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Skin sensitisation

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Administrative data

skin sensitisation: in vivo (LLNA)
Type of information:
experimental study
Adequacy of study:
weight of evidence
Study period:
15 June 2010 to 05 July 2010
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: This study has been performed according to OECD and/or EC guidelines and according to GLP principles.

Data source

Reference Type:
study report
Report date:

Materials and methods

Test guidelineopen allclose all
according to guideline
OECD Guideline 429 (Skin Sensitisation: Local Lymph Node Assay)
according to guideline
EU Method B.42 (Skin Sensitisation: Local Lymph Node Assay)
according to guideline
EPA OPPTS 870.2600 (Skin Sensitisation)
GLP compliance:
yes (incl. QA statement)
Type of study:
mouse local lymph node assay (LLNA)

Test material

Constituent 1
Reference substance name:
Saccharomyces cerevisiae, ext.
EC Number:
EC Name:
Saccharomyces cerevisiae, ext.
Cas Number:
Molecular formula:
Not applicable as the substance is an UVCB
Yeast extract, Saccharomyces cerevisiae
Details on test material:
- Shortened name of test material: Saccharomyces cerevisiae, Extract
- Substance type: Light beige powder
- Physical state: Solid.
- Analytical purity: Not indicated by the sponsor; treated as 100% pure
- Lot/batch No.: 071002230
- Expiration date of the lot/batch: 31 May 2013
- Stability under test conditions: Stable under storage conditions
- Storage condition of test material: At room temperature in the dark
- Hygroscopic Yes, store in well-sealed container
- pH: 7.0 at concentration of 8%
- Stability at higher temperatures:Breakdown temperature > 100°C
- Stability in vehicle:
Propylene glycol: Unknown
- Solubility in vehicle:
Propylene glycol: Not indicated

In vivo test system

Test animals

Details on test animals and environmental conditions:
- Source: Charles River France, L’Arbresle Cedex, France.
- Age at study initiation: Young adult animals (approx. 10 weeks old)
- Weight at study initiation: Body weight variation was within +/- 20% of the sex mean.
- 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 (Enviro-dri, Wm. Lillico & Son (Wonham Mill Ltd), Surrey, United Kingdom) was supplied as cage-enrichment.
The paper was removed on Day 1 prior to dosing and was supplied again after scoring of the ears on Day 3. During the acclimatization period the accommodation was as described above except that the animals were group housed in Macrolon cages (MIII type; height 18 cm).
- Diet (e.g. ad libitum): Free access to pelleted rodent diet (SM R/M-Z from SSNIFF® Spezialdiäten GmbH, Soest, Germany).
- Water (e.g. ad libitum): Free access to tap water.
- Acclimation period: The acclimatization period was at least 5 days before the start of treatment under laboratory conditions. Accommodation was as described above except that the animals were group housed in Macrolon cages (MIII type; height 18 cm).
- Health inspection: A health inspection was performed prior to treatment, to ensure that the animals are in a good state of health. Special attention was paid to the ears, which were intact and free from any abnormality.

- Temperature (°C): 20.8 - 22.9ºC
- Humidity (%): 42 - 81%
Deviations from the maximum level of relative humidity (70%) occurred. Laboratory historical data do not indicate an effect of the deviations
- Air changes (per hr): approximately 15 air changes per hour
- Photoperiod (hrs dark / hrs light): 12 hours artificial fluorescent light and 12 hours darkness per day.

IN-LIFE DATES: From: 15 June 2010 to 05 July 2010

Study design: in vivo (LLNA)

propylene glycol
No. of animals per dose:
Details on study design:
- Compound solubility: The vehicle was selected based on trial formulations performed at NOTOX and on test substance data
supplied by the sponsor.
- Irritation: A preliminary irritation study was conducted in order to select the highest test substance concentration to be used in the main study. In principle, this concentration should be well tolerated systemically by the animals and may give moderate irritation (maximally grade 2; see section 6.6) at the highest concentration.
Two test substance concentrations were tested; a 25% and 50% concentration. The highest concentration was the maximum concentration as required in the test guidelines (undiluted for liquids, 50% for solids).
The test system, procedures and techniques were identical to those used during Days 1 to 3 of the main study unless otherwise specified. Two young adult animals were selected (8-14 weeks old, Harlan, Horst, The Netherlands). Each animal was treated with one concentration on three consecutive days. Approximately 3-4 hours after the last exposure, the irritation of the ears was assessed. Bodyweights were determined on Day 3. The animals were sacrificed after the final observation and no necropsy was performed.
- Lymph node proliferation response: Not determined in the preliminary irritation study.

- Name of test method: Local Lymph Node Assay
- Criteria used to consider a positive response: Disintegrations Per Minute (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 the test guideline and
recommendations done by ICCVAM. The results were evaluated according to the Globally Harmonized System of Classification
and Labeling of Chemicals (GHS) of the United Nations (2007) and the Regulation (EC) No 1272/2008 of the European
Parliament and of the Council of 16 December 2008 on classification, labeling and packaging of substances and mixtures.
Consideration was given to the EC3 value (the estimated test substance concentration that will give a SI =3).

The test substance formulations (w/w) were prepared within 4 hours prior to each treatment. No adjustment was made for
specific gravity of the vehicle. Homogeneity was obtained to visually acceptable levels.
Three groups of five animals were treated with one test substance concentration per group. The highest test substance
concentration was selected from the preliminary irritation study. One group of five animals was treated with vehicle.

Induction - Days 1, 2 and 3:
The dorsal surface of both ears was epidermally treated (25 μL/ear) with the test substance concentration, at approximately the
same time per day. The concentrations were mixed thoroughly using a vortex mixer immediately prior to dosing. The control
animals were treated the same as the experimental animals, except that the vehicle was administered instead of the test

Excision of the nodes - Day 6:
Each animal was injected via the tail vein with 0.25 mL of sterile phosphate buffered saline (PBS) (Merck, Darmstadt, Germany)
containing 20 μCi of 3H-methyl thymidine (PerkinElmer Life and Analytical Sciences, Boston, MA, US). After approximately five
hours, all animals were killed by intraperitoneal injection with Euthasol® 20% (AST Farma BV, Oudewater, The Netherlands).
The draining (auricular) lymph node of each ear was excised. The relative size of the nodes (as compared to normal) was
estimated by visual examination and abnormalities of the nodes and surrounding area were recorded. The nodes were pooled
for each animal in approximately 3 mL PBS.

Tissue processing for radioactivity - Day 6:
A single cell suspension of lymph node cells (LNC) was prepared in PBS by gentle separation through stainless steel gauze
(diameter 125 μm). LNC were washed twice with an excess of PBS by centrifugation at 200g for 10 minutes at 4ºC. To
precipitate the DNA, the LNC were exposed to 5% trichloroacetic acid (TCA) (Merck, Darmstadt, Germany) stored in the
refrigerator until the next day.

Radioactivity measurements - Day 7
Precipitates were recovered by centrifugation, resuspended in 1 mL TCA and transferred to 10 mL of Ultima Gold cocktail
(PerkinElmer Life and Analytical Sciences, Boston, MA, US) as the scintillation fluid. Radioactive measurements were performed
using a Packard scintillation counter (2800TR). Counting time was to a statistical precision of ± 0.2% or a maximum of 5 minutes
whichever came first. The scintillation counter was programmed to automatically subtract background and convert Counts Per
Minute (CPM) to Disintegrations Per Minute (DPM).
Mortality/Viability: Twice daily.
Toxicity: At least once daily.
Body weights: On Days 1 (pre-treatment) and 6.
Necropsy: No necropsy was performed according to protocol.
Irritation: On Day 3 (3-4 hours after treatment), the skin reactions were assessed. Skin reactions were graded according to the
numerical scoring system described in 'Any other information on materials and methods incl. tables'. Furthermore descriptions of
all other (local) effects were recorded.
Positive control substance(s):
other: The results of a reliability test with Alpha-hexylcinnamicaldehyde, performed not more than 6 months previously, are summarized in the attached document 'Reliability check'.
Not performed.

Results and discussion

Positive control results:
The six-month reliability check with Alpha-hexylcinnamicaldehyde indicates that the Local Lymph Node Assay as performed at NOTOX is an appropriate model for testing for contact hypersensitivity. See attached document 'Reliability check'.

In vivo (LLNA)

Resultsopen allclose all
Test Substance 10% w/w
ca. 2.1
+/- 0.4
Test group / Remarks:
Group 2 of 5 females
Test substance 25% w/w
ca. 5
+/- 0.9
Test group / Remarks:
Group 3 of 5 females
Test substance 50% w/w
ca. 28.9
+/- 5.9
Test group / Remarks:
Group 4 of 5 females
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 1133, 2691 and 15664 DPM respectively. The mean DPM/animal value for the vehicle control group was 541 DPM.
ca. 14.7
Test group / Remarks:
4 groups of five females

Any other information on results incl. tables

Preliminary irritation study:

No or slight irritation and no signs of systemic toxicity were observed in any of the animals examined. Based on these results, the highest test substance concentration selected for the main study was a 50% concentration.

Applicant's summary and conclusion

Interpretation of results:
Migrated information
The results indicate that the test substance could elicit an SI ≥ 3. The data showed a dose-response and an EC3 value (the estimated test substance concentration that will give a SI =3) of 14.7% was calculated.

Based on these results:
- according to the recommendations made in the test guidelines, Saccharomyces cerevisiae, Extract would be regarded as skin sensitizer.
- according to the Globally Harmonized System of Classification and Labeling of Chemicals (GHS) of the United Nations (2007), Saccharomyces cerevisiae, Extract should be classified as skin sensitizer (Category 1).
- according to the Regulation (EC) No 1272/2008 on classification, labelling and packaging of substances and mixtures, Saccharomyces cerevisiae, Extract should be classified as skin sensitizer (Category 1) and labeled as H317: May cause an allergic skin reaction.
- according to the EC criteria for classification and labelling requirements for dangerous substances and preparations (Council Directive 67/548/EEC), Saccharomyces cerevisiae, Extract should be labeled as: may cause sensitization by skin contact (R 43).