Combining Mathematical Modeling and Thermal Infrared Data in the Freezing of Pharmaceutical Liquid Formulations

Infrared-based (IR) thermal imaging data was combined here with mathematical modeling to describe the freezing process of a pharmaceutical formulation being lyophilized using two different loading configurations; (i) vials in direct contact shelf and (ii) suspended over it. In all experiments, nucleation event trigged at specific time instant vacuum induced surface (VISF) method. The IR given as input three models for used estimate resulting cake’s pore size (dp) distribution. dp values were then compared experimental obtained through SEM images coupled an image segmentation tool. supersaturation model showed best agreement between estimated values, while minor discrepancies shown by other models. Nonetheless, outcomes these last models, inputs primary drying phase, resulted satisfactory predictions product temperature moving front, resistance vapor flow, end point. It follows that combination thermocamera is promising tool in-line monitoring optimization freeze-drying cycle.