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Metabolite to parent drug concentration ratio as a function of parent drug extraction ratio: Cases of nonportal route of administration

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Abstract

The ratio of metabolite to parent drug concentration (Cm/Cp)of a medium or high extraction ratio (E>0.1)drug administered intravenously has been shown to depend on intrinsic clearance of drug by other metabolic routes (CLr,int)as well as on organ blood flow (Q).In contrast, for a low extraction ratio drug given intravenously or for any drug given by a portal route, this ratio is equal to the ratio of formation clearance (CLf,int)and metabolite clearance (CLm,int).The sensitivity of Cm/Cpto changes in CLr,int and CLf,int has been analyzed quantitatively. It was shown to be dependent on the fraction metabolized to that particular metabolite (fm).

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Authors and Affiliations

  1. Department of Pharmaceutics, School of Pharmacy, University of Washington, BG-20, 98195, Seattle, Washington

    Elizabeth A. Lane & René H. Levy

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  1. Elizabeth A. Lane
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  2. René H. Levy
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Additional information

Supported in part by National Institutes of Health National Research Service Awards GM07348 and GM-07750 from the National Institute of General Medical Sciences and NINCDS Research Grant NS-04053 and NINCDS Research Contract NO l-NS-1-2282.

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Lane, E.A., Levy, R.H. Metabolite to parent drug concentration ratio as a function of parent drug extraction ratio: Cases of nonportal route of administration. Journal of Pharmacokinetics and Biopharmaceutics 9, 489–496 (1981). https://doi.org/10.1007/BF01060891

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  • DOI: https://doi.org/10.1007/BF01060891

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