In the fast evolving world of beauty and skincare, innovation often pushes formulations into new territory. Nanoemulsions, microemulsions and advanced delivery systems are now central to product strategies for brands that want superior sensory profiles, enhanced penetration and elevated performance. Yet as formulations become more sophisticated, so do the challenges behind the scenes. One of the most underestimated challenges is the preservation of systems that contain a high concentration of nonionic surfactants.
A recent scientific study offers valuable insight into how preservatives behave in these modern systems and why many traditional approaches fail. For formulators, regulatory teams and brand leaders, understanding these interactions is essential for product safety, stability and commercial success.
At Olalla Consulting, we support brands and manufacturers in navigating exactly these complexities. This article breaks down the key findings of the research and translates them into practical guidance for real world product development.
Nanoemulsions and microemulsions rely on significant levels of polyethoxylated surfactants such as polysorbate 80 and hydrogenated castor oil. These ingredients create elegant textures and stable structures, but they also interact with preservatives in ways that reduce antimicrobial activity.
The study found that:
This is especially true for parabens, which are widely used in cosmetic preservation but are known to be sensitive to interactions with highly ethoxylated materials.
For brands working with advanced emulsions, this means that a preservative system that performs perfectly in a standard cream may fail entirely in a nanoemulsion.
The research confirmed what many formulators have observed in practice. Parabens such as methylparaben and blends containing methyl, ethyl, propyl, butyl and isobutyl parabens lose their effectiveness when combined with high levels of polysorbate 80 or hydrogenated castor oil.
In the study:
This is a clear indication that parabens become unavailable due to micellar solubilisation or binding to surfactant structures.
For brands still relying on paraben systems, this is a critical reminder that compatibility testing is not optional. It is essential.
The study also evaluated two paraben free systems:
These systems performed better overall, although not universally. Phenoxyethanol based blends were less affected by surfactant interactions, but still showed reduced performance in certain conditions.
Key findings include:
This reinforces the need for tailored preservation strategies rather than relying on standard usage levels.
One of the most important insights from the study is that preservative performance in isolation does not predict performance in a finished formulation.
A preservative may pass compatibility testing with individual excipients but still fail once incorporated into a complex emulsion. This is because:
This is why at Olalla Consulting we always recommend challenge testing on the final formulation, not on a theoretical model or simplified base.
If you want support with challenge test planning or preservative strategy, you can explore our Regulatory and Compliance Services on the Olalla Consulting website.
For brands developing modern emulsions, the implications are clear:
Their antimicrobial activity is significantly reduced, making them unreliable for nanoemulsions and microemulsions.
Phenoxyethanol based blends are more robust but not universally effective.
Single molecule systems rarely provide broad spectrum protection in advanced emulsions.
There is no one size fits all solution. Preservation must be designed around the specific surfactant system, oil phase and processing method.
This is not just a regulatory requirement. It is a brand protection strategy.
If you want to learn more about formulation optimisation, you can visit our Formulation Development page at Olalla Consulting.
With decades of experience across formulation science, regulatory compliance and brand development, Olalla Consulting helps companies create safe, stable and commercially successful products.
We support you with:
If you are developing a high surfactant formulation or planning to introduce nanoemulsion technology into your product line, our team can help you design a preservation system that is both effective and compliant.
If you want expert guidance on preservative selection, formulation optimisation or regulatory compliance, Olalla Consulting is here to support you.
Visit our website to explore our services or contact us directly to discuss your project.
Your next breakthrough deserves the right scientific foundation. Let us help you build it.