Factors Affecting Freeze Drying Product Resistance



In a freeze drying process, mass transfer and product temperature are dependent upon the resistance of the product matrix to water vapour flow. Product resistance is influenced by numerous factors such as nature of the product, solute concentration and freezing properties, and was found to differ between formulations and process conditions used.In this study product resistance as a function of dry layer thickness for various sucrose solutions was characterised using the SMART™ Freeze Dryer Technology. SMART is a new PAT concept for the optimization of a lyophilisation process even during the first laboratory experiment. Using the data derived by SMART it is possible to determine optimum vial sizes, and fill depths / volumes to help rapidly optimise not only the freeze drying process but also the best vial sizes and fill volumes to use. S. Schneid, H. Gieseler



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