Sebacic acid

Skin sensitisation

Administrative data

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:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1979

Report date:

1979

Materials and methods

Principles of method if other than guideline:

Skin sensitisation in guinea pigs, intradermal injection of test substance for induction (seven doses) and challenge.

GLP compliance:

no

Remarks:

pre-GLP

Type of study:

intracutaneous test

Justification for non-LLNA method:

In accordance with Annex VII of EC legislation 1907/2006 in-vivo testing studies apart from murine local lymph node assay (LLNA) meet the regulatory requirements if they were carried out or initiated before 11 October 2016. The described experimental test was performed by an intradermal application during induction and challenge. This reported study is much more sensitising than the epidermal application according to OECD guideline 406 (GPMT method or Buehler test method) and meet the requirements set out in Article 13(3), first subparagraph, and Article 13(4).

Test material

Test material information

Constituent 1

Reference substance name:

Sebacic acid

EC Number:

203-845-5

EC Name:

Sebacic acid

Cas Number:

111-20-6

Molecular formula:

C10H18O4

IUPAC Name:

sebacic acid

In vivo test system

Test animals

Species:

guinea pig

Strain:

Hartley

Sex:

male

Details on test animals and environmental conditions:

TEST ANIMALS
- Source: Sweetwater Farms

Study design: in vivo (non-LLNA)

Induction

Route:

intradermal

Vehicle:

peanut oil

Concentration / amount:

0.1 %

Day(s)/duration:

7 days, each at an interval of 48 h

Challenge

Route:

intradermal

Vehicle:

peanut oil

Concentration / amount:

0.1 %

Day(s)/duration:

one injection

No. of animals per dose:

20

Details on study design:

Twenty male albino guinea pigs were used to test the sensitizing potential of the materials. The sensitization test was started on a Monday when the guinea pigs were weighed and closely clipped on the scapular areas. The material (0.05 ml of a 0.1% dilution in peanut oil) was injected intradermally into the upper right scapular area of each pig. A similar injection of peanut oil alone into the upper left scapular area served as a control site. Readings were made 24 and 48 hours later. Doses of 0.1 ml of the same dilutions (freshly prepared) were injected into the clipped dorsal lumbo-sacral areas of the guinea pigs on the following Wednesday, Friday, Monday, etc., until seven doses were administered. Care was taken to insure that the repeated doses were not injected into the same site. The guinea pigs were rested for three weeks (incubation period), weighed and given a challenge dose of 0.05 ml of the 0.1% dilution of the test material into the lower right scapular area. A control injection of the vehicle alone was also administered into the lower left scapular area at this time. The reactions were read after 24 and 48 hours.
The grading system is designed so that the intensity of the skin reaction is represented by a proportionate numerical value and also that any reaction elicited by the vehicle (control substance) is subtracted from the reaction elicited by the test material and vehicle combined. The product of the width and length of the wheal (in mm) is multiplied by the following reaction scores to determine a final grade:
0 = needle puncture ("np")- no wheal
1 = very faint pink ("vfp") - no value for this reaction
2 = faint pink ("fp")
3 = pink P
4 = red ("r")
5 = bright red ("R")
6 = edema - <1 mm in height ( "e")
7 = edema - >1 mm in height ("E")
*8 = necrosis - <1 sq. mm ("n")
*9 = necrosis - >1 sq. mm ("N")
*The product of the width and length of the necrotic area multiplied by 8 or 9 is added to the numerical value of the foregoing reactions that are present and calculated in the same manner.
As a characterization of the sensitizing response which may be expected from exposure to the test material, the final grade was compared with the following categories (Final Grade --> Sensitizing Response): 0-25 --> None; 26-99 --> Mild; 100-200 --> Moderate; >200 --> Severe.
The sensitizing potential of the test material is estimated from the number of animals giving a response with a final grade of at least 25. The scale for this estimation is shown below (Number Sensitized (N=20) --> Sensitizing Potential): 1-3 --> Slight; 4-10 --> Moderate; 11-20 --> Severe.

Results and discussion

In vivo (non-LLNA)

Results

Reading:

other: overall result

Group:

test chemical

Dose level:

0.05 ml of a 0.1% dilution in peanut oil

No. with + reactions:

3

Total no. in group:

20

Applicant's summary and conclusion

Interpretation of results:

GHS criteria not met

Conclusions:

The test substance caused a mild sensitization response (final grades per animal: 26 -99) and was categorized as a substance with "slight" sensitization potential. According to the applied scoring system, this refers to 1 - 3 animals out of 20 with mild, but positive reactions (final grade per animal >= 25).