Host cell protein detection via surfactant-assisted acid precipitation

The detailed characterization of host cell proteins (HCPs) is essential for ensuring the safety and efficacy of biopharmaceutical products. Liquid chromatography mass spectrometry (LC/MS) provides enhanced specificity and comprehensive analysis for characterizing residual HCPs. However, high-abundance drug substances can interfere with HCP detection, necessitating sophisticated sample preparation strategies to selectively deplete these substances. Traditional methods like immunoprecipitation and chromatography-based fractionation, while effective, are often time-consuming and labor-intensive. To address these limitations, a novel surfactant-assisted acid precipitation (SAAP) technique has been developed. This method uses ionic amphipathic surfactants to disrupt the equilibrium between monoclonal antibodies (mAbs) and HCPs, facilitating selective mAb depletion through acid-induced precipitation. The SAAP method is a straightforward, quick, two-step process optimized for approximately 99.9 % mAb depletion, enhancing HCP detection via LC/MS. It allows for selective depletion of hydrophobic proteins, enriching more hydrophilic HCP subsets, and can be integrated with other workflows like size exclusion chromatography (SEC) to improve sensitivity and coverage. Despite the risk of losing certain targeted HCPs, SAAP enables the identification of unique HCP subsets not detectable by other techniques, demonstrating its potential as a robust tool in biotherapeutic development.