Revealing the correlation between structurally different drugs' efficacy and their affinity chromatographic behaviors

To understand thoroughly the mechanisms of drugs’ efficacy to the targeting receptor, it is crucial to determine the thermodynamics and kinetics of drug-receptor interactions. Herein, the cysteinyl leukotriene receptor 1 (CysLTR1) was immobilized onto silica gels for the column packing, and multiple affinity chromatographic approaches like frontal chromatography, injection amount-dependent method and nonlinear chromatography were employed to determine the retention behaviors of distinct structural antagonist drugs and to measure their binding constants toward the immobilized CysLTR1. The association equilibrium constants KA in the rank of montelukast < zafirlukast < pranlukast obtained from three affinity chromatographic methods and their dissociation rate constants  as montelukast > zafirlukast > pranlukast from nonlinear chromatography, which were related to their inhibition potencies of montelukast < zafirlukast < pranlukast to CysLTR1. Additionally, thermodynamic analysis indicated that the three antagonists were spontaneously bound to CysLTR1 and their bindings were mainly driven by hydrogen bonds and van der Waals forces, which were further validated by molecular docking method. Among the three antagonists, pranlukast with the strongest binding strength and the slowest off-rate kinetics toward CysLTR1 might be protected from metabolism or excretion in living organisms, serving as a most prominent drug in the treatment of the inflammatory diseases. Our work provides a new method for predetermination of structurally different drugs’ efficacy, which is based on the equilibria and kinetics of drug-receptor interaction measured by affinity chromatography.