In J. Med. Chem., 2000, 43 (20), pp 3714–3717, Ertl et al. propose the calculation of two polar surface area values, the first reports the PSA for Nitrogen and Oxygen atoms only, the second also includes Sulfur and Phosphorus in the calculation.

The default TPSA model in StarDrop is the first of these models, including only N and O. This was chosen based on feedback from users. However, we have also created a StarDrop model for the more general model for those who wish to use this definition.

Installing and using the model

Installation files
How to use the model

Save the model file (Right click on the link and select “Save Target As…”).
In StarDrop, either: Right click in the Models tab, select “Open” and browse to locate the model file.

Or, in File->Preferences->File Locations add the directory containing the model file. In the latter case, the model will appear in the list of available models whenever you start StarDrop.