Understanding the Options

Serum

Clarification and Prefiltration

• Remove lipids, colloidal and particulate contaminants
• Operate consistently at high differential pressures and flow rates
• Extend the lifetime of final filters
• Must be able to withstand multiple steam-in-place or hot water sanitization cycles
• Run efficiently to ensure process economics

Recommended Filter	Filter Characteristics
Triple-layer Millistak+ HC Filters (Grade A1HC or B1HC) Disc Filters Pod Filters	Triple-layer configuration includes a membrane bottom layer to enhance filter loading capacity and retention Higher filtrate quality allows smaller size requirements for downstream sterilizing-grade filtration step Unique design enables the compression of multiple process steps into one, lowering overall filtration costs The selection of Grade A1HC or B1HC depends on the fluid particle size distribution and should be based on small-scale testing.
Clarigard Filters (0.5 µm, 1.0 µm or 3.0 µm) Cartridge Filters Opticap Capsule Filters	Polypropylene prefilter for robust particle and colloid removal Validated for multiple sanitization and SIP cycles Higher filtrate quality allows smaller size requirements for downstream sterilizing-grade filtration step Non-fiber releasing structure preserves product purity Available in a wide-range of pore sizes to accommodate the needs of each user. Choice should be made based on small-scale testing.
Double-layer Milligard Filters (Grade SS, 0.5 µm + 0.2 µm, or Grade SC, 1.2 µm + 0.5 µm) Cartridge Filters Opticap Capsule Filters Optiscale Capsule Filters	Double-layer pleated configuration of mixed esters of cellulose membranes remove particles and colloids High porosity membranes operate at high flow rates and low pressure drops Non-fiber releasing structure preserves product purity 100% integrity tested to ensure quality Robust construction validated to withstand multiple SIP or hot water sanitization cycles Available in a variety of pore sizes to accommodate the needs of each user. Grade SS is commonly used to protect downstream 0.22 µm sterilizing-grade filters. Grade SC is better suited to protect 0.45 µm membrane filters. Choice should be made based on small-scale testing.
Polysep II Filters (Grade W3, 1 µm + 0.2 µm) Cartridge Filters Opticap Capsule Filters Optiscale Capsule Filters	Depth filter consisting of a borosilicate glass layer and a layer of mixed esters of cellulose membranes Robust prefilter for concentrated solutions across a full range of flow rates High particle-loading capacity and retention Able to withstand multiple SIP or hot water sanitization cycles Non-fiber releasing

Final Filtration

• Reduce bacteria and mycoplasma to ensure long term storage and stability
• Eliminate the risk of adventitious infectious agents
• Operate consistently at high differential pressures and flow rates
• Must be able to withstand multiple steam-in-place or hot water sanitization cycles
• Run efficiently to ensure process economics

Recommended Filter	Filter Characteristics
Durapore CBR 0.1 µm Filters	Low protein-binding PVDF membrane Retentive membrane reduces bioburden Low extractables and non-fiber releasing PVDF chemistry preserve product purity and yield High flow rate at low pressure drop for reliable economic processing 100% integrity testing ensures quality Validated for multiple SIP and hot water sanitization cycles Although 0.1 µm is typical for this application, Durapore CBR 0.2 µm filters are also available. Choice should be based on small-scale screening.
Durapore 0.1 µm Filters Cartridge Filters Optiseal Cartridge Filters Opticap Capsule Filters Optiseal Capsule Fitlers	Sterilizing-grade PVDF membrane will assure bioburden and mycoplasma clearance 100% Integrity testing and thousands of existing applications assure proven performance Integrity testable on-site Although 0.1 µm is typical for this application, Durapore filters are available in several pore sizes and in single-layer or multi-layer configurations to accommodate the needs of each user, the degree of protection required for the downstream process and the plugging characteristics of the fluid. Choice should be based on small-scale testing.
Millipore Express SHR 0.1 µm Filters (with or without prefilter layer) Cartridge Filters Opticap Capsules Optiscale Capsules	Designed to remove high levels of mycoplasma and bacteria over a range of moderately plugging to highly fouling streams Asymmetric pore structure delivers extremely high flow rates at low pressure drop Sterilizing-grade PES membrane provides broad chemical compatibility across a wide pH range (1–14) 100% integrity tested to ensure quality Robust construction validated for multiple SIP cycles Can be integrity tested on-site Available in single-layer 0.1 µm or double-layer 0.1 µm with prefilter layer 0.1 µm configurations. The degree of protection required for the downstream process and the plugging characteristics of the fluid will guide this selection. Choice should be based on small-scale testing.