Reaction mass of 3-(2-{3-cyanato-5-[2-(3-cyanatoaryl)heteropolycycle-5-yl]aryl}heteropolycycle-5-yl)aryl cyanate and heteropolycycle -2,5-diyldi-3,1-arylene dicyanate

Endpoint summary

Description of key information

Sensitisation was tested on mice in a LLNA test according to OECD no. 429. The test item revealed sensitizing properties and needs to be regarded as a potential skin sensitizer.

Key value for chemical safety assessment

Skin sensitisation

Link to relevant study records

Reference

Reference 1

Endpoint:

skin sensitisation: in vivo (LLNA)

Type of information:

experimental study

Adequacy of study:

key study

Study period:

25 November 2012 - 28 March 2012

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

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

Qualifier:

according to guideline

Guideline:

EU Method B.42 (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: a reputable supplier
- Age at study initiation: 8-12 weeks
- Weight at study initiation: 15.5 to 21.6 g
- Acclimation period: 7 days
- Housing: animals were housed two animals per cage, in solid bottomed polycarbonate cages with a stainless steel mesh lid. Each cage contained a quantity of autoclaved wood flake bedding, additionally Nestlets and a plastic shelter were included for environmental enrichment.
- Diet (e.g. ad libitum): The animals were allowed free access to a standard rodent diet (Rat and Mouse No. 1 Maintenance Diet). This diet contained no added antibiotic or other chemotherapeutic or prophylactic agent.
- Water (e.g. ad libitum): Potable water taken from the public supply was freely available via polycarbonate bottles fitted with sipper tubes.

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 19 to 23°C
- Humidity (%): 40 to 70%
- Air changes (per hr): not reported
- Photoperiod (hrs dark / hrs light): Artificial lighting was controlled to give a cycle of 12 hours continuous light and 12 hours continuous dark per 24 hours.

IN-LIFE DATES
- From: 1st December 2011
- To: 3rd January 2012

Vehicle:

acetone/olive oil (4:1 v/v)

Concentration:

preliminary test: 10, 25% and 50% w/v
main test: 5, 10 and 25% w/v

No. of animals per dose:

2 in preliminary test and 4 in main test

Details on study design:

RANGE FINDING TESTS:
- Compound solubility: A vehicle trial performed with LZ1554 showed that it formed a brown solution at 50% w/v in acetone:olive oil (4:1 v/v), which was satisfactory for dose administration.
- Irritation: 50% w/v was the highest achieved concentration, but due to an increase in ear thickness recorded at this level, the next highest concentrations of 10 and 25% w/v were used in the main test.
- Lymph node proliferation response: not applicable

MAIN STUDY

ANIMAL ASSIGNMENT AND TREATMENT
- Name of test method: The animals were allocated without conscious bias to cages within the treatment groups.
- Criteria used to consider a positive response: Results for each treatment group were expressed as the Stimulation Index (SI), derived by dividing the mean dpm/mouse for each treated group and the positive control group by the mean dpm/mouse in the vehicle control group. If the SI is 3 or more, the test substance is regarded as a skin sensitizer.

TREATMENT PREPARATION AND ADMINISTRATION:
The test substance, LZ1554, was prepared for administration as a series of graded concentrations in the vehicle, by direct dilution.
The test substance was used as supplied and all formulations were prepared on the day of dosing at the required concentration(s).
The absorption of the test substance was not determined.

In the main phase of the study, five days following the first topical application of test substance (Day 6) all mice were injected via the tail vein with 250 µL of phosphate buffered saline containing 3H-methyl Thymidinea (3HTdR: 80 µCi/mL) giving a nominal 20 µ0Ci to each mouse. The injection into the tail vein was carried out using a plastic syringe and needle after the mouse had been heated in a warming chamber.

Positive control substance(s):

hexyl cinnamic aldehyde (CAS No 101-86-0)

Statistics:

Not applicable

Positive control results:

The SI for the positive control substance hexyl cinnamic aldehyde (HCA), was 10.2 which demonstrates the validity of this study.

Key result

Parameter:

SI

Value:

11.5

Test group / Remarks:

Concentration 5%

Key result

Parameter:

SI

Value:

19.5

Test group / Remarks:

Concentration 10%

Key result

Parameter:

SI

Value:

31.9

Test group / Remarks:

Concentration 25%

Key result

Parameter:

EC3

Value:

2.4

Remarks on result:

other: expressed in %

PRELIMINMARY TEST

There were no deaths and no signs of ill health were observed during this study.

No erythema was observed on the ears of any mouse on Days 1 to 6.

There was evidence of an effect of treatment on ear thickness for animals that received 50% w/v. Ear thickness on Day 6 was approximately 113 to 129% pre-dose values. There was no indication of an effect on ear thickness at 10 or 25% w/v.

There was no indication of an overt effect of treatment on bodyweight gain. On the basis of the results from the preliminary investigation, 25% w/v was considered a suitable high concentration for administration in the main phase of the study.

MAIN TEST

There were no deaths and no signs of ill health or toxicity were observed during this study.

No signs of dermal irritation were seen on the ears during the study. There was no indication of an effect of treatment on bodyweight gain.

Interpretation of results:

sensitising

Remarks:

Migrated information Criteria used for interpretation of results: EU

Conclusions:

LZ1554 is regarded as a potential skin sensitizer.
LZ1554 is classified as a skin sensitizer (category 1, sub category 1B) according to the Commission Regulation (EU) No. 286/2001 amending Regulation (EC) No. 1272/2008 on classification, labelling and packaging of substances and mixtures.

Executive summary:

The skin sensitization potential was determined in a GLP-compliant study in accordance with OECD no. 429 (Local Lymph Node Assay).

Reference 2

Endpoint:

skin sensitisation: in vitro

Data waiving:

study scientifically not necessary / other information available

Justification for data waiving:

an in vitro skin sensitisation study does not need to be conducted because adequate data from an in vivo skin sensitisation study are available

Endpoint conclusion

Endpoint conclusion:

adverse effect observed (sensitising)

Additional information:

Sensitisation was tested on mice in a LLNA test according to OECD no. 429. The test item revealed sensitizing properties and needs to be regarded as a potential skin sensitizer.

Respiratory sensitisation

Endpoint conclusion

Endpoint conclusion:

no study available

Justification for classification or non-classification

Based on the data available the substance is classified and labeled as "Skin sensitizer Category 1, Subcategory 1B; H317: May cause an allergic skin reaction" according to Regulation 1272/2008/EC (CLP).