Use of Mixed Micelles in Micellar Electrokinetic Chromatography Method for Determination of Dexamethasone, Prednisolone and Triamcinolone in Pharmaceutical Formulations

The unregulated consumption of corticosteroids causes significant adverse effects on human health. Therefore, it is important to develop methodologies that allow their analysis in pharmaceutical matrices with competitive analysis times and costs. The determination of corticosteroids by micellar electrokinetic chromatography (MEKC) using a background electrolyte (BGE) composed of phosphate buffer and a micellar pseudo-stationary phase constituted by a mixture of surfactants is proposed as an alternative quantification technique. The variables involved in the BGE: phosphate concentration, surfactant (sodium dodecyl sulfate (SDS) or sodium lauryl ether sulfate (SLES)), sodium taurocholate (STC) and the pH value were optimized using a Taguchi L9 (34) experimental design. Employing the optimal BGE, the separation of the three corticosteroids is possible in a linear range of 1.05–10.0 mg L−1, with limits of detection (LOD) of 0.28–0.35 mg L−1. The relative standard deviation (RSD) values obtained for the repeatability (n = 3) and intermediate precision (n = 9) were less than 5.0%. Pharmaceutical formulations (ointments, injectable solution and ophthalmic solution) were analyzed using the proposed methodology (MEKC) and the official methodology (high-performance liquid chromatography, HPLC), and no significant differences were found between the corticosteroid contents obtained from both methods.