Top-down production of drug nanocrystals: Nanosuspension stabilization, miniaturization and transformation into solid products

During the last 10–15 years, the formulation of drugs as nanocrystals has rapidly evolved into a mature drug delivery strategy, with currently five products on the market. The major characteristic of these systems is the rapid dissolution velocity, enabling bioavailability enhancement after oral administration. This mini-review focuses on recent advances with respect to three topics considering drug nanocrystals. The first topic is nanosuspension stabilization. A current literature status is provided and special attention is given to studies attempting to extend our physicochemical understanding of the underlying principles. The second part describes recent advances on miniaturization of nanosuspension production, to enable formulation screening during preclinical development. Finally, literature available on further nanosuspensions solidification is discussed, focussing on the maintenance of the preservation of the rapid dissolution properties of the nanocrystals after further downstream processing.