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Toxicological information

Skin sensitisation

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Administrative data

Endpoint:
skin sensitisation: in vivo (LLNA)
Type of information:
experimental study
Adequacy of study:
key study
Study period:
2009-04-21 to 2009-05-13
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: Guideline-conform study under GLP without deviations

Data source

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

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 429 (Skin Sensitisation: Local Lymph Node Assay)
GLP compliance:
yes (incl. certificate)
Remarks:
Copy of GLP certificate and GLP compliance statement attached to full study report.
Type of study:
mouse local lymph node assay (LLNA)

Test material

Reference
Name:
Unnamed
Type:
Constituent
Type:
Constituent

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

Study design: in vivo (LLNA)

Vehicle:
dimethylformamide
Concentration:
5, 10, and 25%
No. of animals per dose:
4
Details on study design:
In order to study a possible allergenic potential of 1-Chlor-2,5-dimethoxy-4-nitrobenzol trocken, three groups each of four female mice were treated with different concentrations of the test item by topical application at the dorsum of each ear lobe (left and right) on three consecutive days. A control group of four mice was treated with the vehicle only. Five days after the first topical application, the mice were intravenously injected into a tail vein with radio-labelled thymidine (3H-methyl thymidine). Approximately five hours after intravenous injection, the mice were sacrificed and the draining auricular lymph nodes excised and pooled per group. Single cell suspensions of lymph node cells were prepared from pooled lymph nodes, which were subsequently washed and incubated with trichloroacetic acid overnight. The proliferative capacity of pooled lymph node cells was determined by the incorporation of 3H-methyl thymidine measured in a beta-scintillation counter. After the lymph nodes have been excised, both ears of mice were punched at the apical area (Ø 8 mm corresponding to 0.5 cm2). For each animal the weight of both punches was determined.
Positive control substance(s):
hexyl cinnamic aldehyde (CAS No 101-86-0)

Results and discussion

In vivo (LLNA)

Resultsopen allclose all
Parameter:
SI
Remarks on result:
other: Test item concentration: 5 %: 0.89 10 %: 0.75 25 %: 0.73
Parameter:
other: disintegrations per minute (DPM)
Remarks on result:
other: per lymph node: Test item concentration: 0 %: 853.7 DPM 5 %: 758.7 DPM 10 %: 644.3 DPM 25 %: 619.9 DPM

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

117

---

---

---

---

---

BG II

32

---

---

---

---

0

1

6904

6830

8

853.7

 

5

2

6144

6070

8

758.7

0.89

10

3

5229

5155

8

644.3

0.75

25

4

5034

4960

8

619.9

0.73

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, recordedprior to the first application and prior to treatment with3HTdR, was within the range commonly recorded for animals of this strain and age.

The individual body weight values are included in Annex 1.

EarWeights

Group

 

Test Item Concentration % (w/v)

Ear Weight (punches, mg/animal)

Mean

SD

1

0

27.06

1.85

2

5

28.98

1.79

3

10

28.58

0.79

4

25

27.84

0.48

The measured ear weights of all animals treated were recorded at necropsy. A relevant increase in ear weights was not observed.

Applicant's summary and conclusion

Interpretation of results:
not sensitising
Remarks:
Migrated information
Conclusions:
The test item 1-Chlor-2,5-dimethoxy-4-nitrobenzol trocken was not a skin sensitiser under the described conditions.
Executive summary:

In the study the test item 1-Chlor-2,5-dimethoxy-4-nitrobenzol trocken dissolved indimethylformamide 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%.

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 0.89, 0.75 and 0.73 were determined with the test item at concentrations of 5, 10 and 25% in dimethylformamide, respectively. The EC3 value could not be calculated, since none of the tested concentrations inducedan S.I. greater than 3.

The test item 1-Chlor-2,5-dimethoxy-4-nitrobenzol trocken was not a skin sensitiser in this assay.