Pharmaceutical filtration essentials: everything you need to know

Ensuring your filtration system performs consistently requires a systematic approach encompassing system design, validation, and integrity testing.

Right-sizing for optimal performance

Proper filter sizing prevents premature failure and ensures consistent performance throughout the filter's service life.

Undersized filters result in high flow rates that can reduce removal efficiency and cause rapid blocking. Oversized systems, on the other hand, create higher upfront costs due to larger housings and more expensive filter cartridges.

To ensure your filters are the right size for your process, you must understand:

• How much contamination your process generates
• What flow rates you need to maintain
• How much pressure drop you can tolerate

You should also factor in future production increases and upstream system modifications.

Generic sizing guidelines often fall short with pharmaceutical applications. Complex formulations, biologics, and high-viscosity products require careful calculations that account for your specific fluid properties and contamination characteristics.

Filter validation for effective contamination control

Filter validation proves your system consistently removes contaminants to the required level. It includes several key components:

• Bacterial retention testing using appropriate challenge organisms
• Compatibility testing to ensure filters don't interact adversely with your product
• Extractables testing to verify no harmful substances leach from the filter into your product

Your validation process must reflect your actual operating conditions. This provides the most accurate predictions as to how complex formulations perform under full-scale manufacturing conditions – something that isn’t possible with simplified fluids.

Integrity testing for guaranteed contaminant removal

Regular integrity testing ensures your filters can remove contaminants throughout their service life. It detects potential issues that could impact performance, including:

• Filter damage
• Seal failures
• Installation errors

Integrity testing protocols vary depending on your application and filter type. Bubble point tests work well for most membrane filters, while forward flow tests may be more appropriate for high-viscosity products, surfactant-containing formulations, or non-aqueous solvents.

The key is selecting tests that correlate with bacterial retention performance and can be performed routinely without damaging the filter.

Contained filtration systems protect operators from exposure to potent APIs during filter changeouts.

These systems encapsulate used filters in protective barriers, preventing contact with contaminated surfaces or airborne particles. For example, cytotoxic compounds or other materials that pose health risks.

Other design features that enhance operator safety include:

• Negative pressure systems that prevent release of airborne contaminants
• Glove box integration for handling highly potent compounds
• Automated systems that minimise direct operator interaction with contaminated equipment

Catalyst recovery presents additional safety challenges in API manufacturing.

Many pharmaceutical synthesis processes rely on rare, expensive, and environmentally harmful catalysts like palladium or platinum compounds. As such, recovering as much of these materials as possible is beneficial from both an environmental and economic standpoint.

However, spent catalysts often contain both the valuable metals and residual API compounds, creating a dual exposure risk during filtration and recovery operations. Contained filtration systems enable safe separation of these materials while protecting operators from contact with potent pharmaceutical residues.

Contained catalyst recovery system under the microscope

A pharmaceutical manufacturer needed to recover expensive palladium catalysts from its API production process while reducing operator exposure.

We implemented a modified SupaClean system utilising seven 20" SupaSpun II filters in a 30" length housing. This contained design eliminated operator exposure during catalyst recovery operations and simplified the handling and transportation process.

The system's enhanced capacity allowed retention of up to 3kg of concentrated catalyst slurry, enabling efficient recovery of valuable palladium without exposing operators.

Pharmaceutical filtration isn't one-size-fits-all. Pharmaceutical products span an enormous range – from simple glucose solutions to complex biologics with unusual viscosities and fouling characteristics. Each presents unique filtration challenges that require specific solutions.

Systems for easy-to-filter products

Pharmaceutical products based on simple formulations like glucose or saline – such as IV fluids and basic oral preparations – have relatively few particles and contaminants that need removing. This makes them ideal for single-layer membrane filters.

For these applications, single-layer membrane filters often provide excellent performance at reasonable cost.

SupaPore VP

The SupaPore VP series uses a pleated polyethersulfone (PES) membrane designed for aqueous pharmaceutical applications, with naturally hydrophilic properties and exceptionally low extractables making it ideal for reliable, high-quality filtrate.

SupaPore VPH

With a pleated, high surface area, our SupaPore VPH polyethersulphone (PES) membranes are designed for liquid processing applications and purified water systems. The naturally hydrophilic PES membrane eliminates the need for pre-wetting agents while maintaining consistent flow rates during extended filtration cycles.

SupaPore TTE

Our fluoropolymer SupaPore TTE filters use naturally hydrophobic PTFE membranes that are designed specifically for corrosive gases and liquid processing applications. Their high chemical resistance makes them suitable for aggressive pharmaceutical solvents and API solutions.

SupaPore TTG

Like the TTE series, our SupaPore TTG filters also use naturally hydrophobic PTFE membrane, but in a fully chemical-resistant construction. It offers excellent compatibility and consistently high-quality filtrate in any processes involving corrosive gases or aggressive liquids.

SupaPore TMB

For applications requiring high temperature resistance, our SupaPore TMB filters use a Polytetrafluoroethylene (PTFE) membrane. Featuring PPS membrane support/drainage layers, out TMB range resists oxidation in high temperature environments. They're specifically designed for heated vent housings and fermenter applications where standard materials would degrade.

Systems for hard-to-filter products

Complex pharmaceutical products – like protein solutions, cell culture media, or high-viscosity formulations – require more sophisticated filtration systems.

SupaPore VPBA

Our SupaPore VPBA filters are designed around a high flow, asymmetric hydrophilic PES membrane with a built-in pre-filter layer. This dual-layer construction improves dirt holding capacity, making it ideal for challenging or heavily loaded pharmaceutical solutions where bioburden control is critical.

Pharmaceutical filtration is subject to various regulations that span:

• Filtration system equipment design
• Validation requirements
• Manufacturing best practices

These regulations differ by region and product type. But wherever you operate, they serve the same purpose: to protect patient safety by ensuring filtration systems consistently remove contaminants and maintain sterility throughout their operational life.

In the pharmaceutical industry, the most important regulations are: