(643f) Prediction of Temperature and Moisture Content during Secondary Drying Process of Lyophilization Using One-Way Coupled Model

Freeze-drying is a widely used technique in the pharmaceutical industry for producing stable, long-lasting formulations of active pharmaceutical ingredients (APIs). The secondary drying process, which follows the primary drying phase, involves the removal of bound water from the dried product. In this process, accurate prediction of temperature and moisture content is crucial for ensuring product quality and stability. However, secondary drying is challenging to model due to the complex physics and large uncertainties in heat and mass transfer.

In this study, we developed a computational model to predict the temperature and moisture content during the secondary drying process of lyophilization. The model is based on solving one-way coupled equations for heat and bound water desorption. The Page model, a common empirical model for desorption kinetics, is compared against experimental data under varied operational conditions. We validated the model using experimental data obtained from lyophilization experiments on formulations containing various amounts of sucrose and BSA (bovine serum albumin). The results showed that the model accurately predicts the temperature and moisture content during the secondary drying process for shelf temperatures of 15^oC to 35^oC. We also comment on the molecular picture that is occurring during the desorption process.

Overall, this study demonstrates the feasibility of using a one-way coupled model to predict the temperature and moisture content during the secondary drying process. The model can be a valuable tool for process optimization and product quality control in the pharmaceutical industry.