A highly sensitive and robust LC-MS platform for host cell protein characterization in biotherapeutics

Host cell proteins (HCPs) are a major class of process-related impurities that need to be closely monitored during the production of biotherapeutics. Mass spectrometry (MS) has emerged as a promising tool for HCP analysis due to its specificity for individual HCP's identification and quantitation. However, utilization of MS as a routine characterization tool is still limited due to the time-consuming procedures, non-standardized instrumentation and methodologies, and the limited sensitivity compared to the enzyme-linked immunosorbent assays (ELISA). In this study, we introduced a sensitive (limit of detection (LOD) at 1-2 ppm) and robust HCP profiling platform method with suitable precision and accuracy that can be readily adopted to antibodies and other biotherapeutic modalities without the need for HCP enrichment. The NIST mAb and multiple in-house antibodies were analyzed, and results were benchmarked with other reported studies. In addition, a targeted analysis method with optimized sample preparation for absolute quantitation of lipases was developed and qualified with an LOD of 0.6 ppm and precision of <15%, which can be further improved to an LOD of 5 ppb by using the nano-flow LC.