Lyophilization Optimization to Improve In Vitro Diagnostic Device Performance
This is the first in a multipart series on using lyophilized reagents or assays in diagnostic devices. In this post we will be discussing lyophilization process optimization.
Incorporating lyophilization into diagnostics has a number of benefits including simplifying logistics, improving shelf-life, and reducing costs (Ref1). Freeze-drying, also known as lyophilization, is a process in which water in the form of ice under low pressure is removed from a material by sublimation. Water is sublimated by the direct transition of water from solid (ice) to vapor, thus omitting the liquid state. This lyophilization process has many applications for the production of pharmaceuticals as well as freeze-dried foods that are often used for space exploration, emergency and survival applications, military rations, and camping (Ref2).
Lyophilization is a multi-step process that consists of freezing the product to a matrix of ice and other crystallizable excipients, most often under atmospheric pressure. Primary drying (also known as ice sublimation, main drying or initial drying) occurs most frequently under vacuum conditions, and is usually the longest, as well as the most complex and important step (Ref3). Secondary drying (also known as desorption, final drying, or residual moisture removal phase) of unfrozen water brings the product to the required final humidity (Ref3).
This lyophilization process optimization is particularly important for the manufacturing of diagnostic devices where the stability and shelf life of reagents are critical.
Lyophilization Process Optimization
Lyophilization process optimization is essential for enhancing the efficiency and quality of diagnostic devices when incorporating freeze dried reagents or assays. To obtain an effective lyophilization it is crucial to optimize both primary and secondary drying phases.
Here are the key aspects to lyophilization process optimization (Ref3 & Ref4):
- The freezing rate is critical for freeze-drying; the kinetics of ice nucleation and crystal development determines the physical condition, morphology, properties, and qualities of the lyophilized product.
- The primary drying segment typically attracts the most attention because it provides the best opportunity to significantly reduce overall cycle time. However, if not performed under the correct conditions, it can lead to significant product defects. About 95% of the water in the material is removed in this phase (Ref5).
- Secondary drying, during which an unfrozen fraction of water is removed from the product to achieve a target residual water content level, is usually a relatively straightforward part of freeze-drying. In this step a smaller amount of water needs to be removed, and the temperature used is higher, while the pressure is lower than in primary drying.
- Optimizing the formulations to ensure they are suitable for lyophilization, will improve the efficiency of freezing and drying phases. Using excipients that enhance the lyophilization process, such as cryoprotectants and lyoprotectants that improve stability and reduce cycle time, is standard practice.
For qPCR, some reagent providers or CDMOs provide master mix formulations with different excipients that are established to be successfully lyophilized. Users can purchase the various blends and test in liquid phase to identify the best performing master mix, then select that formulation for lyophilization. Argonaut provides this service, which can often de-risk lyophilization projects.
In the next blog post in this series “Lyophilization Optimization to Improve In Vitro Diagnostic Device Performance” we will cover Efficiency Improvements after lyophilization process optimization.
Argonaut Manufacturing Services provides a wide range of lyophilization manufacturing options from cakes, and LyoDose beads to LyoDots – the world’s smallest lyophilized spheres. For more information Contact Us.
References:
Ref 1: Argonaut Manufacturing Services. “How to Eliminate Hidden Cold Chain Costs- Lyophilizing Diagnostic Assays.” Retrieved from Argonaut Manufacturing Services. Accessed June 26, 2024
Ref2: Nowak D, Jakubczyk E. The Freeze-Drying of Foods-The Characteristic of the Process Course and the Effect of Its Parameters on the Physical Properties of Food Materials. Foods. 2020 Oct 18;9(10):1488
Ref3: Tchessalov S, Maglio V, Kazarin P, Alexeenko A, Bhatnagar B, Sahni E, Shalaev E. Practical Advice on Scientific Design of Freeze-Drying Process: 2023 Update. Pharm Res. 2023 Oct;40(10):2433-2455
Ref4: Kawasaki, Hidenori, Shimanouchi, Toshinori, Kimura, Yukitaka. Recent Development of Optimization of Lyophilization Process, Journal of Chemistry, 2019, 9502856, 14 pages, 2019
Ref5: Pauline M. Doran, in Bioprocess Engineering Principles (Second Edition), 2013
