Partition Coefficient Calculator

Calculate log P, log D, and extraction efficiency for pharmaceutical and analytical applications

Example Molecules

Key Concepts

Log P: Partition coefficient = [organic] / [aqueous] for neutral species

Log D: Distribution coefficient at specific pH (accounts for ionization)

Lipinski's Rule: Drug-like molecules typically have -0.4 < logP < 5.6

Multiple Extractions: More efficient than single extraction with same total volume

Applications: Drug design, environmental fate, separation techniques

Understanding Partition Coefficients

The partition coefficient (P) measures how a substance distributes between two immiscible solvents at equilibrium, typically octanol and water. Log P is the base-10 logarithm of this ratio and is a fundamental parameter in medicinal chemistry, environmental science, and analytical chemistry.

The distribution coefficient (D) accounts for all species of the compound (ionized and unionized) at a specific pH, making it more relevant for predicting behavior in biological systems. Understanding both log P and log D is crucial for drug design, as they affect absorption, distribution, and excretion.