Achieving Perfection - The ViruClear Virus Removal Lineup by Cobetter is Expanding

Achieving Perfection - The ViruClear Virus Removal Lineup by Cobetter is Expanding

Virus removal filtration is widely used in the biopharmaceutical industry for products such as antibodies, recombinant proteins, and other mouse-derived cell line expression products, as well as blood products and biochemical extracts. It is a key component of virus safety strategies during the production process.

It has been over three years since Cobetter launched its virus removal products in 2021 During this period, we have continuously achieved technological iteration to address more complex materials and improve filtration capacity. Currently, Cobetter's virus removal filter series includes three generations of Polyethersulfone (PES) material products and two new products of regenerated cellulose (RC). Soon, we will also introduce virus removal filters based on Polyvinylidene fluoride (PVDF) material.

In this article, we will explain and introduce several types of virus removal filters sold by Cobetter, so that you can better understand our related products and layout.

Cobetter Virus Removal Products

The ViruClear® Polyethersulfone (PES) material virus removal filter features high throughput and is suitable for most proteinaceous materials, with antibodies as the representative. The ViruClear® VF series products ensure robust retention of endogenous, exogenous viruses, and virus-like particles, allowing for large-volume protein material viral filtration operations within a controlled timeframe.

On the other hand, ViruClear® Regenerated Cellulose (RC) material virus removal filters exhibit excellent hydrophilicity and strong anti-clogging capabilities. They offer irreplaceable advantages in virus filtration for biological products such as blood factors.

Polyethersulfone (PES) Material Virus Removal Filter

Features of Cobetter Viruclear VF series

Upgraded welded version of the virus removal filtration syringe filter
The virus removal filtration syringe filter is primarily used in the process development stage of virus removal filtration in downstream purification of biopharmaceuticals. It is used for filter selection and process parameter exploration during small-scale trials, as well as for the validation and assessment of virus clearance capabilities. Cobetter's newly introduced Viruclear® VF WD (welding type) series syringe filters will completely replace the original polypropylene shell material virus removal filtration syringe filters. They will be used for laboratory-scale process development testing and the relevant evaluation of virus clearance validation.

Virus Removal Syringe Filters

The upgraded welded version of the syringe filter uses the same housing material as the pilot and production scale plastic housing filters, ensuring material consistency for product scale-up. At the same time, the upgraded syringe filters apply the same membrane welding and component welding processes as the larger components, ensuring more robust structural stability and virus removal.

Regenerated Cellulose (RC) Virus Filter

  • Made of regeneratedcellulose
  • Naturally hydrophilic.
  • Continuous asymmetric membrane cross-section

 Viruclear® RC (H) series of virus removal filters can withstand higher protein concentrations and are suitable for the virus removal of ultra-high protein concentrations (e.g. IVIG, SCIG, etc.).

Virus Removal Pre-filters


Nylon based pre-virus filtration

Structure: Nylon material, 0.1μm nominal microporous membrane, similar to dead-end sterilizing filters.

Principle: Pore retention + hydrophobic adsorption

Advantage: Adsorption is not much affected by pH and conductivity of the sample, suitable for hydrophobic materials with controllable E/L, small retention volume.


Based on depth-method pre-filtration (secondary depth filtration)

Structure: cellulose skeleton, diatomaceous earth filter aid, positively charged resin modification

Principle: Pore retention + charge, hydrophobic adsorption

Advantage: High flux, high loading capacity, depth filters are usually more effective in protection.

Integrated Virus Removal Systems

Integrated Virus Removal Systems
Virus Removal Consumables Fixture-1
Virus Removal Consumables Fixture-2

The virus removal filtration system consists of two main components: hardware holder and software systems. It is equipped with a variety of configurations and integrates installation points for viral pre-filters. Customers can personalize their setups according to their specific usage needs.

Case Study

Finally, through experimental cases, let's intuitively feel the performance of Cobetter's existing and under development virus removal filters in 4g/L bispecific neutral antibodies:

In the experiment, we used different material virus removal filters in series with deep-layer PDT and sterilizing-grade SMD pre-filters and conducted constant pressure filtration at 30 PSI.

From the attenuation of the flux curve, it can be seen that the Polyethersulfone (PES) material virus removal filter has a high initial flux but weak anti-clogging ability, leading to rapid flux decay. However, the Regenerated Cellulose (RC) and Polyvinylidene fluoride (PVDF) material virus removal filters, while having low initial flux, exhibit strong anti-clogging capabilities, maintaining relatively stable flux even when filtering highly contaminated materials.

Flux vs Time

Relevant Qualification

Currently, Cobetter has four viral filtration product series (including viral pre-filters) with Drug Master Files (DMFs), with the file numbers as shown in the table below. These DMFs have been formally submitted to the Food and Drug Administration (FDA) of the United States in eCTD format and have passed FDA administrative review. This signifies that in the future, users can directly reference the relevant information data of Cobetter's viral filtration product series when registering products according to their actual needs. The content of these DMFs can support New Drug Applications (NDAs), Investigational New Drug Applications (INDAs), etc.

According to the United States Code of Federal Regulations §314.420, Cobetter periodically maintains these DMFs and authorizes customers in both China and the United States to quickly reference the information of concern to regulatory authorities through the issuance of authorization letters, thereby assisting customers in successfully obtaining registrations.

DMF of Cobetter Virus Removal Products

In addition, Cobetter engineers have assisted over a hundred clients in completing more than 600 viral filtration process developments. This support has successfully facilitated clients in completing over a hundred batches of scale-up and production tasks. Moreover, Cobetter has conducted virus clearance validation work in over 50 instances through third-party execution of Investigational New Drug (IND) and Biologics License Application (BLA) studies.