Pharmacokinetics IV: Absorptive Route of Administration Plasma Concentration-Time Data

Abstract

Plasma concentration-time data are useful for determining the rate constants for absorption and elimination (and, hence, the corresponding half lives) following administration via an absorptive route. The elimination rate constant (K _e ) and the apparent volume of distribution (V _d ) are best obtained from concentration-time data following intravenous administration as described in Procedure 26. However, if the only data available are from administration that uses an absorptive route, the plasma-time data are still useful. The two-compartment model (illustrated in Figure 29.1) is frequently used.

This computational algorithm is based on the standard two-compartment model in which the loss of drug from the plasma is due only to elimination via excretion and metabolism.