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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.
Potency is a measure of how much a drug is required in order to produce a particular effect. Therefore, only a small dosage of a high potency drug is required to induce a large response. The other terms used to measure the ability of a drug to trigger a response are: Intrinsic Activity which defines: Agonists as having Intrinsic Activity = 1
The lower the EC 50, the less the concentration of a drug is required to produce 50% of maximum effect and the higher the potency. The EC 10 and EC 90 concentrations to induce 10% and 90% maximal responses are defined similarly. There is a wide range of EC 50 values of drugs; they are typically
In pharmacology, efficacy (E max) is the maximum response achievable from an applied or dosed agent, for instance, a small molecule drug. [2] Intrinsic activity is a relative term for a drug's efficacy relative to a drug with the highest observed efficacy. [3] It is a purely descriptive term that has little or no mechanistic interpretation.
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.
As the lipophilicity of ionizable compounds is strongly dependent of pH, the distribution coefficient logD, or a logP vs pH curve may be used instead. Potency at the biological target. High potency (high value of pIC 50) is a desirable attribute in drug candidates, as it reduces the risk of non-specific, off-target pharmacology at a given ...
Acute use (1–3 days) yields a potency about 1.5× stronger than that of morphine and chronic use (7 days+) yields a potency about 2.5 to 5× that of morphine. Similarly, the effect of tramadol increases after consecutive dosing due to the accumulation of its active metabolite and an increase of the oral bioavailability in chronic use.