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Asymmetric Dialysis: Truly Unified and Simultaneous Single-Pass Concentration and Buffer Exchange
Ujwal Patil1, Michelle Chen1, Irina Ramos1
1Bioprocess Technologies and Engineering, Biopharmaceutical Development, AstraZeneca, Gaithersburg, Maryland, USA.
Biotechnology and Bioengineering
|May 13, 2026
Summary
Asymmetric dialysis is a new one-step continuous process combining ultrafiltration (UF) and diafiltration (DF) for biologics manufacturing. This sustainable technology reduces buffer consumption and integrates seamlessly into continuous bioprocessing workflows.
Area of Science:
- Bioprocessing Engineering
- Separation Science
- Biopharmaceutical Manufacturing
Background:
- Traditional ultrafiltration (UF) and diafiltration (DF) are often two-step batch processes hindering integration into continuous biomanufacturing.
- Existing UF/DF methods present challenges for efficient buffer exchange, desalting, and formulation of biologics.
Purpose of the Study:
- To introduce and evaluate asymmetric dialysis, a novel one-step continuous process for biopharmaceutical manufacturing.
- To demonstrate the capability of asymmetric dialysis to combine UF and DF functionalities for product concentration, buffer exchange, and salt removal.
Main Methods:
- Utilized a commercially available hollow fiber device with asymmetric flow between retentate inlet/outlet and dialysate.
- Exploited the interplay between feed and exchange buffer flow rates to optimize buffer consumption.
- Processed 7 kg of monoclonal antibody (mAb) from a 20 g/L feed concentration to a final concentration of 200 g/L over 5 days.
Main Results:
- Achieved high product concentrations (e.g., 200 g/L, 10x) at modest pressures (6-7 psi).
- Reduced buffer consumption by 75% compared to conventional batch UF/DF (25 L/kg mAb vs. 100 L/kg mAb).
- Demonstrated a daily productivity of 0.8 kg/m²-day.
Conclusions:
- Asymmetric dialysis is a simple, sustainable, and low-cost technology for bioprocessing.
- This novel one-step continuous process shows significant potential for integration into end-to-end continuous biomanufacturing.
- The technology offers substantial improvements in buffer efficiency and process integration compared to legacy batch UF/DF methods.
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