Bioavailability and its assessment

Authors

  • P. L. TOUTAIN,

    1. UMR 181 Physiopathologie et Toxicologie Expérimentales INRA/ENVT, Ecole Nationale Vétérinaire de Toulouse, Toulouse cedex 03, France
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  • A. BOUSQUET-MÉLOU

    1. UMR 181 Physiopathologie et Toxicologie Expérimentales INRA/ENVT, Ecole Nationale Vétérinaire de Toulouse, Toulouse cedex 03, France
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P.L. Toutain, UMR 181 Physiopathologie et Toxicologie Expérimentales INRA/ENVT, Ecole Nationale Vétérinaire de Toulouse, 23, chemin des Capelles, 31076 Toulouse cedex 03, France. E-mail: pl.toutain@envt.fr

Abstract

Bioavailability is a key pharmacokinetic parameter which expresses the proportion of a drug administered by any nonvascular route that gains access to the systemic circulation. Presented in this review are the different approaches to measurement of bioavailability (absolute and relative), including the case in which intravenous administration is impossible. The rate of drug absorption is also discussed with special emphasis on the possible difficulties encountered using Cmax and Tmax or curve fitting to evaluate the rate of drug absorption.

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