Medicine:Cmin
Cmin 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 Ctrough, the concentration immediately prior to administration of the next dose.[1] Cmin is the opposite of Cmax, the maximum concentration that the drug reaches. Cmin must be above certain thresholds, such as the minimum inhibitory concentration (MIC), to achieve a therapeutic effect.[2]
In most cases Cmin is directly measurable. At steady state the minimum plasma concentration can also be calculated using the following equation:[3]
- S = Salt factor
- F = Bioavailability
- D = Dose
- ke = Elimination rate constant
- ka = Absorption rate constant
- Vd = Volume of distribution
- τ = Dosing interval
Cmin 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]
References
- ↑ "Drug concentrations and directly derived parameters". Parameters for Compartment Free Pharmacokinetics: Standardisation of Study Design, Data Analysis and Reporting. Aachen, Germany: Shaker-Verlag. 1999. pp. 25–40. ISBN 978-3-8265-4767-6. OCLC 44511664. https://books.google.com/books?id=EzqwAAAACAAJ. (pages 31–34 in 2003 edition)
- ↑ "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. doi:10.3390/microorganisms11030567. PMID 36985141.
- ↑ "Basic pharmacokinetics". Clinical pharmacokinetics. 2006. pp. 1–44. http://www.pharmpress.com/files/docs/clinical_pharmacokinetics_samplechapter.pdf. [bare URL PDF]
- ↑ "Bioavailability and Bioequivalence, Studies for Orally Administered Drug Products — General Considerations". Guidance for Industry. Center for Drug Evaluation and Research (CDER), U.S. Food and Drug Administration. March 2003. http://www.fda.gov/downloads/Drugs/.../Guidances/ucm070124.pdf.
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