05.07.2018 | LOGFILE Feature 28/2018

An excerpt from the GMP Series download Aseptic Processing of Sterile Medicinal Products

Executing Sterile Filtration

6 min. reading time | by Ruven Brandes


When performing sterile filtration of a solution, it is recommended that a SOP describing all required components of the equipment and accessories should be used in order to ensure that no steps are omitted.

All openings on equipment and accessories must be covered with sterilisation paper and secured with indicator strips. All components must be labelled with the batch number and drug product designation. The pore width and type of all filters must also be specified.

All components and devices (see Figure 4) have been cleaned and sterilised in accordance with the SOP.


The assembly process must be performed from the cleaner grade B to grade C.

All accessory components removed from sterilisation devices (for example, pass-through autoclave from cleanliness grade D/C to cleanliness grade B) must be checked to ensure the integrity of the sterilisation seals and packaging, and transported together to the place of use.

When working under laminar flow (LF), the following must always be noted:

  • The necessary interventions under LF are only permitted following disinfection of gloved hands.
  • The work should always be performed from underneath the open surfaces exposed to the airflow.
  • Whenever possible, use tweezers or other utensils (use small tools and instruments so as not to disturb the LF).
  • The filter assembly is performed as described in Figure 5.
  • The sterile connection from the filter to the storage container has now been established. The container for the sterile filtered solution is either sterilised together with an assembled air filter, or this filter must be mounted, as described for the sterile filter in Figure 5.

In CIP/SIP facilities, cleaning and sterilisation of equipment is easier than described in Figure 12.E-5 but still requires assembly steps for which the same level of care must be observed.


The sterile filtration process performs as described in Figure 6.

The use of nitrogen as a compressed gas creates a nitrogen atmosphere in the storage container as a result of the nitrogen dissolved in the solution. In case of longer holding times of the sterile solution, it should be actively overlaid with nitrogen. Holding times before filling must be validated and limited.

The sterile filter is subsequently removed from the storage container (see Figure 7).

Ruven Brandes


Ruven Brandes
Energy and Sanitation Inspector and Head of Technology and Compliance Support at WDT
E-Mail: brandes@wdt.de

Aseptic Processing of Sterile Medicinal Products

In this GMP Series PDF Download you will find answers to the following questions:

  • What requirements are rooms and personnel expected to meet for aseptic processing?
  • How is the bioburden reduced by means of sterile filtration?
  • How is sterile filtration validated?
  • How is the aseptic filling method proved?
  • What interventions should take place in the processes?
  • What must be borne in mind with respect to personnel qualification in the context of media fills?
  • What measures must be taken when acceptance criteria are exceeded in the context of media fills?

> More information and order