72 PRESERVATIVES
provided in Table 7), and indicate specific performance and therefore application suitability of the three blends. The sorbitan caprylate, potassium sorbate, and capryloyl/caproyl methyl glucamide blend is designed for preservation of a wide range of cosmetics and toiletries. Typical use concentrations are 0.5-1.5 % for most cosmetic formulations. It provides activity against Gram-positive and Gram-negative bacteria, yeasts and molds. It remains fully stable from pH 4.0-8.0 with best performance achieved at pH < 6 (4-5) due to the preservative potassium sorbate. As a liquid, it is easily incorporated into
formulations to be preserved. It has a rather low solubility in water and is readily miscible with many organic solvents, surfactants and emulsifiers.
The blend sorbitan caprylate and benzyl alcohol is suitable for a wide range of cosmetic and toiletry applications. It has typical recommended use concentrations of 1.0%-2.5% for most cosmetic formulations. It provides activity against Gram-positive and Gram-negative bacteria, yeasts and molds and retains activity in the presence of most cosmetic ingredients. It is slightly soluble in water, readily soluble in oil phase ingredients and in many organic solvents, and remains fully stable over a wide pH range from 4.0-8.0.
The blend of phenethyl alcohol, a fragrance alcohol, and sorbitan caprylate is designed for fragrance and preservation support of a wide range of cosmetics and toiletries. Typical use concentrations are 1.0%– 2.0% for most cosmetic formulations. It is compatible with most cosmetic ingredients and remains fully stable over a wide pH range from 4.0 to 8.0. It is slightly soluble in water, readily soluble in oil phase ingredients and in many organic solvents. The liquid is easily incorporated into the materials to be preserved.
Highly aqueous formulations Preserving a high aqueous formulation is traditionally a challenge as high water content promotes the growth of organisms. In addition to this, a lot of preservatives are rather hydrophobic and difficult to incorporate in the formulations in a stable way. The recent introduction of a sorbitan caprylate-based blend specifically for wipes
Table 7: MIC Minimum Inhibitory Concentration.
Preserving System Nipaguard SCL* Nipaguard SCA** Velsan SPA**
Nipaguard SCS** * Tested at pH 5 ** Tested at pH 7 PERSONAL CARE ASIA PACIFIC Pa
0.4 0.6 0.6
0.03 Sa 0.1
0.15 0.1
0.03
MIC (%) Ec
0.2 0.4 0.8
0.04
Ca 0.1 0.1 0.1
0.03
Ab 0.1
0.08 0.08 0.03
Table 6: Efficacy and stability Preserving
System (1% used) Nipaguard SCS
Phenoxyethanol + Paraben blend
Preservative Load
10%
Formulation Type
Wipes juice Rinse-off Lotion
100%
Wipes juice Rinse-off Lotion
and other high aqueous formulations is supporting safer and confident preservation for this application area. The key with this additional blend is to combine sorbitan caprylate with piroctone olamine, a well- established ingredient in the market with a long history of safe use, which is globally approved as a preservative. The synergistic broad spectrum blend of
piroctone olamine comprising sorbitan caprylate, (Nipaguard SCS) provides additional ease in formulating due to the added solubiliser system of capryloyl/caproyl methyl glucamide and trilaureth-4 phosphate. The blend provides efficacy and flexibility with a reduction in the overall amount of preservatives, as demonstrated in the following test. The blend was tested against a phenoxylethanol and paraben blend to demonstrate efficacy and stability in wipes juice, rinse-off and lotion formulation types. The results of the sample formulations in
Table 6 show effective broad spectrum preservation across product categories at a level of 1% of the blend. As the blend itself contains only 10% preservative loading, it offers formulators the option of an effective and more stable alternative compared to phenoxylethanol/paraben blend which has a 100% preservative load at 1% use-level in all the formulations, in particular for wipes and leave-on formulations. The antimicrobial agent exhibits
microbial activity against a wide range of bacteria, yeast and molds and is active within a broad pH range of 4.0-8.0. Typical use concentrations are 0.75% - 1.0%. Table 7 provides an overview of the
preservative efficacy assessed by MIC of all four sorbitan caprylate-based products referenced in this discussion. All products can be used to protect a formulation
Efficacy Stability pH 7 pH 4.5 pH 7 pH 4.5
50˚C
against all organisms, and are especially valuable against yeast and mold.
Conclusions The four featured sorbitan caprylate blends belonging to Clariant’s Nipaguard Zero portfolio offer a good alternative to parabens at comparable costs and effectiveness, and to formaldehyde and halogen-containing preservatives. Their effectiveness at low concentrations supports reduced usage levels of preservatives in formulations, and as liquids they are easy to incorporate into a wide range of cosmetics. Especially for the field of natural cosmetics, that follows the established green certifications like Cosmos, sorbitan caprylate and its blends are expanding the options for choosing the right preservative.
Extensive testing according to high
standards (Ph. Eur.) and the focus on sustainable ingredients, creates confidence for formulators looking for a broader toolbox of preservatives to pursue different product claims and certifications, and to balance their needs with consumer requirements.
PC
References 1 Ernst & Young consultants assessment based on figures of Cf. L’Oréal: The World of Beauty in 2014, 2014, available online at www.loreal-
finance.com, accessed on 03.12.201
2 Cf. WebMD: Allergies Health Center:Skin Reactions to Beauty Products, undated, available online at
www.webmd.com, accessed on 22.12.2015
3 Cf. Vanessa Ngan: Cosmetics allergy, DermNet NZ, undated, available online at
www.dermnetnz.org, accessed on 23.12.2015
4 Cf. Bundesinstitut für Risikobewertung (BfR) [German Federal Institute for Risk Assessment]: Verwendung von unverdünntem Teebaumöl als kosmetisches Mittel, 01.09.2003, p. 1, available online at
www.bfr.bund.de, accessed on 23.12.2015
5 Cf. Making Skincare: Reviews of 27 Preservatives, undated, available online at
www.makingskincare.com, accessed on 23.12.2015
6 Cf. Environmental Defense Fund Smart Innovation: The Opportunity for Safer Preservatives. Preservation Innovation Project (PIP) May 24, 2017
November 2017
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