We deliver scalable and robust GMP-compliant processes for viral vaccines.
The different upstream scales are matched with appropriately scaled downstream equipment for clarification, concentration, chromatography and filtration. For the purification of viruses, we offer clarification by depth filtration with a variety of different filters including filters that combine particle purification and impurity removal. Removal of nucleic acids is often required for viral products and can be achieved by techniques such as enzymatic digestion or fractional precipitation. Prior to purification, concentration and buffer exchange using tangential flow filtration can be performed using hollow fibers or flat screens. This is dependent on the physical properties of the target virus and the requirements of the final product.
Purification is normally achieved using several chromatography steps. The type of chromatography used is dependent on the virus properties. Commonly for purification, ion-exchange or hydrophobic interaction differences are exploited. For polishing and formulation, size-based group separation or tangential flow filtration can be used, be it hollow fibers or flat screens. Depending on the size of the viral product, a sterile filtration can be performed. For larger viruses for which this approach is not feasible, we have extensive experience in validated aseptic manufacturing processes. For analysis of the product, we offer a variety of product specific assays and assay development services, such as TCID50, PFA, FFA, ELISA, (q)PCR and HPLC-based methods.
We have extensive experience in developing virus purification processes from scratch, quickly transferring existing processes, and improving existing processes to increase purity or recovery. When developing a process from scratch, we can start with small-scale clarification development using scalable filters. If needed, a small scale UF/DF development for concentration and buffer exchange can be performed. This will be followed by chromatography development, starting with a selection of resins for binding and elution profiles, moving forward from 96-well plate screening to 1 mL spin traps and spin filters to intermediate and large-scale purification columns/filters/monoliths using ÄKTA™ explorer, ÄKTA™ pure and ÄKTA™ pilot, respectively. For viral vaccine purification, a two- to six-step process is usually required which results in 35-80% product recovery, thereby adhering to regulatory guidelines concerning purity.
In general terms, a viral vaccine purification process consists of clarification and concentration steps (sometimes preceded by cell lysis and DNA removal steps) followed by chromatography (charge, hydrophobic interaction, mixed mode, size exclusion, or affinity-based). Finally, the vaccine will be formulated by re-buffering and/or addition of components followed by a final membrane filtration step using a bioburden reduction or sterilizing grade filter. When delivering research batches for pre-clinical studies, we typically use centrifugation-based methods to deliver highly pure virus preparations.