Abstract
Improving process efficiency and product quality of freeze-dried formulations is relevant for wider use of unstable protein therapeutics and drug delivery systems. Post-freeze heat treatment and controlled nucleation are getting increasing attention as methods to obtain uniform large ice crystals that allow fast ice sublimation. We examined how these freezing procedures affect morphology and physical property of freeze-dried solids. X-Ray micro-computed tomography and scanning electron microscopy (SEM) indicated variations in the ice-trace structure of microporous solids depending on the freezing methods. The freezing methods also affected profile of myo-inositol crystal forms in the lyophilized solids. The results indicated relevance of physical characterization when applying these ice-size controlling methods in freeze-drying of pharmaceuticals.
