Corticosteroids are hormones present in the body reducing the harmful inflammatory response of the organism. Synthetic corticosteroid molecules are used for the treatment of systemic or local chronic or acute diseases associated with inflammation and pain. For the local application on the skin, we incorporate different corticosteroids of various potency into creams, ointments, lotions or gels. Less potent topical corticosteroids can be used for treating burns and allergic skin diseases, and highly potent ones on the other hand for the treatment of e.g. thickened keratotic dermatoses. If we are applying them on the skin for too long or too frequent, it can lead to reversible or even irreversible local atrophy of the skin and unwanted systemic effects on the hypothalamic-pituitary-adrenal axis. In my master's thesis, I addressed a problem of illegal products on the market, which are supposed to be based on herbs, but actually contain synthetic corticosteroids. More exposed are children who have greater skin area and elderly people, with a thinner, easily absorbing skin barrier. Daily uncontrolled, without supervision application of corticosteroids on the skin can cause a worsening of the skin disease due to the formation of irreversible skin atrophy and the inhibition of skin cell renewal, in addition a weakened immune response can lead to the development of many fungal infections. We have received a sample of unknown cream, which was supposed to be of natural, plant origin, without the presence of corticosteroids. For the analysis of creams we developed a simple, fast and robust method with the HPLC / MS system, with this method we also quantified the analytes. We used a reverse phase column in and optimized the HPLC method for separating the chosen corticosteroid molecules. For individual samples we were detecting the ionized analytes and recorded the mass spectra with a single quadrupole mass spectrometer, and in addition we also evaluated analytes content with the calibration curve method. During the practical work we were faced with the problem of the sample preparation particularly due to the insolubility of the cream base, but the analyte itself was soluble in the mixture of acetonitrile and water. We had to extend HPLC method in order to obtain an appropriate separation of all the proposed corticosteroid molecules, for the quantification we have chosen adduct of sodium ion molecules in most cases. We found a betamethasone dipropionate in tested cream at approximately ten times lower concentrations than are the contents in regular pharmacy creams, which is already sufficient for the adverse effects of such a potent molecule.?
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