The term “pharmacokinetics” (PK) is relatively young and was first introduced in 1953 (Wagner 1981). Although some of the concepts associated with pharmacokinetics are much older (eg, Michaelis–Menten equation in 1913, Hill equation in 1908), the study of pharmacokinetics and pharmacodynamics (PD) has only been popularized over the last 60 years. Since the early conceptions of compartmental PK analysis in the 1960s and noncompartmental analysis in the 1970s, the studies of PK and/or PD in drug development have advanced rapidly. These advancements are strongly correlated with the explosion of computers, especially personal computers (PCs). Computer speed and storage capacity have doubled approximately every 2 years over the last 40 years (Keyes 2006). Therefore, mathematical computation time has dramatically shortened over the same period of time.
The increased speed of computers as well as their storage capacity has led to the development of numerous computer software programs that now allow for the rapid solution of complicated pharmacokinetic equations and rapid modeling of pharmacokinetic processes. At its core, a software program is a set of instructions written in a computer language. The computer’s operating system must support the computer language of the software in order for this software to function properly. Accordingly, some software may only work in a Windows-based operating system (OS) while others may have been designed to work in Windows, Apple OS, or Linux. It is important to know the software requirements in order to properly choose the software that is most appropriate for the computer that will run the software packages.
These software programs simplify tedious calculations and allow more time for the development of new approaches to data analysis and pharmacokinetic modeling. In addition, computer software is also used for the development of experimental study designs, statistical data treatment, data manipulation, graphical representation of data, pharmacokinetic model simulation, and projection or prediction of drug action.
The improvements in computing have allowed for the estimation of pharmacokinetic (PK) and pharmacodynamic (PD) parameters from increasingly complex PK/PD models. Complex PK/PD and PBPK models are being elaborated today, where they would have been impossible to apply 30 years ago due to the slow computation time (months) in order to obtain parameters. Consequently, these improvements in conjunction with improvements in the analytical analysis of systemic drug concentrations and the capturing of pharmacodynamic parameters have led to a much better understanding of the pharmacokinetics and pharmacodynamics of drugs during drug development. Furthermore, the increased speed of the computer’s processors has allowed many more scientists the freedom to simultaneously analyze concentration data (PK) as well as response data (PD) on their personal computers, as most PCs are fast enough to run PK software packages compared to 30 years ago when these PK software packages were often installed on dedicated PK computers or mainframes.
COMPARTMENTAL AND NONCOMPARTMENTAL ANALYSES
In order for the user to decide which PK software ...