Differential dynamic potentiometry with ion selective electrodes: A tool for drug fingerprinting

Differential dynamic potentiometry (DDP) is a novel potentiometric technique, which consists of recording the dynamic potential difference between two ion-selective electrodes (ISEs). In this article, we describe its application to studying the dynamic contribution of beta-cyclodextrin (β-CD) to the potential response of drug-selective electrodes. Surprisingly, DDP responses in serial calibration mode were characteristic for each individual drug, and might serve as drug-fingerprints. Also, non-monotonic DDP responses were obtained using single concentration step experiments, and these were used for quantitative drug analysis. Theoretical simulations of the DDP responses based on a reported dynamic diffusion model allowed both types of the experimentally obtained signals to be predicted.

Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Differential dynamic potentiometry (DDP) provides reproducible drug-fingerprints. ► Non-monotonic DDP responses allow determining drugs in pharmaceuticals. ► DDP responses arise from different dynamic behaviours of two electrodes. ► A theoretical dynamic diffusion model predicts DDP responses.