Theory and practice of supersaturatable formulations for poorly soluble drugs.

Candidate compounds with high activity do not always possess adequate physicochemical properties to be developed as commercial products. Notably, the development of candidates with poor aqueous solubility has been a great challenge in the past two decades. Formulations that offer supersaturated state during the dissolution process are considered effective for increasing the oral bioavailability of such candidates. Representative supersaturatable dosage forms include amorphous solid dispersions, nanocrystal formulations and self-(micro)emulsifying drug delivery systems. This review describes the characteristics of these formulations, with emphasis on the suitability of the candidates for each type of formulation, from a physicochemical viewpoint. Influence of developmental strategy on the formulation selection is also discussed. This review aims to provide guidance for selecting formulations for poorly soluble drugs based on both academic and practical backgrounds.