Compaction of chemically defined cell culture media increases its dissolution rate through an increase of solvent accessible surface area

Abstract

Cultivation of mammalian cells for the generation of therapeutics requires the use of cell culture media which is a defined mixture of nutrients including carbohydrates, amino acids, lipids, vitamins, and inorganic salts. Its composition influences the cell density, yield, and quality of the molecule expressed. These chemically defined cell culture media are manufactured as powders since they offer advantages of storage, handling and stability. To prevent de-mixing of the powders and maintain homogeneity, these powders are milled down to small particle size ranges. However, this small particle size allows for inter-particle forces to impact powder flow properties, and decreases the surface area available to dissolution. Hence a method is required that improves these powder parameters, without altering their composition. A deeper understanding of the dissolution mechanism of multicomponent mixtures like cell culture media is also needed. Here, cell culture media granules, generated from homogeneous powders by roller compaction are evaluated. The granulation process did not alter the composition of the media and properties of solutions generated thereof. The analysis and comparison of the dissolution profile of powder and compacted media enabled the calculation of the actual surface area available to dissolution. The improvement in granule dissolution can be attributed to dispersion and disintegration of the granules on wetting increasing available surface area. Decrease in inter-particle forces in granules also improves flow-ability properties. Surface character and pores on the granules further augments the improvement in dissolution.

Media on‐demand: Continuous reconstitution of a chemically defined media directly from solids

“…This continuous on‐demand reconstitution of CDM can substantially shrink auxiliary buffer and media tanks needed for continuous upstream production like perfusion systems. Undoubtedly, CDM differ significantly in their powder characteristics and flow behavior from buffer species commonly used in the biopharmaceutical industry simply due to their more complex formulations and manufacturing (Fike et al, 2001 ; Salazar, Bleifuß, et al, 2016 ). In contrast, most used buffers in the biopharmaceutical industry, are consisting of a few salts (Carredano et al, 2018 ).…”

“…Nevertheless, we think that applying the system to other media requiring pH‐adjustment is possible, as in‐line pH adjustment has been demonstrated successfully already at an industrial scale. Nevertheless, the system developed described herein is currently limited by not being a fully closed system and without any environmental control, which would be pivotal for an industrial application due to reasons for dust control, the risk of contamination, and potential degradation of components, but it would be out of the scope of the proof of concept (Matheson, 2005 ; Salazar, Bleifuß, et al, 2016 ; Sheraz et al, 2014 ). Monitoring of the degradation of dry powder media components during storage in the hopper could be conducted by colorimetry as recently shown by Dickens et al ( 2020 ).…”

Effect of particle size distribution on filtration performance of cell culture medium

“…13 For powdered media, good dissolution is critical in cell culture media preparation, as this will impact sterile filter capacity, and will ensure that there is no impact on cell culture performance in terms of viable cell density and final product titers in manufacturing. 14 Sterile filtration capacity may also vary based on the cell culture media formulation. 15 Differences in the filtration processing are believed to be due to different raw components provided by the supplier and nonhomogeneity during the hydration processes that take place in each batch.…”

“…For powdered media, good dissolution is critical in cell culture media preparation, as this will impact sterile filter capacity, and will ensure that there is no impact on cell culture performance in terms of viable cell density and final product titers in manufacturing 14 . Sterile filtration capacity may also vary based on the cell culture media formulation 15 .…”