Sterilizing Grade 0.2 Micron PTFE Membrane Filter Cartridge

SERENE Hydrophobic PTFE Sterilizing Grade 0.2um filter cartridges are highly retentive hydrophobic membrane designed for critical liquid and gas sterilization. Hydrophobic PTFE filter medium provides exceptionally high air flow rates at low differential pressures Naturally Hydrophobic Membrane also provides high assurance of filter integrity andlong life, during high temperature venting application and during repeated steaming. The PTFE membrane with specially designed high temperature construction provides excellent chemical compatibility and superior flow per unit area of steam-in-place and hot gas application.

Validated PTFE Membrane

All Cartridges are 100% integrity tested prior to release – Validation guide available on request. (Click here for Validation Guide)

SeraPure PTFE Filters provide microorganism retention based on following validation method

• Brevundimonas (Pseudomonas) diminutaliquid bacteria challenge :Complete retention of ≥ 107 organism/cm2 of Brevundimonas (Pseudomonas) diminuta in

   accordance with the current HIMA challenge methodology (ASTM F838-05)

• Aerosol Bacteriophage challenge (Gas) :Validated by aerosol bacterial (Staphylococcus aureus )and Viral (ø x174 Bacteriophage) challenge Test.


The hydrophobic membranes find application as air filters, generally as vent filters. These protect the contents of the tanks or other containers against contamination by the air that enters or leaves them as occasioned by the addition or withdrawal of their stored liquids. The concern is with the possibility of water finding lodgment in the membranes as a result of splashing, foaming, or even by the condensation of water vapor. Liquid water would possibly impede air passage, conceivably leading to tank collapse upon outpumping; moreover, water would encourage microbial growth. Contamination therewith is strongly to be avoided. The prescription against such an occurrence is to deny the presence of moisture. This can be done for hydrophilic filters using electrically heated or steam-jacketed filter housings. The temperature is raised above the dew point of the ambient air. Usually, steam at 1/3 bar (5 psi) pressure is enough. Unfortunately, the longtermpassage of air through such heated arrangements will cause the oxidative degradation of certain filter cartridge components, such as polypropylene, and may also oxidatively degrade the microporous membrane itself, depending upon its composition. Fluorinated polymers are relatively immune to oxidative alteration; PTFE extremely so, PVDF somewhat less so. That is why these polymers are so widely used in air filtration contexts. The greater hydrophobicity of PTFE offers substantial advantages.

Water Intrusion Test

The water intrusion test measures the decay rate of a pressure level imposed upon a hydrophobic filter enveloped by water. By means of an automated integrity tester, a particular decay level is identified as the point at which water enters the largest pores of the filter. The water intrusion test depends upon and measures the hydrophobicity of the filter. Only the experimentally demonstrated correlation of its values with the entrance of water into the hydrophobic pore structure establishes it as an integrity test. But the basic measurement of filter hydrophobicity is itself an inherent requirement in its pertinence to air filter reuse. Consider an integral air filter that contains hydrophilic accretions or deposits upon its surface. Their presence may encourage microbial growth and, ultimately, organism penetration. Solely ensuring air filter integrity, however essential, is not enough in air filter usage. The filter’s full hydrophobicity must also be assessed to ensure freedom from compromising hydrophilic impurities.

The adsorptive strength of a membrane is, thus, expressible in terms of its adsorption to a specific protein, both in terms of the quantity of protein it binds to the point of saturation, and in the extent available for adsorption beyond the point of contact.

Advantages and Disadvantages of Water Intrusion Testing

The water intrusion test offers several advantages. For example,

1. The test is highly sensitive because its test pressures are in the range of the WPP of 0.45 mm rated filters.

2. Contaminants such as solvent mixtures( IPA& Water) are avoided.

3. In addition to the integrity, the validated hydrophobicity is tested, i.e., any contaminants on the membrane can be discovered.

4. The test can be performed in place, after steam sterilization

5. Test times are greatly reduced, because contaminants do not have to be flushed off and in-place testing is not necessary.

The specifications defined by the filter manufacturers have to be observed to achieve reliable test results. In most cases the test is performed with automated test machines. This may be considered a disadvantage because of capital costs incurred. Nevertheless, automated test machines are usefully versatile and are also commonly used to perform other integrity tests such as the diffusive airflow and bubble point tests.

Long-Term Air Filter Applications

As previously stated, in the usual air filtration or vent filter applications, the filter is so little exhausted by the depositions it collects that its reuse is compelled for economic reasons; hence the need periodically to repeat its integrity verification before and after each individual use, ideally without removing it from its installation. The filter may remain integral, but if it collects, as it well may, deposits of hydrophilic matter, then as localized and limited as these may be, they can serve as loci for organism growth and penetration, defeating the very purpose intended by the use of a hydrophobic filter. If the intention of the integrity test in air filtration applications is solely to assess filter integrity, then the water intrusion test may, on occasion, mislead and be responsible for the discard of integral filters. If, however, the purpose of examining the filter is to gauge its suitability as a longer-term air filter, as in fermenter operations for example, then the water intrusion test is sovereign for the purpose because it simultaneously measures the integrity and the hydrophobicity of the subject filter. Both of these properties are required in a filter dedicated to longer-term air filtration applications.

Industrial Application

• Sterilizing GradeVent Filter for Tank Venting and Product.

• Compressed air filtration (Sterile Air)

• Bioreactor inlet and outlet gas filtration

• Sterile air filtration on blow, fill and seal machines

• Sterile venting of vessels and carboys

• Autoclave vacuum break line

• Sterile venting of lyophilisers

• Sterile process gas filtration

• Sterilize alcohol stream

Features & Benefits

• High Void Volumes

• High air flow at low pressure drops

• High steam cycle lifetimes and long service Benefits

• Highest Hydrophobicity of membrane

• Fully integrity testable by Water Intrusion, Bubble Point or Diffusion Flow test that ensures integrity and reliability.

• Validated by bacterial retention test (B. Diminuta) & Aerosol Bacteriophage challenge

• USFDA CFR Title 21 materials of construction, USP Class VI Biological Safety Test, Validation Guide and Drug Master File listing eases validation and regulatory


• Capsule filters are available in both gamma compatible and sterile formats whichEliminate cleaning and cleaning validation step associated with stainless steel

   housings for maximal ease-of-use.

Technical Specification


• Double layer hydrophobic PTFE

Support and Drainage Layers

• Polypropylene, oxidation resistant

Core, Cage, End Caps

• Polypropylene, oxidation resistant


• Polymeric, encapsulated in oxygen-resistant polypropylene

Sealing Technology

• Thermal Bonding without any Adhesives


• Sillicone,EPDM, Viton, Fluroelastomer, Buna M, Teflon Encapsulated Viton

Effective Filtration Area

• 7 ft² (0.65m²) per 10'' cartridge element

Available Micron Rating

• 0.1um, 0.2um (0.01um in a gas), 0.45um,0.65um,1.0um, 3.0um,5um and 0.01um

Regulatory Compliance

• The filters are constructed with polypropylene resins and filtration media in compliance with 21CFR Part 177 of the US Code of Federal Regulations and USP Class

   VI Biological Test for Plastic.

Nominal Dimension


• 5'' (13cm) , 10'' (25cm), 20''(50cm), 30'' (76cm) and 40'' ( 102cm)


• 2.75'' (70mm)

Operating Parameter

Maximum Differential Pressure (Forward Direction)

• 5.5 bar (80 psi) @ 25°C (77 °F) 1.7 bar (24.6 psi) @ 80 °C (176 °F)

Maximum Differential Pressure (Reverse Direction)

• 4.5 bar (65psi) @ 25 °C (77 °F)

Sterilization & Autoclaving

The filters can be sterilized by autoclaving for up to 100 cycles at 275°F/135°C. The filters can also be sterilized by steam-in-place procedure up to 100 cycles at 287.6°F/142°C for 30 minutes at less than 0.3 bar differential pressure. The filters can also sanitized by hot water or common chemicals that are compatible with filter components.


For 0.2um (0.003um in Gas)

Liquid: Complete retention of > 107 organisms/cm2 of Brevundimonasdiminuta in accordance with the current HIMA challenge methodology (ASTM F838-83). Gas: Validated by aerosol bacterial (Staphylococcus aureus and Viral (X174 Bacteriophage) challenge testing.

Integrity tested

All cartridges are 100% integrity tested—Validation Guide available upon request.

Product validation guide available on request. All SERENE cartridges are manufactured under strict control with batch number identification, giving full traceability on all components.