Toward QbD Process Understanding on DNA Vaccine Purification Using Design of Experiment

This paper investigates a systematic approach to understanding the purification process of DNA vaccines, specifically focusing on a hydrophobic interaction chromatography (HIC) step. The authors utilized Design of Experiment (DoE) with a central composite face-centered (CCF) approach to evaluate the impact of process parameters such as sample application flow rates and salt concentrations during washing and elution on critical quality attributes (CQA) like supercoiled DNA content and performance attributes (PA) like step yield. The study used pVax1/lacZ as a model DNA vaccine. Through 14 experiments and four additional runs at center points, regression predictive models were established, and simulations were conducted in 10,000 runs to determine tolerance intervals for CQAs and PAs. The findings demonstrate that this Quality by Design (QbD) approach can be effectively applied to optimize DNA vaccine purification processes, ensuring high purity and yield of the supercoiled isoform, which is crucial for vaccine efficacy. The methodology provides a robust framework for process understanding and control, which can be scaled up for larger production.

This paper investigates a systematic approach to understanding the purification process of DNA vaccines, specifically focusing on a hydrophobic interaction chromatography (HIC) step. The authors utilized Design of Experiment (DoE) with a central composite face-centered (CCF) approach to evaluate the impact of process parameters such as sample application flow rates and salt concentrations during washing and elution on critical quality attributes (CQA) like supercoiled DNA content and performance attributes (PA) like step yield. The study used pVax1/lacZ as a model DNA vaccine. Through 14 experiments and four additional runs at center points, regression predictive models were established, and simulations were conducted in 10,000 runs to determine tolerance intervals for CQAs and PAs. The findings demonstrate that this Quality by Design (QbD) approach can be effectively applied to optimize DNA vaccine purification processes, ensuring high purity and yield of the supercoiled isoform, which is crucial for vaccine efficacy. The methodology provides a robust framework for process understanding and control, which can be scaled up for larger production. Research Background and Significance The development and purification of DNA vaccines have emerged as critical frontiers in biopharmaceutical innovation, particularly given their potential for rapid response to emerging infectious diseases. DNA vaccines rely on plasmid DNA (pDNA), where the supercoiled isoform (SC) is the most biologically active and efficacious form, making its purity a critical quality attribute (CQA). Ensuring high purity and yield of SC plasmid DNA during downstream purification steps is essential for vaccine potency and regulatory compliance. This study by Hocharoen et al. addresses the growing need for a s