Direct injection micellar liquid chromatographic method for the analysis of corticosteroids in creams, ointments and other pharmaceuticals Original Research Article

The corticosteroids beclomethasone, budenoside, dexamethasone, fludrocortisone, fluocinolone, hydrocortisone and triamcinolone, appear in pharmaceuticals as creams, gels and ointments that are used topically as anti-inflammatory, antipruritic and vasoconstrictor agents. This work develops a simple and reliable micellar liquid chromatography (MLC) method for determining the seven corticosteroids using direct injection. The retention behaviour of the analytes was studied in mobile phases containing sodium dodecyl sulfate and modifiers (propanol, butanol or pentanol), in a C18 column (125 mm×4.6 mm). The MLC optimum mobile phase was 0.10 M SDS–4% butanol–pH 7, in which the retention factor was lower than 12 min. Linearities (r>0.999), repeatabilities and intermediate precision (<1.5%) were satisfactory. The method was applied to the determination of corticosteroids in pharmaceuticals, with recoveries, as regards the labelled amounts, within the 95–105% range. The results were compared with those obtained with a reference method that uses methanol–water (70:30), and gives higher retention factors.