Number of rotatable bonds
A count of the number of rotatable bonds. A large number of rotatable bonds (≥10) has been associated with poor oral bioavailability, particularly when associated with a high polar surface area (>140 Å2) (Veber et al. J. Med. Chem. (2002) 45 pp. 2615-2623).
This is defined by the following SMARTS pattern: [!$(*#*)!D1]-&!@[!$(*#*)!D1]