Advanced strategies to enhance the performances of crystallization and precipitation of biopharmaceuticals

Abstract

Recent years have seen significant growth in the production titer of upstream of biopharmaceuticals, a level that could lead to diminishing returns upon increasing due to the downstream processing (DSP) bottleneck. The capture and polishing steps, representing the most laborious and expensive aspects of the DSP, are currently mainly dominated by pack-bed chromatography. However, due to the high cost of adsorbent and the high operation expenditure of chromatography-based theology, anything but chromatography (ABC) methodologies started to gain interest in the field as alternative method for purifying biopharmaceuticals. Precipitation and crystallization are classic unit operations that can provide promising alternatives in DSP. The aim of this dissertation is to develop advanced crystallization and precipitation strategies to improve process efficiency and product quality of biopharmaceuticals using bioactive Van glycopeptide and protein LYZ as the model biopharmaceuticals In the first study, we investigated the phase behavior of salting-out roomtemperature crystallization of glycopeptide antibiotics to determine crystallization conditions (i.e., pH, salt and peptide's concentrations, incubation time) to avoid needle-shaped crystal formation. Batch crystallizations of the prominent crystal habits identified from the phase behavior study (i.e., needle and non-needle) were subsequently performed. The batch crystallization's products were evaluated in their production yield and capacity, purity, size distribution, thermal stability, interfacial water content, dissolution profile, and antibiotic activity. The results showed that octahedral crystals were the predominant habit produced across the range of pH, salt, and peptide concentrations investigated. Needle crystal formation could be avoided by precise controls of pH and salt concentration. Octahedral crystals were produced at a significantly higher yield than needle crystals. The octahedral and needle crystals exhibited many similar properties but with distinct thermal stability and dissolution profiles.The second study compared the antisolvent (with organic solvent) and salting-out methods in their precipitation efficiency and product qualities. The phase behavior study showed that heavy precipitates composed of nanoparticles were the