erythema score

Basis:

mean

Time point:

other: 24h/72h

Score:

1.5

Max. score:

4

Reversibility:

fully reversible

Remarks on result:

other: scabs observed in 3 animals

Irritation parameter:

edema score

Basis:

mean

Time point:

other: 24h/72h

Score:

0.17

Max. score:

4

Reversibility:

fully reversible

Remarks on result:

no indication of irritation

Irritant / corrosive response data:

see section "Any other information on results incl. tables"

Other effects:

- Other adverse local effects: 24 h after application, the intact skin was blue colored in one rabbit. A slight induration of the abraded skin was detected in one other rabbit. The intact and abraded skin was sunken in places in one additional rabbit.
7 d after application, scabbing was observed on the abraded skin in all rabbits and also on the intact skin of 3 rabbits.

- Necropsy findings: Intact skin: In one rabbit, vessels in the subcutaneous connective tissue definitely injected; muscles without any abnormalities
Abraded skin: In two rabbits, vessels in the subcutaneous connective tissue definitely injected; muscles without any abnormalities

Individual results of skin irritation study on rabbits

Readings	Time after appl. (h)	Skin irritation index Rabbit No.						Total value (∑)	Mean (x)
		1	2	3	4	5	6
1. Erythema/ Eschar Formation
Intact skin	24	0	3	1	2	3	1	10	1.67
	72	0	2	1	2	3	0	8	1.33
Abraded skin	24	2	3	3	4	3	1	16	2.67
	72	1	2	3	3	3	1	13	2.17
2. Edema
Intact skin	24	0	2	0	0	0	0	2	0.33
	72	0	0	0	0	0	0	0	0
Abraded skin	24	0	0	0	1	2	1	4	0.67
	72	1	0	0	1	2	0	4	0.67

Interpretation of results:

GHS criteria not met

Conclusions:

The substance is not considered to be classified for irritation, because the GHS criteria are not met. The mean values of erythema as well as edema are below the value of 1.5, which is the range limit of category 3, for 3 out of the 6 animals. The remaining 3 animals showed erythema with mean values (24 h and 72 h) between 2 and 3.
3 of 6 animals showed formation of crusts 7 d after application. Although there was no later observation time point it can be assumed that these effects would have been reversible within an additional week.

Executive summary:

In this pre-GLP skin irritation study on rabbits the test substance was applied undiluted to the clipped skin (intact and abraded) of 6 rabbits. Untreated skin sites served as negative control. An occlusive coverage was used and the exposure period was 24 h. After 24 h and 72 h the effects were assessed and scaled based on Draize. An additional reading was made after 7 d in the case of findings after 72 h. The mean values of erythema as well as edema are below the value of 1.5, which is the range limit of category 3, for 3 out of the 6 animals. The remaining 3 animals showed erythema with mean values (24 h and 72 h) between 2 and 3. Thus the GHS criteria are not met and therefore the test substance is not considered to be classified for irritation.

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

Study period:

1978

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 405 (Acute Eye Irritation / Corrosion)

GLP compliance:

no

Specific details on test material used for the study:

SOURCE OF TEST MATERIAL
- Test substance number: 78/15-1

Species:

rabbit

Strain:

other: albino

Details on test animals or tissues and environmental conditions:

TEST ANIMALS
- Weight: about 3 to 4 kg
- Housing: individually housed in stainless steel cages without bedding
- Diet: standard pellet diet for rabbits, ad libitum
- Water: ad libitum
- Acclimation period: > 7 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22 +/- 1
- Humidity (%): 55 +/- 10
- Photoperiod (hrs dark / hrs light): 12/12, light from 07.00 - 19.00 hours

Vehicle:

unchanged (no vehicle)

Controls:

yes

Amount / concentration applied:

TEST MATERIAL
- Amounts applied: 0.1 ml

Duration of treatment / exposure:

single application in right or left eye

Observation period (in vivo):

1 h, 24 h, 48 h, and 72 h after instillation; in the case of irritation after 72 h up to 7 d

Number of animals or in vitro replicates:

6 animals in total

Details on study design:

REMOVAL OF TEST SUBSTANCE
- Rinsing after application: no

SCORING SYSTEM: see table 1, any other information

NEGATIVE CONTROL: untreated eye

Irritation parameter:

conjunctivae score

Basis:

mean

Time point:

24/48/72 h

Score:

0.7 - 6

Max. score:

3

Reversibility:

fully reversible within: 72 h

Irritation parameter:

chemosis score

Basis:

mean

Time point:

24/48/72 h

Score:

0.9

Max. score:

4

Reversibility:

fully reversible within: 72h

Irritation parameter:

cornea opacity score

Basis:

mean

Time point:

24/48/72 h

Score:

0

Max. score:

4

Remarks on result:

no indication of irritation

Irritation parameter:

iris score

Basis:

mean

Time point:

24/48/72 h

Score:

0

Max. score:

2

Remarks on result:

no indication of irritation

Irritant / corrosive response data:

1 h after application, all rabbits demonstrated slight to moderate redness and slight to severe swelling of the conjuntivae in the treated eyes.

Interpretation of results:

GHS criteria not met

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not irritating)

Respiratory irritation

Endpoint conclusion

Endpoint conclusion:

no study available

Additional information

Skin irritation/ corrosion:

In a pre-GLP skin irritation study the test substance was applied undiluted to the clipped skin (intact and abraded) of 6 albino rabbits (sex not specified). Untreated skin sites served as negative control. An occlusive coverage was used and the exposure period was 24 h. After 24 h and 72 h the effects were assessed and scaled based on Draize. An additional reading was made after 7 d in the case of findings after 72 h. The mean values of erythema as well as edema are below the value of 1.5, which is the range limit of category 3, for 3 out of the 6 animals. The remaining 3 animals showed erythema with mean values (24 h and 72 h) between 2 and 3. Three of six animals showed formation of crusts 7 d after application. Although there was no later observation time point it can be assumed that these effects would have been reversible within an additional week.

This result is supported by data from 6 volunteers, who did not show any skin reactions upon 24h exposure to the test substance, moistened either with oil or water.

Eye irritation:

6 albino rabbits were treated with 0.1ml of the test substance, which was applied to one eye (the other eye served as negative control). The severity of the irritation was assessed according to Draize. All animals showed slightly to moderate redness and swelling of the conjunctiva within the first 24 hours after application of the test susbstance. After 48 hours, slight redness (6/6 animals) and slight swelling (5/6 animals) was still observed and vanished completely in all animals after 72 h. All mean (24, 48, 72h) values remained below 1. Cornea and iris were not affected. Thus the substance is considered not to cause eye irritation.

Justification for classification or non-classification

The available experimental test data are reliable and suitable for classification purposes under Regulation 1272/2008. As a result the substance is not considered to be classified for irritation under Regulation (EC) No. 1272/2008.