Koncentrationsresponssambandet

Koncentrationsresponssambandet is the relationship between the concentration of a chemical substance and the magnitude of the biological response it elicits. It is a central concept in pharmacology, toxicology and environmental health, used to characterize potency and efficacy and to compare substances across conditions. In most cases, the curve increases with concentration, but responses can also decrease with exposure in cases of antagonists or toxic processes.

A common mathematical representation is the Hill equation: E(C) = E0 + (Emax − E0) * C^n / (EC50^n + C^n), where E is the effect at concentration C, E0 is the baseline response, Emax the maximum effect, EC50 the concentration producing half-maximal response, and n the Hill coefficient describing the slope. The curve may also be described with logistic or sigmoid forms. From these curves, researchers extract potency (EC50) and efficacy (Emax), and assess the steepness via n, which can indicate cooperative interactions.

Data for koncentrationsresponssambandet are obtained from in vitro assays or in vivo studies, and use nonlinear regression or other curve-fitting methods. Interpretation requires consideration of time dependence, exposure duration, species and system differences, and potential non-monotonicity, where the response changes direction at different concentrations.

Applications include drug development, risk assessment, and regulatory decision-making, where concentration-response information informs dosing strategies, safety margins, and environmental exposure limits. Limitations include model assumptions, confounding factors, and extrapolation beyond tested conditions.