Dose-Response / Concentration-Response Analysis

Turn paired concentration vs response measurements into a potency (IC50/EC50), a Hill slope, an efficacy (Emax), and a quality judgment — and compare potency between compounds.

When to use this

• Enzyme inhibition / activation assays, cell viability, reporter assays, radioligand binding, agonist/antagonist pharmacology.
• You have a list of concentrations and the response at each, and want IC50/EC50 + Hill slope.
• You want to say "compound A is N-fold more potent than B."

The model is the 4-parameter logistic (4PL) / Hill sigmoidal: f(x) = Emin + (Emax − Emin) / (1 + (EC50/x)^n) — where n is the Hill slope.

Step 1 — Prepare the data (where results go wrong)