New SPR based assays for plasma protein titer determination

Abstract: Reliable analytical tools are important for time efficient and economical process development, production and batch release of pharmaceuticals. Therapeutics recovered from human plasma, called plasma protein products, involve a large pharmaceutical industry of plasma fractionation. In plasma fractionation of human immunoglobulin G (hIgG) and albumin (HSA) recommended analysis techniques are regulated by the European Pharmacopoeia and are including total protein concentration assays and zone electrophoresis for protein composition and purity. These techniques are robust, but more efficient techniques with higher resolution, specificity and less hands-on time are available. Surface plasmon resonance is an optical method to study biomolecular interactions label-free in real time. This technology was used in this master thesis to set up assays using Biacore systems for quantification of HSA and hIgG from all steps of chromatographic plasma fractionation as a tool for process development and in-process control. The analyses have simplified mass balance calculations to a high extent as they imply specific detection of the proteins compared with using total protein detection. The assays have a low hands-on time and are very simple to perform and the use of one master calibration curve during a full week decreases analysis time to a minimum. Quick, in-process control quantification of one sample is easily obtained within <10 minutes. For final QC of hIgG or for process development, an assay to quantify the distribution of the IgG subclasses (1-4) was set up on Biacore and showed significantly lower hands-on time compared with a commercial ELISA. All assays showed reliable quantification and identification performed in unattended runs with high precision, accuracy and sensitivity.