Electrochemical determination of budesonide: a common corticosteroid used to treat respiratory diseases such as COVID-19 and asthma

The outbreak of the COVID-19 pandemic has adversely affected the most important areas of the modern world. One of the challenges related to counteracting the effects of the pandemic it was necessary to develop methods for the quantitative determination of pharmaceuticals used in the treatment of patients suffering from this disease and its long-term effects. Budesonide (BUD) is a widely available and inexpensive corticosteroid used extensively not only among people suffering from COVID-19, but also asthma and other respiratory diseases. A significant increase in the consumption of drugs containing this component requires the development of new BUD determination methods, especially in real samples. This paper presents a new voltammetric method for BUD determination at renewable silver amalgam film electrode (Hg(Ag)FE). The electrochemical measurements were conduced in the supporting electrolyte containing 80% of methyl alcohol, 0.04 mol L −1 Britton–Robinson buffer (pH 3.0) and 20 mg mL −1 of NaClO 4 under optimized differential pulse voltammetry (DPV) parameters. Detailed studies of the behaviour of the BUD on the surface of Hg(Ag)FE demonstrated the quasi-irreversible nature of the diffusion-controlled, two electrons and two protons reduction process. A calibration curve in the range from 1.0 to 290 µg mL −1 shows limit of detection and limit of quantification equal to 0.06 and 0.21 µg mL −1 , respectively. The impact of numerous interferences over a wide range of concentrations on BUD signals was analysed and evaluated. The utility of the proposed method was verified by the quantitative analysis of BUD in two pharmaceutical products and the spiked water samples. Graphical abstract