C_min is a term used in pharmacokinetics for the minimum

blood plasma Blood plasma is a light amber-colored liquid component of blood in which blood cells are absent, but contains proteins and other constituents of whole blood in suspension. It makes up about 55% of the body's total blood volume. It is the intr ...

concentration reached by a drug during the time interval between administration of two doses. This definition is slightly different from C_trough, the concentration immediately prior to administration of the next dose. C_min is the opposite of C_max, the maximum concentration that the drug reaches. C_min must be above certain thresholds, such as the

minimum inhibitory concentration In microbiology, the minimum inhibitory concentration (MIC) is the lowest concentration of a chemical, usually a drug, which prevents visible growth of a bacterium or bacteria. MIC depends on the microorganism, the affected human being (in vivo only ...

(MIC), to achieve a

therapeutic effect Therapeutic effect refers to the response(s) after a treatment of any kind, the results of which are judged to be useful or favorable. This is true whether the result was expected, unexpected, or even an unintended consequence. An adverse effect ( ...

. In most cases C_min is directly measurable. At steady state the minimum plasma concentration can also be calculated using the following equation: :

C_= \frac\times\

:''S'': salt factor :''F'':

bioavailability In pharmacology, bioavailability is a subcategory of absorption and is the fraction (%) of an administered drug that reaches the systemic circulation. By definition, when a medication is administered intravenously, its bioavailability is 100%. Ho ...

:''D'': dose :''k'': elimination constant :''k_a'': absorption constant :''V_d'':

volume of distribution In pharmacology, the volume of distribution (VD, also known as apparent volume of distribution, literally, ''volume of dilution'') is the theoretical volume that would be necessary to contain the total amount of an administered drug at the same c ...

:''τ'': dosing interval C_min is also an important parameter in

and

bioequivalence Bioequivalence is a term in pharmacokinetics used to assess the expected in vivo biological equivalence of two proprietary preparations of a drug. If two products are said to be bioequivalent it means that they would be expected to be, for all ...

studies, it is part of the pharmacokinetic information recommended for submission of investigational new drug applications.https://www.fda.gov/downloads/Drugs/.../Guidances/ucm070124.pdf

References

Pharmacokinetic metrics {{pharmacology-stub