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.

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► 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.