Serum-protein effects on the detection of the β-blocker propranolol by ion-transfer voltammetry at a micro-ITIES array

Abstract

In this work, the effect of the serum protein, bovine serum albumin (BSA), on the detection of propranolol in artificial serum by ion-transfer voltammetry at an array of micro-interfaces between two immiscible electrolyte solutions (microITIES) is presented. Cyclic voltammetry (CV), differential pulse voltammetry (DPV), and differential pulse stripping voltammetry (DPSV) were examined for the detection of low concentrations of propranolol. Both CV and DPV had an interference effect from BSA, manifested as lower currents in the presence of the protein. DPSV proved to be the most effective technique, enabling the detection of 0.05 microM propranolol in the presence of BSA. The DPSV method employed a preconditioning step as well as a preconcentration step followed by the analytical signal generation step. The latter was based on the back-transfer of the drug across the microITIES. The preconcentration step was crucial to prevention of the adverse effects of BSA on the voltammetric detection. These results demonstrate that serum-protein effects on drug detection at low concentrations can be eliminated by use of DPSV at arrays of microITIES. CVs of propranolol with increasing concentrations of BSA revealed the influence of the drug-protein binding interaction, with decreases in current but no change in transfer potential. Therapeutic concentrations of propranolol were detected, demonstrating the viability of this approach for bioanalytical investigations.