lowmicromolar

Low micromolar refers to concentrations in the micromolar range (µM) that are small but sufficient to produce a measurable effect in biological or chemical assays. A micromolar concentration equals one micromole per liter (1 µM = 1 × 10^-6 mol/L). The qualifier “low” is relative and context dependent; in many pharmacological assays, compounds with activity around 1–10 µM are described as having low micromolar potency, whereas higher affinities are described as nanomolar (nM) or sub-nanomolar. Conversely, 10–100 µM is often termed mid- to high-micromolar.

In practice, low micromolar potency is used to characterize inhibitors, activators, or ligands in vitro, for example by reporting IC50, Kd, or EC50 values. The exact interpretation depends on assay conditions, including substrate concentration and enzyme kinetics. While low micromolar potency can indicate useful activity, medicinal chemistry aims to improve potency to sub-micromolar or nanomolar ranges for therapeutic candidates, balancing potency with selectivity and pharmacokinetic properties.

Practical considerations include solubility limits, solvent effects (e.g., DMSO), and assay interference at higher concentrations. It is also important to report experimental conditions, as activity figures are sensitive to assay setup and cell type.

See also: nanomolar, micromolar, millimolar, IC50, Kd, EC50.