Descriptors, Properties and Rules Computed in FAF-Drugs4

(available in the results.csv file)
Descriptor Denomination Minimum Parameter Maximum Parameter
Molecular Weight MW inf_mw sup_mw
Molecular weight or molar mass
logP logP inf_logp sup_logp
The logarithm of the partition coefficient between n-octanol and water, characterizing lipophilicity.
XLOGP3 and OpenBabel methods were benchmarked on a set of 1300 molecules with experimental logP values from US National Cancer Institute,
showing that XLOGP3 (r2=0.94) give a better prediction accuracy.
Lipinski RO5 stands on CLOGP values, but Mannhold et al. benchmarked several models and showed that XLOGP3 and CLOGP methods give similar results [46]
logD logD - -
The logD represents the logP of compounds at physiological pH (7.4)
logSw logSw - -
The logSw represents the logarithm of compounds water solubility computed by the ESOL method [45]
topological Polar Surface Area tPSA inf_psa sup_psa
summation of tabulated surface contributions of polar fragments (i.e. atoms regarding also their bonding pattern)
Hydrogen Bond Donnors HBD inf_hbd sup_hbd
sum of all OHs and NHs (according to Lipinski RO5 definition)
Hydrogen Bond Acceptors HBA inf_hba sup_hba
sum of all O and N (according to Lipinski RO5 definition)
Hydrogen Bond
Donnors and Acceptors
HBonds inf_hba sup_hba
sum of Hydrogen Bond Donnors and Acceptors
Note: only involved in the "respirtory" filter according to Ritchie et al. [25]
Number of SSSR n_SystemRing inf_nc sup_nc
The Smallest Set of Smallest Rings (SSSR) is the smallest ring building blocks necessary to form otherring systems (e.g. 3 for a compound involving 3 phenyl)
Size of the Biggest
System Ring
MaxSizeSystemRing - max_ring
Number of atoms involved in the biggest system ring (e.g. 12 for 2 fused 6 membered-ring)
Number of Rotatable Bonds RotatableBonds inf_nbb sup_nbb
Number of any single non-ring bond, bounded to nonterminal heavy (i.e., non-hydrogen) atom.
Amide C-N bonds are not considered because of their high rotational energy barrier, as decribed by Veber et al. [41] .
Number of Rigid Bonds RigidBonds inf_nrb sup_nrb
Number of non-flexible bonds, in opposite to rotatable bonds (e.g. double and triple bonds, bonds involved in ring systems and additionnaly amide bonds)
Number of Charged Groups NumCharges inf_cf sup_cf
Number of Charged Groups
(e.g. 1 for a compound with a carboxylic acid group)
Compound Total Charge TotalCharge inf_sc sup_sc
Formal total charge of the compound.
(e.g. -1 for a compound with a carboxylic acid group)
Number of Carbon Atoms n_carbon inf_c sup_c
Number of carbon atom
Number of Heteroatoms n_hetero inf_h sup_h
Number of non carbon atoms (hydrogens are not included)
Number of Heavy Atoms inf_hva sup_hva
Number of non hydrogens atoms
het/carbon atoms ratio ratioH_C inf_r sup_r
The ratio between the number of non carbon atoms and the number of carbon atoms.
Number of Rule-of-5 Violations n_LipinskiViolations - max_lipinski
Rule of thumb according to Lipinski et al [13] stating on that 4 properties:
MW ≤ 500; H-Bonds Donors ≤ 5 ; H-Bonds Acceptors ≤ 10 ; logP ≤ 5
If two properties are out of range, a poor absorption or permeability is possible, one is acceptable.
Solubility Solubility - -
Water Solubility mg/l estimated by ESOL method [45]
Solubility Forecast Index Solubility Forecast Index - -
Water Solubility estimated by Hill et al method [77]
Veber Rule VeberRule - -
Bad or Good oral biovailability rule, according to Veber et al [41] stating on:
(rotatable bonds ≤10) and (tPSA ≤ 140 Å or H-Bonds Donors+H-Bonds Acceptors ≤ 12)
Egan Rule EganRule - -
Bad or Good oral biovailability rule, according to Egan et al. [40] stating on:
( 0 ≥ tPSA ≤ 132 ) and ( -1 ≥ logP ≤ 6)
Oral PhysChem Score TrafficLights - -
An Oral PhysChem Score extensively used at Bayer according to Lobell et al. [38]
GSK 4/400 GSK 4/400 - -
Rule which relates to compounds with a logP less than 4 and a MW less than 400 Da may have a more favourable ADMET profile [26]
Pfizer 3/75 Pfizer 3/75 - -
Rule which relates to compounds with a high log P (>3) and low TPSA (<75) are approximately 2.5 times more likely to be toxic as to be clean [54]
Fsp3 Fsp3 - -
According to Lovering et al. [39], Fsp3 (carbon bond saturation) is defined as the number of sp3 hybridized carbons / total carbon count. This descriptor could correlates with melting point and solubility.
Number of Stereocenters StereoCenters - -
According to Lovering et al. [39], the presence of stereo centers (also, number of chiral centers), is a descriptor of complexity which also increases from discovery through clinical trials, to drugs
Compound Final Status State - -
Compound state after all rules applied (i.e. Accepted, Intermediate or Rejected)
Note: logP value is by default computed by using the XLOGP3 program [5], enhanced by employing an in-house library of experimental logP values from the PHYSPROP database [38].
One can alternatively use the embedded OpenBabel method by activating the dedicated option.