A simplex procedure for fitting nonlinear pharmacokinetic models.

A convenient and readily modifiable nonlinear regression procedure, based on two Pascal programs, is described. This procedure, suitable for running on both microcomputers and mainframes, is presented as utilized in ongoing clinical pharmacokinetic work. One program uses the simplex algorithm to fit data conforming to any of six models of drug disposition. In addition to the regression terms, it generates logarithmic plots of the function and calculates derived kinetic variables of drug distribution, elimination and clearance. This program is driven by another which batches together required data and parameter information to build a control file for solving multiple curve-fitting problems.