Developing oral solutions is a popular solubility enhancement approach. In the development of oral solutions, determining the solubility of the drug in various solvents is an important stage. As a result of screening various solvents, we found that PEG 400 exhibited the highest solubility at 15-20 mg/mL (Table ). Therefore, PEG 400 oral solution of S-892216 was proposed for ADME human studies.