Eliminates all bacteria and yeast after 7 days and moulds after 28 days

0.7% Cosphaderm Dicapo natural Tested in day cream at pH 6.5


1000000 100000 10000 1000 100 10 1

0 2 7 14 Figure 5: Challenge test results of 0.7 % Cosphaderm® Dicapo natural tested in day cream.

or too low a pKa value. Luckily, others have been proven to be an effective addition to the formulator’s toolbox for preservation systems. With our raw materials Cosphaderm LA-T, pAS natural, CA natural and AS, we are able to offer a wide range of single actives from this segment. As well as this, we also provide some salts of certain acids to broaden the scope of application: Cosphaderm Sodium pAS natural and a blend with broad spectrum efficacy Sodium LAAS.

Alcohols, diols and polyols Some members of this group have evidently been known for thousands of years. Ethanol can be used for preservation. However, high dosages are needed and such dosages for the most part do not fit into the cosmetic concept. In the last few decades, two much-valued vicinal alcohols (diols) became more and more popular. For these products, much lower concentrations are needed for a strong antimicrobial efficiency. Another famous group consists of the aromatic alcohols like benzylalcohol, phenol derivatives or phenoxyethanol. At the time, they were often used in cosmetic products. Because of their side effects and some restrictions, nowadays they are rarely added to new formulations. In modern cosmetic concepts the diols form the most important group due to their ability to attack the membrane of germs. Nevertheless, their water solubility and their antimicrobial efficiency are

Water solubility Octiol

different and always need to be evaluated and adapted to the specific formulation. The next figure (Fig 6) compares the water solubility with the antimicrobial efficiency. Because of their ability to weaken the

membrane of germs, they are highly suitable to those partners that need to pass the microbial membrane (like organic acids). Additionally, they can also function as a solvent for hydrophobic extracts. Some diols are soluble in oil and water, which is a great benefit. Based on solubility, the water phase is an added benefit in terms of oil- soluble but highly efficient antimicrobial extracts – like Cosphaderm Magnolia Extract 98. Besides the diols there is one more group of

surface-active molecules available: monoesters. Long chain monoesters (e.g. glyceryl stearate) are often used as co-emulsifiers, but short chain esters show an antimicrobial effect. Glyceryl caprylate, glyceryl caprate and glyceryl laurate are well established for this purpose. Many of the above-mentioned products are available in natural quality, and are additionally approved by certification bodies like COSMOS/ECOCERT or NaTrue. Such products can be found under the following brand names Cosphaderm Propanediol natural, Pentiol natural, GMCY, Gemix, Pentiol GL, Hexiol and Octiol.

Natural extracts and essential oils There are certain natural extracts that exhibit

strong antimicrobial effects. Most of them need to be combined with a diol or a monoester because they are insoluble in water. The mode of action of extracts can be very different. Some contain organic acids, others attack the metabolism of germs and some might go on to act in different ways. One well-known example is Cosphaderm Magnolia Extract 98. This extract from the magnolia officinalis bark shows excellent fungicidal activity already at a concentration of 0.2 %. This is due to the extremely high content (98 %) of active matter in the extract.

Conclusion on how to improve preserving systems in cosmetics In conclusion, modern cosmetic products no longer need the typical and listed preservatives. Replacing much-discussed controversial chemicals creates a win-win situation for both the cosmetic manufacturer and final consumer. The number of positive effects can be increased and negative side effects decreased. Rating platforms and information tools simplify matters such that each consumer can gain a deep insight into cosmetic products. More and more consumers are looking for greener products, and thus replacing common preservatives with multifunctionals is one important step in fulfilling these needs. Without doubt, it is not always easy to find the best antimicrobial system for your specific formulation.

ABOUT THE AUTHOR Hexiol Pentiol Propanediol Antimicrobial efficiency

Figure 6: Overview of Cosphaderm® Diols and a comparison of their water solubility and antimicrobial efficiency.

Dr Carsten Dietz, Sales Director at Cosphatec GmbH, is responsible for the Asian Pacific region, head of sales for the Cosphatec Shanghai subunit and sales director for East Europe. In 2013 he joined Cosphatec as R&D manager and was promoted to R&D director. After five years in this position, he changed to the sales department in 2019. Mr Dietz studied biochemistry in Mainz, Germany, and did his PhD as part of the excellence programme of the Max Planck Institute in the field of plant physiology and physical chemistry at the ETH Zürich.


28 E.coli ■ P. aeruginosa ■ S. aureus ■ C. albicans ■ A. brasiliensis ■


Cfu (log scale)


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