What are Lipinski Rule of 5 criteria?

Lipinski Ro5: MW <500, logP <5, HBD (hydrogen bond donors) <5, HBA (hydrogen bond acceptors) <10. Compounds violating ≥2 rules: poor oral absorption predicted. PSA <140 Å2 and rotatable bonds <10 (Veber criteria) additionally predict oral bioavailability. Biologic drugs and natural products are exempt.

Which QSAR models predict aquatic toxicity?

ECOSAR (EPA): predicts fish, Daphnia, algae toxicity from logP and structure class using linear free energy relationships (LFERs). QSAR for baseline narcosis: log(1/LC50) = 0.87 x logP - 1.19 for fathead minnow. Electronic and steric descriptors improve predictions for reactive compounds beyond narcosis.

What are 2D vs 3D QSAR descriptors?

2D (constitution, topology): MW, logP, fragment counts, topological indices (Wiener, Randic). 3D (geometry, pharmacophore): surface area, volume, E-state, CoMFA fields. 2D QSARs: faster, no conformation required. 3D QSARs: more accurate for receptor binding but require active conformation assumptions.

QSAR Molecular Descriptor and Activity Prediction

Constant	Symbol	Value	Units
Speed of light	c	2.99792458×10⁸	m/s
Planck's constant	h	6.62607015×10⁻³‴	J·s
Boltzmann constant	kʙ	1.380649×10⁻²³	J/K
Avogadro's number	Nₐ	6.02214076×10²³	mol⁻¹
Gravitational constant	G	6.6743×10⁻¹¹	N·m²/kg²
Gas constant	R	8.31446	J/(mol·K)
Elementary charge	e	1.602176634×10⁻¹⁹	C
Electron mass	mₑ	9.1093837015×10⁻³¹	kg
Proton mass	mₚ	1.67262192369×10⁻²⁷	kg
Fine-structure constant	α	7.2973525693×10⁻³	dimensionless

Constant

Symbol

Value

Speed of light

2.99792458×10⁸

Planck's constant

6.62607015×10⁻³‴

Boltzmann constant

kʙ

1.380649×10⁻²³

Avogadro's number

Nₐ

6.02214076×10²³

Gravitational constant

6.6743×10⁻¹¹

Gas constant

8.31446

Elementary charge

1.602176634×10⁻¹⁹

Electron mass

mₑ

9.1093837015×10⁻³¹

Proton mass

mₚ

1.67262192369×10⁻²⁷

Fine-structure constant

7.2973525693×10⁻³

How It Works

Apply quantitative structure-activity relationships (QSAR) using molecular descriptors (logP, MW, PSA, HBD, HBA, rotatable bonds) to predict biological activity, aquatic toxicity, or pharmacokinetic properties. Evaluate Lipinski Ro5 compliance and Veber drug-likeness criteria

Each component has a specific meaning:

Molecular descriptors (logP — The molecular descriptors (logp recorded for the scenario being assessed.
MW — The mw recorded for the scenario being assessed.
PSA — The psa recorded for the scenario being assessed.
HBD — The hbd recorded for the scenario being assessed.
HBA — The hba recorded for the scenario being assessed.
Rotatable bonds) — The rotatable bonds) recorded for the scenario being assessed.

Note: Interpret the qsar descriptor activity result against the thresholds and context described above.

How to Use

Enter the molecular descriptors (logP, MW, PSA, HBD, HBA, rotatable bonds) for the scenario you are assessing. Apply quantitative structure-activity relationships (QSAR) using molecular descriptors (logP, MW, PSA, HBD, HBA, rotatable bonds) to predict biological activity, aquatic toxicity, or pharmacokinetic properties. Evaluate Lipinski Ro5 compliance and Veber drug-likeness criteria. Use the qsar descriptor activity result to inform your calculation.

QSAR Molecular Descriptor and Activity Prediction

How It Works

How to Use

Related Calculators

Frequently Asked Questions