Sodium salts of substituted amino acid (2)

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:

23 March 2009 - 06 April 2009

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

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

Test material information

Constituent 1

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)

Results

Results 1

Parameter:

SI

Value:

1.1

Test group / Remarks:

10, 25 and 50%

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.

Results 2

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 does not have to be classified and has no obligatory labeling requirement for sensitization by skin contact.