N6-(1-oxododecyl)-L-lysine

Endpoint summary

Description of key information

In a study with guinea pigs the test item was applied to the site of challenge at flank to induce delayed type skin reaction, but redness was not observed. In 0.1% DNCB sensitized guinea pigs used as a positive control, erythema were evaluated as “grade 2” in all animals. When a 50% test item solution and 0.1% DNCB were applied to the FCA sensitized guinea pigs, no redness was observed in the flank. Therefore, the test item was not judged to be a source antigen eliciting contact skin allergic reaction.

Key value for chemical safety assessment

Skin sensitisation

Link to relevant study records

Reference

Endpoint:

skin sensitisation: in vivo (non-LLNA)

Type of information:

experimental study

Adequacy of study:

key study

Study period:

1984

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

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

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 406 (Skin Sensitisation)

Version / remarks:

Modified maximization test

GLP compliance:

not specified

Type of study:

guinea pig maximisation test

Justification for non-LLNA method:

Study was performed in 1984

Specific details on test material used for the study:

not further specified

Species:

guinea pig

Strain:

Hartley

Sex:

female

Details on test animals and environmental conditions:

Female Hartley strain guinea pigs (weighing about 250 g on arrival, at age 3 - 4 weeks) were purchased from Shizuoka Agricultural Cooperative Association for Laboratory Animals and housed in wire cages with automatic water supply and automatic cleaning in an animal facility adjusted to temperature 21 - 25°C and humidity 45 - 70%. Animals were fed Oriental Yeast Co. RC-4 produced within recent 3 months, and allowed to drink tap water at libitum.

Route:

intradermal

Vehicle:

physiological saline

Concentration / amount:

1.25 % (w/w)

Route:

epicutaneous, occlusive

Vehicle:

olive oil

Concentration / amount:

50 % (w/w)

Route:

epicutaneous, occlusive

Vehicle:

olive oil

Concentration / amount:

50 % (w/w)

No. of animals per dose:

10-15

Details on study design:

Types of sensitized groups
The test item was used to sensitize 15 animals, DNCB to sensitize 10 animals, and FCA to sensitize 10 animals that served as the control (body weight at the time of sensitization was 274 - 450 g). Each cage was labelled with study number, the type of sensitizing antigen and the number of animals/cage, while guinea pigs were individually identified by use of picric acid and oily ink.

Methods of sensitization
1.) Sensitization by intradermal injection
Each antigen for immunization emulsified with FCA was intradermally injected to 4 corners of the shaved scapular region (3×4 cm) of the guinea pig skin (0.1 mL/site), to sensitize the guinea pig.
2.) Sensitization by spreading
Immediately after intradermal injection, the stratum corneum at the site of injection was nicked with a 23 G needle to create a #-shaped injury, then a piece of vinyl filter paper (3×4 cm) spread with 0.4 mL each of antigen for immunization was applied to the shaved region, fixed with an adhesive tape (Johnson & Johnson), and left there for 24 hours under occlusion to sensitize the animal. After removal of vinyl filter paper, occlusive dressing for 24 hours was repeated twice. On day 8 after the first sensitization, the guinea pig scapular region was again shaved, and spread with about 200 mg/animal of 10% SDS petrolatum. At 24 hours after spreading, a piece of vinyl filter paper spread with 0.2 mL each of antigen for immunization (3×4 cm) was applied to the same site, fixed with an adhesive tape, and left there under occlusion for 48 hours. 50% Nε-lauroyl-L-lysine was used in Nε-lauroyl-L-lysine sensitized group, 0.1% DNCB solution in DNCB sensitized group, and olive oil in FCA sensitized group, in spreading.
3.) Induction of delayed type skin reaction
On day 22 after the first sensitization, a piece of vinyl filter paper (2×3 cm) spread with 2 mL of antigen for challenge (50% Nε-lauroyl-L-lysine or 0.1% DNCB solution) was applied to the shaved and actively sensitized flank of the guinea pig, fixed with adhesive tape, and left there for 24 hours under occlusion to induce delayed type skin reaction. Time for the removal of tape was at 24 hours after challenge, and the flank was observed at 24 hours and 48 hours after challenge, twice in total. The findings in this observation were classified to the following 4 gradings:
0 = No macroscopic change
1 = Slight or minimal erythema
2 = Moderate erythema
3 = Severe erythema and oedema
As control for Nε-lauroyl-L-lysine sensitized and DNCB sensitized groups, the same amount of antigen for challenge as used in the challenge was applied, namely, 50% Nε-lauroyl-L-lysine and 0.1% DNCB were applied respectively to the left and right flank of the FCA sensitized guinea pig, and the flank was observed for the presence or absence of the symptoms elicited by primary stimulation with the samples such as redness and oedema.

Challenge controls:

see above

Positive control substance(s):

yes

Remarks:

DNCB

Positive control results:

DNCB caused an erythema "grade 2" in all animals

Key result

Reading:

1st reading

Hours after challenge:

24

Group:

test chemical

No. with + reactions:

0

Total no. in group:

15

Remarks on result:

no indication of skin sensitisation

Key result

Reading:

2nd reading

Hours after challenge:

48

Group:

test chemical

No. with + reactions:

0

Total no. in group:

15

Remarks on result:

no indication of skin sensitisation

Interpretation of results:

GHS criteria not met

Remarks:

Migrated information

Conclusions:

Test item was not allergic to the skin.

Executive summary:

In a study with guinea pigs the test item was applied to the site of challenge at flank to induce delayed type skin reaction, but redness was not observed. In 0.1% DNCB sensitized guinea pigs used as a positive control, erythema were evaluated as “grade 2” in all animals. When a 50% test item solution and 0.1% DNCB were applied to the FCA sensitized guinea pigs, no redness was observed in the flank.

Therefore, the test item was not judged to be a source antigen eliciting contact skin allergic reaction.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not sensitising)

Respiratory sensitisation

Endpoint conclusion

Endpoint conclusion:

no study available

Justification for classification or non-classification

In a study with guinea pigs the test item gave no indication for a significant skin sensitizing potential. Therefore, there is no need for classification and labelling of the test item according to CLP Regulation 1272/2008/EG.