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Peak-to-trough ratio
Pharmacokinetic metrics / From Wikipedia, the free encyclopedia
Peak-to-trough ratio (PTR), also known as peak-to-trough variation or peak-to-trough fluctuation, is a parameter in pharmacokinetics which is defined as the ratio of Cmax (peak) concentration and Cmin (trough) concentration over a dosing interval for a given drug.[1][2] A drug with an elimination half-life of 24 hours taken once per day will have a peak-to-trough ratio of approximately 2.[1] Peak-to-trough ratio is proportional to half-life and to dosing interval, with longer half-lives and shorter dosing intervals giving smaller ratios.[3]
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