Urea, reaction products with formaldehyde and glyoxal

Endpoint summary

Key value for chemical safety assessment

Skin sensitisation

Link to relevant study records

Reference

Endpoint:

skin sensitisation: in vivo (LLNA)

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 429 (Skin Sensitisation: Local Lymph Node Assay)

GLP compliance:

yes (incl. QA statement)

Type of study:

mouse local lymph node assay (LLNA)

Species:

mouse

Strain:

CBA

Sex:

female

Details on test animals and environmental conditions:

TEST ANIMALS
- Source: Charles River, Research Model and Services, Sulzfeld, Germany
- Age at study initiation: 8 - 12 weeks
- Weight at study initiation: 17.0 g - 20.0 g
- Housing:single housed
- Diet (e.g. ad libitum): ad libitum
- Water (e.g. ad libitum): ad libitum

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 20 - 24
- Humidity (%): 30 - 70
- Photoperiod (hrs dark / hrs light): 12/12

Vehicle:

other: 1% Pluroic L 92 Surfactant in highly de-ionized water

Concentration:

60 % w/w in 1% aqueous Pluronic

No. of animals per dose:

5

Details on study design:

Groups of 5 female CBA/J mice each were treated with a 60% w/w preparation of the test substance in 1% aqueous Pluronic® or with the vehicle alone. The 60% preparation was the maximum technically applicable concentration due to the sticky properties of the test substance.

The study was carried out as a limit test, using 1 test group and 1 control group. Each test animal was applied with 25 µL per ear of the testsubstance preparation to the dorsum of both ears for three consecutive days. The control group was treated with 25 µL per ear of the vehicle alone.

Three days after the last application the mice were injected intravenously with 20 µL of ³H-thymidine in 250 µL of sterile saline into a tail vein. About 5 hours after the ³H-thymidine injection, the mice were sacrificed and the auricular lymph nodes were removed. The weights of each animal’s pooled lymph nodes were determined. Thereafter lymph nodes were pooled group wise and further evaluated by measuring their cellular content and ³H-thymidine incorporation into the lymph node cells (indicators of cell proliferation). Moreover, a defined area with a diameter of 0.8 cm was punched out of the apical part of each ear and for each group the weight of the pooled punches was determined in order to obtain an indication of possible skin irritation.

On study day five (about 66 to 72 hours after the last application of test substance to the ears) the mice were injected intravenously with 20 µCi of 3H-thymidine in 250 µl of sterile saline into a tail vein.

The animals were sacrificed on study day 5 about 5 hours after 3H-thymidine injection by cervical dislocation.

Immediately after the death of each animal a circular piece of tissue (diameter 0.8 cm) was punched out of the apical part of each ear of all animals. The weight of the pooled punches was determined for each test group. These measurements serve for detecting a potential inflammatory ear swelling.

Immediately after removal of the ear punches the left and right auricular lymph nodes were dissected. The weight of the pooled lymph nodes from both sides was determined for each animal.

A concurrent positive control (reliability check) with a known sensitizer was not included into this study. Studies using the positive control substance Alpha-Hexylcinnamaldehyde, techn. 85% are performed twice a year in the laboratory in order to show that the test system is able to detect sensitizing compounds under the test conditions chosen.

Parameter:

SI

Remarks on result:

other: 2.31

Parameter:

other: disintegrations per minute (DPM)

Remarks on result:

other: at 60% w/w test substance 2222.9 dpm

Test group	Treatment	Cell Count Stimulation Index	³H-thymidine incorporation Stimulatin Index	Lymph Node Weight Stimulation Index	Ear Weight Stimulation Index
1	Vehicle 1% aqueous Pluronic	1.00	1.00	1.00	1.00
2	60% in 1% aqueous Pluronic	1.24	2.31	1.08	1.21

No signs of systemic toxicity were noticed. 

 

When applied as 60% preparation in 1% aqueous Pluronic®, the test substance did not induce a biologically relevant response (no increase to 1.5 fold or above of control value = stimulation index (SI) ≥ 1.5) in the auricular lymph node cell counts.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not sensitising)

Additional information:

Skin sensitisation:

In a Murine Local Lymph Node Assay according to OECD TG 429 in compliance with GLP, the test substance did not show a skin sensitising effect (BASF SE, 2010).

There are several reports available concerning skin sensitisation in humans (Malten, 1964; Andersen & Harman, 1982; Tegner, 1985; Fregert & Tegner, 1971; Scheman et al., 1998). However, these reports do not allow to specify this test substance as the cause of contact eczema. Furthermore, on the basis of these reports the incidence of contact dermatitis from textiles finished with the test substance is regarded to be very low, especially compared to the wide spread use (evaluated in OECD SIDS, 2002).

Migrated from Short description of key information:
Skin sensitisation (LLNA): not sensitising

Respiratory sensitisation

Endpoint conclusion

Endpoint conclusion:

no study available

Additional information:

Migrated from Short description of key information:
There are no data available concerning respiratory sensitisation of the test substance.

Justification for classification or non-classification

GHS classification according to Annex I 1272/2008 CLP (EU GHS):

no classification warranted.

If the formaldehyde content is at or above 0.2 % classification and labelling with Skin Sens. 1, H317 is warranted due to the specific concentration limit of formaldehyde concerning skin sensitisation (Skin Sens. 1; H317: C ≥ 0.2%).