p-toluenesulphonyl isocyanate

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:

migrated information: read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Study period:

October 2012 to January 2013

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Study performed according to OECD 429 and under GLP-conditions.

Reason / purpose for cross-reference:

reference to same study

Reason / purpose for cross-reference:

reference to other study

Qualifier:

according to guideline

Guideline:

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

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method B.42 (Skin Sensitisation: Local Lymph Node Assay)

Deviations:

no

Principles of method if other than guideline:

Not relevant

GLP compliance:

yes (incl. QA statement)

Type of study:

mouse local lymph node assay (LLNA)

Species:

mouse

Strain:

other: CBA/Ca

Sex:

female

Details on test animals and environmental conditions:

TEST ANIMALS
- Source: Harlan Laboratories UK Ltd., Oxon, UK
- Age at study initiation: 8 - 12 weeks
- Weight at study initiation: 15 - 23 g
- Housing: Animals were individually housed in suspended solid-floor polypropylene cages furnished with softwood woodflakes
- Diet (e.g. ad libitum): Ad libitum (2014C Teklad Global Rodent diet supplied by Harlan Laboratories UK Ltd., Oxon, UK
- Water (e.g. ad libitum): Ad libitum
- Acclimation period: at least 5 days

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

IN-LIFE DATES: From: 15 November 2012 To: 04 December 2012

Vehicle:

dimethylformamide

Concentration:

10%, 25% and 50%

No. of animals per dose:

5

Details on study design:

RANGE FINDING TESTS:
- Compound solubility: Dimethyl formamide produced the highest concentration that was suitable for dosing.
- Irritation: one mouse was treated daily with undiluted test item to the dorsal surface of each ear for three consecutive days. Local irritation was scored daily.

MAIN STUDY
ANIMAL ASSIGNMENT AND TREATMENT
- Name of test method: Local Lymph Node Assay (LLNA) - individual animal approach
- Criteria used to consider a positive response: Stimulation Index (SI) ≥ 3

TREATMENT PREPARATION AND ADMINISTRATION:
- The mice were treated by daily application of 25µL of the appropriate concentration of the test item to the dorsal surface of each ear for three consecutive days.
- The test item was formulated within two hours of being applied to the test system. It is assumed that the formulation was stable for this duration.

Positive control substance(s):

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

Statistics:

Data was processed to give group mean values for disintegrations per minute and standard deviations where appropriate. Individual and group mean disintegrations per minute values were assessed for dose reponse relationships by analysis of homogeneity of variance followed by one way analysis of variance (ANOVA). In the event of a significant result from the ANOVA, pairwise comparisons were performed between control and treated groups. For homogenous datasets Dunnett's Multiple Comparison test was used and for non-homogenous datasets Dunnett's T3 Multiple Comparison Method was used.

Positive control results:

SI expressed as the mean radioactive incorporation for α-Hexylcinnamaldehyde was 4.38, which is a positive result (SI ≥ 3).

Parameter:

SI

Remarks on result:

other: - 10%: 0.93 - 25%: 0.86 - 50%: 1.00

Parameter:

other: disintegrations per minute (DPM)

Remarks on result:

other: Mean DPM/animal (Standard Deviation) - Vehicle (0%): 2186.32 (± 939.12) - 10%: 2029.45 (± 836.32) - 25% 1890.47 (± 962.98) - 50% 2191.61 (± 670.48)

- Clinical observations and mortality data: no mortality was observed. No signs of systemic toxicity were noted in the test or control animals during the test.

- Bodyweight: Bodyweight changes of the test animals between Day 1 and Day 6 were comparable to those observed in the corresponding control group animals over the same period.

Interpretation of results:

not sensitising

Remarks:

Migrated information Criteria used for interpretation of results: EU

Conclusions:

Under the conditions of this study, p-Toluenesulphonamide was considered to be not sensitising. A maximum Stimulation Index of 1.00 for the highest tested dose (50%) indicates that the substance does not need to be classified as a sensitiser according to the criteria outlined in Annex I of 1272/2008/EC and Annex VI of 67/548/EEC.

Executive summary:

This Local Lymph Node Assay (OECD 429) was performed to determine the sensitising potential of p-Toluenesulphonamide in CBA/Ca mice. Groups of 5 mice were treated with 10, 25 or 50% p-Toluenesulphonamide v/v in dimethyl formamide. α-Hexylcinnamaldehyde (85% pure), prepared as a 15% v/v dilution in dimethyl formamide, was used as positive control. Clinical observations and bodyweights were recorded and lymph node proliferation was determined using 3HTdR incorporation.

The number of radioactive disintegrations per minute (dpm) reflect the proliferation reponse of lymph node cells, and were 2186.32, 2029.45, 1890.47, and 2191.61 mean dpm/animal for the 0%, 10%, 25%, and 50% concentration groups, respectively. This corresponds with a lymph node proliferation Stimulation Index (SI) of 0.93, 0.86 and 1.00, respectively, for the p-Toluenesulphonamide-treated groups (10%, 25%, 50%). No mortality and no signs of systemic toxicity were observed. No effects on bodyweight (gain) were observed.

Under the conditions of this study, p-Toluenesulphonamide was considered to be not sensitising. A maximum Stimulation Index of 1.00 for the highest tested dose (50%) indicates that the substance does not need to be classified as a sensitiser according to the criteria outlined in Annex I of 1272/2008/EC and Annex VI of 67/548/EEC.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not sensitising)

Additional information:

The result of PTSA is read across to PTSI. This is considered justified because PTSI is extremely reactive with water and reacts instantaneously into the source substance PTSA. Due to this extreme reactivity it is considered unethical to perform this study with PTSI on animals.

A Local Lymph Node Assay (OECD 429) was performed with PTSA to determine its sensitising potential in CBA/Ca mice. Groups of 5 mice were treated with 10, 25 or 50% p-Toluenesulphonamide v/v in dimethyl formamide. α-Hexylcinnamaldehyde (85% pure), prepared as a 15% v/v dilution in dimethyl formamide, was used as positive control. Clinical observations and bodyweights were recorded and lymph node proliferation was determined using 3HTdR incorporation.

A lymph node proliferation Stimulation Index (SI) of 0.93, 0.86 and 1.00 was observed for 10%, 25%, and 50% PTSA, respectively. No mortality and no signs of systemic toxicity were observed. No effects on bodyweight (gain) were observed. Under the conditions of this study, PTSA was considered to be not sensitising, as the maximum Stimulation Index of 1.00 for the highest tested dose (50%) indicates that the substance does not need to be classified as a sensitiser according to the criteria outlined in Annex I of 1272/2008/EC and Annex VI of 67/548/EEC.

Migrated from Short description of key information:
Local Lymph Node Assay (OECD429, GLP) with PTSA (max 50%): not sensitising

Justification for selection of skin sensitisation endpoint:
Reliable GLP study according to OECD 429

Respiratory sensitisation

Endpoint conclusion

Endpoint conclusion:

no study available

Additional information:

According to Annex VI of CLP, PTSI is classified for respiratory sensitisation.

Migrated from Short description of key information:
According to Annex VI of CLP, PTSI is classified for respiratory sensitisation.

Justification for classification or non-classification

Based on read across to the results of the key study with PTSA, PTSI does not need to be classified for skin sensitisation when considering the criteria outlined in Annex I of 1272/2008/EC and Annex VI of 67/548/EEC. However, based on Annex VI of 1272/2008/EC (CLP), PTSI has to be classified for respiratory sensitisation.