Investigation of anticancer drug lapatinib and its interaction with dsDNA by electrochemical and spectroscopic techniques

The electro-oxidation mechanism of lapatinib (LPT) at a glassy carbon electrode (GCE) was studied using various voltammetric techniques. The effects of pH and scan rate on LPT signal were determined in detail by cyclic voltammetry; as a result, the first and the second peaks were found diffusion and adsorption controlled, respectively. LPT exhibited three anodic peaks at 0.76 V, 0.95 V and 1.22 V by differential pulse voltammetry and two electrons were transferred for each peak. The oxidation of LPT was compared with some model compounds which contained aromatic amine structures. The possible electrooxidation pathway was also proposed. The electrochemical biosensor was designed in order to show the interaction between ct-dsDNA and LPT. For better understanding of the interaction mechanism between LPT and ct-dsDNA, spectroscopic techniques were performed. The binding constant (K) between LPT and DNA was calculated as 6.03 × 105 M−1, 4.20 × 105 M−1 and 3.50 × 104 M−1 for electrochemical, UV–vis spectrophotometric and fluorescence spectroscopic techniques, respectively. Ultimately, based on electrochemical and spectroscopic methods, it was confirmed that LPT could intercalate into the dsDNA helix.