Tridecanedioic acid

Skin sensitisation

Administrative data

Endpoint:

skin sensitisation: in vivo (non-LLNA)

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2012-08-21 to 2012-10-12

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2013

Report date:

2013

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 406 (Skin Sensitisation)

Version / remarks:

(1992)

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method B.6 (Skin Sensitisation)

Version / remarks:

(2008)

Deviations:

no

Test guideline 3

Qualifier:

according to guideline

Guideline:

EPA OPPTS 870.2600 (Skin Sensitisation)

Version / remarks:

(1998)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Type of study:

guinea pig maximisation test

Test material

Test material information

Constituent 1

Reference substance name:

Tridecanedioic acid

EC Number:

208-011-4

EC Name:

Tridecanedioic acid

Cas Number:

505-52-2

Molecular formula:

C13H24O4

IUPAC Name:

tridecanedioic acid

Constituent 2

Reference substance name:

Brassylic acid

IUPAC Name:

Brassylic acid

Test material form:

solid: particulate/powder

Remarks:

migrated information: powder

Details on test material:

- Name of test material (as cited in study report): Brassylic acid/Tridecanedioic acid
- Physical state: White powder
- Analytical purity: 99.42 %
- Lot/batch No.:3311050098 of 22 August 2011
- Expiration date of the lot/batch: 27 Jun 2013
- Storage condition of test material:At room temperature

In vivo test system

Test animals

Species:

guinea pig

Strain:

Dunkin-Hartley

Sex:

male

Details on test animals and environmental conditions:

TEST ANIMALS
- Source: Charles River Laboratories, Research Models and Services, Germany GmbH, Sandhofer Weg 7, 97633 Sulzfeld, Germany
- Age at start of administration: 31 days
- Weight at start of administration: 258 – 316 g; Positive control group: 319 – 441 g
- Housing: The animals were kept in pairs in MAKROLON cages (MZK 80/25). Granulated textured wood was used as bedding material for the cages.
- Diet: Commercial diet, ssniff® R/M-H V1534 (Certificates of analysis provided) ad libitum
- Water: tap water ad libitum
- Acclimation period: At least 5 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C):22°C ± 3°C
- Humidity (%): 55% ± 15%
- Air changes (per hr): 12 to 18-fold air change per hour
- Photoperiod (hrs dark / hrs light): 12 hrs dark/12 hrs light (about 150 lux at approx. 1.50 m room height)

IN-LIFE DATES: From: August 21, 2012 To:October 12, 2012

Study design: in vivo (non-LLNA)

Induction

Induction 1

Route:

intradermal and epicutaneous

Vehicle:

other: Sesame oil

Induction 2

Concentration / amount:

The concentrations of test substance in the main study (as determined in the preliminary test) were selected as follows:

Intradermal Induction: 10% suspension of Brassylic acid in sesame oil
Topical Induction: 50% suspension of Brassylic acid in sesame oil
Topical Challenge: 25% suspension of Brassylic acid in sesame oil

Challenge

Challenge 1

Route:

epicutaneous, occlusive

Vehicle:

other: Sesame oil

Challenge 2

Concentration / amount:

The concentrations of test substance in the main study (as determined in the preliminary test) were selected as follows:

Intradermal Induction: 10% suspension of Brassylic acid in sesame oil
Topical Induction: 50% suspension of Brassylic acid in sesame oil
Topical Challenge: 25% suspension of Brassylic acid in sesame oil

No. of animals per dose:

Test group: 20 animals
Control group: 10 animals

Details on study design:

The concentrations of the test substance to be used at each stage of the main study were determined in a preliminary study. Eight animals were used for the preliminary test: 6 animals for the topical administration and 2 animals for the intracutaneous administration. The shoulder and the flank region of the animals were shaved or shaved and depilated (approx. 5 x 5 cm2). The allocation of different test sites of the animals was alternated in order to minimize site-to-site variations in response.

For intracutaneous exposure, 0.1 mL of the prepared test substance was administered intracutaneously (shoulder region). Three concentrations (0.01, 0.1 and 0.5%) of the test substance were injected intradermally into one animal and 3 further concentrations (1, 5, 10%) into a second animal.
For topical exposure, the test area of 3 animals each was shaved or shaved and depilated. 2 mL of the test item preparation was spread over a filter paper (2 cm x 4 cm) and applied to the test area and held in contact by an occlusive dressing. The concentrations of the test substance were 1, 5, 10 ,25 and 50% .

Two concentrations each were applied to the shaved or shaved and depilated flanks of 3 animals each. The occlusive dressing and the filter paper containing the test substance were removed after 24 or 48 hours and the application sites were assessed immediately, 24 and 48 hours (depilated) or immediately and 24 hours (non-depilated) after removal of the filter paper for erythema and oedema using the grading system listed in Annex I - Preliminary study results.

A. INDUCTION EXPOSURE

(Stage 1)

- No. of exposures: On Day 0, three pairs of intradermal injections of 0.1 mL were given in the shoulder region which was cleared of hair so that one of each pair lay on each side of midline.

- Exposure period: The skin reaction results of the first induction exposure were evaluated at 24 and
48 hours after beginning of exposure according to the MAGNUSSON/KLIGMAN grading scale in Table A1.

- Test groups: 20 animals
- Control group: 10 animals

- Site: the shoulder region. Injections (1) and (2) were given close to each other and nearest the head, while (3) was given towards the caudal part of the test area.

- Concentrations:
Test animals:
a) Freund's complete adjuvant (diluted 1 : 1 with 0.9% NaCl)
b) 10% suspension of Brassylic acid in sesame oil
c) the test substance in a 1:1 mixture (v/v) FCA/physiological saline (final concentration: 10 % Brassylic acid).

Control animals:
a) Freund's complete adjuvant (diluted 1 : 1 with 0.9% NaCl)
b) Sesame oil
c) Sesame oil in a 1:1 mixture (v/v) FCA/physiological saline

On Day 6, fur was shaved from the application area and the exposed skin was coated with 0.5 mL sodium laurylsulfate 10% in vaseline in order to induce a local irritation (irritation was not noted at 50% test substance in preliminary study).

(Stage 2)

Seven days after the intracutaneous injection, the shoulder region of the same animals (shaved one day before) was treated topically using the patch-test technique (exposure time: 48 hours). No cleaning of the skin was necessary. The skin reaction results were observed at 48 and 72 hours after beginning of exposure according to the MAGNUSSON/KLIGMAN grading scale in Table A1.

B. CHALLENGE EXPOSURE

(Stage 3)

- No. of exposures: one

- Day(s) of challenge: on Day 21

- Exposure period: On Day 21, flanks of the same animals were shaved and depilated for a further topical application using the patch-test technique. The filter paper containing the test substance was applied to the left flank, the filter paper with the vehicle to the right flank of the animal (exposure time: 24 hours). 21 hours after the filter paper had been removed, no cleaning of the treated skin was necessary.

- Test groups: 20 animals
- Control group: 10 animals

- Site: left flank was treated with the test substance, the right flank with the vehicle

- Concentrations:

a) 25% suspension of Brassylic acid in sesame oil (test group)
b) sesame oil (control group)

- Evaluation (hr after challenge): On Days 23 and 24: (i) 21 hours after removing the filter paper the challenge area was cleaned and cleared of hair if necessary (ii) three hours later (at 48 hours from the start of challenge application) the skin reaction was observed and recorded (iii) 24 hours after this observation a second observation (72 hours) was made and recorded. The skin reactions were graded according to the MAGNUSSON/KLIGMAN grading scale in (Table A1).

OTHER:

Positive control:
The animals of the positive control group (Guinea pig / Dunkin-Hartley) were treated with a 10% (v/v) α-hexyl cinnamic aldehyde solution intracutaneously in stage 1, undiluted α-hexyl cinnamic aldehyde topically in stage 2 and a 0.01% α-hexyl cinnamic aldehyde solution in stage 3.

Other observations:
Mortality and clinical signs: daily during the observation period
Body weight: at start of study and at study termination. Body weight was analysed statistically using STUDENT's t-test (p ≤0.01).

Results and discussion

Positive control results:

The positive control group was not tested concurrently with this study but is a historical background group from a study performed during May 2012 (LPT 2013 (Table 1)) attachment.

In vivo (non-LLNA)

Results

Results 1

Reading:

1st reading

Hours after challenge:

48

Group:

test chemical

Dose level:

25%

No. with + reactions:

0

Total no. in group:

20

Remarks on result:

other: Reading: 1st reading. . Hours after challenge: 48.0. Group: test group. Dose level: 25%. No with. + reactions: 0.0. Total no. in groups: 20.0.

Results 2

Reading:

2nd reading

Hours after challenge:

72

Group:

test chemical

Dose level:

25%

No. with + reactions:

0

Total no. in group:

20

Remarks on result:

other: Reading: 2nd reading. . Hours after challenge: 72.0. Group: test group. Dose level: 25%. No with. + reactions: 0.0. Total no. in groups: 20.0.

Results 3

Reading:

1st reading

Hours after challenge:

48

Group:

negative control

Dose level:

25%

No. with + reactions:

0

Total no. in group:

10

Remarks on result:

other: Reading: 1st reading. . Hours after challenge: 48.0. Group: negative control. Dose level: 25%. No with. + reactions: 0.0. Total no. in groups: 10.0.

Results 4

Reading:

2nd reading

Hours after challenge:

72

Group:

negative control

Dose level:

25%

No. with + reactions:

0

Total no. in group:

10

Remarks on result:

other: Reading: 2nd reading. . Hours after challenge: 72.0. Group: negative control. Dose level: 25%. No with. + reactions: 0.0. Total no. in groups: 10.0.

Any other information on results incl. tables

Study report attachments:

LPT 2013 (Table 1 Skin reactions - main study)

LPT 2013 (Table 2 Bodyweights - main study)

LPT 2013 (Annex I - Preliminary study results)

Applicant's summary and conclusion

Interpretation of results:

not sensitising

Remarks:

Migrated information Criteria used for interpretation of results: EU

Conclusions:

In this test system, Brassylic acid revealed no sensitising properties in guinea pigs according to MAGNUSSON and KLIGMAN.

Executive summary:

In a dermal sensitization study with Brassylic acid, Dunkin-Hartley guinea pigs were tested using the method of Magnusson and Kligman (Maximisation test).

In the preliminary study, 6 concentrations of Brassylic acid were tested by intracutaneous injection in 2 male animals: 0.01, 0.1, 0.5, 1, 5 or 10% suspensions in sesame oil: Concentrations up to 5% did not reveal any skin reactions. The concentration of 10% revealed a discrete or patchy erythema 24 hours after administration and was considered the maximum feasible applicable concentration. Six concentrations of Brassylic acid were tested by topical application in 6 male animals: 1, 5, 10, 25 and 50% suspensions in sesame oil. For the non-depilated skin group, no skin reactions were observed. In the depilated skin group, there were no skin reactions up to 25%.At 50% a discrete or patchy erythema was observed at 24 hours after start of exposure. Based on these results, the following concentrations were chosen for the main study: 10% concentration in sesame oil for the 1st (intracutaneous) stage, a 50% concentration for the 2nd (topical) induction stage and a 25% suspension in sesame oil for the challenge.

In the main study, 20 male test animals and 10 male control animals were used. For intradermal induction exposure, discrete or patchy erythema was observed in animals treated with 10% Brassylic acid in sesame oil concentration in all animals after 24 hours. In the preliminary study (epicutaneous induction exposure), it was noted that 2 mL of a 50% suspension of Brassylic acid in sesame oil/animal was not irritating to the shaved skin, so for the main study (epicutaneous induction exposure) the skin was coated with sodium laurylsulfate on the day before in order to induce a local irritation. This treatment resulted in a discrete or patchy erythema 48 and 72 hours after start of exposure in all test group animals. For the challenge phase of the study, 2 mL of a 25% suspension of Brassylic acid in sesame oil/animal (the maximum non-irritating concentration) revealed no skin irritation in any animal. The vehicle control revealed no skin reactions. The positive control group was not tested concurrently with this study but is a historical background group from a study performed during May 2012. Dunkin-Hartley guinea pigs treated with α-hexyl cinnamic aldehyde in sesame oil exhibited a sensitising reaction in all animals in form of a discrete or patchy erythema (grade 1).

There were no mortalities or clinical signs observed during the study. There were no statistically significant changes in body weight during the study. No necropsy was performed as no animal was found dead or was sacrificed in extremis. The results indicated that Brassylic acid was not a skin sensitiser at the challenge concentrations in any test animals. No reactions were noted in the negative control group. Brassylic acid is not a dermal sensitiser in this test system.