Sodium N-(2-carboxyethyl)-N-dodecyl-β-alaninate

Endpoint summary

Description of key information

Based on the available information from the Draize test, the test item is not considered to be sensitizing to the skin.

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:

1963

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

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

Principles of method if other than guideline:

The testing method was based on the Draize test as described in Draize et al. (1944), J Pharm and Exp Ther 82. Each of ten guinea pigs received a series of 10 injections of 0.1% test item solution, every other day, in a depilated skin region below the midline of the back. The first injected volume was 0.05 mL, the following injected volumes were 0.1 mL each. After 2 weeks following the last induction injection, challenge was conducted by injection of 0.05 mL of the test solution in the skin of the flank. The injection site was examined for skin reaction after a period of 24 hours following challenge.

GLP compliance:

no

Type of study:

Draize test

Justification for non-LLNA method:

Currently no LLNA study is available for assessment. The Draize test has been carried out as an animal test to predict human sensitisation for over a decade and is recommended by international test guidelines.

Species:

guinea pig

Strain:

not specified

Sex:

male

Details on test animals and environmental conditions:

TEST ANIMALS
- Source: not specified
- Weight at study initiation: 350 - 450 g
- No further details given

Route:

intradermal

Vehicle:

physiological saline

Concentration / amount:

0.1%

Day(s)/duration:

daily injections for a period of 20 days

Route:

intradermal

Vehicle:

physiological saline

Concentration / amount:

0.15%

Day(s)/duration:

2 weeks after last induction injection / single injection

No. of animals per dose:

10

Details on study design:

A. INDUCTION EXPOSURE
- No. of exposures: 10
- Exposure period: 20 days
- Site: depilated skin region below the midline of the back
- Frequency of applications: injection was done every other day
- Concentrations: 0.1% test item solution
- Injected volume: 0.1 mL, except for the first injection (0.05 mL)
- Reading: skin readings were made at the injection sites, 24 hours after each injection had been done; the skin was examined for diameter, heigh and colour.

B. CHALLENGE EXPOSURE
- No. of exposures: one
- Challenge: done after 2 weeks following the last induction injection
- Site: skin of the flank.
- Concentrations: 0.1% test item solution
- Injected volume: 0.05 mL
- Evaluation (hr after challenge): 24 hours

READING
The application site was examined for diameter, heigh and colour. The readings were compared with those made at the sites of the first injection series (induction). If the reactions after challenge were appreciably more pronounced than those observed during induction, the test item was defined as a sensitizer. The degree of sensitization was considered to be, in part, proportional to the observed increase in skin reaction.

Key result

Reading:

1st reading

Hours after challenge:

24

Group:

test chemical

Dose level:

0.1%

No. with + reactions:

0

Total no. in group:

10

Clinical observations:

Skin reaction at induction was characterized by a mean diameter of 3.6 mm, a mean height of < 1 mm, and a pink coloration (indicates slight erythema). Reaction after challenge had a mean diameter of 3.5 mm, a mean height of < 1mm, and a pink coloration.

Interpretation of results:

GHS criteria not met

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not sensitising)

Additional information:

Non-LLNA in-vivo test:

The test item (10% in water) was tested at a concentration of 0.1% for sensitisation according to the method of Draize (Draize et al., 1944) using 10 guinea pigs. Induction consisted of a series of 10 injections of 0.1 mL of test solution, except for the first injection done with 0.05 mL. The injections were done every other day over a period of 20 days. After 2 weeks following the last induction injection, challenge was done by single injection of 0.05 mL of the 0.1% test solution; skin reading was done after 24 hours. Since no obvious differences were noticed when comparing the skin reaction at induction and that after challenge, the test substance was not found to be a skin sensitizer under the test conditions used (IBT, 1963).

Additional information based on exposure related observations in humans:

In a human repeated insult patch test (HRIPT) a foaming face wash formulation containing 2.2% sodium lauriminodipropionate (concentration is expressed here as active; the ingredient was added at 7.34% and consisted of 30% sodium lauriminodipropionate). The formulation was tested as a 2.0% (w/v) solution in distilled water. 0.2 mL of the test article was applied to a 2 x 2 cm patch. One hundred and four subjects completed the study. Under the conditions employed in the study, there was no evidence of sensitization. (TKL, 1991).

The last result was also confirmed by another human sensitisation test conducted with a shampoo formulation containing 3.5% sodium launminodipropionate (concentration is expressed here as active: the ingredient was added at 11.67% and consisted of 30% sodium launminodipropionate). The formulation was tested as a 2.5% solution in distilled water. 0.5 mL of the test article was applied to a webril disc. One hundred and sixteen subjects completed the study. Under the conditions of this study, there was no evidence of delayed contact hypersensitivity to the shampoo formulation containing 3.5% sodium lauriminodipropionate. One subject had mild to moderate erythematous reactions during induction and a response at challenge at the original site at both 48 and 96 hour scoring that warranted further follow-up. This subject was rechallenged with application to both the original arm and the alternate arm with the original test formulation, with a similar shampoo formulation also containing 3.5% sodium lauriminodipropionate (both tested as 2.5% solutions in distilled water), and with the fragrance used (test material G3543.01) (tested at 0.4% in mineral oil). The only response at rechallenge was mild erythema to one subject at the 48 hour scoring on the original arm. This response had returned to normal (grade 0) by the 96 hour scoring. Mild erythematous reactions were reported in a number of other panelists during the induction phase as well as at challenge, and these, as well as the response in panelist 54, were judged to be irritant responses and consistent with the nature of the test material (i.e., a surfactant containing shampoo) (North Cliff Consultants Inc. 1992).

 

Assessment sensitisation:

There was no evidence for skin sensitisation observed in animal test up to 10% active ingredient or in human patch test up to 3.5% active ingredient. In summary based on the result the substance is considered to be not sensitising to skin.

Respiratory sensitisation

Endpoint conclusion

Endpoint conclusion:

no study available

Justification for classification or non-classification

Based on the available information, classification for skin sensitisation is not warranted in accordance with EU Classification, Labelling and Packaging of Substances and Mixtures (CLP) Regulation No. 1272/2008.