The following pharmacology definition has been taken from the Pharmacology and Experimental Therapeutics Department Glossary at Boston University School of Medicine.
The concentration of an agonist that produces 50% of the maximal possible effect of that agonist. Other percentage values (EC10, EC20, etc.) may be specified. Concentration is preferably expressed in molar units, but the mass concentration (g/l) may be used if the molecular weight of the substance is unknown.
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