The molecule of interest can either be excreted or can accumulate within the cells. When this happens, the cells must first be disrupted, degradation prevented, and impurities separated from the molecule of interest.

Centrifugation and microfiltration are optimal methods to separate the molecule from the cell, and only the supernatant can be collected for further purification.

Real-time measurement of pressure, flow, particle accumulation, size distribution, pH, or turbidity of cell both feeding into and out of filters can provide feedback control to minimize process disruption.

Viruses are inactivated and rendered nonpathogenic. In-line spectroscopy, turbidity, pH monitoring, and control guarantee consistency throughout the process.

The target product is isolated and concentrated by chromatography.

While antibodies are captured by affinity chromatography using resins with protein A, protein G, or other selectively engineered methods, oligonucleotides and nonprotein molecules are often captured by ion exchange chromatography, polysaccharides, and complex glycan by hydrophobic interaction or IMAC chromatography.

Common measurements include pressure, flow, pH, Fourier transform infrared (FTIR) spectroscopy, UV-Vis, and conductivity before the chromatography column to monitor variable feed inputs and provide information on the column quality and performances. 

With the purification step, the residual impurities (such as proteins, nucleic acids, endotoxins, etc.) are removed through a succession of unit operations—clarification, extraction, chromatography, tangential flow filtration—while the product is retained as much as possible and is further concentrated using tangential flow filtration (TFF) via ultra/diafiltration (UF/DF).

The goal is to increase purity without losing yield. Monitoring flow, pressure, conductivity, pH, turbidity and yield weight during the buffer preparation and purification ensures reliability throughout the process.

Viruses are inactivated and rendered nonpathogenic to ensure biotherapeutics' safety by altering the solution environment (lowering the pH or adding solvents/detergents). In-line spectroscopy, turbidity, pH and ORP monitoring, and control guarantee consistency throughout the process.

With polishing, the final purity is achieved.

Scientists use size exclusion chromatography and tangential flow filtration to remove trace impurities—viral particles, bacterial pathogens, and endotoxins—and exchange the purification buffer with formulation one.

While FTIR spectroscopy can help quantify and speciate fraction components during polishing chromatography, monitoring pressure, flow, conductivity, pH, and turbidity throughout all the polishing unit ops—including the buffer preparation, pledge for product safety, and quality.