Use Selectivity Index when you need to compute the ratio of toxic IC50 to therapeutic IC50 for a compound. Enter Therapeutic IC50 and Toxic IC50 using the definitions and units below so the result can be reproduced.

Therapeutic IC50

A finite measured or assumed value.

Toxic IC50

A finite measured or assumed value.

The published tool contract uses this rule: Compute the ratio of toxic IC50 to therapeutic IC50 for a compound.

Selectivity index

The calculated selectivity index.

A ratio or percentage can conceal the scale of its numerator and denominator and becomes sensitive to measurement error when the denominator is small. It is informational and cannot diagnose a condition, select treatment, or replace professional interpretation of the original measurements.

Retain the original Therapeutic IC50 and Toxic IC50 values and their units alongside the result. Selectivity Ratio is useful when you instead need to quantify drug selectivity as the off-target IC50 divided by the on-target IC50, where larger values indicate a more selective compound. Therapeutic Index provides another view by helping you compute the ratio of the toxic dose TD50 to the effective dose ED50.

• Selectivity Ratio

  Quantify drug selectivity as the off-target IC50 divided by the on-target IC50, where larger values indicate a more selective compound.

• Therapeutic Index

  Compute the ratio of the toxic dose TD50 to the effective dose ED50.

• Apoptotic Index

  Compute the apoptotic index as the ratio of apoptotic cells to mitotic cells.