Advanced Freeze-Drying Modeling: Validation of a Sorption-Sublimation Model

Area of Science:

• Pharmaceutical Sciences
• Chemical Engineering
• Process Modeling

Background:

• Freeze-drying (lyophilization) is critical for product stability, but its complex heat and mass transfer dynamics pose optimization challenges.
• Traditional experimental methods for freeze-drying are resource-intensive and time-consuming.
• Accurate modeling is essential for understanding and optimizing lyophilization processes.

Purpose of the Study:

• To develop and validate a novel sorption-sublimation model for vial freeze-drying.
• To accurately predict product temperature and residual moisture during lyophilization.
• To improve upon existing modeling approaches for enhanced process efficiency and product quality.

Main Methods:

• A new sorption-sublimation model was developed using two new coordinates to map the moving boundary to a fixed domain.
• The model incorporates accurate descriptions of heat and mass transfer during dynamic drying stages.
• Simulation results were validated against experimental data and compared with the pseudostationary approach.

Main Results:

• The developed model demonstrated good agreement with experimental data, achieving deviations as low as 3.9%.
• This represents a significant improvement over the pseudostationary approach, which showed up to 42.2% deviation for edge vials.
• Residual moisture prediction showed similar error margins (7%) between experiment and simulation, with an 8% deviation from experimental values.

Conclusions:

• The validated model provides accurate and precise predictions for vial freeze-drying processes.
• It offers valuable insights for optimizing process parameters, enhancing product quality, and reducing development costs.
• The model serves as a robust tool for predicting lyophilization behavior in research and industrial settings.