cGMP Chemical Network

Capture chromatography is a purification step that selectively binds the target biomolecule (e.g., antibody) to a resin, concentrating and partially purifying it from the bulk harvest. Key chemical categories are biological buffers, salts and acids/bases to control pH and ionic strength for binding and elution, biological reagents (chromatography resins), occasional low-percentage solvents or denaturants for specific elutions, and high-purity water for formulation and washes.

Viral inactivation reduces viral infectivity to improve product safety, typically applied to bulk intermediate streams prior to further purification. Common chemistries used for viral inactivation can include acids (low-pH treatments), solvents and surfactants/emulsifiers (solvent/detergent methods), biological buffers and salts to stabilize product during treatment, and high-purity water for dilution and neutralization steps.

Polishing chromatography removes trace impurities, aggregates, and charge variants to achieve final purity and product homogeneity after capture and viral clearance. This step uses biological buffers, salts and acids/bases for fine control of binding/elution, biological reagents (specialized resins), occasional denaturants or solvents for targeted impurity removal, and high-purity waters for washes and buffer prep.

Viral filtration (nanofiltration) is a size-exclusion step that physically removes viruses from the product stream using dedicated membrane cartridges under controlled flow conditions. Process chemistries associated with this step include biological buffers and salts to maintain product stability and ionic conditions, high-purity water for rinses and buffer prep, surfactants or antifoams to limit membrane fouling, and cleaning agents & disinfectants for filter integrity and reconditioning.

UF/DF concentrates the product and exchanges it into the desired formulation buffer by size-based retention and diafiltration, enabling buffer replacement and volume reduction. Typical chemicals are biological buffers and salts for final formulation, high-purity waters for diafiltration, acids/bases for pH adjustment, and occasionally surfactants or stabilizing excipients to preserve product stability.