The efficient use of NONLIN for unbalanced multiple dose data.

One of the uses of pharmacokinetic modeling is the fitting and prediction of blood levels after multiple dosing. The equations that govern this process are readily available for the case of equally spaced dosing intervals. For unequally spaced intervals, some rather inefficient methods have been suggested for use with NONLIN (1). This article shows how to implement parameter estimation and fitting of such data by means of NONLIN by summing the appropriate single-dose equations.