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Administrative data

Endpoint:
skin sensitisation: in vivo (LLNA)
Type of information:
experimental study
Adequacy of study:
key study
Study period:
2009
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: well performed OECD study with GLP

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2009
Report date:
2009

Materials and methods

Test guideline
Qualifier:
according to guideline
Guideline:
OECD Guideline 429 (Skin Sensitisation: Local Lymph Node Assay)
GLP compliance:
yes
Type of study:
mouse local lymph node assay (LLNA)

Test material

Constituent 1
Chemical structure
Reference substance name:
3-nitro-p-toluic acid
EC Number:
202-549-3
EC Name:
3-nitro-p-toluic acid
Cas Number:
96-98-0
Molecular formula:
C8H7NO4
IUPAC Name:
4-methyl-3-nitrobenzoic acid
Details on test material:
Identity: Nitro-p-tolylsäure
CAS No: 96-98-0
Purity: 98,23 % (w/w)
Stability in solvent: > 72 h in DMSO and ethanol at room temperature
Storage: At room temperature
Expiration Date: January 19, 2011 (Statement of producer)

In vivo test system

Test animals

Species:
mouse
Strain:
CBA
Sex:
female
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: Harlan Laboratories B.V., Postbus 6174, NL - 5960 AD Horst / The Netherlands
- Age at study initiation: 8 - 12 weeks
- Weight at study initiation: 15 - 25 g
- Housing:group
- Diet (e.g. ad libitum): pelleted standard diet, ad libitum
- Water (e.g. ad libitum): tap water, ad libitum
- Acclimation period: At least 5 days prior to the start of dosing under test conditions after health examination. Only animals without any visible signs of illness will be used for the study

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22 + 2°C
- Humidity (%): 45-65%
- Photoperiod (hrs dark / hrs light): 12/12


IN-LIFE DATES: From: To:

Study design: in vivo (non-LLNA)

Details on study design:
RANGE FINDING TESTS:


MAIN STUDY
A. INDUCTION EXPOSURE
- No. of exposures:
- Exposure period:
- Test groups:
- Control group:
- Site:
- Frequency of applications:
- Duration:
- Concentrations:


B. CHALLENGE EXPOSURE
- No. of exposures:
- Day(s) of challenge:
- Exposure period:
- Test groups:
- Control group:
- Site:
- Concentrations:
- Evaluation (hr after challenge):


OTHER:

Study design: in vivo (LLNA)

Vehicle:
dimethylformamide
Concentration:
5, 10, 25%
No. of animals per dose:
4

Results and discussion

In vivo (LLNA)

Results
Parameter:
SI
Remarks on result:
other: 1.42, 2.20, and 1.57

Any other information on results incl. tables

Test item concentration % (w/v)

Group

Measurement DPM

Calculation

Result

DPM-BGa)

number of lymph nodes

DPM per lymph nodeb)

S.I.

---

BG I

25

---

---

---

---

---

BG II

39

---

---

---

---

0

1

2735

2703

8

337.9

 

5

2

3871

3839

8

479.9

1.42

10

3

5981

5949

8

743.6

2.20

25

4

4267

4235

8

529.4

1.57

BG=Background (1 ml 5% trichloroacetic acid) in duplicate 1=Control Group 2-4=Test Group S.I.=Stimulation Index

a) =The mean value was taken from the figures BG I and BG II b)=Since the lymph nodes of the animals of a dose group were pooled, DPM/node was determined by dividing the measured value by the number of lymph nodes pooled

The EC3 value could not be calculated, since all S.I.´s are below 3.

Viability / Mortality: No deaths occurred during the study period.

Clinical Signs: No symptoms of local toxicity at the ears of the animals and no systemic findings were observed during the study period.

Body Weights: The body weight of the animals, recorded prior to the first application and prior to treatment with3HTdR, was within the range commonly recorded for animals of this strain and age.

Ear Weights: The measured ear weights of all animals treated were recorded at necropsy. A weak increase in ear weights was observedand a statistically signifigance of the ear weight was determined (p=0.009).

Group

 

Test Item Concentration % (w/v)

Ear Weight (punches, mg/animal)

Mean

SD

1

-

25.77

1.4

2

5

27.02

2.2

3

10

30.89

0.8

4

25

29.02

2.3

Applicant's summary and conclusion

Interpretation of results:
not sensitising
Remarks:
Migrated information Criteria used for interpretation of results: EU
Conclusions:
The test item Nitro-p-tolylsäure was not a skin sensitiser under the described conditions.
Executive summary:

In the study the test item Nitro-p-tolylsäure dissolved in Dimethylformamide (DMF) was assessed for its possible contact allergenic potential.

For this purpose a local lymph node assay was performed using test item concentrations of 5, 10 and 25%. A weak increase in the ear punch biopsies was observed in the groups treated with 10 and 25% and a statistically signifigance of the ear weight was determined

(p=0.009).

The animals 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 1.42, 2.20 and 1.57 were determined with the test item at concentrations of 5, 10 and 25% in DMF, respectively.

The test item Nitro-p-tolylsäure was not a skin sensitiser in this assay.