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Intravenous administration

Scheme or diagram

Diagram XIX-1 Two Compartment Pharmacokinetic Model

Differential equation

The differential equation for drug in the central compartment following intravenous bolus administration is:-

Equation XIX-1 Differential Equation for the Central Compartment

The kel * X1 term describes elimination of the drug from the central compartment, while the k12 * X1 and k21 * X2 terms describe the distribution of drug between the central and peripheral compartments.

Integrated equation

Integration of this equation (using Laplace transforms) leads to a biexponential equation for plasma concentration as a function of time.


Cp = A * e- * t + B * e- * t with > .

The A, B, , and terms were derived from the microconstants during the integration process. They are functions of the microconstant k12, k21, kel and V1

+ = kel + k12 + k21
* = kel * k21

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A is:
B is:

This page was last modified: 19 October 2002

Copyright 2001 David W.A. Bourne

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