Identification of pharmacokinetic parameters of two compartment open model with first order absorption.

This paper deals with the estimation of pharmacokinetic parameters of a two-compartment open model with first order absorption from plasma level data. The eigen-values of the characteristic matrix of the given system are obtained by transforming them into a single variable and the global minimum of the deviation (for plasma concentrations) from the observed values is obtained through the solution of linear relations involving the eigen-values. The distribution volume and the lag time are also identified. Finally, the uniqueness of the absorption rate constant is obtained by the minimum energy principle. The model is tested for different sets of data for the drug Guanfacine, an antihypertensive drug. The results are compared to those obtained by the SAMM program.