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Cmax (pharmacology)

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Cmax is a term used in pharmacokinetics refers to the maximum (or peak) concentration that a drug achieves in tested area after the drug has been administrated and prior to the administration of a second dose. Cmax is the opposite of Cmin, which is the minimum (or trough) concentration that a drug achieves after dosing.[1]

Tmax is the term used in pharmacokinetics to describe the time at which the Cmax is observed. [2]

After an intravenous administration, Cmax and Tmax are closely dependent on the experimental protocol, since the concentrations are always decreasing after the dose. But after oral administration,Cmax and Tmax are dependent on the extent, and the rate of drug absorption and the disposition profile of the drug. They could be used to characterize the propertied of different formulations in the same subject. [3]

Short term drug side effects are most likely to occur at or near the Cmax whereas the therapeutic effect of drug with sustained duration of action usually occurs at concentrations slightly above the Cmin. [4]

The Cmax is often measured in an effort to show bioequivalence between a generic and innovator drug product.[5]

References

  1. ^ Tracy TS (2004). "Pharmacokinetics". In Stitzel RE, Craig CF (ed.). Modern pharmacology with clinical applications. Hagerstwon, MD: Lippincott Williams & Wilkins. p. 49. ISBN 0-7817-3762-1.
  2. ^ http://www.lexjansen.com/phuse/2006/st/st03.pdf
  3. ^ ting says
  4. ^ Urso R, Blardi P, Giorgi G (2002). "A short introduction to pharmacokinetics". Eur Rev Med Pharmacol Sci. 43 (10): 33–44. PMID 12708608. {{cite journal}}: Unknown parameter |month= ignored (help)CS1 maint: multiple names: authors list (link)
  5. ^ Midha KK, Rawson MJ, Hubbard JW (2005). "The bioequivalence of highly variable drugs and drug products". Int J Clin Pharmacol Ther. 6 (2–3): 485–98. PMID 16240706. {{cite journal}}: Unknown parameter |month= ignored (help)CS1 maint: multiple names: authors list (link)