Caractérisation du mélange de poudres dans les procédés pharmaceutiques à l'aide de mesures d'effusivité

A novel process analytical technology (PAT) based on effusivity has been proposed recently to monitor the uniformity of powder blends resulting from pharmaceutical mixing processes. Effusivity is defined as [special characters omitted] and thus depends on the thermal conductivity (k), density (ρ) and heat capacity (C_p) of the blend. Effusivity being a measure of the thermal properties of the powders, it is possible therefore a priori to follow the homogeneity of a blend at different position in the blender (Mathews et al., 2002). The objective of this master's thesis is to gain insight into the accuracy, the sensitivity, and the limitations of effusivity as an indicator of blend uniformity.

The results obtained from these experiments reveal that the accuracy of effusivity as a process analytical tool for determining the blending times in powder blending processes depends on the blend characteristics and is a direct measurement of the blend density. This technology can be only employed when the variations of effusivity between the substances are high and when the blends are not diluted, which limits its utility for the determination of optimal blending time. (Abstract shortened by UMI.)