Registration Dossier

Diss Factsheets

Toxicological information

Skin sensitisation

Currently viewing:

Administrative data

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:
23 March 2009 - 06 April 2009
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: The study was performed according to OECD guidelines and 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 (incl. QA statement)
Type of study:
mouse local lymph node assay (LLNA)

Test material

Reference
Name:
Unnamed
Type:
Constituent
Type:
Constituent
Details on test material:
Identification EDTN
Molecular formula C10H12N6
Molecular weight 216
CAS Number 5766-67-6
Description White powder
Batch CFC 9070
Purity 99.8 ± 0.5%
Test substance storage At room temperature in the dark
Stability under storage conditions Stable
Expiry date 13 January 2012

In vivo test system

Test animals

Species:
mouse
Strain:
CBA
Sex:
female
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: Charles River France, L’Arbresle Cedex, France.
- Age at study initiation: approximately 11 weeks
- Weight at study initiation: 21-25 grams
- Housing: Individual housing in labeled Macrolon cages (MI type; height 12.5 cm) containing
sterilized sawdust as bedding material (Litalabo, S.P.P.S., Argenteuil, France). Paper (Envirodri,
Wm. Lillico & Son (Wonham Mill Ltd), Surrey, United Kingdom) was supplied as cageenrichment.
The paper was removed on Day 1 prior to dosing and was supplied again after
scoring of the ears on Day 3.
- Diet (e.g. ad libitum): ad libitum
- Water (e.g. ad libitum): ad libitum
- Acclimation period: at least 5 days
ENVIRONMENTAL CONDITIONS
- Temperature (°C): 19.8-23.8
- Humidity (%): 39-88%
- Air changes (per hr): approximately 15
- Photoperiod (hrs dark / hrs light): 12/12
IN-LIFE DATES: From: 23 March 2009 To: 06 April 2009

Study design: in vivo (LLNA)

Vehicle:
propylene glycol
Concentration:
10-25-50% w/w
No. of animals per dose:
5
Details on study design:
- Compound solubility: homogeneity was obtained to visually acceptable levels
- Irritation: Slight erythema (barely perceptible) of the right ear at 50%
MAIN STUDY
ANIMAL ASSIGNMENT AND TREATMENT
- Name of test method: Local lymph node assay
- Criteria used to consider a positive response: DPM values are presented for each animal and for each dose group. A Stimulation Index (SI) is calculated for each group. The SI is the ratio of the DPM/group compared to DPM/vehicle control group. If the results indicate a SI ≥ 3, the test substance may be regarded as a skin sensitizer, based on test guidelines and recommendations done by ICCVAM.
TREATMENT PREPARATION AND ADMINISTRATION:
Three groups of five experimental animals were treated with test substance concentrations of 10%, 25% or 50% on three consecutive days, by open application on the ears (25 μL/ear). Five vehicle control animals were similarly treated, but with vehicle alone (Propylene glycol). Three days after the last exposure, all animals were injected with 3H-methyl thymidine and after five hours the draining (auricular) lymph nodes were excised. After precipitating the DNA of the lymph node cells, radioactivity measurements were performed.
Positive control substance(s):
hexyl cinnamic aldehyde (CAS No 101-86-0)
Statistics:
none

Results and discussion

Positive control results:
The SI values calculated for the substance concentrations 5, 10 and 25% were 2.0, 2.2 and 4.2 respectively. An EC3 value of 16.0 % was calculated using linear interpolation. The calculated EC3 value was found to be in the acceptable range of 2 and 20%. The results of the 6 monthly HCA reliability checks of the recent years were 13.1, 15.6, 14.1, 13.8 and 13.9%.
Based on the results, it was concluded that the Local Lymph Node Assay as performed at NOTOX is an appropriate model for testing for contact hypersensitivity.

In vivo (LLNA)

Resultsopen allclose all
Parameter:
SI
Remarks on result:
other: The SI values calculated for the substance concentrations 10, 25 and 50% were 1.1, 1.1 and 1.1, respectively.
Parameter:
other: disintegrations per minute (DPM)
Remarks on result:
other: Mean DPM/animal values for the experimental groups treated with test substance concentrations 10, 25 and 50% were 231, 237 and 242, respectively. The mean DPM/animal value for the vehicle control group was 212.

Any other information on results incl. tables

One DPM value was rejected and not used for interpretation (extremely large lymph node and outside historical range for vehicle control).

Applicant's summary and conclusion

Interpretation of results:
not sensitising
Remarks:
Migrated information
Conclusions:
Since there was no indication that the test substance could elicit an SI >= 3 when tested up to 50%, the test substance was considered not to be a skin sensitizer. Therefore, the test substance EDTN does not have to be classified and has no obligatory labeling requirement for sensitization by skin contact.
Executive summary:

Assessment of Contact Hypersensitivity to EDTN in the Mouse (Local Lymph Node Assay).

The study was carried out based on the guidelines described in: OECD, Section 4, Health Effects, No.429 (2002), EC, No 440/2008; B42: "Skin Sensitization: Local Lymph Node Assay" EPA, OPPTS 870.2600 (2003) “Skin Sensitization”.

Test substance concentrations selected for the main study were based on the results of a preliminary study.

In the main study, three groups of five experimental animals were treated with test substance concentrations of 10, 25 or 50% w/w on three consecutive days, by open application on the ears. Five vehicle control animals were similarly treated, but with vehicle alone (Propylene glycol). Three days after the last exposure, all animals were injected with 3H-methyl thymidine and after five hours the draining (auricular) lymph nodes were excised. After precipitating the DNA of the lymph node cells, radioactivity measurements were performed.

The activity was expressed as the number of Disintegrations Per Minute (DPM) and a stimulation index (SI) was subsequently calculated for each group. No irritation of the ears was observed in any of the animals examined. All auricular lymph nodes of the animals of the experimental and control groups were considered normal in size, except for one extremely enlarged lymph node in one animal of the control group. No macroscopic abnormalities of the surrounding area were noted.

Mean DPM/animal values for the experimental groups treated with test substance concentrations 10, 25 and 50% were 231, 237 and 242, respectively. The mean DPM/animal value for the vehicle control group was 212.

The SI values calculated for the substance concentrations 10, 25 and 50% were 1.1, 1.1 and 1.1, respectively. Since there was no indication that the test substance elicits an SI ≥ 3 when tested up to 50% w/w, i.e. the maximum test concentration in case of a solid, EDTN was considered not to be a skin sensitizer.