SLN Using Dual Centrifugation

Nanoparticles are increasingly used for the transport of active drug substances in the human body. For this purpose, the properties of the nanoparticles (size, material) must specifically be adapted to their purpose, which can be, for example, the slow release of the active ingredient in the body, rapid uptake in cells or the targeted transporter of active ingredients in tumors. A current example are the RNA vaccines against Covid-19, e.g. from BioNTech, which are nothing else than lipid nanoparticles that enable the uptake of the RNA vaccine into cells.

Lipid nanoparticles can ideally be produced by using the new dual centrifuge “ZentriMix 380 R” from Hettich. The recently developed process of dual centrifugation allows the preparation of very small and uniform nanoparticles in a very simple and fast way and is currently establishing itself as the quasi-standard of nanoparticle as well as nanocrystal production.

A promising group of nanoparticles are so-called "solid lipid nanoparticles", SLN for short, which are composed of solid components such as high-melting waxes or lipids. SLNs can bind water-insoluble drugs to and within the particle and transport them in the body. Because they are composed of solid material, SLN have a rather long lifetime in the body, which is the prerequisite for a long-lasting release of the active ingredients.

However, the structure of SLNs from solid components makes their production costly and lengthy. Usually SLNs are produced in large high-pressure homogenizers at high temperatures. A technique which is not available in all labs.

Dr. Denise Steiner (AG Prof. Bunjes) from the University of Braunschweig has succeeded in producing SLN even in small quantities and very quickly with the help of the ZentriMix 380 R and in producing up to 40 different formulations simultaneously, which greatly accelerates the development of SLN with tailor-made properties.

To make this possible, the ZentriMix 380 R was modified with a heating option by its manufacturer, Hettich. The new prototype does a great job. Sample temperatures of 90°C are realized. The process takes less than 15 minutes and the resulting SLN are very small (down to about 100 nm).

The work of Dr. Steiner and her team impressively demonstrates the particular suitability of dual centrifugation (ZentriMix technique) for the production of SLNs and has the potential to significantly progress the development of new and promising therapeutic nanoparticles.

The paper has been available for online viewing since June 2021: (