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A method for calculating the mean absorption time of drugs undergoing reversible and first‐pass metabolism
Author(s) -
Cheng Haiyung,
Shum Linyee
Publication year - 1993
Publication title -
biopharmaceutics and drug disposition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.419
H-Index - 58
eISSN - 1099-081X
pISSN - 0142-2782
DOI - 10.1002/bdd.2510140107
Subject(s) - metabolite , chemistry , pharmacokinetics , absorption (acoustics) , drug , elimination rate constant , drug metabolism , oral administration , absorption rate , reaction rate constant , constant (computer programming) , chromatography , pharmacology , metabolism , kinetics , biochemistry , materials science , medicine , physics , computer science , volume of distribution , quantum mechanics , composite material , programming language
A method has been derived for calculating the mean absorption time of an oral drug and its interconversion metabolite which is generated from the drug systemically and presystemically. The method evolves from the convolution integral and requires plasma AUC and AUMC values after separate intravenous administration of the drug and its interconversion metabolite and oral administration of the drug. It can also be used to calculate the mean input time of a drug undergoing reversible metabolism and administered by any other extravascular route. Results of a simulation study using both errorless and errant data indicate that, when the absorption rate constant of a drug or its interconversion metabolite is not much larger than the apparent elimination rate constant, the proposed method performs satisfactorily. However, when the absorption rate constant of a drug or its interconversion metabolite is much larger than the apparent elimination rate constant, the proposed method appears to be inaccurate.