In the pharmaceutical production process, the selection of microporous filtration membranes directly affects the quality and safety of the final products. From the perspectives of materials science and process verification, this article systematically analyzes the key elements for selection:

I. Chemical Compatibility Assessment

1. Advantages of PVDF material: Resistance to γ-ray sterilization (>25kGy), tolerance to a pH range of 1-12.
2. Applicable scenarios of PTFE: Strong acid and strong base systems (concentrated sulfuric acid/40% NaOH), high-temperature (<260°C) processes.
3. Characteristics of PES membrane: Low protein adsorption (<5μg/cm²), biological safety in line with USP Class VI.
4. Solvent resistance test: A 72-hour immersion experiment is required, and the volume change rate should be <3%.

II. Sterilization Efficiency Control

1. A pore size of 0.22μm can achieve a sterilization assurance level with LRV≥7.
2. The design of a double-layer gradient structure can increase the flux of feed liquids with high solid content (>500LMH).
3. Integrity test standards: Bubble point >3.5bar (water system)/diffusion flow <20mL/min.

III. Surface Property Matching

1. Hydrophilic modified membranes are suitable for water-based solutions (contact angle <50°).
2. Hydrophobic membranes used for gas filtration need to meet a contact angle >125°.
3. Surface charge regulation: Negatively charged membranes can reduce the DNA adsorption rate (>90%).

IV. Quality Compliance Requirements

1. It is necessary to provide the USP<87><88> bioreactivity test report.
2. Control of bacterial endotoxins <0.25EU/mL.
3. Extractables studies should include: TOC <500ppb, TSE/BSE statement.

It is recommended to establish a material screening matrix, comprehensively evaluate the characteristics of the feed liquid (viscosity, temperature, ionic strength), process parameters (pressure, flow rate), and compliance requirements, and conduct small-scale process verification when necessary.

1. Firstly, we must know whether the filter material has influence on the filter membrane. According the material choose the suitable filter membrane.
2. According to your filter material and process requirements choose the suitable membrane pore size.
3. Usually, there is no positive or negative side for membrane, but it's better to filter the material from the smooth side to the rough side.
4. Filtered solvents should be keep properly to avoid secondary pollution.
5. The waste membrane should be collected together and then process to avoid environmental pollution.

Nylon syringe filter is ideal for aqueous(non-acid) or organic sample prep and HPLC or dissolution sample analysis.
MCE syringe filter suitable for aqueous protein solutions.
PES syringe suitable for pre-filtration and filtration of buffers and culture media.
Hydrophobic PTFE syringe filter usually used in organic solvent with strong chemical causticity filtration. Hydrophilic PTFE syringe filter is versatile filter for aqueous and aggressive organic solvent-based solutions and especially ideal for HPLC operation.
PVDF syringe filter for filtration of non-aggressive aqueous and mild organic solutions, or were maximizing protein recovery is important.