The pharmaceutical world is buzzing with changes following the recent update to the European Union Good Manufacturing Practice (EU GMP) Annex 1. Among various manufacturing processes, lyophilization plays a crucial role in preserving delicate biopharmaceuticals. As companies adapt to the new GMP guidelines, implementing aseptic process simulation (APS) in lyophilization has become both crucial and tricky.
This article dives into the complexities of APS for lyophilization, highlighting the challenges manufacturers face in meeting the updated regulations and providing recommendation for a better practice.
The challenges in APS for lyophilization
Designing an APS that accurately mirrors the complexities of lyophilization is a formidable task. According to paragraph 9.33 of Annex 1, “the APS should imitate as closely as possible the routine aseptic manufacturing process and include all the critical manufacturing steps”. Meanwhile, the process that may affect the viability or recovery of contaminants should be avoided.
A common lyophilization cycle consists of 3 steps: freezing, primary drying and secondary drying. During freezing, the product is cooled to at least -40°C to achieve complete solidification of the product. In primary drying, the drying chamber will be evacuated to a certain pressure, normally in range between 0.02 and 1 mbar. In the meantime, the shelf temperature is increased to provide the energy for sublimation which allows the solvent to be converted from solid into gaseous form directly. In the secondary drying, the shelf temperature is further increased, generally between 10°C to 40°C, so that the unfrozen solvent could be removed by desorption and diffusion. A common lyophilization cycle could take 2 to 7 days.
Due to the process condition of the lyophilization, the viability and recovery of contaminants could be affected by three main factors (Figure 1):
1.Temperature: when subjected to freezing temperatures, the media undergoes solidification, diminishing the viability and recovery of contaminants. Conversely, elevated temperatures during secondary drying may also adversely impact the viability and recovery of contaminants. It is noteworthy that the recommended storage temperature for nutrient media ranges from 2 to 25°C.
2.Pressure: maintaining the media temperature within the recommended range of 2 to 25°C is crucial. However, applying pressure within the range of 0.02 to 1 mbar can induce water boiling within the media, thereby affecting the recovery of contaminants.
3.Duration of the cycle: even with pressure and temperature kept within the desired range, an extended duration of a lyophilization cycle may jeopardize the viability and recovery of contaminants. This risk arises from the loss of water in the media through evaporation.
4.Condition for stoppering: the stoppering condition in a regular lyophilization process could negatively affect the viability and recovery of contaminants since the growth of most of the microbial in media requires oxygen while the vials are generally stoppered under vacuum or with backfilled inert gas.
Points to consider while developing an APS plan for lyophilization and recommendations
All key considerations in developing an APS plan are listed in paragraph 9.36. As discussed above, it is challenging to develop an APS plan that fully represents a typical lyophilization unit operation (Figure 2). During the operational phases of loading and unloading, chamber evacuation, and aeration, the APS settings deviate from those of a standard lyophilization process, as explained earlier.
1.Loading and unloading
1)Fully automatic loading
Since the half-stoppered vials are operated under Grade A clean room condition without human intervention, the risk of contamination is low.
Recommendation:
Only fully load the last shelf with media-filled container and the rest of the shelves with stoppered empty containers.
2)Fully manual loading
In contrast to fully automatic loading, fully manual loading introduces operator intervention, mak...
(All Rights Reserved)