Potency is a quantity of medicine commotion articulated regarding the quantity needed to create an result
of given strength. Drugs with high potency evoke a certain reaction at low mixture with a drug with low
potency evokes the same response only at higher levels.
Affinity and efficacy
The level of either high potency or low potency depends on the affinity and efficacy. It is the power of
the medicine to combine to a receptor. The second, efficacy is the connection amid receptor tenancy and
the aptitude to start a retort at the cellular, molecular, system level or tissue. In this association, the
response is directly proportional to the effect and it relies on both drug-bound receptor and drug binding
and the response is formed therefore potency is dependent on both efficacy and affinity. The agonist,
ligand drug or hormone which binds to the receptor inaugurates the response is usually cut to A or D.
Under a particular concentration of agonist [A]), E is very little to calculate nevertheless at higher levels
it turn out to be substantial and increases with agonist attentiveness [A] til at adequately high
concentrations it cannot be improved by raising [A] and asymptotes to a maximum.
A maximum possible effect for an agonist is Emax.
The convergence of A at which E is 50% of Emax is referred as the partially maximal effectual mixture
and is shortened [A]50, or most commonly EC50. Therefore the word potency can be explained in short
form as [A]50 value where the lower the [A]50, the less drug concentration is needed to produce 50% of
maximum effect and the higher the potency
However, highpotency does not mean more side effects. The part of the drug molecule that forms the
atoms and groups which bind to the receptor is known as The pharmacophore. The part of the particle
which isn’t occupied in binding except may hinder with binding slightly is the “auxophore.