/Over the last decade, the pharmaceutical industry has increasingly shifted its focus from traditional
small-molecule drugs to biopharmaceuticals. However, developing and manufacturing the latter
comes with several challenges, one of the biggest being their successful formulation. Refrigerated
or even frozen transport and storage is the most straightforward solution, but it can be challenging,
costly, and energy-consuming – especially in countries with warmer climates. As a result, over 40% of
biopharmaceutical drug products are freeze-dried to increase their stability and shelf life, as well as
deliver a workable supply chain.
Pharmaceutical batch freeze-drying is a time-consuming, inefficient, energy-consuming, expensive, and
poorly controlled process that has been used for over 50 years. However, a continuous freeze-drying
technique has been developed to address these issues.
One significant difference between batch and continuous freeze-drying occurs during the freezing, where
liquid solution-filled vials are rotated along their longitudinal axis during a so-called spin freezing step
(Fig. 1). The liquid spreads over the vial wall due to centrifugal forces, creating a thin, uniform frozen
product layer with a higher surface area that is much thinner than the product layer obtained during
batch freeze-drying. That produces a sublimation rate up to twenty times higher than conventional
freeze-drying methods because of the large surface area, resulting in a much shorter drying time and
making it compatible with continuous processing. Furthermore, the applicable cooling and freezing rates
are much faster compared to batch freeze-drying. That can be very relevant for certain types of biologics,
such as mRNA LNPs.
