Updates on the conversion of nanosuspensions to solid oral dosage forms

Pharmaceutical nanosuspensions, also called nanocrystals, are heterogeneous mainly aqueous dispersions of insoluble drug particles stabilised by surfactants and/or polymers. Nanosuspensions as liquid formulations suffer from instability. Solidification of nanosuspensions to solid dosage forms is a way to combine the advantages of nanocrystals with the advantages of the solid state. In this review, advances regarding stabilisation and production of nanosuspensions are briefly covered. Updates on the methods used to convert nanosuspensions to solid oral dosage forms (e.g., powder, granules, pellets, tablets, and films) are presented in depth. From these methods, spray drying and freeze drying are widely used. Granulation and hot-melt extrusion allow straightforward downstream processing, while printing exhibits the potential for dose personalisation. Focus is given on novel formulations (e.g., nano-cocrystals, nanocrystalline solid dispersions) which could further enhance the dissolution and bioavailability of poorly soluble drugs.