Monitoring of the primary drying of a lyophilization process in vials

An innovative and modular system (LyoMonitor) for monitoring the primary drying of a lyophilization process in vials is illustrated: it integrates some commercial devices (pressure gauges, moisture sensor and mass spectrometer), an innovative balance and a manometric temperature measurement system based on an improved algorithm (DPE) to estimate sublimating interface temperature and position, product temperature profile, heat and mass transfer coefficients. A soft-sensor using a multipoint wireless thermometer can also estimate the previous parameters in a large number of vials. The performances of the previous devices for the determination of the end of the primary drying are compared. Finally, all these sensors can be used for control purposes and for the optimization of the process recipe; the use of DPE in a control loop will be shown as an exampl

Factors Affecting the Use of Impedance Spectroscopy in the Characterisation of the Freezing Stage of the Lyophilisation Process: the Impact of Liquid Fill Height in Relation to Electrode Geometry

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Characterization of the mass transfer of lyophilized products based on X-ray micro-computed tomography images

This paper proposes a systematic work process for the rapid determination of resistance to vapor flow given by the products being freeze-dried. This approach couples mathematical modeling and 3D nondestructive X-ray imaging to reconstruct the internal structure of lyophilized samples. Knowledge of the internal structure is fundamental to better understand the relationship between freezing and within-product heterogeneity as well as between freezing and the drying behavior of the product being lyophilized. The method was validated upon mannitol-based formulations using various freezing protocols. This stepwise approach was demonstrated to be helpful to lyophilization professionals for the control of within-product heterogeneity and for the optimization of the cycle