Determination of indacaterol from inhaler capsules by square-wave voltammetry at the surface of the boron-doped diamond electrode

This research paper presents an electroanalytical investigation using the voltammetric method to quantify indacaterol maleate (IND) employing an unmodified boron-doped diamond (BDD) electrode. IND exhibited a distinct, irreversible oxidation peak at approximately 1.06 V (vs. Ag/AgCl) in a 0.1 mol L-1 phosphate buffer solution (PBS) with a pH of 2.5, as demonstrated by cyclic voltammetry (CV). A hypothetical mechanism for the electro-oxidation of IND, based on data gathered from CV investigations, was suggested. The square wave-adsorptive stripping voltammetric technique achieved acceptable linearity in PBS (pH 2.5) at approximately 0.90 V. The methodology demonstrated linearity within the concentration range of 1.0 to 30.0 mu g mL-1 (equivalent to 1.97x10-6-5.89x10-5 mol L-1) and yielded a limit of detection (LOD) of 0.22 mu g mL-1 (equivalent to 4.33x10-7 mol L-1). The proposed method's applicability was assessed through the sensing of IND in drug formulations.