In an era of increasing need to develop drug candidates with tightening timelines and resources, the pharmaceutical industry is facing an ever more challenging pipeline with >50% poorly water soluble chemical entities. Solid dispersion formulations, an emerging field addressing some of these issues, enable the rapid development of poorly water soluble compounds by placing the drug in a physically stabilized amorphous state capable of increasing its apparent solubility.

A solid dispersion necessitates the inclusion of a drug molecule and supersaturation-enhancing polymer in a stable, homogeneous solid mixture produced by melt extrusion, solvent evaporation, or analogous processes. Predictive thermodynamic models, such as Flory-Huggins, aid in the selection of a suitable polymer or mixture of polymers having favorable interactions with the drug candidate. Inclusion of surfactants often enhances the compatibility of hydrophobic drug with hydrophilic polymer, providing improved bioavailability over the binary system alone. By exploring the molecular level interactions between drug and polymer candidates, we can understand the influence of structure on in vivo performance.