{{Distinguish|C minor}}{{Short description|Minimum blood plasma concentration of a drug during the time between two doses}} {{cs1 config|name-list-style=vanc|display-authors=6}} {{DISPLAYTITLE:''C''<sub>min</sub>}} {{Use dmy dates|date=May 2023}} {{math|'''''C''<sub>min</sub>'''}} 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 {{math|''C''<sub>trough</sub>}}, the concentration immediately prior to administration of the next dose.<ref>{{cite book | vauthors = Weimann HJ, Cawello W, Brett M, Zimmermann H, Pabst G, Sierakowski B, Giesche R, Baumann A | chapter = Drug concentrations and directly derived parameters | title = Parameters for Compartment Free Pharmacokinetics: Standardisation of Study Design, Data Analysis and Reporting | location = Aachen, Germany | pages = 25–40 | year = 1999 | url = https://books.google.com/books?id=EzqwAAAACAAJ | publisher = Shaker-Verlag | isbn = 978-3-8265-4767-6 | oclc = 44511664 }} (pages 31–34 in 2003 edition)</ref> {{math|''C''<sub>min</sub>}} is the opposite of {{math|''C''<sub>max</sub>}}, the maximum concentration that the drug reaches. {{math|''C''<sub>min</sub>}} must be above certain thresholds, such as the minimum inhibitory concentration (MIC), to achieve a therapeutic effect.<ref>{{cite journal | vauthors = Dalton BR | title = 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 | journal = Microorganisms | volume = 11 | issue = 3 | pages = 567 | date = February 2023 | pmid = 36985141 | pmc = 10051726 | doi = 10.3390/microorganisms11030567 | doi-access = free }}</ref>
In most cases {{math|''C''<sub>min</sub>}} is directly measurable. At steady state the minimum plasma concentration can also be calculated using the following equation:<ref>{{cite book |author1-last = Dhillon |author1-first=Soraya|author2-last= Gill|author2-first= Kiren | chapter=Basic pharmacokinetics | title =Clinical pharmacokinetics | date=2006 | pages = 1–44 | url = http://www.pharmpress.com/files/docs/clinical_pharmacokinetics_samplechapter.pdf | archive-url = https://web.archive.org/web/20180329011004/http://www.pharmpress.com/files/docs/clinical_pharmacokinetics_samplechapter.pdf | archive-date = 29 March 2018 |publisher=Pharmaceutical Press|isbn=9780853695714}}</ref> <math display="block">C_{min} = \frac{SFDk_a}{V_d(k_a-k_e)} \times \left( \frac{e^{-k_e\tau}}{1-e^{-k_e\tau}}-\frac{e^{-k_a\tau}}{1-e^{-k_a\tau}} \right)</math>
:{{mvar|S}} = Salt factor :{{mvar|F}} = Bioavailability :{{mvar|D}} = Dose :{{math|''k''{{sub|e}}}} = Elimination rate constant :{{math|''k''{{sub|a}}}} = Absorption rate constant :{{math|''V''{{sub|d}}}} = Volume of distribution :{{mvar|τ}} = Dosing interval
{{math|''C''<sub>min</sub>}} 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.<ref>{{cite web | url = http://www.fda.gov/downloads/Drugs/.../Guidances/ucm070124.pdf | work = Guidance for Industry | title = Bioavailability and Bioequivalence, Studies for Orally Administered Drug Products — General Considerations | date = March 2003 | publisher = Center for Drug Evaluation and Research (CDER), U.S. Food and Drug Administration | archive-url = https://web.archive.org/web/20130319082058/http://www.fda.gov/downloads/Drugs/.../Guidances/ucm070124.pdf | archive-date = 19 March 2013 }}</ref>
== References == {{Reflist}}
Category:Pharmacokinetic metrics {{pharmacology-stub}}