Product protection and active ingredient at the same time - is that possible?

Cosmetics are everyday products that contribute to care and well-being. However, they must also fulfill legal requirements and be safe for the consumer. Microbiological safety is therefore an important aspect.

What exactly does "microbiological safety" mean?

Microorganisms can spread particularly in personal care products that contain water and other nutrients such as protein. These include emulsions or surfactant products, for example. If cosmetics are not sufficiently protected against microbial contamination, there is a possibility that they will become infested with these microorganisms. Contamination can lead to an unpleasant odor, discoloration or a change in consistency. And some of these bacteria, yeasts or fungi can also cause problems for the skin and thus affect the safety of consumers.

When choosing the right antimicrobial agent, in addition to skin compatibility and antimicrobial effect, the following guideline is also important: as much as necessary, as little as possible. In the best case, this means a substance with a broad-spectrum effect that is effective even in very low concentrations. Such substances are called preservatives.

What are preservatives?

Only substances whose safety has been comprehensively tested at EU level are approved as preservatives. They are examined for their toxicological safety and subjected to comprehensive tests before being approved. Manufacturers must prove their harmlessness to health in extensive scientific studies. These approved preservatives therefore have a comprehensive toxicological dossier.

In summary, the ideal antimicrobial agent should therefore have high antibacterial activity and at the same time be safe for humans and the environment. In addition, these substances should also meet the consumer's desire for more naturalness and, if possible, be based on naturally occurring raw materials^{1, 2, 3} .

SEPICIDE™ G - Bio-based preservative

Taking these desired properties into account, ethyl lauric arginate HCl (ELA), which is obtained from the natural building blocks lauric acid and the amino acid L-arginine, is an interesting option. It inhibits the proliferation of microorganisms such as bacteria, fungi and yeasts by disrupting their cell membrane potential, altering cell permeability and thus causing the loss of cell viability.

Dissolved in glycerine, it is a liquid, clear and water-soluble broad spectrum preservative called SEPICIDE™ G. It is effective against GRAM+, GRAM- bacteria as well as mold and yeast in a pH range between 3-7 and is a natural way to preserve your formulation. Furthermore, it is Cosmos & Natrue certified, 100% natural according to ISO 16128 and China approved. It is also an easily biodegradable product that does not irritate the skin.

Figure 1: structure of SEPICIDE™ G

SEPICIDE™ G - Biobased active ingredient

Thanks to its global effect on microorganisms such as Corynebacterium xerosis, Propionibacterium acnes and Malassezia furfur, SEPICIDE™ G is the perfect active partner for deodorant, skin cleansing and anti-dandruff care and also has an antimicrobial effect in oral care, e.g. in mouthwash.

For the deodorant effect, Corynebacterium xerosis bacteria, which cause bad odor as commensals, were measured. Six formulas with different active ingredients (triethyl citrate 3%, ethylhexyl glycerin 1%, triclosan 0.3% or SEPICIDE™ G at 1% or 2%) were tested vs. control (same formula, without active ingredient) and the Corynebacterium xerosis bacteria were measured after 30 min, 2 hours & 24 hours. SEPICIDE™ G at a concentration of 1% and 2% inhibited C. xerosis better than classic deodorants.

For the skin cleansing effect, Cutibacterium acnes bacteria, which as commensals contribute to blemished skin and skin imbalance, were measured. Three formulas with different active ingredients (salicylic acid at 0.4% and 2%, SEPICIDE™ G at 2%, gluconolactone at 1.5% or 7.5%) were tested vs. control and the activity of Cutibacterium acnes was measured after 30min, 2h & 72h. SEPICIDE™ G at a concentration of 2% is much more active and efficient than salicylic acid and shows very good efficacy in cleansing acne-prone skin.

For the anti-dandruff effect, the fungus Malassezia furfur, which leads to dandruff as well as itching and redness of the scalp when it grows excessively, was measured. Anti-dandruff shampoos were evaluated with a surfactant base and various active ingredients (0.4% zinc pyrithione, piroctone olamine at 0.4% or 0.8% and ELA at 0.4% (= 2% SEPICIDE™ G) in comparison to the control (same formula, without active ingredient) and Malassezia furfur after 10 min, 15 min and 2h. At 2%, SEPICIDE™ G shows good activity on Malassezia furfur comparable to the references. This anti-dandruff effect was confirmed in an in-vivo test.For the anti-dandruff effect, the fungus Malassezia furfur, which leads to dandruff as well as itching and redness of the scalp when it grows excessively, was measured. Anti-dandruff shampoos were evaluated with a surfactant base and various active ingredients (0.4% zinc pyrithione, piroctone olamine at 0.4% or 0.8% and ELA at 0.4% (= 2% SEPICIDE™ G) in comparison to the control (same formula, without active ingredient) and Malassezia furfur after 10 min, 15 min and 2h. At 2%, SEPICIDE™ G shows good activity on Malassezia furfur comparable to the references. This anti-dandruff effect was confirmed in an in-vivo test.

In oral care, SEPICIDE™ G can be used in mouthwash or mouth rinse. It rapidly kills various microorganisms in the oral cavity. SEPICIDE™ G has an optimal surface effect and prevents the adhesion/attachment of bacteria and their further multiplication. It also reduces biofilms on teeth/gums (in vivo). The anti-plaque effect is comparable to that of traditional benchmarks, especially in combination with zinc lactate.

SEPICIDE™ G Formulation notes

SEPICIDE™ G is liquid, water soluble, heat and shear resistant and can therefore be easily used in the right matrix at every step of the production process. SEPICIDE™ G works excellently in natural based, non-ionic toners etc.

However, due to the cationic nature of SEPICIDE™ G, it is responsible for some interactions with anionic raw materials, e.g. in products with anionic surfactants or emulsions with anionic thickeners. This interaction reduces the antimicrobial efficacy of SEPICIDE™ G, but by combining it with other antimicrobial active ingredients, this interaction can be reduced and a synergistic effect can be achieved.

SKIN-FRIENDLY MICELLAR WATER (EU07715)

Summary

Preservatives are required for the microbiological safety of cosmetic products. SEPICIDE™ G is a natural preservative with good skin compatibility. It is effective in the antimicrobial broad spectrum, which is efficient even at low application concentrations.

In addition to its preservative effect, thanks to its antimicrobial properties it also shows other efficacies and can therefore be used in many ways: e.g. in facial care for acne-prone skin, in deodorants, in hair care (anti-dandruff, conditioner) & in oral care (antimicrobial and anti-plaque effect).

¹ https://www.ikw.org/schoenheitspflege/wissen/warum-kosmetische-mittel-konservieren

²https://www.gdch.de/fileadmin/downloads/Netzwerk_und_Strukturen/Fachgruppen/Lebensmittelchemiker/Arbeitsgruppen/kosmetik/Konseriverung_Kosmetik_deutsch.pdf

³ https://cosmileeurope.eu/de/inci/inhaltsstoff/5385/ethyl-lauroyl-arginate-hcl/