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Acute Toxicity: dermal

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acute toxicity: dermal
Type of information:
migrated information: read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
key study
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Klimisch reliability of study is 1 (GLP guideline study); according to ECHA Practical Guide 6 rel. 2 is selected from the IUCLID pick-list as this should be the maximum score for read-across.

Data source

Reference Type:
study report
Report date:

Materials and methods

Test guideline
according to guideline
OECD Guideline 402 (Acute Dermal Toxicity)
Version / remarks:
GLP compliance:
yes (incl. QA statement)
Test type:
standard acute method
Limit test:

Test material

Constituent 1
Reference substance name:
HDI oligomers, isocyanurate
HDI oligomers, isocyanurate

Test animals

Details on test animals or test system and environmental conditions:
- Strain: Sprague-Dawley CD (Crl: CD (SD) IGS BR)
- Source: Charles River Ltd, Margate, Kent, UK.
- Age at study initiation: 8 to 12 weeks
- Weight at study initiation: At least 200 g; the weight variation did not exceed +/- 20% of the mean weight for each sex.
- Housing: individually during the 24-hour exposure period and in groups of 5 for the remainder of the study; the animals were housed in suspended solid-floor polypropylene cages furnished with woodflakes.
- Diet and water: ad libitum
- Acclimation period: at least 5 days

- Temperature (°C): 19-25
- Humidity (%):30-70
- Air changes (per hr): at least 15
- Photoperiod (hrs dark / hrs light): 12/12

Administration / exposure

Type of coverage:
unchanged (no vehicle)
Details on dermal exposure:
- Area of exposure: On the day before treatment the back and flanks of each animal were clipped free of hair. The calculated weight of test material, as received, was applied as evenly as possible to an area of shorn skin (approximately 10% of the total body surface area) using a graduated syringe. A piece of surgical gauze was placed over the treatment area and semi-occluded with a piece of self-adhesive bandage.

- After the 24-hour contact period the bandage was carefully removed and the treated skin and surrounding hair wiped with cotton wool moistened with distilled water to remove any residual test material.
Duration of exposure:
24 hours
2000 mg/kg bw
No. of animals per sex per dose:
Control animals:
Details on study design:
- Duration of observation period following administration: 14 days
- Frequency of observations: The animals were observed for deaths or overt signs of toxicity 30 min., 1, 2 and 4 hours after dosing and once daily thereafter. After removal of the dressings and subsequently once daily for 14 days, the test sites were examined for evidence of primary irritation and scored according to Draize (Dermal and Eye Toxicity Tests, in: Principles and Procedures for Evaluating the Toxicity of Household Substances, National Academy of Sciences, Washington DC, 1977, p. 31).
- Frequency of weighing: Individual bodyweights were recorded prior to application of the test material on day 0 and on days 7 and 14.
- Necropsy of survivors performed: yes
Using the mortality data obtained, an estimate of the acute dermal median lethal dose of the test material was made.

Results and discussion

Effect levels
Dose descriptor:
Effect level:
> 2 000 mg/kg bw
There were no deaths.
Clinical signs:
There were no signs of systemic toxicity.
Body weight:
All animals showed expected gains in bodyweight over the study period.
Gross pathology:
No abnormalities were noted at necropsy.
Other findings:
There were no signs of dermal irritation.

Any other information on results incl. tables

For (2,4,6-trioxotriazine-1,3,5(2H,4H,6H)-triyl)tris(hexamethylene) isocyanate (EC 223-242-0, CAS 3779-63-3, mono constituent substance), in the following referred to as "HDI Trimer pure", a read across from the close structural analogue HDI oligomers, isocyanurate type (EC 931-274-8, CAS 28182-81-2, UVCB) is applied. A justification for the read-across with special focus on inhalation toxicity was elaborated and is attached to the chapter endpoint summary. Based on this justification all available toxicological data for HDI oligomers, isocyanurate type can be used for the toxicological evaluation of HDI Trimer pure. This approach is in accordance with Annex XI, section 1.5 of the REACH Regulation (EC) No 1907/2006.

Applicant's summary and conclusion

Executive summary:

An acute dermal toxicity study was conducted according to OECD TG 402. For this purpose the limit dose of 2000 mg/kg bw of the test substance was applied semi-occlusive on 5 male and 5 female rats for 24 hours.

No mortalities, no signs of systemic toxicity and no effects on body weight gains were observed during the 14 -day observation period. Additionally no signs of dermal irritation were noted. Necropsy was unobtrusive. Thus, the LD50 was concluded to be > 2000 mg/kg bw.