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Choosing the Right Buffer Filter

White and blue Millipore Express® filters filters of different formats and sizes. Blue filters are gamma compatible, white capsules are autoclave-compatible.  Cartridge filter elements with no filter housing are shown.

Biopharma production requires large volumes of multiple buffers for different processing steps. Choosing a buffer filter can be complex: the filtration membrane and format you select will depend on your process step, level of bioburden control you need, buffer volume, and buffer characteristics. Whether you need a buffer filter for process development or for a critical formulation buffer, we have it covered.  Our Millipore Express® and Milligard® PES, non-PFAS, buffer filters all deliver high flow and capacity at a reasonable cost and are offered with bacterial retention specifications that deliver the right level of bioburden control for your specific process needs.

Sterilizing Buffer Filters

For sterile filtration of non-plugging buffers we recommend Millipore Express® SHF (Sterile, High Flux) filters or Millipore Express® PHF (Process protection, high flux) filters. All Millipore Express® capsule and cartridge filters contain a 0.2 µm PES sterilizing membrane, that provides high permeability, easy wetting and integrity testing and broad chemical compatibility.

For more plugging buffers, Millipore Express® SHC (Sterile, High Capacity) filters are a better option. These filters contain an integrated 0.5 µm polyethersulfone (PES) membrane prefilter that protects the 0.2 µm PES sterilizing membrane, maximizing filter capacity.

  • Millipore Express® SHF and Millipore Express® SHC filters should be used for critical process buffers steps that require sterility assurance.
  • Millipore Express® PHF filters are a cost-effective, sterile buffer filtration option for buffers used in less critical steps, that may not need sterility assurance.

Bioburden Reduction Buffer Filters

Milligard® PES  filters can be used as bioburden reduction buffer filters. These filters offer fast flow, high throughput, easy wetting and integrity testing and broad chemical compatibility and are a cost-effective buffer filtration option.

Two pore sizes are available, each with different bioburden reduction specifications:

  • Milligard® PES 1.2/0.2 µm nominal: typically ≥ 6 log Brevundimonas diminuta removal based on ASTM F838 methodology
  • Milligard® PES 1.2/0.45 µm: typically ≥ 6 log Serratia marcescens removal based on ASTM D3863 and F838 methodology

Formats From Bench to Production Scales

All our buffer filters feature:

  • OptiScale® formats for efficient screening and scaling, and cartridge and capsule formats for larger volume processing.
  • Gamma-compatible formats, that can be integrated into Mobius® single-use assemblies.

Approximate filtration areas of capsule and cartridge filters. Refer to product specifications for complete information.

Quality Standards and Documentation

All Millipore Express® and Milligard® PES filters are designed, developed, and manufactured in accordance with a Quality Management System approved by an accredited registering body to an ISO 9001 Quality Systems Standard, and are supported by a certificate of quality.

Millipore Express® SHF, Millipore Express® SHC and Milligard® PES filters are supported by the Emprove® Program which provides three types of dossiers to support different stages of development and manufacturing operations such as qualification, risk assessment, and process optimization. The dossiers consolidate comprehensive product-specific testing data, quality statements, and regulatory information in a readily available format so you can move forward with confidence.