Why 0.45 Micron Membrane Filters Are Used in Sterility Testing While 0.2 Micron Filters Are Used in Manufacturing
In pharmaceutical manufacturing and microbiological quality control, filtration plays a crucial role in ensuring product sterility and safety. However, many professionals often question why 0.45 µm membrane filters are used during sterility testing , whereas 0.2 µm (or 0.22 µm) filters are used in manufacturing filtration processes . Although both processes deal with microorganisms and sterility assurance, their purpose, mechanism, and validation criteria are completely different. This article explains in detail the scientific and regulatory reasons behind the use of these two filter pore sizes in different stages. 📘 Understanding the Purpose of Each Filtration Step To understand the difference, we must first recognize the intent of each process: Manufacturing Filtration (0.2 µm): This step is performed to remove microorganisms from the product during sterile manufacturing. It is a part of the production process that ensures the final product is sterile before it is fil...