Investigation of Drying Stresses on Proteins during Lyophilization: Differentiation between Primary and Secondary-Drying Stresses on Lactate Dehydrogenase Using a Humidity Controlled Mini Freeze-Dryer

This article describes the design, performance testing, and application of a controlled humidity mini-freeze-dryer in studying the physical stability of lactate dehydrogenase during lyophilization. Performance evaluation of the mini-freeze-dryer was conducted with tests, namely water sublimation, radiation heat exchange, lowest achievable temperature, and leak testing. Protein stability studies were conducted by comparing protein activity at various stages of lyophilization with the initial activity. The shelf and condenser temperature were stable at