2-[(4-chloro-2-nitrophenyl)azo]-N-(2-methoxyphenyl)-3-oxobutyramide

Endpoint summary

Description of key information

The test item was assessed for its possible contact allergenic potential in a local lymph node assay according to OECD TG 429. The test was performed using test item concentrations of 2.5, 5 and 10% (w/v). The animals (5 female mice/dose group) did not show any clinical signs during the course of the study and no cases of mortality were observed. In this study Stimulation Indices (S.I.) of 0.88, 0.95 and 1 .50 were determined with the test item at concentrations of 2.5, 5 and 10% (w/v) in DMSO, respectively. The results obtained with the positive control confirmed the validity of the test. The test item was not a skin sensitiser under the conditions tested.

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:

From 01 FEB 2005 to 15 FEB 2005

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: guideline study (OECD TG 429) GLP compliant

Qualifier:

according to guideline

Guideline:

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

Deviations:

no

GLP compliance:

yes

Type of study:

mouse local lymph node assay (LLNA)

Species:

mouse

Strain:

CBA

Sex:

female

Details on test animals and environmental conditions:

TEST ANIMALS
- strain: CBA/CaOlaHsd
- Source: Harlan Netherlands, Horst/The Netherlands
- Age at study initiation: 8-12 weeks (beginning of acclimatization)
- Weight at study initiation: mean: 17.8 +/- 1.1 g
- Housing: individually, Makrolon Type I cages
- Diet: pelleted standard diet (Harlan Winkelmann, Borchen/Germany), ad libitum
- Water: tap water, ad libitum
- Acclimatization: yes (acclimatization period not given)


ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22 +/-3
- Humidity (%): 20-70
- Photoperiod (hrs dark / hrs light): 12 hrs/12 hrs

Vehicle:

dimethyl sulphoxide

Concentration:

0%, 2.5%, 5%, 10% (w/v)

No. of animals per dose:

5 females per dose group
2 females in the pre-test

Details on study design:

RANGE FINDING TESTS:
- non GLP
- Compound solubility: 10% (w/v) suspension in DMSO was the highest technically applicable concentration; higher concentrations could also not be achieved with other vehicles
- Irritation: no irritation effects were observed at concentrations of 1.25, 2.5, 5.0 and 10% (w/v) after a single application
- Systemic toxicity: not observed up to the highest concentration tested
- Lymph node proliferation response: no data


MAIN STUDY
ANIMAL ASSIGNMENT AND TREATMENT
- Name of test method: LLNA
- Criteria used to consider a positive response:
1: exposure to at least one concentration of the test item resulted in an incorporation of 3H-methyl thymidine at least 3-fold or greater than that recorded in control mice as indicated by the stimulation index
2: data are compatible with a conventional dose response, although allowance must be made for either local toxicity or immunological suppression


TREATMENT PREPARATION AND ADMINISTRATION:
- individual preparation of weight volume dilutions using a magnetic stirrer as homogenizer
- test item preparations were made freshly before each dosing occasion
- 25 µl were spread over the entire dorsal surface of each ear lobe once daily for three consecutive days

Positive control substance(s):

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

Statistics:

- calculation of mean values and standard deviations for body weight
- Dunnett-test (ANOVA) to test for statistical significance of the results between the test item groups

Positive control results:

Stimulation indices of 0.92, 4.37 and 12.39 were determined with the positive control substance at concentrations of 5%, 10% and 25% (w/v), respectively, in acetone:olive oil (4+1). An EC3 value of 8.0% (w/v) was calculated.

Key result

Parameter:

SI

Value:

0.88

Test group / Remarks:

2.5%

Key result

Parameter:

SI

Value:

0.95

Test group / Remarks:

5%

Key result

Parameter:

SI

Value:

1.5

Test group / Remarks:

10%

Parameter:

SI

Remarks on result:

other: Stimulation indices were all below 3. The following SI were calculated: 2.5% test item: 0.88 5% test item: 0.95 10% test item: 1.50

Parameter:

other: disintegrations per minute (DPM)

Remarks on result:

other: Background: 5.7 or 0.2 dpm Control group: 1623 dpm/lymph node 2.5% test item: 1423 dpm/lymph node 5% test item: 1545 dpm/lymph node 10% test item: 2431 dpm/lymph node

The animals did not show any clinical signs during the course of the study and no cases of mortality were observed. The body weight of the animals was within the normal range. Calculation of the EC3 value was not performed, because no test concentration produced a SI of 3 or higher.

Interpretation of results:

not sensitising

Remarks:

Criteria used for interpretation of results: EU

Conclusions:

The test substance was not sensitising in this LLNA in concentrations up to 10% (w/v) in DMSO, the highest technically achievable concentration.

Executive summary:

The test item was assessed for its possible contact allergenic potential in a local lymph node assay according to OECD TG 429. The test was performed using test item concentrations of 2.5, 5 and 10% (w/v). The animals (5 female mice/dose group) did not show any clinical signs during the course of the study and no cases of mortality were observed. In this study Stimulation Indices (S.I.) of 0.88, 0.95 and 1 .50 were determined with the test item at concentrations of 2.5, 5 and 10% (w/v) in DMSO, respectively. The results obtained with the positive control confirmed the validity of the test. The test item was not a skin sensitiser under the conditions tested.

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:

no adverse effect observed (not sensitising)

Respiratory sensitisation

Endpoint conclusion

Endpoint conclusion:

no study available

Justification for classification or non-classification

No classification

The test item did no show skin sensitising properties in a LLNA study.