Molecularly Imprinted Potentiometric Sensor for Nanomolar Determination of Pioglitazone Hydrochloride in Pharmaceutical Formulations

Pioglitazone Hydrochloride (PG) is an insulin-sensitizing drug and is indicated for the treatment of type II diabetes. In this study, newly molecularly imprinted electrochemical sensors were constructed for the potentiometric determination of PG in the pharmaceutical formulations (Diabetonorm® 45 and 15 mg) with high accuracy and precision. The MIP particles (ionophore) were prepared by using the PG drug as a template, acrylamide (AC) or methacrylic acid (MAA) as a functional monomer, and ethylene glycol dimthacrylate (EGDMA) as a cross-linker. The best MIP was synthesized from AC as a functional monomer, AC-MIP. The best sensor (CPEs) was formulated from graphite (47 wt%) as a carbon source, AC-MIP (5 wt.%) as an ionophore, PMA (1 wt%) as an ion-exchanger, DNPOE (47 wt.%) as a conductive oil so-called plasticizer. The best CPE electrode exhibited response slope to the Nernstian slope of 63.0 mV Decade⁻¹, linear dynamic range of 10⁻⁸–10⁻⁴ M with the detection limit of 1.0×10⁻⁸ M, along with high reversibility, short response time 30 sec, and a long lifetime. The constructed biosensors showed high selectivity against similar interfering species (e. g. arabinose, galactose, lactose, maltose, glucose, Ba²⁺, Cu²⁺, Na⁺, Zn²⁺, Mg²⁺, Fe²⁺, Ca²⁺, NH₄⁺).