Abstract
Afatinib (AFT) is a potent and highly selective drug used to treat various solid tumors including non-small cell lung cancer (NSCLC). To ensure safe and effective treatment of cancer patients with AFT, its plasma concentrations should be monitored. Thus, sensitive immunoassays are required for measuring AFT concentrations in plasma samples. In this study, two different formats of heterogeneous fluorescent immunoassays were developed and validated for AFT bioanalysis. These assays were microwell-based fluorescence immunoassay (FIA) using fluorescence plate reader and kinetic exclusion assay (KinExA) using KinExA 3200 immunosensor. Both FIA and KinExA were developed using the same reagents: mouse anti-AFT antibody, solid-phase immobilized AFT conjugated with bovine serum albumin protein (AFT-BSA), and goat anti-mouse IgG labelled with fluorescein isothiocyanate (FITC-IgG) for signal generation. The analytical performances of both assays were comparatively evaluated, and the results revealed that although both assays had comparable accuracies, KinExA was superior to FIA in terms of sensitivity and precisions. Moreover, both FIA and KinExA were better alternatives to the existing chromatographic methods for bioanalysis of AFT. The proposed FIA and KinExA are anticipated to effectively contribute in ensuring safe and effective treatment with AFT in clinical settings.