Natural multifunctional additives to fulfil your preservative needs

Blog Archive | 5 minutes  | Author: Kulvinder Kaur , MChem.

Introduction to preservatives

Cosmetic products mainly consist of oil and water emulsions; these offer ideal conditions for microorganism growth and therefore need to be preserved.  Without preservatives, all cosmetics would have a short shelf life and would have to be stored in a fridge. Preservation is achieved by selecting compatible antimicrobial ingredients that offer the best efficacy for the formulation.

 

So how do we select which preservative to use?

In Europe, legislators created a list of approved preservatives in Annex V of the EU Cosmetic Regulation. Many countries outside of Europe e.g. China, Australia and New Zealand, have also adopted Annex V for their own regulatory system.

Today the number of listed preservatives has been restricted because many of the ingredients also give rise to skin irritation or sensitising properties.  For example, chloroacetamide (Figure 1) is currently listed in Annex V to Regulation (EC) No 1223/2009 and allowed at concentrations up to 0.3 %. In 2010, Chloroacetamide was classified as a category 2 CMR substance under Regulation (EC) No 1272/2008 meaning that it is suspected carcinogenic (H341), mutagenic (H351) or toxic to reproduction (H361). In 2011, the Scientific Committee on Consumer Safety (SCCS) issued a scientific opinion on Chloroacetamide which concluded that substance is unsafe even when used in a concentration of up to 0.3 % w/w in cosmetic products.(1)

Therefore, for many years now, cosmetic formulators have questioned: “What is the right preservative system?”. With the ban on animal testing in the Cosmetic Regulation, the development of new preservatives is extremely difficult.

Figure 1. Lifecycle of chloroacetamide

 

Natural multifunctional additives as a solution

Our solution is to use natural multifunctional additives. Aevum Vita 406 and Aevum Vita 300 are 100% natural ingredients that have powerful antimicrobial properties in addition to offering further benefits to cosmetic products.  As they are not listed under Annex V, these multifunctional additives offer formulators a simple and safe solution to address all demands of a preservative without being labeled as a preservative; allowing formulators to label their products without preservative.

 

Aevum Vita 406

INCI: Sodium Caproyl, Lauroyl Lactylate and Sodium Citrate

Aevum Vita 406 is a blend of natural ingredients that offer excellent preservation of cosmetic formulations at 1 - 1.5% additions without the need for additional synthetic preservatives. Table 1 below shows its antimicrobial efficacy against certain bacteria.

Interestingly, Aevum Vita 406 completely inhibits Propionibacterium acnes, the bacteria that produces acne on skin, at concentrations of only 0.25%. The industry benchmark for an anti-acne active is salicylic acid. Reports on assays show that 0.4 - 0.8% is the minimum inhibitory concentration (MIC) required for salicylic acid to be effective against P. acnes.(2)  Therefore, Aevum Vita 406 can be used as an alternative to salicylic acid and as it is naturally derived, it will not irritate the skin.

 

Table 1. showing the efficacy of Aevum Vita 406 against bacteria.

 

Other beneficial properties of Aevum Vita 406 include its ability to produce a stable foam therefore can be used as a natural surfactant.  Foam stability was tested against industry standards Sodium Lauryl Sulphate (SLS) and Tween 80 (polysorbate 80). Each product was made into 1% aqueous solutions and shaken vigorously for 30 seconds to establish maximum foam height. The foam height was measured hourly thereafter. As you can see from Figure 2, the foam stability of Aevum Vita is comparable to Tween 80 which is also a natural surfactant. Currently, there are no natural surfactants that give the same level of performance to SLS however due to popular perception of SLS, it is important to find natural alternatives. To increase its performance, Aevum Vita 406 can be used as part of a surfactant blend. Typical addition levels of surfactants range between 5 and 30% and with this concentration of Aevum Vita 406, your formulation will also be completely preserved thus offering multiple benefits.

 

Figure 2. showing the foam height of Aevum Vita 406 (green), Tween 80 (blue) and SLS (orange) in one-hour intervals over five hours to test their foam stability. 

 

Aevum Vita 300

INCI: Aqua, Lactic acid, Phenylpropanol, Citric acid, Tartaric acid and gluconic acid

Similar to Aevum Vita 406, Aevum Vita 300 also displays powerful antimicrobial properties. Its performance is demonstrated in Figure 3 which displays the results of a challenge test carried out on a wet wipe containing 1.2% of Aevum Vita 300 at pH 5.5. Challenge testing is a study that simulates contamination through a series of inoculations containing microorganisms that are likely to be present in a product. It assesses the ability of a preservative to reduce or eradicate these organisms.(3)

The challenge test was carried out according to the EU Pharmacopeia standard so was conducted over a 28-day period. A wet wipe was chosen over other cosmetic products as wet wipes are considered to be the most difficult products to preserve. The pH was also chosen to demonstrate the high performance of Aevum Vita 300 as several preservatives lose their efficacy as pH increases.  From the results, it is clear that Aevum Vita 300 effectively preserves the wet wipe.

 

Figure 3. showing the challenge test results of Aevum Vita 300 formulated into a wet wipe.

 

As well as being a strong antimicrobial ingredient, Aevum Vita 300 also offers odour-masking properties due to the presence of phenyl propanol. The alcohol gives rise to a pleasant smell that can overpower other odours in the formulation. In addition, Aevum Vita 300 can be used as a natural and mild exfoliator therefore offering many benefits to your formulation.

 

If you are struggling to find natural alternatives to preservatives or are concerned that your current synthetic preservative may be at risk of becoming restricted, please contact Lawrence Industries for further information or request a sample.

 

References:

1. https://ec.europa.eu/health/scientific_committees/consumer_safety/docs/sccs_o_053.pdf

2. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6787063/

3. http://www.blutest.com/news/preservative-efficacy-testing

 

Author: Kulvinder Kaur , MChem.

Kulvinder studied Chemistry at the University of Leicester, where she obtained a first class degree. She looks after all of the industry sections across England and Wales.