Immobilization of alpha1-acid glycoprotein for chromatographic studies of drug-protein binding II. correction for errors in association constant measurements.

A new method for the immobilization of alpha(1)-acid glycoprotein (AGP) in high-performance liquid chromatography (HPLC) columns was recently described for applications such as drug binding studies. Part of this earlier work used self-competition zonal elution studies to measure association equilibrium constants between immobilized AGP and R- or S-propranolol. It was later found that analysis of these data by a common equation derived for linear elution conditions gave erroneous values for experiments actually conducted under nonlinear conditions. This report discusses the nature of this error and uses frontal analysis to estimate the true binding strength between R- and S-propranolol and HPLC columns containing immobilized AGP.