Sodium 2-stearoyllactate

Skin sensitisation

Administrative data

Endpoint:

skin sensitisation: in vitro

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:

publication

Title:

Skin toxicity of surfactants: Structure/toxicity relationships

Author:

Lemery E., Briancon S., Chevalier Y., Bordes C., Oddos T., Gohier A., Bolzinger M.-A.

Year:

2015

Bibliographic source:

Colloids and Surfaces A: Physicochem. Eng. Aspects 469 (2015) 166–179

Materials and methods

Principles of method if other than guideline:

A cytotoxicity test was conducted on reconstructed human epidermis (RhE) tissues. The test substance was topically applied to the RhE tissues and the tissues were incubated at 37 °C, in the presence of 5% CO2 and 95% humidity, for 72 h. Following exposure to the test substance, the RhE growth medium was screened for the primary inflammation marker Interleukin-1α (IL-1α) and the delayed inflammation marker Interleukin-8 (IL-8).

GLP compliance:

no

Remarks:

Investigation reported in a scientific publication

Type of study:

other: detection of the inflammation markers Interleukin IL-1α and IL-8

Test material

Test material information

Constituent 1

Reference substance name:

Sodium 2-stearoyllactate

EC Number:

246-929-7

EC Name:

Sodium 2-stearoyllactate

Cas Number:

25383-99-7

Molecular formula:

This reference substance is a UVCB of the NCS type. It is a complex mixture of compounds and therefore molecular formula, molecular weight, SMILES, InChI and structural formula cannot be given.

IUPAC Name:

sodium 2-hydroxy-2-methyl-3-oxoicosanoate

In vitro test system

Details on the study design:

A cytotoxicity test was conducted on reconstructed human epidermis (RhE) tissues. Upon delivery, RhE devices were transferred into 3 mL of RhE aqueous growth medium, free from antibiotics and hydrocortisone, and treated immediately.Three reconstructed human epidermis (RhE) tissues were treated with 10 µL of an emulsion containing the test substance at a concentration of 3%. The test substance emulsion was topically applied at the center of the RhE surface. Four untreated RhE tissues were used as controls. Each sample (test substance and control) was placed in 3 mL of aqueous growth medium and incubated at 37 °C, in the presence of 5% CO2 and 95% humidity, for 72 h.

After the incubation period, the RhE growth medium was screened for the primary inflammation marker Interleukin-1α (IL-1α) and the delayed inflammation marker Interleukin-8 (IL-8). The collected RhE growth medium was labeled using the Fluorokine MAP Human Base Kit A and analysed by flow cytometry using the Bioplex-200 instrument (Bio-Rad, Marnes-la-Coquette, France), a device relying on a Luminex Multi-Analyte Profiling technology.

Substances are considered to induce skin sensitisation when the extracellular IL-8 > 1L-1α, and irritants when extracellular IL-8 < IL-1α.

Results and discussion

In vitro / in chemico

Results

Results 1

Run / experiment:

other: 72 h

Parameter:

other: Release of Interleukin-1a (IL-1α)

Value:

0.582 %

Vehicle controls validity:

not applicable

Negative controls validity:

not applicable

Positive controls validity:

not applicable

Results 2

Run / experiment:

other: 72 h

Parameter:

other: Release of Interleukin-8 (IL-8)

Value:

3.407 %

Vehicle controls validity:

not applicable

Negative controls validity:

not applicable

Positive controls validity:

not applicable

Other effects / acceptance of results:

Sodium stearoyl lactylate caused a significant release of IL-8 and no significant IL-1α release. The IL-8/IL-1α ratio was 5.85 (i.e. > 1). The value for release of IL-8 (3.407) was above the threshold of 3, whereas the value for the release of IL-1α (0.582) was not.

Substances applied to the skin can be considered allergens when the extracellular IL-8 > 1L-1α, and as irritants when extracellular IL-8 < IL-1α. Sodium stearoyl lactylate was predicted to be an allergen.

Applicant's summary and conclusion

Interpretation of results:

other: Sodium stearoyl lactylate was predicted to be an allergen.