Understanding Freeze Dry Microscopy

Lyophilization, or freeze drying, is a crucial process technology for many pharmaceutical and food products, and an essential part of extending product shelf life. Although lyophilization is fairly straightforward at the microscale, in bulk manufacturing it can be costly and complex. The goal of optimizing a lyophilization cycle is to reduce cycle time. This can be achieved by optimizing primary drying conditions by selecting appropriate chamber pressure and shelf temperature. To minimize cost and streamline the process, many laboratories utilize pre-lyophilization methods such as freeze dry microscopy (FDM).

Freeze dry microscopy focuses on the direct examination of freezing and freeze drying via a special microscope and thermal stage. It allows formulators to determine how their products will react in varying thermal conditions using small samples, instead of wasting large quantities of products by freezing them at less than optimal temperatures. Most importantly, it allows the scientist to determine actual collapse temperature of the product (Fig. 1), or the point at which it becomes unstable, or unusable. Every formulation has a definitive critical temperature: a point after which the formulation experiences processing defects and may be unusable. For this reason, knowing the critical temperature of a formulation before lyophilization takes place is essential. By using a microscope and thermal stage, researchers can determine optimal lyophilization conditions using less time and product.

sample collapse during freeze dry microscopy
Scientists utilize freeze dry microscopy to determine the actual collapse temperature of a product.

Members of the McCrone Group have a long history of supporting lyophilization laboratories and provide complete freeze dry microscope systems, as well as freeze drying training courses. We are also official members of the LyoHUB consortium at Purdue University. Please call or email today and learn more about these products and services.


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