System Identification of the Low-Dose Kinetics of p-Aminohippuric Acid

Abstract

Summary: The renal clearance of^-aminohippuric acid, due to tubular secretion in addition to glomerular filtration, can only be determined by kinetic experiments. Maximal information can be gained from observed temporal marker concentration profiles by fitting dynamic mathematical models of the processes involved, such as absorption, distribution, and elimination, to the kinetic data. Thereby the values of the system constants, such as fractional elimination or fractional distribution rates, and their accuracy measures are determined by methods which are based firstly on measured time-dependent data elicited in an individual test object by perturbing inputs and secondly, on mathematical formulations of prior knowledge of the underlying physiological system. Such methods of model adaptation are called system identification.

Determination of Renal Reserve Capacity by Identification of Kinetic Systems

“…The mathematical solution of the general dynamic model for the required inputs and initial conditions of these markers, and the problem of the necessary experimental protocols is described in [5,6]. The pharmacokinetic modelling approach using optimal experimental protocols has been found as the method of unequalled precision in a recent reappraisal of various approaches for GFR determination [2].…”