Back to the Top
To the PharmPK List,
Recently we stressed that if the behavior of the systems
describing the drug fate and of the systems describing the
drug effect is DEPENDENT on the state of these systems (which
is the usual case) both groups of these systems are DYNAMIC
systems. Furthermore, we have suggested to use the terms
"response of the system describing the drug fate" and
"response of the system describing the drug effect" instead
of "pharmacokinetic curve" and "pharmacodynamic curve",
respectively. Later, we tentatively proposed the term
"DF/DE" as an acronym for Drug Fate/Drug Effect modeling. The
use of this term would yield the following reasonable
DF modeling, i.e. building dynamic models describing the drug
DE modeling, i.e. building dynamic models describing the drug
It may be useful to add the following comments:
The terms pharmacokinetics/pharmacodynamics were created in
pharmacology by adopting the terms kinetics/dynamics taken
from mechanics, and several approaches have been developed
for pharmacokinetic modeling, while others for
pharmacodynamic modeling. This categorization has become very
common, nevertheless, it is at variance with the properties
of the mathematical structures adopted for MODELING purposes.
In principle, not only the systems describing the fate and
effect of substances are DYNAMIC systems, but their
mathematical models are also DYNAMIC MODELS. For example,
ordinary differential equations and their solutions in the
form of multiexponential functions, i.e. the mathematical
structures used to describe the drug fate in the body by the
well known compartment models, are also DYNAMIC models (1).
The term "kinetic model" (where "kinetic" implies movement)
is appropriate for the description of a static system whose
behavior in not dependent on its state. On the other hand,
the dynamic model is the model of the behavior of the dynamic
system. It describes how one state of the system develops
into another state as a consequence of the force producing
this development. In pharmacology such "a force" is usually
the drug input into the body.
On using the dynamic system approach, dynamic models of
dynamic systems describing the fate or effect of substances
can be built in a METHODICALLY UNIFORM way. Moreover, if
these systems are linear (exactly speaking they can be
sufficiently approximated by linear models), their modeling
can be performed on employing FORMALLY IDENTICAL mathematical
models, irrespective of the fact whether these systems are in
steady state (2,3) or not (4).
1. B. Hannon, M. Ruth, Dynamic Modeling, Springer-Verlag, New
York, 1994, 248 pp.
2. Dedik L., Durisova M., Int. J. Bio-Med. Comput., 39, 1995,
3. Dedik L., Durisova M., Comput. Methods Progr. Biomed.,
51, 1996, 183-192.
4. Dedik L., Durisova M., Ecol. Modell., 101, 1997, 175-184.
Institute of Experimental Pharmacology
Slovak Academy of Sciences
Department of Automation and Measurement
Slovak University of Technology
PharmPK Discussion List Archive Index page
Copyright 1995-2010 David W. A. Bourne (firstname.lastname@example.org)