Aqueous solubility is one of the key factors that determine the oral bioavailability of a drug. Being related to ADME-Tox descriptors, it is one of the main physicochemical properties to be optimized in drug discovery.
For more information, see Solubility Predictor.
The solubility of a compound is the concentration in equilibrium with the solid phase that is dissolved into the solution. Instead of the concentration its natural logarithm, logS, is used for convenience in the literature. In JChem for Excel two functions are related to this property:
There are many types of solubility defined in scientific literature, most of the methods developed for in-silico prediction calculates intrinsic solubility for a given compound, which is the solubility of the un-ionized form in the absence of acids or bases.
In case only a rough estimation is needed, the plugin can give a solubility category as a qualitative measure. These categories are as follows:
Low: Solubility is < 0.01 mg/ml.
Moderate: Solubility is between 0.01 and 0.06 mg/ml.
High: Solubility is > 0.06 mg/ml.