The present study aimed to simultaneous determination of clobetasol 17-propionate (CB) and betamethasone 17-valerate (BM) in skin whitening creams purchased via internet from Iraqi market. The chromatography was performed with Zorbax Eclipse Plus C18 (150 x 3.0 mm ID, 5µm), mobile phase acetonitrile (70): water (30), flow rate of 1 ml/min and an UV detector at 240 nm. The method was validated in terms of linearity, selectivity, precision, accuracy, limit of detection and quantification and stability of working solutions. The analytical method proved to be linear in the range of 1-40 µg/ml for both CB and BM. The limits of detection and quantification for CB and BM were (0.024 µg/ml, 0.075 µg/ml) and (0.035 µg/ml, 0.107 µg/ml), respectively, which revealed the sensitivity of the method. The precision, accuracy and stability study of working solutions of the method were between 0.52 to 1.93%, 97.87 to 100.55% and 0.48 to 1.72%, respectively. The results revealed that all purchased samples from beauty/cosmetic shops contained different levels of CB and/or BM. Moreover, the mixed preparations which purchased from the pharmacies also contained either CB or BM. A new and restrict regulations must be implemented to ban the use of topical corticosteroids without prescription.
Key words: Betamethasone, Clobetasol, HPLC, validation, whitening cream
|
