A REASONABLE APPROACH TO MODERN PRESERVATION

From a regulatory perspective, preservative is a substance that is added to a formulation to prevent spoilage caused by microorganisms. Europe and many countries like Japan and China regulate cosmetic preservatives by having a positive list of substances that are allowed to be used as preservatives. The list includes chemicals such as parabens, formaldehyde
donors (DMDM hydantoin & quaternium-15), isothiazolinones, aromatic alcohols (phenoxyethanol & benzyl alcohol) and
organic acids (benzoic & sorbic acids).

Due to the negative press on many conventional chemistries, regulatory changes and consumer demand, the list of
chemicals approved as preservatives, is getting shorter. This has prompted cosmetic industry to look for alternative ways
of preservation of cosmetics. The modern way of cosmetic preservation involves not only the use of conventional
preservatives but also multifunctional ingredients, chelating agents and antioxidants. At Symrise, we call the modern way
of preservation as product protection.

Cosmetic formulators are also looking into other industries for new ideas to help preserve products. Hurdle technology,
conventionally used for preservation in food industry, has always been of interest. It involves creating a higher hurdle
for microbial contamination/growth by adjusting the pH (high/low) of the formula, reducing water activity, using
fragrance containing essential oils and/or changing the packaging to reduce/eliminate direct contact of the cosmetic product in the bottle.

There are different methods to evaluate the preservative efficacy of cosmetic products. The most common are that based on European Pharmacopoeia (EP), United States Pharmacopoeia (USP), ISO and PCPC (Personal Care Products Council, formerly CTFA), though some manufacturers have their own in-house protocols that are mostly modified forms of the methods mentioned above. All methods essentially test the product containing the protection system against the same set of microorganisms: gram negative/positive bacteria, yeast and mold. Some manufacturers also test the efficacy against incidental microorganisms and/or “house bugs”.

In spite of the fact that the list of preservatives is getting shorter, cosmetic industry has not seen many new molecules being introduced for product protection. Various registrations like European REACh & regional chemical inventories and animal testing ban have tremendously reduced the appetite of chemical suppliers to invest in the research and development of new preservatives. This has reduced the rate of innovation in the area of cosmetic preservatives, so much that only a handful of preservatives have been launched over the past 20 years.

The regulatory changes as well as modern consumer needs have led to several trends in the area of cosmetic
preservation, like:
• use of multifunctional ingredients
• green/naturality/sustainable claims
• elimination of chemicals (like parabens and isothiazolinones), that are under discussion at the consumer level
• use of eco-friendly ingredients
• waterless formulations.

The list of product protection ingredients with high naturality index is very short. Often organic acids like sorbic acid and
potassium sorbate are used in combination with green materials like pentylene glycol and glyceryl caprylate to protect cosmetic formulations effectively.

In general cosmetic chemists face an increasing challenge to formulate products that meet the consumer demand since the
preservative tool box is shrinking. Since some of the remaining chemicals like phenoxyethanol, benzyl alcohol and organic
acids, don’t have a broad spectrum of efficacy, they have to be combined with other materials, which also results in higher cost.

Gone are the days when preservation of a cosmetic product was an afterthought. We advise cosmetic formulators to
select the product protection system one at a time so that the formula is well preserved while meeting the demand of
modern consumers. An essential aspect of this would be to use of a combination of two or more ingredients, rather than
using one at the maximum dose. Multifunctional ingredients are a key to modern product protection since they provide
several benefits like moisturization, emolliency, co-emulsification, etc., that would help reduce the overall cost of the formulation.

This article has been published as part of a "Panel discussion" on Cosmetic preservation in the H&PC (Household and Personal Care journal). For the full article please review the HP&C Journal of September / October 2019.

The interview was given by Yohanna Sander, Director, Global Product Management, Product Protection, Cosmetic Ingredients Division at Symrise.

» Discover the Symrise Product Protection portfolio of Preservatives and Multifunctionals.