The Impact of Surfactant Structures and High-Speed Mixing Dynamics in Achieving Nano-Sized Emulsions with Simple High-Speed Homogenization.

Purpose: This study investigates the impact of various mixing parameters and surfactant combinations on the physical characteristics of nanoemulsions produced using high-speed homogenization. Nanoemulsions are explored for their capacity to enhance transdermal drug delivery in pharmaceutical and cosmetic contexts.

Methods: Employing a standard high-speed homogenizer typical in the cosmetic industry, we tested different combinations of Polysorbate (Tween®) and Sorbitan ester (Span®) surfactants under single and intermittent process configurations. Key parameters assessed included particle size, size distribution, Oswald ripening, and creaming index.

Results: Nanoemulsions synthesized had particle sizes below 200 nm and appeared as white liquids with slight creaming. Extended mixing times were associated with smaller droplet sizes and reduced creaming. Both processing methods yielded similar nanoemulsion properties, indicating minimal impact from the type of process used. The nanoemulsions exhibited polydispersity indices ranging from 0.3 to 0.5, suggesting a uniform size distribution, and showed negligible Oswald ripening, which indicates stable droplet sizes over time.

Conclusion: The study confirms that precise control of mixing parameters and the selection of appropriate surfactant pairs are more critical than the choice of process in producing stable nanoemulsions. With efficient use of standard high-speed homogenizers, stable nanoemulsions suitable for large-scale production can be achieved, providing a cost-effective method for pharmaceutical and cosmetic industries.