Solvent/detergent (SD) treatment is a robust industrial method to inactivate enveloped viruses and to effectively reduce potential viral contaminations. While continuous processing and process economy are extensively discussed among the biopharmaceutical community, the vast majority of industrial bioprocesses are still batch-oriented comprising many unit operations that are not fully automated. Based on the patent from Hasslacher et al., an initial mass capture step for the purification of recombinant ADAMTS13 was established that features both – impurity and virus clearance – by utilizing SD treatment directly on a chromatographic column. A novel combination of wash and incubation steps ensures uniform saturation of the column with SD reagents as well as sufficient contact time to effectively inactivate
enveloped viruses. Crucial process performance parameters including product yield, specific activity and impurity clearance were compared to the standard protocol of the capture step and results indicated at least equivalent process performance. Depletion of SD reagents after on-column inactivation led to a >4 log10 reduction compareable to the standard protocol. The behavior of SD reagents was investigated by moment analysis indicating interaction
of tri-n-butylphosphate and partial interaction of Triton X-100 with the chromatographic resin. Investigations of the virus clearance capacity of on-column SD treatment with the representative model virus X-MuLV demonstrated that infectious virus was cleared to below the detection limit of the TCID50 assay. In comparison to control runs without SD reagents, developed on-column treatment demonstrated an effective virus inactivation. Data showed that the virus did bind onto the anion-exchange resin. Further experiments, where virus was spiked into a protein-free matrix demonstrated a similar binding effect, suggesting direct interaction of the virus with the chromatographic resin as opposed to binding through bound proteins. The on-column virus inactivation has the potential to streamline purification processes. It reduces the total number of unit operations and manufacturing space for large vessels, enabling a cost-efficient and more automated viral inactivation than the traditional batch-oriented SD treatment.