Cmin Explained

is a term used in pharmacokinetics for the minimum blood plasma concentration reached by a drug during a dosing interval, which is the time interval between administration of two doses. This definition is slightly different from, the concentration immediately prior to administration of the next dose.^[1] is the opposite of, the maximum concentration that the drug reaches. must be above certain thresholds, such as the minimum inhibitory concentration (MIC), to achieve a therapeutic effect.^[2]

In most cases is directly measurable. At steady state the minimum plasma concentration can also be calculated using the following equation:^[3] $$C\_\; =\; \backslash frac\; \backslash times\; \backslash left(\backslash frac-\backslash frac\; \backslash right)$$

= Salt factor

= Bioavailability

= Dose

= Elimination rate constant

= Absorption rate constant

= Volume of distribution

= Dosing interval

is also an important parameter in bioavailability and bioequivalence studies, it is part of the pharmacokinetic information recommended for submission of investigational new drug applications.^[4]

Notes and References

1. Book: Weimann HJ, Cawello W, Brett M, Zimmermann H, Pabst G, Sierakowski B, Giesche R, Baumann A . Drug concentrations and directly derived parameters . Parameters for Compartment Free Pharmacokinetics: Standardisation of Study Design, Data Analysis and Reporting . Aachen, Germany . 25–40 . 1999 . Shaker-Verlag . 978-3-8265-4767-6 . 44511664 . (pages 31–34 in 2003 edition)
2. Dalton BR . What Is the Best Vancomycin Therapeutic Drug Monitoring Parameter to Assess Efficacy? A Critical Review of Experimental Data and Assessment of the Need for Individual Patient Minimum Inhibitory Concentration Value . Microorganisms . 11 . 3 . 567 . February 2023 . 36985141 . 10051726 . 10.3390/microorganisms11030567 . free .
3. Book: Dhillon S, Gill K . Basic pharmacokinetics . Clinical pharmacokinetics . 2006 . 1–44 . https://web.archive.org/web/20180329011004/http://www.pharmpress.com/files/docs/clinical_pharmacokinetics_samplechapter.pdf . 29 March 2018 .
4. Web site: Bioavailability and Bioequivalence, Studies for Orally Administered Drug Products — General Considerations . Guidance for Industry . March 2003 . Center for Drug Evaluation and Research (CDER), U.S. Food and Drug Administration . https://web.archive.org/web/20130319082058/http://www.fda.gov/downloads/Drugs/.../Guidances/ucm070124.pdf . 19 March 2013 .