Emerging and Enabling Technologies in Membrane Separations

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1 Emerging and Enabling Technologies in Membrane Separations Andrew L. Zydney Distinguished Professor of Chemical Engineering The Pennsylvania State University 2 nd International Symposium on Continuous Manufacturing of Pharmaceuticals Cambridge, MA September 27, 2016

2 Continuous BioProcess Media (excipients) Cell Recycle Clarification Primary Capture Polishing Bioreactor Host Cell Proteins (Water) Impurities (e.g., DNA)

3 Membranes in Bioprocessing Media Sterile Filtration of All Inputs (excipients) Cell Recycle Clarification Primary Capture Polishing Bioreactor Host Cell Proteins (Water) Impurities (e.g., DNA)

4 Membranes in Bioprocessing Media Bioburden Control Particle / Aggregate Removal (excipients) Cell Recycle Clarification Primary Capture Polishing Bioreactor Host Cell Proteins (Water) Impurities (e.g., DNA)

5 Membranes in Bioprocessing Media Cell Recycle Clarification using Microfiltration (TFF of ATF) Clarification Primary Capture Polishing (excipients) Bioreactor Host Cell Proteins (Water) Impurities (e.g., DNA)

6 Membranes in Bioprocessing Media Cell Recycle Clarification Primary Capture Polishing (excipients) Membrane Chromatography High Performance TFF Bioreactor Host Cell Proteins (Water) Impurities (e.g., DNA)

7 Membranes in Bioprocessing Media Virus Filtration (excipients) Cell Recycle Clarification Primary Capture Polishing Bioreactor Host Cell Proteins (Water) Impurities (e.g., DNA)

8 Membranes in Bioprocessing Media (excipients) Cell Recycle Clarification Ultrafiltration Diafiltration (UFDF) Primary Capture Polishing Bioreactor Host Cell Proteins (Water) Impurities (e.g., DNA)

9 Membranes in Bioprocessing Media Sterile Fill (excipients) Cell Recycle Clarification Primary Capture Polishing Bioreactor Host Cell Proteins (Water) Impurities (e.g., DNA)

10 Membranes in Bioprocessing Media Membrane-Assisted Precipitation Countercurrent Tangential Chromatography (excipients) Cell Recycle Clarification Primary Capture Polishing Bioreactor Host Cell Proteins (Water) Impurities (e.g., DNA)

11 Normal Flow Filtration Continuous Processing Likely to be achieved by switching between modules arranged in parallel configuration Challenge need for high capacity Minimize membrane area, reduce switching frequency (sterility) Current Approach Combination of pre-filter and sieving membrane Depth filter media with multiple components

12 Membrane Chromatography Continuous processing Flow through-mode (impurity removal) done using parallel arrangement (single-use) Bind-and-elute configuration more challenging ( multi-column format?) New ligands / membranes under development Higher binding capacity (less frequent replacement) More robust binding (e.g., salt-tolerant ligands) Multi-modal ligands with enhanced selectivity

13 Tangential Flow Filtration Challenge new process configuration needed Current modules and process configurations were designed for batch processing Need to eliminate feed recycle currently used in most TFF applications (e.g., UFDF) Current Approaches Alternating Tangential Flow Filtration (ATF) Single Pass Tangential Flow Filtration (SPTFF) Countercurrent staging

14 ATF Alternating Tangential Filtration Withdrawal from Bioreactor Return to Bioreactor Pressure Cycle Exhaust Cycle Filtrate Filtrate Air Air

15 ATF Alternating Tangential Filtration Flow reversal Unclogs blocked fibers, disrupts boundary layer Very low flux operation Minimizes cell deposition Backfiltration in situ membrane cleaning Membrane fouling remains problematic Need for new membranes specifically developed for continuous clarification with perfusion Opportunities for new high performance modules

16 Single Pass TFF Required conversion (concentration) achieved in single pass through module Specially-designed (e.g., Pall Inline Concentrator) Long modules (e.g., modules in series) Single-use systems (replace as needed) Membrane fouling remains problematic Need for new membranes / modules specifically developed for long-term operation

17 Process Configuration - Staged Diafiltration Diafiltered Product Feed UF Module DF Stage 1 DF Stage 2 Diafiltration - Continuous, single-pass, operation - High solute removal due to staging + high conversion

18 Countercurrent Staged Diafiltration For N = 1, a flow ratio of α = 19 corresponds to a 20- fold reduction in solute concentration Same flow ratio provides: R = 380 for N = 2 R = 7,200 for N = 3 R = 138,000 for N = 4

19 Membrane-Assisted Processes Membrane systems can be used for fluid management in continuous versions of classical downstream processes Chromatography flowing resin instead of packed column Precipitation washing and re-dissolution of precipitate to enhance yield and purification Countercurrent staging of membrane modules can significantly enhance performance

20 Continuous Countercurrent Tangential Chromatography (CCTC) Chromatographic resin (beads) flows as a slurry through a series of static mixers and hollow fiber membrane modules All operations (binding, washing, elution, stripping) performed directly on the slurry Hollow fiber membrane allows separation and collection of fluid phase Static mixers provide residence time + uniformity Countercurrent staging reduces buffer and resin requirements while increasing yield

21 Continuous Precipitation Precipitation Wash Stage Dissolution Precipitant Wash Dissolution

22 Membranes - Summary Membrane systems will play a critical role in development of continuous processes Sterility barrier, virus clearance, clarification, purification, formulation Challenges: Membranes, modules, and process configurations were all developed for batch operations Efforts to develop continuous membrane processes lag those for chromatographic systems Membrane fouling remains major challenge