What is the pA2 of a drug?
pA2. pA2 is a measure of the potency of an antagonist. It is the negative logarithm of the molar concentration of an antagonist that would produce a 2-fold shift in the concentration response curve for an agonist.
What is pD2 value in pharmacology?
pD2′ value • Measures the affinity of either non competitive or irreversible competitive antagonist for a specific receptor • Defined as –log(B) which will decrease the maximum effect of agonist by 50% • Higher the pD2 value ,higher the potency.
How is pD2 calculated?
pD2 value (pD2 = -log EC50) was calculated using indometazine in guinea pig trachea.
What is the PKB value of an antagonist?
pkB = log(conc. ratio – 1) – log(antagonist conc.) For a competitive antagonist (i.e. one where the slope of the Schild plot equals 1), the pKB is theoretically equal to the pA2 value.
What does pA2 mean?
What does high pA2 mean?
The higher the value for pA2, the higher the affinity of B is to its receptor.
What does a high pA2 value mean?
What is the pA2 value of atropine?
Atropine yielded a pA2 value of 8.60+0.08.
What is the pA2 value of atropine against acetylcholine?
8.60 +/- 0.08
Atropine yielded a pA2 value of 8.60 +/- 0.08.
What is ec50 in pharmacology?
In pharmacology, the potency of a compound is expressed as the half-maximal effective concentration (EC50), which refers to the concentration of a drug that induces a response halfway between the baseline and maximum.
What is the antagonist?
Definition of antagonist 1 : one that contends with or opposes another : adversary, opponent political antagonists. 2 : an agent of physiological antagonism: such as.
What is the pA2 of atropine?
What is EC50 toxicity?
EC50(50% Effective Concentration)：Effective Concentration 50 The Lethal Concentration 50 (LC50) is the concentration of a substance in water causing a death (50% of the tested population) to aquatic life.
What is IC50 value in cytotoxicity?
The IC50 is defined as “the concentration of an inhibitor where the response (or binding) is reduced by half.” So, if you are testing viability via an MTT assay, the dose of cytotoxic compound at which you achieve 50% viability will be the IC50.
What is antagonist in pharmacology?
Listen to pronunciation. (an-TA-guh-nist) In medicine, a substance that stops the action or effect of another substance. For example, a drug that blocks the stimulating effect of estrogen on a tumor cell is called an estrogen receptor antagonist.
What does the pA2 value Show?
The pA2 value indicates the concentration of antagonist when double the agonist is required to have the same effect on the receptor as when no antagonist is present.
What does the term toxicity mean?
Definition of toxicity : the quality or state of being toxic: such as. a : the quality, state, or relative degree of being poisonous measuring the toxicity level of the soil The toxicity of some chemical agents degrades significantly over time, so it is unclear how lethal the stockpiles are.—
What is threshold level of toxicity?
When a chemical causes a defined form of toxicity, the threshold is the maximum exposure when this toxicity does not occur. It is an operational parameter and is limited in its interpretation and applicability.
How is IC50 cytotoxicity calculated?
IC50 values were calculated by linear approximation regression of the percentage survival versus the drug concentration. Cell survival rate (%)=(a-c)/(b-c) x100 (a=absorbance at each concentration of the anticancer reagent, b=absorbance at 0 µM of the anticancer reagent, and c=absorbance of the blank).