Host cell proteins (HCPs) are process related impurities expressed by host cells during the production of biopharmaceuticals. The purification process eliminates the majority, but residual HCPs remain in the distributed products.
Regulatory authorities require that these impurities must be analyzed and purified to reduce the HCPs to an acceptance level. This is evaluated case by case and depend on a lot of factors, such as dose, frequency of drug administration, type of drug and severity of the disease.
The analytic is not simple as the HCP mixture contain a large number of protein species, unique to the host and not related to the biopharmaceutical.
A Single Injection LC-MS Analysis Scheme for Simultaneous Analysis of Biotherapeutics and Host-Cell Impurities via Online Digestion LC-MS/MS
Analysis of protein drug targets and impurities via LCMS involves time consuming offline protein digestion and separation. Automated protein digestion systems have addressed concerns of irreproducibility and improved laboratory efficiency by reducing human interaction with the sample. Although peptide mapping and Immuno-MS workflows are well established for on-line digestion, more complicated, orthogonal analyses have yet to be explored. Protein digestion of analyte proteins can be performed with or without affinity pulldown (depletion) of target proteins to enhance recovery of impurity proteins.