One-compartment kinetics.

The mathematical development of the equations needed to determine the plasma concentrations of drug in a one-compartment pharmacokinetic model are developed from first principles and are illustrated (with caution) by the use of morphine given by bolus or continuous i.v. injection or by a simulated i.m. injection. The equations allow the calculation of concentrations, given a knowledge of what drug is currently present, what are the sizes of the boluses by either i.m. or i.v. injection and what is the constant infusion rate. What happens when changes occur is also illustrated. The development illustrates the principles needed to apply to more complex models.