LC-MS method for the simultaneous determination of six glucocorticoids in pharmaceutical formulations and counterfeit cosmetic products

A screening method based on liquid chromatography-electrospray mass spectrometry for the simultaneous determination of six corticosteroids (betamethasone 17-valerate BM 17-V, beclomethasone BC, beclomethasone dipropionate BCDP, methylprednisolone MP, budesonide BD, flunisolide FN) was developed in order to control their illegal use in cosmetic and natural products. Indeed, despite corticosteroids are banned in cosmetics, counterfeit products might be present on the market, representing a health hazard. Therefore, effective analytical methods are required to rapidly screen over the counter products in health care shops for counterfeit corticosteroids. The analytical method involves the employment of a Waters Synergy C18 column (150mm×2.0mm I.D.) by using the following mobile phase: A (0.1% formic acid in acetonitrile), B (0.1% formic acid in water) in a linear gradient (from A-B 25:75, v/v to A-B 95:5, v/v in 30min) at the flow rate of 0.3mL/min. The detection was performed with an ion trap (IT) mass spectrometer in positive polarity, total ion current (TIC) and tandem mass modalities for qualitative purpose; single ion monitoring (SIM) mode was used for quantitative analysis on the ESI generated most abundant ion for each steroid. The method was fully validated in terms of precision, detection and quantification limits, linearity, recovery, and it was applied to the identification and quantification of corticosteroids in pharmaceutical formulations and cosmetic products. The mean recovery of BM 17-V, BC, BCDP, MP, BD and FN were found to be 101.3, 101.5, 98.8, 98.9, 98.1, 99.0%, respectively. Limits of quantitation (LOQ) were comprised in the range 29-95ng/mL. To the best of our knowledge, for the first time this mix of glucocorticoids were simultaneously determined in cosmetic products by using a fully validated method. BMV, in its two isomeric forms BM 17-V and BM 21-V, was found to be illegally present in one cream sample (A) with the total concentration level of 0.036% (w/w).