Pharmaceutical filter types explained

Sterility issues remain the leading cause of pharmaceutical recalls. In an increasingly competitive and regulated environment, filtration has never been more important in manufacturing processes, as reflected by a rapidly growing market valued at over USD 13 billion. Sterility failures threaten patient safety and expose manufacturers to regulatory, financial, and reputational risk. Adopting the right filtration strategy is key, but the wide range of filtration requirements and filter types can make this decision challenging.

At Atlas Copco, we help pharmaceutical teams navigate this complexity by providing expert guidance and high-quality process filtration solutions for all pharmaceutical use cases. This article provides a clear, practical overview of pharmaceutical filter types to support confident decision-making, reduce risk, and ensure reliable, compliant filtration performance at every stage of production.

Prefilters are used to remove larger particles that can interfere with downstream filtration steps. Depending on the process, they help eliminate cellular debris and aggregates and are broadly applied in API production, fermentation, and water treatment. By removing larger contaminants, effective prefilters protect downstream processes, reducing the need for frequent filter replacement, and improving overall process efficiency.

Polypropylene (PP) microfiber pleated filters are commonly used for prefiltration due to their broad chemical compatibility, making them suitable for a wide range of applications including removing large particles from ingredient solutions, stored solutions, and water. The pleated design increases filtration surface area, providing high dirt-holding capacity for demanding prefiltration applications, including solutions with high-particle loads.

These filters are designed to remove smaller contaminants and particles from solutions during pharmaceutical production. By selecting different pore sizes, membrane filters can exclude specific contaminants from downstream processes, such as microorganisms in fermentation media or aggregates and reaction by-products in API production.

• Polyethersulfone (PES) filters, such as our SME+ range, exhibit low extractables and low protein binding, and are well-suited for filtering non-aggressive aqueous solutions.

• Hydrophilic polyvinylidene fluoride (PVDF) filters, such as our SMV range, also exhibit low protein binding while offering greater mechanical strength, heat tolerance, and resistance to harsh conditions, making them suitable for high-temperature water filtration.

• Nylon filters (SMN range) offer broad chemical and solvent compatibility, making them suitable for aggressive solvents and high-pH samples. However, they should be avoided in applications where low biomolecule or protein retention is required.

   

These filters are available in both cartridge and capsule configurations.

Sterilizing-grade filters are used across pharmaceutical manufacturing to remove biological contaminants from final API solutions, formulation excipients, and fermentation nutrient feeds. A pore size of 0.22 µm is required to meet GMP and regulatory standards and is validated through the retention of Brevundimonas diminuta (107 CFU per cm2).

PES, PVDF, and nylon filters provide effective microorganism retention across a wide range of liquid types. Our SME+ (pharma-grade), SMV, and SMN filters are available with 0.22 µm pore sizes to ensure sterility and regulatory compliance across diverse applications.

Venting of storage and reaction tanks used in formulation and fermentation is essential for pressure equalization. However, sterile filtration is required to ensure that gas exchange does not introduce microbial or other contaminants. Prefiltration using PP or glass microfiber (GF) filters helps to capture larger particles, while polytetrafluoroethylene (PTFE) and sterilizing-grade GF filters can be used for sterilization.

• Sterilizing-grade PTFE membrane filters, such as our SMT-G range, offer broad chemical compatibility, making them suitable for sterilizing a wide range of gases, including in venting processes.

• GF filters, including our SFG-G range, provide high flow rates and low pressure drop characteristics, making them well-suited for sterile tank venting. They can also be used for filtration of compressed air and other gases.

Filtration is crucial for removing sources of contamination from steam and water used in pharmaceutical processes.

• Steam is commonly used for sterilization-in-place (SIP) of vessels and feed lines, but must itself be filtered to remove contaminants. Stainless steel filters tolerate high temperatures and are resistant to many corrosive gases and liquids, making them ideal for steam filtration.

   

• Water is a core component of pharmaceutical processes and final product formulations and therefore undergoes stringent treatment and filtration before use. This includes particulate removal (often using PP filters), activated carbon filtration, and sterilizing-grade filtration, often using PES (SME+) or PVDF (SMV), to ensure safe and compliant manufacturing.

Selecting the most appropriate filter at each stage of pharmaceutical production is essential to ensuring product quality, process efficiency, and regulatory compliance. Understanding the filtration requirements of each process and the strengths of different filter types helps manufacturers reduce risk, protect downstream processes, and achieve consistent, compliant performance across pharmaceutical production operations. 

Contact our experts today for guidance on selecting the right filtration solution for your pharmaceutical application.