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Description of key information

Key value for chemical safety assessment

Skin sensitisation

Link to relevant study records
Reference
Endpoint:
skin sensitisation: in vivo (LLNA)
Type of information:
experimental study
Adequacy of study:
key study
Study period:
28 February - 20 March 2006
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: GLP study conducted in compliance with OECD guideline 429 without any deviation
Reason / purpose:
reference to same study
Reason / purpose:
reference to other study
Qualifier:
according to
Guideline:
OECD Guideline 429 (Skin Sensitisation: Local Lymph Node Assay)
Deviations:
no
Qualifier:
according to
Guideline:
EU Method B.42 (Skin Sensitisation: Local Lymph Node Assay)
Version / remarks:
version of April 24th, 2004
Deviations:
no
Principles of method if other than guideline:
Not applicable
GLP compliance:
yes
Type of study:
mouse local lymph node assay (LLNA)
Species:
mouse
Strain:
other: CBA/J
Sex:
female
Details on test animals and environmental conditions:
TEST ANIMALS- Source: Janvier, Le Genest-Saint-Isle, France- Age at study initiation: 10 weeks- Weight at study initiation: 20.7 ± 1.1 g- Housing: Individually in disposable crystal polystyrene cages- Diet (e.g. ad libitum): SsniffR/M-H pelleted diet (SSNIFF Spezialdiäten GmbH, Soest, Germany), ad libitum- Water (e.g. ad libitum): Tap water (filtered using a 0.22 µ filter), ad libitum- Acclimation period: At least 5 daysENVIRONMENTAL CONDITIONS- Temperature: 22 ± 2 °C- Humidity: 30-70 %- Air changes: Approximately 12 cycles/h of filtered, non-recycled air- Photoperiod: 12 h dark / 12 h light
Vehicle:
methyl ethyl ketone
Remarks:
Batch No 31125-303 from Aldrich, Saint-Quentin-Fallavier, France
Concentration:
Main experiment: 0.1, 0.25, 0.5, 1.0 and 2.5 % (w/v)
No. of animals per dose:
Preliminary tests: One female/doseMain experiment: Four females/dose
Details on study design:
RANGE FINDING TESTS:- Compound solubility: Due to the unsatisfactory solubility of the test item in the first recommended vehicle (acetone/olive oil (4/1, v/v)) and dimethylformamide, methyl ethyl ketone was chosen from the other proposed vehicles.- Irritation and lymph node proliferation response: A preliminary test was performed as follows: the test item was prepared at the concentrations of 10, 25, 50 and 100 % (w/v) in the first assay and at 1, 2.5, 5 and 10 % (w/v) in the complementary assay. For 3 consecutive days, the animals received applications of 25 μL of the dosage form preparations to the external surface of both ears (one concentration per ear). A gentle massage was performed in order to facilitate the application of the undiluted test item only. Measurement of the ear thickness (using a micrometer) was performed each day before treatment and 24 h after the application (first assay), or 72 h after the last application (complementary assay).MAIN STUDYANIMAL ASSIGNMENT AND TREATMENT- Name of test method: Local Lymph Node Assay- Criteria used to consider a positive response: The test item was considered as a skin sensitizer when the SI for a dose group is ≥ 3. Other relevant criteria such as cellularity, radioactivity levels and ear thickness were also taken into account for the interpretation of results. TREATMENT PREPARATION AND ADMINISTRATION: 25 µL of test material at concentrations of 0 (vehicle control), 0.1, 0.25, 0.5, 1.0, 2.5 % (w/v) in methyl ethyl ketone were applied to the dorsal surface of each ear on Days 1, 2 and 3. On Day 6, 250 μL of 0.9 % NaCl containing 20 μCi of [3H] methyl-thymidine (specific activity: 25 Ci/mmol) was injected into the tail vein of each experimental mouse. Five hours later, all mice were killed by cervical dislocation and the draining auricular lymph node of each ear was excised. A single cell suspension of auricular lymph node cells (ALNC) was prepared by mechanical disaggregation in Petri dishes with the plunger of a syringe. Cell suspensions were washed with 15 mL of 0.9 % NaCl and pellets obtained were re-suspended in 0.9 % NaCl for numeration of lymphocytes (cellularity) and determination of their viability by exclusion of trypan blue. Each cell suspension was then centrifuged and pellets were precipitated with 3 mL of 5 % (w/v) trichloroacetic acid (TCA) in purified water at +4 °C overnight. After a last centrifugation, the pellets were precipitated with 1 mL of 5 % TCA. Three mL of Ultima GoldxR scintillation fluid (Packard) were added in order to measure incorporation of 3H-TdR using β-scintillation counting. The results were expressed as disintegrations per min (dpm) per group and per node and Stimulation Indices (SI) were calculated.
Positive control substance(s):
hexyl cinnamic aldehyde (CAS No 101-86-0)
Statistics:
No data
Positive control results:
- Mean DPM = 3776.29- Stimulation index = 23.94
Parameter:
SI
Remarks on result:
other: Stimulation index for 0.1, 0.25, 0.5, 1.0 and 2.5 % (w/v) CHIMEXANE HB were calculated to be 0.78, 2.04, 4.42, 10.95 and 22.25, respectively.
Parameter:
other: disintegrations per minute (DPM)
Remarks on result:
other: Mean DPM for 0, 0.1, 0.25, 0.5, 1.0 and 2.5 % (w/v) CHIMEXANE HB were calculated to be 157.71, 122.55, 322.11, 697.54, 1726.5 and 3508.91 dpm, respectively.

Preliminary test:

Test item was found to be irritant in the first preliminary test at the concentrations of 10, 25, 50 and 100 % (w/v). A complementary preliminary test was therefore performed at the following lower concentrations: 1, 2.5, 5 and 10 % (w/v). In the complementary preliminary test, the test item was irritant at the concentrations of 5 and 10 % (w/v). The highest tested concentration retained for the main test was therefore 2.5 % (w/v).

 

Main test:

- Clinical examinations: No mortality and no clinical signs were observed during the study. The body weight change of treated animals was similar to that of control animals.

- Local irritation: An erythema was noted on Day 6 in 1/4 animals at the concentration of 0.1 % (w/v) and, in association with dryness of the skin, in all animals at the concentration of 2.5 % (w/v). No increase in ear thickness was observed in the animals of the treated groups.

 

Table 7.4.1: Results of skin sensitization:

Treatment and concentrations

No. of nodes per group

dpm per group

dpm per node

Stimulation index (SI)

Increase in ear thickness (% between Day 1 and Day 6)

Irritation level

EC3 value

Vehicle

8

157.71

19.71

-

-0.98

-

-

0.1 %

8

122.55

15.32

0.78

-1.98

0.35%

0.25 %

8

322.11

40.26

2.04

2.04

0.5 %

8

697.54

87.19

4.42

4.42

1.0 %

8

1726.50

215.81

10.95

0.99

2.5%

8

3508.91

438.61

22.25

1.92

HCA 25 %

8

3776.29

472.04

23.94

-

-

-

                            

dpm = disintegrations per minute

I = non-irritant (increase in ear thickness < 10 %)

HCA = α-hexylcinnamaldehyde

EC3 value = theoretical concentration resulting in a SI value of

stimulation index = dpm of treated group / dpm of control group

Interpretation of results:
sensitising
Remarks:
Migrated informationCriteria used for interpretation of results: EU
Conclusions:
Under the test conditions, CHIMEXANE HB is classified as ‘R43 May cause sensitisation by skin contact’, according to the criteria of Annex VI to the Directive 67/548/EEC and ‘Category 1’ according to the CLP Regulation (EC) N° (1272-2008).
Executive summary:

In a GLP-compliant local lymph node assay performed according to OECD guideline 429, CBA/J mice (4 females/dose) received 25 µL of CHIMEXANE HB at concentrations of 0 (vehicle control), 0.1, 0.25, 0.5, 1.0 and 2.5 % (w/v) in methyl ethyl ketone or of the positive control (alpha-hexylcinnamaldehyde (25 % v/v) in methyl ethyl ketone) to the dorsal surface of each ear for three consecutive days. On Day 6, all animals were injected with [3H] methyl-thymidine and after five hours the draining (auricular) lymph nodes were excised and measured for radioactivity expressed as a number of disintegrations per minute (DPM).

 

Mean DPM for 0, 0.1, 0.25, 0.5, 1.0 and 2.5 % (w/v) CHIMEXANE HB were 157.71, 122.55, 322.11, 697.54, 1726.5 and 3508.91, respectively. Stimulation index for 0.1, 0.25, 0.5, 1.0 and 2.5 % (w/v) CHIMEXANE HB were 0.78, 2.04, 4.42, 10.95 and 22.25, respectively. The estimated concentration giving rise to a 3 fold increase in lymphocyte proliferation (EC3) was 0.35 % (w/v).

An erythema was noted on Day 6 in 1/4 animals at the concentration of 0.1 % and, in association with dryness of the skin, in all animals at the concentration of 2.5 %. No increase in ear thickness was observed in the animals of the treated groups. As a moderate increase in cellularity and a stimulation index > 3 (SI = 23.94) were noted in the postive control group, the study was considered valid.

 

Under the test conditions, CHIMEXANE HB is classified as ‘R43 May cause sensitisation by skin contact’, according to the criteria of Annex VI to the Directive 67/548/EEC and ‘Category 1’ according to the CLP Regulation (EC) N° (1272-2008).

Endpoint conclusion
Endpoint conclusion:
adverse effect observed (sensitising)
Additional information:

In a GLP-compliant local lymph node assay performed according to OECD guideline 429 in 2009, CBA/J mice (4 females/dose) received 25 µL of either the test item 1667, the vehicle alone (acetone/olive oil (4/1, v/v)) or the positive control (Alpha-hexylcinnamaldehyde 25% (v/v) in acetone/olive oil (4/1, v/v)) on the dorsal surface of each ear for three consecutive days in two independent experiments. In experiment 1, the test item was tested at the concentrations of 0.1, 0.25, 0.5, 1.0 and 2.5 % (w/v); and at the concentrations of 0.25, 0.5, 1.0, 1.5 and 2.5 % (w/v) in experiment 2. On Day 6, all animals were injected with [3H] methyl-thymidine and after five hours the draining (auricular) lymph nodes were excised and measured for radioactivity expressed as a number of disintegrations per minute (DPM).

In both experiments, no mortality and no clinical signs were observed during the study. Animal body weight was not affected by treatment. In the positive control group, a moderate increase in cellularity and a stimulation index > 3 (SI = 23.94) were noted. The study was therefore considered valid.

In experiment 1, stimulation indices were 0.90, 0.46, 2.94, 2.21 and 6.73 at 0.1, 0.25, 0.5, 1.0 and 2.5 % (w/v) test material, respectively. An erythema and a dryness of the skin of the ears were noted in all the animals treated at the concentration of 2.5 % (w/v). A slightly increase in ear thickness was observed in these animals. In experiment 2, stimulation indexes were 1.07, 1.66, 2.03, 6.24 and 6.54 at 0.25, 0.5, 1.0, 1.5 and 2.5 % (w/v) test material, respectively. A dryness of the skin was noted on Day 6 in 2/4 animals treated at the concentration of 0.5 % (w/v) and in all the animals treated at the concentration of 1 and 1.5 % (w/v). An erythema and a dryness of the skin of the ears were noted in all the animals treated at the concentration of 2.5 % (w/v). A slightly increase in ear thickness was observed in these animals. The EC3 values in experiments 1 and 2 were calculated to be 1.3 and 1.1 % (w/v), respectively.

In another GLP-compliant local lymph node assay performed according to OECD guideline 429 in 2006, groups of CBA/J mice (4 females/dose) received 25 µL of CHIMEXANE HB at concentrations of 0 (vehicle control), 0.1, 0.25, 0.5, 1.0 and 2.5 % (w/v) in methyl ethyl ketone or of the positive control (alpha-hexylcinnamaldehyde (25 % v/v) in methyl ethyl ketone) to the dorsal surface of each ear for three consecutive days. On Day 6, all animals were injected with [3H] methyl-thymidine and after five hours the draining (auricular) lymph nodes were excised and measured for radioactivity expressed as a number of disintegrations per minute (DPM).

No clinical signs and no mortality were observeed during the study. Stimulation index for 0.1, 0.25, 0.5, 1.0 and 2.5 % (w/v) CHIMEXANE HB were 0.78, 2.04, 4.42, 10.95 and 22.25, respectively. The estimated concentration giving rise to a 3 fold increase in lymphocyte proliferation (EC3) was 0.35 % (w/v). An erythema was noted on Day 6 in 1/4 animals at the concentration of 0.1 % and, in association with dryness of the skin, in all animals at the concentration of 2.5 %. No increase in ear thickness was observed in the animals of the treated groups. As a moderate increase in cellularity and a stimulation index > 3 (SI = 23.94) were noted in the postive control group, the study was considered valid.

 

 

Migrated from Short description of key information:

In two LLNA, Chimexane HB induced skin sensitization with EC3 values of 0.35% and 1.1%.

Justification for selection of skin sensitisation endpoint:

GLP-compliant study with a Klimish 1, which presents the lowest EC3 value.

Respiratory sensitisation

Endpoint conclusion
Endpoint conclusion:
no study available

Justification for classification or non-classification

As Chimexane HB induced positive responses in two LLNA with EC3 values of 0.35% and 1.1%, it is classified "R43: May cause sensitisation by skin contact" according to the Annex VI to the Directive 67/548/EEC and skin sensitiser Category 1 according to the Regulation (EC) N° 1272-2008 (CLP).