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Free Drug Theory

The ADME Encyclopedia

Synonyms

Free drug hypotheiss

Definition

The free drug theory (sometimes also termed free drug hypothesis) provides a conceptual framework increasingly used to understand pharmacokinetics/pharmacodynamics (PK/PD) relationships [1]. It underlines the central role of free (or unbound) drug concentration at the site of action (the surroundings of the drug target) as determinant of in vivo efficacy and pharmacokinetics. A deep understanding of this theory can also be helpful to establish in vitro-in vivo correlations or, alternatively, to provide explanations to absence of clear correlations between in vitro and in vivo studies.

The free drug theory can be enunciated in two parts [2].

The free drug theory part I states that, at steady state, the unbound drug concentration will be the same on both sides of a biological membrane. Provided that some requisites are verified, thus, the free drug concentration will be the same in plasma, extracellular fluid, and intracellular fluid.

The free...

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Authors and Affiliations

  1. Laboratory of Bioactive Research and Development (LIDeB), Department of Biological Sciences, Faculty of Exact Sciences, University of La Plata (UNLP), La Plata, Buenos Aires, Argentina

    Alan Talevi & Carolina L. Bellera

  2. Argentinean National Council of Scientific and Technical Research (CONICET) - CCT La Plata, Buenos Aires, Argentina

    Alan Talevi & Carolina L. Bellera

Authors
  1. Alan Talevi
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  2. Carolina L. Bellera
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Correspondence to Alan Talevi .

Section Editor information

  1. Medicinal Chemistry, Department of Biological Sciences, Faculty of Exact Sciences, National University of la Plata (UNLP) - Argentinean National Council of Scientific and Technical Research (CONICET), La Plata, Buenos Aires, Argentina

    Alan Talevi

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Talevi, A., Bellera, C.L. (2021). Free Drug Theory. In: The ADME Encyclopedia. Springer, Cham. https://doi.org/10.1007/978-3-030-51519-5_51-1

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  • DOI: https://doi.org/10.1007/978-3-030-51519-5_51-1

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  • Print ISBN: 978-3-030-51519-5

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Chapter history

  1. Latest

    Free Drug Theory
    Published:
    04 December 2021

    DOI: https://doi.org/10.1007/978-3-030-51519-5_51-2

  2. Original

    Free Drug Theory
    Published:
    02 June 2021

    DOI: https://doi.org/10.1007/978-3-030-51519-5_51-1

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