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LENNART K. PAALZOW AN. R. ACAD. NAC. FARM.

rentes modelos matemáticos que describen el comportamiento y las concentracio-
nes de estos medicamentos. Así cuando los medicamentos son administrados, su
concentración en los fluidos biológicos cambia con el tiempo, dando una curva de
perfil característico. La práctica clínica de la farmacocinética recibe la denomina-
ción de monitorización terapéutica de fármacos (TDM). La monotorización de
fármacos se realiza determinando las concentraciones de un fármaco en plasma
así como su intervalo de dosificación, mediante cuantificación de los niveles del
mismo en plasma de pacientes individualizados. También se consideran los fárma-
cos para los que es más adecuada su monitorización clínica y se describen los
métodos estadísticos disponibles y adecuados para la descripción del comporta-
miento de un fármaco según los niveles de concentración medidos.

Palabras clave: Farmacocinética.— Monitorización terapéutica de fárma-
cos (TDM).

INTRODUCTION

Pharmacokinetics is usually described as a science that describes
what happens to a drug in the body. It is a study of the time course
of drug and metabolite levels in different fluids, tissues and excreta
of the body and the mathematical relationships required to interpret
such data (1). The international development of pharmacokinetics as
a separate science has been very rapid during the last three decades,
but of course even before this period there were published a number
of seminal research that laid the foundation to this discipline.

Personally, I am very pleased to know that professor Torsten Teo-
rell, who was professor of physiology at our University, is considered
as the father of pharmacokinetics. Already in the summer 1937, he
wrote two famous articles (2, 3), which from the beginning nobody
really understood and most experts in Sweden considered almost as
rubbish and these papers were consequently forgotten. It took almost
30 years before researcher, especially in U.S.A., realized the impor-
tance of theses two articles and from around 1965 and onwards phar-
macokinetics started to develop rapidly. These papers of Teorell are
today considered as two of the most important articles in this area
and they are considered as the origins of pharmacokinetics. We also
have to remember that the development in pharmacokinetics was due
to the rapid development of new analytical techniques like gas chro-
matography, liquid chromatography, high-pressure liquid chromato-

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