Abstract

This study describes the kinetics and evaluation of thermodynamic parameters of bovine serum albumin (BSA) and tropicamide (TPA) interactions, by using quartz-crystal microbalance (QCM) technique, under similar physiological status. BSA was immobilized on the gold electrode surface of a QCM by using cystamine (Cys) and glutaraldehyde (GA) as crosslinking agent. The immobilizing steps were followed by cyclic voltammetry technique. A flow injection analysis set-up was applied for injection of the drug solutions into the fluid system. Kinetics of the interaction were interpreted by zero and pseudo first-order kinetic models, depending on TPA concentration and temperature. The binding constants (k1 = 9.12, 6.55 and 6.8 mol-1Ls-1), dissociation rate constants (k-1 = 0.0028, 0.0049 and 0.0102 s-1), the binding equilibrium constant (K = 3257, 1337 and 635 mol-1L) and the thermodynamic parameters of the interaction were estimated at different temperature (293, 303 and 310 K respectively). The results revealed that hydrogen bonding and Van der Waals forces are the major types of interactions of between BSA and TPA.