Search results
Results From The WOW.Com Content Network
For a response of 0.25a.u., Drug B is more potent, as it generates this response at a lower concentration. For a response of 0.75a.u., Drug A is more potent. a.u. refers to "arbitrary units". In pharmacology , potency or biological potency [ 1 ] is a measure of a drug's biological activity expressed in terms of the dose required to produce a ...
Intrinsic activity (IA) and efficacy (E max) refer to the relative ability of a drug-receptor complex to produce a maximum functional response. This must be distinguished from the affinity, which is a measure of the ability of the drug to bind to its molecular target, and the EC 50, which is a measure of the potency of the drug and which is proportional to both efficacy and affinity.
Efficacy is the ability to perform a task to a satisfactory or expected degree. The word comes from the same roots as effectiveness , and it has often been used synonymously, although in pharmacology a distinction is now often made between efficacy and effectiveness .
It is commonly used as a measure of a drug's potency, although the use of EC 50 is preferred over that of 'potency', which has been criticised for its vagueness. [3] EC 50 is a measure of concentration, expressed in molar units (M), where 1 M is equivalent to 1 mol/L.
In pharmacology, an effective dose (ED) or effective concentration (EC) is the dose or concentration of a drug that produces a biological response. [1] [2] The term "effective dose" is used when measurements are taken in vivo, while "effective concentration" is used when the measurements are taken in vitro.
Potency of drug is the measure of its effectiveness, EC 50 is the drug concentration of a drug that produces an efficacy of 50% and the lower the concentration the higher the potency of the drug therefore EC 50 can be used to compare potencies of drugs.
The graph shown represents the conc-response for two hypothetical receptor agonists, plotted in a semi-log fashion. The curve toward the left represents a higher potency (potency arrow does not indicate direction of increase) since lower concentrations are needed for a given response. The effect increases as a function of concentration.
The parameters of the dose response curve reflect measures of potency (such as EC50, IC50, ED50, etc.) and measures of efficacy (such as tissue, cell or population response). A commonly used dose–response curve is the EC 50 curve, the half maximal effective concentration, where the EC 50 point is defined as the inflection point of the curve.