Best Practices and Guidelines (2022) for Scale-up and Technology Transfer in Freeze Drying Based on Case Studies. Part 2: Past Practices, Current Best Practices, and Recommendations.

Scale-up and transfer of lyophilization processes remain very challenging tasks considering the technical challenges and the high cost of the process itself. The challenges in scale-up and transfer were discussed in the first part of this paper and include vial breakage during freezing at commercial scale, cake resistance differences between scales, impact of differences in refrigeration capacities, and geometry on the performance of dryers. The second part of this work discusses successful and unsuccessful practices in scale-up and transfer based on the experience of the authors. Regulatory aspects of scale-up and transfer of lyophilization processes were also outlined including a topic on the equivalency of dryers. Based on an analysis of challenges and a summary of best practices, recommendations on scale-up and transfer of lyophilization processes are given including projections on future directions in this area of the freeze drying field. Recommendations on the choice of residual vacuum in the vials were also provided for a wide range of vial capacities.

Best Practices and Guidelines (2022) for Scale-Up and Tech Transfer in Freeze-Drying Based on Case Studies. Part 1: Challenges during Scale Up and Transfer.

The freeze-drying process scale-up and transfer remain a complicated and non-uniform practice. We summarized inefficient and good practices in these papers and provided some practical advice. It was demonstrated that using the same process set points/times in laboratory and commercial scale dryers may lead to loss of product quality (collapse or vial breakage). The emerging modeling approach demonstrated practical advantages. However, the upfront generation of some input parameters (vial heat transfer coefficient, minimum controllable pressure, and maximum sublimation rate) is essential for model utilization. While the primary drying step can be transferred with a high degree of confidence (e.g., using modeling), and secondary drying is usually fairly straightforward, predicting potential changes in product behavior during freezing remains challenging.

Lyophilizer Leak Rate Testing - An Industry Survey and Best Practice Recommendation.

The vacuum integrity of freeze dryers is critical for attaining adequate process control and maintaining confidence in sterility assurance which is key for the manufacture of sterile pharmaceutical products. Although discussions on the topic have been published, there is no industry standard established that is based on empirical data or that has a justifiable scientific rationale. This article provides a review of the scientific literature in the public domain and most importantly, a perspective from 14 Pharmaceutical companies on the leak rate specifications commonly used in industry. Using this information we recommend a best practice for the lyophilizer leak rate test which includes detailing necessary preparation activities following Steam-In-Place (SIP) sterilization, defining a period of stabilization to eliminate pressure and temperature fluctuations and details of the test conditions and the test period. We conclude that for routine manufacturing practice the operational leak rate should not exceed 20 µbar L/s and we provide additional guidance for large volume and older lyophilisation equipment.