Registration Dossier

Toxicological information

Skin sensitisation

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Administrative data

Endpoint:
skin sensitisation: in vivo (non-LLNA)
Type of information:
read-across from supporting substance (structural analogue or surrogate)
Remarks:
Summary of available data used for the endpoint assessment of the target substance
Adequacy of study:
key study
Justification for type of information:
refer to analogue justification provided in IUCLID section 13
Cross-referenceopen allclose all
Reason / purpose:
read-across source
Reference
Endpoint:
skin sensitisation: in vivo (non-LLNA)
Type of information:
experimental study
Adequacy of study:
disregarded due to major methodological deficiencies
Reliability:
3 (not reliable)
Rationale for reliability incl. deficiencies:
other: insufficient for assessment: o-cresol only used in the re-challenge experiment
Principles of method if other than guideline:
GPMT was first performed with 2-methylol phenol, then re-challenge was performed with 13.1 w/w% o-cresol in ethanol
GLP compliance:
not specified
Type of study:
guinea pig maximisation test
Justification for non-LLNA method:
Test was done before LLNA as first-choice method for in-vivo testing was set into force.
Species:
guinea pig
Strain:
Dunkin-Hartley
Sex:
female
Details on test animals and environmental conditions:
no data
Route:
intradermal
Vehicle:
other: ethanol
Concentration / amount:
2-methylol phenol: 5% w/v; SLS: 10% w/v
Route:
other: epicutaneous
Concentration / amount:
2-methylol phenol: 25% w/v
No.:
#1
Concentration / amount:
2-methylol phenol: 15%
No.:
#2
Concentration / amount:
o-cresol: 13.1%
No. of animals per dose:
no data
Details on study design:
according to Magnusson and Kligman, J. Invest Dermatol. (1969), 52, 268-276
Challenge controls:
yes
Positive control substance(s):
not specified

Guinea pigs sensitized with 2-methylol phenol showed skin effects also with o-cresol (13.1%). Control group animals also showed skin effects, therefore the used test concentration was probably irritating.

Interpretation of results:
study cannot be used for classification
Conclusions:
Guinea pigs sensitized with 2-methylol phenol showed skin effects also with o-cresol (13.1%). Control group animals also showed skin effects, therefore the used test concentration was probably irritating.
Reason / purpose:
read-across source
Reference
Endpoint:
skin sensitisation: in vivo (non-LLNA)
Type of information:
experimental study
Adequacy of study:
weight of evidence
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
comparable to guideline study with acceptable restrictions
Remarks:
small number of animals tested; reactions should have been scored additionally at 48 hours
Qualifier:
equivalent or similar to
Guideline:
OECD Guideline 406 (Skin Sensitisation)
Deviations:
yes
Remarks:
The equivalent total dose was administered on one occasion as 4 intradermal injections, each 2.5 times the Injection Challenge Concentration (ICC)
GLP compliance:
not specified
Type of study:
Draize test
Justification for non-LLNA method:
Test was done before LLNA as first-choice method for in-vivo testing was set into force.
Species:
guinea pig
Strain:
Hartley
Sex:
male/female
Details on test animals and environmental conditions:
TEST ANIMALS
- Weight at study initiation: 350 g
- Housing: 2/per cage, same sex
- Diet ad libitum
- Water ad libitum


Route:
intradermal
Vehicle:
not specified
Concentration / amount:
0.1%
No.:
#1
Route:
intradermal
Vehicle:
not specified
Concentration / amount:
10%
No.:
#2
Route:
other: epicutaneous
Vehicle:
not specified
Concentration / amount:
10%
No. of animals per dose:
10
Details on study design:
10 guinea pigs (4 males and 6 females or vice versa). Both flanks of each  guinea pig were shaved, intradermal injections or topical applications were performed without occlusion. Primary irritation tests were performed to determine the suitable concentrations.

METHOD: Each animal was injected intradermally with 0.1 mL of TS at 2.5 times the determined injection challenge concentration (ICC) of 0.1%  at 4 sites which overlie the 2 auxilliary and the 2 inguinal lymph nodes. 14 days  later each animal was challenged intradermally in one flank and topically  in the
 other with 0.1 mL aliquots of TS at the respective ICC and  application challenge concentration (ACC; 10%). 24 hours later the  reactions were scored. 

To confirm the result, the procedure was repeated  including a confirmatory challenge with controls.

1st application: Induction 0.1 % intracutaneous
2nd application: Challenge 10 % intracutaneous
3rd application: Challenge 10 % other: topical application

Challenge controls:
At each challenge with controls 4 previously untreated animals of the same sex and similar weight to the test animals were treated intradermally and topically on opposite flanks with 0.1 mL aliquots of test substance at the ICC and ACC respectively.
Positive control substance(s):
not specified
Positive control results:
no data
Key result
Reading:
other: no details given
Hours after challenge:
24
Group:
other: no details given
Dose level:
0.1 %
No. with + reactions:
0
Total no. in group:
10
Clinical observations:
no data
Interpretation of results:
other: CLP/EU GHS criteria are not met, no classification required according to Regulation (EC) No 1272/2008
Conclusions:
p-cresol did not reveal sensitizing potency in a modified Draize test with guinea pigs.
Reason / purpose:
read-across source
Reference
Endpoint:
skin sensitisation: in vivo (non-LLNA)
Type of information:
experimental study
Adequacy of study:
weight of evidence
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Qualifier:
according to
Guideline:
OECD Guideline 406 (Skin Sensitisation)
GLP compliance:
yes
Type of study:
guinea pig maximisation test
Justification for non-LLNA method:
Test was done before LLNA as first-choice method for in-vivo testing was set into force.
Species:
guinea pig
Strain:
Pirbright-Hartley
Sex:
female
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: Charles River GmbH, Wiga, Kisslegg, FRG
- Age at study initiation: Young adult
- Weight at study initiation: 322 -399 g
- Housing: 5/cage
- Diet: Kliba Labordiaet (kninchen-Meerschweinchen-Haltungsdiaet), ad libitum
- Water: tap water, ad libitum
- Acclimation period: 7 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 21 - 25 ˚C
- Humidity (%): 30 - 70%
- Air changes (per hr): not stated
- Photoperiod (hrs dark / hrs light): 12 / 12
Route:
intradermal
Vehicle:
other: Lutrol E 400 DAB
Concentration / amount:
0.5%
Route:
other: epicutaneous
Vehicle:
other: Lutrol E 400 DAB
Concentration / amount:
25%
No.:
#1
Route:
epicutaneous, occlusive
Vehicle:
other: Lutrol E 400 DAB
Concentration / amount:
5%
No.:
#2
Route:
epicutaneous, occlusive
Vehicle:
other: Lutrol E 400 DAB
Concentration / amount:
5%
No. of animals per dose:
20 animals/test group
10 animals/control group - 2 control groups
Details on study design:
RANGE FINDING TESTS:
Intradermal induction using adjuvant technique:
6 injections in groups of 2 animal/test concentration were applied (front row: 0.1 mL Freund's adjuvant (without test substance), emulsified with 0.9% NaCl(aq) solution in a ratio of 1:1; middle row: 0.1 mL of test substance formulation (0.5%) in Lutrol E 400 DAB: back row: 0.1 mL test substance formulation (0.5%) in Freund's adjuvant / 0.9% NaCl(aq)). Readings were taken 24 hrs after the beginining of application.

Percutaneous induction:
2 x 2 cm filter paper strips containing the test substance formulation were applied to the skin of the flanks under an occulsive dressing. The test substance was applied twice for 24 hrs within a period of 96 hrs. 4 animals/test concentration were used and readings were taken at 24 and 48 hrs after the begining of the application.

MAIN STUDY
10 animals/control group and 20 animals/test substance group. Intradermal induction with a solution of Freund's adjuvant in physiological saline solution containing 0.5% 2,4-xylenol. One week later percutaneous induction was carried out using a 25% solution of 2,4-xylenol in Lutrol E 400 DAB. Controls were treated with Lutrol alone.14 days later animals were challenged. One control group (along with the test group) had a 5% solution of 2,4-xylenol in Lutrol E 400 DAB applied to elicit a skin reaction. The 2nd control group was treated with Lutrol E 400 alone.

A second challenge was carried out 1 week later, with all animals including the 2 control groups treated with 5% solution of 2,4-xylenol in Lutrol E 400 DAB.

OTHER:
Insufficient detail was contained in the summary report concerning food and water consumption, frequency of clinical observations, body weight records etc.

Statistical analysis:
Assumed none, as no statistics were reported in the summary report

Assessment of skin findings:
Pre-test
1. Erytherma and eschar formation:
a) No erythema = 0
b) Very slight erythema = 1
c) Well-defined erythema = 2
d) Moderate to severe erythema = 3
e) Sever erythema to slight eschar formation = 4

2. Oedema formation:
a) No oedema = 0
b) Very slight oedema = 1
c) Well-defined oedema = 2
d) Moderate to severe oedema = 3
e) Severe oedema = 4

Main test:
0 = visible change
1 = discrete or patchy erythema
2 = moderate and confluent erythema
3 = intense erythema and swelling
Reading:
1st reading
Hours after challenge:
24
Group:
negative control
Dose level:
Lutrol E 400 DAB
No. with + reactions:
0
Total no. in group:
10
Reading:
2nd reading
Hours after challenge:
48
Group:
negative control
Dose level:
Lutrol E 400 DAB
No. with + reactions:
0
Total no. in group:
10
Reading:
1st reading
Hours after challenge:
24
Group:
negative control
Dose level:
5% in Lutrol E 400 DAB
No. with + reactions:
0
Total no. in group:
10
Reading:
2nd reading
Hours after challenge:
48
Group:
negative control
Dose level:
5% in Lutrol E 400 DAB
No. with + reactions:
0
Total no. in group:
10
Key result
Reading:
1st reading
Hours after challenge:
24
Group:
test group
Dose level:
5% in Lutrol E 400 DAB
No. with + reactions:
11
Total no. in group:
20
Clinical observations:
discrete or patchy eythema; moderate and confluent erythema or intense erythema and swelling
Key result
Reading:
2nd reading
Hours after challenge:
48
Group:
test group
Dose level:
5% in Lutrol E 400 DAB
No. with + reactions:
9
Total no. in group:
20
Clinical observations:
discrete or patchy erythema; moderate and confluent erythema; scaling
Reading:
rechallenge
Hours after challenge:
24
Group:
negative control
Dose level:
Lutrol E 400 DAB
No. with + reactions:
0
Total no. in group:
10
Reading:
rechallenge
Hours after challenge:
48
Group:
negative control
Dose level:
5% in Lutrol E 400 DAB
No. with + reactions:
0
Total no. in group:
10
Key result
Reading:
rechallenge
Hours after challenge:
24
Group:
test group
Dose level:
5% in Lutrol E 400 DAB
No. with + reactions:
8
Total no. in group:
20
Clinical observations:
discrete or patchy erythema
Key result
Reading:
rechallenge
Hours after challenge:
48
Group:
test group
Dose level:
5% in Lutrol E 400 DAB
No. with + reactions:
6
Total no. in group:
20
Clinical observations:
discrete or patchy erythema

Results:

Intradermal induction, moderate and confluent erythema and swelling were observed at the injection sites of all control group animals and all test group animals at which only Freund's adjuvant in NaCl was applied. Necrotic changes and swelling were observed in the other sites (Lutrol E 400 DAB and 50% Lutrol with FCA / 0.9% NaCl(aq)).

Injections with 0.5% test substance in Lutrol E 400 DAB also caused swelling and necrotic skin changes. Moderate and confluent erythema and swelling were observed at the injection sites of all test group animals which were applied with a 0.5% test substance preparation in FCA/0.9% NaCl (aq).

Percutaneous induction (1 week later): Controls treated with Lutrol E 400 (no reaction). Induction with 2,4-xylenol (25% in Lutrol E 400 DAB) gave rise to swelling and necrotic skin changes.

1st challenge (14 days later): No findings in all control animals at 24 or 48hrs.

Test animals 24hrs: 1/20 intense erythema and swelling; 8/20 moderate and confluent erythema; 2/20 discrete or patchy erythema.

Test animals 48hrs: 4/20 moderate and confluent erythema; 3/20 discrete or patchy erythema.2/20 dscrete or patchy erythema as well as scaling

2nd challenge (1 week later): No findings in all control animals at 24 or 48hrs.

Test animals 24hrs: 4/20 moderate and confluent erythema; 4/20 discrete or patchy erythema.

Test animals 48hrs: 1/20 moderate and confluent erythema; 5/20 discrete or patchy erythema

Challenge and rechallenge results presented above.

Table 1: 1st Control group - intradermal induction:

Form of application

A. Freund’s adjuvant / 0.9% NaCl (aq) 1:1

B Lutrol E 400 DAB

C 50% preparation of Lutrol E 400 DAB with Freund’s adjuvant / 0.9% NaCl (aq) 1:1

Animal

11

12

13

14

15

16

17

18

19

20

24hr

R

L

R

L

R

L

R

L

R

L

R

L

R

L

R

L

R

L

R

L

 

A

2E

2E

2E

2E

2E

2E

2E

2E

2E

2E

2E

2E

2E

2E

2E

2E

2E

2E

2E

2E

B

NE

NE

NE

NE

NE

NE

NE

NE

NE

NE

NE

NE

NE

NE

NE

NE

NE

NE

NE

NE

C

NE

NE

NE

NE

NE

NE

NE

NE

NE

NE

NE

NE

NE

NE

NE

NE

NE

NE

NE

NE

Table 2: 2nd Control group - intradermal indcution:

Form of application

A. Freund’s adjuvant / 0.9% NaCl (aq) 1:1

B Lutrol E 400 DAB

C 50% preparation of Lutrol E 400 DAB with Freund’s adjuvant / 0.9% NaCl (aq) 1:1

Animal

21

22

23

24

25

26

27

28

29

30

24hr

R

L

R

L

R

L

R

L

R

L

R

L

R

L

R

L

R

L

R

L

 

A

2E

2E

2E

2E

2E

2E

2E

2E

2E

2E

2E

2E

2E

2E

2E

2E

2E

2E

2E

2E

B

NE

NE

NE

NE

NE

NE

NE

NE

NE

NE

NE

NE

NE

NE

NE

NE

NE

NE

NE

NE

C

NE

NE

NE

NE

NE

NE

NE

NE

NE

NE

NE

NE

NE

NE

NE

NE

NE

NE

NE

NE

 

Table 3: Test group - intradermal induction:

Form of application

A. Freund’s adjuvant / 0.9% NaCl (aq) 1:1

B Test substance 0.5% in Lutrol E 400 DAB

C Test substance 0.5% in Freund’s adjuvant / 0.9% NaCl (aq) 1:1

Animal

31

32

33

34

35

36

37

38

39

40

24hr

R

L

R

L

R

L

R

L

R

L

R

L

R

L

R

L

R

L

R

L

 

A

2E

2E

2E

2E

2E

2E

2E

2E

2E

2E

2E

2E

2E

2E

2E

2E

2E

2E

2E

2E

B

NE

NE

NE

NE

NE

NE

NE

NE

NE

NE

NE

NE

NE

NE

NE

NE

NE

NE

NE

NE

C

2E

2E

2E

2E

2E

2E

2E

2E

2E

2E

2E

2E

2E

2E

2E

2E

2E

2E

2E

2E

Form of application

A. Freund’s adjuvant / 0.9% NaCl (aq) 1:1

B Test substance 0.5% in Lutrol E 400 DAB

C Test substance 0.5% in Freund’s adjuvant / 0.9% NaCl (aq) 1:1

Animal

41

42

43

44

45

46

47

48

49

50

24hr

R

L

R

L

R

L

R

L

R

L

R

L

R

L

R

L

R

L

R

L

 

A

2E

2E

2E

2E

2E

2E

2E

2E

2E

2E

2E

2E

2E

2E

2E

2E

2E

2E

2E

2E

B

NE

NE

NE

NE

NE

NE

NE

NE

NE

NE

NE

NE

NE

NE

NE

NE

NE

NE

NE

NE

C

2E

2E

2E

2E

2E

2E

2E

2E

2E

2E

2E

2E

2E

2E

2E

2E

2E

2E

2E

2E

R = right

L = left

2 = Moderate and confluent erythema

E = swelling

N = necrotic skin changes

Table 4: 1st Control group - percutaneous induction

Form of application: Lutrol E 400 DAB

 

Animal

11

12

13

14

15

16

17

18

19

20

48hr

NE

NE

NE

NE

NE

NE

NE

NE

NE

NE

 

Table 5: 2nd Control group - percutaneous induction

Form of application: Lutrol E 400 DAB

 

Animal

21

22

23

24

25

26

27

28

29

30

48hr

NE

NE

NE

NE

NE

NE

NE

NE

NE

NE

Table 6: Test group - percutaneous induction

Form of application: Test substance 25% in Lutrol E 400 DAB

 

Animal

31

32

33

34

35

36

37

38

39

40

48hr

NE

NE

NE

NE

NE

NE

NE

NE

NE

NE

Form of application: Test substance 25% in Lutrol E 400 DAB

 

Animal

41

42

43

44

45

46

47

48

49

50

48hr

NE

NE

NE

NE

NE

NE

NE

NE

NE

NE

Interpretation of results:
other: CLP/EU GHS Category 1B (H317) according to Regulation (EC) No 1272/2008
Conclusions:
A clear sensitising effect was observed for 2,4-xylenol when investigated in guinea pigs in the Maximisation test.
Executive summary:

In a dermal sensitization study, guinea pigs (20/sex) received intradermal injections of 0.5% 2,4-xylenol (administered in Lutrol E 400 DAB and Freund’s Complete Adjuvant (FCA)) / 0.9% NaCl (1:1)). The treatment regime involved induction of sensitization by intradermal injection on day 1, induction of sensitization by topical administration one week later (25% 2,4-xylenol in Lutrol E 400 DAB), challenge by topical administration on day 21 (5% 2,4-xylenol in Lutrol E 400 DAB), followed by a rechallenge on day 28 (5% 2,4-xylenol in Lutrol E 400 DAB).

Following intradermal induction, 0.5% 2,4 xylenol caused swelling and moderate erythema. One week later percutaneous induction with 25% 2,4-xylenol in Lutrol E 400 DAB resulted in swelling and necrotic changes. Following challenge, 11/20 test animals showed a positive allergic reaction. Following rechallenge 8/20 test animals showed a positive allergic reaction. The 5% 2,4-xylenol applied to control animals was tolerated and no skin reactions were observed in the control groups.

2,4-xylenol showed a clear skin sensitisation potential in this study.

Reason / purpose:
read-across source
Reference
Endpoint:
skin sensitisation: in vivo (non-LLNA)
Type of information:
experimental study
Adequacy of study:
weight of evidence
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Qualifier:
according to
Guideline:
OECD Guideline 406 (Skin Sensitisation)
Qualifier:
according to
Guideline:
EU Method B.6 (Skin Sensitisation)
GLP compliance:
yes
Type of study:
guinea pig maximisation test
Justification for non-LLNA method:
Test was done before LLNA as first-choice method for in-vivo testing was set into force.
Species:
guinea pig
Strain:
Pirbright-Hartley
Sex:
female
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: Charles River GmbH, Wiga
- Age at study initiation: young adult animals
- Weight at study initiation: 332 -380 g
- Housing: 5 animals/sex
- Diet: Kliba Labordiaet,ad libitum
- Water: tap water,ad libitum
- Acclimation period: 7 days


ENVIRONMENTAL CONDITIONS
- Temperature (°C): 21 - 25˚C
- Humidity (%): 30 - 70%
- Air changes (per hr): not stated
- Photoperiod (hrs dark / hrs light): 12 / 12
Route:
intradermal
Vehicle:
other: Lutrol E400 DAB
Concentration / amount:
1%
Adequacy of induction:
not specified
Route:
other: epicutaneous
Vehicle:
other: Lutrol E 400 DAB
Concentration / amount:
5%
Adequacy of induction:
not specified
No.:
#1
Route:
epicutaneous, occlusive
Vehicle:
other: Lutrol E400 DAB
Concentration / amount:
0.5%
Adequacy of challenge:
not specified
No.:
#2
Route:
epicutaneous, occlusive
Vehicle:
other: Lutrol E 400 DAB
Concentration / amount:
0.5%
Adequacy of challenge:
not specified
No. of animals per dose:
20 animals/test group
10 animals/control group - 2 control groups
Details on study design:
RANGE FINDING TESTS: The concentrations of the test substance suitable for use in the main experiment were determined in the pretest.

Intradermal induction using adjuvant technique:
6 injections in groups of 2 animal/test concentration were applied (front row: 0.1 mL Freund's adjuvant (without test substance), emulsified with 0.9% NaCl(aq) solution in a ratio of 1:1; middle row: 0.1 mL of test substance formulation (0.5%) in Lutrol E 400 DAB: back row: 0.1 mL test substance formulation (0.5%) in Freund's adjuvant / 0.9% NaCl(aq)). Readings were taken 24 hrs after the beginining of application.

Percutaneous induction:
2 x 2 cm filter paper strips containing the test substance formulation were applied to the skin of the flanks under an occlusive dressing. The test substance was applied twice for 24 hrs within a priod of 96 hrs. 4 animals/test concentration were used and readings were taken at 24 and 48 hrs after the beginning of the application.

Main test:
10 animals/control group and 20 animals/test substance group. Injections for the main test intradermal induction were the same as the pre-test and read 24 hrs post application. Percutaenous induction was conducted about 1 week post the intradermal induction. 4 x 2 cm gauze patches containing the test substance formulation were applied to the skin of the shoulder under an occlusive dressing. Duration of exposure was 48 hrs, and readings were taken at the end of the exposure period.
The first challenge was performed 21 days post the intradermal induction. A 2nd challenge was carried out 1 week after the first. In both cases a 2 x 2 cm gauze patches were applied to the skin of the flank under an occulsive dressing. For the 1st challenge test group and control group 1 were treated with the test substance formulation. Additionally, Lutrol E 400 DAB was applied as a vehicle control. Control group 2 only received Lutrol E 400 DAB. For the 2nd challenge, test group and control groups 1 and 2 were treated with the test substance formulations.
Duration of exposure was 24 hrs and readings were taken 24 and 48 hrs post patch removal.


OTHER:
Animals were randomised according to Salfi, R (A long period randon number generator with application to permutation. Compstat, 1974 pg 24 -35).

Twice daily check (weekdays) or once daily check (weekends) for dead or moribund animals was made.
Body weights: Prior to dosing and at the end of the study
Food consumption: not determined
Water consumption: not determined

Statistical analysis: None

Assessment of skin findings:
Pre-test
1. Erytherma and eschar formation:
a) No erythema = 0
b) Very slight erythema = 1
c) Well-defined erythema = 2
d) Moderate to severe erythema = 3
e) Sever erythema to slight eschar formation = 4

2. Oedema formation:
a) No oedema = 0
b) Very slight oedema = 1
c) Well-defined oedema = 2
d) Moderate to severe oedema = 3
e) Severe oedema = 4

Main test:
0 = visible chang
1 = discrete or patchy erythema
2 = moderate and confluent erythema
3 = intense erythema and swelling
Positive control substance(s):
no
Remarks:
A positive control was not concluded. However, a reliability check was performed biannually in the laboratory using alpha-hexylcinnamaldehyde confirming suitability and specificity of the test system.
Reading:
1st reading
Hours after challenge:
24
Group:
negative control
Dose level:
Lutrol E 400 DAB
No. with + reactions:
0
Total no. in group:
10
Reading:
1st reading
Hours after challenge:
24
Group:
negative control
Dose level:
0.5% in Lutrol E 400 DAB
No. with + reactions:
0
Total no. in group:
10
Reading:
2nd reading
Hours after challenge:
48
Group:
negative control
Dose level:
Lutrol E 400 DAB
No. with + reactions:
0
Total no. in group:
10
Reading:
2nd reading
Hours after challenge:
48
Group:
negative control
Dose level:
0.5% in Lutrol E 400 DAB
No. with + reactions:
0
Total no. in group:
10
Key result
Reading:
1st reading
Hours after challenge:
24
Group:
test group
Dose level:
0.5% in Lutrol E 400 DAB
No. with + reactions:
5
Total no. in group:
20
Clinical observations:
mild and moderate erythema
Remarks on result:
other: 2/5 had also positive reaction with solvent alone applied to a separate site
Key result
Reading:
2nd reading
Hours after challenge:
48
Group:
test group
Dose level:
0.5% in Lutrol E 400 DAB
No. with + reactions:
7
Total no. in group:
20
Clinical observations:
mild and moderate erythema
Remarks on result:
other: 1/7 had also positive reaction with solvent alone applied to a separate site
Reading:
rechallenge
Hours after challenge:
24
Group:
negative control
Dose level:
Lutrol E 400 DAB
No. with + reactions:
0
Total no. in group:
10
Reading:
rechallenge
Hours after challenge:
24
Group:
negative control
Dose level:
0.5% in Lutrol E 400 DAB
No. with + reactions:
0
Total no. in group:
10
Reading:
rechallenge
Hours after challenge:
48
Group:
negative control
Dose level:
0.5% in Lutrol E 400 DAB
No. with + reactions:
0
Total no. in group:
10
Reading:
rechallenge
Hours after challenge:
48
Group:
negative control
Dose level:
Lutrol E 400 DAB
No. with + reactions:
0
Total no. in group:
10
Key result
Reading:
rechallenge
Hours after challenge:
24
Group:
test group
Dose level:
0.5% in Lutrol E 400 DAB
No. with + reactions:
1
Total no. in group:
20
Clinical observations:
mild erythema
Key result
Reading:
rechallenge
Hours after challenge:
48
Group:
test group
Dose level:
Test substance 0.5% in Lutrol E 400 DAB
No. with + reactions:
1
Total no. in group:
20
Clinical observations:
mild erythema

Challenge and rechallenge results presented above.

Table 1: 1st Control group - intradermal induction:

Form of application

A. Freund’s adjuvant / 0.9% NaCl (aq) 1:1

B Lutrol E 400 DAB

C 50% preparation of Lutrol E 400 DAB with Freund’s adjuvant / 0.9% NaCl (aq) 1:1

Animal

211

212

213

214

215

216

217

218

219

220

24hr

R

L

R

L

R

L

R

L

R

L

R

L

R

L

R

L

R

L

R

L

 

A

2E

2E

2E

2E

2E

2E

2E

2E

2E

2E

2E

2E

2E

2E

2E

2E

2E

2E

2E

2E

B

NE

NE

NE

NE

NE

NE

NE

NE

NE

NE

NE

NE

NE

NE

NE

NE

NE

NE

NE

NE

C

NE

NE

NE

NE

NE

NE

NE

NE

NE

NE

NE

NE

NE

NE

NE

NE

NE

NE

NE

NE

Table 2: 2nd Control group - intradermal indcution:

Form of application

A. Freund’s adjuvant / 0.9% NaCl (aq) 1:1

B Lutrol E 400 DAB

C 50% preparation of Lutrol E 400 DAB with Freund’s adjuvant / 0.9% NaCl (aq) 1:1

Animal

221

222

223

224

225

226

227

228

229

230

24hr

R

L

R

L

R

L

R

L

R

L

R

L

R

L

R

L

R

L

R

L

 

A

2E

2E

2E

2E

2E

2E

2E

2E

2E

2E

2E

2E

2E

2E

2E

2E

2E

2E

2E

2E

B

NE

NE

NE

NE

NE

NE

NE

NE

NE

NE

NE

NE

NE

NE

NE

NE

NE

NE

NE

NE

C

NE

NE

NE

NE

NE

NE

NE

NE

NE

NE

NE

NE

NE

NE

NE

NE

NE

NE

NE

NE

 

Table 3: Test group - intradermal induction:

Form of application

A. Freund’s adjuvant / 0.9% NaCl (aq) 1:1

B Test substance 1% in Lutrol E 400 DAB

C Test substaqnce 1% in Freund’s adjuvant / 0.9% NaCl (aq) 1:1

Animal

231

232

233

234

235

236

237

238

239

240

24hr

R

L

R

L

R

L

R

L

R

L

R

L

R

L

R

L

R

L

R

L

 

A

2E

2E

2E

2E

2E

2E

2E

2E

2E

2E

2E

2E

2E

2E

2E

2E

2E

2E

2E

2E

B

NE

NE

NE

NE

NE

NE

NE

NE

NE

NE

NE

NE

NE

NE

NE

NE

NE

NE

NE

NE

C

NE

NE

NE

NE

NE

NE

NE

NE

NE

NE

NE

NE

NE

NE

NE

NE

NE

NE

NE

NE

Form of application

A. Freund’s adjuvant / 0.9% NaCl (aq) 1:1

B Test substance 1% in Lutrol E 400 DAB

C Test substaqnce 1% in Freund’s adjuvant / 0.9% NaCl (aq) 1:1

Animal

241

242

243

244

245

246

247

248

249

250

24hr

R

L

R

L

R

L

R

L

R

L

R

L

R

L

R

L

R

L

R

L

 

A

2E

2E

2E

2E

2E

2E

2E

2E

2E

2E

2E

2E

2E

2E

2E

2E

2E

2E

2E

2E

B

NE

NE

NE

NE

NE

NE

NE

NE

NE

NE

NE

NE

NE

NE

NE

NE

NE

NE

NE

NE

C

NE

NE

NE

NE

NE

NE

NE

NE

NE

NE

NE

NE

NE

NE

NE

NE

NE

NE

NE

NE

R = right

L = left

2 = Moderate and confluent erythema

E = swelling

N = necrotic skin changes

Table 4: 1st Control group - percutaneous induction

Form of application: Lutrol E 400 DAB

 

Animal

211

212

213

214

215

216

217

218

219

220

48hr

NE

NE

NE

NE

NE

NE

NE

NE

NE

NE

 

Table 5: 2nd Control group - percutaneous induction

Form of application: Lutrol E 400 DAB

 

Animal

221

222

223

224

225

226

227

228

229

230

48hr

NE

NE

NE

NE

NE

NE

NE

NE

NE

NE

Table 6: Test group - percutaneous induction

Form of application: Test substance 5% in Lutrol E 400 DAB

 

Animal

231

232

233

234

235

236

237

238

239

240

48hr

NE

NE

NE

NE

NE

NE

NE

NE

NE

NE

Form of application: Test substance 5% in Lutrol E 400 DAB

 

Animal

241

242

243

244

245

246

247

248

249

250

48hr

NE

NE

NE

NE

NE

NE

NE

NE

NE

NE

Interpretation of results:
other: CLP/EU GHS criteria are not met, no classification required according to Regulation (EC) No 1272/2008
Conclusions:
Positive reactions after the first challenge were not confirmed in the second challenge and additionally postive skin reactions were also observed at the control site in animals which showed positive reactions after first challenge. Thus, it is concluded that 3,5 xylenol is not skin sensitising.
Executive summary:

In a dermal sensitization study, guinea pigs (20/sex) received intradermal injections of 1% 3,5 xylenol in Lutrol E 400 DAB along with injections of Freund’s Complete Adjuvant (FCA) / 0.9% NaCl (1:1) and 1% (w/v) iodomethane in FCA / 0.9% NaCl. The treatment regime involved induction of sensitization by intradermal injection on day 1, induction of sensitization by topical administration one week later (5% 3,5 xylenol in Lutrol E 400 DAB), challenge by topical administration on day 21 (0.5% 3,5 xylenol in Lutrol E 400 DAB), followed by a rechallenge on day 28 (0.5% 3,5 xylenol in Lutrol E 400 DAB).

Following intradermal injections all animals (both control groups and test group animals) showed skin reactions (FCA - moderate and confluent erythrema with swelling, for test substance in Lutrol E 400 DAB, Lutrol E 400 DAB, test substance in FCA and 50% Lutrol E 400 DAB in FCA - necrotic skin changes with swelling) to both the vehicle and test preparations.

Following challenge, dermal scores of 1 and 2 were noted in 5/20 test animals at the 24 and 7/20 at the 48 hour scoring intervals. Following rechallenge dermal scores of 1 were noted in 1/20 test animals at the 24 and 48 hour scoring intervals combined. Dermal reactions in the remaining test and rechallenge control animals were limited to scores of 0. The solvent Lutrol E 400 DAB, which was applied to a separate site as a control in all test group animals, produced the same effects as 3,5 -xylenol. At 24 hours after the first challenge, these effects were noted in 2 animals that reacted to 3,5 xylenol out of the 20 in the group while at 48 hours they were seen in 1 such animal out of 20 in the group. These findings (a positive result for the first challenge which was not confirmed by the second challenge and positive skin reactions to the vehicle itself in some animals which had reacted to 3,5 xylenol following the first challenge) leads to the conclusion that 3,5 xylenol is devoid of any skin-sensitising potential under the conditions of the sutdy.

Data source

Materials and methods

Test material

Reference
Name:
Unnamed
Type:
Constituent

Results and discussion

In vivo (non-LLNA)

Resultsopen allclose all
Key result
Reading:
1st reading
Hours after challenge:
24
Group:
test group
Dose level:
Test substance 5% in Lutrol E 400 DAB
No. with + reactions:
6
Total no. in group:
10
Clinical observations:
discrete or patchy eythema; moderate and confluent erythema
Remarks on result:
other: Source: CAS 105-67-9, 2,4-xylenol, BG Chemie, 1998, GPMT
Key result
Reading:
2nd reading
Hours after challenge:
48
Group:
test group
Dose level:
Test substance 5% in Lutrol E 400 DAB
No. with + reactions:
5
Total no. in group:
10
Clinical observations:
discrete or patchy erythema; moderate and confluent erythema
Remarks on result:
other: Source: CAS 105-67-9, 2,4-xylenol, BG Chemie, 1998, GPMT
Key result
Reading:
rechallenge
Hours after challenge:
24
Group:
test group
Dose level:
Test substance 5% in Lutrol E 400 DAB
No. with + reactions:
3
Total no. in group:
10
Clinical observations:
discrete or patchy erythema; moderate and confluent erythema
Remarks on result:
other: Source: CAS 105-67-9, 2,4-xylenol, BG Chemie, 1998, GPMT
Key result
Reading:
rechallenge
Hours after challenge:
48
Group:
test group
Dose level:
Test substance 5% in Lutrol E 400 DAB
No. with + reactions:
3
Total no. in group:
10
Clinical observations:
discrete or patchy erythema
Remarks on result:
other: Source: CAS 105-67-9, 2,4-xylenol, BG Chemie, 1998, GPMT

Any other information on results incl. tables

In the result table above the most critical value of the weight of evidence approach is given. In the following, the results are shown for the other source substances of this weight of evidence approach:

Source CAS 106-44-5: p-cresol: Draize test: 0.1% of p-cresol did not induce any reactions (0/10); Sharp, 1978

Source CAS 108 -68 -9: 3,5-xylenols: GPMT: 0.5% 3,5 -xylenol resulted in 5/20 positive reactions after 24 hours ( 2/5 had also positive reaction with solvent alone applied to a separate site), after 48 hours 7/20 positive reactions were observed (1/7 had also positive reaction with solvent alone applied to a separate site); at rechallange after 24 and 48 hours 1/20 positive reactions were observed; BG Chemie, 1999

An additional guinea pig maximisation test on source substance o-cresol (CAS 95-48-7) was available (Bruze, 1986). Guinea pigs challenged with 15% 2-methylol phenol and re-challenged with 13.1% o-cresol showed positive skin reactions. However, the study was assessed as not reliable as test substance was only used in re-challenge and positive results in control animals occured. Therefore, this study was assessed as not reliable for hazard assessment of the target substance.

Applicant's summary and conclusion

Interpretation of results:
other: CLP/EU GHS Category 1B (H317) according to Regulation (EC) No 1272/2008
Conclusions:
The GPMT on o-cresol did not provide sufficient information to allow a definitive conclusion to be drawn. Both the Draize test and the human maximisation test on p-cresol confirmed this cresol isomer to be a non-sensitiser. Within the studies available on xylenols, 3,5-xylenol returned an equivocal result. Whilst the author of this study concluded that the test material, 3,5-xylenol did not exhibit any skin sensitising potential, due to similar skin reactions being elicited by the solvent and the test preparation, the outcome of the study could not be concluded with confidence. The study conducted on 2,4-xylenol returned a positve result, furthermore, no reactivity with the solvent was observed.
Based on all available information (weight-of-evidence), following an analogue read-across approach and in the absence of data on skin sensitisation of Tar acids, Xylenol fraction (CAS 84989-06-0), Tar acids, Xylenol fraction (CAS 84989-06-0) is classified for Skin Sens. 1B (H317) as a worst case.