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EC50: Difference between revisions
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'''Half maximal effective concentration''' ('''EC<sub>50</sub>''') is a measure of the concentration of a drug, antibody or toxicant which induces a biological response halfway between the baseline and maximum after a specified exposure time. More simply, EC<sub>50</sub> can be defined as the ''concentration required to obtain a 50% [...] effect''{{pmid|23265506}} and may be also written as [A]<sub>50</sub>.{{pmid|14657418}} It is commonly used as a measure of a drug's potency, although the use of EC<sub>50</sub> is preferred over that of 'potency', which has been criticised for its vagueness.{{pmid|14657418}} EC<sub>50</sub> is a measure of concentration, expressed in molar units (M), where 1 M is equivalent to 1 mol/L. | '''Half maximal effective concentration''' ('''EC<sub>50</sub>''') is a measure of the concentration of a drug, antibody or toxicant which induces a biological response halfway between the baseline and maximum after a specified exposure time. More simply, EC<sub>50</sub> can be defined as the ''concentration required to obtain a 50% [...] effect''{{pmid|23265506}} and may be also written as [A]<sub>50</sub>.{{pmid|14657418}} It is commonly used as a measure of a drug's potency, although the use of EC<sub>50</sub> is preferred over that of 'potency', which has been criticised for its vagueness.{{pmid|14657418}} EC<sub>50</sub> is a measure of concentration, expressed in molar units (M), where 1 M is equivalent to 1 mol/L. | ||
The EC<sub>50</sub> of a ''graded'' dose response curve therefore represents the concentration of a compound where 50% of its maximal effect is observed. | The EC<sub>50</sub> of a ''graded'' dose response curve therefore represents the concentration of a compound where 50% of its maximal effect is observed. | ||
The EC<sub>50</sub> of a ''quantal'' dose response curve represents the concentration of a compound where 50% of the population exhibit a response, | The EC<sub>50</sub> of a ''quantal'' dose response curve represents the concentration of a compound where 50% of the population exhibit a response, after a specified exposure duration. | ||
For clarification, a graded dose response curve shows the graded effect of the drug (y axis) over the dose of the drug (x axis) in one or an average of subjects. A quantal dose response curve shows the percentage of subjects where a response is noted in an all-or-none manner (y axis) over the dose of the drug (x axis). | For clarification, a graded dose response curve shows the graded effect of the drug (y axis) over the dose of the drug (x axis) in one or an average of subjects. A quantal dose response curve shows the percentage of subjects where a response is noted in an all-or-none manner (y axis) over the dose of the drug (x axis). | ||
For competition binding assays and functional antagonist assays [[IC50|IC<sub>50</sub>]] is the most common summary measure of the dose-response curve. For agonist/stimulator assays the most common summary measure is the EC<sub>50</sub>. | For competition binding assays and functional antagonist assays [[IC50|IC<sub>50</sub>]] is the most common summary measure of the dose-response curve. For agonist/stimulator assays the most common summary measure is the EC<sub>50</sub>. | ||
The EC<sub>50</sub> is also related to [[IC50|IC<sub>50</sub>]] which is a measure of a compound's inhibition (50% inhibition). | The EC<sub>50</sub> is also related to [[IC50|IC<sub>50</sub>]] which is a measure of a compound's inhibition (50% inhibition). | ||