BioTechniques (Jun 2020)

A novel method for removing polyethyleneimine from biopharmaceutical samples: improving assay sensitivity of residual DNA qPCR

  • Shu-Min Zhang,
  • Matthew Roberts,
  • Marisa Jones,
  • Jacob Zeitler,
  • Greg Kilby,
  • Aston Liu,
  • John R White

DOI
https://doi.org/10.2144/btn-2020-0011
Journal volume & issue
Vol. 68, no. 6
pp. 353 – 358

Abstract

Read online

Polyethyleneimine (PEI) is a flocculent that is widely used in the downstream purification of monoclonal antibodies. It is an in-process residual that is carried through the drug purification process and strongly inhibits residual DNA quantitation by real-time quantitative PCR assay. Very high sample dilutions (e.g., 1:10,000) can overcome the interference of PEI, but at the cost of DNA assay sensitivity. Diluting samples poses a significant risk to the assay sensitivity needed to satisfy regulatory requirements on the quantitation of residual genomic DNA present per dose (i.e., 10 ng/dose). Removing PEI while retaining DNA, by the use of sodium dodecyl sulfate, heparin and/or sarkosyl can overcome the interference of PEI and allow a more accurate quantitation of residual DNA.

Keywords