Characterization of a convection-based support microstructure through a flow resistance parameter

Predictive scaling of fiber-based protein A capture chromatography using mechanistic modeling

Protein A affinity chromatography is an important step in the purification of monoclonal antibodies (mAbs) and mAb-derived biotherapeutics. While the biopharma industry has extensive expertise in the operation of protein A chromatography, the mechanistic understanding of the adsorption/desorption processes is still limited, and scaling up and scaling down can be challenging because of complex mass transfer effects in bead-based resins. In convective media, such as fiber-based technologies, complex mass transfer effects such as film and pore diffusions do not occur which facilitates the study of the adsorption phenomena in more detail and simplifies the process scale-up. In the present study, the experimentation with small-scale fiber-based protein A affinity adsorber units using different flow rates forms the basis for modeling of mAb adsorption and elution behavior. The modeling approach combines aspects of both stoichiometric and colloidal adsorption models, and an empirical part for the pH. With this type of model, it was possible to describe the experimental chromatograms on a small scale very well. An in silico scale-up could be carried out solely with the help of system and device characterization without feedstock. The adsorption model could be transferred without adaption. Although only a limited number of runs were used for modeling, the predictions of up to 37 times larger units were accurate.

Influence of porosity and microstructure on compression behavior of methacrylate polymers in flow-through applications

Mechanical properties of a material play a pivotal role in its performance when such porous material is used in a flow-through mode. This study delves into the effect of porosity and microstructure on the compressibility of methacrylate polymer, focusing on two distinct microstructures: cauliflower and high internal phase emulsion. Samples with various porosities yet identical chemical composition were prepared and their Young's modulus was measured. The effect of porosity on Young's modulus was described by an exponential law model with the cauliflower microstructure exhibiting an exponent of 3.61, while the high internal phase emulsion of only 1.86. A mathematical analysis of the compression caused by a liquid flow unveiled significant disparities in the porosity threshold where minimal compression is observed, being around 0.45 for the cauliflower while there is monotone decrease in compression with porosity increase for the high internal phase emulsion microstructure. Evaluating exponent integer values between 1 and 5 over entire porosity range reveals that the porosity where the minimal compression occurs increases with a decrease in exponent value, being approximately 0.33 for n = 5, 0.4 for n = 4, 0.55 for n = 3, 0.65 for n = 2 while no minimum occurs for n = 1. These findings indicate that lower exponent value results in lower compression under identical experimental conditions.

Current research approaches in downstream processing of pharmaceutically relevant proteins

Biopharmaceuticals and their production are on the rise. They are needed to treat and to prevent multiple diseases. Therefore, an urgent need for process intensification in downstream processing (DSP) has been identified to produce biopharmaceuticals more efficiently. The DSP currently accounts for the majority of production costs of pharmaceutically relevant proteins. This short review gathers essential research over the past 3 years that addresses novel solutions to overcome this bottleneck. The overview includes promising studies in the fields of chromatography, aqueous two-phase systems, precipitation, crystallization, magnetic separation, and filtration for the purification of pharmaceutically relevant proteins.