Magnesium neodecanoate

Endpoint summary

Description of key information

No skin sensitisation study with magnesium neodecanoate is available, thus the skin sensitisation potential will be addressed with existing data on the individual moieties magnesium and neodecanoic acid.

Magnesium neodecanoate is not expected to show signs of dermal sensitisation, since the two moieties magnesium and neodecanoic acid have not shown any skin sensitisation potential in experimental testing.

Key value for chemical safety assessment

Skin sensitisation

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not sensitising)

Additional information:

No skin sensitisation study with magnesium neodecanoate is available, thus the skin sensitisation potential will be addressed with existing data on the individual moieties magnesium and neodecanoic acid.

Magnesium

Evaluation of the sensitization potential of a substance was usually carried out in animal models. Nowadays, there is much interest in reducing and ultimately replacing current animal tests. The human cell line activation test (h-CLAT) and the ARE-Nrf2 luciferase test method were recently adopted as alternative methods for skin sensitization. Both test systems are based on human cell lines, such as the human monocytic leukaemia cells THP-1 and the KeratinoSens™ cells which are cultured either in RMPI-1640 medium or DMEM (OECD guideline No. 422D and 422E). Both media are supplemented with magnesium salts at concentrations ranging from 0.4 to 0.81 mM. These methods were validated and accepted under these conditions and demonstrate that in vitro cell culture systems are dependent on magnesium containing media.

Other commercial available and daily used cosmetic products (body cream or lotion) contain magnesium sulphate and magnesium stearate. The Cosmetic Ingredient Review (CIR) Expert Panel reviewed the safety of magnesium sulphate, which functions as a bulking agent in cosmetic products and is being used at concentrations up to 11 % and 25 % in leave-on and rinse-off products, respectively. The CIR Expert Panel noted that the history of safe medical use of magnesium sulphate indicates no significant toxicity concerns relating to systemic exposure to this ingredient. “The skin sensitization potential of anhydrous magnesium sulphate (in propylene glycol) was evaluated using the mouse local lymph node assay, according OECD Guideline 429. Three groups of 5 mice were used, and the dorsal surface of both ears was epidermally treated with the test substance (10 %, 25 %, and 50 %) at a dose volume of 25 μL/ear. A vehicle control group was also included in the study. The animals were then injected i.v. with3H-methyl thymidine, killed, and the draining auricular lymph node of each ear was excised. Lymph nodes were pooled for each animal, and cell suspensions prepared. The stimulation index (SI) was calculated for each group. The SI is defined as the ratio of the DPM/group compared to the DPM/vehicle control group. Because there was no indication that the test substance elicited an SI of ≥ 3 when tested up to a concentration of 50 %, anhydrous magnesium sulphate was considered a non-sensitizer” (Cosmetic Ingredient Review Expert Panel, 2014).

Magnesium stearate is widely used in cosmetic products because of its adhesive and waterproofing properties such as a dry binder in face powders. It was reported to be used in 167 preparations in 1976, with the highest concentration occurring in face powder up to 25 %. In 2001 the FDA summarized that magnesium stearate was used in 96 preparations with a concentration ranging from 0.02- 8 %. Magnesium stearate is insoluble in water and is also used as food supplement or for drug manufacturing. A safety assessment of magnesium stearate was published in 1982 with the conclusion that this substance “is safe as cosmetic ingredient in the present practices of use and concentration” (Elder 1982).

For reference list please refer to endpoint summary of the moieties.

Neodecanoic acid

Neodecanoic acid has been examined for skin sensitization potential in the guinea pig maximization test of Magnusson and Kligman. Groups of ten male and ten female guinea pigs were used for the test and a further five males and five females as controls. Induction was accomplished in two stages. 1) Intradermal injection: Two rows of three injections were made, one on each side of the midline in the shorn skin of the shoulder region. 2) Topical application: One week after the intradermal injections, the same area was clipped free from hair. A 4x4 cm patch of filter paper was soaked in a solution of the test material and placed over the injection sites and covered with an occlusive dressing. The dressing was left in place for 48 hours. The challenge procedure was carried out two weeks after topical induction. Challenge was accomplished by topical application of the test material to the flank of animals via an occluded patch. The challenge lasted 24 hours. Immediately after the challenge, and then again at 24 and 48 hours later, each animal was examined for signs of skin sensitization. At no point was there any evidence of skin sensitization produced by neodecanoic acid.   

Magnesium neodecanoate

Magnesium neodecanoate is not expected to have a skin sensitising activity, since the two moieties magnesium and neodecanoic acid have not shown any skin sensitisation potential in experimental testing. Further testing is not required. For further information on the toxicity of the individual moieties, please refer to the relevant sections in the IUCLID and CSR.

Respiratory sensitisation

Endpoint conclusion

Endpoint conclusion:

no study available

Justification for classification or non-classification

As the two moieties of magnesium neodecanoate are not sensitising, magnesium neodecanoate in all probability has also no sensitising activity. According to the criteria of REGULATION (EC) No 1272/2008 and its subsequent adaptions, magnesium neodecanoate does not have to be classified and has no obligatory labelling requirement for sensitization by skin contact.

Magnesium neodecanoate is not classified for respiratory sensitisation because of lacking data.