- On 12 Nov 1998 at 13:38:26, Maria Durisova (exfamadu.at.savba.savba.sk) sent the message

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

formulations:

DF modeling, i.e. building dynamic models describing the drug

fate

and

DE modeling, i.e. building dynamic models describing the drug

effect.

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,

231-241.

3. Dedik L., Durisova M., Comput. Methods Progr. Biomed.,

51, 1996, 183-192.

4. Dedik L., Durisova M., Ecol. Modell., 101, 1997, 175-184.

Dr.Maria Durisova,PhD

Institute of Experimental Pharmacology

Slovak Academy of Sciences

and

Assoc.Prof.Ladislav Dedik,PhD

Department of Automation and Measurement

Slovak University of Technology

Bratislava

Slovak Republic

Want to post a follow-up message on this topic? If this link does not work with your browser send a follow-up message to PharmPK@boomer.org with "Dynamic models" as the subject

PharmPK Discussion List Archive Index page

Copyright 1995-2010 David W. A. Bourne (david@boomer.org)