An innovative, Raman spectroscopy‐based monitoring and control system is introduced in this paper for designing dynamic feeding strategies that allow the maintenance of key cellular nutrients at an ideal level in Chinese hamster ovary cell culture. The Partial Least Squares calibration models built for glucose, lactate and 16 (out of 20) individual amino acids had very good predictive power with low root mean square errors values and high square correlation coefficients. The developed models used for real‐time measurement of nutrient and by‐product concentrations allowed us to gain better insight into the metabolic behavior and nutritional consumption of cells. To establish a more beneficial nutritional environment for the cells, two types of dynamic feeding strategies were used to control the delivery of two‐part multi‐component feed media according to the prediction of Raman models (glucose or arginine). As a result, instead of high fluctuations, the nutrients (glucose together with amino acids) were maintained at the desired level providing a more balanced environment for the cells. Moreover, the use of amino acid‐based feeding control enabled to prevent the excessive nutrient replenishment and was economically beneficial by significantly reducing the amount of supplied feed medium compared to the glucose‐based dynamic fed culture.

The aim of this study was to develop antisense oligonucleotide tablet formulations using high-speed electrospinning. Hydroxypropyl-beta-cyclodextrin (HPβCD) was used as a stabilizer and as an electrospinning matrix. In order to optimize the morphology of the fibers, electrospinning of various formulations was carried out using water, methanol/water (1:1), and methanol as solvents. The results showed that using methanol could be advantageous due to the lower viscosity threshold for fiber formation enabling higher potential drug loadings by using less excipient. To increase the productivity of electrospinning, high-speed electrospinning technology was utilized and HPβCD fibers containing 9.1% antisense oligonucleotide were prepared at a rate of ~330 g/h. Furthermore, to increase the drug content of the fibers, a formulation with a 50% drug loading was developed. The fibers had excellent grindability but poor flowability. The ground fibrous powder was mixed with excipients to improve its flowability, which enabled the automatic tableting of the mixture by direct compression. The fibrous HPβCD–antisense oligonucleotide formulations showed no sign of physical or chemical degradation over the 1-year stability study, which also shows the suitability of the HPβCD matrix for the formulation of biopharmaceuticals. The obtained results demonstrate possible solutions for the challenges of electrospinning such as scale-up and downstream processing of the fibers.

The development of stable biopharmaceutical formulations, such as monoclonal antibodies, poses a great challenge in the pharmaceutical industry. This study investigated the stabilizing effect of 2-hydroxypropyl-β-cyclodextrin (HP-β-CD) in liquid and solid formulations of infliximab during processing and storage. The solid formulation was produced by a scaled-up high-speed electrospinning method, resulting in a product suitable for reconstitution with excellent dissolution properties. Liquid formulations contained exclusively HP-β-CD as a stabilizing excipient at different concentrations. Both types of formulations were stored under various conditions for up to 6 months, and infliximab stability was compared based on monomer recovery and the analysis of fragments and aggregates. The solid formulation stored at low (-18 °C, 4 °C) temperatures and lower humidity conditions show the most promising results. Moreover, the monomer loss was less than 10 % even at room temperature storage after 2 months, indicating a potentially good temperature tolerance. Increasing HP-β-CD content in liquid formulations significantly improved the long-term stability of infliximab while enhancing protection against mechanical stress. Furthermore, to better understand the stabilizing mechanism of HP-β-CD on infliximab, the molecular interactions were investigated by bio-layer interferometry and isothermal titration calorimetry methods. The experiments proved that the presence of HP-β-CD decreased infliximab self-interaction, correlating with the aggregation-suppressing effect of HP-β-CD observed during the stress- and long-term stability studies. The results demonstrate the potential of HP-β-CD as a stabilizing excipient in liquid and solid formulations of infliximab.

Research background. Protein A affinity chromatography is a well-established method currently used in the pharmaceutical industry. However, the high costs usually associated with chromatographic separation of protein A and the difficulties in continuous operation make the investigation of alternative purification methods very important. Experimental approach. In this study, extraction/back-extraction and precipitation/dissolution methods were developed and optimised. They were compared with protein A and cation exchange chromatography separations in terms of yield of monoclonal antibody (mAb) and amount of residual impurities, such as DNA and host cell proteins, and amount of mAb aggregates. For a comprehensive comparison of the different methods, experiments were carried out with the same cell-free fermentation broth containing adalimumab. Results and conclusions. Protein A and cation exchange chromatographic separations resulted in high yield and purity of adalimumab. The precipitation-based process resulted in high yield but with lower purity. The extraction-based purification resulted in low yield and purity. Thus, the precipitation-based method proved to be more promising than the extraction-based method for direct purification of adalimumab from harvested cell culture fluid. Novelty and scientific contribution. Although alternative purification methods may offer the advantages of simplicity and low-cost operation, further significant improvements are required to compete with the performance of chromatographic separations of adalimumab from true fermentation broth.