Tangential flow ultrafiltration/diafiltration (UF/DF) is the last major step in the active constituent process.
During this step, your plasmid DNA can be concentrated up to 15 mg/mL with very low genomic content. Great care is taken to preserve the integrity of your plasmid. It is added to the UF/DF system using a controlled transmembrane pressure that allows the plasmid to recirculate through the system in a high velocity, yet low shear manner.
This technique effectively removes impurities and molecule fragments to leave behind only your plasmid DNA in its desired concentration.
Completing the bulk plasmid production process is aseptic filtration of your plasmid DNA into sterile containers.
In this step, the concentration of the plasmid fractions obtained from the UF/DF is determined and adjustments are made to ensure concentration is at the specified value.
Aseptic techniques are utilized in a cleanroom environment to filter your plasmid into a bulk container. Samples are then taken for Quality Control testing and the final bulk plasmid is stored at a standard -75 to -85ºC for preservation until the final bottles are filled.