In developing a sustained-release injectable suspension, the aqueous solubility of the drug substance is a critical material property affecting the drug release rate in tissues. For example, in the development of a sustained-release injectable suspension of paliperidone, the prodrug approach of adding palmitic acid to the drug substance reduced the solubility from 48.6 μg/mL of the free form crystal to ≤0.1 μg/mL, achieving suitable dissolution in tissues for a sustained-release injection. Therefore, a similar low solubility is desirable for the S-892216 drug substance. Table shows the solubility of S-892216 in various aqueous media. In all media, S-892216 showed extremely low solubility, from 0.61 to 1.08 μg/mL. These solubility data suggest that S-892216 exhibits potential for development into a sustained-release injectable suspension. 0.64 JP-2 fluid (pH 6.8) ** 0.61 *JP-1: 2.0 g sodium chloride was dissolved in 7.0 mL of hydrochloric acid and water to make 1000 mL to create a clear and colorless solution with pH 1.2. **JP-2: A mixture of phosphate buffer solution, pH 6.8 and water (1:1).