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A calibration curve plot showing limit of detection (LOD), limit of quantification (LOQ), dynamic range, and limit of linearity (LOL).. In analytical chemistry, a calibration curve, also known as a standard curve, is a general method for determining the concentration of a substance in an unknown sample by comparing the unknown to a set of standard samples of known concentration. [1]
The area under the effect curve (AUEC) is an integral of the effect of a drug over time, estimated as a previously-established function of concentration. It was proposed to be used instead of AUC in animal-to-human dose translation, as computer simulation shows that it could cope better with half-life and dosing schedule variations than AUC.
The EC 50 of a quantal dose response curve represents the concentration of a compound where 50% of the population exhibit a response, [5] after a specified exposure duration. For clarification, a graded dose response curve shows the graded effect of the drug (y axis) over the dose of the drug (x axis) in one or an average of subjects.
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.
Each curve corresponds to a different Hill coefficient, labeled to the curve's right. The vertical axis displays the proportion of the total number of receptors that have been bound by a ligand. The horizontal axis is the concentration of the ligand. As the Hill coefficient is increased, the saturation curve becomes steeper.
The calibration curve that does not use the internal standard method ignores the uncertainty between measurements. The coefficient of determination (R 2) for this plot is 0.9985. In the calibration curve that uses the internal standard, the y-axis is the ratio of the nickel signal to the yttrium signal.
That is, the closer time points are, the closer the trapezoids reflect the actual shape of the concentration-time curve. The number of time points available in order to perform a successful NCA analysis should be enough to cover the absorption, distribution and elimination phase to accurately characterize the drug.
Left shift of the curve is a sign of hemoglobin's increased affinity for oxygen (e.g. at the lungs). Similarly, right shift shows decreased affinity, as would appear with an increase in either body temperature, hydrogen ions, 2,3-bisphosphoglycerate (2,3-BPG) concentration or carbon dioxide concentration.