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

Skin irritation / corrosion

Administrative data

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

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1978

Report date:

1978

Materials and methods

Test guideline

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

Test material

Test material information

Constituent 1

Reference substance name:

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

EC Number:

226-408-0

EC Name:

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

Cas Number:

5395-50-6

Molecular formula:

C8H14N4O6

IUPAC Name:

1,3,4,6-tetrakis(hydroxymethyl)-octahydro-[1,3]diazolo[4,5-d]imidazole-2,5-dione

Test material form:

liquid

Specific details on test material used for the study:

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

Test animals

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

Test system

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

Results and discussion

In vivo

Results

Results 1

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

Results 2

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

Any other information on results incl. tables

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

Applicant's summary and conclusion

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.