Enter the concentration of organic and aqueous partition into the calculator to determine the partition coefficient and LogP.

Log P Formula

The following formulas are used to calculate a partition coefficient and logP. 

P = [O] / [A]
  • Where P is the partition coefficent
  • O is the concentration of organic partition
  • A is the concentration of aqueous partition
Log(P) = log10 (Partition Coefficient)

Partition Coefficient Definition

The partition coefficient is a crucial concept used to determine the distribution of a substance between two immiscible phases, usually a liquid and a solid or a liquid and a gas. It quantifies the extent to which a compound partitions or distributes itself between these phases.

More specifically, the partition coefficient, often denoted as P, is the ratio of the concentration of a solute in one phase to its concentration in another phase at equilibrium.

It represents the equilibrium distribution of the solute between the two phases and is expressed as the ratio of the solute’s concentrations in each phase.

The significance of the partition coefficient lies in its ability to predict and understand the behavior of a substance in different environments. It helps in determining the solubility and transport of various chemicals, drugs, and pollutants in different systems.

By knowing the partition coefficient, scientists can estimate how a substance will distribute itself between different compartments, such as blood and tissues, or within different organs. This information is vital for drug development, toxicology studies, and environmental risk assessments.

What is LogP?

LogP is a value that indicates whether a substance will be absorbed by plants, animals, humans, or other living tissue. In other words, how easily it can be carried away and disseminated by water.

Example Problem

How to calculate LogP?

  1. First, determine the concentration of the organic partition.

    For this example, the concentration of the organic portion is 65%. For this example, percentages are used for simplification of the calculation.

  2. Next, determine the concentration of the aqueous partition.

    In this case, the aqueous portion is 30%.

  3. Next, determine the partition coefficient.

    Divide the result from step 1 by the result in step 2 to get the partition coefficient.
    65/30 = 2.1666.

  4. Finally, calculate the LogP value.

    Log(P) = log10 (Partiion Coefficient)
    Log(P) = log10 (2.1666)
    Log(P) = .335