Fast on-site simultaneous electroanalysis of fusidic acid and betamethasone in pharmaceuticals and water samples using novel stochastic platform

Fusidic acid and betamethasone are two pharmaceutically active compounds found in topical dosage forms. Sometimes, they can unintentionally wind up in surface water via skin washing. Therefore, a stochastic platform based on a type of calix[4]arene and polyaniline modified screen-printed electrode was developed for their on-site analysis. For both analytes, remarkably wide dynamic ranges (1.0 × 10⁻¹⁷–1.0 × 10⁻⁴ for fusidic acid, and 1.0 × 10⁻¹⁸–1.0 × 10⁻³ for betamethasone) and considerably low limits of quantitation (1.0 × 10⁻¹⁷ for fusidic acid, and 1.0 × 10⁻¹⁸ for betamethasone) were attained. Moreover, the proposed platform was successfully applied to real samples such as topical dosage form and surface water, obtaining recovery values higher than 90.0 % with relative standard deviation values below 0.1 %.