Advanced screening assays to rapidly identify solubility-enhancing formulations: High-throughput, miniaturization and automation

Development of solubility-enhancing formulations for poorly water-soluble compounds always poses a challenge. Conventional formulation screening assays are potentially time-consuming and labor-intensive and, moreover, require a large amount of a compound; they are not ideal when compound availability and testing time are limited. In recent years, in-vitro screening assays that are rapid, inexpensive, minimally labor-intensive, and require only small quantities of a compound have become available. These advanced assays allow high-throughput automation, miniaturization, and parallel processing, thereby enabling scientists to rapidly identify solubility-enhancing formulations with milligram or sub-milligram quantities of an active pharmaceutical ingredient (API). This article reviews these assays for rapidly screening the aqueous solubility of lead compounds and the solubility-enhancing formulations with limited quantities of API.