Registration Dossier

Toxicological information

Skin sensitisation

Currently viewing:

Administrative data

Endpoint:
skin sensitisation: in vivo (non-LLNA)
Type of information:
experimental study
Adequacy of study:
weight of evidence
Study period:
2008
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
guideline study without detailed documentation
Justification for type of information:
Succinic acid may be used as an analogue for alkylsuccinic acid as this is the potentially biologically cative part of the molecule.
Dicarboxylic acids are naturally occurring metabolic products of fatty acid oxidation, and are rapidly beta-oxidised. A category approach for short-medium chain dicarboxylic acids, including malonic acid and succinic acid, has been validated and used by various bodies including the Cosmetics Ingredient Review Panel and the European Food Safety Authority.The study was carried out to provide a comparison between the LLNA and GPMT tests, rather than to investigate the properties of the test materials, nevertheless it follows standard OECD guidelines and was carried out in accordance with GLP.

Data source

Reference
Reference Type:
publication
Title:
Unnamed
Year:
2008

Materials and methods

Test guideline
Qualifier:
according to guideline
Guideline:
OECD Guideline 406 (Skin Sensitisation)
GLP compliance:
yes
Type of study:
guinea pig maximisation test
Justification for non-LLNA method:
The tes was carried out as part of a study to compare the suitability of the LLNA and GPMT methods to detect sensitisation potential.

Test material

Constituent 1
Chemical structure
Reference substance name:
Succinic acid
EC Number:
203-740-4
EC Name:
Succinic acid
Cas Number:
110-15-6
Molecular formula:
C4H6O4
IUPAC Name:
succinic acid
Specific details on test material used for the study:
Succinic acid (Aldrich No. 398055), purity 99%, was obtained from Sigma-Aldrich (Munich, Germany)

In vivo test system

Test animals

Species:
guinea pig
Strain:
other: SPF-Hsd Poc: DH guinea pig
Sex:
female
Details on test animals and environmental conditions:
Non-pregnant, nulliparous female SPF-Hsd Poc: DH guinea pigs (300–500 g at the commencement of the study) were purchased from Harlan Winkelmann(Borchen, Germany). The guinea pigs were housed in groups in Terluran cages on Altromin saw fiber bedding or Lignocel bedding. The animals were barrier-maintained (semi-barrier) in an air conditioned room (temperature 22 ± 3 C, relative humidity 55 ± 10%) with a 12-h light/dark cycle and air change rate of at least 10x/h. The acclimatization period was at least five days. Food (Altromin 3122 maintenance diet for guinea pigs or ssniff Ms-H, 4mm V2233-000 complete diet for guinea pigs, rich in crude fiber, totally-pathogen-free) and tap water were provided ad libitum.

Study design: in vivo (non-LLNA)

Induction
Route:
intradermal and epicutaneous
Vehicle:
other: Isotonic saline (NaCl 0.9%)
Concentration / amount:
0.5% intradermal25% topical
Day(s)/duration:
Intradermal injection (day 0), topical application (day 7)
Adequacy of induction:
non-irritant substance, but skin pre-treated with 10% SDS
Challengeopen allclose all
No.:
#1
Route:
epicutaneous, occlusive
Vehicle:
unchanged (no vehicle)
Concentration / amount:
0.5 g test substance
Day(s)/duration:
Day 20
Adequacy of challenge:
not specified
No.:
#2
Route:
epicutaneous, occlusive
Vehicle:
unchanged (no vehicle)
Concentration / amount:
0.5 g test substance
Day(s)/duration:
Day 28
Adequacy of challenge:
not specified
No. of animals per dose:
10 test animals and 5 controls
Details on study design:
, a gauze patch with 0.5 g of thetest compound was applied to the clipped skin and held under occlusionfor 48 h. Control animals received the vehicle without test compound.After a resting period, topical challenge treatments were performed on day20 and on day 28 by applying 0.5 g test compound for 24 h under occlusiononto the clipped skin of both test and control animals.Approximately 21 h after removal of the challenge patch, the skin areawas cleaned and cleared of hair. About 24 and 48 h after removal of thepatch, the skin reaction was observed and recorded. In addition to the requirements of the OECD guideline,an additional reading of skin reactions was performed at 72 h after patchremoval.RANGE FINDING TESTS: A range finding for the test concentrations was performed in a preliminary experiment assessing the irritant effects of the test compounds after intradermal and topical application. MAIN STUDY A. INDUCTION EXPOSURE - No. of exposures: 2 - Test groups: The animals received two induction treatments, an intradermal injection (day 0) and a topical application (day 7). The intradermalinduction comprised three pairs of injections of 0.1 ml each of the test compound in vehicle, the test compound in a 1:1 (v/v) mixture of FCA/physiological saline and a 1:1 (v/v) mixture of FCA/physiological saline without test compound. Approximately 24 h before the topical induction treatment (day 6) the test animals received a topical application of 0.5 ml of 10% sodium lauryl sulphate in Vaseline in order to create a mild local skin irritation. - Control group: The control animals received applications without test substance. B. CHALLENGE EXPOSURE - No. of exposures: 2 - Day(s) of challenge: Day 20 and 28 - Test groups: topical challenge treatments were performed by applying 0.5 g test compound for 24 h under occlusion onto the clipped skin of both test and control animals. - Evaluation (hr after challenge): 24, 48, 72 h

Results and discussion

Positive control results:
Positive control not needed as a range of substances were being tested, some of which gave clear positive results.

In vivo (non-LLNA)

Resultsopen allclose all
Reading:
1st reading
Hours after challenge:
24
Group:
test chemical
Dose level:
10%
No. with + reactions:
1
Total no. in group:
10
Reading:
1st reading
Hours after challenge:
24
Group:
negative control
Dose level:
10%
No. with + reactions:
1
Total no. in group:
5
Reading:
2nd reading
Hours after challenge:
48
Group:
test chemical
Dose level:
10%
No. with + reactions:
0
Total no. in group:
10
Reading:
2nd reading
Hours after challenge:
48
Group:
negative control
Dose level:
10%
No. with + reactions:
0
Total no. in group:
5
Reading:
other: 3rd reading
Hours after challenge:
72
Group:
test chemical
Dose level:
10%
No. with + reactions:
1
Total no. in group:
10
Reading:
other: 3rd reading
Hours after challenge:
72
Group:
negative control
Dose level:
10%
No. with + reactions:
0
Total no. in group:
5
Reading:
rechallenge
Hours after challenge:
24
Group:
test chemical
Dose level:
10%
No. with + reactions:
0
Total no. in group:
10
Reading:
rechallenge
Hours after challenge:
24
Group:
negative control
Dose level:
10%
No. with + reactions:
0
Total no. in group:
5
Reading:
rechallenge
Hours after challenge:
48
Group:
test chemical
Dose level:
10%
No. with + reactions:
0
Total no. in group:
10
Reading:
rechallenge
Hours after challenge:
48
Group:
negative control
Dose level:
10%
No. with + reactions:
0
Total no. in group:
5
Reading:
rechallenge
Hours after challenge:
72
Group:
test chemical
Dose level:
10%
No. with + reactions:
0
Total no. in group:
10
Reading:
rechallenge
Hours after challenge:
72
Group:
negative control
Dose level:
10%
No. with + reactions:
0
Total no. in group:
5

Any other information on results incl. tables

Results of the guinea pig maximization tests

Test substance

Number of test animals showing skin reaction grade P 1 (reactions in control group)

Number of animals showing reproducible skin reactions in both challenges

 

First challenge

Re-challenge

 

Reading time (h)

Reading time (h)

 

24

48

72

24

48

72

Succinic acid

1/10 (1/5)

0/10 (0/5)

1/10 (0/5)

0/10 (0/5)

0/10 (0/5)

0/10 (0/5)

0

 

Succinic acid caused skin reactions in two animals of the treatment group, one showing a reaction only at 24 h after patch removal and another only at 72 h. Moreover, one animal of the control group showed a skin reaction of the same grade and time course, i.e., a grade 1 reaction at 24 h, but not at 48 and 72 h. Neither of the two animals of the treatment group displayed a skin reaction upon re-challenge, supporting the conclusion that the reactions in these animals (as that of the control group) were non-specific, i.e., not caused by a specific immune reaction.

Applicant's summary and conclusion

Interpretation of results:
GHS criteria not met
Conclusions:
Test results in the guinea pig maximisation test for succinic acid were negative and the substance is not classified as a sensitiser.
Executive summary:

The skin sensitization potential of eight unsaturated and one saturated lipid (bio)chemicals was tested in both the LLNA and the GPMT to address the hypothesis that chemicals with unsaturated carbon–carbon double bonds may result in a higher number of unspecific (false positive) results in the LLNA compared to the GPMT. In this test series, succinic acid gave clearly negative results and was not considered sensitising.