Concentration Response Relationships

Question 1

Affinity

Answer 1

The extent to which a drug binds to receptors at any given drug concentration

Question 1

Efficacy

Answer 1

The maximum effect that a drug will produce on its target

Question 2

EC50

Answer 2

Half maximal effective concentration.
Concentration that produces a response of 50% (with respect to maximal).
Molar concentration of an agonist.
Lower the EC50- stronger (more potent the agonist).

Question 3

IC50

Answer 3

Half maximal inhibitory concentration.
Concentration that produces 50% inhibition (with respect to maximal response).
Molar concentration of an antagonist.
The lower the IC50 the stronger (more potent) the antagonist.

Question 4

pD2/pEC50

Answer 4

Negative log10 of the EC50. A larger number indicates a more potent drug.

Question 5

pIC50

Answer 5

Negative log10 of the IC50. A larger number indicates a more potent drug.

Question 6

ED50

Answer 6

Dose of drug required to achieve desired pharmacological effect in half the population (used more in clinical settings).