The redox mechanism investigation of non-small cell lung cancer drug: Erlotinib via theoretical and experimental techniques and its host-guest detection by β-Cyclodextrin nanoparticles modified glassy carbon electrode

Erlotinib (ERL) is a tyrosine kinase inhibitor which prevents growing of cancer cells. The electrochemical oxidation mechanism of ERL was studied in details using cyclic voltammetry. Cyclic voltammetry, differential pulse and square wave voltammetric techniques were applied for sensitive, fast, precise determination of ERL. Adsorptive stripping square wave voltammetry was selected and applied to the assay of ERL in pharmaceutical dosage forms. Quantitative application and its validation were realized via β-Cyclodextrin nanoparticles modified glassy carbon electrode in 0.1 M phosphate buffer pH 3.0 in the presence of 20% methanol. The adsorptive stripping square wave voltammetry provided linear response within the concentration ranges 1.00 × 10−8 M - 8.00 × 10-6 M (r = 0.999) with LOD and LOQ values 1.07 × 10-9 M and 3.58 × 10-9 M, respectively. The recovery of erlotinib in Tarceva® tablets was 100.38%. In addition, computational studies were exerted to complement to the analytical studies, The molecular electrostatic potential surface and frontier molecular orbitals have been calculated at the DFT level and on B3LYP/6‑31+G* to elucidate the ERL oxidation behavior. The results shown that the theoretical data were consistent with the proposed oxidation mechanism of ERL.