European Journal of Clinical Pharmacology

, Volume 11, Issue 1, pp 57–64 | Cite as

Model independent derivation of general equations for the “first-pass” effect and extra-hepatic drug elimination

  • D. P. Vaughan


A general expression for the ratio of areas below the blood concentration-time curves after intravenous and oral drug administration is derived. This derivation does not require the assumption of a specific compartmental model to describe drug distribution within the body. Similarly an expression for the amount of drug metabolised in the liver is derived. The latter expression is used to estimate the extent of extra-hepatic drug elimination from the body.

Key words

General equation pharmacokinetics first pass effect extra-hepatic drug elimination 


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Copyright information

© Springer-Verlag 1977

Authors and Affiliations

  • D. P. Vaughan
    • 1
  1. 1.School of Pharmacy and Biology, Sunderland, PolytechnicSunderlandUK

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