Views: 251 Author: LOONG FILTRATION Publish Time: 2025-11-18 Origin: Site
Microfiltration technology plays a pivotal role in the pharmaceutical industry, widely applied in sterile gas preparation, Water for Injection (WFI) production, the preparation of drug substances and drug products, and the clarification of traditional Chinese medicine extracts. Proper selection of the filter pore size rating is a core step in ensuring drug quality and safety.
As a benchmark enterprise in China's ternary precursor sector, the customer plays a key role in the core link of the new energy lithium battery industry chain and adheres to strict product quality standards. However, in the solid-liquid separation process of ternary precursor production, the original filtration configuration of "PP needle-punched felt filter bag + PP pleated filter element" gradually exposed two core bottlenecks, seriously affecting production continuity and cost control
Application Scenario | Performance Metric | Recommended Pore Size Rating |
Clarification and Visible Particle Removal | Intuitive Transparency | 3–5 μm Filter |
Macromolecule/Colloid/Particle Removal | Yeast and Mold Removal | 1.2–0.65 μm Filter |
Bioburden (Bacteria) Reduction | Pyrogen Reduction | 0.45 μm Filter |
Bacterial Retention (Sterilization) | Asepsis (Sterility) | 0.22 μm Sterilizing Grade Filter |
Mycoplasma Retention / Small Organic Molecule Removal | Asepsis, Mycoplasma-free | 0.1 μm Mycoplasma Removal Grade Filter |
Experimental studies have confirmed that 0.22μm pore size micro-porous membrane filters can be used for bacterial retention to achieve sterilization. Both hydrophilic and hydrophobic micro-porous membranes are used for sterilization. The bacterial retention performance of 0.22μm sterilizing grade filters is independent of filtration pressure and the amount of organic substances. There is a certain correlation between the filter's physical integrity test value (such as the bubble point test value), bacterial retention, and the filter type.
In general, sterilizing grade filters possess strong retention capabilities, even ensuring absolute sterility downstream when operated above the manufacturer's recommended effective operating pressure. For instance, a 0.22μm sterilizing grade filter can retain up to10⁷CFU/cm² of Brevundimonas diminuta at a pressure of 0.2MPa.
Pre-treatment: Use activated carbon for decolorization and pyrogen removal, followed by a titanium rod or stainless steel mesh to intercept activated carbon particles.
Pre-filtration: Select a depth filter membrane with high dirt-holding capacity, such as a polypropylene (PP) or glass fiber membrane, with a filtration rating of 0.5–20μm.
Terminal Sterilization: Employ a high-performance polyethersulfone (PES) membrane with a pore size rating of 0.22μm to ensure drug liquid safety.
Activated Carbon Cartridge
Metal Sintered Filter
Multi-layer Gradient Polypropylene (PP) Membrane Filter Cartridge
Asymmetric Polyethersulfone (PES) Sterilizing Grade Filter Cartridge
Biologics Filtration
Pre-filtration: A glass fiber membrane with a filtration rating of 0.45–5μm is recommended due to its large flow rate, good biocompatibility, and low protein adsorption. Additionally, mixed cellulose ester (MCE) membranes are also suitable for pre-filtration of biologics due to their good biocompatibility, low protein adsorption, and low cost.
Terminal Sterilization: Use a low-protein adsorption PES membrane, or a dual-layer structure to increase dirt-holding capacity. For high-value biologics, a hydrophilic polyvinylidene fluoride (PVDF) membrane is recommended to further minimize protein adsorption.
Glass Fiber Membrane Filter Cartridge
Mixed Cellulose Ester (MCE) Membrane Filter Cartridge
Low Protein Adsorption Polyethersulfone (PES) Membrane Filter Cartridge
Lowest Protein Adsorption Hydrophilic Polyvinylidene Fluoride (PVDF) Membrane Filter Cartridge
Gas Filtration
Pre-filtration: Options include PP membrane, glass fiber membrane, stainless steel sintered mesh, or titanium rods (suitable for high temperature and high pressure), with a filtration rating of approximately 2–100μm
Sterilization Filtration: Gas sterilization first requires ensuring filtration effectiveness, guaranteeing 100% bacterial removal under both dry and moist conditions. Sterilizing grade filters have high precision, which can lead to increased resistance and energy consumption. Therefore, sterilizing filter cartridges needs to be reasonably configured. The commonly used membrane is hydrophobic Polytetrafluoroethylene (PTFE), with pore size ratings of .1μm and 0.22μm.
PP Membrane or Glass Fiber Membrane Filter Cartridge
Stainless Steel Sintered Mesh or Titanium Rods
Hydrophobic Polytetrafluoroethylene (PTFE) Membrane Filter Cartridge
GB/T 34244-2017 Technical requirements for filter elements for liquid sterilization
GB/T 36118-2018 Polytetrafluoroethylene microporous membrane pleated filter elements for gas sterilization
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