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Pharmacokinetics of Nifedipine Slow Release Tablet in Mexican Subjects: Further Evidence for an Oxidation Polymorphism
Author(s) -
HoyoVadillo C.,
CastañedaHernández G.,
Herrera J. E.,
VidalGárate J.,
MorenoRamos A.,
Chávez F.,
Hong E.
Publication year - 1989
Publication title -
the journal of clinical pharmacology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.92
H-Index - 116
eISSN - 1552-4604
pISSN - 0091-2700
DOI - 10.1002/j.1552-4604.1989.tb03425.x
Subject(s) - nifedipine , pharmacokinetics , kinetics , pharmacology , chemistry , ingestion , oral administration , half life , bioavailability , medicine , calcium , physics , quantum mechanics
Nifedipine kinetics after ingestion of 20 mg slow release tablets were studied in 12 young, healthy, Mexican subjects. Plasma levels were determined by a nifedipine‐specific HPLC assay. Levels rose after drug administration reaching a maximum concentration of 48.7 ± 7.3 ng/ml in 2.1 ± 0.7 h (mean ± SEM). Concentrations then decayed with a terminal half‐life of 16.9 ± 3.1 hours. AUC was 526 ± 62 ng h/ml. Five individuals were fast and seven were slow nifedipine metabolizers, according to the AUC criterion proposed by Kleinbioesem and coworkers. Individual AUC/Dose values from this and from other two studies on oral nifedipine kinetics in Mexicans were cumulated and the frequency histogram and probit analyses were performed (N = 30). A bimodal distribution was clearly observed. Fast and slow metabolizers were distinguished as those subjects with AUC/Dose values either lower or higher than 22.5 ng h/ml mg. Unlike European populations, it appears that slow metabolization is more frequent in Mexicans. Data strongly support the hypothesis of the existence of a polymorphism concerning nifedipine disposition kinetics due to genetic basis.